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Photoreceptor Progenitors Depend Upon Coordination of <i>gdf6a</i> , <i>thrβ</i> , and <i>tbx2b</i> to Generate Precise Populations of Cone Photoreceptor Subtypes
摘要： PURPOSE. Replacing cone photoreceptors, the units of the retina necessary for daytime vision, depends upon the successful production of a full variety of new cones from, for example, stem cells. Using genetic experiments in a model organism with high cone diversity, zebrafish, we map the intersecting effects of cone development factors gdf6a, tbx2b, and thrb. METHODS. We investigated these genes of interest by using genetic combinations of mutants, gene knockdown, and dominant negative gene expression, and then quantified cone subtype outcomes (which normally develop in tightly regulated ratios). RESULTS. Gdf6a mutants have reduced blue cones and, discovered here, reduced red cones. In combined gdf6a/tbx2b disruption, the loss of gdf6a in heterozygous tbx2b mutants reduced UV cones. Intriguingly, when we disrupted thrb in gdf6a mutants by using a thrb morpholino, their combined early disruption revealed a lamination phenotype. Disrupting thrb activity via expression of a dominant negative thrb (dnthrb) at either early or late retinal development had differential outcomes on red cones (reduced abundance), versus UV and blue cones (increased abundance). By using dnthrb in gdf6a mutants, we revealed that disrupting thrb activity did not change gdf6a mutant cone phenotypes. CONCLUSIONS. Gdf6a loss directly affects blue and red cones and indirectly affects UV cones by increasing sensitivity to additional disruption, such as reduced tbx2b, resulting in fewer UV cones. The effects of thrb change through photoreceptor development, first promoting red cones and restricting UV cones, and later restricting UV and blue cones. The effects of gdf6a on UV, blue, and red cone development overlap with, but likely supersede, those of thrb.
关键词： BMP signaling,progenitor,color vision,retinal lamination,thyroid signaling,zebrafish,retinal development,determination,regeneration,cone photoreceptor
更新于2025-09-19 17:15:36
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Retrieval of the Fine-Mode Aerosol Optical Depth over East China Using a Grouped Residual Error Sorting (GRES) Method from Multi-Angle and Polarized Satellite Data
摘要： The ?ne-mode aerosol optical depth (AODf) is an important parameter for the environment and climate change study, which mainly represents the anthropogenic aerosols component. The Polarization and Anisotropy of Re?ectances for Atmospheric Science coupled with Observations from a Lidar (PARASOL) instrument can detect polarized signal from multi-angle observation and the polarized signal mainly comes from the radiation contribution of the ?ne-mode aerosols, which provides an opportunity to obtain AODf directly. However, the currently operational algorithm of Laboratoire d’Optique Atmosphérique (LOA) has a poor AODf retrieval accuracy over East China on high aerosol loading days. This study focused on solving this issue and proposed a grouped residual error sorting (GRES) method to determine the optimal aerosol model in AODf retrieval using the traditional look-up table (LUT) approach and then the AODf retrieval accuracy over East China was improved. The comparisons between the GRES retrieved and the Aerosol Robotic Network (AERONET) ground-based AODf at Beijing, Xianghe, Taihu and Hong_Kong_PolyU sites produced high correlation coef?cients (r) of 0.900, 0.933, 0.957 and 0.968, respectively. The comparisons of the GRES retrieved AODf and PARASOL AODf product with those of the AERONET observations produced a mean absolute error (MAE) of 0.054 versus 0.104 on high aerosol loading days (AERONET mean AODf at 865 nm = 0.283). An application using the GRES method for total AOD (AODt) retrieval also showed a good expandability for multi-angle aerosol retrieval of this method.
关键词： multi-angular remote sensing,?ne-mode aerosol optical depth,optimal aerosol model determination,PARASOL,polarized remote sensing
更新于2025-09-19 17:15:36
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A selective and sensitive azido near-infrared fluorescent probe for tris(2-carboxyethyl)phosphine quantitative detection and its application for <i>E. coli</i> determination
摘要： We developed a sensitive near-infrared fluorescent probe, azido hemicyanine (HC-N3), for the detection of tris(2-carboxyethyl)phosphine (TCEP) with the lowest LOD (92 nM) so far. HC-N3 has good selectivity for TCEP among thiols and 20 kinds of natural amino acid. The quantification of E. coli (101–103 cfu mL?1) demonstrated its practicability in complicated biosystems.
