16 research outputs found

    Pneumatic Displacement of a Dense Sub-inner Limiting Membrane Pre-macular Hemorrhage in Dengue Maculopathy: A Novel Treatment Approach

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    Sub-inner limiting membrane (ILM) hemorrhage is a rare presenting feature of dengue maculopathy. A 24-year-old man in active military service who was recently treated for dengue hemorrhagic fever presented with sub-ILM bleeding in right eye (dominant eye) with profound diminution of vision. Spectral domain optical coherence tomography and fundus fluorescein angiography confirmed sub-ILM hemorrhage with no evidence of vasculitis/venous occlusion or neovascularization. He refused active surgical management by pars plana vitrectomy and was treated with pneumatic tamponade of C3F8 (100%) gas with prone positioning in order to achieve faster visual recovery. He responded well to treatment with complete visual recovery in 1 week. This case report documents for the first time treatment of sub-ILM hemorrhage in the premacular area with pneumatic tamponade in prone position leading to rapid and complete visual recovery in a patient with dengue maculopathy. This novel approach can be employed for patients who are ineligible for more active surgical management

    Antibacterial efficacy of Jackfruit rag extract against clinically important pathogens and validation of its antimicrobial activity in Shigella dysenteriae infected Drosophila melanogaster infection model

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    513-522Exploration of alternative sources of antibacterial compounds is an important and possibly an effective solution to the current challenges in antimicrobial therapy. Plant derived wastes may offer one such alternative. Here, we investigated the antibacterial property of extract derived from a part of the Jackfruit (Artocarpus heterophyllus Lam.) called ‘rag’, generally considered as fruit waste. Morpho-physical characterization of the Jackfruit rag extract (JFRE) was performed using Gas-chromatography, where peaks indicative of furfural; pentanoic acid; and hexadecanoic acid were observed. In vitro biocompatibility of JFRE was performed using the MTT assay, which showed comparable cellular viability between extract-treated and untreated mouse fibroblast cells. Agar well disc diffusion assay exhibited JFRE induced zones of inhibition for a wide variety of laboratory and clinical strains of Gram-positive and Gram-negative bacteria. Analysis of electron microscope images of bacterial cells suggests that JFRE induces cell death by disintegration of the bacterial cell wall and precipitating intracytoplasmic clumping. The antibacterial activity of the JFREs was further validated in vivo using Shigella dysenteriae infected fly model, where JFRE pre-fed flies infected with S. dysenteriae had significantly reduced mortality compared to controls. JFRE demonstrates broad antibacterial property, both in vitro and in vivo, possibly by its activity on bacterial cell wall

    Change in subfoveal choroidal thickness in diabetes and in various grades of diabetic retinopathy

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    Abstract Background To evaluate subfoveal choroidal thickness (SFCT) change in diabetes and in various grades of diabetic retinopathy (DR) in comparison to age-matched healthy subjects. Methods This prospective observational study included 100 eyes of diabetic patients without DR (group D), 100 eyes with DR (group R), and 100 eyes of healthy subjects (group N). The assessment included demographics, duration of diabetes, comprehensive ocular examination, fundus photography with/without fundus fluorescein angiography, spectral domain optical coherence tomography with enhanced depth imaging to assess SFCT. Results The SFCT was comparable between groups N (310.65 ± 37.34 µm) and D (308.48 ± 30.06 µm; P = 0.60), but was significantly lower in R (296.52 ± 21.41 µm; P < 0.01). The SFCT was significantly lower in proliferative DR (n = 36; SFCT = 284.56 ± 21.09 µm) as compared to non-proliferative DR (n = 64; SFCT = 303.25 ± 18.59 µm; P < 0.001). The SFCT had moderately negative correlation with severity of DR (R = − 0.50; P < 0.01). The difference in SFCT when compared with normal subjects was significant only in severe/very severe non-proliferative DR (294.47 ± 15.65 µm; P < 0.01) and in proliferative DR (284.56 ± 21.09 µm; P < 0.01). There was a negative correlation of SFCT with the duration of diabetes (R = − 0.41; P < 0.01). Conclusion SFCT decreases with increasing duration of diabetes. The decrease is significant after the onset of severe DR, and is proportionate to the severity of DR

    Enhancing the Electronic Properties and Stability of High-EfficiencyTin-Lead Mixed Halide Perovskite Solar Cells via DopingEngineering

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    Overcoming Voc loss to increase the efficiency of perovskite solar cells (PSCs) has been aggressively studied. In this work, we introduce and compare rubidium iodide (RbI) and potassium iodide (KI) alkali metal halides (AMHs) as dopants in a tin–lead (SnPb)-based perovskite system to improve the performance of PSCs by enhancing their Voc. Improvement in terms of surface morphology, crystallinity, charge transfer, and carrier transport in the SnPb perovskites was observed with the addition of AMH dopants. Significant power conversion efficiency improvement has been achieved with the incorporation of either dopant, and the highest efficiency was 21.04% in SnPb mixed halide PSCs when the RbI dopant was employed. In conclusion, we can outline the enhancement strategy that yields a remarkable efficiency of >20% with a smaller Voc loss and improved storage, light, and thermal stability in SnPb PSCs via doping engineering

    Common Metabolites in Two Different Hypertensive Mouse Models: A Serum and Urine Metabolome Study

