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- ArticleDhavale VM, Singh SK, Nadeema A, Gaikwad SS, Kurungot S.Nanoscale. 2015 Dec 21;7(47):20117-25.The size-controlled growth of nanocrystalline Fe-Fe2O3 particles (2-3 nm) and their concomitant dispersion on N-doped graphene (Fe-Fe2O3/NGr) could be attained when the mutually assisted redox reaction between NGr and Fe(3+) ions could be controlled within the aqueous droplets of a water-in-oil emulsion. The synergistic interaction existing between Fe-Fe2O3 and NGr helped the system to narrow down the overpotential for the oxygen reduction reaction (ORR) by bringing a significant positive shift to the reduction onset potential, which is just 15 mV higher than its Pt-counterpart. In addition, the half-wave potential (E1/2) of Fe-Fe2O3/NGr is found to be improved by a considerable amount of 135 mV in comparison to the system formed by dispersing Fe-Fe2O3 nanoparticles on reduced graphene oxide (Fe-Fe2O3/RGO), which indicates the presence of a higher number of active sites in Fe-Fe2O3/NGr. Despite this, the ORR kinetics of Fe-Fe2O3/NGr are found to be shifted significantly to the preferred 4-electron-transfer pathway compared to NGr and Fe-Fe2O3/RGO. Consequently, the H2O2% was found to be reduced by 78.3% for Fe-Fe2O3/NGr (13.0%) in comparison to Fe-Fe2O3/RGO (51.2%) and NGr (41.0%) at -0.30 V (vs. Hg/HgO). This difference in the yield of H2O2 formed between the systems along with the improvements observed in terms of the oxygen reduction onset and E1/2 in the case of Fe-Fe2O3/NGr reveals the activity modulation achieved for the latter is due to the coexistence of factors such as the presence of the mixed valancies of iron nanoparticles, small size and homogeneous distribution of Fe-Fe2O3 nanoparticles and the electronic modifications induced by the doped nitrogen in NGr. A controlled interplay of these factors looks like worked favorably in the case of Fe-Fe2O3/NGr. As a realistic system level validation, Fe-Fe2O3/NGr was employed as the cathode electrode of a single cell in a solid alkaline electrolyte membrane fuel cell (AEMFC). The system could display an open circuit voltage (OCV) of 0.73 V and maximum power and current densities of 54.40 mW cm(-2) and 200 mA cm(-2), respectively, which are comparable to the performance characteristics of a similar system derived by using 40 wt% Pt/C as the cathode electrode.
- ArticleBhatt B, Bhatt N, Karki A, Giri G, Baaniya B, Neupane B, Bogati S, Mahaju S, Poudel A, Pokharel S, Kafle N, Nepal S, Sapkota R, Shrestha S, Tuitui RL, Sagtani RA.Heliyon. 2023 Sep;9(9):e20117.Introduction: Intimate partner violence (IPV) is a significant public health concern in Nepal and its prevalence has increased during the COVID-19 pandemic. This study aimed to assess the prevalence of IPV among married women of reproductive age in Nepal during the pandemic.
Methods: A web-based survey was conducted with 420 participants using a validated questionnaire adopted from the World Health Organization. Descriptive and inferential statistical analyses were performed.
Results: Our study found that 52.62% of participants experienced IPV during the COVID-19 pandemic with economic violence being the most prevalent type (38.81%) and followed by behavioral control (37.14%), emotional violence (26.20%), physical violence (21.43%), and sexual violence (14.05%). Despite the high level of IPV, only 14% of participants sought help and only 6% reported the violence to the police. Univariate analyses showed that factors such as the husband's level of education and occupation, number of children, property ownership, husband's alcohol use, relationship and quarrels with the husband, fear of the husband, and participation in decision-making were associated with an increased risk of IPV. Multivariate analysis revealed that women involved in decision-making faced a 2.52 times higher risk of violence, that women who reported daily quarrels had a risk 5.47 times that of women who did not endorse fights, and that women who were afraid of their husbands had a risk 16 times that of women who did not report fear.
