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Purpose: Accurate estimation of soil organic matter (SOM) content is crucial for agricultural production. The integral-order differential hyperspectral processing might easily lead to the loss of trace hyperspectral information of substances, especially in moist condition. The aim of this study was to propose a method which can enhance the characteristics of SOM and improve the prediction accuracy of SOM in moist condition. Materials and methods: This study firstly used the fractional-order differential (FOD) technique to refine the hyperspectral information, performing 0 ~ 2 order differential preprocessing on the hyperspectral spectrum with a step of 0.1, and then, the significance level at 0.05 was taken to complete the screening. Afterwards, traditional machine learning algorithms (partial least squares regression) and ensemble learning algorithms (eXtreme gradient boosting (XGBoost), light gradient boosting machine (LightGBM), and random forest (RF)) were applied to predict SOM content. Based on 21 different differential orders and 4 learning algorithms, a total of 84 models were established. Coefficient of determination (R2), root mean square error (RMSE), residual prediction deviation (RPD), and Lin's consistency correlation coefficient (LCCC) were used to evaluate the prediction accuracy. Standard deviation was applied to represent the uncertainty of the models. Results and discussion: The results showed that FOD processing of hyperspectra could effectively mine highly efficacious information and improve prediction accuracy of SOM. The best model was believed to be the XGBoost algorithm with 0.8-order differential, and its values of R t 2 , RMSE t , RPD t , and LCCC t were 0.81 ± 0.02, 6.95 ± 0.31 g kg−1, 2.24 ± 0.02, and 0.90 ± 0.01, respectively. Conclusions: Briefly, FOD showed tremendous potential in enhancing spectral characteristics of SOM; its combination with ensemble learning can improve the prediction accuracy of SOM. Furthermore, it also provides a new approach to rapidly and accurately acquire other soil attributes. [ABSTRACT FROM AUTHOR]

SrZrS3 is a promising chalcogenide perovskite with unique advantages including high abundance of consisting elements, high chemical stability, strong light absorption above its direct band gap, and excellent carrier transport ability. While unfortunately, due to the lack of breakthroughs in its thin film synthesis technique, its optoelectronic properties are not fully investigated, not to mention the device applications. In this work, large-area and uniform SrZrS3 thin film (5 cm × 5 cm) was prepared by facile sputtering method, followed by a post-annealing treatment at a high temperature of 1000 °C for 2–12 h under CS2 atmosphere. All SrZrS3 samples prepared adopt distorted orthorhombic structure with pnma space group and have high crystallinity. In addition, the band gap of SrZrS3 thin film is measured to be 2.29 eV, higher than that of the powder form (2.06 eV). Importantly, the light absorption coefficient of SrZrS3 thin film reaches over 105 cm−1, and the carrier mobility is as high as 106 cm2/Vs. The above advantages allow us to use the SrZrS3 thin film as photoactive layer for photodetector applications. Finally, a symmetrically structured photoconductive detector was fabricated, performing a high responsivity of 8 A/W (405 nm light excitation). These inspiring results promise the glorious application potential of SrZrS3 thin film in photodetectors, solar cells, and other optoelectronic devices. [ABSTRACT FROM AUTHOR]

We have synthesized the quaternary copper selenide BixCu2−3xSe0.95Te0.05 compounds by high-pressure followed with ball milling method and investigated their thermoelectric properties. The crystal structure and element doping are characterized and verified by the X-ray diffraction, high-resolution transmission electron microscope and X-ray photoelectron spectroscopy. Compared with other samples, the samples with x = 0.001 and 0.002 have larger layered grain size and smaller grain boundary. This may lead to the reduction of resistivity in a wide temperature range, thus realizing the optimization of electronic characteristics. The dislocation-induced lattice strain fluctuations may cause the abrupt thermal conductivity, which is contrary to the previous results. Eventually, a peak value of zT = 1.03 at 873 K is obtained for Bi0.001Cu1.997Se0.95Te0.05 and Bi0.002Cu1.994Se0.95Te0.05. [ABSTRACT FROM AUTHOR]

