Search

Quartz fiber fabric is widely used in national defense, military and aerospace industries due to its good high-temperature resistance, chemical stability and excellent thermal shock resistance. However, the tendency of quartz fiber fabric to undergo thermal degradation due to crystallization at high temperature may destroy its high-temperature performance, particularly its high-temperature mechanical properties. In this study, an aluminum oxide (Al2O3) ceramic coating was synthesized on the surface of two-dimensional quartz fiber fabric in aqueous solution near room temperature. The surface morphology and chemical composition were studied to evaluate the quality of the coating by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The annealing behavior at high temperature was evaluated by using an electronic universal testing machine after high-temperature processing. The annealing behavior of the aluminum oxide coating could be improved effectively. The maximum load that the coated fabric can bear was 2.5 times higher than that of the original fabric, proving the superior high-temperature mechanical properties of the coated fabric. The coating on the surface of the fiber could block the damage of high temperature to the quartz fiber, improving the crystallization phenomenon of the quartz fiber at high temperature, followed by improvement in the high-temperature mechanical properties of the fabric.

This paper proposes a new air cycle system by replacing the turbine assembly with vortex tubes and a parameter-matching method independent of the architecture of the air cycle system. Only, in terms of refrigerating and dehumidification, the performance of the newly proposed vortex system is worse than that of a conventional air cycle system under the same bleed air parameters. However, for aircraft practical applications, the overall performance of air cycle systems requires additional considerations such as the heating capacity, weight of the system, and extra aviation fuel used to transport that weight. Therefore, this paper conducts an integrated performance comparison between the new system and a conventional system based on the overall fuel mass penalty criterion. The results show that whether the new system has a smaller total takeoff mass depends on the bleed air parameters, flight duration, and flight speed. For specific bleed air parameters, there is a specific [Formula: see text] curve where the new system and the turbine system have the same total takeoff mass. The performance of the new system is better than that of the turbine system only when the values of flight Mach number and flight duration are at the lower left of the [Formula: see text] curve.

Soil salinization is one of the most important issues threatening agricultural production, food security and sustainability in arid and semi-arid regions worldwide. The improvement and comprehensive utilization of saline alkali soil is of great significance for cultivating healthy soil, ensuring global food security and mitigating climate change. This paper summarized the research progress of saline alkali soil improvement technology, and described briefly the causes of saline-alkali land. Moreover, the physical, chemical and biological methods of saline-alkali land improvement were analyzed. The improvement characteristics and effects of different materials and technologies are described. And we proposed suggestions for future research and development of desalination materials and technologies to provide a useful reference for the research and development of efficient improvement technology of saline-alkali soil, and accelerate the improvement of saline-alkali land and improve the quality of cultivated land to a greater extent.

The farmland soil is combined pollution by multi-heavy metals in China, which seriously threatens the food security and the human health. This paper makes a review of the characteristics of the heavy metal contaminated farmland soil and the types and characteristics of common remedial materials. In addition, this paper analyzed and forecasted the problems that need to be solved in the future for remedial materials for heavy metal contaminated soil. Common remediation materials include biochar, clay minerals, organic matter, phosphates, metal oxides and composite remediation materials, etc. The remediation materials can effectively reduce the mobilization and bioavailability of heavy metals. This paper summarized the types and characteristics of remedial materials for heavy metal contaminated soil, so as to provide theoretical basis for remediation materials and prevention and control strategy for the heavy metal pollution.

Collective argumentation is the process of reaching a collective decision that is acceptable to the group in a debate. We introduce the notion of topological restriction to enrich the study of collective argumentation. Topological restrictions are rational constraints assumed to be satisfied by individual agents. We assume that in a debate, for every pair of arguments under consideration, every agent indicates whether the first argument attacks the second, i.e. an agent’s argumentative stance is characterized as an argumentation framework, and only argumentation frameworks that satisfy topological restrictions are allowed. The topological restrictions we consider in this paper include various topological properties in the literature, such as acyclicity, symmetry, coherence and determinedness, as well as three topological restrictions that generalize classic social-choice-theoretic domain conditions. We show that when the profile of the argumentation frameworks provided by the agents satisfies topological restrictions, impossibility results during aggregation can be avoided. Furthermore, if a profile is topologically restricted with respect to restrictions that generalize domain conditions, then the majority rule preserves several desirable properties during aggregation.