Conclusion: This study reveals a concerning prevalence of IPV among married women in Nepal during the COVID-19 pandemic. Our findings emphasize the low reporting rates and help-seeking behavior among IPV victims. They also highlight the significant influence of factors such as participation in decision-making, frequent quarrels, and fear. These findings underscore the urgent need to establish support systems for IPV victims and develop targeted interventions tailored to the local context. Furthermore, conducting comprehensive research and understanding the interplay of contributing factors can guide the formulation of effective strategies to combat this pervasive societal problem. - ArticleYang Q, Tang J, Huang X, Huang K.Sci Rep. 2024 08 29;14(1):20117.Gibberellin (GA3) is an important plant hormone involved in many physiological and developmental processes in plants. However, the physiological mechanism of GA3 on the regulation yield and grain shell thickness of Tartary buckwheat is still unclear. In this study, the thick-shelled cultivar "Jinqiao 2" and thin-shelled cultivar "Miku 18" were used to study the effects of different concentrations (0, 50, and 100 mg L-1) of exogenous GA3 and chlorocholine chloride (CCC, GA3 synthesis inhibitor) on the cellulose content, amylase, and sucrose synthase (SS) activity in grain shell and the yield of Tartary buckwheat. The application of exogenous GA3 can improve the cellulose content and the activity of amylase and SS in the grain shell of the two Tartary buckwheat varieties. It can also increase the main stem node number, main stem branch number, grains per plant, and yield. Compared with the control treatment (CK, 0 mg L-1), the 100 mg/L exogenous GA3 treatment increased the number of grains per plant, grain weight per plant, 1000-grain weight, and yield of Jinqiao 2 by 20.1%, 41.9%, 13%, and 34.7%, respectively. These items of Miku 18 were increased by 26%, 15.2%, 10.2%, and 23.8%. The application of CCC reduced the activity of amylase and SS and cellulose content in grain shell. In addition, it decreased the main stem node number, main stem branch number, grains per plant, and yield of Tartary buckwheat. In summary, exogenous GA3 treatment not only improved the yield of Tartary buckwheat but also increased the thickness of grain shell by enhancing the activity of amylase and SS and promoting the synthesis and accumulation of cellulose. The results can provide theoretical references for clarifying the physiological mechanism of the difference in shell thickness between Tartary buckwheat varieties.
- ArticleManasrah N, Abdelazeem B, Al Qasem S, Kandah E, Chaudhary AJ.Cureus. 2021 Dec;13(12):e20117.Near-fatal asthma (NFA) is a life-threatening condition that represents the most severe clinical phenotype of asthma and can progress to fatal asthma. Patients with NFA do not respond adequately to conventional medical therapy and urgent intervention is needed to provide adequate oxygenation by invasive mechanical ventilation. While mechanical ventilation is a potentially life-saving intervention, it could cause lung injury, barotrauma, and dynamic hyperinflation due to high ventilator settings resulting in hemodynamic instability. Extracorporeal membrane oxygenation (ECMO) provides full respiratory support with adequate gas exchange in patients with NFA and improves survival rate. We present a case of a young female patient who presented with NFA, and her clinical condition was worsening despite invasive positive pressure mechanical ventilation.
- ArticleZou Q, Xu B, Wang W, Hu Y, Liu T, Li Q, Ma T, Zheng H, Huo Z.Nanoscale. 2024 Nov 07;16(43):20100-20117.Coalbed methane is a crucial component of unconventional natural gas, essential for energy strategies. However, its extraction is often impeded by coal and gas outbursts, which pose significant safety and operational challenges. Coal seam water injection is an effective method for preventing these outbursts, and SiO2 nanofluids can enhance this method by improving coal seam wettability. Nevertheless, the microscopic mechanical properties of SiO2 nanofluid-wetted coal samples remain unclear, complicating the understanding of the enhancement mechanism against outbursts. This study employed nanoindentation tests, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) to analyze the effects of SiO2 nanofluids at concentrations of 0.5 wt%, 1.0 wt%, and 1.5 wt%, comparing them to untreated coal samples. The results reveal that SiO2 nanofluid-modified coal samples exhibit an increased degree of softening, with hardness reduced by up to 21.51% and elastic modulus decreased by up to 27.97%. SEM images and EDX analysis show that lower concentration SiO2 nanofluids weaken coal samples by enhancing their water absorption capacity and reducing cohesion, while higher concentration nanofluids strengthen coal samples by filling and covering microcracks, thereby limiting moisture entry. These findings provide a quantitative reference for the application of SiO2 nanofluids and guide the selection of optimal nanofluid concentrations.
