SnS2 Nanosheets as a Template for 2D SnO2 Sensitive Material: Nanostructure and Surface Composition Effects

Two-dimensional nanosheets of semiconductor metal oxides are considered as promising for use in gas sensors, because of the combination of a large surface-area, high thermal stability and high sensitivity, due to the chemisorption mechanism of gas detection. In this work, 2D SnO₂ nanosheets were synthesized via the oxidation of template SnS₂ nanosheets obtained by surfactant-assisted one-pot solution synthesis. The 2D SnO₂ was characterized using transmission and scanning electron microscopy (TEM, SEM), X-ray diffraction (XRD), low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and IR spectroscopy. The sensor characteristics were studied when detecting model gases CO and NH₃ in dry (RH₂₅ = 0%) and humid (RH₂₅ = 30%) air. The combination of high specific-surface-area and increased surface acidity caused by the presence of residual sulfate anions provides a high 2D SnO₂ sensor’s signal towards NH₃ at a low temperature of 200 °C in dry air, but at the same time causes an inversion of the sensor response when detecting NH₃ in a humid atmosphere. To reveal the processes responsible for sensor-response inversion, the interaction of 2D SnO₂ with ammonia was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) in dry and humid air at temperatures corresponding to the maximum “positive” and maximum “negative” sensor response.     

不同压力呼气末正压对单肺通气时肺内分流及氧合的影响

目的观察单肺通气(OLV)期间通气侧肺实施不同大小的呼气末正压通气(PEEP)对肺内分流及氧合的影响。方法45例ASAⅠ～Ⅱ级择期在全麻下行肺叶切除手术病人,随机分为3组,每组15例。A组为不采用PEEP的OLV对照组;B组为OLV PEEP(5cmH2O)组;C组为OLV PEEP(8cmH2O)组。各组病例于OLV前、OLV后30min、OVL结束、恢复双肺通气后30min进行动脉血气分析,根据公式计算肺内分流率(QS/QT)。结果OVL30min及OVL结束时,B、C两组的PaO2较A组高,QS/QT较A组低(P<0.05);B、C两组各时点参数比较差异无统计学意义(P>0.05)。结论OVL期间通气侧肺实施5cmH2O及8cmH2O的PEEP可明显提高PaO2,减少肺内分流;5cmH2O的PEEP有利于手术操作,临床实用价值更高。     

顶空气相色谱法检测他达拉非原料药中4种溶剂残留量

目的建立测定他达拉非原料药中4种常见溶剂(甲醇、乙腈、异丙醇、四氢呋喃)残留量的顶空气相色谱法。方法采用顶空进样方式,分离柱采用DB-624柱(30 m×0.53 mm,3.0μm),程序升温,进样口温度为230℃,分流比为5∶1,载气为高纯氮气(纯度为99.999%),载气流速为1.8 mL/min;采用氢火焰离子化检测器检测,检测器温度为250℃。外标法定量。结果甲醇、乙腈、异丙醇、四氢呋喃的质量浓度线性范围分别为0.66~1.5 mg/mL,0.0082~0.205 mg/mL,0.06~1.5 mg/mL,0.0144~0.36 mg/mL;平均加样回收率分别为101.22%,100.59%,97.74%,100.73%,RSD分别为4.67%,2.63%,1.01%,2.28%(n=6);检测限分别为2μg/mL,8μg/mL,5μg/mL,6μg/mL。结论该方法操作简单,灵敏度高,准确性好,为可他达拉非中有机溶剂残留量的控制提供依据。     

Forecasting the Post-Pandemic Effects of the SARS-CoV-2 Virus Using the Bullwhip Phenomenon Alongside Use of Nanosensors for Disease Containment and Cure

The COVID-19 pandemic has the tendency to affect various organizational paradigm alterations, which civilization hasyet to fully comprehend. Personal to professional, individual to corporate, and across most industries, the spectrum of transformations is vast. Economically, the globe has never been more intertwined, and it has never been subjected to such widespread disruption. While many people have felt and acknowledged the pandemic’s short-term repercussions, the resultant paradigm alterations will certainly have long-term consequences with an unknown range and severity. This review paper aims at acknowledging various approaches for the prevention, detection, and diagnosis of the SARS-CoV-2 virus using nanomaterials as a base material. A nanostructure is a material classification based on dimensionality, in proportion to the characteristic diameter and surface area. Nanoparticles, quantum dots, nanowires (NW), carbon nanotubes (CNT), thin films, and nanocomposites are some examples of various dimensions, each acting as a single unit, in terms of transport capacities. Top-down and bottom-up techniques are used to fabricate nanomaterials. The large surface-to-volume ratio of nanomaterials allows one to create extremely sensitive charge or field sensors (electrical sensors, chemical sensors, explosives detection, optical sensors, and gas sensing applications). Nanowires have potential applications in information and communication technologies, low-energy lightning, and medical sensors. Carbon nanotubes have the best environmental stability, electrical characteristics, and surface-to-volume ratio of any nanomaterial, making them ideal for bio-sensing applications. Traditional commercially available techniques have focused on clinical manifestations, as well as molecular and serological detection equipment that can identify the SARS-CoV-2 virus. Scientists are expressing a lot of interest in developing a portable and easy-to-use COVID-19 detection tool. Several unique methodologies and approaches are being investigated as feasible advanced systems capable of meeting the demands. This review article attempts to emphasize the pandemic’s aftereffects, utilising the notion of the bullwhip phenomenon’s short-term and long-term effects, and it specifies the use of nanomaterials and nanosensors for detection, prevention, diagnosis, and therapy in connection to the SARS-CoV-2.     

