2,268 research outputs found

    Deep spectral learning for label-free optical imaging oximetry with uncertainty quantification

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    Measurement of blood oxygen saturation (sO2) by optical imaging oximetry provides invaluable insight into local tissue functions and metabolism. Despite different embodiments and modalities, all label-free optical-imaging oximetry techniques utilize the same principle of sO2-dependent spectral contrast from haemoglobin. Traditional approaches for quantifying sO2 often rely on analytical models that are fitted by the spectral measurements. These approaches in practice suffer from uncertainties due to biological variability, tissue geometry, light scattering, systemic spectral bias, and variations in the experimental conditions. Here, we propose a new data-driven approach, termed deep spectral learning (DSL), to achieve oximetry that is highly robust to experimental variations and, more importantly, able to provide uncertainty quantification for each sO2 prediction. To demonstrate the robustness and generalizability of DSL, we analyse data from two visible light optical coherence tomography (vis-OCT) setups across two separate in vivo experiments on rat retinas. Predictions made by DSL are highly adaptive to experimental variabilities as well as the depth-dependent backscattering spectra. Two neural-network-based models are tested and compared with the traditional least-squares fitting (LSF) method. The DSL-predicted sO2 shows significantly lower mean-square errors than those of the LSF. For the first time, we have demonstrated en face maps of retinal oximetry along with a pixel-wise confidence assessment. Our DSL overcomes several limitations of traditional approaches and provides a more flexible, robust, and reliable deep learning approach for in vivo non-invasive label-free optical oximetry.R01 CA224911 - NCI NIH HHS; R01 CA232015 - NCI NIH HHS; R01 NS108464 - NINDS NIH HHS; R21 EY029412 - NEI NIH HHSAccepted manuscrip

    First born model for reflection-mode Fourier ptychographic microscopy

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    We validate a first Born approximation based model for Reflection-mode Fourier ptychography under the semi-infinite boundary condition. Our model enables optical thickness and absorption recovery with enhanced resolution from thin samples.Published versio

    Inverse scattering for reflection intensity phase microscopy

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    Reflection phase imaging provides label-free, high-resolution characterization of biological samples, typically using interferometric-based techniques. Here, we investigate reflection phase microscopy from intensity-only measurements under diverse illumination. We evaluate the forward and inverse scattering model based on the first Born approximation for imaging scattering objects above a glass slide. Under this design, the measured field combines linear forward-scattering and height-dependent nonlinear back-scattering from the object that complicates object phase recovery. Using only the forward-scattering, we derive a linear inverse scattering model and evaluate this model's validity range in simulation and experiment using a standard reflection microscope modified with a programmable light source. Our method provides enhanced contrast of thin, weakly scattering samples that complement transmission techniques. This model provides a promising development for creating simplified intensity-based reflection quantitative phase imaging systems easily adoptable for biological research.https://arxiv.org/abs/1912.07709Accepted manuscrip

    Chronic stress induces steatohepatitis while decreases visceral fat mass in mice

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    BACKGROUND: Prolonged stress leads over time to allostatic load on the body and is likely to exacerbate a disease process. Long-term of stress exposure is one of a risk factor for metabolism-related diseases such as obesity and type 2 diabetes. However, the relationship between chronic stress and non-alcoholic fatty liver disease (NAFLD) remain unknown. METHODS: To address the hypothesis that chronic stress associate to NAFLD development, we subjected C57bl/6 mice to electric foot shock and restraint stress for 12 weeks to set up chronic stress model. Then the serum and hepatic triglyceride (TG), total cholesterol (TC) were measured. Hepatic HE and Oil red O staining were used to specify the state of the NAFLD. To investigate whether inflammation takes part in the stress-induced NAFLD process, related visceral fat, serum and hepatic inflammatory factors were measured. RESULTS: We observed that chronic stress led to an overall increase of hepatic triglyceride and cholesterol while decreasing body weight and visceral fat mass. Microvesicular steatosis, lobular inflammation and ballooning degeneration were seen in stress liver section. This effect was correlated with elevated hepatic and serum inflammatory factors. Although the amount of visceral fat was decreased in stress group, various adipocytokines were elevated. CONCLUSIONS: We showed that chronic stress is associated to NAFLD and chronic inflammation in visceral fat, though food intake and visceral fat mass were decreased. These results may contribute to better understanding of the mechanism from steatosis to steatohepatitis, and propose a novel insight into the prevention and treatment of NAFLD

    Comparative analysis of the secretomes of Schizophyllum commune and other wood-decay basidiomycetes during solid-state fermentation reveals its unique lignocellulose-degrading enzyme system

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    Additional file 3: Table S2. Identified proteins in the secretomes of four fungi during SSF on Jerusalem artichoke stalk

    Tris(dibenzoyl­methanido-κ2 O,O′)[(6R,8R)-(−)-7,7-dimethyl-3-(2-pyrid­yl)-5,6,7,8-tetra­hydro-6,8-methano­isoquinoline-κ2 N,N′]terbium(III)

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    In the title compound, [Tb(C15H11O2)3(C17H18N2)], the 7,7-dimethyl-3-(2-pyrid­yl)-5,6,7,8-tetra­hydro-6,8-methano­iso­quin­oline (LRR) ligand coordinates to TbIII through the two N atoms of the heterocycle. The metal centre is also chelated by three deprotonated 1,3-diphenyl­propane-1,3-dione (dbm) ligands, forming enanti­omerically pure [Tb(dbm)3 LRR]. The TbIII atom is located in a distorted square anti­prism of eight coordinating atoms (six O and two N atoms)

    Metabolic syndrome and chronic kidney disease in general Chinese adults: Results from the 2007–08 China National Diabetes and Metabolic Disorders Study

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    AbstractBackgroundChina is undergoing a rapid transition to an urbanized and Western diet pattern, which worsens the public health burden of metabolic syndrome (MS) and chronic kidney disease (CKD). We aimed to estimate the prevalence of CKD among adults with MS and to evaluate the association between MS and CKD in China.MethodsThe data were obtained from the China National Diabetes and Metabolic Disorders Study conducted from June 2007 to May 2008. A total of 15,987 individuals aged 20y or older were included as study participants.ResultsAge-standardized prevalence of CKD, which was defined as a glomerular filtration rate <60ml/min/1.73m2, in participants with and without MS was 4.64% and 3.30%, respectively. The multivariate-adjusted odds ratio of CKD associated with MS was 1.495 (95% CI: 1.190–1.879). Elevated blood pressure, elevated fasting glucose, elevated triglycerides, and reduced high-density lipoprotein cholesterol had statistically significant increased odds ratios of 1.218, 1.256, 1.325 and 1.797 for CKD, respectively, while elevated waist circumference was not significantly associated with an increased odds ratio of CKD.ConclusionsOur study suggests an increasing prevalence of CKD among Chinese adults with MS and a strong association between CKD and MS
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