Two-dimensional C_(2)N-based single-atom catalyst with complex microenvironment for enhanced electrochemical nitrogen reduction:A descriptor-based design

The catalytic descriptor with operational feasibility is highly desired towards rational design of high-performance catalyst especially the electrode/electrolyte solution interface working under mild conditions.Herein,we demonstrate that the descriptorΩparameterized by readily accessible intrinsic properties of metal center and coordination is highly operational and efficient in rational design of single-atom catalyst(SAC)for driving electrochemical nitrogen reduction(NRR).Using twodimensional metal(M)-B_(x)P_(y)S_(z)N_m@C_(2)N as prototype SAC models,we reveal that^(*)N_(2)+(H~++e~-)→^(*)N_(2)H acts predominantly as the potential-limiting step(PLS)of NRR on M-B_(2)P_(2)S_(2)@C_(2)N and M-B_(1)P_(1)S_(1)N_(3)@C_(2)N regardless of the distinction in coordination microenvironment.Among the 28 screened M active sites,withΩvalues close to the optimal 4,M-B_(2)P_(2)S_(2)@C_(2)N(M=V(Ω=3.53),Mo(Ω=5.12),and W(Ω=3.92))and M-B_(1)P_(1)S_(1)N_(3)@C_(2)N(M=V(Ω=3.00),Mo(Ω=4.34),and W(Ω=3.32))yield the lowered limiting potential(U_(L))as-0.45,-0.54.-0.36,-0.58,-0.25,and-0.24 V,respectively,thus making them the promising NRR catalysts.More importantly,these SACs are located around the top of volcano-shape plot of U_(L) versusΩ,re-validatingΩas an effective descriptor for accurately predicting the high-activity NRR SACs even with complex coordination.Our study unravels the relationship between active-site structure and NRR performance via the descriptorΩ,which can be applied to other important sustainable electrocatalytic reactions involving activation of small molecules viaσ-donation andπ^(*)-backdonation mechanism.

Impact of Different Rates of Nitrogen Supplementation on Soil PhysicochemicalProperties and Microbial Diversity in Goji Berry

Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyze the functions of differential nitrogen application rates including low(N1),medium(N2),and high(N3)levels in soil microbial community structure(bacterial and fungal)at 2 diverse soil depths(0-20,20-40 cm)through high-throughput sequencing technology by targeting 16S RNA gene and ITS1&ITS2 regions.All the observed physicochemical parameters exhibited significant improvement(p<0.05)with increased levels of nitrogen and the highest values for most parameters were observed at N2.However,pH decreased(p<0.05)gradually.The alpha and beta diversity analyses for bacterial and fungal communities’metagenome displayed more similarities than differences among all groups.The top bacterial and fungal phyla and genera suggested no obvious(p>0.05)differences among three group treatments(N1,N2,and N3).Furthermore,the functional enrichment analysis demonstrated significant(p<0.05)enrichment of quorum sensing,cysteine and methionine metabolism,and transcriptional machinery for bacterial communities,while various saprotrophic functional roles for fungal communities.Conclusively,moderately reducing the use of N-supplemented fertilizers is conducive to increasing soil nitrogen utilization rate,which can contribute to sustainable agriculture practices through improved soil quality,and microbial community structure and functions.

Genetic Variation in Salt Stress Response and Germplasm Resource Evaluation among <i>Lycium</i>Accessions

Genetic variation between naturally occurring ecotypes can be helpful to elucidate the mechanism controlling salt stress response in different environments. The salt stress response of 20 natural accessions or cultivars of Lycium was characterized at a physiological level, following exposed to 300 mM NaCl for 15 days. It is shown that salt stress increased Na+, betaine and malondialdehyde (MDA) content, as well as the relative permeability of plasma membranes, but decreased K+, chlorophyll and glutathione (GSH) content, as well as K+/Na+ ratio compared with their respective control value in most of the varieties, though the increasing or decreasing extent has a clear genetic diversity. The physiological response was utilized to evaluate the salt-tolerant capacity of these varieties by principal component analysis and clustering analysis, and in which total chlorophyll, K+/Na+ ratio and partially GSH have the maximum weight relatively. These varieties could be categorized into four sub-groups, means greatly resistance (Heiguo, Ninqi No. 2 and Beifang), moderately resistant, sensitive, and mostly sensitive (Ninqi No. 7) to salt stress. Our results provide a theoretical basis and practical guidance for the improvement of saline-alkali land and rational utilization of Lycium germplasm resources in the future.

