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排序方式: 共有571条查询结果,搜索用时 15 毫秒
1.
Dr. Jun Zeng Dr. Zhichao Wang Dr. Xin Huang Dr. Sabine S. Eckstein Prof. Dr. Xiaohui Lin Prof. Dr. Hailong Piao Prof. Dr. Cora Weigert Dr. Peiyuan Yin Prof. Dr. Rainer Lehmann Prof. Dr. Guowang Xu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(21):5427-5432
Mass spectrometry (MS) driven metabolomics is a frequently used tool in various areas of life sciences; however, the analysis of polar metabolites is less commonly included. In general, metabolomic analyses lead to the detection of the total amount of all covered metabolites. This is currently a major limitation with respect to metabolites showing high turnover rates, but no changes in their concentration. Such metabolites and pathways could be crucial metabolic nodes (e.g., potential drug targets in cancer metabolism). A stable-isotope tracing capillary electrophoresis–mass spectrometry (CE-MS) metabolomic approach was developed to cover both polar metabolites and isotopologues in a non-targeted way. An in-house developed software enables high throughput processing of complex multidimensional data. The practicability is demonstrated analyzing [U-13C]-glucose exposed prostate cancer and non-cancer cells. This CE-MS-driven analytical strategy complements polar metabolite profiles through isotopologue labeling patterns, thereby improving not only the metabolomic coverage, but also the understanding of metabolism. 相似文献
2.
Deposition of Hydrogen-Free Silicon Nitride Thin Films by Microwave ECR plasma Enhanced Magnetron Sputtering at Room Temperature 下载免费PDF全文
Hydrogen-free silicon nitride (SiNx) films were deposited at room temperature by microwave electron cyclotron resonance (MW-ECR) plasma enhanced unbalance magnetron sputtering system. Both Fourier-transform infrared spectroscopy and x-ray photoelectron spectroscopy are used to study the bonding type and the change of bonding structures of the silicon nitride films. The results indicate that the chemical structure and composition of SiNx films deposited by this technique depend strongly on the N2 flow rates, the stoichiometric SiNx film, which has the highest hardness of 22.9 GPa, could be obtained at lower N2 flow rate of 4 sccm. 相似文献
3.
In a recent work (Int. J. Solids Struct. 37 (2000) 1561) by one of the authors, an extended system for calculating critical points of equilibrium paths in imperfect structures was presented. However, the extremum nature of these points was not analyzed explicitly in that paper. In this note, we will fill in the gap and establish a sufficient condition for determining the buckling strength of imperfect structures. 相似文献
4.
硅杂环丁烷在有机硅化学中是一类非常重要的小分子环系化合物。由于硅杂环丁烷和环丁烷的环张力相似,因而显示出较高的反应活性。例如能与某些试剂作用,生成开环产物;在光解或热解条件下,产生具有Si=C结构的高活性中间体,可用以合成多种有机硅化合物。 相似文献
5.
Flow injection spectrofluorimetry with in-line Winklers procedure was developed for the dissolved oxygen (DO) determination. 2-Thionaphthol reacted with iodine produced by Winkler’s method to form fluorescence inactive disulfide compound. To automate the process completely, a 5-channel flow system with a newly designed 16-way valve was assembled. The system consisted of a dispersion coil (DC), a precipitate formation coil (PFC), a precipitate dissolving coil (PDC), and extraction coil (EC). A calibration can be constructed by using a standard iodine solution for dissolved oxygen. The calibration graph was linear over the range 1.2×10−4∼6.0×10−4 mol l−1 iodine (1.96∼9.80 mg O l−1)). The relative standard deviation (n=6) was below 0.3% for the 4×10−4 mol l−1 iodine (6.27 mg O l−1) determination. The sample throughput was 12/h. 相似文献
6.
Photocatalytic oxidation of water is a promising method to realize large-scale H2O2 production without a hazardous and energy-intensive process. In this study, we introduce a Pt/TiO2(anatase) photocatalyst to construct a simple and environmentally friendly system to achieve simultaneous H2 and H2O2 production. Both H2 and H2O2 are high-value chemicals, and their separation is automatic. Even without the assistance of a sacrificial agent, the system can reach an efficiency of 7410 and 5096 μmol g–1 h–1 (first 1 h) for H2 and H2O2, respectively, which is much higher than that of a commercial Pt/TiO2(anatase) system that has a similar morphology. This exceptional activity is attributed to the more favorable two-electron oxidation of water to H2O2, compared with the four-electron oxidation of water to O2. 相似文献
7.
Byeong Hyo Kim Rongbi HanFengyu Piao Young Moo JunWoonphil Baik Byung Min Lee 《Tetrahedron letters》2003,44(1):77-79
N-Arylacetamides were prepared in excellent yields from nitroarenes in the presence of acetic anhydride, acetic acid and indium by a one-pot procedure. 相似文献
8.
9.
Zhuang Guisun Wang Yinson Tan Mingguang Zhi Min Wang Yongjie Zhang Fulin 《Journal of Radioanalytical and Nuclear Chemistry》1991,151(2):327-335
Elemental profiles of brain tumor tissues from 15 patients of astrocytomas (grade I–III) and normal human brain tissues of 23 male age matched autopsies as controls have been studied by instrumental neutron activation analysis. The SLOWPOKE reactor with a thermal neutron flux of 8·1011n·cm–2·s–1 and swimming pool type reactor with a thermal neutron flux of 1·1013n·cm–2·s–1 were used for short and long irradiation of samples, respectively. Spectrophotometry was only used for analyzing phosphorus. A total of 18 elements Se, Na, K, Br, Cl, Mn, Mg, S, Ca, Cu, Hg, Cr, Fe, Rb, Zn, Co, Sc and P has been determined for this purpose. The reliability of methods has been checked by analyzing biological standard reference materials horse kidney (IAEA H-8) and bovine liver (NBS SRM 1577a). The analytical results showed that compared with the normal brain tissues, concentrations of Ca, Fe, Cu, Zn, Se, Mn, Br and Sc were significantly higher in tumor tissues (P<0.01) and concentrations of Rb, K and P were lower, while no differences for contents of Mg, S, Cr, Hg, Na and Cl were observed. A negative correlation between P and Ca in malignant and normal brain tissues was observed. 相似文献
10.
XPS定量分析及其在CdTe(Ⅲ)面识别化学物种中的应用 总被引:3,自引:0,他引:3
我们用谱仪能量传输函数修正的相对原子灵敏度因子获得了XPS定量数据。通过将定量结果与结合能的化学位移相结合的方法,分析了CdTe表面的两个氧化过程,结果表明,机械抛光样品表面的构成是:66%CdTe,28.9%的Cd(OH)2和5.1%TeOx(X>2),而经化学抛光的表面构成是∶84.4%的TdTeO4和15.6%TeOx(X>1)。 相似文献