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Biomedical Engineering

  • 2011
    Keenan, Kathryn E.; Beaupré, Gary Scott; Delp, Scott; Gold, Garry E.
    Human articular cartilage can degrade, losing functional quality and eventually exposing bone surfaces; when significantly advanced, this cartilage degradation can be diagnosed as osteoarthritis (OA). Currently, knee OA can be diagnosed only when the disease is advanced and the patient is suffering from pain. There is no cure for knee OA, nor are there prevent preventative therapies; current treatment strategies relieve the pain of OA or completely replace the knee joint. To evaluate potential therapies and treatments, we need a method that can identify and measure changes to cartilage prior to the onset of degradation. Magnetic resonance imaging (MRI) is a potentially powerful tool to non-invasively evaluate the progression of knee OA by mapping MR image parameters to molecular and material properties that are known to change with disease. The goal of this dissertation was to determine MR image parameters that can be used to evaluate the progression of OA. We examined the biphasic and viscoelastic models of cartilage to determine cartilage material properties from indentation creep tests. We compared initial elastic modulus and cartilage macromolecules to MRI parameters, specifically T2 and T1rho relaxation times and T1rho dispersion. We determined that a predictive model based on T1rho relaxation time maps, which accounts for T2 relaxation time and the effects of age, may estimate longitudinal trends in GAG content in the same person. In addition, a simple T1rho dispersion estimate has the potential for substantial clinical impact by measuring changes in cartilage initial elastic modulus and macromolecules non-invasively. This work is an important step toward developing clinical methods for evaluating cartilage functional condition, and in turn, to advance work towards preventing and treating knee OA.
  • 2011
    Chung, Minsub; Boxer, Steven G.; Fuller, Gerald G.; Swartz, James R.
    Many cellular processes including cell-cell communications and regulated membrane transport are mediated by membrane proteins and depend upon the ability of lipid membranes to be a differentially permeable barrier. However, the roles and function of membrane proteins are often difficult to study due to the complexity of the native membranes and lack of reliable and flexible artificial model lipid membranes. Supported lipid bilayers (SLB) have been used as a model system to study biological membrane behavior and the structure and function of membrane proteins and receptors in a simpler context apart from the complex cellular environment. Although SLBs have the advantages of simple formation, easy handling and are well-suited for investigation by a suite of surface sensitive methods due to their planar geometry, the close proximity of the lower leaflet to the solid support often leads to unfavorable interactions with integral membrane proteins. This causes distortion of the protein conformation and possible loss of its reactivity and function. Moreover, this interaction with the substrate often traps proteins and reduces their mobility in the membranes. Recognizing this limitation, we have developed a new model membrane architecture in which the DNA-tethered lipid bilayer is either to fixed DNA on a surface or to laterally mobile DNA displayed on a supported bilayer. This separates the lipid membranes from surface interactions and provides a more favorable environment for integral membrane protein with large globular domains. With mobile DNA hybrid tethers, stable tethered bilayers were made with specific lipid composition, while those with fixed tethers are stable regardless of membrane composition. The mobile tethers between a tethered and a supported lipid bilayer offer a particularly interesting architecture for studying the dynamics of membrane-membrane interactions. By careful choice of composition, improved stability was obtained and we can investigate the lateral segregation of DNA hybrids when different lengths are present. Based on a theoretical model, the effects of population, length and affinity of DNA complexes are simulated and described. This model system captures some of the essential physics of synapse formation and is a step toward understanding lipid membrane behavior in a cell-to-cell junction. To demonstrate the excellent environment provided by DNA-tethered membranes for studying transmembrane proteins free from any surface interactions, the behavior of a transmembrane protein, the photosynthetic reaction center, reconstituted in the DNA-tethered membranes is investigated. Inspired by DNA-mediated membrane fusion studies of our group, we applied the DNA-machinery to achieve fusion of small (~ 100 nm) proteoliposomes for delivery of membrane proteins to either giant vesicles or DNA-tethered planar lipid membrane patches. The diffusion behavior of delivered proteins is measured and compared with those in supported bilayers. Also, the protein activity and orientation before and after fusion is analyzed. This will offer a feasible method to incorporate intact membrane proteins to already formed model membranes. In addition, the behavior of proteins during the fusion event will provide insight into the mechanism of DNA-mediated lipid membrane fusion. The geometry of our model membrane system directly mimics that of a neuronal synapse. We expect that this architecture will be readily transferable to other model membrane fusion systems, including systems using reconstituted SNARE proteins. Consequently, it will be of considerable interest to a wide range of researchers.
  • 2010
    Wang, Aaron Sheng-Chieh; Liang, David; Taylor, Charles A.; Zarins, Christopher K.
    Trauma patients require rapid diagnosis and treatment of hemorrhage. In the hospital, experienced sonographers can reliably diagnose vascular injury using duplex ultrasound. In trauma settings, such as the battlefield, a portable ultrasound device with an automated algorithm to detect bleeding would be useful for medics. Thus, an increasing interest in computer-aided bleed detection led to efforts in quantifying sonographic signatures of abnormalities at the site of vascular injury. However, since trauma patients often present with large areas of injury, there is a need to develop and evaluate bleed detection strategies for ultrasound that more efficiently assess a large vascular tree. The goal of this Ph.D. research dissertation is to address this need. The studies primarily focused on the upper extremity vasculature, specifically the brachial bifurcation, because the leading cause of preventable deaths due to vascular trauma has been exsanguinations from extremity injuries. The overall approach was to characterize normal blood flow with a well-established power law model and identify flows that deviate from the model. The power law states that blood flow is proportional to the vessel diameter raised to a power index k, where k is defined by the bifurcation geometry. A bleed detection metric, called the "flow split deviation" (FSD), was defined to quantify the flow deviations from the power law. Validation of this approach was undertaken in four steps. The first involved demonstrating that the power law model appropriately describes the normal brachial bifurcation and flows in man. The utility of the bleed metric was then evaluated with 3D computational models of bleeds. Finally, the proposed detection algorithm was applied on the early proof of concept humans in arteriovenous fistulas (AVF) of dialysis patients and in in vivo rabbit bleed models. A study with normal human subjects was used to determine that the best-fit k for the brachial bifurcation was 2.75, which is in agreement with other vasculatures previously studied. A k=2.75 power law was then shown to adequately predict forearm blood flows for both resting and exercise physiological states. The correlation coefficient R between predicted and measured normal flows was 0.98. Computational models suggested that FSD was a good indicator of the severity of bleed downstream from the bifurcation. In the patient case study, the bleed metric easily distinguished between normal arms and those with newly placed wrist AVFs, which caused on average an order of magnitude increase in flow deviations. Introduction of different femoral bleed rates in rabbits demonstrated good sensitivity and specificity of the bleed metric when applied to moderate lower extremity bleeds. Bifurcation FSDs can serve as a quantitative signature of bleeding and, moreover, as a strategic way to survey large vascular trees by following abnormal branch points to the likely source of hemorrhage. This approach can complement other quantitative sonographic methods to create a comprehensive, automated, ultrasound-based algorithm for vascular trauma detection.
  • 2011
    Cocker, Eric David; El Gamal, Abbas A.; Kenny, Thomas W.; Schnitzer, Mark Jacob.
    A central goal in neuroscience is to explain animal behavior in terms of causal cellular processes. It has been a longstanding challenge, however, to simultaneously track behavior and the cellular dynamics driving it. In this thesis, I discuss how a series of one- and two-photon fluorescence microscopes, based on gradient refractive index (GRIN) lenses, were developed to meet this challenge. The predominant difficulty in the design of these microscopes was how to take a traditional bench top microscope and shrink it to a size small enough for a mouse to easily carry on its head, a limit of 3 grams. We chose mice as our design target due to the wide availability of genetically modified mouse models for the study of cognitive functions, animal behaviors, and disorders of the nervous system. The earlier devices, relying on fiber optics to bring light to and from the animal, met with limited success but still provided useful insight in the development of the surgical techniques and analytical tools necessary for later successful experiments. In contrast, our latest system fully integrates the entire light pathway onto the head of mouse, eliminating many of the remaining roadblocks to truly freely-moving imaging. This device has enabled novel observations of both microcirculatory and neuronal calcium dynamics in the cerebellum of freely-moving mice at frame rates up to 100 Hz. As the genetic toolbox for mice continues to mature, these miniaturized microscopes will facilitate a wide set of future studies of how cellular function in the brain varies across different behavioral and physiological states.
  • 2011 Atypon
    Zhu, Xiaolu; Ells, Anna L.; Rangayyan, Rangaraj M.
    Fundus images of the retina are color images of the eye taken by specially designed digital cameras. Ophthalmologists rely on fundus images to diagnose various diseases that affect the eye, such as diabetic retinopathy and retinopathy of prematurity. A crucial preliminary step in the analysis of retinal images is the identification and localization of important anatomical structures, such as the optic nerve head (ONH), the macula, and the major vascular arcades. Identification of the ONH is an important initial step in the detection and analysis of the anatomical structures and pathological features in the retina. Different types of retinal pathology may be detected and analyzed via the application of appropriately designed techniques of digital image processing and pattern recognition. Computer-aided analysis of retinal images has the potential to facilitate quantitative and objective analysis of retinal lesions and abnormalities. Accurate identification and localization of retinal features and lesions could contribute to improved diagnosis, treatment, and management of retinopathy.
  • 2008
    Russomano, Thais; Dalmarco, Gustavo; Falcão, Felipe Prehn.
  • 2005 CRCnetBASE
    Holder, David.
  • 2010
    Esfandyarpour, Hesaam; *Pease, R.; Davis, Ronald W.; Pianetta, Piero.
    The Human Genome Project was accomplished by a reduction in the cost of DNA sequencing by three orders of magnitude. Further cost reductions are required for sequencing to become a standard tool in clinical medicine and to enable personalized medicine via individual genome sequencing. The current cost varies between $50k to $100k over a period of months; depend on the technology, accuracy and read-length. It is desired to reduce the cost to $1000 per genome to enable profiling of individuals genome. To achieve this goal, a highly integrated platform with simplified chemistry is required. In this dissertation, we introduce a novel method for DNA sequencing based on electrical detection of polymerization reaction, called "Thermo/pH sequencing". Our proposed method is based on the direct measurement of the heat release or the pH modulation (change of H+ ion concentration in the solution) during DNA extension. For high throughput DNA sequencing, DNA strands are immobilized to small micron-size beads in a microfluidic platform. The DNA-beads are in a reaction mixture in contact with an array of sensitive micro-machined heat or pH sensors, which detect the electrical signature from incorporation of a complementary base (dNTP) in the presence of appropriate reagents (DNA polymerase, and polymerase reaction buffer). This results to a label-free, long-read and fast chemistry; 10x reduction in reagent cost with 10x increase in throughput can potentially yield to significant improvement in the cost of genome sequencing to less than $1000. In addition, substituting optical detection set-up with microelectronic sensor reduces the capital cost of sequencing instruments from $500k to less than $50k. We demonstrate the proof of concept for this technology at large scale. Then we describe the development of an appropriate microfluidic platform and two micromachined electrical biosensors that employ electrical detection for heat or pH detection. Both versatile platforms can be multiplexed and have the potential of providing rapid and inexpensive measurements without any compromise in the sensitivity, making them good potential candidates for use in the clinical setting. We report a chip-based integrated differential microfluidic nanocalimeters with on-chip injection and multiplexing unit, capable of characterizing the heat of reaction with unprecedented 2-nW resolution in 1 Hz bandwidth for nanoliter scale samples. We successfully demonstrate DNA Thermosequencing with sequential injection of different nucleotides into the integrated microfluidic calorimeter device. In addition, the device can serve as a powerful tool to characterize a variety of the biomedical processes, such as metabolic activities of microorganisms, living cells and catalyzed reactions. We also present a microfabricated device in microfluidics for pH sequencing, called nanoneedle biosensor. The key element for this device is a 10nm wide gap on the end of the needle of total diameter about 100nm. Any change in the population of molecules in this gap results in a change of impedance across the gap; single molecule detection should be possible. In addition, DNA-beads can be allocated iv near the sensors to measure the pH change during DNA extension. The design, fabrication, testing, optimization and a modified structure of the device for higher signal to noise ratio are presented. Toward an integrated sequencer platform, automation and reduced labor cost, higher throughput, accuracy and efficiency for genomics and proteomics analysis; further integration and optimization of the presented systems are required. We envision the integration of our CMOS-compatible devices with a CMOS integrated circuitry into a high throughput gene sequencer or proteomics system. The proteomics system enables multiplex analysis using an array of micro-channels for probing clinically relevant samples such as the human serum for various protein and nucleic acid biomarkers for cancer detection, and also the detection of pathogenic bacteria in solution.
  • 2006, 2010.
    Webster, John G.
  • 2015 Springer
    Bertassoni, Luiz E.; Coelho, Paulo G.