Colorectal cancer screening behavior and willingness:An outpatient survey in China

AIM： To identity the factors influencing colorectal cancer （CRC） screening behavior and willingness among Chinese outpatients.METHODS： An outpatient-based face-to-face survey was conducted from August 18 to September 7, 2010 in Changhai Hospital. A total of 1200 consecutive patients aged ≥ 18 years were recruited for interview. The patient＇s knowledge about CRC and screening was pre-measured as a predictor variable, and other pre- dictors included age, gender, educational level, month- ly household income and health insurance status. The relationship between these predictors and screening behavior, screening willingness and screening approach were examined using Pearson＇s 2 test and logistic regression analyses.RESULTS： Of these outpatients, 22.5% had undergone CRC screening prior to this study. Patients who had participated in the screening were more likely to have good knowledge about CRC and screening （OR： 5.299, 95% CI： 3.415-8.223）, have health insurance （OR： 1.996, 95% CI： 1.426-2.794） and older in age. Higher income, however, was found to be a barrier to the screening （OR： 0.633, 95% CI： 0.467-0.858）. An analysis of screening willingness showed that 37.5% of the patients would voluntarily participated in a screen at the recommended age, but 41.3% would do so under doctor＇s advice. Screening willingness was positively correlated with the patient＇s knowledge sta- tus. Patients with higher knowledge levels would like to participate in the screening （OR： 4.352, 95% CI： 3.008-6.298）, and they would select colonoscopy as a screening approach （OR： 3.513, 95% CI： 2.290-5.389）. However, higher income level was, again, a bar- rier to colonoscopic screening （OR： 0.667, 95% CI： 0.505-0.908）. CONCLUSION： Patient＇s level of knowledge and in-ome should be taken into consideration when conducting a feasible CRC screening.

QPSO-based algorithm of CSO joint infrared super-resolution and trajectory estimation

The midcourse ballistic closely spaced objects（CSO） create blur pixel-cluster on the space-based infrared focal plane,making the super-resolution of CSO quite necessary.A novel algorithm of CSO joint super-resolution and trajectory estimation is presented.The algorithm combines the focal plane CSO dynamics and radiation models,proposes a novel least square objective function from the space and time information,where CSO radiant intensity is excluded and initial dynamics（position and velocity） are chosen as the model parameters.Subsequently,the quantum-behaved particle swarm optimization（QPSO） is adopted to optimize the objective function to estimate model parameters,and then CSO focal plane trajectories and radiant intensities are computed.Meanwhile,the estimated CSO focal plane trajectories from multiple space-based infrared focal planes are associated and filtered to estimate the CSO stereo ballistic trajectories.Finally,the performance（CSO estimation precision of the focal plane coordinates,radiant intensities,and stereo ballistic trajectories,together with the computation load） of the algorithm is tested,and the results show that the algorithm is effective and feasible.

Glycosyltransferases and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease(NAFLD) is the most common form of chronic liver disease and its incidence is increasing worldwide. However, the underlying mechanisms leading to the development of NAFLD are still not fully understood. Glycosyltransferases(GTs) are a diverse class of enzymes involved in catalyzing the transfer of one or multiple sugar residues to a wide range of acceptor molecules. GTs mediate a wide range of functions from structure and storage to signaling, and play a key role in many fundamental biological processes. Therefore, it is anticipated that GTs have a role in the pathogenesis of NAFLD. In this article, we present an overview of the basic information on NAFLD, particularly GTs and glycosylation modification of certain molecules and their association with NAFLD pathogenesis. In addition, the effects and mechanisms of some GTs in the development of NAFLD are summarized.

