Graphics processing unit accelerating compressed sensing photoacoustic computed tomography with total variation

Photoacoustic computed tomography with compressed sensing (CS-PACT) is a commonly used imaging strategy for sparse-sampling PACT. However, it is very time-consuming because of the iterative process involved in the image reconstruction. In this paper, we present a graphics processing unit (GPU)-based parallel computation framework for total-variation-based CS-PACT and adapted into a custom-made PACT system. Specifically, five compute-intensive operators are extracted from the iteration algorithm and are redesigned for parallel performance on a GPU. We achieved an image reconstruction speed 24–31 times faster than the CPU performance. We performed in vivo experiments on human hands to verify the feasibility of our developed method

Temporal variations in ambient air quality indicators in Shanghai municipality, China

© 2020, The Author(s). Official data on daily PM2.5, PM10, SO2, NO2, CO, and maximum 8-h average O3 (O3_8h) concentrations from January 2015 to December 2018 were evaluated and air pollution status and dynamics in Shanghai municipality were examined. Factors affecting air quality, including meteorological factors and socio-economic indicators, were analyzed. The main findings were that: (1) Overall air quality status in Shanghai municipality has improved and number of days meeting ‘Chinese ambient air quality standards’ (CAAQS) Grade II has increased. (2) The most frequent major pollutant in Shanghai municipality is O3 (which exceeded the standard on 110 days in 2015, 84 days in 2016, 126 days in 2017, 113 days in 2018), followed by PM2.5 (120days in 2015, 104 days in 2016, 67 days in 2017, 61 days in 2018) and NO2 (50 days in 2015, 67 days in 2016, 79 days in 2017, 63 days in 2018). (3) PM2.5 pollution in winter and O3 pollution in summer are the main air quality challenges in Shanghai municipality. (4) Statistical analysis suggested that PM2.5, PM10, SO2 and NO2 concentrations were significantly negatively associated with precipitation (Prec) and atmosphere temperature (T) (p < 0.05), while the O3 concentration was significantly positively associated with Prec and T (p < 0.05). Lower accumulation of PM, SO2, NO2, and CO and more serious O3 pollution were revealed during months with higher temperature and more precipitation in Shanghai. The correlation between the socio-economic factors and the air pollutants suggest that further rigorous measures are needed to control PM2.5 and that further studies are needed to identify O3 formation mechanisms and control strategies. The results provide scientific insights into meteorological factors and socio-economic indicators influencing air pollution in Shanghai.This study was supported by the Key Research Program of Frontier Sciences (Grant No. ZDBS-LY-7011), National Key Research and Development Program of China (2017YFF0207303; 2016YFC0503004). The online sharing of air quality data by the Shanghai Environmental Monitoring Center is gratefully acknowledged

Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.Engineering and Applied Science

Highly sensitive magnetic properties and large linear magnetoresistance in antiferromagnetic CrxSe(0.875\lex\le1)single crystals

CrxSe (x\le1) is a class of quasi-layered binary compounds with potential applications in spintronics due to its intriguing antiferromagnetic properties. In this work, CrxSe single crystals with high Cr content (x=0.87, 0.91 and 0.95) were grown, and their magnetic and transport properties were investigated in detail. It is found that with small increase of Cr content, the N\'eel temperature (TN) of the samples can dramatically increase from 147 K to 257 K, accompanied with obvious changes in the magnetic anisotropy and hysteresis. The phenomena of field-induced spin-flop transitions were unveiled in these alloys, indicating their comparatively low anisotropy. The magnetoresistance (MR) of the three compounds showed positive dependence at low temperatures and particularly, non-saturated linear positive MR was observed in Cr0.91Se and Cr0.95Se, with a large value of 16.2% achieved in Cr0.91Se (10K, 9T). The calculated Fermi surface and MR showed that the quasi-linear MR is a product of carrier compensation. Our work revealed highly sensitive magnetic and transport properties in the Cr-Se compounds, which can lay foundation when constructing further antiferromagnetic spintronic devices based on them

On-line near-infrared spectroscopy optimizing and monitoring biotransformation process of γ-aminobutyric acid

