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151.
Zhang B Li JF Zhong QL Ren B Tian ZQ Zou SZ 《Langmuir : the ACS journal of surfaces and colloids》2005,21(16):7449-7455
Core-shell Au-Pt nanoparticles were synthesized by using a seed growth method and characterized by transmission electron microscopy, X-ray diffraction, and UV-vis spectroscopy. Au(core)-Pt(shell)/GC electrodes were prepared by drop-coating the nanoparticles on clean glassy carbon (GC) surfaces, and their electrochemical behavior in 0.5 M H2SO4 revealed that coating of the Au core by the Pt shell is complete. The electrooxidation of carbon monoxide and methanol on the Au(core)-Pt(shell)/GC was also examined, and the results are similar to those obtained on a bulk Pt electrode. High quality surface-enhanced Raman scattering (SERS) spectra of both adsorbed CO and thiocyanate were observed on the Au(core)-Pt(shell)/GC electrodes. The potential-dependent SERS features resemble those obtained on electrochemically roughened bulk Pt or Pt thin films deposited on roughened Au electrodes. For thiocyanate, the C-N stretching frequency increases with the applied potential, yielding two distinctly different dnu(CN)/dE. From -0.8 to -0.2 V, the dnu(CN)/dE is ca. 50 cm(-1)/V, whereas it is 90 cm(-1)/V above 0 V. The bandwidth along with the band intensity increases sharply above 0 V. At the low-frequency region, Pt-NCS stretching mode at 350 cm(-1) was observed at the potentials from -0.8 to 0 V, whereas the Pt-SCN mode at 280 cm(-1) was largely absent until around 0 V and became dominant at more positive potentials. These potential-dependent spectral transitions were attributed to the adsorption orientation switch from N-bound dominant at the negative potential region to S-bound at more positive potentials. The origin of the SERS activity of the particles is briefly discussed. The study demonstrates a new method of obtaining high quality SERS on Pt-group transition metals, with the possibility of tuning SERS activity by varying the core size and the shell thickness. 相似文献
152.
The interactions between proteins and Ponceau 4R (PR) in aqueous solution have been studied by the techniques of resonance light scattering (RLS) spectroscopy, the absorption spectroscopy, zeta potential assay and circular dichroism (CD) spectrum. The dry PR can assemble on the surface of protein via electrostatic and hydrophobic forces to produce an associated compound of protein-PR, this compound can enhance the RLS of protein. Based on this fact, a simple, rapid, and sensitive method has been developed for the determination of proteins at nanogram level by RLS technique with a common spectrofluorimeter. Under optimum conditions, the linear range is 0.10-39.2 μg mL−1 for the determination of both bovine serum albumin (BSA) and human serum albumin (HSA). The detection limits (S/N = 3) are 6.96 ng mL−1 for BSA and 5.71 ng mL−1 for HSA, respectively. There is almost no interference from amino acids, most of the metal ions, and other coexistent substances. The method has been satisfactorily applied to the direct determination of the total protein in human serum. 相似文献
153.
An electrochemical synthesis of oxazol‐2‐ones and imidazol‐2‐ones has been developed via 5‐exo‐dig cyclization of propargylic carbamates‐ and ureas‐derived amidyl radicals. The electrosynthesis relies on the dual function of 2,2,6,6‐tetramethylpiperidin‐ 1‐yl)oxyl (TEMPO) as a redox mediator for amidyl radical formation and an oxygen atom donor. The reactions are conducted under mild conditions using a simple setup and provide convenient access to functionalized oxazol‐2‐ones and imidazol‐2‐ones from readily available materials. 相似文献
154.
A new program to characterize polyethylene glycol-modified (PEGylated) proteins is outlined using capillary zone electrophoresis (CZE). PEGylated ribonuclease A and lysozyme were selected as examples. Five separation procedures were compared to select out the mixed buffer of acetonitrile-water (1:1, v/v) at pH 2.5 as the best to characterize the PEGylated proteins without sample pretreatment. Polyethylene oxide (PEO) with a high molecular mass of 8 x 10(6) was applied to rinse the capillary to form a dynamic coating which would decrease the undesirable proteins adsorbed to the inner wall of the silica. The electroosmotic flow (EOF) mobility of the five procedures was determined, respectively. It is found that acetonitrile is mainly responsible for the good resolution of PEGylated proteins with the help of PEO coating in the semi-aqueous system. The low EOF mobility and current in the semi-aqueous system might also have some responsibility for the high resolution. The semi-aqueous procedure described in this paper also demonstrates higher resolution of natural proteins than aqueous ones. 相似文献
155.
