Highly Sensitive Ammonia Gas Sensors at Room Temperature Based on the Catalytic Mechanism of N,C Coordinated Ni Single-Atom Active Center

Significant challenges are posed by the limitations of gas sensing mechanisms for trace-level detection of ammonia(NH3).In this study,we propose to exploit single-atom catalytic activation and targeted adsorption properties to achieve highly sensitive and selective NH3 gas detection.Specifically,Ni singleatom active sites based on N,C coordination(Ni-N-C)were interfacially confined on the surface of two-dimensional(2D)MXene nanosheets(Ni-N-C/Ti_(3)C_(2)Tx),and a fully flexible gas sensor(MNPE-Ni-N-C/Ti_(3)C_(2)Tx)was integrated.The sensor demonstrates a remarkable response value to 5 ppm NH3(27.3%),excellent selectivity for NH3,and a low theoretical detection limit of 12.1 ppb.Simulation analysis by density functional calculation reveals that the Ni single-atom center with N,C coordination exhibits specific targeted adsorption properties for NH3.Additionally,its catalytic activation effect effectively reduces the Gibbs free energy of the sensing elemental reaction,while its electronic structure promotes the spill-over effect of reactive oxygen species at the gas-solid interface.The sensor has a dual-channel sensing mechanism of both chemical and electronic sensitization,which facilitates efficient electron transfer to the 2D MXene conductive network,resulting in the formation of the NH3 gas molecule sensing signal.Furthermore,the passivation of MXene edge defects by a conjugated hydrogen bond network enhances the long-term stability of MXene-based electrodes under high humidity conditions.This work achieves highly sensitive room-temperature NH3 gas detection based on the catalytic mechanism of Ni single-atom active center with N,C coordination,which provides a novel gas sensing mechanism for room-temperature trace gas detection research.

Risk Factors and Predictive Nomogram for Survival in Elderly Patients with Brain Glioma

Objective To determine the factors that contribute to the survival of elderly individuals diagnosed with brain glioma and develop a prognostic nomogram.Methods Data from elderly individuals(age≥65 years)histologically diagnosed with brain glioma were sourced from the Surveillance,Epidemiology,and End Results(SEER)database.The dataset was randomly divided into a training cohort and an internal validation cohort at a 6:4 ratio.Additionally,data obtained from Tangdu Hospital constituted an external validation cohort for the study.The identification of independent prognostic factors was achieved through the least absolute shrinkage and selection operator(LASSO)and multivariate Cox regression analysis,enabling the construction of a nomogram.Model performance was evaluated using C-index,ROC curves,calibration plot and decision curve analysis(DCA).Results A cohort of 20483 elderly glioma patients was selected from the SEER database.Five prognostic factors(age,marital status,histological type,stage,and treatment)were found to significantly impact overall survival(OS)and cancer-specific survival(CSS),with tumor location emerging as a sixth variable independently linked to CSS.Subsequently,nomogram models were developed to predict the probabilities of survival at 6,12,and 24 months.The assessment findings from the validation queue indicate a that the model exhibited strong performance.Conclusion Our nomograms serve as valuable prognostic tools for assessing the survival probability of elderly glioma patients.They can potentially assist in risk stratification and clinical decision-making.

Visible-to-near-infrared photodetectors based on SnS/SnSe_(2)and SnSe/SnSe_(2)p−n heterostructures with a fast response speed and high normalized detectivity