Aim: To discuss Den on apoptosis and Nrf2/ARE in atherosclerotic vulnerable plaque of apolipoprotein in E (ApoE)-/- mice. Methods: Randomly dividing ApoE-/- mice as 5 groups including Normal, Model, Den-L (10 mg/kg), Den-M (20 mg/kg) and Den-H (40 mg/kg) groups. The atherosclerotic vulnerable plaque model was established by high-fat feeding and right common carotid artery catheterization (perivascular carotid collar placement, PCR), and Den was given by difference concentration Den, the pathological changes of right common carotid arery, apoptosis of vascular smooth muscle, Bax, Bcl-2 and Caspase-3 proteins expression using IHC and WB assay, Nrf2, ARE and MDA, 8-OHdG and TAC levels were detected. Results: Model group showed typical pathological changes of vulnerable plaque, the apoptosis cell number, Bax, Caspase-3 and MDA, 8-OHdG significantly increased, the Bcl-2, Nrf2, ARE and TAC levels significantly decreased (P < 0.001, respectively); Compared with model group, the plaque of Den groups were reduced and tended to be stable, the apoptosis cell number, Bax, Caspase3 and MDA, 8-OHdG levels significantly decreased, Bcl-2, Nrf2, ARE and TAC levels significantly increased (PConclusion: Den improves atherosclerotic vulnerable plaque of ApoE-/- mice, which is related to the inhibition of apoptosis and Nrf2/ARE pathway.

Bi-doped germanate glasses are reported as all-inorganic tunable broadband NIR LED devices (gc-LEDs) operating in both NIR-I and NIR-II regions with potential applications in night vision, bio-imaging, and rapid analysis of food quality.

An aggregation and crosslinking strategy is proposed for constructing high-relaxivity C-BM. The further increased r1, stabler FL, stronger PA and better PT effect are achieved in C-BM/I, which can be used for MR, NIR-II FL and PA imaging and PTT-PDT.

The atmospheric oxidation of chemicals has produced many new unpredicted pollutants. A microwave plasma torch-based ion/molecular reactor (MPTIR) interfacing an online mass spectrometer has been developed for creating and monitoring rapid oxidation reactions. Oxygen in the air is activated by the plasma into highly reactive oxygen radicals, thereby achieving oxidation of thioethers, alcohols, and various environmental pollutants on a millisecond scale without the addition of external oxidants or catalysts (6 orders of magnitude faster than bulk). The direct and real-time oxidation products of polycyclic aromatic hydrocarbons and

Purpose: To explore the impact of VEGF pathway on the M1 polarization and function of macrophages. Methods: VEGFR-knockdown macrophages were established by transfected with a shRNA. M1 macrophages were stimulated by LPS and IFN-γ, which was identified using the flow cytometry. Subsequently, M1 macrophages were treated with VEGF A, VEGF B, and PIGF, respectively. The expression level of iNOS, TNF-α, and IL-6 was detected utilizing RT-PCR. CD86 and iNOS level were checked by Western blot. The migration of HUVEC was evaluated by wound healing assay. Results: The percentage of F4/80+CD86+ macrophages was significantly elevated by the transfection of shRNA, accompanied by a significantly upregulated expression of CD86 and iNOS. After the stimulation of LPS and IFN-γ, CD86 and iNOS was dramatically upregulated in both the Lv-NC group and Lv-shVEGFR1 group. IL-6 and iNOS levels were greatly declined in macrophages co-treated with LPS, IFN-γ, and PIGF. No marked alterations on the healing degree were noticed in HUVEC stimulated by the supernatant of LPS/IFN-γ treated macrophages, which was dramatically declined by the knockdown of VEGFR1. Conclusion: VEGFR1 facilitated the effect of macrophages on HUVEC migration by regulating the M1 polarization.

Agricultural resources and environment suffer from exogenous pollution and endogenous pollution, and the sustainable development of agriculture encounters a bottleneck. And we need to pay enough attention to agricultural non-point source pollution that is widely distributed and affects large geographic areas. Agricultural non-point source pollution leads to increasing soil and water pollution and agricultural products quality and safety risks. Previous researches have focused on the environmental impact of point source and industrial pollution. However, that is insufficient attention to the importance of agricultural non-point source pollution. It is necessary to explore the balance between food safety, food security and the prevention and control of agricultural non-point source pollution. This paper presents the sources, pathways, pollutants and prevention methods of agricultural non-point source pollution, which have guiding significance for the protection of the agricultural environment and the sustainable development of agriculture.