    This book offers a comprehensive overview of current challenges and strategies to regenerate load-bearing and calcified human tissues, including bone, cartilage,tendon, ligaments and dental structures (dentin, enamel, cementum and periodontal ligament). Tissue engineering has long held great promises as an improved treatment option for conditions affecting mineralized and load-bearing structures in the body. Although significant progress has been achieved in recent years, a number of challenges still exist. Scaffold vascularization, new biofabrication methods (3D printing, lithography, microfabrication), peptide conjugation methods, interface engineering, scaffold mechanical properties, iPS cells, organs-on-a-chip, are some of the topics discussed in this book. More specially, in the first section readers will find an overview of emerging biofabrication methods. In section 2, applied strategies for regeneration of (2.1) bone, cartilage and ligament, as well as (2.2) dentin, cementum, enamel and periodontal ligament are discussed across 14 chapters. While other volumes have addressed the regeneration of individual tissues, or exclusively focused on different regenerative strategies, the focus of this work is to bring together researchers integrating backgrounds in materials sciences, engineering, biology, mechanics, fluidics, etc, to address specific challenges common to regeneration of several load-bearing and calcified tissues. Therefore, this book provides a unique platform to stimulate progress in the regeneration of functional tissue substitutes. We envision that this book will represent a valuable reference source for university and college faculties, post-doctoral research fellows, senior graduate students, and researchers from R&D laboratories in their endeavors to fabricate biomimetic load bearing tissues.
    Also available: Print – 2015
  • 2011
    Ding, Sheng; Barron, Annelise E.; Heilshorn, Sarah; Swartz, James R.
    Recombinant proteins have been used widely in both basic research and biomedical applications including protein therapeutics and biomaterials. Many efforts have been devoted to the investigation of novel synthetic strategies for producing recombinant proteins for various applications, which is the focus of this dissertation. In the first section, a biosynthetic strategy was developed to produce collagenous proteins with post-translational modifications in E. coli. Collagen is the most abundant protein in human, and plays a dominant role in maintaining the biological and structural integrity. Recombinant expression of collagens and fragments of collagens is often difficult as their stability requires appropriate proline hydroxylation. Prolyl 4-hydroxylases (P4H) are ascorbate-dependent oxygenases that play key roles in collagen folding by catalyzing the post-translational hydroxylation of specific proline residues on target proteins to form (2S, 4R)-4-hydroxyproline. Thus far, the study of these post-translational modifications has been limited by the lack of a prokaryotic recombinant expression system for producing hydroxylated proteins. Unlike eukaryotic cells such as yeast and insect cells, bacterial cytoplasm cannot activate P4H, which requires an ascorbate co-factor that bacteria do not produce. By introducing a biosynthetic shunt to produce ascorbate-like molecules in E. coli cells that heterologously express human P4H, we have created a strain of E. coli that produces collagenous proteins with (2S, 4R)-4-hydroxyproline. Different levels of proline hydroxylation can be obtained by tuning culture conditions. We have verified that hydroxylation of collagenous materials produced in the new system leads to an increase in thermostability. Using this new system, we have observed hydroxylation patterns indicative of a processive catalytic mode for P4H that is active even in the absence of ascorbate. Our results provide insights into P4H enzymology, and create a foundation for better understanding how post-translational hydroxylation affects proteins. Further, we applied the novel E. coli expression system to produce a collagenous protein, adiponectin, which has many beneficial effects on obesity-related metabolic and cardiovascular disorders, and reverses insulin insensitivity. By introducing key post-translational modification enzymes to E. coli, we have endowed the expression system with capabilities of making necessary modifications on adiponectin for its correct assembly, and thus obtained biomimetic adiponectins. High-molecular weight (HMW) multimers of adiponectin have been obtained, and their biological activities of suppressing endothelial cell apoptosis have been confirmed with in vitro cell assays. In section 2, modular protein polymers have been created through genetic engineering and enzymatically crosslinked into hydrogels with tunable properties. The many challenges currently faced in regenerative medicine research require the development of new, modular biomaterial systems that can serve as scaffolds for cellular maintenance, expansion and growth, and which can be tuned by the user to mimic any necessary aspects of natural ECM to an optimal degree. Toward this goal, we have created a family of block co-polypeptides comprising amino acid sequence elements that allow mild enzymatic crosslinking into gels. These new families of protein polymers were designed to be linear, random coil, and contain either lysine or glutamine, which have the recognition substrates for transglutaminase (TG) crosslinking, evenly spaced along the protein backbone. Crosslinking occurred within two minutes upon the addition of TG under physiological conditions, as determined by particle tracking microrheology. The material properties of the gel can be tuned with the hydrogel composition to mimic cellular microenvironment of different tissues. Furthermore, in order to introduce biofunctionalities into the hydrogels, a versatile expression vector has been engineered that allows the insertion of bioactive protein domains into these block co-polypeptide. For example, a cell adhesion signal based on the RGD sequence from human fibronectin was incorporated. The RGD-containing hydrogel was successful in enhancing cell adhesion, and were also proven to be compatible with the culture of mesenchymal stem cells. The specific nature of these protein polymer precursors of the modular hydrogel composition allows tailoring of mechanical and biochemical properties, rendering these gels valuable for various tissue engineering applications.
  • 2007 Springer
    Bronner, Felix; Farach-Carson, Mary C.; Mikos, Antonios G.
  • 2008 CRCnetBASE
    Bednyi, G. Z.; Chebykin, A. IA; Karwowski, Waldemar.
    Ecological ergonomics / Marvin J. Dainoff -- Integrating cognitive and digital human models for virtual product design / Daniel W. Carruth and Vincent G. Duffy -- Time study during vocational training / Gregory Z. Bedny and Waldemar Karwowski -- The laws of ergonomics applied to design and testing of workstations / V.F. Venda, V.K. Kalin, and A.Y. Trofimov -- Day-to-day monitoring of an operator's functional state and fitness-for-work : a psychophysiological and engineering approach / Oleksandr Burov -- Identification of mental modules ; Identification of neural modules / Saul Sternberg -- The new interface of brain, mind, and machine : will the emergent whole be greater than the sum of the parts? / Chris Berka ... [et al.] -- The interaction of sleep and memory / Jeffrey M. Ellenbogen -- Attention, selection for action, error processing, and safety / Magdalena Fafrowicz and Tadeusz Marek -- Activity theory : comparative analysis of Eastern and Western approaches / Waldemar Karwowski, Gregory Z. Bedney, and Olexiy Y. Chebykin -- Discourse in activity / Harry Daniels -- Movements of the cane prior to locomotion judgments : the informer fallacy and the training fallacy versus the role of exploration / Gregory Burton and Jennifer Cyr -- Emotional intelligence : a novel approach to operationalizing the construct / E.L. Nosenko -- Emotional regulation of the learning process / Olexiy Y. Chebykin and S.D. Maksymenko -- Emotional resources of the professional trainer / G.V. Lozhkin -- Good judgment : the intersection of intelligence and personality / Robert Hogan, Joyce Hogan and Paul Barrett -- Relational self in action : relationships and behavior / Susan E. Cross and Kari A. Terzino.
  • 2008 CRCnetBASE
    Dul, Jan; Weerdmeester, B. A.
    Posture and movement -- Information and operation -- Environmental factors -- Work organization jobs and tasks -- The ergonomic approach -- Sources of additional information.
  • 2009 ScienceDirect
    Lanza, R. P.
    Introduction to stem cells -- Basic biology/mechanisms -- Tissue and organ development -- Methods -- Applications -- Regulation and ethics.
  • 2008
    Astolfi, Laura; Babiloni, Fabio.
  • 2011 Atypon
    Frize, Monique.
    Increasingly, biomedical scientists and engineers are involved in projects, design, or research and development that involve humans or animals. The book presents general concepts on professionalism and the regulation of the profession of engineering, including a discussion on what is ethics and moral conduct, ethical theories and the codes of ethics that are most relevant for engineers. An ethical decision-making process is suggested. Other issues such as conflicts of interest, plagiarism, intellectual property, confidentiality, privacy, fraud, and corruption are presented. General guidelines, the process for obtaining ethics approval from ethics Review Boards,and the importance of obtaining informed consent from volunteers recruited for studies are presented. A discussion on research with animals is included. Ethical dilemmas focus on reproductive technologies, stem cells, cloning, genetic testing, and designer babies. The book includes a discussion on ethics and the technologies of body enhancement and of regeneration. The importance of assessing the impact of technology on people, society, and on our planet is stressed. Particular attention is given to nanotechnologies, the environment, and issues that pertain to developing countries. Ideas on gender, culture, and ethics focus on how research and access to medical services have, at times, been discriminatory towards women. The cultural aspects focus on organ transplantation in Japan, and a case study of an Aboriginal child in Canada; both examples show the impact that culture can have on how care is provided or accepted. The final section of the book discusses data collection and analysis and offers a guideline for honest reporting of results, avoiding fraud, or unethical approaches. The appendix presents a few case studies where fraud and/or unethical research have occurred.
  • 2011
    Segalova, Polina A.; Kenny, Thomas W.; Rao, K. T.; Sheppard, S.; Zarins, Christopher K.
    Abdominal aortic aneurysms (AAA's) are characterized by a permanent and irreversible enlargement of the abdominal aorta to at least 150 percent its expected normal size. Endovascular treatment of AAA's with endografts has gained tremendous popularity in the last decade, largely due to decreased perioperative mortality and faster recovery times, when compared to open surgical repair. Although endografts are an appealing treatment option for many patients, some device design and safety issues have yet to be addressed. One of the biggest problems with endografts is their tendency to shift their position in the patient anatomy over time. The forces that cause this shift and their relation to endograft design are not well understood. In addition, the degree of blood damage due to the insertion of an endograft into the abdominal aorta has not been quantified. The following studies were completed in order to investigate the issues described above. 1. Calculation of endograft displacement force in patient-specific device models. This study used electron-beam computed tomography (CT) image data to generate patient-specific anatomical models using novel segmentation techniques. The patient models were then virtually modeled to represent three different endograft designs, based on aortic stent-graft devices already available in the U.S. or currently in clinical trials. Computational Fluid Dynamics (CFD) simulations were run to characterize the hemodynamic factors for each patient and a total displacement force was calculated for each model. Results show that the location of the device bifurcation impacts the overall displacement force, with proximal bifurcation endograft designs generating a lesser force than distal bifurcation designs. 2. Characterization of blood damage due to endograft placement. Patient-specific computational models were created to represent endograft features that partially obstruct blood flow to the renal arteries, which is sometimes necessary to attain complete exclusion of the aneurysm after deploying the device. Findings show that the insertion of an endograft causes a two-fold increase in blood damage. However, the magnitude of blood damage is within acceptable safety standards. 3. Benchtop testing of red blood cell damage. A benchtop experimental setup was created to measure the damage to red blood cells under various flow conditions and flow obstructions. Samples were characterized at different time points using light scatter methods to determine cell volume and hemoglobin concentration. Results indicate that significant damage to red blood cells occurs only after prolonged exposure (> 103 seconds) to high shear (> 4000 dynes/cm2) conditions. In addition, the presence of flow obstructions creates red blood cell fragments, instead of destroying the cells entirely. Future directions for this work include additional CFD modeling of devices in more patients treated with different aortic stent graft designs to derive statistical significance relative to various design and anatomical features and extend the analysis to the evaluation of devices used for the treatment of thoracic aortic aneurysms (TAA's). Follow-up studies on device migration studies can also be completed in the cohort of patients where the endograft displacement forces were calculated. Further, blood damage models that incorporate the fragmentation of red blood cells can be developed.
  • 2006 CRCnetBASE
    Kroemer, K. H. E.
  • 2006 Springer
    Bungartz, H.-J; Schäfer, Michael.
  • 2010
    Julian, Timothy Ryan; Boehm, Alexandria; Canales, Robert A.; Leckie, Jim.
    This dissertation examines the factors that influence fomite-mediated (e.g., indirect contact) transmission of viral gastrointestinal and respiratory illness. Specifically, the dissertation investigates virus transfer between surfaces and virus recovery from surfaces, models human-fomites interactions to estimate exposure and infection risk, and elucidates causal links between microbial contamination and illness in child care centers. Indirect contact transmission refers to person-to-person transmission of disease via an intermediate fomite (e.g., inanimate object acting as a carrier of infectious disease). The role of indirect contact in disease spread is poorly understood in part because the transmission route of viral pathogens is often difficult to determine. Transmission of respiratory and gastrointestinal viruses can occur through multiple routes (e.g., direct contact, indirect contact, airborne, and common vehicle), and the relative contribution of each route to total disease burden is unclear. The first study in this dissertation examines virus transfer between skin and surfaces, a necessary step in fomite-mediated transmission of viral disease. In the study, transfer of virus between fingerpads and fomites is explored in a laboratory setting. Bacteriophage (fr, MS2, and PHIX174) are used as proxies for pathogenic virus, and over 650 unique transfer events are collected from 20 different volunteers. The study concludes that approximately one quarter (23%) of recoverable virus is readily transferred from a contaminated surface (e.g., a fomite) to an uncontaminated surface (e.g., a finger) on contact. Using the large data set, the direction of transfer (from fingerpads-to-fomite or fomite-to-fingerpad) and virus species are demonstrated to both significantly influence the fraction of virus transferred by approximately 2-5%. To investigate the relative importance of factors contributing to fomite-mediated transmission, a child's risk of illness from exposure to a contaminated fomite is modeled. Specifically, the model estimates a child's exposure to rotavirus using a stochastic-mechanistic framework. Simulations of a child's contacts with the fomite include intermittent fomite-mouth, hand-mouth, and hand-fomite contacts based on activities of a typical child under six years of age. In addition to frequency of contact data, parameters estimated for use in the model include virus concentration on surface; virus inactivation rates on hands and the fomite; virus transfer between hands, fomite, and the child's mouth; and the surface area of objects and hands in contact. From the model, we conclude that a child's median ingested dose from interacting with a rotavirus-contaminated ball ranges from 2 to 1,000 virus over a period of one hour, with a median value of 42 virus. These results were heavily influenced by selected values of model parameters, most notably, the concentration of rotavirus on fomite, frequency of fomite-mouth contacts, frequency of hand-mouth contacts, and virus transferred from fomite to mouth. The model demonstrated that mouthing of fomite is the primary exposure route, with hand mouthing contributions accounting for less than one-fifth of the child's dose over the first 10 minutes of interaction. Based on the findings from the model that concentration of virus on a fomite influences a child's risk of illness, we investigate methods to recover virus from fomites. In a literature review and subsequent meta analysis, we demonstrate that the outcome currently used to describe virus contamination, positivity rate, is biased by the authors' selected sampling methods. We follow up, in the laboratory, with a comparison of the identified methods and demonstrate that polyester-tipped swabs prewetted in 1/4-strength Ringer's solution or saline solution is the most efficient sampling method for virus recovery tested. The recommended method is compatible with plaque assay and quantitative reverse-transcription polymerase chain reaction, two techniques used to quantify virus. The link between hand / fomite contamination and infection risk was explored in a field study at two child care centers over four months. Both respiratory and gastrointestinal disease incidence were tracked daily, while hand and environmental surface contamination were monitored weekly between February 2009 and June 2009. Microbial contamination was determined using quantitative densities of fecal indicator bacteria (e.g. Escherichia coli, enterococci, and fecal coliform) on hands and fomites as well as presence/absence of viral pathogens (e.g. enterovirus and norovirus). Health was monitored daily by childcare staff, who tracked absences, illness-related absences, and symptomatic respiratory and gastrointestinal illness. The resultant data suggests that increases in microbial contamination led to increases in symptomatic respiratory illness four to six days later, in agreement with typical incubation periods for respiratory illness. Similarly, respiratory illness led to increases in microbial contamination on hands during presentation of symptoms, and on fomites in the following three days.
