17,713 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

    Proton Spin Content From Lattice QCD

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    We calculate the form factor of the quark energy momentum tensor and thereby extract the quark orbital angular momentum of the nucleon. The calculation is done on a quenched 163×2416^3 \times 24 lattice at β=6.0\beta = 6.0 and with Wilson fermions at κ\kappa = 0.148, 0.152, 0.154 and 0.155. We calculate the disconnected insertion stochastically which employs the Z2Z_2 noise with an unbiased subtraction. This proves to be an efficient method of reduce the error from the noise. We find that the total quark contribution to the proton spin is 0.29±0.070.29 \pm 0.07. From this we deduce that the quark orbital angular momentum is 0.17±0.080.17 \pm 0.08 and predict the gluon spin to be 0.21±0.070.21 \pm 0.07, i.e. about 40% of the proton spin is due to the glue.Comment: LATTICE99(Matrix Elements), 3 pages, 3 figure

    Equivalent Circuit Models for Optical Amplifiers

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    Research on vibration-isolating rate of vibration-isolating slot under buried pipe subjected to blasting seismic waves

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    The vibration-isolating rate of vibration isolating slot under buried pipe subjected to blasting seismic waves can been investigated by using the numerical method. For achieving a good vibration isolating effect, the depth of the vibration-isolating slot needs to be larger with the increase of the depth of the pore. The difference of the super-depth h leads to the difference in the trend of vibration isolating. The depth of the vibration-isolating slot is larger than the depth of the hole, which can improve the vibration-isolating rate. The different type of rock and soil medium is a significant effect on the vibration-isolating rate. To obtain ideal vibration-isolating effect, vibration-isolating slot depth compared with pipeline buried depth is greater than a certain value

    Effects of Low-Level Laser Therapy and Eccentric Exercises in the Treatment of Patellar Tendinopathy

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    The study aims to investigate if low-level laser therapy (LLLT) combined with eccentric exercises could more effectively treat patellar tendinopathy than LLLT alone and eccentric exercises alone. Twenty-one patients with patellar tendinopathy were randomized to three groups: laser alone, exercise alone, or laser plus exercise, with seven in each group. Laser irradiations were administered at the inferior pole of the patella and the two acupoints of Extra 36 (Xiyan) with the intensity of 1592 mW/cm2. Eccentric training program consisted of three sets of 15 repetitions of unilateral squat on level ground. All patients received six treatments per week for four weeks. Knee pain and function and quadriceps muscle strength and endurance were evaluated at baseline and the end of treatment. After the 4-week intervention, all groups showed significant improvements in all the outcomes (P<0.01). The laser + exercise group had significantly greater improvements in all the outcomes than the other two groups (P<0.05), except nonsignificant difference in pain relief between the laser + exercise group and the laser group. In conclusion, LLLT combined with eccentric exercises is superior to LLLT alone and eccentric exercises alone to reduce pain and improve function in patients with patellar tendinopathy

    2-Phenyl­imidazolium acetate

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    There are two 2-phenyl­imidazole cations and two acetate anions in the asymmetric unit of the title mol­ecular salt, C9H9N2 +·C2H3O2 −. The dihredral angles between the five- and six-membered rings are 5.50 (2) and 6.90 (2)° in the two molecules. The structure is stabilized by N—H⋯O and weak C—H⋯O hydrogen-bonding inter­actions between the cations and anions, resulting in chains propagating in [110]
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