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921.
液-液-液微萃取-高效液相色谱法测定人血浆中的局部麻醉剂 总被引:10,自引:0,他引:10
建立了液-液-液微萃取与高效液相色谱联用技术同时测定人血浆中3种局部麻醉剂利多卡因、布比卡因和丁卡因的方法。考察了萃取时间、料液pH值和搅拌速度的影响,取佳萃取条件为萃取溶剂为200μL苯,接受相为1.0μL 0.2 mol/L HC l,搅拌速度为250 r/m in,萃取时间为45 m in。在该条件下,获得了高的富集因子(大于305倍)。方法的线性范围为:利多卡因和布比卡因0.025~5 mg/L,丁卡因0.05~5 mg/L,相关系数大于0.996;检出限依次为0.005、0.015和0.025 mg/L;相对标准偏差小于5%。该方法能有效地去除血浆中复杂基体的干扰,萃取效率高,有机溶剂消耗少,是一种有效、灵敏的同时测定血浆中利多卡因、布比卡因和丁卡因的方法。 相似文献
922.
923.
Zhong‐Quan Zhang Jian‐Chao Chen Xian‐Ming Zhang Zhong‐Rong Li Ming‐Hua Qiu 《Helvetica chimica acta》2008,91(8):1494-1499
Two new spirostanol saponins, (1β,3β,5β,25S)‐spirostan‐1,3‐diol 1‐(β‐D ‐xylopyranoside) ( 1 ) and (1β,3β,5β,25S)‐spirostan‐1,3‐diol 1‐[α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐fucopyranoside] ( 2 ), along with two known compounds, (1β,3β,5β,25S)‐spirostan‐1,3‐diol 1‐[α‐L ‐rhamnopyranosyl‐(1→2)‐β‐D ‐xylopyranoside] ( 3 ) and (1β,3β,4β,5β,25S)‐spirostan‐1,3,4,5‐tetrol 5‐(β‐D ‐glucopyranoside) ( 4 ) were isolated from the whole plant of Reineckia carnea. The structures of the new steroids were determined by detailed analysis of their 1D‐ and 2D‐NMR spectra and chemical methods, and by comparison with spectral data of known compounds. Compounds 3 and 4 were isolated from the genus Reineckia for the first time. 相似文献
924.
Dong‐E Wang Feng Wang Xiang‐Gao Meng Yu Ding Li‐Li Wen Dr. Dong‐Feng Li Prof. Dr. She‐Ming Lan 《无机化学与普通化学杂志》2008,634(14):2643-2648
Three inorganic‐organic hybrid frameworks [Mn(HIMDC)(4,4′‐bipyo)0.5(H2O)]n (1) , [Cd(H2IMDC)2(2,2′‐bipyo)] (2) and [Ca(HIMDC)(H2O)2·H2O]n (3) (H3IMDC = 4,5‐imidazoledicarboxylate; 4,4′‐bipyo = 4,4′‐bipyridine‐N,N′‐dioxide; 2,2′‐bipyo= 2,2′‐bipyridine‐N,N′‐dioxide) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra, TG analysis and the single crystal diffraction. Both compounds 1 and 3 exhibit 2D layers while 2 is a monomer. It is noteworthy that compound 2 exhibits strong fluorescent emission in the solid state at room temperature. 相似文献
925.
Jiehao Du Banggui Cheng Huiqing Yuan Yuan Tao Ya Chen Mei Ming Zhiji Han Richard Eisenberg 《Angewandte Chemie (International ed. in English)》2023,62(9):e202211804
We report the unprecedented electrocatalytic activity of a series of molecular nickel thiolate complexes ( 1 – 5 ) in reducing CO2 to C1–3 hydrocarbons on carbon paper in pH-neutral aqueous solutions. Ni(mpo)2 ( 3 , mpo=2-mercaptopyridyl-N-oxide), Ni(pyS)3− ( 4 , pyS=2-mercaptopyridine), and Ni(mp)2− ( 5 , mp=2-mercaptophenolate) were found to generate C3 products from CO2 for the first time in molecular complex. Compound 5 exhibits Faradaic efficiencies (FEs) of 10.6 %, 7.2 %, 8.2 % for C1, C2, C3 hydrocarbons respectively at −1.0 V versus the reversible hydrogen electrode. Addition of CO to the system significantly promotes the FEC1–C3 to 41.1 %, suggesting that a key Ni−CO intermediate is associated with catalysis. A variety of spectroscopies have been performed to show that the structures of nickel complexes remain intact during CO2 reduction. 相似文献
926.