  • 2008 CRCnetBASE
    Harris, Gerald F.; Marks, Richard M.; Smith, Peter A.
  • 2012 Atypon
    Cabral, Thanh M.; Rangayyan, Rangaraj M.
    Fractal analysis is useful in digital image processing for the characterization of shape roughness and gray-scale texture or complexity. Breast masses present shape and gray-scale characteristics in mammograms that vary between benign masses and malignant tumors. This book demonstrates the use of fractal analysis to classify breast masses as benign masses or malignant tumors based on the irregularity exhibited in their contours and the gray-scale variability exhibited in their mammographic images. A few different approaches are described to estimate the fractal dimension (FD) of the contour of a mass, including the ruler method, box-counting method, and the power spectral analysis (PSA) method. Procedures are also described for the estimation of the FD of the gray-scale image of a mass using the blanket method and the PSA method.
  • 2011 Springer
    Hernandez, Carlos.
    Introduction: From Brains to the Machines of the Future / Ricardo Sanz, Carlos Hernández and Jaime Gómez-Ramirez -- Emergent Feature Sensitivity in a Model of the Auditory Thalamocortical System / Martin Coath, Robert Mill, Susan L. Denham and Thomas Wennekers -- STDP Pattern Onset Learning Depends on Background Activity / James Humble, Steve Furber, Susan L. Denham and Thomas Wennekers -- Emergence of Small-World Structure in Networks of Spiking Neurons Through STDP Plasticity / Gleb Basalyga, Pablo M. Gleiser and Thomas Wennekers -- Coupling BCM and Neural Fields for the Emergence of Self-organization Consensus / Mathieu Lefort, Yann Boniface and Bernard Girau -- Alpha and Theta Rhythm Abnormality in Alzheimer's Disease: A Study Using a Computational Model / Basabdatta Sen Bhattacharya, Damien Coyle and Liam P. Maguire -- Oscillatory Neural Network for Image Segmentation with Biased Competition for Attention / Tapani Raiko and Harri Valpola -- Internal Simulation of Perceptions and Actions / Magnus Johnsson and David Gil -- Building Neurocognitive Networks with a Distributed Functional Architecture / Marmaduke Woodman, Dionysios Perdikis, Ajay S. Pillai, Silke Dodel and Raoul Huys, et al. -- Reverse Engineering for Biologically Inspired Cognitive Architectures: A Critical Analysis / Andreas Schierwagen -- Competition in High Dimensional Spaces Using a Sparse Approximation of Neural Fields / Jean-Charles Quinton, Bernard Girau and Mathieu Lefort -- Informational Theories of Consciousness: A Review and Extension / Igor Aleksander and David Gamez -- Hippocampal Categories: A Mathematical Foundation for Navigation and Memory / Jaime Gómez-Ramirez and Ricardo Sanz -- The Role of Feedback in a Hierarchical Model of Object Perception / Salvador Dura-Bernal, Thomas Wennekers and Susan L. Denham -- Machine Free Will: Is Free Will a Necessary Ingredient of Machine Consciousness? / Riccardo Manzotti -- Natural Evolution of Neural Support Vector Machines / Magnus Jändel -- Self-conscious Robotic System Design Process - From Analysis to Implementation / Antonio Chella, Massimo Cossentino and Valeria Seidita -- Simulating Visual Qualia in the CERA-CRANIUM Cognitive Architecture / Raúl Arrabales, Agapito Ledezma and Araceli Sanchis -- The Ouroboros Model, Selected Facets / Knud Thomsen.
    Also available: Print – 2011
  • 2012 Springer
    Maurits, Natasha M.
    1. Introduction -- 2. Carpal Tunnel Syndrome, Electroneurography, Electromyography, and Statistics -- 3. Tremor, Polymyography, and Spectral Analysis -- 4. Epilepsia, Electroencephalography, Filtering, and Feature Extraction -- 5. Multiple Sclerosis, Evoked Potentials, and Enhancing Signal-to-Noise Ratio -- 6. Cortical Myoclonus, EEG-EMG, Back-Averaging, and Coherence Analysis -- 7. Psychogenic Movement Disorders, Bereitschaftspotential, and Event-Related Potentials -- 8. Brain Tumor, Preoperative Function Localization, and Source Localization -- 9. Neuromuscular Diseases, Ultrasound, and Image Analysis -- 10. Cerebrovascular Disease, Ultrasound, and Hemodynamical Flow Parameters -- 11. Spinal Dysfunction, Transcranial Magnetic Stimulation, and Motor Evoked Potentials.
  • 2011
    Durand, Remy; Deisseroth, Karl; Graves, Edward; Shen, Kang.
    Functional brain imaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have emerged over the last several decades as powerful methods for understanding brain function and neuropsychiatric disorders. However, due to an inability to precisely and distinctly control the heterogeneous population of circuit elements in the brain, understanding the fundamental physiological mechanisms of these imaging modalities and realizing their potential for functional brain mapping has been limited. Optogenetics is a novel technique that allows for cell-type specific, reversible focal control within the mammalian brain with millisecond-timescale precision. In this thesis, I have utilized the unique cell-type specific neuromodulatory capacity of optogenetics to demonstrate and characterize, for the first time, the effect of direct stimulation of a subclass of excitatory neurons on the in vivo functional hemodynamic response of a rodent brain as measured with functional magnetic resonance imaging (fMRI). I have then used this technique, which we have called ofMRI, to perform large-scale functional mapping of distinct neural circuits that are specified by cell-type, cell-body location, and projection topology. To complement ofMRI studies, I have also developed the use of PET imaging and the radiotracer [18F]-fluorodeoxyglucose (FDG) to further characterize the metabolic and hemodynamic response resulting from activation of genetically-specified neurons in the mammalian brain. Additionally, I have constructed an automated, parallelized all-optical ex vivo system for modulation and recording of distinct neural circuits relevant to neuropsychiatric disorders using voltage sensitive dye imaging (VSDI). Combining the highly specific and rapid control of optogenetics with the biological process sensitivity of PET, the spatial and temporal resolution of BOLD fMRI, and the neural circuit analysis capabilities of optical imaging has the potential to vastly increase our understanding of the roles of neural circuits in both normal and diseased brain states.
  • 2007 Springer
    Knudson, Duane V.
  • 2010 Atypon
    Miller, Gerald E.
    Transport processes represents important life sustaining elements in all humans. These include mass transfer processes, including gas exchange in the lungs, transport across capillaries and alveoli, transport across the kidneys, and transport across cell membranes. These mass transfer processes affect how oxygen and carbon dioxide are exchanged in your bloodstream, how metabolic waste products are removed from your blood, how nutrients are transported to tissues, and how all cells function throughout the body. A discussion of kidney dialysis and gas exchange mechanisms is included. Another element in biomedical transport processes is that of momentum transport and fluid flow. This describes how blood is propelled from the heart and throughout the cardiovascular system, how blood elements affect the body, including gas exchange, infection control, clotting of blood, and blood flow resistance, which affects cardiac work. A discussion of the measurement of the blood resistance to flow (viscosity), blood flow, and pressure is also included. A third element in transport processes in the human body is that of heat transfer, including heat transfer inside the body towards the periphery as well as heat transfer from the body to the environment. A discussion of temperature measurements and body protection in extreme heat conditions is also included.
  • 2009 Springer
    Handschel, Jörg; Meyer, Thomas; Meyer, Ulrich; Wiesmann, Hans Peter.
  • 2006 Springer
    Nolta, Jan A.
    Also available: Print – 2006
  • 2002 CRCnetBASE
    Burrows, Beth Elpern; Letourneau, Deborah Kay.
  • 2014 Springer
    Marko-Varga, György A.
    This book offers a valuable resource that allows students, researchers, educators and the general public to learn about proteomics and genomics. Chromosomes form the basis for our genetic heritage and are the code for protein synthesis. The Human Genome Map was presented in 2002, and the Proteome Sequence Map is currently being created by a global consortia initiative. Proteome and genome building blocks already form the basis of scientific research areas and shape major areas of the pharmaceutical and biomedical industries. The book provides background information on and our current understanding of these gene and protein areas, and explains in detail how cutting-edge science is using these resources to develop new medicines and new diagnostics for patient treatment and care. The book will benefit all students and researchers who need a good understanding of genomics and proteomics within the clinical field. Its content is also suitable for a broad readership, including those not specialized in this field. Dr. Marko-Varga is head of Div. Clinical Protein Science & Imaging at the Biomedical Center, Dept. of Measurement Technology and Industrial Electrical Engineering, Lund University. He's also Professor at the 1st Department of Surgery, Tokyo Medical University, Tokyo, Japan.
  • 2011
    Gaster, Richard Samuel; Liao, Joseph; Wang, Shan X.; Yock, Paul G.
    Nanotechnology has the unique capability of manipulating and sensing matter at the molecular scale with unprecedented speed, sensitivity, and throughput. The medical application of nanotechnology, nanomedicine, has leveraged nanoscience tools for the advancement of medical diagnostics, therapy, and basic science research. In this work, arrays of magnetically responsive nanosensors, originally developed for use as read heads in computer hard disk drives, have been utilized to achieve in-depth proteomic studies for the advancement of medical diagnostics and therapy. In particular, this dissertation will focus on the following four topics of applying magnetic nanotechnology to science and medicine. First, the application of magnetic nanosensor arrays to early cancer diagnostics and monitoring response to chemotherapy. The utility of magnetic nanosensors as a molecular diagnostics tool capable of profiling a patient's disease state and leveraging a patient's unique molecular signature will be demonstrated. Second, this report will discuss a novel mathematical model expressly developed to describe the kinetic interactions of magnetically labeled biomolecules binding to capture agents immobilized on a surface. Third, a novel autoassembly immunoassay capable of screening for antibody cross-reactivity in a high-density, high-fidelity, and rapid manner will be described. Finally, this report will address the utility of the autoassembly immunoassay in conjunction with a miniaturized magnetic nanosensor platform for point-of-care diagnostics in a cost-effective and easy-to-use (e.g. wash-free) process that can make a significant contribution to global health.
  • 2011
    Hall, Drew Alexander; Murmann, Boris; Wang, Shan X.; Wooley, Bruce A.
    Nanotechnology has had a transformative effect on medical diagnostics due to the influx of new sensing modalities and transducers. Magnetic nanotechnologies, in particular, have shown significant potential in several areas of nanomedicine such as imaging, therapeutics, and early disease detection. Giant magnetoresistive spin-valve (GMR SV) sensors, commonly used in hard disk drives, coupled with magnetic nanotags have shown great promise as biosensors. In this work, we present several custom designed circuit interface and readout systems tailored to specific application spaces and their unique needs. Taken together, we have demonstrated that innovative electronic circuits play an indispensable role in unlocking the tremendous potential of nanosensors in the biomedical arena. The first system was designed for ultrasensitive early cancer diagnostics and built using off-the-shelf components for an 8x8 array of GMR SV sensors. At the core of this design, we demonstrate a new circuit architecture based on a transimpedance amplifier (TIA) with a carrier suppression technique to reduce the dynamic range requirement and a multiplexing scheme to reduce the readout time. This system is capable of real-time, multiplex detection with a detection limit of 5 femtomolar (fM) and over 6 orders of linear dynamic range. The second system is a miniaturized, portable platform called the nanoLAB. Although there is a growing need for point-of-care (POC) testing for global health, the current options are bulky, slow, expensive, and often not sensitive. The nanoLAB addresses these needs and pushes the state of the art with sensitive 8-plex detection using a wash-free assay that can be run by anyone, anywhere. This platform was tested and validated using human immunodeficiency virus (HIV) biomarkers with detection down to 50 fM in as little as 15 minutes. We also show how a GMR SV biosensor can be integrated into a continuous time sigma delta modulator. This proof-of-concept hybrid sigma delta modulator has a peak SNR of 99.3 dB and a dynamic range of over 92 dB in a 1 kHz bandwidth using the sensor as part of the first integrator. The carrier suppression and multiplexing concepts were also incorporated into the hybrid sigma delta modulator. Lastly, we conclude by describing an integrated platform for a large 16x16 array of GMR SV sensors implemented in a 0.18 [mu]m CMOS technology. Arranged like an imager chip, each of the 16 column level readout channels contains an analog front-end and an analog-to-digital converter. Each readout channel occupies less than 0.2 mm^2 of chip area and consumes 3.4 mW of power. This system is designed as a replacement for optical protein microarrays while being fully quantitative and providing real-time readout.