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    Recent metabolomics studies have identified a wide array of microbial metabolites and metabolite pathways that are significantly altered in hypertension. However, whether these metabolites play an active role in pathogenesis of hypertension or are altered because of this has yet to be determined. In the current study, we hypothesized that metabolite changes common between hypertension models may unify hypertension’s pathophysiology with respect to metabolites. We utilized two common mouse models of experimental hypertension: L-arginine methyl ester hydrochloride (L-NAME)/high-salt-diet-induced hypertension (LSHTN) and angiotensin II induced hypertension (AHTN). To identify common metabolites that were altered across both models, we performed untargeted global metabolomics analysis in serum and urine and the resulting data were analyzed using MetaboAnalyst software and compared to control mice. A total of 41 serum metabolites were identified as being significantly altered in any hypertensive model compared to the controls. Of these compounds, 14 were commonly changed in both hypertensive groups, with 4 significantly increased and 10 significantly decreased. In the urine, six metabolites were significantly altered in any hypertensive group with respect to the control; however, none of them were common between the hypertensive groups. These findings demonstrate that a modest, but potentially important, number of serum metabolites are commonly altered between experimental hypertension models. Further studies of the newly identified metabolites from this untargeted metabolomics analysis may lead to a greater understanding of the association between gut dysbiosis and hypertension

    High-Efficiency Lead-Free Wide Band Gap Perovskite Solar Cells via Guanidinium Bromide Incorporation

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    Despite lead halide perovskite(top)/silicon(bottom) tandem solar cell achieving >29% efficiency, the toxicity of lead limits the adoption of perovskites in electronic devices. To solve this problem, tin perovskite has been suggested as an alternative candidate to be used as the top cell. However, most of the reports on tin perovskite solar cells are based on narrow band gap materials (band gap: 1.20–1.40 eV), which are not suitable to be used as the tandem top cell. In addition, the efficiency of the previously reported wide band gap lead-free perovskites is not satisfactory, shown to be less than 2.00%. This study explores the fabrication of the wide band gap (1.61 eV) ASnI2Br perovskite solar cells through the optimization of formamidinium and guanidinium content to improve the efficiency from 1.68 to 7.00%. Substituting the A site with larger cation results in a larger crystal size, which translated into higher device stability. Better energy-level alignment within the device significantly enhanced the charge injection and extraction, which translated into higher open-circuit voltage. This work provides proof that tin-halide perovskite solar cells have the potential in the fabrication of lead-free all-perovskite tandem solar cells.This research was supported by JST Mirai Program (JPMJMI17EA) and the Chinese Scholarship Council (CSC202008050034)

    SnOx as Bottom Hole Extraction Layer and Top In Situ Protection Layer Yields over 14% Efficiency in Sn-Based Perovskite Solar Cells

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    Sn-based perovskite solar cells (S-PSCs) are a promising candidate to replace toxic Pb-based PSCs. For promoting their industrial application, developing inorganic substitutions of unstable poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is also an important part due to its intrinsic stability and low cost. Here, we in situ prepared ambipolar SnOx by a simple and fast plasma-assistant strategy (P-SnOx). The as-prepared P-SnOx works as a hole transport layer directly, yielding a 10.89 +/- 0.51% power conversion efficiency (PCE) comparable to a PEDOT:PSS-based device (10.39 +/- 0.72%). The top SnOx (T-SnOx), composed of SnO2 and Sn metal, as a modifier and a protection layer of the perovskite by reducing Sn4+ to Sn2+, gives a 13.08 +/- 0.33% device performance. This in situ top protective strategy combined with P-SnOx as a hole transport layer further boosts the champion PCE of S-PSCs to 14.09% (13.5 +/- 0.32%)

    SnOx as Bottom Hole Extraction Layer and Top In Situ Protection Layer Yields over 14% Efficiency in Sn-Based Perovskite Solar Cells

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    Sn-based perovskite solar cells (S-PSCs) are a promising candidate to replace toxic Pb-based PSCs. For promoting their industrial application, developing inorganic substitutions of unstable poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is also an important part due to its intrinsic stability and low cost. Here, we in situ prepared ambipolar SnOx by a simple and fast plasma-assistant strategy (P-SnOx). The as-prepared P-SnOx works as a hole transport layer directly, yielding a 10.89 +/- 0.51% power conversion efficiency (PCE) comparable to a PEDOT:PSS-based device (10.39 +/- 0.72%). The top SnOx (T-SnOx), composed of SnO2 and Sn metal, as a modifier and a protection layer of the perovskite by reducing Sn4+ to Sn2+, gives a 13.08 +/- 0.33% device performance. This in situ top protective strategy combined with P-SnOx as a hole transport layer further boosts the champion PCE of S-PSCs to 14.09% (13.5 +/- 0.32%)

    Large Grain Growth and Energy Alignment Optimization by Diethylammonium Iodide Substitution at A Site in Lead-Free Tin Halide Perovskite Solar Cells

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    Environment-friendly tin perovskite solar cells (T-PKSCs) are the most suitable alternative candidate for lead-free PKSCs. However, the photovoltaic performance of such T-PKSCs is far below those of lead-based perovskite solar cells due to an energetic mismatch between the perovskite layer and charge transport layers. Herein, it is shown that, by partial substitution of the A-site cation using diethylammonium iodide (DEAI) substitution, deeper energy levels are obtained. At the same time, the trap density is reduced and the grain size is significantly improved. The fabricated solar cell shows much enhanced efficiency from 7.31% to 10.28%, short-circuit current density from 18.68 to 21.69 mA cm−2, open-circuit voltage from 0.59 to 0.67 V, and fill factor from 0.67 to 0.71 after DEAI substitution. Such an efficiency improvement can be explained by matching energy levels at the interfaces between perovskite layer and the charge transport layers. In addition, after 50 days of storage, the modified T-PKSCs demonstrate high stability maintaining 78% of its initial efficiency, whereas the reference device degrades to 68% during 28 days storage
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