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Surface enhanced Raman scattering (SERS) is a rapid and nondestructive technique that is capable of detecting and identifying chemical or biological compounds. Sensitive SERS quantification is vital for practical applications, particularly for portable detection of biomolecules such as amino acids and nucleotides. However, few approaches can achieve sensitive and quantitative Raman detection of these most fundamental components in biology. Herein, a noble-metal-free single-atom site on a chip strategy was applied to modify single tungsten atom oxide on a lead halide perovskite, which provides sensitive SERS quantification for various analytes, including rhodamine, tyrosine and cytosine. The single-atom site on a chip can enable quantitative linear SERS responses of rhodamine (10Supplementary material is available for this article at 10.1007/s40843-022-1968-5 and is accessible for authorized users.表面增强拉曼散射(SERS)是一种快速且无损的化学和生物分子检测技术. 高灵敏且定量化的SERS检测技术对其在实际中的应用至关重要, 尤其是对生物分子如氨基酸和碱基的便携化检测. 但是鲜有技术手段能够实现对这些最基本的生物分子进行高灵敏且定量化的拉曼检测. 我们提出了一种无需贵金属的单原子位点修饰芯片策略, 用钨单原子氧化物修饰铅卤钙钛矿芯片, 实现了多种检测物的高灵敏定量化识别, 包括罗丹明、 酪氨酸和胞嘧啶. 芯片上单原子位点技术能够实现对罗丹明、 酪氨酸和胞嘧啶的线性检测, 相应的定量化区间分别为: 10

A high-resolution nutrient emission inventory can provide reliable and accurate identification of priority control areas, which is crucial for efficient decisions on water quality restoration. However, the inventories widely used in large-scale modeling are usually based on provincial inputs, which induce the challenges of lacking localized parameters and missing localized characteristic when provincial scale inputs are converted to finer scales with the down-scale methods. Based on elaborate investigations and statistical data at the county scale with multi-scale data conversion, the China Emission Inventory of Nutrients (CEIN) was developed with a spatial resolution of a 0.1° grid and sub-basin scales. The Yangtze River Basin was used as a case study to illustrate the potential applications of CEIN. The emissions of total nitrogen (TN) and total phosphorus (TP) of Yangtze River Basin is 0.43 Mt and 0.04 Mt for point sources, 11.09 Mt and 4.64 Mt for diffuse sources in 2017. The hotspot analysis for 2606 sub-basins indicated that cropland is the key source of nutrient emissions, accounting for 58.88% and 79.15% of TN and TP, respectively. Industrial sewage and freshwater aquaculture accounted for 27.39% (TN) and 21.98% (TP) of the point sources, which is substantial due to their direct discharge into surface waters. The current results also reveal that, in contrast to CEIN, the previously used common emission factors based on GDP per capita produced considerable overestimations of 2.37 and 2.65 times the actual TN and TP emissions, respectively. Additional advantages of the CEIN have been demonstrated in identifying priority control areas more accurately with reduced bias and quantifying the effects of policies at much smaller scales. For example, the CEIN helps to distinguish hotspots, which was neglected when identifying sources at the level-III sub-basin scale, and indicates that the management of fractional areas (TN: 16.97%; TP: 13.44%) provides the highest nutrient emissions control (TN: 44.34%; TP: 48.65%) for the entire basin. The evaluation of China's toilet revolution policy demonstrates that achieving equitable access to safe sanitation has resulted in a reduction of 7240 t of TN and 833 t of TP, which is extremely critical for rural water quality and health.

The operating life of the proton exchange membrane fuel cell stack is mainly decided by performances of its weakest single cell because of the “Buckets effect”, thus high voltage uniformity during a dynamic loading process is key to the stack durability. In this work, a 3-kW stack is examined experimentally on its voltage uniformity (voltage coefficient variation (Cv)) under conditions of loading from open-circuit state (0 A) to nominal current (165 A) and stack temperatures of 30 °C, 45 °C and 65 °C. Different dynamic loading strategies, namely constant loading rate strategy, decreasing loading rate strategy, and increasing loading rate (square/cube increasing loading rate) strategy, are examined and compared. Results display that during the loading process, (a) the voltage uniformity rises abruptly and goes down quickly when the loading current is small (e.g. from 0 A to 22 A), (b) the voltage uniformity under a small loading current is better than that under the open-circuit state, and (c) voltage uniformity decreases as the loading current increases from a small value to the nominal current. Comparisons of different current loading strategies show that as the stack temperature rises from 30 °C to 65 °C, the stack Cv value under the open-circuit state increases from 1.12 to 1.84 and decreases from 3.85 to 2.45 in the nominal current state. The maximum Cv for the decreasing loading rate strategy decreases from 16.25 to 9.49 and that of the constant loading rate strategy also decreases from 5.85 to 4.96. Cv values of the square current increasing loading rate strategy keep below 3.85 under conditions of the three stack temperatures and display a slight fluctuation during the whole current loading process, which indicates that the strategy can effectively make the stack being of an excellent voltage uniformity during the instantaneous response process.