关键词： E. coli determination,near-infrared fluorescent probe,selectivity,sensitivity,TCEP detection
更新于2025-09-19 17:15:36
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Chlorine and sulfur determination in water using indirect laser-induced breakdown spectroscopy
摘要： The detection sensitivity of chlorine (Cl) and sulfur (S) elements is poor using direct laser-induced breakdown spectroscopy (LIBS) because of the high ionization energy of Cl and S. Therefore, a new technique, namely indirect laser-induced breakdown spectroscopy (ID-LIBS), was proposed to improve the detection sensitivity of Cl and S elements. The method detected Cl in water by indirectly detecting the excess silver (Ag) after the precipitation reaction of Ag and chloride. Similarly, the method indirectly detected S in water by detecting the excess barium (Ba) after the precipitation reaction of Ba and sulfate, due to Ag and Ba with low ionization energy and easy excitation. The lines of Ag I 546.5 nm and Ba I 553.5 nm were detected. The R2 values of 0.999 and 0.997 were obtained for Cl and S, respectively. The limit of quantitation (LoQ) was 2 mg/L for Cl and 5 mg/L for S. The detection sensitivity was improved by about three orders of magnitude compared to using Cl I 822.17 nm and S I 921.28 nm. The results showed that the technique of indirect LIBS can achieve the sensitive detection of Cl and S in water indicating that the technique has tremendous potential for element analysis of water.
关键词： Indirect LIBS,Water analysis,Laser-induced breakdown spectroscopy,Determination
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on Communication and Electronics Systems (ICCES) - Coimbatore, India (2019.7.17-2019.7.19)] 2019 International Conference on Communication and Electronics Systems (ICCES) - Saturation Optimization and Extrinsic Timing Analysis for Optically Controlled GFET
摘要： We propose a generative model for robust tensor factorization in the presence of both missing data and outliers. The objective is to explicitly infer the underlying low-CANDECOMP/PARAFAC (CP)-rank tensor capturing the global information and a sparse tensor capturing the local information (also considered as outliers), thus providing the robust predictive distribution over missing entries. The low-CP-rank tensor is modeled by multilinear interactions between multiple latent factors on which the column sparsity is enforced by a hierarchical prior, while the sparse tensor is modeled by a hierarchical view of Student-t distribution that associates an individual hyperparameter with each element independently. For model inference under a fully Bayesian treatment, which can effectively prevent the overfitting problem and scales linearly with data size. In contrast to existing related works, our method can perform model selection automatically and implicitly without the need of tuning parameters. More specifically, it can discover the groundtruth of CP rank and automatically adapt the sparsity inducing priors to various types of outliers. In addition, the tradeoff between the low-rank approximation and the sparse representation can be optimized in the sense of maximum model evidence. The extensive experiments and comparisons with many state-of-the-art algorithms on both synthetic and real-world data sets demonstrate the superiorities of our method from several perspectives.
关键词： tensor factorization,video background modeling,variational Bayesian (VB) inference,tensor completion,Rank determination,robust factorization
更新于2025-09-19 17:13:59
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[Laser Institute of America ICALEO? 2017: 36th International Congress on Applications of Lasers & Electro-Optics - Atlanta, Georgia, USA (October 22–26, 2017)] International Congress on Applications of Lasers & Electro-Optics - Influence of vapor on hyperspectral imaging for monitoring laser-based material processing
摘要： In this paper a further characterization of hyperspectral imaging (HSI) system that we developed is presented. This camera-based system is meant to be used for temperature determination in laser-based material processing. It comprises a high-speed camera and a self-developed HSI-lens system. It offers a time resolution in the μs-range and a spectral resolution of ~4 nm. In HSI spatial and spectral information upon the object/process to be investigated can be acquired simultaneously. The spectral information reveals spectral features of the process itself and it is used to derive temperature information. For temperature determination, the process emissions are considered to be black/gray-body radiation. Based upon very promising initial HSI results, we present and discuss further HSI-derived observations of the laser-beam welding process within this paper. These results include temperature information as well as spectral characteristics. In addition, simultaneous high-speed camera observations were conducted and the results were connected with HSI-derived findings. This way, the influence of vapor on the measurement is evaluated and the HSI-technique is validated to be beneficial in monitoring laser-based material processing.
关键词： hyperspectral imaging,laser-based material processing,vapor influence,temperature determination,high-speed camera
更新于2025-09-16 10:30:52
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Virus Structures by X-Ray Free-Electron Lasers
摘要： Until recently X-ray crystallography has been the standard technique for virus structure determinations. Available X-ray sources have continuously improved over the decades, leading to the realization of X-ray free-electron lasers (XFELs). They provide high-intensity femtosecond X-ray pulses, which allow for new kinds of experiments by making use of the diffraction-before-destruction principle. By overcoming classical dose constraints, they at least in principle allow researchers to perform X-ray virus structure determination for single particles at room temperature. Simultaneously, the availability of XFELs led to the development of the method of serial femtosecond crystallography, where a crystal structure is determined from the measurement of hundreds to thousands of microcrystals. In the case of virus crystallography this method does not require freezing of the crystals and allows researchers to perform experiments under non-equilibrium conditions (e.g., by laser-induced temperature jumps or rapid chemical mixing), which is currently not possible with electron microscopy.
