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A NKT cell repertoire is characterized by the expression of the Valpha19-Jalpha26 invariant TCR alpha chain (Valpha19 NKT cell). This repertoire, as well as a well-established Valpha14-Jalpha281 invariant TCR alpha(+) NKT cell subset (Valpha14 NKT cell), has been suggested to have important roles in the regulation of the immune system and, thus, is a major therapeutic target. Here, we attempted to find specific antigens for Valpha19 NKT cells. Valpha19 as well as Valpha14 NKT cells exhibited reactivity to alpha-galactosyl ceramide (alpha-GalCer). Thus, a series of monoglycosyl ceramides with an axially oriented glycosidic linkage between the sugar and ceramide moiety were synthesized and their antigenicity to Valpha19 NKT cells was determined by measuring their immune responses in culture with glycolipids. Comprehensive examinations revealed substantial antigenic activity for Valpha19 NKT cells by alpha-mannosyl ceramide. 相似文献
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氧还原反应(ORR)是能进行能量存储的核心电化学过程。由于它的动力学速率缓慢,因此亟需制备出高活性的电催化剂来促进这一反应的速率。二维共价有机框架材料(2D COFs)的π-π堆积结构可赋予骨架高导电率,并且一维有序的孔道有利于促进中间反应体传输。因此,其在可再生能源领域中具有良好的应用前景,并有望作为能量存储与转化的强大催化平台。本文通过向2D COFs中引入金属卟啉单元及硫醚单元成功制备了两个2D COFs (JUC-600和JUC-601)。通过多种表征手段证明,这两个2D COFs均具有AA堆积的sql拓扑结构。通过电化学测试表明,Co2+配位的JUC-601具有更正的ORR起始电势(0.825 V)和半波电势(0.7 V)、更高的活性表面积(7.8 mF/cm2),更低的Tafel斜率(58 mV/dec)。这主要是由于JUC-601的高比表面积和高孔隙率使得中间产物能更易在COFs的表面和孔道中接触和传输。此外,Co2+-卟啉单元以及硫醚单元的存在使其骨架整体的电子结构发生了变化,更有利于电子转移。这一工作不仅开发了新的二维卟啉-硫醚基COFs材料,同时也拓展了2D COFs材料在电催化领域的应用。 相似文献
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Near-infrared (NIR) persistent luminescent β-Ga2O3:Cr3+ nanowire assemblies were synthesized by a hydrothermal process followed by calcination. The phosphor exhibits more than 4 h afterglow in the wavelength range of 650-850 nm after ceasing the ultraviolet light (280-360 nm) irradiation. The trap structure and persistent luminescence mechanism were revealed by thermoluminescence measurement. The β-Ga2O3:Cr3+ nanowire assemblies may find applications as identification taggants in security and optical probes in bio-imaging. 相似文献
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Yi-Ying Lin Bao-Dong Song Xiang-Ming Wang Cong-Cong Zhang Xiao-Cong Zhang Shi-Wei Sun Song-Hai Wu Hai-Tao Ren Shao-Yi Jia Yong Liu Xu Han 《应用有机金属化学》2020,34(9):e5735
Pyrite catalyzes oxidation of various organic contaminants by dissolved oxygen (DO) under acidic conditions; however, the catalytic mechanism under alkaline conditions is still not clear. In this study, we observe increased oxidation rates of aniline with increasing pHs (7.0–11.0). Electron paramagnetic resonance (EPR) analysis and quenching experiments rule out contributions of •OH, O2•−, 1O2 and Fe (IV) to aniline oxidation and suggest that the Fe (III)–OOH peroxo and/or H2O2 are the primary oxidative species in the oxidation of aniline at pH 11.0. In addition, 200 mg L−1 H2O2 does not apparently increase the oxidation rate of aniline, which also rules out the predominant contribution of the produced H2O2 to aniline oxidation. We therefore suggest that the Fe (III)–OOH peroxo is indeed the primary oxidative species in the pyrite–DO system under alkaline conditions. Analyses of solid total organic carbon (TOC), gas chromatography–mass spectrometry and Fourier-transform infrared spectroscopy further reveal that more than 83.3% aniline has been polymerized to polyaniline, instead of being mineralized into CO2 and H2O, indicating that H-abstraction from aniline by the Fe (III)–OOH peroxo is an important step in the oxidation of aniline under alkaline conditions. This study provides new insight into the oxidative species in the pyrite–DO system, and opens a new door for organic degradations under alkaline conditions. 相似文献
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On the (N+1)-dimensional local fractional reduced differential transform method and its applications
Jian-Gen Liu Xiao-Jun Yang Yi-Ying Feng Ping Cui 《Mathematical Methods in the Applied Sciences》2020,43(15):8856-8866
In this paper, we generalize the (N+1)-dimensional local fractional reduced differential transform method (LFRDTM) within the local fractional derivative sense. First, we show some new properties, lemmas, theorems and corollariesfor the (N+1)-dimensional LFRDTM. Second, these new properties, lemmas and theorems can be proved immediately after. Thirdly, we used two examples to state that this approach is efficient and simple to find numerical solutions to higher dimensional local fractional partial differential equations. Finally, we can be seen that this work can be looked as an extension of the prior work. 相似文献
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We investigate the pairwise thermal quantum discord in a three-qubit XXZ model with Dzyaloshinskii-Moriya (DM) interaction. We find that the effects of DM interaction on antiferromagnetic system is distinct from that of ferromagnetic system. The magnetic field supplemented with DM term contribute to enhance the range of quantum discord. It is revealed that the situations where quantum discord fails to indicate a sudden change of groundstate at finite temperature though indicating such a sudden change of groundstate at zero temperature. Dynamics of pairwise thermal quantum discord is considered as well. Thermal quantum discord vanishes in asymptotic limit regardless of its initial values, however, thermal entanglement suddenly disappears in finite time. 相似文献
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采用化学气相沉积方法,在无催化剂的条件下,通过改变衬底位置在Si(100)衬底上制备出了高取向的磷掺杂ZnO纳米线和纳米钉.测试结果表明,当衬底位于反应源上方1.5 cm处时,所制备的样品为钉状结构,而当衬底位于反应源下方1 cm处时样品为线状结构.对不同形貌磷掺杂ZnO纳米结构的生长机理进行了研究.此外,在ZnO纳米结构的低温光致发光谱中观测到了一系列与磷掺杂相关的受主发光峰.还对磷掺杂ZnO纳米结构/n-Si异质结I-V曲线进行了测试,结果表明,该器件具有良好的整流特性,纳米线和纳米钉异质结器件的开启电压分别为4.8和3.2 V. 相似文献
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