Lead (Pb) is a type of toxic metal that can hurt the immune system. Selenium (Se) can reduce the damage caused by heavy metals. To investigate the effects of Se against Pb on bird immune cells, as well as the immunotoxin mechanism of Pb, Se supplementation and/or Pb poisoning chicken models were established. One hundred eighty 1-year-old broiler chickens were randomly divided into four groups (n = 6). The four groups were the control group, the selenium-rich group (Se group), the Pb supplementation group (Pb group) and the Se and Pb compound group (Se + Pb group). The peripheral blood lymphocytes of chickens were collected to test the selenoproteins and cytokine mRNA levels at 30 and 60 d. Determination of the content of Se and Pb in the serum, principal component analysis and ingenuity pathway analysis were performed at the two time points. As a result, Pb exposure increased the content of Pb, activating the Th1/Th2 pathway in peripheral blood lymphocytes. Additionally, this experiment showed that Se supplementation and Pb exposure could influence the mRNA levels of selenoproteins and cytokines in the peripheral blood lymphocytes of chickens. However, all of the parameters that we detected in the experiment indicated that Se supplementation could alleviate the increase of selenoproteins and cytokine mRNA levels and the Th1/Th2 imbalance induced by Pb in peripheral blood lymphocytes. In summary, Se can alleviate the toxic effects caused by Pb in the peripheral blood lymphocytes of chickens, suggesting the antagonism between Se and Pb.

This paper completed a program with a typical coal loading station analysis, coal systems, interior design by coal storage system loading stations will be expanded, it will be subject to the coal pit, different forms of storage bunker, coal storage shed, etc. specific technical parameters superior and its corresponding economic indicators combined standard to do a detailed comparison and determine the best technical and economic solutions Cargo station construction; focus on the application of matlab calculation program calculates the design reserves loading stations with coal shed aspect ratio, the relationship between the length of the curve values, verify the Cargo station design is reasonable to give a general rule of coal storage capacity design.

This article takes the coal washing wastewater of the Yidong Coal Preparation Plant as the research object. With the change of the raw materials to be washed, the effect of its existing treatment process is not ideal. The multi-factor response surface analysis of the four factors of PAC dosage, PAM dosage, stirring speed and stirring time was carried out, and the optimal dosage and operating parameters were obtained as PAC dosage 30.52 mg/L, PAM dosage The dose is 20.75 mg/L, the stirring speed is 407 r/min, and the stirring time is 82.5 s. Through the field industrial test, the application effect and rationality of the pressureless filtration technology are verified.

Segregation is a phenomenon of inhomogeneous distribution of constituent elements during crystallization and could be found in alloy, polymers, colloid, etc. Some researchers have also found component segregation in perovskite crystals. Until now, the existing research reports are all about the halogen segregation of perovskite at the micro level, while the research about the component segregation of perovskite at the macro level is blank, leaving no relevant application developed. Therefore, we can broaden the PUFs-based application of perovskite crystals by employing the multi-wavelength emission property arising from component macrosegregation. We synthesized perovskite crystal arrays with macroscopic composition segregation in one step by surface-tension-confined evaporative self-assembly. The macrosegregation in perovskite crystals prepared with different halogen ratios and temperature was surveyed. The photoluminescence spectra of perovskite crystals were investigated. Perovskite crystals with composition segregation could generate physically unclonable cryptographic primitives, which were made by a simple and random process and difficult to replicate. According to the number of peaks in the spectrum, we converted the optical response into quaternary cryptographic keys, and demonstrated the randomness and stability of the system. This study excavated the application prospect of macroscopic component segregation perovskite in all-photonic cryptographic primitives.

In order to research the vibration characteristics of the bearing plate on roadheader test bed to bear the roadheaders with different parameters, this paper establishes a multi-body dynamic model for the bear- ing plate to bear the roadheaders by using the theory of multi-body dynamics, and analyzes and determines a mathematical model of loads between the track and the bearing plate. By modal analysis of multi-body dynamic model of the roadheader, this paper extracts the modal shape of the system, and draws a frequency response dia- gram for system vibration, and obtains a larger vibration frequency range. To further explore the vibration char- acteristics, this paper researches the damping of different hydraulic systems, different mass, stiffness parameters and the impact of the roadheader on the vibration of the bearing plate on the test bed by using the computer nu- merical simulation, and obtains the longitudinal vibration characteristics of three test points in the geometric center, namely, cutting head, cantilever and engine body. The research results show that the mass of the road- header on the test bed is increased by 6%, and the longitudinal amplitudes of the cutting head and cantilever are respectively reduced by 37% and 19%; the damping of the hydraulic system of the roadheader is increased by 19%, and the longitudinal amplitudes of the cutting head, cantilever and engine body are respectively reduced by 33%, 23% and 16%; the stiffness of the engine body doubles, and the longitudinal amplitudes of the cutting head and cantilever are respectively reduced by 35.8% and 27%. The results are consistent with the underground in- dustrial test so as to provide a regularity basis for load analysis of the test bed bearing the roadheaders with dif- ferent parameters.

The 15-kDa selenoprotein (Sep15) is a thioredoxin-like protein. The expression of Sep15 is regulated by dietary selenium (Se) and plays important roles in mammals. However, the structure and function of chicken Sep15 and its response to Se are still unclear. In the present study, we replicated the chicken Se deficiency models and Sep15 deficiency models in splenocytes. Then, the homology, structure analysis, and levels of Sep15 were analyzed. In addition, the oxidative stress levels were examined in Sep15 deficiency splenocytes. The results indicated that chicken Sep15 preserved high similarity with that of other 14 animals in the coding nucleotide sequences (CDS) and deduced amino acid sequence, which suggested that chicken Sep15 may be derived from the same ancestor with other animals. The predicted structure and function showed that chicken Sep15 preserved the conserved thioredoxin-like fold CxU, which suggested an antioxidative function. Chicken Sep15 was also decreased by Se deficiency in immune organs (P