- ArticleReindl-Schwaighofer R, Hödlmoser S, Domenig O, Krenn K, Eskandary F, Krenn S, Schörgenhofer C, ... Show More Rumpf B, Karolyi M, Traugott MT, Abrahamowicz A, Tinhof V, Mayfurth H, Rathkolb V, Mußnig S, Schmölz L, Ullrich R, Heinzel A, König F, Binder C, Bonderman D, Strassl R, Puchhammer-Stöckl E, Gorkiewicz G, Aberle JH, Jilma B, Wenisch C, Poglitsch M, Oberbauer R, Zoufaly A, Hecking M.Sci Rep. 2022 11 22;12(1):20117.SARS-CoV-2 gains cell entry via angiotensin-converting enzyme (ACE) 2, a membrane-bound enzyme of the "alternative" (alt) renin-angiotensin system (RAS). ACE2 counteracts angiotensin II by converting it to potentially protective angiotensin 1-7. Using mass spectrometry, we assessed key metabolites of the classical RAS (angiotensins I-II) and alt-RAS (angiotensins 1-7 and 1-5) pathways as well as ACE and ACE2 concentrations in 159 patients hospitalized with COVID-19, stratified by disease severity (severe, n = 76; non-severe: n = 83). Plasma renin activity (PRA-S) was calculated as the sum of RAS metabolites. We estimated ACE activity using the angiotensin II:I ratio (ACE-S) and estimated systemic alt-RAS activation using the ratio of alt-RAS axis metabolites to PRA-S (ALT-S). We applied mixed linear models to assess how PRA-S and ACE/ACE2 concentrations affected ALT-S, ACE-S, and angiotensins II and 1-7. Median angiotensin I and II levels were higher with severe versus non-severe COVID-19 (angiotensin I: 86 versus 30 pmol/L, p < 0.01; angiotensin II: 114 versus 58 pmol/L, p < 0.05), demonstrating activation of classical RAS. The difference disappeared with analysis limited to patients not taking a RAS inhibitor (angiotensin I: 40 versus 31 pmol/L, p = 0.251; angiotensin II: 76 versus 99 pmol/L, p = 0.833). ALT-S in severe COVID-19 increased with time (days 1-6: 0.12; days 11-16: 0.22) and correlated with ACE2 concentration (r = 0.831). ACE-S was lower in severe versus non-severe COVID-19 (1.6 versus 2.6; p < 0.001), but ACE concentrations were similar between groups and correlated weakly with ACE-S (r = 0.232). ACE2 and ACE-S trajectories in severe COVID-19, however, did not differ between survivors and non-survivors. Overall RAS alteration in severe COVID-19 resembled severity of disease-matched patients with influenza. In mixed linear models, renin activity most strongly predicted angiotensin II and 1-7 levels. ACE2 also predicted angiotensin 1-7 levels and ALT-S. No single factor or the combined model, however, could fully explain ACE-S. ACE2 and ACE-S trajectories in severe COVID-19 did not differ between survivors and non-survivors. In conclusion, angiotensin II was elevated in severe COVID-19 but was markedly influenced by RAS inhibitors and driven by overall RAS activation. ACE-S was significantly lower with severe COVID-19 and did not correlate with ACE concentrations. A shift to the alt-RAS axis because of increased ACE2 could partially explain the relative reduction in angiotensin II levels.
