碳系导电油墨的导电性能研究

将碳纳米管作为导电填料,加入喷墨打印专用墨水,制备成新型碳系导电油墨,并加入助剂等添加剂调节油墨的综合性能。通过实验,研究分析了碳系导电油墨中碳纳米管的质量分数、形成碳系导电油墨涂层的喷涂层数,油墨涂层喷涂成型后的静置时间、电极铜片与油墨涂层的接触面积、油墨涂层的基底材料等对其导电性能的影响。结果表明,碳系导电油墨的电阻随着碳纳米管质量分数和喷涂层数的增加而下降;一定质量分数的碳系导电油墨,喷涂3层以上时,涂层电阻对喷涂完成后的静置时间效应不敏感;对于一定特性的碳系导电油墨涂层,总电阻值与接触面积的倒数值具有线性关系;不同的涂层基底材料对导电涂层的导电性能有影响。

基于双目视觉的板材平面测量研究

针对传统人工测量板材尺寸精度较低、工作量大、易导致板材表面受损等局限,基于双目视觉技术设计了一种板材尺寸视觉测量系统;通过双目相机采集棋盘格图像,采用MATLAB进行相机标定和图像校正,拍摄左右图像并通过半全局立体匹配算法(SGM,semi global matching)进行特征点立体匹配,重建出目标三维点云模型;为提高目标特征点坐标获取的准确性,提出基于HARRIS的亚像素检测方法;采用区域生长算法结合膨胀和腐蚀操作提取板材表面轮廓,根据三角测量原理计算出板材轮廓上各点的三维坐标从而实现板材的尺寸测量,并进行点云重建增强三维展示效果;实践结果表明亚像素检测方法在角点提取上存在优势,在实际板材测量应用中实现了高精度尺寸测量,满足了工业测量需求。

新工科和工程教育认证背景下机制专业培养目标的确立与评价体系探索

随着新一轮科技和产业变革的到来,亟须具有创新能力和工程能力的高素质复合型人才。文章以机械设计制造及其自动化(机制)专业为例,研究在新工科和工程教育认证背景下地方高校如何定位培养目标,分别从培养目标与学校定位的关系、专业人才培养定位的关系以及社会经济发展需要的关系确立机制专业培养目标,并形成了培养目标的合理性评价体系,从而对培养目标和课程体系进行及时修订和调整,最终培养出适应社会发展需求的高素质机械工程技术人才。

Protein Containing the GGDEF Domain Affects Motility and Biofilm Formation in Vibrio cholerae and is Negatively Regulated by Fur and HapR

Objective This study aimed to investigate whether the VCA0560 gene acts as an active diguanylate cyclase(DGC)in Vibrio cholerae and how its transcription is regulated by Fur and Hap R.Methods The roles of VCA0560 was investigated by utilizing various phenotypic assays,including colony morphological characterization,crystal violet staining,Cyclic di-GMP(c-di-GMP)quantification,and swimming motility assay.The regulation of the VCA0560 gene by Fur and Hap R was analyzed by luminescence assay,electrophoretic mobility shift assay,and DNase I footprinting.Results VCA0560 gene mutation did not affect biofilm formation,motility,and c-di-GMP synthesis in V.cholerae,and its overexpression remarkably enhanced biofilm formation and intracellular c-di-GMP level but reduced motility capacity.The transcription of the VCA0560 gene was directly repressed by Fur and the master quorum sensing regulator Hap R.Conclusion Overexpressed VCA0560 functions as an active DGC in V.cholerae,and its transcription is repressed by Fur and Hap R.

TaqMan-rRT-PCR检测猪霍乱沙门菌方法的建立和实验室评价

目的基于猪霍乱沙门菌血清型特异性基因,建立TaqMan逆转录实时聚合酶链反应(TaqMan-rRT-PCR)检测猪霍乱沙门菌的方法。方法利用基因组序列比对筛选到猪霍乱沙门菌特有的基因SC0358,通过普通PCR及利用多种血清型沙门菌及非沙门菌菌株共计145株,评价该方法的菌株特异性,针对该基因设计TaqMan-rRT-PCR检测方法的引物,优化反应条件,建立针对该靶基因的TaqMan-rRT-PCR检测方法,以纯菌及血液模拟标本RNA为模板进行敏感性检测。结果利用该方法检测26株猪霍乱沙门菌均为阳性,其余菌株扩增均阴性,对纯菌RNA检测中,TaqMan-rRT-PCR的最低检测限度为5 fg/反应,约为10个拷贝/反应。对全血液模拟样品分析中,敏感性达25 cfu/mL。结论以猪霍乱沙门菌保守、特异基因SC0358建立的TaqMan-rRT-PCR方法,能够简便快捷区分猪霍乱沙门菌与其他血清型沙门菌,尤其能够区分与其有抗原式相同的丙型副伤寒沙门菌,此方法为猪霍乱沙门菌感染的快速诊断提供了简便的手段,可用于对猪霍乱沙门菌的早期诊断。