The emergent two-dimensional(2D)material,tin diselenide(SnSe_(2)),has garnered significant consideration for its potential in image capturing systems,optical communication,and optoelectronic memory.Nevertheless,SnSe_(2)-based photodetection faces obstacles,including slow response speed and low normalized detectivity.In this work,photodetectors based on SnS/SnSe_(2)and SnSe/SnSe_(2)p−n heterostructures have been implemented through a polydimethylsiloxane(PDMS)−assisted transfer method.These photodetectors demonstrate broad-spectrum photoresponse within the 405 to 850 nm wavelength range.The photodetector based on the SnS/SnSe_(2)heterostructure exhibits a significant responsivity of 4.99×10^(3)A∙W^(−1),normalized detectivity of 5.80×10^(12)cm∙Hz^(1/2)∙W^(−1),and fast response time of 3.13 ms,respectively,owing to the built-in electric field.Meanwhile,the highest values of responsivity,normalized detectivity,and response time for the photodetector based on the SnSe/SnSe_(2)heterostructure are 5.91×10^(3)A∙W^(−1),7.03×10^(12)cm∙Hz^(1/2)∙W−1,and 4.74 ms,respectively.And their photodetection performances transcend those of photodetectors based on individual SnSe_(2),SnS,SnSe,and other commonly used 2D materials.Our work has demonstrated an effective strategy to improve the performance of SnSe_(2)-based photodetectors and paves the way for their future commercialization.

Combined transarterial chemoembolization and tislelizumab for patients with unresectable hepatocellular carcinoma

BACKGROUND Hepatocellular carcinoma(HCC)often presents as unresectable,necessitating effective treatment modalities.Combining transarterial chemoembolization(TACE)with immunotherapy and targeted therapy has shown promise,yet real-world evidence is needed.AIM To investigate effectiveness and safety of TACE with tislelizumab±targeted therapy for unresectable HCC in real-world setting.METHODS This retrospective study included patients with unresectable HCC receiving combined treatment of TACE and tislelizumab.The clinical outcomes included progression-free survival(PFS),overall survival(OS),objective response rate(ORR),and disease control rate(DCR).All patients were evaluated according to the mRECIST criteria.The adverse event(AE)was also assessed.RESULTS In this study of 56 patients with median follow-up of 10.9 months,7 had previous immunotherapy.Tislelizumab was administered before TACE in 21(37.50%)and after in 35(62.50%)patients,with 91.07%receiving concurrent targeted therapy.Median PFS was 14.0(95%CI:7.0-18.00)months,and OS was 28(95%CI:2.94-53.05)months.Patients with prior immunotherapy had shorter PFS(6 vs.18 months,P=0.006).Overall ORR and DCR were 82.14%and 87.50%.Grade≥3 treatment-related AEs included increased alanine aminotransferase(8.93%),aspartate aminotransferase(10.71%),and total bilirubin(3.57%).CONCLUSION The combination of TACE and tislelizumab,with or without targeted therapy,demonstrated promising efficacy and safety in unresectable HCC,especially in immunotherapy-naive patients,warranting further prospective validation studies.

Analysis of a Rare Heavy Rain Weather Process in Autumn in Ulanqab City

Based on the conventional observation data and NCEP/NCAR reanalysis data,the circulation situation,influencing systems and causes of the heavy rain during September 20-21,2010 in Ulanqab City were analyzed from the evolution process of weather circulation situation and the changes of various physical quantity fields.The results show that there was an obvious frontal zone between 45-52°N,which brought strong cold air.The transport of warm and humid air outside the subtropical high and typhoon was the main water vapor source of the strong precipitation,and the southwest jet at 700 hPa transported abundant water vapor.There was a broad inverted trough to the south of 45°N,with a central value of 1000.0 hPa.Ulanqab City was on the top of the inverted trough,stable and less moved,which was conducive to the occurrence of systematic heavy precipitation.The rainstorm was a strong precipitation process caused by the intersection of cold air brought by the southward movement of the upper frontal zone and warm and humid air outside the subtropical high.After the precipitation,the invasion of strong cold air brought frost and cold wave weather to Ulanqab City.