In this paper, we study a capacitated production-distribution problem where facility location, production, and distribution decisions are tightly coupled and simultaneously considered in the optimal decision making. Such an integrated production-distribution problem is complicated, and the current commercial mixed-integer linear programming (MILP) solvers cannot obtain favorable solutions for the medium- and large-sized problem instances. Therefore, we propose an unsupervised learning-driven matheuristic that uses easily obtainable solution values (e.g., solutions associated with the linear programming relaxation) to build clustering models and integrates the clustering information with a genetic algorithm to progressively improve feasible solutions. Then we verify the performance of the proposed matheuristic by comparing its computational results with those of the rolling horizon algorithm, a non-cluster-driven matheuristic, and a commercial MILP solver. The computational results show that, under the same computing resources, the proposed matheuristic can deliver better production-distribution decisions. Specifically, it reduces the total system costs by 15% for the tested instances when compared with the ones found by the commercial MILP solver. Additionally, we apply the proposed matheuristic to a related production-distribution problem in the literature and obtain 152 equivalent or new best-known solutions out of 200 benchmark test instances.

The efficiency of deep neural network (DNN) solutions on real hardware devices are mainly decided by the DNN architecture and the compiler-level scheduling strategy on the hardware. When we try to fully exploit the underlying hardware and obtain the optimal tradeoff between DNN accuracy and runtime performance, we discovered that the two optimization goals of DNN architecture and scheduling policy are intimately related to each other. However, current hardware-aware Neural Architecture Search (NAS) methods primarily focus on the DNN architecture search process, ignoring the effects of various compiler-level scheduling strategies (e.g., graph-level optimization, loop transformations, parallelization, etc.) on network candidates being evaluated in the search process. As a result, they may overlook the true-optimal DNN implementations on hardware, which can only be discovered by trying-out different combinations of scheduling strategies and DNN architectures. This work proposes a NAS framework (CHaNAS) that searches for not only the network architecture but also the dedicated compiler-level scheduling policy, as the optimal co-design solution on the target hardware. We propose to use a block-based pre-scheduling methodology to reduce the co-design search space and enable the automatic generation of the optimal co-design, including the network architecture and the tensor programs that practice the scheduling policy. Further, we introduce a new search objective function based on the generalization gap to prevent the selection of architectures that are prone to overfitting. We evaluate CHaNAS on Imagenet on different hardware back-ends against the state-of-the-art hardware-aware search method based on the MobileNet-v3 search space. Experimental results show that the co-design solutions obtained by ChaNAS show up to 1.6×, 1.9×, and 1.7×, 24 performance boost on NVIDIA P100 GPU, Intel Xeon 8163 CPU, and Samsung Note 10 Mobile, respectively, over the baselines of the same-level accuracy.

In mass spectrometry (MS), nonvolatile salts contaminate the transmission system and cause ion suppression, hampering MS analysis. When MS is combined with liquid chromatography (LC) that uses a salty mobile phase, the problems become more intractable due to long analysis time. Here, a novel heat-assisted dual neutral spray ionization (HADSI) method was developed, which projected sample solution spray and solvent spray onto a heated plate to achieve online desalting and high ionization. The experimental parameters of HADSI were optimized, which indicated that the plate temperature was crucial for ionization and desalination. Eight drug compounds dissolved in various commonly used buffers were directly analyzed using HADSI-MS, even though the concentration of PBS buffer reached 500 mmol/L. The established method showed considerable sensitivity in the positive ion mode with the limits of detection at the level of nmol/L, and good linearity (

Genome resequencing uncovers genome-wide DNA polymorphisms that are useful for the development of high-density InDel markers between two barley cultivars. Discovering genomic variations and developing genetic markers are crucial for genetics studies and molecular breeding in cereal crops. Although InDels (insertions and deletions) have become popular because of their abundance and ease of detection, discovery of genome-wide DNA polymorphisms and development of InDel markers in barley have lagged behind other cereal crops such as rice, maize and wheat. In this study, we re-sequenced two barley cultivars, Golden Promise (GP, a classic British spring barley variety) and Hua30 (a Chinese spring barley variety), and mapped clean reads to the reference Morex genome, and identified in total 13,933,145 single nucleotide polymorphisms (SNPs) and 1,240,456 InDels for GP with Morex, 11,297,100 SNPs and 781,687 InDels for Hua30 with Morex, and 13,742,399 SNPs and 1,191,597 InDels for GP with Hua30. We further characterized distinct types, chromosomal distribution patterns, genome location, functional effect, and other features of these DNA polymorphisms. Additionally, we revealed the functional relevance of these identified SNPs/InDels regarding different flowering times between Hua30 and GP within 17 flowering time genes. Furthermore, we developed a series of InDel markers and validated them experimentally in 43 barley core accessions, respectively. Finally, we rebuilt population structure and phylogenetic tree of these 43 barley core accessions. Collectively, all of these genetic resources will facilitate not only the basic research but also applied research in barley.

