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951.
Jung-Ah Kang Ji-Sun Kwak Sang-Heon Park Kyu-Young Sim Seul Ki Kim Youngnim Shin In Jung Jung Jeong-In Yang Jang-Soo Chun Sung-Gyoo Park 《Experimental & molecular medicine》2021,53(4):560
Zinc is a trace element that is essential for immune responses. Therefore, changes in cellular zinc levels in specific immune cells may influence inflammatory autoimmune diseases, such as rheumatoid arthritis (RA). However, the regulation of zinc mobilization in immune cells and its role in the pathogenesis of RA are not fully understood. Thus, we investigated the roles of zinc transporters in RA pathogenesis. We demonstrated that ZIP8 was specifically upregulated in CD4+ T cells that infiltrated the inflamed joint and that ZIP8 deficiency in CD4+ T cells abrogated collagen-induced arthritis. ZIP8 deficiency dramatically affected zinc influx in effector T cells and profoundly reduced T cell receptor (TCR)-mediated signaling, including NF-κB and MAPK signaling, which are pathways that are involved in T helper (Th) 17 cell differentiation. Taken together, our findings suggest that ZIP8 depletion in CD4+ T cells attenuates TCR signaling due to insufficient cellular zinc, thereby reducing the function of effector CD4+ T cells, including Th17 cells. Our results also suggest that targeting ZIP8 may be a useful strategy to inhibit RA development and pathogenesis.Subject terms: Autoimmunity, Immunological disorders 相似文献
952.
The biological effects of aluminium have received much attention in recent years. Speciation of Al is of basic relevance as it concerns its reactivity and bioavailability. A differential pulse voltammetry (DPV) procedure is proposed for speciation analysis of Al(III) in natural waters and biological fluids using six catechols (L-dopa, dopamine, epinephrine, norepinephrine, caffeic acid and o-benzenediol) as electroactive ligands. The decrease of the DPV anodic peak current for each catechol ligand is linear with the increase of Al concentration. This speciation analysis idea is based on the measurement of the complexation capacity, namely, different affinities of Al(III) for catechols and organic ligands under two pH conditions. The labile monomeric Al fraction (mainly inorganic aluminium) is determined at pH 4.6, while the total monomeric Al fraction is determined at pH 8.5. The principle for Al(III) speciation analysis by an electrochemical method is discussed. This sensitive and simple fractionation method is successfully applied to the speciation analysis of Al in natural waters and the results agree well with those of Driscoll's method. The speciation analysis of Al in biological fluids is also explored and the results are compared with those obtained by ultrafiltration and dialysis. Compared with other speciation protocols the electrochemical method possesses some remarkable advantages: rapidity, high sensitivity, cheap instrumentation and a simple operation procedure. 相似文献
953.
气相色谱法测定三聚氰氯的研究李秀梅赵树岚*田锦霞*孙维星(东北师范大学化学系长春130024)关键词气相色谱法三聚氰氯三聚氰氯(CNCl)3是活性染料的重要中间体及合成树脂、橡胶、塑料等的防老剂,也常用于除草剂、增白剂、药物、炸药等的生产中。传统的分... 相似文献
954.
A Tosflex-mercury film electrode (TMFE) was prepared by spin-coating a solution of the perfluorinated anion exchange polymer Tosflex onto a glassy carbon electrode surface followed by electrodeposition of mercury film on this electrode. This electrode was used for the determination of trace bismuth(III) which was preconcentrated onto the TMFE as anionic bismuth(III) complexes with chloride in a chloride medium. The preconcentration was carried out at a potential of-0.2 V, and the preconcentration of the bismuth(III) was enhanced significantly by the anion-exchange feature of Tosflex. The accumulated bismuth(III) was then determined by anodic square-wave stripping voltammetry (SWSV). Various parameters influencing the determination of bismuth(III) were examined in detail. With 2 min accumulation, the analytical signal versus concentration dependence was linear up to 50 ppb, and the detection limit was 0.58 ppb. This modified electrode showed good resistance to the interferences from surface-active compounds and common ions. 相似文献
955.
Alan R. Katritzky Scott A. Henderson Baozhen Yang 《Journal of heterocyclic chemistry》1998,35(5):1123-1159
Applications of benzotriazole methodology for the preparation of heterocyclic compounds are reviewed. The characteristic advantages of benzotriazole as a synthetic auxiliary are first briefly considered. This is followed by a summary of its use in ring synthesis in which the construction of small; five-membered; six-membered; and larger heterocyclic rings using benzotriazole methodology are each examined separately. Finally, consideration of the use of benzotriazole in the ring annulation - particularly benzannulation - of heterocycles. Subsequent sections deal with the introduction of substituents into aromatic heterocycles; the ring substitution of saturated heterocycles; and benzotriazole assisted modification of heterocyclic substituents. The present review supplements a recent comprehensive review of benzotriazole chemistry [1] which covers the literature through 1996. 相似文献
956.
A polarographic investigation of the copper-3-hydroxy-1-p-sulphonatophenyl-3-phenyltriazene (HSPT) complex in 0.05 M sodium tetraborate medium is described and a simple and sensitive single-sweep polarographic method for the determination of trace amounts of copper in biological samples is proposed. The complex was shown to be Cu(HSPT)2 with log beta' = 11.38. The polarographic wave is caused by the reduction of copper(II) in the adsorbed complex to copper amalgam on the surface of a mercury electrode. The current peak is directly proportional to the concentration of copper in the range 8.0 x 10(-9)-4.0 x 10(-6) M and the detection limit is 5.0 x 10(-9) M. 相似文献
957.
本文研究了丙烯酸酯共聚物载体对驱蚊剂N,N-二乙基间甲苯酰胺(DETA)慢释放行为的控制,探讨了单体配比、共聚物分子量以及DETA含量对释放速率的影响。结果表明。增加亲水性单体丙烯酸(AA),可提高DETA的释放速率;降低共聚物数均分子量,会减少DETA的释放量;剂型中DETA含量与释放量存在线性正比关系,但DETA的含量增加并不导致释放有效时间的线性增加。本文还就共聚物膜的透湿性和碱溶性作了研究,亲水性单体AA的增加同样导致透湿性和碱溶性的增加。制备的聚合物驱蚊剂经现场应用试验,表明具有良好的长效驱蚊特性。 相似文献
958.
959.
960.
The hydrothermal reaction of NaVO(3).H(2)O, barbituric acid, NH(2)NH(2).2HCl, H(3)PO(4), and H(2)O gave a novel heteropolyoxovanadate Na(6)[(P(V)O(4))V(V)(6)V(IV)(12)O(39)](2).H(3)PO(4).31H(2)O (1) and an unexpected phase Na(2)[C(12)H(6)N(6)O(9)].7H(2)O (2). The basic building blocks in 1 are the six-capped sphere-shaped heteropoly anion [(P(V)O(4))V(V)(6)V(IV)(12)O(39)](3-) with framework similar to that of the reported polyoxovanadates possessing [V(18)O(42)] clusters encapsulating VO(4) or other ions. These heterpoly anionic units are linked via V[bond]O[bond]V bridges into an interesting 3D straight-channel structure. The structure of 2 consists of novel organic anions ([C(12)H(6)N(6)O(9)](2-), 5,5-bis(2',4',6'-trioxopyrimidyl)barbital, representing the first oxidized barbituric acid trimer) linked via sodium ions into 1D hollow tubes with diameter of 4.49 x 6.86 A and further connected into a three-dimensional framework via hydrogen bonds. 相似文献