- ArticleCosta ZP, Varani AM, Cauz-Santos LA, Sader MA, Giopatto HA, Zirpoli B, Callot C, Cauet S, Marande W, Souza Cardoso JL, Pinheiro DG, Kitajima JP, Dornelas MC, Harand AP, Berges H, Monteiro-Vitorello CB, Carneiro Vieira ML.Plant Genome. 2021 11;14(3):e20117.The genus Passiflora comprises a large group of plants popularly known as passionfruit, much appreciated for their exotic flowers and edible fruits. The species (∼500) are morphologically variable (e.g., growth habit, size, and color of flowers) and are adapted to distinct tropical ecosystems. In this study, we generated the genome of the wild diploid species Passiflora organensis Gardner by adopting a hybrid assembly approach. Passiflora organensis has a small genome of 259 Mbp and a heterozygosity rate of 81%, consistent with its reproductive system. Most of the genome sequences could be integrated into its chromosomes with cytogenomic markers (satellite DNA) as references. The repeated sequences accounted for 58.55% of the total DNA analyzed, and the Tekay lineage was the prevalent retrotransposon. In total, 25,327 coding genes were predicted. Passiflora organensis retains 5,609 singletons and 15,671 gene families. We focused on the genes potentially involved in the locus determining self-incompatibility and the MADS-box gene family, allowing us to infer expansions and contractions within specific subfamilies. Finally, we recovered the organellar DNA. Structural rearrangements and two mitoviruses, besides relics of other mobile elements, were found in the chloroplast and mt-DNA molecules, respectively. This study presents the first draft genome assembly of a wild Passiflora species, providing a valuable sequence resource for genomic and evolutionary studies on the genus, and support for breeding cropped passionfruit species.
- ArticleHu TH, Rosli N, Mohamad DSA, Kadir KA, Ching ZH, Chai YH, Ideris NN, Ting LSC, Dihom AA, Kong SL, Wong EKY, Sia JEH, Ti T, Chai IPF, Tang WY, Hii KC, Divis PCS, Davis TME, Daneshvar C, Singh B.Sci Rep. 2021 10 11;11(1):20117.Plasmodium knowlesi, a simian malaria parasite responsible for all recent indigenous cases of malaria in Malaysia, infects humans throughout Southeast Asia. There are two genetically distinct subpopulations of Plasmodium knowlesi in Malaysian Borneo, one associated with long-tailed macaques (termed cluster 1) and the other with pig-tailed macaques (cluster 2). A prospective study was conducted to determine whether there were any between-subpopulation differences in clinical and laboratory features, as well as in epidemiological characteristics. Over 2 years, 420 adults admitted to Kapit Hospital, Malaysian Borneo with knowlesi malaria were studied. Infections with each subpopulation resulted in mostly uncomplicated malaria. Severe disease was observed in 35/298 (11.7%) of single cluster 1 and 8/115 (7.0%) of single cluster 2 infections (p = 0.208). There was no clinically significant difference in outcome between the two subpopulations. Cluster 1 infections were more likely to be associated with peri-domestic activities while cluster 2 were associated with interior forest activities consistent with the preferred habitats of the respective macaque hosts. Infections with both P. knowlesi subpopulations cause a wide spectrum of disease including potentially life-threatening complications, with no implications for differential patient management.
- ArticleGrynko O, Thibault T, Pineau E, Juska G, Reznik A.Sci Rep. 2020 11 18;10(1):20117.Polycrystalline Lead Oxide (poly-PbO) was considered one of the most promising photoconductors for the direct conversion X-ray medical imaging detectors due to its previous success in optical imaging, i.e., as an optical target in so-called Plumbicon video pick-up tubes. However, a signal lag which accompanies X-ray excitation, makes poly-PbO inapplicable as an X-ray-to-charge transducer in real-time X-ray imaging. In contrast, the recently synthesized Amorphous Lead Oxide (a-PbO) photoconductor is essentially lag-free. Here, we report on our approach to a PbO detector where a thin layer of a-PbO is combined with a thick layer of poly-PbO for lag-free operation. In the presented a-PbO/poly-PbO bilayer structure, the poly-PbO layer serves as an X-ray-to-charge transducer while the a-PbO acts as a lag prevention layer. The hole mobility in the a-PbO/poly-PbO bilayer structure was measured by photo-Charge Extraction by Linearly Increasing Voltage technique at different temperatures and electric fields to investigate charge transport properties. It was found that the hole mobility is similar to that in a-Se-currently the only commercially viable photoconductor for the direct conversion X-ray detectors. Evaluation of the X-ray temporal performance demonstrated complete suppression of signal lag, allowing operation of the a-PbO/poly-PbO detector in real-time imaging.