  • 2010 Atypon
    De Vico Fallani, Fabrizio; Babiloni, Fabio.
  • 2003 CRCnetBASE
  • 2007 CRCnetBASE
    Barnes, Frank S.; Greenebaum, Ben.
    Introduction -- 1. Environmental and Occupationally Encountered Electromagnetic Fields / Kjell Hansson Mild and Ben Greenebaum -- 2. Endogenous Electric Fields in Animals / Richard Nuccitelli -- 3. Dielectric Properties of Biological Materials / Camelia Gabriel -- 4. Magnetic Properties of Biological Material / Jon Dobson -- 5. Interaction of Direct Current and Extremely Low-Frequency / Electric Fields with Biological Materials and Systems / Frank S. Barnes -- 6. Magnetic Field Effects on Free Radical Reactions in Biology / Stefan Engström -- 7. Signals, Noise, and Thresholds / James C. Weaver and Martin Bier -- 8. Biological Effects of Static Magnetic Fields / Shoogo Ueno and Tsukasa Shigemitsu -- 9. The Ion Cyclotron Resonance Hypothesis / A.R. Liboff -- 10. Computational Methods for Predicting Field Intensity and Temperature Change / James C. Lin and Paolo Bernardi -- 11. Experimental EMF Exposure Assessment / Sven Kühn and Niels Kuster -- 12. Electromagnetic Imaging of Biological Systems / William T. Joines, Qing H. Liu, and Gary Ybarra.
  • 2008 Springer
    Flynn, Patrick J.; Jain, Anil K.; Ross, Arun A.
  • 2005 CRCnetBASE
    Stanton, Neville.
  • 2012 CRCnetBASE
    Khang, Gilson.
    Pt. 1. Introduction -- pt. 2. Ceramic and metal scaffold -- pt. 3. Intelligent hydrogel -- pt. 4. Electrospinning nanofiber -- pt. 5. Novel biomaterials for scaffold -- pt. 6. Novel fabrication methods for scaffold -- pt. 7. Scaffold for target organ.
  • 2012 Springer
    Jain, K. K.
    Nanotechnologies -- Nanotechnologies for Basic Research Relevant to Medicine -- Nanomolecular Diagnostics -- Nanopharmaceuticals -- Role of Nanotechnology in Biological Therapies -- Nanodevices and Techniques for Clinical Applications -- Nanooncology -- Nanoneurology -- Nanocardiology -- Nanopulmonology -- Nanoorthopedics -- Nano-ophthalmology -- Nanomicrobiology -- Miscellaneous Healthcare Applications of Nanobiotechnology -- Nanobiotechnology and Personalized Medicine -- Nanotoxicology -- Ethical and Regulatory Aspects of Nanomedicine -- Research and Future of Nanomedicine.
  • 2008
    Jain, K. K.
    PrintStatus: Not Checked OutLane Catalog Record
  • Click LINK above for Print location/circulation status.
    2003 CRCnetBASE
    Goddard, William A.
    Enabling technologies for molecular nanosystems -- Solution-phase chemistry -- Dynamics of brownian assembly -- Molecular systems by brownian assembly -- Large secondary bonded systems -- Protein and DNA engineering.
  • 2003 CRCnetBASE
    Finn, Warren E.; LoPresti, Peter G.
  • 2009 CRCnetBASE
    Tuchin, V. V.
    "This handbook presents methods that improve the accuracy in glucose prediction based on infrared absorption spectroscopy, recent studies on the influence of acute hyperglycemia on cerebral blood flow, and the correlation between diabetes and the thermo-optical response of human skin. It examines skin glucose monitoring by near-infrared spectroscopy (NIR), fluorescence-based glucose biosensors, and a photonic crystal contact lens sensor. The contributors also explore problems of polarimetric glucose sensing in transparent and turbid tissues as well as offer a high-resolution optical technique for noninvasive, continuous, and accurate blood glucose monitoring and glucose diffusion measurement."--BOOK JACKET.
  • 2010 CRCnetBASE
    Tuchin, V. V.
  • 2010 CRCnetBASE
    Splinter, Robert.
  • 2013 Atypon
    Frize, Monique.
    The first chapter describes the health care delivery systems in Canada and in the U.S. This is followed by examples of various approaches used to measure physiological variables in humans, either for the purpose of diagnosis or monitoring potential disease conditions; a brief description of sensor technologies is included. The function and role of the clinical engineer in managing medical technologies in industrialized and in developing countries are presented. This is followed by a chapter on patient safety (mainly electrical safety and electromagnetic interference); it includes a section on how to minimize liability and how develop a quality assurance program for technology management. The next chapter discusses applications of telemedicine, including technical, social, and ethical issues. The last chapter presents a discussion on the impact of technology on health care and the technology assessment process.
  • 2013 Atypon
    Frize, Monique.
    Chapter 7 presents some statistics on the occurrence of medical errors and adverse events, and includes some technological solutions. A chapter on electronic medical records follows. The knowledge management process divided into four steps is described; this includes a discussion on data acquisition, storage, and retrieval. The next two chapters discuss the other three steps of the knowledge management process (knowledge discovery, knowledge translation, knowledge integration and sharing). The last chapter briefly discusses usability studies and clinical trials. The two parts consolidate material that supports courses on technology development and management issues in health care institutions. It can be useful for anyone involved in design, development, or research, whether in industry, hospitals, or government.
  • 2013 Springer
    Iaizzo, Paul A.
    Anatomy, Physiology, Congenital Defects, and Disease -- The Anatomy and Function of the Atrioventricular Valves / Michael G. Bateman, Jason L. Quill, Alexander J. Hill, Paul A. Iaizzo -- The Anatomy and Function of the Semilunar Valves / Michael G. Bateman, Jason L. Quill, Alexander J. Hill, Paul A. Iaizzo -- Congenital Heart Defects That Include Cardiac Valve Abnormalities / Roosevelt Bryant III -- Acquired Valve Disease and Processes / Cindy M. Martin -- Valve Repair and Replacement -- History of Heart Valve Repair / Lauren B. Kwasny, Richard W. Bianco, Luis H. Toledo-Pereyra, -- Heart Valve Disease / Ranjit John, Kenneth Liao -- Advanced 3D Imaging and Transcatheter Valve Repair/Implantation / Paul Schoenhagen, Andrew C. Y. To -- Transcatheter Mitral Repair and Replacement / Jason L. Quill, Ana R. Menk, Gilbert H. L. Tang -- Percutaneous Pulmonary Valve Implantation: The First Transcatheter Valve / Silvia Schievano, Andrew M. Taylor, Philipp Bonhoeffer -- Transcatheter Aortic Valve Implantation / Nicolo Piazza, Darren Mylotte -- Tissue-Engineered Heart Valves / Jillian B. Schmidt, Robert T. Tranquillo -- Testing and Regulatory Issues -- In Vitro Testing of Heart Valve Substitutes / Timothy A. Kelley, Sal Marquez, Carl F. Popelar -- Numerical Methods for Design and Evaluation of Prosthetic Heart Valves / Michael J. Schendel, Carl F. Popelar -- Animal Models for Cardiac Valve Research / Sarah E. Ahlberg, Michael G. Bateman, Michael D. Eggen, Jason L. Quill -- The Use of Isolated Heart Models and Anatomic Specimens as Means to Enhance the Design and Testing of Cardiac Valve Therapies / Michael G. Bateman, Alexander J. Hill, Jason L. Quill, Michael D. Eggen -- Successful Development and Regulatory Approval of Replacement Cardiac Valves / Stephen A. Howard, Michael G. Bateman, Timothy G. Laske, Paul A. Iaizzo -- Clinical Trial Requirements for Cardiac Valves / Jenna C. Iaizzo, Anna T. F. Lovas.
  • 2011
    Suh, Ga Young; Lele, Sanjiva K.; Taylor, Charles A.; Tsao, Philip.
    Hemodynamic conditions are hypothesized to affect the initiation, growth, and rupture of abdominal aortic aneurysms (AAAs), a vascular disease characterized by progressive wall degradation and enlargement of the abdominal aorta. We hypothesized that the progression of AAA may be slowed by altering the hemodynamics in the abdominal aorta through exercise. The aim of the first study in this thesis was to use magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) to quantify flow stagnation and recirculation in AAAs by computing particle residence time (PRT). Specifically, we used gadolinium-enhanced MR angiography (MRA) to obtain images of the vessel lumens, which were used to generate subject-specific models. Phase-contrast MRI was used to measure blood flow at supraceliac and infrarenal locations to prescribe physiologic boundary conditions. CFD was used to simulate pulsatile flow, and PRT, particle residence index, and particle half-life of PRT in the aneurysms were computed. We observed significant regional differences of PRT in the aneurysms with localized patterns that differed depending on aneurysm geometry and infrarenal flow. A saccular aneurysm with the lowest mean infrarenal flow demonstrated the slowest particle clearance. In addition, improvements in particle clearance were observed with increase of mean infrarenal flow. This result motivated the next study to quantify the effect of augmentation of mean infrarenal flow during exercise on reducing chronic flow stasis that may promote increased mural thrombus burden, degradation of the vessel wall, and aneurysm growth. In the second study, we investigated three levels of activity, rest, mild and moderate intensities of lower-limb exercise to quantify the effect of exercise on hemodynamic conditions in AAA subjects. We measured the abdominal aortic blood flow at rest and during dynamic exercise, and quantified mean wall shear stress (MWSS), oscillatory shear index (OSI), and PRT. We observed that an increase in the level of activity correlated with an increase of MWSS and a decrease of OSI at three locations in the abdominal aorta, and these changes were most significant below the renal arteries. As the level of activity increased, PRT in the aneurysm was significantly decreased: 50% of particles were cleared out of AAAs within 1.36 ± 0.43, 0.34 ± 0.10, and 0.22 ± 0.06 s at rest, mild exercise and moderate exercise levels, respectively. Most of the reduction of PRT occurred from rest to the mild exercise level suggesting that mild exercise may be sufficient to reduce flow stasis in AAAs. The third study aimed to correlate hemodynamic characteristics of AAA with its progression, and quantify morphologic changes of aneurysm from study intake to 1.5-3.5-year follow-up of subjects randomized to usual activity or exercise training cohort. We acquired MRA of 16 subjects, and mid-aneurysm wall content data of 12 subjects at each intake and follow-up visit. 3D lumen models were built based on each intake and follow-up MRAs of six subjects. We observed morphologic changes of aneurysm lumen from intake to follow-up MRA of 11 subjects which exhibited local smoothing, shrinkage or expansion. We observed thickening of thrombus burden from follow-up wall content image of seven subjects whose aneurysm lumen was eventually narrowed. Based on 3D model comparison between intake and follow-up, and the correlation of morphologic changes with wall content changes and PRT contour plots computed in the previous study, we suggest that the region of narrowed lumen induced by thrombus buildup may be consistent with the region of long PRT. As a future work, we will extend our research in conjunction with CT data to quantify the changes of aneurysm wall, and increase the number of subjects to find more conclusive results.
  • 2010 Springer
    Cobb, Stuart; Cutsuridis, Vassilis; Graham, Bruce; Vida, Imre.
  • 2014 Springer
    Hillmann, Dierck.
    Holoscopy is a new tomographic imaging modality that combines techniques of digital holography with Fourier-domain optical coherence tomography (FD-OCT). Dierck Hillmann gives a theoretical introduction to the mathematics and physics of holoscopy and develops an efficient numerical reconstruction procedure. Compared to FD-OCT, holoscopy provides unique advantages by enabling tomographic imaging without a limited depth of focus, but results in an increased numerical cost for reconstruction. In further chapters, the author introduces techniques for FD-OCT that are relevant to holoscopy as well. He demonstrates and compares numerical reconstruction methods for FD-OCT and shows how motion and dispersion artifacts in FD-OCT can be numerically compensated. Contents Theoretical Introduction to Optical Coherence Tomography and Digital Holography FD-OCT Signal Processing Using the Non-Equispaced Fast Fourier Transform Motion and Dispersion Correction in FD-OCT Holoscopy Target Groups Academics and practitioners in the fields of computer science, optical coherence tomography, digital holography, and medical imaging. The Author Dierck Hillmann received his doctoral degree in the group of Gereon Hüttmann at the Institute of Biomedical Optics in Lübeck and is currently working for a leading company in the fields of science and photonics. The Editor The series Aktuelle Forschung Medizintechnik is edited by Thorsten M. Buzug.