主动调压型微孔壁管道流场特性数值仿真

为降低因管道阻力而导致的流体能量损失,实现流体增速效果,提出了一种主动调压型微孔壁面管道模型.在该模型中,微孔中的空气为液相流体提供边界约束,从而降低其输运阻力.增速效果可以通过控制微孔中的空气压力而调整.利用流体力学仿真方法,对管道内的流场特性及增速效果开展数值计算.结果表明:与相同条件直管道相比,平均增速比可达到2%~6%,最高超过了12%;增速效果在液相入口压力较低时更为明显,并随着气相压力的增加呈现先增强后减弱的趋势;气相压力对流速的有效调节范围随液相入口压力的增大而减小.微孔口气液界面处呈现小曲率对称型弯月面时可以实现增速效果,但弯月面呈现非对称弧形曲面时实现最佳增速效果的情况也存在.

侧向流下局域电沉积的数值仿真研究

建立了侧向流下局域电沉积(LECD)仿真模型,对电沉积过程中铜离子的迁移与沉积形貌的形成过程进行了数值模拟,发现沉积反应前期在流域中央形成中央峰,之后沉积形貌不对称度增大,在中央峰上靠近上游侧逐渐形成一个前置峰。离子浓度分布结果说明中央峰主要是由阳极下方铜离子的沉积形成,前置峰则是由侧向流带来的铜离子沉积形成的。此外,增大侧向流的流速会加速前置峰的形成,并使其位置向下游移动。增大阴阳极间电压会导致前置峰更靠近上游,使不对称沉积提前发生。增大阴阳极间距会使模型区域内的沉积厚度明显增加,前置峰位置更靠近下游,并推迟不对称沉积现象的出现。采用侧向流辅助LECD有望为异形微形貌和微结构的制备提供新方法。

基于变步长局域电沉积法的纺锤形微铜柱制备

针对变截面微柱的局域电沉积制备开展了实验与仿真模拟,采用直径100μm的阳极针尖,通过改变连续提拉的步长制备了平均直径从92~293μm不等的自支撑微铜柱,探讨了提拉步长与铜柱直径的关系,进而提出了一种变步长局域电沉积方法,并成功制备了中部最大直径为164μm的变截面纺锤形微铜柱,同时利用COMSOL软件建立了数值仿真模型,分析了纺锤形铜柱形成的原因,可为基于局域电沉积法的复杂微结构制备提供参考。

基于Kinect的帕金森病步态不对称性识别方法

目的开发一种基于深度图像的非接触式帕金森病步态不对称性识别方法,以辅助医疗诊断和评估,解决穿戴型传感设备费用高、影响正常生活且检查流程复杂的问题。方法 2016年7月至8月,对帕金森病患者8例和健康人10例,采用Kinect V2.0采集行走6 m的运动数据;对左右脚参数滤波处理后分别聚类,使用相似度矩阵算法分别计算健康人和帕金森病患者相似度值;使用隐马尔科夫模型验证该方法的识别效果。结果所有患者左右脚参数聚类序列相似度小于健康人;从患者中提取的14条数据,成功识别12条(85.71%);从健康人中提取的46条数据,成功区别35条(76.09%)。结论基于左右脚位移过程中步态参数聚类结果不对称性的非接触式识别方法,对于帕金森病患者有一定识别效果。

Plasticity of Regulation of Mannitol Phosphotransferase System Operon by CRP-cAMP Complex in Vibrio cholerae