Purpose: Antihypertensive medication is an effective way to control blood pressure. However, some studies reported that it may affect patients' sleep quality during the treatment. Due to the inconsistency of present results, a comprehensive systematic review and network meta-analysis are needed. Methods: Electronic databases (MEDLINE, EMBASE, WEB OF SCIENCE, PUBMED) were searched up to April 10th, 2021 including no restriction of publication status. Randomized controlled trials (RCTs) or quasi-experimental studies or cohort studies were eligible. The network meta-analysis was used within a Bayesian framework. Results: Finally, 16 publications (including 12 RCTs and 4 quasi-experimental studies) with 404 subjects were included in this study. Compared to placebo, the results of the network meta-analysis showed that diuretics were effective in improving sleep apnea with a mean difference (MD) of − 15.47 (95% confidence interval [CI]: − 23.56, − 6.59) which was consistent with the direct comparison result (MD: − 17.91; 95% CI − 21.60, − 14.23). In addition, diuretics were effective in increasing nocturnal oxygen saturation with an MD of 3.64 (95% CI 0.07, 7.46). However, the effects of β-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, and the others on sleep apnea were not statistically significant. Additionally, the effects of antihypertensive medication on the total sleep time (min), rapid eye movement (%), and sleep efficiency (%) were not statistically significant. Conclusion: Our study found that diuretics could effectively reduce the severity of sleep apnea in hypertensive patients. However, the effects of antihypertensive drugs on sleep characteristics were not found. [ABSTRACT FROM AUTHOR]

Piezochromic luminescent materials have shown great potential in advanced optoelectronic applications. However, most of luminescent materials usually undergo emission quenching under external stimuli. Herein, we demonstrate for the first time that the photoluminescence of carbon dots (CDs) confined within sodium hydroxide can be enhanced when high pressure is applied. They exhibit a 1.6-fold fluorescence enhancement compared with pristine CDs. Importantly, the enhanced fluorescence intensity can be retained after the release of pressure to ambient conditions. A combination of experimental analysis and theoretical simulations indicates that such an enhanced emission is mainly attributed to the strong confinement resulting from the sodium hydroxide matrix, which can separate the CDs spatially and restrict the nonradiative pathway. These results provide a rational strategy for manipulating the optical properties of CDs with enhanced and retainable photoluminescence (PL) performance, thus opening up a venue for designing luminescent CDs-based materials. [ABSTRACT FROM AUTHOR]

Based on the biopsychosocial model of Internet addiction, this study tested a moderated mediation model of familial (i.e., perceived autonomy-supportive parenting), psychological (i.e., need satisfaction) and biological (i.e., baseline respiratory sinus arrhythmia, RSA) factors to investigate how they jointly impact Internet addiction in emerging adults; specifically, we explored whether RSA moderated the mediating effect of need satisfaction on the relation between perceived autonomy-supportive parenting and Internet addiction. A total of 146 Chinese undergraduates completed questionnaires on autonomy-supportive parenting, need satisfaction and Internet addiction. RSA data were also obtained. Path analysis was used to test the proposed mediation and moderated mediation models. The results indicated that while the impact of perceived autonomy-supportive parenting on Internet addiction was mediated by need satisfaction, RSA moderated this indirect effect. The indirect effect of autonomy-supportive parenting on Internet addiction via need satisfaction was much stronger in adults with low levels of RSA than in those with high levels of RSA. Our findings highlight the joint impact of biological, psychological, and social-environmental factors on Internet addiction and have important implications for the prevention of and intervention against emerging adults' Internet addiction. [ABSTRACT FROM AUTHOR]

Motivated by prototypes that the heavy-element doping can effectively tune carrier and phonon transport behavior, we studied the influence of Bi doping on the thermoelectric properties of Cu2Se synthesized by high-pressure and high-temperature technique. With the increased Bi contents, the carrier mobility of BixCu2Se samples distinctly decreased, while the Seebeck coefficient and electrical resistivity increased. The BixCu2Se samples exhibited multiple microstructures including abundant grain boundaries, micropores and lattice defects. Various phonon scattering mechanisms generated relatively low lattice thermal conductivity below 0.55 Wm−1 K−1 for all Cu2Se-based samples. The lattice thermal conductivity of Cu2Se-based samples increased after Bi doping due to reduced degree of disorder of Cu+ ions, which weakened phonon scattering. Due to the significantly reduced thermal conductivity, a peak zT value of 1.57 at 873 K was obtained for Bi0.005Cu2Se sample, which was 25% higher than that of pristine Cu2Se (zT ~ 1.25). This work indicates the potential of heavy-element doping in boosting performance for liquid-like thermoelectrics. [ABSTRACT FROM AUTHOR]