Transport Property and Spin–Orbit Torque in 2D Rashba Ferromagnetic Electron Gas

In this paper, we investigate the spin–orbit torque and transport property in a 2D Rashba ferromagnetic electron gas. The longitudinal conductivity can be divided into two parts: the first term is determined by the charge density and is independent of the spin degrees of freedom. The second term depends on the two bands that spin in the opposite directions, and it is directly proportional to spin–orbit torque regardless of the band structure and temperature. This is a general and underlying relation between the transport property and spin–orbit torque. Moreover, we show the impacts of the spin–orbit coupling constant and Fermi energy on transverse conductivity and spin–orbit torque, which is helpful for relevant experiments.     

气相色谱-质谱联用分析青风藤挥发油中化学成分

目的：方法：用药典记载的提取方法提取药材青风藤的挥发油，经过气相色谱-质谱联用分析，共分离出200多个峰，通过与软件中的质谱标准谱图库比较鉴定出其中101种化合物。结果：青风藤中主要物质为n-十六烷酸和（Z，Z）-9，12-十八烷酸。意义：该研究为青风藤的物质基础研究和进一步的开发应用提供实验依据。     

黄芪、三七和西洋参中多种有机氯农药残留量分析

目的 :测定黄芪、三七和西洋参中15种有机氯农药残留量。方法 :样品经混合溶剂超声提取、Florisil硅土柱层析净化后 ,采用毛细管气相色谱 电子捕获检测器分析被测农药。结果和结论 :2水平的平均加标回收率在 77.30 %～130.1% ,RSD为0.75 %～31.9%。各被测样品中均含有机氯农药残存。     

色谱指纹图谱技术和化学计量学方法分析药对生姜-白术挥发油成分

目的对由生姜、白术及其药对中提取的挥发油组分进行检测。方法采用的方法是气相色谱-质谱指纹图谱技术(GC-MS)和交互移动窗口因子法(AMWFA)。定性分析的方法是质谱库和程序升温保留指数结合,而定量分析是采取总体积积分法。结果生姜、白术和药对生姜-白术的挥发油分别定性59、40和45个成分,占总含量的91.48%、93.52%和89.73%,药对生姜-白术与生姜、白术的共有组分分别为25和12个。结论药对挥发油的组分并不是两种单味药的简单加和。     

益气养阴方治疗糖尿病周围神经病变的临床研究

目的：观察益气养阴方治疗糖尿病周围神经病变（DPN）的临床疗效。方法：将8r）例DPN患者随机分为治疗组（46例）和对照组（36例）,观察两组疗效。结果：治疗组总有效率为86．7％,显效率为57．8％;对照组总有效率为46．7％,显效率为13．3％,两组间有统计学差异（P〈0．01）;治疗组在血流变方面优于对照组（P〈0.05）。结论：益气养阴方治疗糖尿病周围神经病变疗效确切,值得推广。     

双鱼颗粒挥发性成分指纹图谱和定量分析

目的建立双鱼颗粒挥发性成分指纹图谱及定量测定方法。方法 Agilent DB-1毛细管柱(30 m×0.32 mm,0.25μm);进样量为1μL;分流比为25∶1;进样口温度为230℃;以氮气为载气,体积流量0.6 mL/min;FID检测器温度为250℃;程序升温。结果建立的指纹图谱分离度和重复性良好,确定12个共有峰,各批次样品相似度在0.95以上;采用GC/MS对色谱峰进行定性分析,其中7个成分经对照品比对,分别为桉油精(峰2)、樟脑(峰3)、薄荷酮(峰4)、龙脑(峰5)、薄荷脑(峰6)、(+)-胡薄荷酮(峰9)、甲基正壬酮(峰10),其中1、10、11、12号峰主要来自于鱼腥草,2、5号峰主要来自于艾叶和薄荷,3号峰主要来自于艾叶,4、6、8、9号峰主要来自于薄荷,7号峰主要来自于艾叶、薄荷和鱼腥草。并对其中桉油精、薄荷脑进行定量分析,平均回收率分别为103.9%和98.2%,RSD分别为2.1%和2.3%。10批次样品中桉油精为0.17～0.23mg/g,薄荷脑为0.45～0.67mg/g。结论建立的双鱼颗粒指纹图谱和2个指标成分定量分析方法,快速、简便、准确,能有效评价该制剂的质量。