Objective The complex of the cyclic AMP receptor protein （CRP） and cAMP is an important transcriptional regulator of numerous genes in prokaryotes. The transport of mannitol through the phosphotransferase systems （PTS） is regulated by the CRP-cAMP complex. The aim of the study is to investigate how the CRP-cAMP complex acting on the mannitol PTS operon mtl of the Vibrio cholerae El Tot biotype. Methods The crp mutant strain was generated by homologous recombination to assess the need of CRP to activate the mannitol PTS operon of V. choleroe El Tor. Electrophoretic mobility shift assays （EMSA） and the reporter plasmid pBBRlux were used to confirm the role that the CRP-cAMP complex playing on the mannitol PTS operon intl. Results In this study, we confirmed that CRP is strictly needed for the activation of the mtl operon. We further experimentally identified five CRP binding sites within the promoter region upstream of the mannitol PTS operon mtl of the Vibrio cholerae El Tor biotype and found that these sites display different affinities for CRP and provide different contributions to the activation of the operon. Conclusion The five binding sites collectively confer the strong activation of mannitol transfer by CRP in V. choleroe, indicating an elaborate and subtle CRP activation mechanism.

Comparative Study of the Genetic Diversity, Antimicrobial Resistance, and Pathogenicity of Aeromonas Isolates from Clinical Patients and Healthy Individuals

Objective This study was performed to compare the genetic diversity,virulence,and antimicrobial resistance of Aeromonas strains isolated from patients and healthy individuals.Methods A total of 38 clinical strains and 19 strains from healthy individuals were isolated from the samples collected in Ma’anshan City,Anhui Province.Their taxonomy was investigated using concatenated gyrB-cpn60 sequences,and their resistance to 12 antibiotics was evaluated.The pathogenicity of these strains was examined through beta-hemolysis,protease activity,and virulence gene assays.Results The 57 Aeromonas strains were divided into 55 sequence types.Of these types,21 were novel,suggesting that their genetic diversity was high.These Aeromonas isolates could be divided into 7 species,and the positive rates of beta-hemolysis and protease activity were 49.1%and 73.7%,respectively.The detection rate of clinical patients in terms of beta-hemolysis and protease activity was higher than that of healthy individuals.Among the four most common Aeromonas strains,A.dhakensis had the highest detection rate of virulence genes.The multidrug resistance rate of the clinical isolates was much higher than that of the strains isolated from healthy individuals.Conclusions The taxonomy,virulence properties,and antibiotic resistance of Aeromonas isolates from patients differ from those of the isolates from healthy individuals.

Evaluation of Four Candidate VNTR Loci for Genotyping 225 Chinese Clinical Mycobacterium Tuberculosis Complex Strains

Objective To evaluate four candidate variable number tandem repeat （VNTR） loci for genotyping Mycobacterium tuberculosis complex strains. Methods Genomic sequences for two M. tuberculosis strains （CCDC5079 and CCDC5180） were generated, and using published sequence data, four candidate VNTR loci were identified. The VNTRs were used to genotype 225 Chinese clinical M. tuberculosis complex strains. The discriminatory power of the VNTRs was evaluated using BioNumerics 5.0 software. Results The Hunter-Gaston Index （HGI） for BJ1, BJ2, BJ3, and BJ4 loci was 0.634, 0.917, 0.697, and 0.910, respectively. Combining all four loci gave an HGI value of 0.995, thus confirming that the genotyping had good discriminatory power. The HGI values for BJ1, BJ2, BJ3, and BJ4, obtained from Beijing family strain genotyping, were 0.447, 0.878, 0.315, and 0.850, respectively. Combining all four loci produced an HGI value of 0.988 for genotyping the Beijing family strains. We observed unique patterns for M. boris and M. africanum strains from the four loci. Conclusion We have shown that the four VNTR loci can be successfully used for genotyping M. tuberculosis complex strains. Notably, these new loci may provide additional information about Chinese M. tuberculosis isolates than that currently afforded by established VNTR loci typing.

Master Quorum Sensing Regulator HapR Acts as A Repressor of the Mannitol Phosphotransferase System Operon in Vibrio cholerae

The phosphoenolpyruvate(PEP):carbohydrate phosphotransferase system(PTS)is widely used by bacteria to take up sugars or sugar derivatives;.PTS is usually composed of a histidine protein(HPr),enzyme I(EI),and several enzyme II(EII)proteins,such as EIIA,EIIB,EIIC,and EIID[1].