基于有源功率因数校正的直流充电桩控制策略研究

针对常规电动汽车充电桩存在的引发电网产生大量谐波污染、功率因数低、输出不稳定等问题,在直流充电桩中引入有源功率因数校正(APFC)技术,以实现优质电能的输出。采用空间矢量脉宽调制(SVPWM)算法的双闭环直接电流控制,对APFC主电路参数及其PI控制器参数进行设计,并分别利用MATLAB/Simulink和搭建试验平台进行仿真和试验验证,仿真和试验结果表明,提出的控制方法可有效减小谐波污染,提高功率因数和电能质量。

面向WSN的无人机水域监测系统研究与应用

针对水域水质监测数据收集难度较大、数据传输成本高、不灵活等问题,利用无人机的高机动性设计一种在WSN水域监测中以无人机充当移动汇聚节点,通过无线传输数据,来高效灵活地收集监测节点数据的新型系统。根据此系统的特性在传统的路径规划算法上对无人机的飞行路径做进一步的优化研究。实验结果表明,该系统稳定、成本低、实时性强、灵活性高,可准确有效地收集监测节点的数据。

超空泡航行体时滞特性分析

水下航行体在空泡的包裹下运行,能够减小阻力从而提高速度。在运行过程中航行体的尾部会与空泡壁碰撞产生滑行力。由于空泡具有时滞效应,影响航行体尾部滑行力的计算。针对空泡的时滞效应,对比研究了时滞特性对超空泡航行体控制性能的影响。结果表明,时滞在定性上对性能不会引起质的变化,系统设计时可采用没有时滞的滑行力模型以简化计算,设计后再用时滞模型来进行仿真验证。

基于多因素聚类选择的Android应用程序分类风险评估方法

大多数现有的Android应用程序风险评估根据经验直接指定因素的权重,通过统计少量因素的使用频率来计算安全风险。提出一种新的Android应用风险评估方法,能够同时提供定量和定性评估。该方法融合系统权限、API调用、Intent Filter的action属性以及数据流等多种风险因素,基于因素的风险分类与加成进行风险赋值,基于层次聚类对因素子集进行权重分配。实验表明,评估结果能够有效地反映Android应用程序的真实安全风险。

基于深度神经网络的Android恶意软件检测方法

Android系统正日益面临着恶意软件的攻击威胁。针对支持向量机等传统机器学习方法难以有效进行大样本多分类的恶意软件检测,提出一种基于深度神经网络的Android恶意软件检测与家族分类方法。该方法在全面提取应用组件、Intent Filter、权限、数据流等特征基础上,进行有效的特征选择以降低维度,基于深度神经网络进行面向恶意软件的大样本多分类检测。实验结果表明,该方法能够进行有效检测和分类,良性、恶意二分类精度为97.73%,家族多分类精度可达到93.54%,比其他机器学习算法有更好的分类效果。

野外巡检机器人的控制器

为了提高巡检机器人在转弯及有坡度路况下的平稳性与快速性,设计了一种差速控制器。前轮控制速度实现转向,后轮承担驱动功能。其中采用电流环为滞环控制、速度环为自适应模糊PI控制的双闭环控制策略,模拟巡检平台硬件、软件采用模块化设计。在MATLAB环境下进行仿真实验,并在模拟平台进行实验验证。结果表明,该系统具有良好的运行效果。

Mimics10.01三维重建分割方法的探究

目的对Mimics10.01软件在三维重建中的3种分割方式进行比较,为该软件在基础医学等医学领域的开发应用提供新的思路与方法。方法选取100例无器质性病变的成年男性的肝脏器官,利用64位螺旋CT的薄层扫描技术,基于1.00mm层厚,1026层人体肝脏的连续断层图像,将其直接以Dicom格式的原始图像读入Mimics软件中,采用'直接分割'、'加法分割'和'减法分割'3种模型分割技术,获得肝脏的轮廓及肝内血管系统的蒙板,将蒙板内相邻像素连接并重组成图像后获得三维立体模型。结果3种三维重建方法得到的肝脏模型轮廓清楚,可实现旋转,方便角度、体积测量,并且可以得到任何重建模型的断面。'直接分割'方法能够较轻易地重建肝脏的血管主干及大的分支;'加法分割'方法可以在某个局部主动将几条血管的2级、3级甚至终末分支实现重建;'减法分割'可以将视野内的几乎所有血管的分支分割出来实现精确重建,三种方法重建出肝动脉、肝门静脉和肝静脉的个数之间比较,有显著性差异(<0.05)。结论以上3种方法各有优、缺点,其中,'减法分割'方法重建比其他两种方法信息丢失少,效果更加逼真,是目前可实现的最佳分割方式。

