喀什边境口岸陆运卡车及集装箱污染的新冠病毒基因特征分析

新疆维吾尔自治区喀什地区作为我国与中亚和欧洲的重要陆路货运口岸,来往货物运输频繁,引入新型冠状病毒(SARS-CoV-2)风险大,对我国新型冠状病毒肺炎(COVID-19)疫情防控造成压力.2020年11月我国新疆维吾尔自治区喀什地区发生输入SARS-CoV-2导致的本土聚集性COVID-19疫情.为明确货物运输载体携带SARS-CoV-2的基因特征以及边境快速物流系统作为SARS-CoV-2传播载体的可能性,本研究对2020年11月6日-2020年11月10日期间在喀什边境口岸货运卡车及运输的集装箱采集的35份SARS-CoV-2核酸阳性样本进行SARS-CoV-2全基因组序列测定和比对分析.结果 显示,35份样本ORFlab基因Ct值的中位数(最小值～最大值)为37.64(28.91～39.81),N基因Ct值的中位数(最小值～最大值)为36.50(26.35～39.30),Reads数匹配率的中位数(最小值～最大值)为51.95％(0.86％～99.31％),病毒载量较低;35份样本中基因组覆盖度达到70％以上的共计18份.基于Pango命名法,18条SARS-CoV-2基因组序列分别属于B.1、B.1.1、B.1.9、B.1.1.220、B.1.153和B.1.465共6个不同的基因型,其中3个基因型(B.1、B.1.1和B.1.153)在喀什边境接壤或邻近的四个国家同期采集的病例样本中也有发现.核苷酸突变位点和系统进化树分析显示,同一个地点采集的样本病毒基因组相似程度高;18条序列中的4条与喀什COVID-19疫情毒株代表序列处在同一个进化分支;其中1条序列与喀什COVID-19疫情毒株基因组存在1个或2个核苷酸突变位点差异,高度同源.本研究证实喀什COVID-19疫情期间边境货运卡车和集装箱存在境外多种基因型病毒的污染,其中存在喀什COVID-19疫情毒株的祖父代病毒,高度提示边境快速物流系统卡车及集装箱作为载体携带SARS-CoV-2病毒入境造成了本土疫情,这些数据为我国边境口岸地区的新冠防控策略制定及后续疫情溯源提供了关键的参考依据.     

小麦倒春寒研究现状与进展

由于全球气候变暖,近年来小麦低温灾害事件频发,尤其是拔节-孕穗期的倒春寒灾害已成为制约小麦产量和品质的重要因素之一。本文综述了小麦倒春寒灾害的发生特点(鉴定与分级、时空特征),倒春寒对小麦生理特性(叶片、茎秆、穗部、根系)和产量、质量的影响,总结了抗倒春寒小麦育种、倒春寒危害的分子生物学机制及灾害的监测预警与风险评估等方面的研究进展,并从小麦抗倒春寒遗传基础、倒春寒危害小麦评价体系和防控技术体系等方面进行了展望,以期为抗倒春寒小麦品种的遗传改良和栽培调控新措施的建立提供理论依据。     

4种河鲀全基因组微卫星分布特征分析

本研究利用MISA软件对四种河鲀全基因组中的微卫星进行筛选并分析.结果如下:在红鳍东方鲀(Takifugu rubripes)(391.49 Mb)、菊黄东方鲀(T.flavidus)(366.29 Mb)、双斑东方鲀(T.bimaculatus)(371.68 Mb)及黑青斑河鲀(Tetraodon nigroviridis)(342.40 Mb)全基因组中,分别筛选出142 885个、135 009个、147 549个和179 703个完整型微卫星.相对丰度分别为365个/Mb,369个/Mb,397个/Mb和525个/Mb.微卫星总长度分别为2 876 322 bp,2 689 710 bp,3 140 445 bp 和3 615 069 bp,分别占基因组序列总长度的0.73％,0.73％,0.84％和1.06％.在1～6个不同碱基重复类型完整型微卫星中,四种河鲀的6种碱基类型数目排序是一致的.均是单碱基重复数目最多,然后依次是二碱基、三碱基、四碱基、五碱基和六碱基.其中AC,A,C,AG,AGG,AT,AAT和AAC是四种河鲀共有的常见核心重复类别.东方鲀属(Takifugu)三种河鲀基因组微卫星分布特征极为相似,分析红鳍东方鲀和双斑东方鲀的遗传距离可能更为接近.鲀属(Tetraodon)黑青斑河鲀与其他三种东方鲀属河鲀除部分微卫星特征相似外,在微卫星总数、微卫星相对丰度和密度、部分碱基类型数目及类别方面和东方鲀属差距较大.这可能与两属鱼类地理分布及进行滑动复制的碱基组成有关,推测东方鲀属和鲀属基因组可能具有独特的进化机制.本研究为多种河鲀基因组特征分析、多种河鲀微卫星引物设计、不同属种河鲀遗传距离及亲缘关系的探究等奠定了基础.     