Comparison of Lipopolysaccharide and Protein Immunogens from Pathogenic Yersinia enterocolitica Bio-serotype 1B/O:8 and 2/O:9 using SDS-PAGE

Objective Yersinia enterocolitica is an extracellular pathogen and its related antigens interact with the host immune system. We investigated the difference in immunological characteristics between a highly pathogenic and poorly pathogenic strain of Y. enterocolitico. Methods We used SDS-PAGE and western blotting to characterize lipopolysaccharide （LPS）, Yersinio outer membrane proteins （Yops）, membrane proteins, and whole-cell proteins from poorly pathogenic Y. enterocolitico bio-serotype 2/0：9, isolated from China, and highly pathogenic bio-serotype 1B/O：8, isolated from Japan. Results These two strains of Y. enterocolitica had different LPS immune response patterns. Comparison of their Yops also showed differences that could have accounted for their differences in pathogenicity. The membrane and whole-cell proteins of both strains were similar; immunoblottting showed that the 35 kD and perhaps the 10 kD proteins were immunogens in both strains. Conclusion The major antigens of the two strains e and membrane proteins, as shown by comparing preparations. citing the host immune protein samples with response were the LPS reference and purified

基于噬菌体核酸检测霍乱弧菌的TaqMan-qPCR方法的建立

目的:建立一种基于噬菌体特异基因检测霍乱弧菌的TaqMan-qPCR方法。方法:基于VP1噬菌体的特异性基因gp46,建立TaqMan-qPCR方法,根据VP1潜伏期为50~60 min,爆发周期持续110~120 min,确定TaqMan-qPCR体系检测时间点。比对分析基于gp46与基于霍乱弧菌毒力基因ctxB建立的两种TaqMan-qPCR方法。结果:基于VP1噬菌体gp46成功建立TaqMan-qPCR反应,扩增效率接近93%,Ct值与样本中噬菌体浓度的相关系数高达0.998。TaqMan-qPCR和琼脂双层噬菌斑计数两种方法结果一致性很高,偏差低于2.45%。基于噬菌体gp46基因比基于毒力基因ctxB建立的TaqMan-qPCR方法的LB模拟样本灵敏度提高10倍,粪便及环境水体模拟样本灵敏度可提高100倍。结论:成功建立快速、高灵敏度和高特异性的TaqMan-qPCR方法,可实现在几小时内对含有霍乱弧菌疑似样本进行快速检测。

2017-2022年全国斑疹伤寒流行特征分析

目的分析我国2017—2022年斑疹伤寒流行特征,为制定斑疹伤寒防控策略提供科学依据。方法通过中国疾病预防控制信息系统传染病报告信息管理系统收集全国各省(自治区、直辖市)2017—2022年斑疹伤寒监测个案数据,运用描述流行病学方法进行分析。结果2017—2022年全国每年报告病例数(发病率)分别为929例(0.07/10万)、971例(0.07/10万)、1173例(0.08/10万)、1069例(0.08/10万)、1310例(0.09/10万)、1291例(0.09/10万),报告病例数及发病率呈波动增加趋势。2017—2022年每年有22~24个省份[309~342个县(区)]报告病例,主要分布于云南、广东、四川、安徽、湖北、山东、广西、湖南、河北9个省份(自治区),9个省份(自治区)每年合计报告病例数占全国病例数比例波动于85.56%~91.14%,其中云南、安徽、湖北省每年报告病例数及占全国报告病例数比例均呈增加趋势,山东省呈下降趋势。全国每年报告病例居前10位县(区)合计报告病例数(占全国病例数比例)分别为293例(31.53%)、284例(29.25%)、332例(28.30%)、400例(37.42%)、579例(44.20%)、636例(49.26%)。职业分布主要为农民、学生、散居儿童及幼托儿童,每年占报告病例数的比例分别波动于61.04%~65.60%、10.71%~15.43%、7.67%~9.80%。男女性别比波动于0.86∶1~1.02∶1之间。每年报告病例均以40~64岁年龄组病例占比最高,波动于38.54%~43.69%。结论2017—2022年每年报告斑疹伤寒病例数居前的省份均为云南、安徽、广东、广西、四川、湖北、湖南、河北、山东9省份(自治区),每年合计报告病例数占全国病例数均在85.00%以上,云南、湖北、安徽省每年报告病例数呈增加趋势。病例高度散发与局部高发并存。应动态开展疫情分析、风险评估及预警,加强重点地区、重点人群综合防控措施,进一步降低居民感染风险。

tcpA基因单核苷酸多态性对O139群霍乱弧菌产毒株环境适应性的影响

目的研究tcpA基因的核苷酸突变对O139群霍乱弧菌产毒株环境适应性的影响。方法使用生物信息学方法确定tcpA基因在O139产毒株中的变异,使用同源重组方法构建tcpA基因突变株,通过比较原型株和突变株的生物膜形成、菌毛形成以及在不同浓度的营养物质条件下的生长情况,研究两者的生长和差异。结果在不同pH值条件下,无论是单独生长还是在模拟人体胃肠道环境的竞争实验中,突变株1都表现出更强的生长能力。结论tcpA基因的核苷酸突变影响O139群霍乱弧菌产毒株酸碱耐受能力。