Geometric Design-based Dimensional Synthesis of a Novel Metamorphic Multi-fingered Hand with Maximal Workspace

Current research on robotic dexterous hands mainly focuses on designing new finger and palm structures,as well as developing smarter control algorithms.Although the dimensional synthesis of dexterous hands with traditional rigid palms has been carried out,research on the dimensional synthesis of dexterous hands with metamorphic palms remains insufficient.This study investigated the dimensional synthesis of a palm of a novel metamorphic multi-fingered hand,and explored the geometric design for maximizing the precision manipulation workspace.Different indexes were used to value the workspace of the metamorphic hand,and the best proportions between the five links of the palm to obtain the optimal workspace of the metamorphic hand were explored.Based on the fixed total length of the palm member,four nondimensional design parameters that determine the size of the palm were introduced;through the discretization method,the influence of the four design parameters on the workspace of the metamorphic hand with full-actuated fingers and under-actuated fingers was analyzed.Based on the analysis of the metamorphic multi-fingered hand,the symmetrical structure of the palm was designed,resulting in the largest workspace of the multi-fingered hand,and proved that the metamorphic palm has a massive upgrade for the workspace of underactuated fingers.This research contributed to the dimensional synthesis of metamorphic dexterous hands,with practical significance for the design and optimization of novel metamorphic hands.

Synergistic double-atom catalysts of metal-boron anchored on g-C_(2)N for electrochemical nitrogen reduction:Mechanistic insight and catalyst screening

The rational design of a novel catalytic center with a sound basis remains both challenging and rewarding for the electrochemical reduction of N2(e NRR),which has provided a feasible route for achieving clean and sustainable NH3production under ambient conditions.Herein,using density functional theory calculations,we demonstrate that hybrid metal(M)-boron(B)double-atom catalysts(DACs)embedded in gC_(2)N substrate(M-B@C_(2)N,M=3d,4d and 5d transition metals)can achieve both high catalytic activity and high selectivity in e NRR.The proposed M-B@C_(2)N DACs have exhibited impressive feasibility and stability thanks to the resilient and robust C_(2)N substrate with abundant pyridinic N atoms distributed among right-sized pore structures.Our results reveal that like the metal center,the embedded B atom can actively involve in N≡N bond activation viaπ*-backdonation mechanism concomitant with the substantial charge transfer to adsorbed*N2,leading to sizable NAN bond elongation.Accordingly,both adsorption energy and NAN bond length of*N2can be employed as catalytic descriptors for predicting e NRR activity in terms of the limiting potentials(UL).Using high-throughput screening method,we found that six M-B@C_(2)N candidates have stood out as the outstanding electrocatalysts for driving e NRR,namely,M=Ti(UL=0 V),Mo(UL=0 V),Nb(UL=-0.04 V),W(UL=-0.23 V),Zr(UL=-0.26 V),V(UL=-0.28 V).The underlying origin is attributed to the balanced and constrained N-affinity of M-B dual site working in synergy,which can thus be used as one important guide of catalyst design.

Tunica vaginalis testis metastasis as the first clinical manifestation of pancreatic adenocarcinoma:A case report

