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排序方式: 共有6125条查询结果,搜索用时 31 毫秒
921.
A series of novel amide derivatives bearing an indazole moiety were synthesized and evaluated for their in vitro S-adenosyl-L-homocysteine hydrolase (SAHase) inhibitory activity. Among these compounds, 8b, 8m, 8r and 8w showed better or similar inhibitory effects compared to the positive control aristeromycin. These results provide a novel lead for the discovery of more potent non-adenosine analogs as SAHase inhibitors. 相似文献
922.
923.
目的通过多中心随机对照的临床试验研究,比较以胶原蛋白为基质的新型肠内营养制剂与标准型肠内营养制剂对患者营养状况的影响,以了解新型肠内营养制剂的临床应用效果。方法本研究共6家医疗单位共同参与,共收集91例,分为对照组(标准肠内营养)及干预组(以胶原蛋白为基质的肠内营养),管饲补充104.6~125.5kJ(25~30kcal)/(kg·d),共7d,检测研究开始前后患者体格指标、营养相关指标、安全性指标等。结果组内比较显示两组患者在管饲两种不同的肠内营养制剂后营养风险筛查评分(NRS2002)较管饲前均有所降低(均P<0.025);组间差值比较显示患者营养状况、营养风险筛查(NRS2002)评分、胃肠道不良反应在两组间均无统计学差异(均P>0.025)。结论以胶原蛋白为基础经氨基酸模式优化后的肠内营养制剂与标准型肠内营养制剂均可以有效改善患者的营养状况,有助于促进患者的疾病预后。 相似文献
924.
A Copper‐Catalyzed Decarboxylative Amination/Hydroamination Sequence: Switchable Synthesis of Functionalized Indoles
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Tian‐Ren Li Bei‐Yi Cheng Ya‐Ni Wang Mao‐Mao Zhang Prof. Dr. Liang‐Qiu Lu Prof. Dr. Wen‐Jing Xiao 《Angewandte Chemie (International ed. in English)》2016,55(40):12422-12426
A copper‐catalyzed decarboxylative amination/hydroamination sequence of propargylic carbamates with various nucleophiles is described for the first time. It features an earth‐abundant metal catalyst, mild reaction conditions, and high efficiency. Further treatments of the resultant key intermediates using an acid or a base in one pot enable the controllable and divergent synthesis of two types of functionalized indoles. Moreover, experiments to demonstrate the synthetic potential of this methodology are performed. 相似文献
925.
Use of an Octapeptide–Guanidiniocarbonylpyrrole Conjugate for the Formation of a Supramolecular β‐Helix that Self‐Assembles into pH‐Responsive Fibers
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Mao Li Marijana Radić Stojković Martin Ehlers Elio Zellermann Prof. Ivo Piantanida Prof. Carsten Schmuck 《Angewandte Chemie (International ed. in English)》2016,55(42):13015-13018
Peptides that adopt β‐helix structures are predominantly found in transmembrane protein domains or in the lipid bilayer of vesicles. Constructing a β‐helix structure in pure water has been considered difficult without the addition of membrane mimics. Herein, we report such an example; peptide 1 self‐assembles into a supramolecular β‐helix in pure water based on charge interactions between the individual peptides. Peptide 1 further showed intriguing transitions from small particles to helical fibers in a time‐dependent process. The fibers can be switched to vesicles by changing the pH value. 相似文献
926.
Back Cover: Hydrogels from Amorphous Calcium Carbonate and Polyacrylic Acid: Bio‐Inspired Materials for “Mineral Plastics” (Angew. Chem. Int. Ed. 39/2016)
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927.