AbstractNear-infrared spectroscopy (NIRS) with its fast and nondestructive advantages can be qualified for the real-time quantitative analysis. This paper demonstrates that NIRS combined with partial least squares (PLS) regression can be used as a rapid analytical method to simultaneously quantify l-glutamic acid (l-Glu) and γ-aminobutyric acid (GABA) in a biotransformation process and to guide the optimization of production conditions when the merits of NIRS are combined with response surface methodology. The high performance liquid chromatography (HPLC) reference analysis was performed by the o-phthaldialdehyde pre-column derivatization. NIRS measurements of two batches of 141 samples were firstly analyzed by PLS with several spectral pre-processing methods. Compared with those of the HPLC reference analysis, the resulting determination coefficients (R2), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD) of the external validation for the l-Glu concentration were 99.5%, 1.62g/L, and 11.3, respectively. For the GABA concentration, R2, RMSEP, and RPD were 99.8%, 4.00g/L, and 16.4, respectively. This NIRS model was then used to optimize the biotransformation process through a Box-Behnken experimental design. Under the optimal conditions without pH adjustment, 200g/L l-Glu could be catalyzed by 7148 U/L glutamate decarboxylase (GAD) to GABA, reaching 99% conversion at the fifth hour. NIRS analysis provided timely information on the conversion from l-Glu to GABA. The results suggest that the NIRS model can not only be used for the routine profiling of enzymatic conversion, providing a simple and effective method of monitoring the biotransformation process of GABA, but also be considered to be an optimal tool to guide the optimization of production conditions

Chitosan-Templated Bio-coloration of Cotton Fabrics via Laccase-Catalyzed Polymerization of Hydroquinone

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.There is an increasing interest in the development of enzymatic coloration of textile fabrics as an alternative to conventional textile dyeing processes, which is successful for dyeing protein fibers. However, unmodified cotton fabrics are difficult to be dyed through enzyme catalysis due to the lack of affinity of biosynthesized dyes to cotton fibers. In order to improve the enzyme‐catalyzed dyeability of cotton fibers, chitosan was used to coat cotton fabrics as template. A novel and facile bio‐coloration technique using laccase catalysis of hydroquinone was developed to dye chitosan‐templated cotton fabrics. The polymerization of hydroquinone with the template of chitosan under the laccase catalysis was monitored by ultraviolet‐vis spectrophotometer on the absorbance of reaction solution. A significant peak of UV‐vis spectrum at 246 nm corresponding to large conjugated structures appeared and increased with increasing the duration of enzymatic catalysis. The effect of different treatment conditions on the laccase‐catalyzed dyeing of cotton fabric was investigated to determine their optimal parameters of laccase‐catalyzed coloration. Fourier‐transform infrared spectroscopy spectra demonstrated the formation of H‐bond and Schiff base reaction between chitosan and polymerized hydroquinone. Scanning electron microscopy indicated that the surface of dyed cotton fiber was much rougher than that of the control sample. Moreover, X‐ray photoelectron spectroscopy also revealed the existence of the chitosan/polymerized hydroquinone complex and polymerized hydroquinone on the dyed cotton fibers. This chitosan‐templated approach offers possibility for biological dyeing coloration of cotton fabrics and other cellulosic materials

Graphics processing unit accelerating compressed sensing photoacoustic computed tomography with total variation

Photoacoustic computed tomography with compressed sensing (CS-PACT) is a commonly used imaging strategy for sparse-sampling PACT. However, it is very time-consuming because of the iterative process involved in the image reconstruction. In this paper, we present a graphics processing unit (GPU)-based parallel computation framework for total-variation-based CS-PACT and adapted into a custom-made PACT system. Specifically, five compute-intensive operators are extracted from the iteration algorithm and are redesigned for parallel performance on a GPU. We achieved an image reconstruction speed 24–31 times faster than the CPU performance. We performed in vivo experiments on human hands to verify the feasibility of our developed method

Spatial dynamic simulation of beetles in biodiversity hotspots

IntroductionColeoptera is the most species-rich order of animals with the widest distribution area; however, little is known about its global suitability distribution, and a substantial number of species are experiencing silent extinction. Most of Earth’s biocommunities are concentrated in biodiversity hotspots, and these hotspots receive the largest investment of conservation funds. The survival of beetles is closely related to the richness of biodiversity, so habitat loss in hotspots results in a high extinction risk for beetles.MethodsWe used the MaxEnt model to simulate the spatial suitable distribution in six time periods (1970-1980, 1980-1990, 1990-2000, 2000-2010, 2010-2020, and 1970-2020). Furthermore, we determined the priority suitable regions in hotspots after coupling the current biodiversity zones and evaluated the congruence between the suitable habitat of beetles and hotspots.ResultsThe results revealed that less than 30% of suitable regions were located in hotspots, and approximately 49.08% of the suitable habitat remained constant in all six periods, and can be regarded as climatically stable refugia. The Mediterranean Basin had the largest suitable area in each period and was always ranked first; other regions, such as Indo-Burma, Irano-Anatolian, and Mesoamerica, also had large areas of suitable habitat. Nine excellent, ten stable, and seventeen lower hotspots were identified based on their dynamic changes in 36 hotspots.DiscussionBased on these results, corresponding planning and management measures should be implemented in different biodiversity hotspots according to the changes in geographic distribution. In this paper, we propose practical advice for different regions to improve isolated and fragmented habitats, which will support the conservation of Coleoptera taxa and the restoration of biodiversity