Hierarchically mesoporous carbon spheres coated with a single atomic Fe-N-C layer for balancing activity and mass transfer in fuel cells

Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The high-cost PGM catalyst in fuel cells can be replaced by earth-abundant transition-metalbased catalysts,that is,an Fe-N-C catalyst,which is considered one of the most promising alternatives.However,the performance of the Fe-N-C catalyst is hindered by the low catalytic activity and poor stability,which is caused by insufficient active sites and the lack of optimization of the triple-phase interface for mass transportation.Herein,a novel Fe–N–C catalyst consisting of mono-dispersed hierarchically mesoporous carbon sphere cores and single Fe atom-dispersed functional shells are presented.The synergistic effect between highly dispersed Fe-active sites and well-organized porous structures yields the combination of high ORR activity and high mass transfer performance.The half-wave potential of the catalyst in 0.1M H_(2)SO_(4) is 0.82 V versus reversible hydrogen electrode,and the peak power density is 812 mW·cm^(−2) in H_(2)–O_(2) fuel cells.Furthermore,it shows superior methanol tolerance,which is almost immune to methanol poisoning and generates up to 162 mW·cm^(−2) power density in direct methanol fuel cells.

Single-Crystalline In Ga As Nanowires for Room-Temperature High-Performance Near-Infrared Photodetectors

In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor deposition method.Photoluminescence measurements indicate the In Ga As nanowires have strong light emission in near-infrared region. For the first time, photodetector based on as-grown In Ga As nanowires was also constructed. It shows good light response over a broad spectral range in infrared region with responsivity of 6.5×10~3 AW^(-1) and external quantum efficiency of 5.04×10~5%. This photodetector may have potential applications in integrated optoelectronic devices and systems.

Expression of Outer Capsid Protein VP5 of Grass Carp Reovirus in E.coli and Analysis of its Immunogenicity

Grass carp reovirus (GCRV) is a tentative member of the Aquareovirus genus in the family Reoviridae. The mature virion comprises 11 dsRNA genomes enclosed by two concentric icosahedral proteins shells that is comprised of five core proteins and two outer capsid proteins. The genome sequence and 3D structure demonstrate there is a higher level of sequence homology in structural proteins between GCRV and mammalian orthoreoviruses (MRV) compared to other members of the family. To understand the pathogenesis of GCRV infection, the outer capsid protein VP5, a homology of the μ1 protein of MRV, was expressed in E.coli. It was found that the recombinant VP5 was highly expressed, and the expressed His-tag fusion protein was involved in the formation of the inclusion body. Additionally, specific anti-VP5 serum was prepared from purified protein and western blot demonstrated that the expressed protein was able to bind immunologically to rabbit anti GCRV particle serum and the immunogenicity was determined by ELISA assay. Additional experiments in investigating the functional properties of VP5 will further elucidate the role of the GCRV outer capsid protein VP5 during entry into host cells, and its interaction among viral proteins and host cells during the infection process.

Outstanding Humidity Chemiresistors Based on Imine-Linked Covalent Organic Framework Films for Human Respiration Monitoring

Human metabolite moisture detection is important in health monitoring and non-invasive diagnosis.However,ultra-sensitive quantitative extraction of respiration information in real-time remains a great challenge.Herein,chemiresistors based on imine-linked covalent organic framework(COF)films with dual-active sites are fabricated to address this issue,which demonstrates an amplified humidity-sensing signal performance.By regulation of monomers and functional groups,these COF films can be pre-engineered to achieve high response,wide detection range,fast response,and recovery time.Under the condition of relative humidity ranging from 13 to 98%,the COFTAPB-DHTA film-based humidity sensor exhibits outstanding humidity sensing perfor-mance with an expanded response value of 390 times.Furthermore,the response values of the COF film-based sensor are highly linear to the relative humidity in the range below 60%,reflecting a quantitative sensing mechanism at the molecular level.Based on the dual-site adsorption of the(-C=N-)and(C-N)stretching vibrations,the revers-ible tautomerism induced by hydrogen bonding with water molecules is demonstrated to be the main intrinsic mechanism for this effective humidity detection.In addition,the synthesized COF films can be further exploited to effectively detect human nasal and oral breathing as well as fabric permeability,which will inspire novel designs for effective humidity-detection devices.