- ArticleLi HF, Xing BP, Song LS, Wang W, Liu BH.Medicine (Baltimore). 2020 May 22;99(21):e20117.INTRODUCTION: Central airway stenosis is a life-threating requiring immediate medical intervention. There are several options for treating central airway stenosis, including rigid bronchoscopy, bronchoscopic high-power laser therapy, high-frequency electric needle knife, and balloon-expanding stents. However, interventional techniques may be unavailable in an emergent situation or at smaller local hospitals. In this case report, we publicly demonstrate for the first time that a tracheal intubation catheter may be applied as a temporary alternative to interventional bronchoscopic treatment.
PATIENT CONCERNS: A 72-year old male patient was admitted with a 1-year history of intermittent dyspnea, which was exacerbated for one day. One day prior to admission to our hospital, the patient presented with cyanosis due to an exacerbation of dyspnea.A tracheotomy was performed and the patient had been carrying a tracheotomy cannula for 6 months.
DIAGNOSIS: The ventilator alarm indicated high airway resistance and the nurses were unable to insert the suction pipes into the airway. Immediate fiberoptic bronchoscopy showed diffuse edema and stenosis of the inferior tracheal airways.
INTERVENTIONS: Tracheal intubation was used to temporarily replace the tracheotomy cannula, which successfully expanded the narrowed airways.
OUTCOMES: The blood oxygen saturation returned to normal, and dyspnea was quickly relieved.
CONCLUSION: In emergent situations, tracheal intubation catheters may be used in patients with post-tracheotomy central airway stenosis, not only for surviving the most dangerous phase but for also prolonging the survival time for further treatments. - ArticleGraul J, Lilly T.Opt Express. 2014 Aug 25;22(17):20117-29.Broadband coherent Rayleigh-Brillouin scattering (CRBS) was used to measure translational gas temperatures for nitrogen, argon, and methane at the ambient pressure of 0.8 atm. Temperatures derived from spectral analysis were compared with experimentally-measured temperatures, with a maximum 5.2% difference for all gases at all temperatures; and with nitrogen, argon, and methane exhibiting average differences over the temperature range tested of 0.8%, 1.4% and -0.5%, respectively. These values are consistent with the 2% estimated, experimental error of the experiment. Improving upon the efficiency of previous line shape acquisition methods, CRBS data were spectrally de-convolved using a cost effective, purpose-designed, Fabry-Perot etalon spectrometer. The resulting line shapes were compared to models obtained from approximations to the 1D Boltzmann equation. Although this study employed broadband CRBS for explicit gas temperature measurement, similar line shape acquisition techniques could be used with broadband coherent Rayleigh scattering (CRS) to experimentally-measure gas temperatures, pressures and other transport properties in both the kinetic (CRBS) and rarefied (CRS) regimes.
- BookTricia Hersey.Summary: Disrupt and push back against capitalism and white supremacy. In this book, Tricia Hersey, aka The Nap Bishop, encourages us to connect to the liberating power of rest, daydreaming, and naps as a foundation for healing and justice. What would it be like to live in a well-rested world? Far too many of us have claimed productivity as the cornerstone of success. Brainwashed by capitalism, we subject our bodies and minds to work at an unrealistic, damaging, and machine-level pace -- feeding into the same engine that enslaved millions into brutal labor for its own relentless benefit. In Rest Is Resistance, Tricia Hersey, aka the Nap Bishop, casts an illuminating light on our troubled relationship with rest and how to imagine and dream our way to a future where rest is exalted. Our worth does not reside in how much we produce, especially not for a system that exploits and dehumanizes us. Rest, in its simplest form, becomes an act of resistance and a reclaiming of power because it asserts our most basic humanity. We are enough. The systems cannot have us. Rest Is Resistance is rooted in spiritual energy and centered in Black liberation, womanism, somatics, and Afrofuturism. With captivating storytelling and practical advice, all delivered in Hersey's lyrical voice and informed by her deep experience in theology, activism, and performance art, Rest Is Resistance is a call to action, a battle cry, a field guide, and a manifesto for all of us who are sleep deprived, searching for justice, and longing to be liberated from the oppressive grip of Grind Culture.Digital Access 2022Limited to 1 simultaneous userSUNet ID login required
- ArticleGuan C, Cen HF, Cui X, Tian DY, Tadesse D, Zhang YW.Sci Rep. 2019 12 27;9(1):20117.Transgenic switchgrass overexpressing Lolium perenne L. delta1-pyrroline 5-carboxylate synthase (LpP5CS) in group I (TG4 and TG6 line) and group II (TG1 and TG2 line) had significant P5CS and ProDH enzyme activities, with group I plants (TG4 and TG6) having higher P5CS and lower ProDH enzyme activity, while group II plants had higher ProDH and lower P5CS enzyme activity. We found group II transgenic plants showed stunted growth, and the changed proline content in overexpressing transgenic plants may influence the growth and development in switchgrass. RNA-seq analysis showed that KEGG enrichment included phenylpropanoid biosynthesis pathway among group I, group II and WT plants, and the expression levels of genes related to lignin biosynthesis were significantly up-regulated in group II. We also found that lignin content in group II transgenic plants was higher than that in group I and WT plants, suggesting that increased lignin content may suppress switchgrass growth and development. This study uncover that proline can appropriately reduce lignin biosynthesis to improve switchgrass growth and development. Therefore, appropriate reduction in lignin content and increase in biomass are important for bioenergy crop to lower processing costs for biomass fermentation-derived fuels.