BACKGROUND Metastases from pancreas or ampullary malignancies are common,but the spread to testicle and paratesticular tissue is exceedingly rare.To the best of our knowledge,fewer than 30 cases have been reported in the literature.More rarely,metastasis to tunica vaginalis testis occurs without involvement of the testes and epididymis.CASE SUMMARY A 65-year-old male who complained of painless swelling of the left scrotum for over 1 wk was referred to the Department of Urology.Scrotal ultrasound showed left testicular hydrocele with paratesticular masses.Chest computed tomography revealed lung metastasis and enlarged left supraclavicular lymph node.The blood tumor markersalpha-fetoprotein,human chorionic gonadotropin,and serum lactate dehydrogenase were withinnormal limits.The preoperative diagnosis was left testicular tumor with lung metastasis.Then radical orchidectomy of the left testicle and high ligation of the spermatic cord were performed,and postoperative histopathology suggested metastatic tumors that was confirmed by an abdominal computed tomographic scan.The positive computed tomography findings,in conjunction with the expression of cytokeratin 7(CK7),CK20,CK5/6,and absence of expression of Wilms’tumor suppressor gene 1,calretinin,melanocyte,prostate-specific antigen,thyroid transcription factor-1,GATA binding protein 3,caudal type homeobox 2,and napsinA supported the diagnosis of pancreatic adenocarcinoma.The outcome of this patient was unsatisfactory,and he died 3 mo later.CONCLUSION This case suggests that pancreatic metastatic carcinoma must be considered in the differential diagnosis of scrotal enlargement.The advanced age of the patient wassuggestive of a secondary testicular tumor.In addition,careful physical examination and ultrasonography as well as radiological examination have become a standard modality.

Research on the Design and Implementation of Detection System of Nutz Framework Meteorological Metrical Device

In people’s daily life, the role of weatherforecast is self-evident. However, the accuracy offorecasting is based on the accuracy and reliability ofmeteorological data which depends on the sensitivityof meteorological device. Therefore, an importantduty of the detection institution of meteorologicalmetrical device is to have the effective detectionof meteorological device, so as to ensure a highsensitivity of the device. However, the meteorologicaldevice used by some meteorological bureaus is nottechnologically advanced and the device detectionmode is too old, which cannot meet the new regulationsissued by the China Meteorological Administration.So it is necessary for the meteorological bureau todevelop a set of devices that can easily meet the newmeteorological measurement requirements, which is ofgreat significance to ensure the accurate measurementof meteorological data.

Satellite constellation design with genetic algorithms based on system performance

Satellite constellation design for space optical systems is essentially a multiple-objective optimization problem. In this work, to tackle this challenge, we first categorize the performance metrics of the space optical system by taking into account the system tasks（i.e., target detection and tracking）. We then propose a new non-dominated sorting genetic algorithm（NSGA） to maximize the system surveillance performance. Pareto optimal sets are employed to deal with the conflicts due to the presence of multiple cost functions. Simulation results verify the validity and the improved performance of the proposed technique over benchmark methods.

机械加工过程中的切削力分析与控制策略研究

围绕“机械加工过程中的切削力分析与控制策略研究”展开研究,对不同材料和刀具参数下的切削力进行了系统测量,并建立了相应的力学模型。基于分析结果提出了一种有效的切削力控制策略,旨在优化加工过程中的力学性能。通过引入先进的控制算法和实时监测技术,实现了对切削力的精准调控,提高了加工效率和产品质量。最后通过仿真验证和实际应用测试,证明了所提策略在提高切削效能的同时,有效延长了工具寿命,为机械加工领域的自动化生产提供了可行的解决方案。

“工匠精神”融入金工实习教学的实践研究

文章研究以探索以“工匠精神”为导向,将思政元素融入金工实习教学的方法。首先,分析了工匠精神的重要性及其内涵。其次,探讨了在金工实习课程中培养工匠精神的必要性。然后,探索了将“工匠精神”作为思政元素融入金工实习教学中所面临的困境。最后,提出了培养“工匠精神”的策略,以提升金工实习的育人功能,增强学生的职业自信心,激发学生的积极性和兴趣,为制造业培养优秀人才做出贡献。

