单细胞与空间转录组分析研究进展

单细胞的异质性在胚胎发育、神经系统发育、癌症病变等生物学过程中具有重要的研究意义。单细胞转录组测序利用测序技术解析细胞内转录本序列,为细胞异质性研究提供可靠、准确的研究手段及观测视野,为揭示生物发育规律、疾病发生发展机制等提供了重要的技术手段。该文围绕单细胞与空间组学分析,综述了近年来发展的各类单细胞转录组测序、单细胞多组学测序及空间转录组分析方法,分析了其优缺点。同时展望了单细胞与空间转录组分析领域的发展趋势,即开发低成本、全方位、高通量、高分辨的单细胞空间多组学分析方法以实现对单个细胞更为细致、全面及准确的描述和精准单细胞图谱构建。     

Physical and chemical effects of phosphorus-containing compounds on laminar premixed flame

Phosphorus-containing compounds are the promising halon alternatives for flame inhibitions. However, some literatures suggested that the phosphorus-related inhibitors may behave as the unfavorable ones that will increase the burning velocity under lean-burn conditions, and this indeed posed potential threats to the fire prevention and fighting. To seek deeper insights into the reaction process, a numerical investigation was actualized to study the phosphorus-related effects on methane-air flames. By replacing a phosphorus-related inhibitor with the corresponding decomposed molecules, the detailed promoting and inhibiting effects of combustion were separated from the general chemical effect. A comparative study was carried out to identify the interaction between the two effects under different combustion conditions. It is observed that the promoting effect becomes the dominant factor during the reaction process when the equivalence ratio is smaller than 0.60. In this lean-burn condition, the exothermic reactions were faster than the others within the reaction chains due to the reduction of radical recombination in hydrocarbon oxidation. The results are believed to be useful for the further application and improvement of flame inhibitors.     

新型1×4塑料光纤功率耦合器的研制

提出了一种新型的塑料光纤功率耦合器 ,该耦合器与传统的拉锥型和混合棒塑料光纤耦合器不同。理论分析了它的损耗特性。该耦合器基于塑料光纤本身的热特性 ,分别将塑料光纤进行拉锥和热缩构成耦合器的两端 ,结构简单 ,制作容易 ,实验结果表明其性能也可满足塑料光纤短距离通信网的要求     

关于夫兰克——赫兹实验的讨论

引言著名的F—H实验被大多数原子物理学教材选用,作为阐明原子能级存在的实验事实。而且均仿照Franck和Hertz当年在论文中的表述方法,以激发电位曲线峰位的间距作为汞原子的第一激发电位。当前国内多数院校的近代物理实验中也均是这样处理的。然而实验中各种物理因素的影响较大,比较精确地确定峰位是困难     

Measuring vibration by using fiber Bragg grating and demodulating it by blazed grating

A method of measuring vibration by using fiber Bragg grating (FBG) and demodulating the spectrum by blazed grating is introduced. The sensor system is made of a simple supported beam with a FBG adhered to its upper surface. A blazed grating is used to demodulate the changing spectrum that is got from the sensor system, and a line charge-coupled device (CCD) is used to accept the diffraction spectrum. Through analyzing the number of the CCD's pixels, we can get the amplitude of vibration and the change of the temperature. The experimental results show that the vibration amplitude of the exciter matches the detected signal under the stable frequency. The temperature shift and vibration signal are also successfully separated.     

反相高效液相色谱对DABTH—氨基酸的分离与鉴定

应用反相高效液相色谱(RP-HPLC)技术,采用等度洗脱。对20种标准DABTH-氨基酸进行了分离与鉴定,灵敏度达到pmol水平;并以溶菌酶为模式蛋白,经手工DABITC/PITC双偶联方法对其N端部分序列进行Edman降解,其降解产物DABTH-氨基酸用RP-HPLC技术进行了鉴定,蛋白质微量序列分析的灵敏度达到nmol水平.     

TiO2纳米管负载Ag、Au、Pt纳米粒子的微波合成与表征(英)

TiO₂ nanotubes were prepared under normal pressure at a temperature of 120 ℃. Ag, Au, Pt nanoparticles supported on TiO₂ nanotubes were prepared by microwave assisted heating polyol process. TEM images showed that microwave prepared Ag, Au, Pt nanoparticles supported on TiO₂ nanotubes were small and well dispersed on the surface of the TiO₂ nanotubes. UV-Vis absorption spectra showed that the absorbance of Ag/TiO₂ nanotubes and Au/TiO₂ nanotubes in the visible light range increased greatly compared to the single titania nanotubes.     

螺环倍半萜(±)-α-花柏烯-3-酮的全合成

通过萜品油烯 ( Terpinolene)与 2 ,4-二氧代戊酸甲酯的 de Mayo反应得到 [2 +2 ]光加成产物 ,经反aldol重排 ,再环合成具有螺 [5 ,5 ]十一烷结构的花柏烯基本碳架 ,进而对其官能团进行化学修饰 ,完成了螺环倍半萜 (± ) -α-花柏烯 -3 -酮的全合成 .     

二价钴、镍杂多酸盐异构体聚苯胺掺杂材料的合成及荧光性能研究

本文首次以钴、镍为取代元素的杂多酸盐异构体在有酸的情况下采用液相法与苯胺进行掺杂,并采用IR光谱,UV-vis,X-射线粉末衍射测试手段对其进行分析,并对产物的荧光性、导电性能进行了研究。     

小麦麸皮粗多糖的基本结构特征、流变特性及其对体外消化酶抑制初探

小麦麸皮是小麦加工过程中的主要副产物，具有很高的营养价值与多种生物活性，其中非淀粉多糖含量较高，是主要活性成分之一。本试验采用碱提醇沉法制备小麦麸皮阿拉伯木聚糖(Wheat bran arabinoxylan, WBAX),采用高效液相色谱、离子色谱、红外光谱、SEM、流变等技术与方法，系统研究了WBAX的基本结构特征、流变特性以及对消化酶抑制的效果。结果表明，WBAX以中性糖为主(83.4%),同时含有少量蛋白质(8.6%)和糖醛酸(0.9%),主要由阿拉伯糖(30.3%)和木糖(37.8%)组成；阿拉伯糖与木糖的摩尔比(A/X)为0.8,表明WBAX支化程度较高。WBAX表观黏度存在剪切稀化行为，且随温度增加而降低。WBAX的微观形貌主要为片状、球状和丝状。此外，与α-葡萄糖苷酶抑制实验相比，WBAX对α-淀粉酶抑制率相对较高，且随着多糖浓度增加，对α-淀粉酶抑制率有一定上升趋势。综上所述，从小麦麸皮提取获得WBAX主要为阿拉伯木聚糖，具有一定的抑制α-淀粉酶活性作用，相关结果可为WBAX的开发与应用提供理论依据。