  • 2009 Springer
    Masters, J. R. W.; Palsson, Bernhard.
    1. Neural progenitors / Dustin R. Wakeman ... [et al.] -- 2. Multipotent stromal cells (hMSCs) / Margaret Wolfe ... [et al.] -- 3. Endothelium / Sangmo Kwon, Takayuki Asahara -- 4. Lung / Rabindra Tirouvanziam, Megha Makam, Bruno Péault -- 5. Eye / Maria Notara ... [et al.] -- 6. Colon / F. Iovino ... [et al.] -- 7. Spermatogonia / Makoto C. Nagano, Jonathan R. Yeh, Khaled Zohni -- 8. Hair follicle pluripotent stem (hfPS) cells / Robert M. Hoffman -- 9. Pancreas / Fang-Xu Jiang, Grant Morahan -- 10. Prostate / C. Foley ... [et al.].
  • 2003 CRCnetBASE
    Boyce, P. R.
  • 2012 Springer
    Schildmann, Jan.
    Part 1. Historical and Socio-Cultural Contexts in Medical Research / British Responses to Nazi Medical War Crimes / Fiona McClenaghan -- History and its Relevance in the Development and Teaching of Research Ethics / Rael D. Strous -- Human Embryo Research and Islamic Bioethics: A View from Iran / Mansooreh Saniei -- From Farming to Pharming: Transcending of Bodily Existence as a Question of Medical Ethics in an Intercultural Context / Axel Siegemund -- Introduction / Jan Schildmann, Verena Sandow, Oliver Rauprich and Jochen Vollmann -- Part 2. Considerations on Ethical and Legal Regulations for Medical Research / Rethinking the Therapeutic Obligation in Clinical Research / Nunziata Comoretto -- Biomedical Research in Developing Countries and International Human Rights Law / Ilja R. Pavone -- Research Involving Human Subjects and Human Biological Material from a European Patent Law Perspective. Autonomy, Commodification, Patentability / Tomasz Zimny -- The Development and Validation of a Guide for Peruvian Research Ethics Committees to Assist in the Review of Ethical-Scientific Aspects of Clinical Trials / Susy Olave Quispe, Duilio Fuentes Delgado, Gabriela Minaya Martínez, Rosa Surco Ibarra and Martín Yagui Moscoso, et al. -- Part 3. Conflicts in Medical Research / Conflicts of Interest in Medical Research: What can Ethics Contribute? / Verena Sandow, Jan Schildmann and Jochen Vollmann -- Research Ethics in Genomics Research: Feedback of Individual Genetic Data to Research Participants / Annelien L. Bredenoord and Johannes J. M. van Delden -- Regulating "Higher Risk, No Direct Benefit" Studies with Children: Challenging the US Federal Regulations / Anna E. Westra, Jan M. Wit, Rám N. Sukhai and Inez D. de Beaufort -- Part 4. New Developments in Medical Research and Ethical Implications / A Paradigm Change in Research Ethics / Rieke van der Graaf and Johannes J. M. van Delden -- Translation of Cancer Molecular Biomarkers: Ethical and Epistemological Issues / Flavio D'Abramo and Cecilia Guastadisegni -- Rethinking the Ethics of Human Biomedical Non-Interventional Research / Kristi L{tilde}ouk.
  • 2013 CRCnetBASE
    Abdul Rahim, Nur Aida; Yu, Hanry.
    "This book covers the full range of available imaging modalities and optical methods used to help evaluate material and biological behavior. It also highlights a wide range of optical and biological applications. Each chapter in the text describes a specific application and discusses relevant instrumentation, governing physical principles, data processing procedures, as well as advantages and disadvantages of each modality. Following a broad introduction to key topics, the main chapters are divided between in vitro and in vivo applications. The final section focuses on methods for data processing and analysis"--Provided by publisher.
  • 2015 Springer
    Ekdahl, Kristina N.; Lambris, J. D.; Nilsson, Bo; Ricklin, Daniel.
    1. Thromboinflammation in therapeutic medicine -- 2. Complement interactions with blood cells, endothelial cells and microvesicles in thrombotic and inflammatory conditions -- 3. Role of complement on broken surfaces after trauma -- 4. Complement involvement in periodontitis: molecular mechanisms and rational therapeutic approaches -- 5. The lectin pathway of complement and biocompatibility -- 6. Foreign body reaction to subcutaneous implants -- 7. Molecular characterization of macrophage-biomaterial interactions -- 8. Heparan sulfate proteoglycan metabolism and the fate of grafted tissues -- 9. Xenotransplantation of cells, tissues, organs and the Greman research foundation Transregio Collaborative Research Centre 127 -- 10. Macroencapsulated pig islets correct induced diabetes in primates up to 6 months -- 11. Regulation of instant blood mediated inflammatory reaction (IBMIR) in pancreatic islet xeno-transplantation: points for therapeutic interventions -- 12. Cell surface engineering for reguation of immune reactions in cell therapy -- 13. Complement interception across humoral incompatibility in solid organ transplantation: a clinical perspective -- Index.
    Also available: Print – 2015
  • 2013 Springer
    Korpas, David.
    History and development of pacing -- Basic principles of cardiac pacemaker technology -- Heart anatomy and physiology -- Pharmacological treatment of cardiac rhythm disorders -- Pacing modes -- Indications for implantable system treatment -- Leads -- Pacing systems -- Pacemaker timing -- Implantable cardioverter-defibrillators -- Cardiac resynchronization therapy -- Implantation, explantation, and replacement of devices and leads -- Patient follow-up -- Electromagnetic compatibility and technical requirements.
  • 2010
    O'Sullivan, Thomas Daniel; Gambhir, Sanjiv Sam; Harris, J. S.; Levi, Ofer.
    Molecular imaging is an established technique used to visualize and quantify functional information about biological processes in living systems. In vivo fluorescence imaging, in particular, is a molecular imaging technique capable of quantitatively imaging one or more fluorophores at high spatial and temporal resolution with high sensitivity, either at microscopic or macroscopic (whole-body) scales. While current fluorescent imaging technologies have led to key advances in the understanding of biology and biochemistry, there are limitations. Modern in vivo fluorescence imagers are bulky, and typically take snapshots, and only sample discrete points of continuous, dynamic processes. In order to overcome these obstacles and enable long-term, continuous fluorescence imaging in live animals, we have miniaturized the components of the optical imaging system, allowing for direct implantation. Miniature fluorescence sensors have been fabricated to match a particular fluorescent probe utilizing semiconductor processing technology and appropriate materials. We present the design and fabrication of a monolithically integrated semiconductor (GaAs-based) sensor for far-red to near infrared (NIR) in vivo fluorescence sensing. The sensor incorporates three basic components of a fluorescence system, including: a 675nm vertical-cavity surface-emitting laser (VCSEL) excitation source, a GaAs PIN photodiode, and a fluorescence emission filter. We have packaged the sensors in several integrated configurations, and developed readout mechanisms that include a system that can be implanted in small rodents. We have utilized this device to demonstrate that in vivo fluorescence imaging is possible with miniaturized, un-cooled semiconductor devices, including a demonstration of sensing in a freely-moving rodent. Such miniaturized, implantable biomedical devices have the potential to accelerate pre-clinical research and revolutionize clinical care by providing an inexpensive means for diagnosis, monitoring disease progression, and evaluating long-term treatment efficacy. By integrating this implantable sensor with the appropriate read-out electronics and wireless telemetry, un-tethered operation can ultimately be achieved.
  • 2014 Springer
    Mankekar, Gauri.
    Hearing loss can vary in type ranging from conductive, mixed to sensorineural, as well as in degree from mild, moderate, severe to profound. There could also be multiple permutations and combinations like moderate mixed hearing loss or severe conductive hearing loss. In addition, the hearing loss could be unilateral or bilateral. While cochlear implants were devised for bilateral profound sensorineural hearing loss, various other devices have been invented for other types of hearing losses. Research continues to design a suitable implant which would amplify sound for patients who cannot be candidates for cochlear implants.
  • 2010
    Chen, Michael Quay; Kovacs, Gregory T. A.; Smolke, Christina D.; Wu, Joseph C.
    The limited ability of the human heart to regenerate has made myocardial infarction and heart failure debilitating conditions. Recently, an approach using pluri- or multi-potent stem cells to repair damaged heart tissue is being explored for its potential to regenerate tissue as a tailored, patient-specific treatment. However, the mechanisms of integration remain unclear, and many cardiac grafting procedures utilizing both embryonic and adult stem cells have been met with limited success. While current evidence suggests that grafts are likely viable in host myocardium, clinical studies have reported pro arrhythmic side-effects following transplantation, which arise from disrupted propagation patterns. These issues may be attributed to grafts lacking cardiac differentiation, or possessing conduction properties inconsistent with the host tissue. Consequently, understanding the role of the electrical environment throughout the engraftment process is necessary, but infeasible due to a lack of proper tools. Elucidating the electrical aspects of stem cell transplantation aims to ensure proper integration of the transplanted cells to prevent aberrant electrical pathways in the heart. In this work, a set of in vitro tools were developed to study the potential mechanisms underlying the risk of arrhythmia following stem cell transplantation. A planar microelectrode array was first used to investigate the possibility of conduction block if undifferentiated or non cardiomyocyte stem cells, such as mesenchymal stem cells, are used as grafts. Conduction in murine cardiomyocytes was purposely blocked by co-culture with non-conducting murine fibroblasts, and a novel mathematical transform known as a co occurrence matrix was developed to quantitatively analyze the uniformity of conduction. The observed sensitivity of cardiomyocyte conduction illustrated the risk of grafting non-cardiomyocyte cell types despite any potential of differentiating into muscle-like cells. Unlike non-conducting fibroblasts, stem cell grafts are expected to electrically conduct if proper cardiac differentiation takes place. However, possible differences in the conduction properties of these grafts may still lead to arrhythmia. To perform a controlled study of such conduction mismatch, an in vitro co-culture system coupled to microelectrode arrays was developed. Spatially separated cultures representing the host and the graft were allowed to gradually merge above the microelectrode array, allowing the measurement of conduction throughout the integration process. Modeled host and graft cell populations were evaluated by analyzing the co occurrence matrix and conduction velocity for the quality and speed of conduction over time. Co cultures between murine cardiomyocytes (host) and murine skeletal myoblasts (graft) exhibited significant differences in conduction despite synchronous electrical activity. In contrast, conduction was well matched when the same host cells were co cultured with murine embryonic stem cells (mESC). A model using murine cardiomyocytes (host) and differentiating human embryonic stem cells (graft) allowed the characterization of conduction properties relevant to current trans-species animal models, and demonstrate the co-culture device as a screening platform for candidate graft cells. The limited region of the graft that supported conduction exhibited differences in the co-occurrence matrix as well as conduction velocity when compared to the host region. In an effort to improve the effects of conduction mismatch, both host and graft cell populations were electrically paced over the length of time the cultures remained viable (4-5 days). Although a difference between conduction velocities between host and graft was still observed, the overall uniformity of conduction improved in paced co-cultures, implying increased cardiac differentiation. A preliminary study of genomic changes due to paced mESCs resulted in a significant upregulation of several important cardiac genes and a significant downregulation of many embryonic genes. Further efforts are currently underway to examine gene expression with paced hESCs to optimize integration in the host-graft model, and ultimately to understand how the electrical environment influences stem cell transplantation.
  • 2012 Springer
    Trebše, Rihard.
    Part 1 -- Introduction / Rihard Trebše -- Joint Replacement: Historical Overview / Rihard Trebše, Anže Mihelič -- Biomaterials in Artificial Joint Replacements / Rihard Trebše -- The Definition of Prosthetic Joint Infections (PJI) / Rihard Trebše, Andrej Trampuž -- Classification of Prosthetic Joint Infections / Rihard Trebše, Anže Mihelič -- The Epidemiology of Total Joint Arthroplasty Infections / David J. Jaekel, Kevin L. Ong, Edmund C. Lau -- Septic Complications in Arthroplasty / Gerold Labek -- Perioperative Antibiotic Prophylaxis in Total Joint Arthroplasty / Nataša Faganeli -- Risk Factors for Prosthetic Joint Infections / René Mihalič, Matevž Topolovec -- Pathogenesis of Prosthetic Joint Infections / Rihard Trebše, Jurij Štalc -- Bacteria-Biomaterial Interactions / Antti Soininen, Emilia Kaivosoja, Jaime Esteban -- Biomaterial-Host Interactions in Aseptic and Septic Conditions / Jukka Pajarinen, Yuya Takakubo, Zygmunt Mackiewicz -- Influence of Wear Particles on Local and Systemic Immune System / Emmanuel Gibon, Stuart B. Goodman -- Diagnostic Evaluations / Rihard Trebše -- Synovial Fluid Cytology / René Mihalič, Dunja Terčič -- Histological Analysis of Periprosthetic Tissue for Detecting Prosthetic Joint Infection / Andrej Cör -- Microbiological Diagnosis of Prosthetic Joint Infection / Jaime Esteban, Concepción Pérez-Jorge, Ramón Pérez-Tanoira -- Microbiological Processing of Samples in the Investigation of Suspected Prosthetic Joint Infection / David G. Partridge, Rob Towsend -- Part 2 -- Molecular Diagnosis of Prosthetic Joint Infection / Jaime Esteban, Diana Molina-Manso, Gema del-Prado -- Current Treatment Strategies in Prosthetic Joint Infections / Rihard Trebše Total Ankle Replacement Infections / Michaela Maria Schneiderbauer -- Periprosthetic Infection Issues with Osseointegrated (OI) Implant Technology in Amputees / Catherine Loc-Carrillo, Alec C. Runyon, James Peter Beck -- The Algorithm for Diagnostic Evaluation and Treatment / Rihard Trebše, Andrej Trampuž -- Bone Grafts and Bone Graft Substitutes in Infected Arthroplasty / Martin Clauss, Thomas Ilchmann.