Tacrolimus (FK506) is widely used in the prevention of organ transplant rejection and the treatment of autoimmune diseases, but it is difficult to detect within the low and narrow concentration range in practical clinical fields. A magnetic plasmonic superstructure-targets-plasmonic superstructure-based sandwich-type SERS biosensor is presented here to ultrasensitively detect FK506 in the blood of organ transplant patients. The spiky Fe

It remains a challenge for platinum-based oxygen reduction reaction catalysts to simultaneously possess high mass activity and high durability in proton-exchange-membrane fuel cells. Herein, we report ultrathin holey nanotube (UHT)-structured Pt-M (M = Ni, Co) alloy catalysts that achieve unprecedented comprehensive performance. The nanotubes have ultrathin walls of 2-3 nm and construct self-supporting network-like catalyst layers with thicknesses of less than 1 μm, which have efficient mass transfer and 100% surface exposure, thus enabling high utilization of Pt atoms. Combined with the high intrinsic activity produced by the alloying effect, the catalysts achieve high mass activity. Moreover, the nanotube structure not only avoids the agglomeration problem of nanoparticles, but the low curvature of the tube wall also gives UHT a low surface energy (less than 1/3 of that of the same size nanoparticle), so UHT is more resistant to the Ostwald ripening and is stable. For the first time, the U.S. DOE mass activity target and dual durability targets for load and start-stop cycles are achieved on one catalyst. This study provides an effective structural strategy for the preparation of electrocatalysts with high atomic efficiency and excellent durability.

Zeolites were modified by high-temperature roasting and chitosan loading, respectively. As a result, activated zeolite and chitosan-loading natural zeolite were obtained. They were used for the treatment of the micro-polluted irrigation water quality simulated by a low concentration (100 μg/L) of Cd(II) contamination. The static adsorption experiments showed that two types of modified zeolites were cost-effective and had high removal efficiency for low concentrations of Cd(II). The removal rates were 95.8% and 92.06%, respectively. The static adsorption experiments investigated the effects of modified zeolite dosage, pH, initial concentration of the solution, and adsorption time on the removal efficiency of cadmium ions. The dynamic adsorption experiments discussed the influence of factors such as dynamic adsorption medium type, influent filtration rate, and adsorbent amount on adsorption efficiency in the adsorption column. The dynamic adsorption experiments adopted intermittent operation to simulate the characteristics of micro-polluted irrigation water. The optimal operating conditions were determined as follows: single activated zeolite filter column or mixed medium (activated zeolite: chitosan loading natural zeolite = 4:1), filtration rate of 6 m/h, filter column height of 500 mm, adsorbent dosage of 30 g. The removal rate was more than 99.5%. The adsorption experiments were represented by Langmuir and Freundlich isotherm models. The adsorption results indicated that the adsorption of modified zeolite showed a better correlation with the Langmuir isotherm model than the Freundlich isotherm model. The adsorption process was described by pseudo-first-order and pseudo-second-order kinetic models, with the pseudo-second-order kinetic model being the predominant mechanism. The average concentration of Cd(II) in the effluent after filtration was 0.41 μg/L, which was far lower than the 0.01 mg/L stipulated in the standard for irrigation water quality (GB5084-2021), and met the requirements of the irrigation water quality standard. Activated zeolite and chitosan-loaded natural zeolite are good adsorbent materials that have broad application prospects in the treatment of micro-polluted irrigation water containing low concentrations of Cd(II).

Multipath error is an important factor restricting the relative positioning accuracy of the Beidou Navigation Satellite System (BDS). Because of the complexity of the reflection environment, the mathematical modeling of multipath errors is quite difficult. The sidereal filtering algorithm corrects multipath errors by using the feature of period repetition, which can greatly reduce its influence and improve the accuracy of positioning and attitude measurement. In view of the constellation heterogeneity of BDS, it is more complicated to apply sideral filtering. Based on the reconstructed single-difference residual of the carrier phase, the multipath repetition time of the Beidou satellite is estimated using the idea of segmentation. The Tikhonov regularization method and the classical wavelet method are used to extract the multipath of the single-difference residual of the carrier phase, and the “clean” sequence of the single-difference residual is obtained. The experimental results show that it is feasible to extract the multipath error correctly by Tikhonov regularization, and the multipath error is smoother than the original residual measurement. Furthermore, the estimation method of the regularization parameter is further optimized. After using the optimized Tikhonov regularization method with sidereal filtering, the mean RMS improvements of GEO, IGSO, and MEO satellites are 45.9%, 38.2%, and 37.5%, respectively. The positioning accuracy on E, N, and U components is improved by 24.8%, 26.3%, and 42.7%, respectively. The attitude resolution accuracy is improved by 22.9% in the yaw angle and 12.6% in the pitch angle. The proposed method can be an alternative BDS multipath error modeling and mitigation approach.

