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971.
Five isostructural tetranuclear lanthanide complexes with the general formula [Ln4(teaH2)2(teaH)2(NO3)6] · 2CH3OH [Ln3+ = Dy3+ ( 1 ), Tb3+ ( 2 ), Ho3+ ( 3 ), Er3+ ( 4 ), and Gd3+ ( 5 )] were successfully synthesized by the reaction of various lanthanide nitrate and triethanolamine (teaH3) ligand. Single crystal X-ray analyses reveal the eight-coordinate Ln3+ centers adopt a slightly distorted triangular dodecahedron geometry and nine-coordinate Ln3+ ions own an approximately capped square antiprism environment in similar zigzag Ln4 core. Magnetic studies demonstrate the presence of anitferromagnetic interactions between Ln3+ centers without obvious SMM behavior. 相似文献
972.
We report amperometric determination of sugars by using a disposable barrel plating nickel electrode (Ni‐BPE) in this study. The activated Ni‐BPE possesses good reproducibility in flow injection analysis of sugars with a relative standard deviation of 3.16% for 10 consecutive injections of glucose. The electrocatalytic mechanism for the detection of sugars as well as the use as a detector in high‐performance liquid chromatography (HPLC) is investigated. We achieve a good separation of four sugars (glucose, fructose, sucrose, and maltose) in HPLC with favorable sensitivity at a detection potential of +0.55 V vs. Ag/AgCl. The results of wide linear calibration ranges and detection limits in the μM range meet the need of real sample analysis. This detection method is successfully used for quantitative determination of sugars in honey to identify its authentication. 相似文献
973.
Chi‐Ming Che Prof. Hai‐Feng Xiang Dr. Stephen Sin‐Yin Chui Dr. Zong‐Xiang Xu V. A. L. Roy Dr. Jessie Jing Yan Wen‐Fu Fu Prof. P. T. Lai Prof. Ian D. Williams Prof. 《化学:亚洲杂志》2008,3(7):1092-1103
Organic field‐effect transistors incorporating planar π‐conjugated metal‐free macrocycles and their metal derivatives are fabricated by vacuum deposition. The crystal structures of [H2(OX)] (H2OX=etioporphyrin‐I), [Cu(OX)], [Pt(OX)], and [Pt(TBP)] (H2TBP=tetra‐(n‐butyl)porphyrin) as determined by single crystal X‐ray diffraction (XRD), reveal the absence of occluded solvent molecules. The field‐effect transistors (FETs) made from thin films of all these metal‐free macrocycles and their metal derivatives show a p‐type semiconductor behavior with a charge mobility (μ) ranging from 10?6 to 10?1 cm2 V?1 s?1. Annealing the as‐deposited Pt(OX) film leads to the formation of a polycrystalline film that exhibits excellent overall charge transport properties with a charge mobility of up to 3.2×10?1 cm2 V?1 s?1, which is the best value reported for a metalloporphyrin. Compared with their metal derivatives, the field‐effect transistors made from thin films of metal‐free macrocycles (except tetra‐(n‐propyl)porphycene) have significantly lower μ values (3.0×10?6–3.7×10?5 cm2 V?1 s?1). 相似文献
974.
Ya‐Ching Shen Yu‐Chi Lin Yuan‐Bin Cheng Chia‐Ju Chang Ting‐Wei Lan Shorong‐Shii Liou Ching‐Te Chien Chia‐Ching Liaw Ashraf Taha Khalil 《Helvetica chimica acta》2008,91(3):483-494
Seven new oxygenated lignans, kadsuphilins G–M ( 1 – 7 , resp.), were isolated by chromatographic fractionation of an AcOEt extract of the aerial part of Kadsura philippinensis including four compounds with a dibenzocyclooctadiene skeleton, two with a bicyclooctane ring system, and one of 1,4‐biphenyldimethylbutane type. The structures of the isolated compounds were elucidated through extensive spectroscopic analyses, particularly 2D‐NMR experiments (HMQC, HMBC, and NOESY). The configuration of the chiral centers and the biphenyl moiety were determined by NOESY as well as CD spectroscopy, respectively. 相似文献
975.
Siyu Chi Li Zhang Hemei Cheng Yaran Chang Dr. Yaoyao Zhao Prof. Xiayan Wang Prof. Zhihong Liu 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304419
Glioma features high fatality rate and short survival time of patients due to its fast growth speed and high invasiveness, hence timely treatment of early-stage glioma is extremely important. However, the blood brain barrier (BBB) severely prevents therapeutic agents from entering the brain; meanwhile, the non-targeted distribution of agents always causes side effects to vulnerable cerebral tissues. Therefore, delivery systems that possess both BBB penetrability and precise glioma targeting ability are keenly desired. We herein proposed a hybrid cell membrane (HM) camouflage strategy to construct therapeutic nanocomposites, in which HM consisting of brain metastatic breast cancer cell membrane and glioma cell membrane was prepared with a simple membrane fusion pathway. By coating HM onto drug-loaded nanoparticles, the as-obtained biomimetic therapeutic agent (termed HMGINPs) inherited satisfying BBB penetrability and homologous glioma targeting ability simultaneously from the two source cells. HMGINPs exhibited good biocompatibility and superior therapeutic efficacy towards early-stage glioma. 相似文献
976.