关键词： structure determination,serial crystallography,XFEL,single particle imaging,virus crystallography,X-ray free-electron laser
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 28th International Symposium on Industrial Electronics (ISIE) - Vancouver, BC, Canada (2019.6.12-2019.6.14)] 2019 IEEE 28th International Symposium on Industrial Electronics (ISIE) - A study on the lifetime estimation of photovoltaic modules under accelerated environmental conditions
摘要： Lifetime estimation is critical for predicting the revenue of the photovoltaic (PV) plant to be built. Therefore it must be done before huge investments will be made to build and operate a PV plant. Since the degradation rate of PV modules features as a random variable, statistical models are commonly used to estimate the lifetime of PV modules. However, most existing researches select the statistical model to describe the degradation rate of PV modules empirically, and lack of basis. In this paper we propose a practical procedure for selecting the statistical model which describes the degradation rate of PV modules best. Based on the selected model, the lifetime of PV modules is estimated. We use probability plots and hypothesis tests to validate the distributional assumptions. Then we use negative log-likelihood values to further determine the distribution that describes the lifetimes best. Three classical distributions, i.e., Weibull, lognormal and exponential distributions, are considered. The life distributions at different stress levels are assumed to come from the same parametric family. Based on the assumption, the parameters of the hypothesized distributions are estimated using maximum likelihood estimation methods. It is found that the PV lifetimes follow a parametric location-scale distribution family, and they follow the Weibull distribution best. The conclusion is realistic from a physical point of view.
关键词： accelerated tests,photovoltaic modules,statistical models,distribution determination,lifetime estimation
更新于2025-09-16 10:30:52
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UV-LED fluence determination by numerical method for microbial inactivation studies
摘要： The Ultraviolet Light-Emitting Diode (UV-LED) is a new UV source suitable for small to mid-size water disinfection units. The design of a UV-LED reactor entails the integration of hydrodynamics, radiation, and kinetics data. The kinetics of microbial inactivation are necessary for UV-LED reactor design and the determination of kinetic rate constants depends on the accuracy of fluence rate measurement. However, there is not an easy way to measure the fluence rate inside a solution. In this study, a computational method is proposed to calculate irradiance and fluence rate based on the LED’s relative radiation profile and its radiant power, which are two standard pieces of information available in an LED’s datasheet. UV-LED was modeled as a polychromatic point source with a specific radiation profile and the fluence rate was calculated by solving the Radiative Transfer Equation by considering the refraction, reflection, and absorption of the medium. The irradiance and fluence rate predictions on the surface of the water were evaluated successfully by radiometry and actinometry measurements, respectively. The fluence rate imposed by 265-nm UV-LED and 275-nm UV-LED in Petri dishes with internal diameters of 5 cm and 9 cm were measured using biodosimetry with E. coli and MS2, when the UV-LED germicidal factor was obtained by considering the LED emission spectrum and the microorganism action spectra. Biodosimetry experiments using E. coli and MS2 at exposure times over 200 seconds indicated a close agreement between the simulation and experimental data. Such results are indicating the kinetic rate constants of a microorganism can be estimated without performing kinetic study using the action spectrum of microorganisms. Further, the results showed the proposed method can be applied for fluence rate determination for any LED’s radiation profile, LED position, and the experimental apparatus’s regardless of the availability of the action spectrum of microorganisms.
关键词： kinetic rate constant,polychromatic,fluence determination,UV-LED,irradiation model
更新于2025-09-16 10:30:52
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Design and optimization of a single-use optical sensor based on a polymer inclusion membrane for zinc determination in drinks, food supplement and foot health care products
摘要： A single-use optical sensor was designed for Zn(II) determination based on the immobilisation of the colorimetric reagent 2-acetylpyridine benzoylhydrazone (2-APBH) in a polymer inclusion membrane (PIM) adhered on the surface of an inert rectangular strip of polyester (Mylar). Different components for the membrane preparation were tested and those resulting in membrane with good appearance, proper physical and optical properties and ease of preparation were selected. Factorial design 23 with three replicates of the central point was applied for the optimisation of the membrane composition. The optimal composition consisted of 2.5 g of poly(vinyl chloride) (PVC), 4 mL of tributyl phosphate (TBP) and 0.04 g of 2-APBH. The optode showed a linear dynamic range from 0.03 (detection limit) to 1 mg L-1 of Zn(II) ions with a response time of 30 min in aqueous solution at pH 6 and a relative standard deviation of 3.90% for 0.4 mg L-1 of Zn(II). The sensor exhibited good selectivity to Zn(II) over other commonly ions. It was successfully applied to the determination of Zn(II) in a water certified reference material, spiked tap water, vitamin-mineral drink, food supplement and foot health care products, as contribution to the concern about this heavy metal due to its significant role in many biological and physiological processes although toxicant at high doses.
关键词： 2-acetylpyridine benzoylhydrazone,Zn(II) ions determination,optical sensor,PVC matrix,polymer inclusion membrane
更新于2025-09-16 10:30:52