Dr. Xiaofei Yang Dr. Xuejie Gao Dr. Ming Jiang Dr. Jing Luo Jitong Yan Jiamin Fu Dr. Hui Duan Dr. Shangqian Zhao Prof. Yongfu Tang Dr. Rong Yang Ruying Li Prof. Jiantao Wang Dr. Huan Huang Prof. Chandra Veer Singh Prof. Xueliang Sun 《Angewandte Chemie (International ed. in English)》2023,62(5):e202215680
Sulfide electrolytes with high ionic conductivities are one of the most highly sought for all-solid-state lithium batteries (ASSLBs). However, the non-negligible electronic conductivities of sulfide electrolytes (≈10−8 S cm−1) lead to electron smooth transport through the sulfide electrolyte pellets, resulting in Li dendrite directly depositing at the grain boundaries (GBs) and serious self-discharge. Here, a grain-boundary electronic insulation (GBEI) strategy is proposed to block electron transport across the GBs, enabling Li−Li symmetric cells with 30 times longer cycling life and Li−LiCoO2 full cells with three times lower self-discharging rate than pristine sulfide electrolytes. The Li−LiCoO2 ASSLBs deliver high capacity retention of 80 % at 650 cycles and stable cycling performance for over 2600 cycles at 0.5 mA cm−2. The innovation of the GBEI strategy provides a new direction to pursue high-performance ASSLBs via tailoring the electronic conductivity. 相似文献
927.
Yandong Wu Wei Chen Yimin Jiang Yanzhi Xu Bo Zhou Leitao Xu Chao Xie Ming Yang Mengyi Qiu Dongdong Wang Qie Liu Prof. Qinghua Liu Prof. Shuangyin Wang Prof. Yuqin Zou 《Angewandte Chemie (International ed. in English)》2023,62(30):e202305491
Synthesis of cyclohexanone oxime via the cyclohexanone-hydroxylamine process is widespread in the caprolactam industry, which is an upstream industry for nylon-6 production. However, there are two shortcomings in this process, harsh reaction conditions and the potential danger posed by explosive hydroxylamine. In this study, we presented a direct electrosynthesis of cyclohexanone oxime using nitrogen oxides and cyclohexanone, which eliminated the usage of hydroxylamine and demonstrated a green production of caprolactam. With the Fe electrocatalysts, a production rate of 55.9 g h−1 gcat−1 can be achieved in a flow cell with almost 100 % yield of cyclohexanone oxime. The high efficiency was attributed to their ability of accumulating adsorbed hydroxylamine and cyclohexanone. This study provides a theoretical basis for electrocatalyst design for C−N coupling reactions and illuminates the tantalizing possibility to upgrade the caprolactam industry towards safety and sustainability. 相似文献
928.
Dr. Ying-Jie Sun Wen-Da Chen Dr. Ji Liu Jun-Jin Li Yu Zhang Wei-Qi Cai Prof. Li Liu Xin-Jing Tang Jian Hou Prof. Ming Wang Prof. Liang Cheng 《Angewandte Chemie (International ed. in English)》2023,62(5):e202212413
The CRISPR/Cas system is one of the most powerful tools for gene editing. However, approaches for precise control of genome editing and regulatory events are still desirable. Here, we report the spatiotemporal and efficient control of CRISPR/Cas9- and Cas12a-mediated editing with conformationally restricted guide RNAs (gRNAs). This approach relied on only two or three pre-installed photo-labile substituents followed by an intramolecular cyclization, representing a robust synthetic method in comparison to the heavily modified linear gRNAs that often require extensive screening and time-consuming optimization. This tactic could direct the precise cleavage of the genes encoding green fluorescent protein (GFP) and the vascular endothelial growth factor A (VEGFA) protein within a predefined cutting region without notable editing leakage in live cells. We also achieved light-mediated myostatin (MSTN) gene editing in embryos, wherein a new bow-knot-type gRNA was constructed with excellent OFF/ON switch efficiency. Overall, our work provides a significant new strategy in CRISPR/Cas editing with modified circular gRNAs to precisely manipulate where and when genes are edited. 相似文献
929.
Dr. Qingpei Liu Dan Zhang Shuaibiao Gao Xianhua Cai Dr. Ming Yao Yao Xu Yifu Gong Ke Zheng Yigui Mao Liyan Yang Dr. Dengfeng Yang Dr. István Molnár Dr. Xiaolong Yang 《Angewandte Chemie (International ed. in English)》2023,62(6):e202214379
Orsellinic acid (OA) derivatives are produced by filamentous fungi using nonreducing polyketide synthases (nrPKSs). The chain-releasing thioesterase (TE) domains of such nrPKSs were proposed to also catalyze dimerization to yield didepsides, such as lecanoric acid. Here, we use combinatorial domain exchanges, domain dissections and reconstitutions to reveal that the TE domain of the lecanoric acid synthase Preu6 of Preussia isomera must collaborate with the starter acyl transferase (SAT) domain from the same nrPKS. We show that artificial SAT-TE fusion proteins are highly effective catalysts and reprogram the ketide homologation chassis to form didepsides. We also demonstrate that dissected SAT and TE domains of Preu6 physically interact, and SAT and TE domains of OA-synthesizing nrPKSs may co-evolve. Our work highlights an unexpected domain–domain interaction in nrPKSs that must be considered for the combinatorial biosynthesis of unnatural didepsides, depsidones, and diphenyl ethers. 相似文献
930.