Pectinase is widely used in numerous industrial fields, including the food, wine, and paper industries. In this work, seven bacteria were isolated from orange peel and their pectinase production activity was assayed. One bacterium (OR-B2) identified as a Bacillus sp. showed the highest enzyme activity towards others. A gene encoding a pectate lyase designed as PelB-B2 in this work was amplified and heterogeneous expressed in E.coli. PelB-B2 was defined as a member of the PelB pectate lyase family after phylogenic tree analysis. 3D model of PelB-B2 was constructed by SWISS-MODEL and PelB-B2 showed conserved para-β structure. After inducing culture and purified by Ni-affinity chromatography, the properties of the purified PelB-B2 were assayed. Optimal pH and temperature for PelB-B2 was pH 8.0 and 50 °C, respectively. PelB-B2 showed excellent pH stability and thermostability. It was stable within pH range 3.0–11.0 and retained more than 51% activity after incubation at 40 °C, 50 °C, or 60 °C for 1 h. Furthermore, we determined that PelB-B2 was a Ca2+-dependent pectinase and the pectin extracted from citrus was the benefit substrate for PelB-B2. The Km and Vmax of PelB-B2 were 1.64 g/L and 232.56 mol/(L min), respectively. The OR-B2 can be a new resource for pectinase production and the PelB-B2 has potential for industrial application. 7 bacteria were isolated from orange peel, namely OR-B1 to OR-B7 and their pectinase activities were assayed. One pectate lyase belongs to PelB family was cloned from OR-B2 and heterogeneous expressed in E. coli. Purified PelB-B2 was further studied with its properties. Effects of pH, temperature, chemicals, substrate on the enzyme activity were assayed and the enzyme kinetic was also measured. [ABSTRACT FROM AUTHOR]

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Cu2Se has been considered as a promising thermoelectric material due to its unique structure and excellent performance. Herein, a series of Cu2-xNaxSe (x = 0, 0.01, 0.02, 0.03, and 0.04) polycrystalline samples were synthesized by combining hydrothermal synthesis and hot pressing to investigate the effects of Na-doping on the microstructure and thermoelectric properties of Cu2Se. Compared with the pristine Cu2Se, the Na-doping introduces numerous micro-pores that can optimize the thermal transport performance by strong phonon scattering effects of interfaces between the micro-pores and grains. The doped samples have excellent electrical properties and low thermal conductivity. The maximum value of ZT = 2.1 is obtained at 973 K for the Cu1.96Na0.04Se sample with nominal composition. The results confirm that introducing Na into Cu2Se is an effective and convenient strategy to improve the thermoelectric performance of the Cu2Se alloy by decreasing the lattice thermal conductivity. [ABSTRACT FROM AUTHOR]

Non-stoichiometric Cu2−xSe is considered as a potential “phonon liquid electronic crystal” thermoelectric material. Cu1.98Se has higher thermal conductivity than Cu2Se, but the power factor of Cu1.98Se is about twice that of Cu2Se. Its thermal conductivity could be further depressed by optimizing its thermal transport performance. In this work, lead-doped Cu1.98−xPbx/2Se (x = 0-0.03) nanopowders were synthesized using a hydrothermal method, and hot-pressed into bulk pellets to assess the effects of Pb doping on the thermoelectric properties of Cu1.98Se. The electrical resistivity and the Seebeck coefficients were increased by Pb doping. Ionization impurity scattering, together with decrease of hole concentration, appeared to decrease the electrical transport performance. The point defects and reduced carrier concentration together result in low thermal conductivity and lead to a high dimensionless figure of merit (ZT) value of 1.52 at 973 K for the nominal component Cu1.95Pb0.015Se sample. [ABSTRACT FROM AUTHOR]