基于类比分析法的光伏电站发电能力评估模型研究

在光伏电站建设前期做可行性评估的过程中,需要对拟建光伏电站的发电量进行理论上的预测,以此来测算项目的投资收益率,进而评估项目是否值得投资建设。光伏电站发电能力评估的准确性受限于气象数据的准确性及光伏电站系统效率(PR)评估的准确性。由于环境复杂性高、实际测量难度大等原因,导致无法获得拟建光伏电站真实的气象数据及准确的PR。将拟建光伏电站周边的光伏电站作为参考,引入参考光伏电站的历史发电数据,结合参考光伏电站与拟建光伏电站的太阳辐射量差异、PR差异,提出了一种基于类比分析法的光伏电站发电能力评估模型。通过建立评估模型,解耦气象因素偏差对光伏电站PR的影响,分析各因素导致的评估模型的偏差范围,并采用3组光伏电站对照组的发电数据对评估模型的准确性进行了验证。研究结果表明:气象因素偏差对光伏电站PR的最大影响为1.5972%。采用该评估模型测算得到的3组光伏电站对照组的年等效利用小时数评估偏差皆控制在3.00%以内,平均偏差为1.21%,远低于采用PVsyst软件测算得到的年等效利用小时数的平均偏差。表明该评估模型具有良好地准确度,可作为光伏电站建设时评估其发电量的实用且有效的方法。

柔性光伏支架场景下双面双玻光伏组件隐裂风险的实验研究

针对柔性光伏支架(下文简称为“柔性支架”)的结构响应导致双面双玻光伏组件产生隐裂的风险进行评估,首先介绍了柔性支架的结构响应及光伏组件隐裂判定标准,然后选择最适合在柔性支架场景下应用的主流双面双玻光伏组件作为实验对象,设计了可复现柔性支架结构响应工况的振动台,构建了柔性支架的结构响应与双面双玻光伏组件隐裂之间关系的实验模型;针对整体振动、翻转振动和扭曲振动3种工况下不同振动幅度、振动频率、振动次数的双面双玻光伏组件的隐裂情况进行实验分析,对柔性支架场景下实验工况与自然环境极端风荷载实际工况时双面双玻光伏组件的振动情况进行了对比,并验证了双面双玻光伏组件在全寿命周期内不发生隐裂的可靠性。研究结果表明:自然环境极端风荷载实际工况下,在柔性支架本身结构及光伏组件的边框结构不发生破坏的前提下,双面双玻光伏组件在全寿命周期内不会发生隐裂。

乡村振兴背景下乡村治理碎片化困境与策略

乡村治理是国家治理体系的重要组成部分,也是实现乡村振兴的关键环节。当前,乡村治理面临着严重的碎片化困境,主要表现在治理理念碎片化、治理主体碎片化、治理资源碎片化与治理监管碎片化四个方面,严重影响了乡村治理综合效能的提升。整体性治理作为一种新的治理模式与治理工具,不仅契合了乡村治理“公共性”的价值诉求,还契合了乡村治理对协调、整合和信任机制的需要。基于此,应借助整体性治理理论的视角,通过树立整体性治理理念,培育治理文化;明确主体角色定位,实现多元治理主体共治;整合农村治理资源,提升乡村综合治理效能;完善监督管理机制,提升乡村治理整体绩效,从而破解乡村治理碎片化困境。

超声造影定量分析颈动脉斑块预测缺血性脑卒中复发

目的探讨超声造影(CEUS)定量分析颈动脉斑块新生血管预测缺血性脑卒中(IS)复发的价值。方法对150例首次临床诊断IS且伴颈动脉斑块患者行CEUS,根据随访12个月是否出现IS复发分为复发组(n=64)和未复发组(n=86);比较2组一般资料及CEUS时间-强度曲线(TIC)相关参数,包括始增时间、峰值时间、基线强度、强度峰值、增强强度值(EI)、上升时间、斜率及强度比值(Ratio)的差异,分析IS复发危险因素;采用ROC曲线法分析TIC相关参数预测IS复发的诊断效能。结果复发组患者年龄、高血压、斑块强度峰值、EI值、斜率及Ratio值与未复发组差异均有统计学意义(P均<0.05)。EI值、Ratio值和高血压为IS复发的独立危险因素(P均<0.05)。EI值、Ratio值预测IS复发的AUC分别为0.81、0.80(Z=1.13,P=0.26)。结论CEUS能有效检出颈动脉斑块内新生血管及其密度,对预测IS复发有一定参考价值。