黄色肉芽肿性胆囊炎与胆囊癌的临床特征分析及螺旋CT检查的鉴别诊断价值

目的:研究黄色肉芽肿性胆囊炎(XGC)与胆囊癌的临床特征分析及螺旋CT检查的鉴别诊断价值。方法:选取从2018年1月-2020年12月于我院接受腹部螺旋CT检查的41例XGC患者纳入研究,记作XGC组,另取同期医院接受腹部螺旋CT检查的45例胆囊癌患者作为胆囊癌组。分析两组临床特征、螺旋CT检查结果表现,比较两组血清血管内皮生长因子(VEGF)、糖类抗原19-9(CA19-9)水平的差异。并以病理检查为金标准,分析螺旋CT检查用作XGC与胆囊癌鉴别诊断的价值。结果:XGC组患者食欲下降、体重下降人数占比均低于胆囊癌组(均P<0.05);而两组腹痛、黄疸、发热、白细胞(WBC)升高、谷丙转氨酶(ALT)升高、谷草转氨酶(AST)升高、胆囊扩张发生率对比差异无统计学意义(均P>0.05)。XGC组囊壁增厚均匀、壁内有低密度结节人数占比均低于胆囊癌组,而有肿大淋巴结人数占比高于胆囊癌组(均P<0.05)。螺旋CT检查诊断XGC的灵敏度、特异度、准确度分别为95.12(39/41)、95.56%(43/45)、95.35%(82/86)。XGC组患者血清VEGF、CA19-9水平均低于胆囊癌组,差异均有统计学意义(均P<0.05)。结论:XGC患者食欲下降、体重下降发生率低于胆囊癌患者,螺旋CT检查鉴别诊断XGC与胆囊癌的价值较高,值得临床关注。     

Smoking increases oral mucosa susceptibility to Candida albicans infection via the Nrf2 pathway: In vitro and animal studies

Smoking and Candida albicans (C. albicans) infection are risk factors for many oral diseases. Several studies have reported a close relationship between smoking and the occurrence of C. albicans infection. However, the exact underlying mechanism of this relationship remains unclear. We established a rat infection model and a C. albicans-Leuk1 epithelial cell co-culture model with and without smoke exposure to investigate the mechanism by which smoking contributes to C. albicans infection. Oral mucosa samples from healthy individuals and patients with oral leucoplakia were also analysed according to their smoking status. Our results indicated that smoking induced oxidative stress and redox dysfunction in the oral mucosa. Smoking-induced Nrf2 negatively regulated the NLRP3 inflammasome, impaired the oral mucosal defence response and increased the oral mucosa susceptibility to C. albicans. The results suggest that the Nrf2 pathway could be involved in the pathogenesis of oral diseases by mediating an antioxidative response to cigarette smoke exposure and suppressing host immunity against C. albicans.     

Design of Sub wavelength-Grating-Coupled Fano Resonance Sensor in Mid-infrared

Plasmonics - By introducing the sub-wavelength grating (SWG) waveguide in the long-range surface phonon resonance (LRSPhR) device, a mid-infrared Fano resonance is formed due to the coupling...     

Dynamically Tunable Plasmon-induced Transparency in a T-shaped Cavity Waveguide Based on Bulk Dirac Semimetals

We propose a dynamically tunable surface plasmon polaritons (SPPs) waveguide system based on bulk Dirac semimetals (BDS) containing only a side-coupled T-shaped cavity. Plasmon-induced transparency (PIT) is achieved in the terahertz band by introducing a position offset. We have analytically investigated the spectral characteristics of PIT in this system, indicating that the larger the position offset, the higher the peak of the PIT window. The spectrum responses of PIT system can be flexibly regulated via transforming the geometric parameters of the structure. At the same time, it is particularly sensitive to the refractive index of the surrounding medium, which is promising for sensing devices. In addition, the resonance frequency and peak transmission can be actively adjusted by controlling the Fermi energy of the BDS without reconstructing the geometric structure. Moreover, the optical delay time near the PIT peak reaches 11.001 ps, which has good slow-light characteristics and is a candidate in the field of slow-light equipment. The structure we designed may have potential application value in the design of SPPs light-guide devices.