  • 2011
    Shluzas, Lauren Marie Aquino; Leifer, Larry J.; Linehan, John H.; Steinert, Ralf Martin; Sutton, Robert I.
    Through an inductive, multi-case analysis, this dissertation examines how design and development practices, involving physicians and medical device developers, influence the clinical and financial outcomes of early stage medical device companies. This research was motivated by an interest in understanding the role of physicians in the device development process, specifically in terms of how physician interaction influences the acceptance or rejection of new medical products. An analytic framework for case-based research was first developed based on exploratory interviews with leaders in the medical device field. Retrospective case studies were then conducted on eight entrepreneurial firms (four rival pairs) in the areas of pulse oximetry, robotic surgery, cardiac bypass surgery, and minimally invasive spine surgery. Primary data sources included interviews with engineers, physicians, and business executives from each company; product development data including device prototypes, regulatory clearance data, and intellectual property (IP); and clinical and financial outcomes data. Following the period of data collection, within-case and across-case analyses were performed. The interview data for each case was coded for design and development practices involving physician-developer interaction, using NVivo qualitative analysis software (QSR International, Version 8). Development practices were analyzed using logic models to examine causal relationships between practices, and product and company outcomes. Design and development practices were further examined and supported using a combination of qualitative and quantitative evidence. Based on the multi-case analysis, this dissertation provides an overview of physician-developer interaction characteristics throughout each phase of the medical device development process. This includes a description of the roles and responsibilities of physicians engaged in development efforts, and their corresponding team affiliations. The research also illustrates four key factors that contributed to medical device adoption for the cases studied. First, the data highlight that designing products under variable use conditions (i.e. with variable patient populations and physicians of varying skill levels), enabled firms to optimize products for widespread clinical use and to increase the predictability of product outcomes. Second, the study shows that product adoption relied on maximizing benefits for multiple product stakeholders, while minimizing required changes in physician behavior. The data further illustrate that total benefit to product stakeholders was influenced to the greatest degree by benefits afforded to hospitals and physicians, assuming patient benefit was greater than or equal to the standard of care. Third, the study highlights that managing perceptions toward product use through performance data positively influenced product adoption to a greater degree than did market demand or regulatory clearance. Fourth, rival explanations for outcomes, involving limited physician interaction, indicate that competitive advantages were achieved through maintaining dominant financial and intellectual property positions. From these findings, the Insight-Value-Perception (iVP) Model for user-centered medical device design was constructed. The model links design and development practices to outcomes, from a combination of consumer-oriented, technical, and financial perspectives. This research provides theoretical contributions to product development and user-centered design literature, and provides practical contributions for developers in the medical device field. A contribution to product development literature is made through documenting the combined benefits of maximizing product value for stakeholders while managing data-driven perceptions toward product use. For the field of user-centered design, this research captures the benefits of designing medical technology with and for a broad consortium of product end-users, as opposed to industry leaders alone. The research also documents the importance of identifying the often-conflicting needs of product stakeholders, and then optimizing devices to satisfy the needs of those with the greatest influence over product use and adoption. For medical device practitioners, this dissertation provides design, regulatory, and product-testing strategies shown to increase technology adoption across the eight cases studied. From this thesis, the author proposes future studies to inform policies and strategies for device manufacturers and the FDA, and to advance knowledge in the fields of user-centered design and product development.
  • 2012 Cambridge
    Bettinger, Christopher.
    Progress towards Melanin Integration in Bio-Inspired Devices. -- Bio Organic-Based Gate Dielectric Materials for Thin Film Transistors.
  • 2011
    Lin, Der-Song; Howe, Roger T.; Kenny, Thomas W.; Khuri-Yakub, Butrus T.
    Capacitive micromachined ultrasonic transducers (CMUTs), have been widely studied in academia and industry over the last decade. CMUTs provide many benefits over traditional piezoelectric transducers including improvement in performance through wide bandwidth, and ease of electronics integration, with the potential to batch fabricate very large 2D arrays with low-cost and high-yield. Though many aspects of CMUT technology have been studied over the years, packaging the CMUT into a fully practical system has not been thoroughly explored. Two important interfaces of packaging that this thesis explores are device encapsulation (the interface between CMUTs and patients) and full electronic integration of large scale 2D arrays (the interface between CMUTs and electronics). In the first part of the work, I investigate the requirements for the CMUT encapsulation. For medical usage, encapsulation is needed to electrically insulate the device, mechanically protect the device, and maintain transducer performance, especially the access of the ultrasound energy. While hermetic sealing can protect many other MEMS devices, CMUTs require mechanical interaction to a fluid, which makes fulfilling the previous criterion very challenging. The proposed solution is to use a viscoelastic material with the glass-transition-temperature lower than room temperature, such as Polydimethylsiloxane (PDMS), to preserve the CMUT static and dynamic performance. Experimental implementation of the encapsulated imaging CMUT arrays shows the device performance was maintained; 95 % of efficiency, 85% of the maximum output pressure, and 91% of the fractional bandwidth (FBW) can be preserved. A viscoelastic finite element model was also developed and shows the performance effects of the coating can be accurately predicted. Four designs, providing acoustic crosstalk suppression, flexible substrate, lens focusing, and blood flow monitoring using PDMS layer were also demonstrated. The second part of the work, presents contributions towards the electronic integration and packaging of large-area 2-D arrays. A very large 2D array is appealing for it can enable advanced novel imaging applications, such as a reconfigurable array, and a compression plate for breast cancer screening. With these goals in mind, I developed the first large-scale fully populated and integrated 2D CMUTs array with 32 by 192 elements. In this study, I demonstrate a flexible and reliable integration approach by successfully combining a simple UBM preparation technique and a CMUTs-interposer-ASICs sandwich design. The results show high shear strength of the UBM (26.5 g), 100% yield of the interconnections, and excellent CMUT resonance uniformity ([lowercase Sigma] = 0.02 MHz). As demonstrated, this allows for a large-scale assembly of a tile-able array by using an interposer. Interface engineering is crucial towards the development of CMUTs into a practical ultrasound system. With the advances in encapsulation technique with a viscoelastic polymer and the combination of the UBM technique to the TSV fabrication for electronics integration, a fully integrated CMUT system can be realized.
  • 2006
    Enderle, John D.; Farden, David Charles; Krause, Daniel J.
  • v. 1, 2006 CRCnetBASE
    Karwowski, Waldemar.
  • 2011
    VanDersarl, Jules John; Heilshorn, Sarah; Longaker, Michael T.; Melosh, Nicholas A.
    Cells communicate through direct contact and soluble chemical signals. Mimicking an extracellular environment requires controlling these signals at micron length scales. Integrated circuits make electronic control at these scales trivial, but fluidic control at these length scales requires very different principles. Standard microfluidic devices can finely control flowing fluids, but fluid flow affects cells in a myriad of ways. Alternatively, diffusion based chemical delivery methods tend to be crude, ill defined systems that offer very limited control. This thesis describes three distinctive platforms that combine the active spatial and temporal control of microfluidic systems with a delivery system that relies purely on diffusion. First, we detail a silicon based array of nanoreservoirs underneath the cell culture surface which are used to store and release bioactive molecules. These reservoirs are opened and closed with electrochemical dissolution and deposition at a narrow reservoir opening. Next, we describe an adaptation of traditional, elastomer based microfluidics. In these devices the cell culture area is separated from a microfluidic channel located directly underneath the chamber by a nanoporous membrane. The desirable microfluidic properties, including temporal and spatial control, are preserved, while fluidic flow over the cells is eliminated. Finally, we demonstrate a novel "nanostraw" culture surface, which is combined with the previous device to offer fluidic access directly to the cell cytosol, creating a powerful tool with implications for cell delivery and sampling. Additional work on probing the assembly of protein structures is also detailed. Clathrin 2-dimensional lattice assembly on lipid monolayers, serving as cell membrane mimics, was monitored and studied through surface rheological techniques. Rheological measurements elucidated important network properties, and the formation process was compared to various models for clathrin network assembly.
  • 2010
    Nikoozadeh, Amin; Howe, Roger T.; Khuri-Yakub, Butrus T.; Murmann, Boris; Oralkan, Ömer.
    Atrial fibrillation, the most common type of cardiac arrhythmia, now affects more than 2.2 million adults in the United States alone. Currently, electrophysiological interventions are performed under fluoroscopic guidance, which does not provide adequate soft-tissue resolution and exposes the patient and the operator to harmful ionizing radiation. Intracardiac echocardiography (ICE) provides real-time anatomical information that has proven valuable in reducing the fluoroscopy time and enhancing procedural success. This dissertation describes the design and implementation of two types of multi-functional, forward-looking ICE catheters developed using capacitive micromachined ultrasonic transducer (CMUT) technology: MicroLinear (ML) and Ring catheters. The ML catheter enables real-time, forward-looking 2D imaging using a 24-element, fine-pitch 1D CMUT phased array. The Ring catheter uses a 64-element, ring-shaped 2D CMUT array that enables real-time, forward-looking, volumetric imaging. Both of these catheters are equipped with custom-designed, front-end electronic circuits that are integrated with each transducer array at the catheter tip. The close integration of custom electronic circuits with the ML and Ring CMUT arrays improves the signal-to-noise ratio (SNR) in each case by 18 dB and 20dB, respectively. The integration process of the CMUT arrays with the electronics dice in the tight space available for full catheter construction shows 100% yield. The characterization of the fully-integrated CMUT arrays demonstrates excellent pulse-echo response with over 100% fractional bandwidth as well as surface transmit pressure levels in excess of 1 MPa (peak-to-peak). The first fully-functional 9F ML CMUT ICE catheter shows remarkable in vivo imaging performance using porcine animal models. A similar in vivo imaging experiment with the first fully-functional 12F Ring CMUT ICE catheter proves very promising. The volumetric imaging capability of the Ring ICE catheter and the versatility offered by its inner lumen make it an attractive interventional device. This dissertation also introduces a novel CMUT structure, called PCMUT. The preliminary simulation and experimental verification of the PCMUT structure show that it is possible to fabricate CMUTs that exhibit non-flexural piston-like plate motion with a significantly improved volume displacement and fill-factor.
  • 2011 Springer
    Prokop, Aleš.
  • 2014 Springer
    Jolesz, Ferenc A.
    Image-guided therapy (IGT) uses imaging to improve the localization and targeting of diseased tissue and to monitor and control treatments. During the past decade, image-guided surgeries and image-guided minimally invasive interventions have emerged as advances that can be used in place of traditional invasive approaches. Advanced imaging technologies such as magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET) entered into operating rooms and interventional suites to complement already-available routine imaging devices like X-ray and ultrasound. At the same time, navigational tools, computer-assisted surgery devices, and image-guided robots also became part of the revolution in interventional radiology suites and the operating room. Intraoperative Imaging and Image-Guided Therapy explores the fundamental, technical, and clinical aspects of state-of the-art image-guided therapies. It presents the basic concepts of image guidance, the technologies involved in therapy delivery, and the special requirements for the design and construction of image-guided operating rooms and interventional suites. It also covers future developments such as molecular imaging-guided surgeries and novel innovative therapies like MRI-guided focused ultrasound surgery. IGT is a multidisciplinary and multimodality field in which teams of physicians, nurses, and other professionals, such as physicists, engineers, and computer scientists, collaborate in performing these interventions, an approach that is reflected in the organization of the book. Contributing authors include members of the National Center of Image-Guided Therapy program at Brigham and Womens Hospital and international leaders in the field of IGT.
  • pt. 1-2, 2009
    Christensen, Douglas A.
  • 2008
    Athanasiou, K. A.; Natoli, Roman M.
  • 2001 CRCnetBASE
    Northrop, Robert B.
  • 2007
    Ropella, Kristina M.
  • 2011
    Alvarez Icaza Rivera, Rodrigo; Boahen, Kwabena; Delp, Scott; Schnitzer, Mark Jacob.
    In this dissertation, I revisit Kawato's proposal, that the cerebellum predictively modulates descending motor commands, to achieve smooth and coordinated motion, by acquiring an inverse model of the biomechanical plant, and extend it by describing a novel and precise mapping between a cerebellar multizonal microcomplex and a joint's inverse model. This mapping renders two novel predictions: First, inferior olive's oscillations mirror the biomechanical joint's oscillations. Second, deep cerebellar neurons implement a gain factor, set by Purkinje cell inhibition, on inferior olive's signals to mirror the spinal cord's gain. I use biophysical modeling to show that oscillations within the inferior olive match the range of natural frequencies and damping ratios of biophysical joints, and that deep cerebellar neurons enable a multiplicative interaction between the Purkinje and the olivary pathways. Furthermore, I determine the effects of current injection into the inferior olive and the deep cerebellar nuclei and use these results within a control theory model to predict that experimentally disturbing the inferior olive will introduce motor output ringing, while disturbing the deep nuclei will also scale motor output. In both cases, manipulating the inverse model implemented by microzonal microcomplex will unmask the joint's natural dynamics as observed by motor ringing at the joint's natural frequency.
