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961.
Dr. Cristian Pezzato Dr. Minh T. Nguyen Dr. Dong Jun Kim Dr. Ommid Anamimoghadam Dr. Lorenzo Mosca Prof. Dr. J. Fraser Stoddart 《Angewandte Chemie (International ed. in English)》2018,57(30):9325-9329
Artificial molecular machines can be operated using either physical or chemical inputs. Light‐powered motors display clean and autonomous operations, whereas chemically driven machines generate waste products and are intermittent in their motions. Herein, we show that controlled changes in applied electrochemical potentials can drive the operation of artificial molecular pumps in a semi‐autonomous manner—that is, without the need for consecutive additions of chemical fuel(s). The electroanalytical approach described in this Communication promotes the assembly of cyclobis(paraquat‐p‐phenylene) rings along a positively charged oligomeric chain, providing easy access to the formation of multiple mechanical bonds by means of a controlled supply of electricity. 相似文献
962.
Dr. Gerrit Jürjens Dr. Sören M. M. Schuler Dr. Michael Kurz Dr. Sylvain Petit Dr. Cédric Couturier Dr. Frédéric Jeannot Fabian Nguyen Dr. Raffael C. Wende Prof. Dr. Peter E. Hammann Prof. Dr. Daniel N. Wilson Dr. Eric Bacqué Dr. Christoph Pöverlein Dr. Armin Bauer 《Angewandte Chemie (International ed. in English)》2018,57(37):12157-12161
The total synthesis of the naturally occurring antibiotic GE81112A, a densely functionalized tetrapeptide, is reported. Comparison of spectral data with those of the natural product and the lack of biological activity of the synthesized compound led us to revise the published configuration of the 3‐hydroxypipecolic acid moiety. This hypothesis was fully validated by the synthesis of the corresponding epimer. 相似文献
963.
Glycosyl‐Substituted Dicarboxylates as Detergents for the Extraction,Overstabilization, and Crystallization of Membrane Proteins 下载免费PDF全文
Dr. Kim‐Anh Nguyen Dr. Marine Peuchmaur Sandrine Magnard Dr. Romain Haudecoeur Dr. Cédric Boyère Saravanan Mounien Ikram Benammar Veronica Zampieri Dr. Sébastien Igonet Dr. Vincent Chaptal Dr. Anass Jawhari Prof. Ahcène Boumendjel Dr. Pierre Falson 《Angewandte Chemie (International ed. in English)》2018,57(11):2948-2952
To tackle the problems associated with membrane protein (MP) instability in detergent solutions, we designed a series of glycosyl‐substituted dicarboxylate detergents (DCODs) in which we optimized the polar head to clamp the membrane domain by including, on one side, two carboxyl groups that form salt bridges with basic residues abundant at the membrane–cytoplasm interface of MPs and, on the other side, a sugar to form hydrogen bonds. Upon extraction, the DCODs 8 b , 8 c , and 9 b preserved the ATPase function of BmrA, an ATP‐binding cassette pump, much more efficiently than reference or recently designed detergents. The DCODs 8 a , 8 b , 8 f , 9 a , and 9 b induced thermal shifts of 20 to 29 °C for BmrA and of 13 to 21 °C for the native version of the G‐protein‐coupled adenosine receptor A2AR. Compounds 8 f and 8 g improved the diffraction resolution of BmrA crystals from 6 to 4 Å. DCODs are therefore considered to be promising and powerful tools for the structural biology of MPs. 相似文献
964.
One three-dimensional Sr(II) coordination polymer [C6(MIm)2][Sr3(1,4-NDC)4] (I) (C6(MIm)2 = 1,3-bis(3-methylimidazolium-1-yl)hexyl, 1,4-H2NDC = 1,4-naphthalenedicarboxylate acid) has been synthesized using an ionothermal method and structurally characterized by IR spectroscopy, UV-Vis spectroscopy, XRPD, and X-ray single-crystal structure analysis (СIF file CCDC 1033958). Two types of strontium centers are bridged by two coordination modes of 1,4-H2NDC ligands to form a Sr(II) chain. Each Sr(II) chain is crossconnected to four other chains to generate a 3D coordination polymer, in which C6(MIm) 2 2+ cations as charge balancing species are filled in the channels of the anionic framework. The polymeric solid of I exhibits strong luminescent emission at room temperature. 相似文献
965.
Huynh Le Thanh Nguyen Tran Thi Thuy Dung Nguyen Hoang Hai Au Nguyen Thi Thu Trang Tran Van Man Grag Akhil Le My Loan Phung 《Journal of Solid State Electrochemistry》2018,22(7):2247-2254
Journal of Solid State Electrochemistry - Olivine LiFePO4 (LFP) is a promising cathode material for high-rated lithium-ion batteries. However, olivine faced a severe disadvantage of low... 相似文献
966.
Nguyen Van Ho 《Applications of Mathematics》1998,43(2):93-102
Let X
i, 1 i N, be N independent random variables (i.r.v.) with distribution functions (d.f.) F
i(x,), 1 i N, respectively, where is a real parameter. Assume furthermore that F
i(·,0) = F(·) for 1 i N.
Let R = (R
1,R
N) and R
+,...,R
N
+
be the rank vectors of X = (X
1,X
N) and |X|=(|X
1|,...,|X
N|), respectively, and let V = (V
1,V
N) be the sign vector of X. The locally most powerful rank tests (LMPRT) S = S(R) and the locally most powerful signed rank tests (LMPSRT) S = S(R
+, V) will be found for testing = 0 against > 0 or < 0 with F being arbitrary and with F symmetric, respectively. 相似文献
967.
The regioselective synthesis and Diels-Alder cycloaddition of 3-(3,4-methylenedioxyphenyl)-5-bromo-2-pyrone provided a new synthetic route to crinine. The vinyl bromide group can be used as a handle for further derivatization. 相似文献
968.
Pseudorotaxane complexes of squaraine dyes and tetralactam macrocycles are converted into permanently interlocked rotaxane structures using copper-catalyzed and copper-free cycloaddition reactions with bulky stopper groups. The photophysical properties of the encapsulated squaraine depend on the structure of the macrocycle. In one case, squaraine rotaxanes are produced in near-quantitative yields and with intense near-IR fluorescence. In another case, squaraine fluorescence is greatly diminished upon macrocyclic encapsulation but the signal can be restored by dye displacement with anions. 相似文献
969.
970.
2-D GC is a logical and cost effective extension to 1-D GC for improving the separation resolution, selectivity, and peak capacity of an analytical system. The advent of electronic pressure control systems that are accurate to the third decimal place, combined with recently innovated chromatographic devices such as capillary flow technology, has eliminated many deficiencies encountered in current conventional 2-D GC by making the technique reliable and simple to implement in both production and research analytical facilities. Low thermal mass GC (LTM-GC) was successfully integrated with capillary flow technology to further enhance overall 2-D GC chromatographic system performance by providing not only faster throughput via rapid heating and cooling, but independent temperature control for each dimension to maximize separation power. As an example, despite the enhanced peak capacity obtained from conventional 2-D GC, alkyl naphthalene isomers such as 2,3-dimethyl and 1,4-dimethyl naphthalene coeluted. These two critical compounds were well resolved (R = 5.2) using 2-D GC with LTM-GC with a similar analytical time. This paper demonstrates the benefits of combining capillary flow technology with LTM-GC to provide major enhancements to conventional 2-D GC. The synergy of these techniques is highlighted with practical industrial applications. 相似文献