- ArticleGao Y, Zheng F, Wang D, Wang B.Nanoscale. 2020 Oct 15;12(39):20100-20117.The volume change and concurrent stress evolution of electrode materials during the cycling of lithium-ion batteries can cause severe mechanical issues such as the fracture of active materials and electrodes, thus leading to safety issues and capacity fading. Recent years have witnessed a thriving interest to gain a complete understanding of battery electrode materials from the viewpoint of mechanics. This review paper aims at discussing battery electrode materials from a mechanical perspective to provide an overview of the recent innovative efforts in this field. On the one hand, we introduce the mechanical issues of active materials and electrodes in the electrochemical processes, along with a focus on the strategies developed for enhancing the mechanical strength of electrode materials and constructing mechanically robust electrodes. On the other hand, experimental and theoretical studies on the stress-regulated effects on electrochemical processes are discussed to demonstrate the intriguing role of mechanical stress as an enabler in electrochemistry. We also give an outlook on the promising research topics for understanding the material mechanical issues, reinforcing electrode materials and improving battery performance.
- ArticleWang X, Kong L, Zhang Z, Wang H, Lu X.Sci Rep. 2023 Nov 17;13(1):20117.The YOLOv4 approach has gained significant popularity in industrial object detection due to its impressive real-time processing speed and relatively favorable accuracy. However, it has been observed that YOLOv4 faces challenges in accurately detecting small objects. Its bounding box regression strategy is rigid and fails to effectively leverage the asymmetric characteristics of objects, limiting its ability to enhance object detection accuracy. This paper proposes an enhanced version of YOLOv4 called KR-AL-YOLO (keypoint regression strategy and angle loss based YOLOv4). The KR-AL-YOLO approach introduces two customized modules: an keypoint regression strategy and an angle-loss function. These modules contribute to improving the algorithm's detection accuracy by enabling more precise localization of objects. Additionally, KR-AL-YOLO adopts an improved feature fusion technique, which facilitates enhanced information flow within the network, thereby further enhancing accuracy performance. Experimental evaluations conducted on the COCO2017 dataset demonstrate the effectiveness of the proposed method. KR-AL-YOLO achieves an average precision of 45.6%, surpassing both YOLOv4 and certain previously developed one-stage detectors. The utilization of keypoint regression strategy and the incorporation of robust feature fusion contribute to superior object detection accuracy in KR-AL-YOLO compared to YOLOv4.
- ArticleRéant BLL, Whitehead GFS, Mehta M.Inorg Chem. 2024 Oct 28;63(43):20117-20125.Clusters of the main group elements phosphorus and arsenic, commonly categorized as Zintl clusters, have been known for over a century. And, only now is the application of these systems as catalysts for organic synthesis being investigated. In this work, boranes are tethered via an aliphatic linker to Zintl-based clusters and their Lewis acidity is examined experimentally, by the Gutmann-Beckett test and competency in the hydroborative reduction of six organic substrates, as well as computationally, by fluoride ion affinity and hydride ion affinity methods. The effects of tuning the aliphatic linker length, substituents at the boron, and changing the cluster from a seven-atom phosphorus system to a seven-atom arsenic system on reactivity are studied.