  • 2005 Springer
    Gilchrist, M. D.
  • 2005 CRCnetBASE
    Hollnagel, Erik; Woods, David D.
  • 2015 Springer
    Cortina, M. Soledad; De la Cruz, Jose.
    This book covers the field of keratoprosthesis in detail and focuses specifically on the Boston type 1 keratoprosthesis (KPro), which is the device most widely used today. Extensive information is provided on all aspects of KPro surgery, from history and preoperative evaluation to surgical techniques and postoperative management of complications. Surgical videos are included that will aid both beginning and advanced corneal surgeons in mastering these procedures. In addition, essential basic science concepts relevant to keratoprosthesis surgery are explained, and other keratoprostheses in use around the world are considered. A brief overview of integrating artificial corneas is provided, and the future of keratoprosthesis is also discussed. The book is written by some of the most distinguished and renowned experts in the field.
  • 2009
    Banik, Shantanu; Boag, Graham S.; Rangayyan, Rangaraj M.
  • 2011
    Ozuysal, Yusuf; Baccus, Stephen A.; Boahen, Kwabena; Shenoy, Krishna V.
    Neurons have a limited dynamic range. To more efficiently encode the large range of natural inputs, neural circuits adapt by dynamically changing their output range as a function of the input statistics. Variance adaptation provides an informative example of this process, whereby neurons change their response characteristics as a function of variance of their input. When their input distribution changes, sensory systems shift and scale their response curves to efficiently cover the new range of input values and they focus on different segments of the frequency spectrum, for example by choosing to average out the noise in a low signal-to-noise ratio environment by low-pass filtering their input and sacrificing resolution. In multiple sensory systems, adaptation to the variance of a sensory input changes the sensitivity, kinetics and average response over timescales ranging from < 100 ms to tens of seconds. Here we present a simple biophysically relevant model of retinal contrast adaptation that accurately captures both the membrane potential response and all adaptive properties. The adaptive component of this model is a first-order kinetic process of the type used to describe ion channel gating and synaptic transmission. We conclude that all adaptive dynamics can be accounted for by depletion of a signaling mechanism, and that contrast adaptation can be explained as adaptation to the mean of a thresholded signal. A diverse set of adaptive properties that implement theoretical principles of efficient coding can be generated by a single type of molecule or synapse with just a few microscopic states. The LNK model helps to highlight important aspects of adaptation by letting us focus on individual computational blocks separately. By using the LNK model, we investigate the source of the adaptive process in On-Off retinal ganglion cells, which show strong changes in their kinetics as a function of contrast. By analyzing properties of the LNK model, we conclude that most of the adaptive effect is due to differences in the threshold of the two pathways, with a smaller contribution from different adaptive kinetics. Adaptive temporal decorrelation in the retina arises due to differential thresholding in two parallel neural pathways.
  • 2011
    Rivera Alvidrez, Zuley; Newsome, William T.; Ng, Andrew Y.; Shenoy, Krishna V.
    Any time we move, our brains solve the difficult problem of translating our motor intentions to muscle commands. Understanding how this computation takes place, and in particular, what role the motor cortex plays in movement generation, has been a central issue in systems neuroscience that remains unresolved. In this thesis, we took an unconventional approach to the analysis of cortical neural activity and its relationship to executed movements. We used dimensionality reduction to extract the salient patterns of neural population activity, and related those to the muscle activity patterns generated during arm reaches to a grid of targets. We found that salient neural activity patterns appeared to tightly reflect muscle activity patterns with a biologically-plausible lag. We also applied our analyses to movements that were planned before being executed, and found that a muscle-framework view of the cortical activity was consistent with previously-described predictions of movement kinematics based on the state of the cortical population activity. Overall, our results elucidate remarkable simplicity of the motor-cortical activity at the population level, despite the complexity and heterogeneity of individual cell's activities.
  • 2011
    Miranda, Henrique do Carmo; Leeson, David B.; Meng, Teresa H.; Shenoy, Krishna V.
    Neural recording systems are fundamental to the advancement of brain-machine interfaces that can significantly improve the quality of lives of patients with neurological diseases, such as spinal cord injuries or quadriplegia. This thesis presents two newly developed wireless neural recording systems that are able to provide a high degree of usability and neural decoding accuracy. They are capable of simultaneously transmitting 32 to 96 channels of neural signals detected by an implanted neural sensor array. This work was carried out within the framework of the Hermes project and its technical design challenges will be addressed. The Hermes project is aimed at primarily developing hardware and software tools that extract neural information from the motor cortex. Those tools can enable practical prosthetic devices used to significantly ameliorate the life of patients with neurological impairments that directly affect motor functions. The first developed system, HermesD, is a 32-channel broadband transmission system using an FSK modulated carrier at 24 Mbit/s in the 3.7-4.1 GHz band. The link range extends beyond 20 m and the total power consumption is 142 mW. The HermesD system uses only COTS components and can be easily replicated. HermesD is fully operational and is currently used to transmit broadband neural data for neuroscience research in the Neural Prosthetic Systems Laboratory (NPSL) at Stanford University. HermesD is also planned as the base platform for future human trials to take place in the same laboratory. The second system that represents the next Hermes generation, HermesE, uses a novel UWB transmitter architecture implemented in a custom IC in the 65-nm CMOS technology. The transmitted signal bandwidth covers the 3.6 to 7.5 GHz frequency range. The time domain waveform is digitally programmable, allowing a very flexible control of the output spectrum to avoid interference and to allow multi-band operation. The UWB transmitter chip is part of a 96-channel broadband recording system delivering 40 Mbit/s. Its power consumption is 230 uW for a communication range of about 5 m. The antenna subsystems for these wireless recording devices presented a design challenge given the requirements for small size, large bandwidth and high efficiency. While HermesD has an operating FBW of 10%, HermesE is much more demanding in this respect, with 70% FBW, requiring unconventional antenna structures. The design techniques and performance of the antennas required to meet the specifications of both systems are also addressed in this work.
  • 2011
    Staroswiecki, Ernesto; Gold, Garry E.; Hargreaves, Brian A.; Pauly, John M.
    Osteoarthritis (OA) is a degenerative joint disease that affects over 80% of the population of the U.S. by age 65. However, there is currently no disease-modifying treatment for OA. In order to develop and evaluate potential treatments, it is necessary to assess cartilage health over the course of the disease. Here, an MRI method is presented to obtain sodium images of tissue that pushes the current state of the art of sodium MRI and can provide new information about cartilage. The method presented here enables sodium imaging at high resolution and with lower noise levels than previously reported. This technique uses custom-made radio-frequency (RF) coils and a 3D-cones k-space trajectory and is well suited to imaging at high field strengths like 3 T and 7 T. A second novel method is presented for generating high-resolution, 3D T2 and ADC maps of the human knee in vivo. The maps are derived from diagnostic-quality morphological MR images. This method is based on a new variation of the 3D double echo steady-state (DESS) sequence and solves many of the current challenges of traditional imaging techniques. Finally, a third method is presented allowing independent excitation of two or more volumes with a short RF pulse for MRI. This method enables different volumes to be excited with different RF pulse parameters, including flip angle, slice profile or thickness, phase modulation, etc., increasing the flexibility of the excitation. In summary, the techniques presented here generate measurements of sodium, T2, and ADC in cartilage, all biomarkers of interest for this tissue. These measurements are either less noisy or more efficiently obtained than with previous methods. The methods presented in this dissertation also improve the efficiency of diagnostic image acquisition for the knee.
  • 2011
    Krishnamurthy, Gaurav; Ingels, Neil B.; Miller, D. Craig; Nelson, Drew.
    The mitral valve (MV) is a bicuspid valve that allows the unidirectional flow of blood from the left atrium (LA) into the left ventricle (LV). MV disease afflicts millions each year worldwide and if sufficiently severe, surgical therapy is indicated. Surgical repair is currently preferred but valve replacement is often required. Current replacement therapy involves implantation of a mechanical valve, associated with anticoagulation/ thromboembolic complications, or a tissue valve, associated with less than ideal durability. To overcome these limitations, a currently important research goal is to create bioengineered autologous tissue valves. A key component of this thrust is to understand more completely the structure and function of native valves which reliably cycle 100,000 times per day, more than 3 billion times in an average lifetime. Toward this end, this thesis presents, for the first time, the material properties of the anterior mitral leaflet in the beating heart. The methodology used in this research is as follows: Surgical preparation and radiopaque marker data acquisition: 16 miniature radiopaque markers were sewn to the MV annulus, 16 to the anterior MV leaflet, and one on each papillary muscle tip in male sheep. 4-D coordinates were obtained from biplane videofluoroscopic marker images (60f/s) during three complete cardiac cycles. Data were acquired sequentially with repeat control runs between saddlehorn electrical pulse stimulation and intravenous administration of esmolol to study the effect of pharmacological agents on mitral leaflet contractility, and vagal nerve stimulation to assess the potential for central neural control. Inverse finite element analysis: A finite element model of the anterior MV leaflet was developed using marker coordinates at the end of isovolumic relaxation (IVR, when pressure difference across the valve is approximately zero), as the stress-free reference state. Leaflet displacements were simulated during IVR using measured left ventricular and atrial pressures. The elastic moduli in both the commisure-commisure (Ecirc) and radial (Erad) directions were optimized using the Method of Feasible Directions to minimize the difference between simulated and measured displacements. The derived material properties were found to be orders of magnitude greater than previously determined ex vivo material properties. Histologic studies have shown that the mitral leaflets, rather than being simple collagen flaps (as once thought), contain complex networks of contractile elements (smooth and striated muscle; valvular interstitial cells), blood vessels, and both afferent & efferent nerves. The finding of higher stiffness in vivo than ex vivo suggests a mechanistic role for these elements; to modulate the stiffness of the active mitral valve in vivo -- a property necessarily missing in excised, flaccid valves ex vivo. Using the derived material properties, a forward analysis was performed to determine the stress-strain behavior of the anterior leaflet at various trans-mitral pressure gradients during IVR. This analysis showed that the leaflet material behaved linearly over a physiologic range of pressures. It is also shown in this thesis that these leaflet material properties vary over the cardiac cycle; leaflet stiffness is higher during early systole (Isovolumic Contraction, IVC) most likely due to force development in cardiac muscle cells in the annular third of the anterior leaflet, and as this force development wanes during systole, the stiffness of the leaflet drops. Stimulation of the neutrally-rich annular saddlehorn region adjacent to the anterior leaflet was shown to almost double leaflet stiffness, whereas administration of a beta-blocker (Esmolol) eliminated the early systolic increase in anterior leaflet stiffness. The initial homogeneous finite element model of the anterior leaflet was further developed to incorporate regionally varying material properties. This heterogeneous finite element model confirmed that Esmolol selectively reduced leaflet stiffness in the annular region (which contains the slip of cardiac muscle) during IVC and did not affect edge stiffness (which is devoid of cardiac muscle). Saddlehorn stimulation caused an increase in leaflet stiffness values for all regions (edge, belly and annular regions) during both IVC and IVR. Loss of atrial contraction had a similar effect on the anterior leaflet as administration of Esmolol, i.e. without atrial depolarization the leaflet stiffness during IVC in the annular region dropped to baseline IVR values. Finally, the functional role of autonomic nerves in the anterior leaflet was investigated by remote stimulation of the vagus nerve. This study showed that vagal nerve stimulation can result in a decrease in anterior leaflet stiffness during both IVR and IVC. In summary, the findings of this thesis suggest a permanent paradigm shift from one viewing the mitral valve leaflets as passive flaps to one viewing the leaflets as active, potentially adaptive, neurally-controlled tissues whose complex function and dysfunction must be taken into account when considering not only therapeutic approaches to mitral valve disease, but even the definitions of mitral valve disease itself. The improved understanding of the structure-function relationships in these native, active valves could uncover new targets for pharmacologic intervention, as well as provide important insights to improve the future design and durability of tissue-engineered mitral valves.
  • 2013 Cambridge
    Blitterswijk, Clemens A. van; Boer, Jan de.
    "This complete, yet concise, guide introduces you to the rapidly developing field of high throughput screening of biomaterials: materiomics. Bringing together the key concepts and methodologies used to determine biomaterial properties, you will understand the adaptation and application of materomics in areas such as rapid prototyping, lithography and combinatorial chemistry. Each chapter is written by internationally renowned experts, and includes tutorial paragraphs on topics such as biomaterial-banking, imaging, assay development, translational aspects, and informatics. Case studies of state-of-the-art experiments provide illustrative examples, whilst lists of key publications allow you to easily read up on the most relevant background material. Whether you are a professional scientist in industry, a student, or a researcher, this book is not to be missed if you are interested in the latest developments in biomaterials research"--Provided by publisher.
  • 2006 Springer
    Lipson, Scott A.
  • 2010
    Chestek, Cynthia Anne; Meng, Teresa H.; Murmann, Boris; Newsome, William T.; Shenoy, Krishna V.