北京市凉水河丰台段救生装备配置情况调查

目的了解城市亲水空间救生装备配置现况,有针对性地提出改善性政策建议。方法于2023年4月,走访调查北京市凉水河丰台段游人分布、救生装备配置情况;并采用方便抽样方式对路过游人进行救生装备发现情况的问卷调查。采用χ^(2)检验、趋势χ^(2)检验分别进行单因素分析及等级资料分析。结果发现救生装备点位23处、溺水风险点位56处,其中溺水风险点位未被救生装备覆盖率为55.4%。救生装备齐全率仅为26.1%,固定方式可及率为100%,固定位置可及率为91.1%。问卷调查结果显示,发现率(>68%)较高的救生装备的设立方式共同要素是位于交通要道、步道附近和窄步道处。结论虽然北京市凉水河丰台段临河溺水风险点位的救生装备覆盖不足、配置单一,但可及性优良。城市亲水空间救生装备设置参数标准亟待填补。

1950-2021年中国斑疹伤寒流行特征分析

目的分析斑疹伤寒在我国的流行病学特征,探讨我国斑疹伤寒防控工作面临的问题及挑战和策略。方法资料来源于中国公共卫生科学数据中心传染病历史数据库和中国疾病预防控制信息系统传染病报告信息管理系统1950-2021年斑疹伤寒报告数据,采用描述性统计方法、Mann-Kendall检验和圆形分布法对斑疹伤寒的发病情况、死亡情况、病死率进行分析,研究我国斑疹伤寒流行的时间、空间、人群分布和诊断现状。结果1950-2021年,我国共报告斑疹伤寒发病数452965例,死亡数7339例,分别在20世纪50年代、60年代和80年代的14年中报告发病数均过万。20世纪90年代以来,斑疹伤寒发病数和发病率大幅降低,流行强度以散发为主,但安徽省、湖北省和湖南省报告发病数呈上升趋势。斑疹伤寒在全年均可发病,但可呈现一定的季节聚集性,我国斑疹伤寒的发病率高峰集中在夏、秋季,不同省份斑疹伤寒的月发病高峰从北方至南方逐渐向前推移。斑疹伤寒发病的男女性别比为1.01∶1(18529∶18366),近年来女性发病数逐渐超过男性;≤9岁人群发病数占比最大(18.9%),≥50岁人群发病数呈增加趋势;发病人群职业以农民为主,并呈逐年增加趋势,学生和散居儿童发病数占比也较大。斑疹伤寒病例从发病日期至诊断日期间隔时间的中位数为6 d,实验室确诊病例占比较低,检测方法为外斐反应为主。结论尽管我国斑疹伤寒流行态势整体好转,仍需警惕局部暴发的风险,其防控工作仍面临很多挑战,需加强斑疹伤寒病原体检测和监测能力建设。

噬菌体vB_KpnP_QH2的生物学特性和基因组分析

目的对从医院污水中分离筛选的特异裂解多重耐药肺炎克雷伯菌的噬菌体vB_KpnP_QH2(简称QH2)进行生物学特性和基因组信息分析。方法将从医院污水中获得噬菌体QH2用琼脂双层平板法分离纯化,测定QH2生物学特性,用电镜观察其形态大小;通过测序得到QH2全基因组信息并进行注释和分析。结果QH2属于Slopekvirinae亚科,Drulisvirus属,有尾噬菌体;QH2裂解宿主菌可形成有晕环的噬菌斑;QH2的最佳感染复数为0.00001;其感染潜伏期为5 min,爆发期为15 min,20 min后进入稳定期,裂解量为2.8×10^(9)pfu/cell。QH2基因组全长43083 bp,为双链DNA,GC含量53.88%;预测并注释52个开放阅读框,不包含tRNA结构、毒力因子和耐药基因;序列分析显示QH2的ORF12和ORF13编码裂解细菌相关蛋白。结论从医院污水中分离筛选的QH2能特异裂解多重耐药肺炎克雷伯菌,其生物学特性稳定、安全,为研究噬菌体与宿主间的相互作用及多重耐药细菌感染的治疗提供实验材料。