With the continuous development of social economy, water pollution has become one of the key objects of ecological environment governance. It is one of the effective methods to remove heavy metals, nitrogen, phosphorus, antibiotics and other organic pollutants from water by using carbon-based poly porous materials. The physical and chemical properties of porous materials can be improved effectively and the removal effect of target pollutants can be enhanced. The removal of heavy metals, nitrogen, phosphorus and organic matter from water by modified porous materials and its possible mechanism were reviewed. The future research and application of modified porous materials in the field of water pollution control were prospected, which could provide useful reference for related research work and engineering application.

This paper takes the village in the city as a case study, through the investigation of the basic information of the village in the city, such as housing construction, construction quality, property rights characteristics, and so on. We use GIS technology to evaluate the construction and reconstruction cost of the plot. This paper puts forward different transformation schemes and explores the application of GIS technology in the transformation planning of urban villages. Finally, this paper designs a GIS-based spatial experience system for micro-transformation of urban villages.

Emergency department (ED) visits for drug overdoses increased nationally during COVID-19 despite declines in all-cause ED visits. The study purpose was to compare characteristics of ED visits for opioid and stimulant overdoses before and during COVID-19 in Florida. This study tested for disparities in ED visits for opioid and stimulant overdoses by race/ethnicity, age, and insurance status. The study identified ED visits for opioid and stimulant overdose in Florida during quarters two and three of 2019 and compared them with quarters two and three of 2020. Overall, there was an increase in the number of opioid and stimulant overdoses during COVID-19. Combined with the decline in the number of all-cause ED visits, drug overdoses represented a larger share of ED visits during COVID-19 compared with before COVID-19. The study did not find evidence of disparities by race/ethnicity, as each group experienced similar increases in the likelihood of ED visits involving drug overdoses during COVID-19. Differences emerged according to age and insurance status. ED visits involving those under age 18 were more likely to involve opioid or stimulant overdose, and ED visits among those over age 65 were less likely to involve opioid overdose during COVID-19. ED visits among those with vulnerable insurance status were more likely to involve opioid overdose during COVID-19. Patterns of behavior change during periods of restricted activity due to a pandemic. These changes in behavior change the mix of risks that people face, suggesting the need for a reallocation of population health management resources during pandemics.

ObjectiveWe aimed to investigate the effect of Cyclocarya paliurus leaves extracts (CP) on glucose and blood lipid metabolism and its relationship with intestinal flora in type 2 diabetes mellitus (T2DM) patients.MethodsIn this open-label, 84-day randomized controlled trial, a total of 38 T2DM patients were randomly assigned to the CP group or the Glipizide group (G group) in a 2:1 ratio. T2DM-associated metabolic phenotypes, gut microbiota and metabolites including short-chain fatty acids (SCFAs) and bile acids (BAs) were detected.ResultsAt the end of intervention, CP, like Glipizide, significantly improved HbA1c level and other glucose metabolism parameters (fasting plasma glucose (FBG), 2-hour post-meal blood glucose (2hPBG), the area under curve of oral glucose tolerance test glucose (OGTT glucose AUC)). Moreover, CP also resulted in the significant improvement in the levels of blood lipid and blood pressure. Notably, the improvement in blood lipid(triglycerides (TG) and high-density lipoprotein cholesterol (HDL-c)) and blood pressure (diastolic blood pressure (DBP)) was significantly greater in the CP group compared with the G group. Furthermore, the liver and kidney function parameters did not significantly change in both CP group and the G group over the 84-day period. Additionally, the enrichment of potentially beneficial bacteria (Faecalibacterium and Akkermansia), SCFAs and unconjugated BAs and the depletion of potential pathogenic bacteria (Prevotella_9) and conjugated BAs were observed in the CP group, while the abundances of the gut microbial were kept stable in the G group after intervention.ConclusionCP displays a more beneficial effect in the alleviation of T2DM-associated metabolic phenotypes than glipizide by regulating gut microbiota and metabolites in T2DM patients, with no significant effects on liver and kidney function.