Prof. Weijie Chi Dr. Davin Tan Prof. Qinglong Qiao Prof. Zhaochao Xu Prof. Xiaogang Liu 《Angewandte Chemie (International ed. in English)》2023,62(39):e202306061
Single-molecule localization microscopy (SMLM) has found extensive applications in various fields of biology and chemistry. As a vital component of SMLM, fluorophores play an essential role in obtaining super-resolution fluorescence images. Recent research on spontaneously blinking fluorophores has greatly simplified the experimental setups and extended the imaging duration of SMLM. To support this crucial development, this review provides a comprehensive overview of the development of spontaneously blinking rhodamines from 2014 to 2023, as well as the key mechanistic aspects of intramolecular spirocyclization reactions. We hope that by offering insightful design guidelines, this review will contribute to accelerating the advancement of super-resolution imaging technologies. 相似文献
977.
Yao Xu Hai-Xiang Gao Chengkai Pan Yue Shi Dr. Chi Zhang Prof. Dr. Genping Huang Prof. Dr. Chao Feng 《Angewandte Chemie (International ed. in English)》2023,62(44):e202310671
By resorting to the principle of remote activation, we herein demonstrate the first photoredox catalyzed (3+3) dipolar cycloaddition of nitrones with aryl cyclopropanes. Key to the fidelity of the reaction resides in a facile manner of substrate activation by single-electron transfer (SET) oxidation with photoredox catalysis, and the reaction takes place through a stepwise cascade encompassing a three-electron-type nucleophilic substitution triggered cyclopropane ring-opening and a diastereoselective 6-endo-trig radical cyclization manifold. The reaction proceeds under mild conditions with excellent regio- and stereoselectivity, nicely complementing the well-developed Lewis acid catalyzed cycloaddition of donor-acceptor cyclopropanes. Other merits of the protocol include wide scope of aryl cyclopropanes with diversified substitution patterns and good functional-group compatibility. A mechanism involving an aryl radical cation promoted remote activation mode was also proposed and supported by mechanistic experiments. 相似文献
978.
Dr. Fengqin Li Junru Li Weiqiang Yang Dr. Shuai Yang Congshuo Chen Ling Du Junyang Mei Dr. Qianyun Tang Xiaojing Chen Dr. Chi Yao Prof. Dayong Yang Prof. Xiaolei Zuo Prof. Peifeng Liu 《Angewandte Chemie (International ed. in English)》2023,62(32):e202305536
The trans-cleavage property of CRISPR-Cas12a system makes it an excellent tool for disease diagnosis. Nevertheless, most methods based on CRISPR-Cas system still require pre-amplification of the target to achieve the desired detection sensitivity. Here we generate Framework-Hotspot reporters (FHRs) with different local densities to investigate their effect on trans-cleavage activity of Cas12a. We find that the cleavage efficiency increases and the cleavage rate accelerates with increasing reporter density. We further construct a modular sensing platform with CRISPR-Cas12a-based target recognition and FHR-based signal transduction. Encouragingly, this modular platform enables sensitive (100 fM) and rapid (<15 min) detection of pathogen nucleic acids without pre-amplification, as well as detection of tumor protein markers in clinical samples. The design provides a facile strategy for enhanced trans cleavage of Cas12a, which accelerates and broadens its applications in biosensing. 相似文献
979.
Dr. Jie Yu Prof. Shasha He Dr. Chi Zhang Cheng Xu Dr. Jingsheng Huang Mengke Xu Prof. Kanyi Pu 《Angewandte Chemie (International ed. in English)》2023,62(32):e202307272
The efficacy of combination immunotherapy has been limited by tumor specificity and immune-related adverse events (irAEs). Herein, we report the development of polymeric STING pro-agonists (PSPA), whose sono-immunotherapeutic efficacy is activated by sono-irradiation and elevated glutathione (GSH) within the tumor microenvironment (TME). PSPA is composed of sonosensitizers (semiconducting polymer) and STING agonists (MSA-2) via the GSH-activatable linkers. Under sono-irradiation, PSPA serves as a sonosensitizer to generate 1O2 and induce immunogenic cell death (ICD) of malignant tumor cells. Furthermore, MSA-2 is released specifically in tumor microenvironment with highly expressed GSH, minimizing off-target side effects. The activation of the STING pathway elevates the interferon-β level and synergizes with SDT to enhance the anti-tumor response. Therefore, this work proposes a universal approach for spatiotemporal regulation of cancer sono-immunotherapy. 相似文献
980.
Mengke Xu Jie Yu Chi Zhang Cheng Xu Dr. Xin Wei Prof. Kanyi Pu 《Angewandte Chemie (International ed. in English)》2023,62(40):e202308362
Cytokine therapy mediates the interaction between immune cells and non-immune cells in the tumor microenvironment (TME), forming a promising approach in cancer therapy. However, the dose-dependent adverse effects and non-selective stimulation of cytokines limit their clinical use. We herein report a sonodynamic cytokine nano-immunocomplex (SPNAI) that specifically activates effector T cells (Teffs) for antitumor immunotherapy. By conjugating anti-interleukin-2 (anti-IL-2) antibodies S4B6 on the semiconducting polymer nanoparticles to afford SPNA, this nanoantibody SPNA can bind with IL-2 to form SPNAI which can block the interaction between IL-2 and regulatory T cells (Tregs), selectively activating Teffs in TME. Moreover, SPNAI generates 1O2 to trigger immunogenic cell death of cancer cells upon sono-irradiation, which promotes the maturation of dendritic cells and the proliferation of Teffs. This SPNAI-mediated combination sonodynamic immunotherapy thus elevates the ratio of Teffs/Tregs in TME, resulting in inhibition of tumor growth, suppression of lung metastasis and prevention of tumor relapse. 相似文献