Expression and Identification of Inclusion Forming-related Domain of NS80 Nonstructural Protein of Grass Carp Reovirus

Grass carp reovirus （GCRV）, a double stranded RNA virus that infects aquatic animals, often with disastrous effects, belongs to the genus Aquareovirus and family Reoviridea. Similar to other reoviruses, genome replication of GCRV in infected cells occurs in cytoplasmic inclusion bodies, also called viral factories. Sequences analysis revealed the nonstmctural protein NS80, encoded by GCRV segment 4, has a high similarity with μNS in MRV（Mammalian orthoreovimses）, which may be associated with viral factory formation. To understand the function of the μNS80 protein in virus replication, the initial expression and identification of the immunogenicity of the GCRV NS80 protein inclusion forming-related region （335-742） was investigated in this study. It is shown that the over-expressed fusion protein was produced by inducing with IPTG at 28℃. In addition, serum specific rabbit antibody was obtained by using super purified recombinant NS80（335-742） protein as antigen. Moreover, the expressed protein was able to bind to anti-his-tag monoclonal antibody （mouse） and NS80〈335.742） specific rabbit antibody. Further western blot analysis indicates that the antiserum could detect NS80 or NS80C protein expression in GCRV infected cells. This data provides a foundation for further investigation of the role of NS80 in viral inclusion formation and virion assembly.

Molecular Characterization of Nonstructural Protein NS38 of Grass Carp Reovirus

Viral nonstructural proteins in both enveloped and non-enveloped viruses play important roles in viral replication. Protein NS38 of Grass carp reovirus (GCRV), has been deduced to be a non-structural protein, and, consistent with other reoviruses, is considered to cooperate with the NS80 protein in viral particle assembly. To investigate the molecular basis of the role of NS38, a complete protein was expressed in E.coli for the first time. It was found that there is a better expression of NS38 induced with IPTG at 28 ℃ rather than 37 ℃. In addition, the antiserum of NS38 prepared with purified fusion protein and injected into rabbit could be used for detecting NS38 protein expression in GCRV infected cell lysate, while there is not any reaction crossed with purified virus particle, confirming NS38 is not a component of the viral structural protein. The result reported in this study will provide evidence for further viral protein-protein and protein-RNA interaction in dsRNA viruses replication.

Influence of Ce and Mn addition on α-Fe morphology in recycled Al-Si alloy ingots

The influence of Ce or Ce and Mn combined additions on the morphology of a-Fe phases in recycled AloSi alloys was experimentally investigated by microstructure observation and room temperature tensile testing. It is found that Ce modifies the morphology of a-Fe phase from the large Chinese script-like into the individual and fine nodular shape. A combined addition of Ce and Mn results in the promotion of primary a-Fe formation, and their size increases considerably with the increase in Ce content. The mechanism of the above morphological changes was discussed in accordance with the nucleation and growth of a-Fe phase during solidification.

Functional Analyses of Mammalian Reovirus Nonstructural Protein μNS

Genome replication of reovirus occurs in cytoplasmic inclusion bodies called viral factories or viroplasms. The viral nonstructural protein uNS, encoded by genome segment M3, is not a component of mature virions, but is expressed to high levels in infected cells and is concentrated in the infected cell factory matrix. Recent studies have demonstrated that uNS plays a central role in forming the matrix of these structures, as well as in recruiting other components to them for putative roles in genome replication and particle assembly.