Polystyrene Sulfonate Threaded through a Metal–Organic Framework Membrane for Fast and Selective Lithium‐Ion Separation
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Dr. Yi Guo Dr. Yulong Ying Dr. Yiyin Mao Prof. Xinsheng Peng Prof. Banglin Chen 《Angewandte Chemie (International ed. in English)》2016,55(48):15120-15124
Extraction of lithium ions from salt‐lake brines is very important to produce lithium compounds. Herein, we report a new approach to construct polystyrene sulfonate (PSS) threaded HKUST‐1 metal–organic framework (MOF) membranes through an in situ confinement conversion process. The resulting membrane PSS@HKUST‐1‐6.7, with unique anchored three‐dimensional sulfonate networks, shows a very high Li+ conductivity of 5.53×10?4 S cm?1 at 25 °C, 1.89×10?3 S cm?1 at 70 °C, and Li+ flux of 6.75 mol m?2 h?1, which are five orders higher than that of the pristine HKUST‐1 membrane. Attributed to the different size sieving effects and the affinity differences of the Li+, Na+, K+, and Mg2+ ions to the sulfonate groups, the PSS@HKUST‐1‐6.7 membrane exhibits ideal selectivities of 78, 99, and 10296 for Li+/Na+, Li+/K+, Li+/Mg2+ and real binary ion selectivities of 35, 67, and 1815, respectively, the highest ever reported among ionic conductors and Li+ extraction membranes. 相似文献
928.
Xiaochen Cui Meijie Yu Chengguo Wang Fazhan Li Qiong Mao 《Polymer Science Series A》2016,58(3):357-367
The effects of electrospinning parameters in a wider range on the morphology and diameters of polyacrylonitrile (PAN) fibers are studied in detail. The fibers’ diameter increases from 288 to 3469 nm swiftly with the increasing PAN concentration. With the increasing voltage or prolonging gap distance, the diameter increases primarily and decreases later. The combined effects of surface tension, splitting and stretching, electric force, viscosity, and solvent volatilization are the main reasons. Ultrasonic etching method, Atomic force microscope (AFM), Scanning electron microscope (SEM) and X-ray diffraction (XRD) technology have been utilized to verify the nature structure of electrospun PAN fibers. Combining all the results, it is deduced that there are many grooves arranging nearly perpendicular to the fiber axis on the surface of electrospun PAN fibers. The thickness of relative ordered region is 40 to 190 nm and the thickness of amorphous region is 20 to 35 nm. 相似文献
929.
Chang Sun Zhiyong Huang Jiaxin Wang Liming Rao Jingjing Zhang Jiao Yu Jinmei Du Changhai Xu 《Cellulose (London, England)》2016,23(5):2917-2927
Microcrystalline cellulose (MCC) was modified with pyridone derivatives such as pyridone diester (PDE) and pyridone diacid (PDA) by using succinic acid anhydride as a linker. The modified MCCs were characterized by the fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis, elemental analysis and solid state 13C NMR. The adsorption capacities of the modified MCCs to cationic dyes were examined by using methylene blue (MB) as a model dye. It was found that the kinetic adsorption data followed the pseudo-second-order kinetic model, and the adsorption equilibriums were reached less than 10 min. The isothermal adsorption data were fitted with the Langmuir isotherm model very well, from which the maximum adsorption capacities of the MCCs modified with PDE and PDA were determined to be 101.01 and 142.86 mg/g, respectively. Further investigation showed that the modified MCCs were pH-dependent for adsorption of MB in aqueous solutions. The modified MCCs could be used for removal of MB from an aqueous solution at pH 8, and reused by regeneration in an acidic solution. It was tested that the modified MCCs had a high reusability for removal of MB from aqueous solutions, and still maintained high adsorption capacities even after multiple cycles of desorption–adsorption processes. Hence, the MCCs modified with PDE and PDA could be an effective and efficient approach to removal of cationic dyes from aqueous solutions. 相似文献
930.
Electrochemical C−H/N−H Functionalization for the Synthesis of Highly Functionalized (Aza)indoles
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Zhong‐Wei Hou Zhong‐Yi Mao Huai‐Bo Zhao Yared Yohannes Melcamu Prof. Dr. Xin Lu Dr. Jinshuai Song Prof. Dr. Hai‐Chao Xu 《Angewandte Chemie (International ed. in English)》2016,55(32):9168-9172
Indoles and azaindoles are among the most important heterocycles because of their prevalence in nature and their broad utility in pharmaceutical industry. Reported herein is an unprecedented noble‐metal‐ and oxidant‐free electrochemical method for the coupling of (hetero)arylamines with tethered alkynes to synthesize highly functionalized indoles, as well as the more challenging azaindoles. 相似文献