棚室大白菜品种栽培比较

为筛选适宜石阡县和织金县栽培的棚室春早熟大白菜品种,引进7个大白菜品种进行栽培比较,研究不同品种大白菜的生育期、农艺性状及产量、品种间发病情况等指标。结果表明,黔白6号、京春早、津宝2号、中白50和健春均有早熟性;津宝1号株型较大且长势健壮;健春、天白80单株净质量大(1.45、1.41 kg),小区净产量高(58.2、56.4 kg),与黔白6号差异不显著,而与津宝1号、京春早、津宝2号、中白50存在极显著差异;发病率较低的品种为健春和黔白6号,京春早和天白80发病率稍高、抗病性差。研究表明,健春、黔白6号在发病率、单株产量、小区净产量等农艺性状综合表现较好,2个品种可在石阡县和织金县推广栽培。

1-MCP处理对竹荪蛋采后生理及保鲜效果的影响

以采自贵州省织金县茶店乡和黔西市金碧镇皂角林下仿野生栽培的新鲜竹荪蛋为试材,在4℃冷藏条件下,研究了不同浓度1-甲基环丙烯(1-MCP)熏蒸处理对竹荪蛋贮藏过程中品质与生理生化指标的影响。结果表明:贮藏到20 d时,经20μL/L 1-MCP处理的失重率最低为16.58%、内聚性值最高为0.71、弹性值最高为3.24 N、腐烂率最低为25.00%,说明20μL/L 1-MCP处理对抑制竹荪蛋失重率的上升、保持竹荪蛋的内聚性、维持竹荪蛋菌体的弹性和降低竹荪蛋腐烂率的效果均最好;20μL/L 1-MCP处理的白度值从贮藏初期到末期各阶段的变化最小,说明其能够较好地维持竹荪蛋的白度值;5和20μL/L 1-MCP处理在整个贮藏期能维持较低的PPO活性,说明高浓度1-MCP处理能够有效抑制竹荪蛋的PPO活性;当贮藏至20 d时,1μL/L 1-MCP处理的硬度值最高达17.27 N、咀嚼性值最高为40.94 mj,说明1μL/L 1-MCP处理对维持竹荪蛋硬度和抑制竹荪蛋咀嚼性降低的效果最好。综合考虑,红托竹荪蛋在4℃条件下贮藏时,以20μL/L 1-MCP处理的效果最好。

不同保鲜剂对竹荪蛋的保鲜效果

本文研究了不同保鲜剂处理对新鲜竹荪蛋贮藏期间保鲜效果的影响。分别以不同浓度的壳聚糖、卡拉胶和抗坏血酸为涂膜剂对竹荪蛋进行涂膜处理,以蒸馏水为对照,用PE保鲜袋包装后置于4℃条件下贮藏,研究竹荪蛋贮藏期间失重率、色差值、可溶性蛋白含量、游离氨基酸含量和PPO活性等指标的变化。研究表明:各个保鲜剂的最佳处理浓度分别为壳聚糖1.2%、卡拉胶0.1%、抗坏血酸的浓度0.1%,3种保鲜剂均能减缓失重率的上升,抑制PPO活性,使PPO活性峰值延缓出现4d,壳聚糖和卡拉胶处理对抑制蛋白质分解为游离氨基酸有一定效果,抗坏血酸处理能较好的保持竹荪蛋的色泽,维持可溶性蛋白含量。综合评价3种保鲜剂对竹荪蛋的保鲜效果,0.1%浓度抗坏血酸保鲜效果最佳,贮藏结束后失重率为0.64%,白度值为50.73,可溶性蛋白含量为3.05 mg/g,游离氨基酸含量为327.73 mg/100 g。PPO活性为1.86ΔOD420/(min·g),均优于对照组。