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1.
Dr. Ana G. Enderle Dr. Matteo Bosso Rüdiger Groß Magdalena Heiland Dr. Mariela Bollini Dr. María J. Culzoni Prof. Dr. Frank Kirchhoff Prof. Dr. Jan Münch Prof. Dr. Carsten Streb 《ChemMedChem》2021,16(17):2727-2730
Polyoxometalates (POMs), molecular metal oxide anions, are inorganic clusters with promising antiviral activity. Herein we report increased anti-HIV-1 activity of a POM when electrostatically combined with organic counter-cations. To this end, Keggin-type cerium tungstate POMs have been combined with organic methyl-caffeinium (Caf) cations, and their cytotoxicity, antiviral activity and mode of action have been studied. The novel compound, Caf4K[β2-CeSiW11O39]×H2O, exhibits sub-nanomolar antiviral activity and inhibits HIV-1 infectivity by acting on an early step of the viral infection cycle. This work demonstrates that combination of POM anions and organic bioactive cations can be a powerful new strategy to increase antiviral activity of these inorganic compounds. 相似文献
2.
Dr. Alexander Fries Dr. Laura S. Mazzaferro Dr. Björn Grüning Dr. Philippe Bisel Karin Stibal Patrick C. F. Buchholz Prof. Dr. Jürgen Pleiss Prof. Dr. Georg A. Sprenger Prof. Dr. Michael Müller 《Chembiochem : a European journal of chemical biology》2019,20(13):1672-1677
Chorismate and isochorismate constitute branch-point intermediates in the biosynthesis of many aromatic metabolites in microorganisms and plants. To obtain unnatural compounds, we modified the route to menaquinone in Escherichia coli. We propose a model for the binding of isochorismate to the active site of MenD ((1R,2S, 5S,6S)-2-succinyl-5-enolpyruvyl-6-hydroxycyclohex-3-ene-1-carboxylate (SEPHCHC) synthase) that explains the outcome of the native reaction with α-ketoglutarate. We have rationally designed variants of MenD for the conversion of several isochorismate analogues. The double-variant Asn117Arg–Leu478Thr preferentially converts (5S,6S)-5,6-dihydroxycyclohexa-1,3-diene-1-carboxylate (2,3-trans-CHD), the hydrolysis product of isochorismate, with a >70-fold higher ratio than that for the wild type. The single-variant Arg107Ile uses (5S,6S)-6-amino-5-hydroxycyclohexa-1,3-diene-1-carboxylate (2,3-trans-CHA) as substrate with >6-fold conversion compared to wild-type MenD. The novel compounds have been made accessible in vivo (up to 5.3 g L−1). Unexpectedly, as the identified residues such as Arg107 are highly conserved (>94 %), some of the designed variations can be found in wild-type SEPHCHC synthases from other bacteria (Arg107Lys, 0.3 %). This raises the question for the possible natural occurrence of as yet unexplored branches of the shikimate pathway. 相似文献
3.
Gert Schubring 《NTM》2003,11(2):90-99
Enno Heeren Dirksen (1788–1850) was one of several mathematicians originating from Eastern Frisia at the end of the eighteenth
century to acquire prominence in neohumanist reformed Prussia. While striving—like so many of his contemporaries—for more
rigour in the foundations of calculus, his work is significant due to his unusual emphasis on the semiotic aspects of the
basic concepts. As a clear-sighted propagator of Cauchy's conceptual innovations in Germany, his achievements in improving
sign expressions of such concepts enabled him to clarify hitherto not differentiated multiple limit processes—although less
successfully in constructive concept formation itself.
The contribution is based on the analysis of Dirksen's published texts and on the numerous texts which remained drafts for
his projected voluminousOrganon der gesamten Analysis.
Menso Folkerts zum 60. Geburtstag gewidmet 相似文献
Menso Folkerts zum 60. Geburtstag gewidmet 相似文献
4.
负载型复合载体及其镍基催化剂的性能 总被引:4,自引:4,他引:0
采用溶胶-凝胶法制备了负载型ZrO_2/Al_2O_3和ZrO_2/Al_2O_3-SiO_2复合载体,研究了不同复合载体对Ni基催化剂CO_2重整甲烷反应和性能的影响,并用XRD、IR、TPR、TPD和BET等方法对复合载体及催化剂进行了表征。结果表明,ZrO_2负载在基载体后比表面积、碱性、活性组分Ni的分散度和Ni与ZrO_2的相互作用增大。NiO在复合载体表面的分散容量与ZrO_2的负载量有关,ZrO_2的负载量为37.5%时NiO的分散容量达最高值(24.0%)。与Ni/ZrO_2相比,Ni/ZrO_2/Al_2O_3-SiO_2和Ni/ZrO_2/Al_2O_3催化剂对CO_2的吸附能力增大,CO_2吸附量增加,酸强度降低,CO_2重整CH_4反应活性提高,其中以Ni/ZrO_2/Al_2O_3催化剂的活性最好。 相似文献
5.
6.
单脉冲导引头对多干扰源的角分辨 总被引:8,自引:0,他引:8
当多个噪声调频干扰同时进入单脉信号引头主波束内时,导引头对干扰源的角度分辨是非常困难的。本文主要研究了导引头单脉冲接收机对宽带噪声调频干扰源的响应,分析了当单脉冲主波束内存在多个噪声调频干扰源时,导引头指向角的跟踪规律,并重点讨论了一种用聚类来提取角信息的方法,最后仿真证实了该方法的正确性和有效性。 相似文献
7.
8.
Werner Hüning 《化学,工程师,技术》1985,57(10):850-857
Safety measures in thermal waste air purification units . Safety problems may arise in thermal waste air purification units from the occasional explosive nature of the exhaust gases, which may cause a flashback into the production plant. This must be avoided by the installation of safety devices that arrest a flashback. The number of such safety devices is determined by the probability of formation of explosive waste air, according to the zone classification of the explosion-protection guide. The principal explosion arrestor devices installed between combustion chamber and production plant are liquid submersion systems, detonation barriers, and dynamic flashback-free inlets into the combustion chamber, all of which must be operated under instrumental surveillance. This report presents a state-of-the-art summary of all suitable procedures and safety devices permitting safe design of systems for thermal air cleaning problems encountered in practice. 相似文献
9.
10.
Gert van der Horn Johan H. Huijsing 《Analog Integrated Circuits and Signal Processing》1997,14(3):207-222
In many applications electronic sensors are used toimprove performance and reliability of measurement systems. Suchsensors should provide a correct transfer from the physical signalto be measured to the electrical output signal. One importantstep to achieve this, is to calibrate each sensor by applyingdifferent reference input signals and adjusting the sensor transferaccordingly. Besides expensive reference equipment the calibrationprocess takes much time and attention per individual sensor,which means a considerable increase in sensor production costs.By including at the sensor or sensor interface chip a programmablecalibration facility the calibration of such smart sensors caneasily be automated and can be executed for a batch of sensorsat a time, thus minimizing the calibration time and costs. Thispaper presents a calibration method and options for integrationin the smart sensor concept, in hardware as well as in software.An advantage of the proposed method is that it does not needa large matrix of calibration data, which needs to be storedin a look-up table or converted into a correction formula, butinstead it uses a step-by-step approach to correct the sensortransfer at each calibration measurement until the error is sufficientlysmall. 相似文献