    Cortical brain-machine interfaces, or BMIs, is a relatively new field with the potential to provide many different clinical treatments, particularly for fully paralyzed patients. In these applications, multichannel electrode arrays are implanted into motor cortical areas in order to extract useful control signals. My research focuses on taking proof-of-concept academic BMI systems, and solving the engineering challenges that currently prevent them from being used in a clinical setting. These challenges include running a BMI for more than a few hours or a single day, and finding ways to minimize the size, cost, and operational complexity of the complete system. This dissertation includes an analysis of neuron stability over long timescales. I will show that the relationship between neurons in motor cortices and behavior remains stationary over time despite substantial noise, which could mitigate some concerns about long-term BMI performance. I will also discuss the development of HermesC, a wireless system for recording multichannel neural data from freely moving primates. This device dramatically reduces the size and cost of current recording technology for real-time neural prosthetic systems, and could be useful for human clinical trials. It may also enable neural prosthetic studies with animals in a less constrained setting. Combining traditional neural recordings with overnight wireless neural recordings, I will also show that there are substantial changes in neural waveforms from single neurons across days. However, the quality of neural decodes (the extraction of useful control signals) is only slightly improved by sorting individual units rather than using simple threshold crossings. This may enable long term BMI operation because multiunit neural "hash" on electrode arrays tends to persist for a long time, perhaps years, after single neuron signals have declined due to various tissue responses. In fact, other recent work from this project has demonstrated high performance neural decodes using only threshold crossings on arrays ~2.5 years after implantation.
  • 2010
    Chen, Julia Chinghua; Beaupré, Gary Scott; Carter, Dennis R.; Levenston, Marc Elliot.
    Our bones constantly adapt to their mechanical environment through a biological response from the womb to the tomb. Mechanobiology, the biological response to mechanical loading, is important for determining various properties of bone such as size and shape. During embryonic development, rapid growth generates significant tension in the periosteum, and tension has previously been shown to lead to bone apposition. In adults, intracortical stresses dominate and increased loading leads to elevated rates in bone apposition. Periosteal tension and intracortical stresses, then, are both experienced by bones, but their influences on bone apposition rates vary over time. This dissertation analyzes how embryonic bone growth rates and adult bone adaptation rates in long bones are related to their respective mechanical environments. The hypothesis that bones grow and adapt at rates corresponding to changes in the mechanical environment is investigated. In the first study, I investigated the mechanical environment of the periosteum during embryonic growth and its relationship to bone growth rates. The specific growth rate, or percent growth per day, was calculated using microCT images taken over embryonic days 11-20. Bones grew faster in length than in circumference during this time. Finite element techniques were then used to analyze the opening dimensions of incisions through the periosteum. Longitudinal and circumferential residual strains decreased from 46.2% to 29.3%, and 10.6% to 3.9%, respectively, during embryonic days 14-20. Residual strains were positively correlated to specific growth rates (p< 0.05). Many studies have investigated bone adaptation in adult mice and rats by applying loads to the long bones, and measuring changes in periosteal cortical bone apposition rates. However, results are difficult to compare because the loading schemes are generally different. The second study presents a theoretical framework for evaluating the mechanical stimulus based on the bone daily strain stimulus, which is a function of loading cycles and bone strains. The daily strain stimulus may act as a single unifying parameter for directly comparing data from existing in vivo experiments. Two approaches were used to determine the periosteal daily strain stimulus necessary for bone maintenance (xi_peri_0) and the strain-cycle weighting exponent (m), which are required to calculate the daily strain stimulus. In the first approach, data from bone maintenance studies were used to calculate xi_peri_0 to be 2793 microstrain/day, and m to be 4.5. In the second approach, strain gage recordings were used to calculate xi_peri_0 to be 1496 microstrain/day, and human bone compressive fatigue properties were used to assign m to be 11.88. Bone apposition rates generally increased with increasing daily strain stimulus, which was consistent with previous theoretical models. The third study provides examples of how the daily strain stimulus may be used to examine the effects of specific loading parameters on bone apposition rates. The effects of inserting periods of rest and frequency were examined. Inserting periods of rest during loading appeared to increase bone apposition rates by approximately 64% compared to continuously loaded bones. Frequency has been previously suggested to be most osteogenic at 5-10 Hz. Using this analysis, an increase in bone apposition rate was also observed at 10 Hz. The results of these studies provide insight into the effects of periosteal tension during embryonic development and intracortical strains during adulthood on bone apposition rates. These findings illustrate how important the mechanical loads experienced by bones and their surrounding tissues are in determining the sizes and shapes of bones.
  • 2015 Atypon
    Saunders, Marnie M.
    Mechanical testing is a useful tool in the field of biomechanics. Classic biomechanics employs mechanical testing for a variety of purposes. For instance, testing may be used to determine the mechanical properties of bone under a variety of loading modes and various conditions including age and disease state. In addition, testing may be used to assess fracture fixation procedures to justify clinical approaches. Mechanical testing may also be used to test implants and biomaterials to determine mechanical strength and appropriateness for clinical purposes. While the information from a mechanical test will vary, there are basics that need to be understood to properly conduct mechanical testing. This book will attempt to provide the reader not only with the basic theory of conducting mechanical testing, but will also focus on providing practical insights and examples.
  • 2013 CRCnetBASE
    Qin, Qing-Hua.
    Introduction to bone materials -- Basic bone remodeling theory -- Multifield internal bone remodeling -- Multifield surface bone remodeling -- Theoretical models of bone modeling and remodeling -- Effect of parathyroid hormone on bone metabolism -- Cortical bone remodeling under mechanical stimulus -- Bone remodelling under pulsed electromagnetic fields and clinical applications -- Experiments.
  • 2010
    Goergen, Craig Jonathan; Dalman, Ronald L.; Taylor, Charles A.; Tsao, Philip.
    The aorta is the largest blood vessel in the body, responsible for carrying blood from the heart directly to most major organs and ending at the iliac arteries which feed the lower extremities. This elastic vessel provides much of the vascular system's compliance and is composed of a heterogeneous mixture of smooth muscle cells, collagen, and elastin. The general purpose of our work has been to use in vivo imaging to determine abdominal aortic dynamics in a variety of healthy and diseased cases. First, a cross-species analysis in mice, rats, rabbits, pigs and humans showed with M-mode ultrasound that infrarenal abdominal aortic motion was similar in animals and humans, regardless of aortic size. Greater anterior than posterior wall motion was observed and aortic wall displacement increased linearly with diameter. Next, cardiovascular abnormalities in a recently developed mouse model for Williams-Beuren Syndrome (WBS) were investigated. WBS is a rare genetic disorder caused by a heterozygous 1.5-megabase deletion, which typically includes the elastin gene. In this study, we showed that Wbs mice have hypertension, reduced in vivo cyclic strain, and fragmented medial elastin sheets - all characteristics similar to human WBS. These data provide insight into the genotype-phenotype relationship between elastin levels, aortic stiffness, and the cardiovascular abnormalities associated with WBS and other microdeletion syndromes. Finally, the biomechanical influences on murine models of abdominal aortic aneurysms (AAA), a pathological dilation of the abdominal aorta, were investigated using magnetic resonance imaging. From this work, we showed that the location of aneurysm development may be correlated with the location of maximum abdominal aortic curvature in angiotensin II-induced murine AAAs. This model consistently forms abdominal aneurysms with repeatable leftward vessel expansion above the renal arteries. Our work has shown that this leftward saccular shape is likely influenced by leftward suprarenal aortic curvature and motion. Histological analysis provided evidence for degradation of medial elastin at one focal location on the left side of the vessel, with a majority of animals also developing an adventitial hematoma at a similar circumferential location. Conversely, elastase-induced infrarenal murine AAAs do not form in a location of high vessel curvature and do not expand in one general direction. This work will help to further our understanding of the role mechanics may play in AAA formation, progression, and eventual rupture.
  • 2003 ANSI, Click fulltext button, Click guest acess (upper right) and Search for standard number 13485
    Also available: Print – 2003
  • 2006. CRCnetBASE
    Bronzino, Joseph D.
    Infrared imaging applied to dentistry -- Use of infrared imaging in veterinary medicine -- Standard procedures for infrared imaging in medicine -- Infrared detectors and detector arrays -- Infrared camera characterization -- Infrared camera and optics for medical applications -- sect. IV. Medical informatics. Hospital information systems: their function and state -- Computer-based patient records -- Overview of standards related to the emerging health care information infrastructure -- Introduction to informatics and nursing -- Non-AI decision making -- Medical informatics and biomedical emergencies: new training and simulation technologies for first responders -- sect. V. Biomedical sensors. Physical measurements -- Biopotential electrodes -- Electrochemical sensors -- Optical sensors -- Bioanalytic sensors -- Biological sensors for diagnostics -- sect. VI. Medical instruments and devices. Biopotential amplifiers -- Bioelectric impedance measurements -- Implantable cardiac pacemakers -- Medical instruments and devices used in the home -- Virtual instrumentation: applications in biomedical engineering -- sect. VII. Clinical engineering. Clinical engineering: evolution of a discipline -- Management and assessment of medical technology -- Risk factors, safety, and management of medical equipment -- Clinical engineering program indicators -- Quality of improvement and team building -- A standards primer for clinical engineers -- Regulatory and assessment agencies -- Applications of virtual instruments in health care -- sect. VIII. Ethical issues associated with the use of medical technology. Beneficence, nonmaleficence, and medical technology -- Ethical issues related to clinical research. Noninvasive arterial blood pressure and mechanics -- Cardiac output measurement -- External defibrillators -- Implantable defibrillators -- Implantable stimulators for neuromuscular control -- Respiration -- Mechanical ventilation -- Essentials of anesthesia delivery -- Electrosurgical devices -- Biomedical lasers -- Instrumentation for cell mechanics -- Blood glucose monitoring -- Atomic force microscopy: probing biomolecular interactions -- Parenteral infusion devices -- Clinical laboratory: separation and spectral methods -- Clinical laboratory: nonspectral methods and automation -- Noninvasive optical monitoring -- Sect. I. Biomedical signal analysis. Biomedical signals: origin and dynamic characteristics, frequency-domain analysis -- Digital biomedical signal acquisition and processing -- Compression of digital biomedical signals -- Time-frequency signal representations for biomedical signals -- Wavelet (time-scale) analysis in biomedical signal processing -- Higher-order spectral analysis -- Neural networks in biomedical signal processing -- complexity, scaling, and fractals in biomedical signals -- Future directions: biomedical signal processing and networked multimedia communications -- sect. II. Imaging. X-ray -- Computed tomography -- Magnetic resonance imaging -- Nuclear medicine -- Ultrasound -- Magnetic resonance microscopy -- Positron-emission tomography (PET) -- Electrical impedance tomography -- Medical applications of virtual reality technology -- Sect. III. Infrared imaging. Advances in medical infrared imaging -- The historical development of thermometry and thermal imaging in medicine -- Physiology of thermal signals -- Quantitative active dynamic thermal IR-imaging and thermal tomography in medical diagnostics -- Thermal texture maps (TTM): concept, theory, and applications -- IR imagers as fever monitoring devices: physics, physiology, and clinical accuracy -- Infrared imaging of the breast - an overview -- Functional infrared imaging of the breast: historical perspectives, current applications, and future considerations -- Detecting breast cancer from thermal infrared images by asymmetry analysis -- Advanced thermal image processing -- Biometrics: face recognition in thermal infrared -- Infrared imaging for tissue characterization and function -- Thermal imaging in diseases of the skeletal and neuromuscular systems -- Functional infrared imaging in clinical applications -- Thermal imaging in surgery --
  • 2010 WHO
    Also available: Print – 2010
  • 2012 Atypon
    Wang, Binseng.
    In addition to being essential for safe and effective patient care, medical equipment also has significant impact on the income and, thus, vitality of healthcare organizations. For this reason, its maintenance and management requires careful supervision by healthcare administrators, many of whom may not have the technical background to understand all of the relevant factors. This book presents the basic elements of medical equipment maintenance and management required of healthcare leaders responsible for managing or overseeing this function. It will enable these individuals to understand their professional responsibilities, as well as what they should expect from their supervised staff and how to measure and benchmark staff performance against equivalent performance levels at similar organizations. The book opens with a foundational summary of the laws, regulations, codes, and standards that are applicable to the maintenance and management of medical equipment in healthcare organizations. Next, the core functions of the team responsible for maintenance and management are described in sufficient detail for managers and overseers. Then the methods and measures for determining the effectiveness and efficiency of equipment maintenance and management are presented to allow performance management and benchmarking comparisons. The challenges and opportunities of managing healthcare organizations of different sizes, acuity levels, and geographical locations are discussed. Extensive bibliographic sources and material for further study are provided to assist students and healthcare leaders interested in acquiring more detailed knowledge.
  • 2001 CRCnetBASE
    Hajnal, Joseph V.; Hawkes, D. J.; Hill, Derek L. G.
  • 2007 CRCnetBASE
    Story, Molly Follette; Winters, Jack M.
  • Clark, John W.; Webster, John G.
    Basic concepts of medical instrumentation / Walter H. Olson -- Basic sensors and principles / Robert A. Peura and John G. Webster -- Amplifiers and signal processing / John G. Webster -- The origin of biopotentials / John W. Clark, Jr. -- Biopotential electrodes / Michael R. Neuman -- Biopotential amplifiers / Michael R. Neuman -- Blood pressure and sound / Robert A. Peura -- Measurement of flow and volume of blood / John G. Webster -- Measurements of the respiratory system / Frank P. Primiano, Jr. -- Chemical biosensors / Robert A. Peura -- Clinical laboratory instrumentation / Lawrence A. Wheeler -- Medical imaging systems / Melvin P. Siedband -- Therapeutic and prosthetic devices / Michael R. Neuman -- Electrical safety / Walter H. Olson.

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