- ArticleWang W, Roppo V, Kalinowski K, Kong Y, Neshev DN, Cojocaru C, Trull J, Vilaseca R, Staliunas K, Krolikowski W, Saltiel SM, Kivshar Y.Opt Express. 2009 Oct 26;17(22):20117-23.We study parametric frequency conversion in quadratic nonlinear media with disordered ferroelectric domains. We demonstrate that disorder allows realizing broadband third-harmonic generation via cascading of two second-order quasi-phase matched nonlinear processes. We analyze both spatial and polarization properties of the emitted radiation and find the results in agreement with our theoretical predictions.
- ArticleKazmin R, Rose A, Szczepek M, Elgeti M, Ritter E, Piechnick R, Hofmann KP, Scheerer P, Hildebrand PW, Bartl FJ.J Biol Chem. 2015 Aug 14;290(33):20117-27.Rhodopsin, the photoreceptor of rod cells, absorbs light to mediate the first step of vision by activating the G protein transducin (Gt). Several human diseases, such as retinitis pigmentosa or congenital night blindness, are linked to rhodopsin malfunctions. Most of the corresponding in vivo studies and structure-function analyses (e.g. based on protein x-ray crystallography or spectroscopy) have been carried out on murine or bovine rhodopsin. Because these rhodopsins differ at several amino acid positions from human rhodopsin, we conducted a comprehensive spectroscopic characterization of human rhodopsin in combination with molecular dynamics simulations. We show by FTIR and UV-visible difference spectroscopy that the light-induced transformations of the early photointermediates are very similar. Significant differences between the pigments appear with formation of the still inactive Meta I state and the transition to active Meta II. However, the conformation of Meta II and its activity toward the G protein are essentially the same, presumably reflecting the evolutionary pressure under which the active state has developed. Altogether, our results show that although the basic activation pathways of human and bovine rhodopsin are similar, structural deviations exist in the inactive conformation and during receptor activation, even between closely related rhodopsins. These differences between the well studied bovine or murine rhodopsins and human rhodopsin have to be taken into account when the influence of point mutations on the activation pathway of human rhodopsin are investigated using the bovine or murine rhodopsin template sequences.
- ArticleYang T, Wang Y, Ni D, Cheng D, Wang Y.Opt Express. 2022 May 23;30(11):20117-20134.Holographic optical element (HOE) can be used in many areas in optics due to its characteristics of thin structure, flexible wavefront reconstruction/control ability and angular/wavelength selectivity. In this paper, we propose a design method of off-axis reflective imaging systems based on freeform HOEs, which are fabricated by freeform wavefronts. The freeform HOEs offer many degrees of design freedom and can correct the aberrations in nonsymmetric imaging systems. The initial imaging system with freeform HOEs is generated using a point-by-point design approach, and is used for the preliminary design of the imaging system and the freeform recording system of each HOE. Then a joint optimization is conducted for all the systems, simultaneously considering the imaging performance, the diffraction efficiency, the system constraints and fabrication to get the final design results. To validate the feasibility and effectiveness of the proposed method, an off-axis reflective head-up display system with good performance based on freeform HOEs is designed and fabricated. Detailed procedures of the design and development process of the prototype are demonstrated.
- ArticlePristinski D, Le Ru EC, Tan S, Sukhishvili S, Du H.Opt Express. 2008 Nov 24;16(24):20117-25.Light refraction at the planar boundary of dielectric media prevents light propagation in the higher refractive index medium at angles beyond the critical value. This limitation is lifted when the evanescent wave is excited at the lower refractive index side of the interface. In this work we quantify polarization and angle dependence of surface-enhanced Raman scattering (SERS) intensity beyond the critical angle. Specifically, Raman spectra of thiocyanate molecules adsorbed on clustered silver nanoparticles at the water-glass interface were acquired using evanescent excitation and detection. Detected SERS signal polarization and scattering angle dependence are shown to be in agreement with a simple model based on excitation and radiation of a classical dipole near a lossless interface.