Crystal orientation-ordered ZnS nanowire bundles 总被引:1,自引:0,他引:1
We report a novel approach for growing aligned and orientation-ordered ZnS nanowires. Our method relies on a buffer layer of CdSe grown on a Si(111) substrate, on which ZnS nanowires are grown. The growth process of the nanowire bundles is presented. The technique demonstrated could be an effective pathway for growing patterned, aligned, size-controlled, and orientation-ordered ZnS nanowires. 相似文献
156.
Photo-controlled reversible-deactivation radical polymerization(photo-RDRP) has been investigated as a "green" and spatiotemporally controlling pathway for polymer synthesis. While the combination of photo-RDRP and flow chemistry has offered opportunities to increase light intensity and enable uniform light irradiation, problems associated with flow approaches still remain for photoflow-RDRP, which has hindered merging flow polymerization with other cutting-edge techniques. Herein, we summarize ... 相似文献
157.
158.
二氧化碳(CO2)是一种丰富、廉价、无毒以及可再生的一碳资源,也是一种可用于聚合的绿色单体.基于CO2的聚合是近年来的研究热点之一.目前广泛报道的是CO2和环氧单体的聚合反应,经过几十年的发展已经成功实现工业化生产.最近几年,一些CO2参与的新型聚合反应被陆续报道,这些工作大都通过两种途径实现从CO2到高分子材料的转变.第一个途径是先将CO2转化为可以聚合的单体,例如:内酯、环状碳酸酯和2,5-二呋喃甲酸等,再利用开环或者逐步聚合将单体转化为聚合物;另一个途径是直接以CO2为单体和其他类型单体共聚得到聚合物.这两种途径对于发展CO2参与的新型聚合反应,拓展CO2基聚合物种类都具有重要意义.本综述按照CO2直接还是间接参与聚合反应分类总结了近年来在CO2制备高分子材料方面的进展,并对未来发展方向进行了简单阐述. 相似文献
159.
160.
Hui-Hui Yang Hui-Ling Jiang Jia-Hao Tao Chen-Yu Zhang Jian-Bing Xiong Jin-Tong Yang Yu-Biao Liu Wen-Jing Zhong Xin-Xin Guan Jia-Xi Duan Yan-Feng Zhang Shao-Kun Liu Jian-Xin Jiang Yong Zhou Cha-Xiang Guan 《Experimental & molecular medicine》2022,54(11):2077
Necroptosis is the major cause of death in alveolar epithelial cells (AECs) during acute lung injury (ALI). Here, we report a previously unrecognized mechanism for necroptosis. We found an accumulation of mitochondrial citrate (citratemt) in lipopolysaccharide (LPS)-treated AECs because of the downregulation of Idh3α and citrate carrier (CIC, also known as Slc25a1). shRNA- or inhibitor–mediated inhibition of Idh3α and Slc25a1 induced citratemt accumulation and necroptosis in vitro. Mice with AEC-specific Idh3α and Slc25a1 deficiency exhibited exacerbated lung injury and AEC necroptosis. Interestingly, the overexpression of Idh3α and Slc25a1 decreased citratemt levels and rescued AECs from necroptosis. Mechanistically, citratemt accumulation induced mitochondrial fission and excessive mitophagy in AECs. Furthermore, citratemt directly interacted with FUN14 domain-containing protein 1 (FUNDC1) and promoted the interaction of FUNDC1 with dynamin-related protein 1 (DRP1), leading to excessive mitophagy-mediated necroptosis and thereby initiating and promoting ALI. Importantly, necroptosis induced by citratemt accumulation was inhibited in FUNDC1-knockout AECs. We show that citratemt accumulation is a novel target for protection against ALI involving necroptosis.Subject terms: Infection, Respiratory tract diseases 相似文献