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591.
592.
N. H. Furman E. R. Caley I. C. Schoonover R. A. Mc Cance H. L. Shipp G. van der Lingen G. B. van Kampen L. Westenberg W. U. Behrens E. M. Emmert E. Rupp A. Poggendorf G. F. Smith A. C. Shead H. Tollert B. Kamiénski K. Karczewski T. Gaspar 《Analytical and bioanalytical chemistry》1933,94(9-10):350-355
593.
594.
Ernst-August Behrens 《Mathematische Annalen》1941,118(1):85-93
Ohne Zusammenfassung 相似文献
595.
Peer evaluation is used by the international accreditation organisations IAF and ILAC as a tool to harmonise the results of
accreditation of conformity assessment bodies and as a control mechanism to ensure constantly competent services according
to harmonized standards. Upon positive evaluation outcome, the accreditation body may join an Arrangement (MLA/MRA) between
accreditation bodies, confirming systematic reliability and competence to the market. The objective of these Arrangements
is that they will cover all accreditation bodies in all countries in the world, thus eliminating the need for suppliers of
products or services to be certified in each country where they sell their products or services. This article is to aid single
accreditation bodies wishing to sign these Arrangements in the future, and, furthermore, to communicate the procedure and
the relevance of evaluation to the public in order to build up confidence in such Arrangements. 相似文献
596.
Biosynthesis of the molybdenum cofactor in bacteria is described with a detailed analysis of each individual reaction leading to the formation of stable intermediates during the synthesis of molybdopterin from GTP. As a starting point, the discovery of molybdopterin and the elucidation of its structure through the study of stable degradation products are described. Subsequent to molybdopterin synthesis, the molybdenum atom is added to the molybdopterin dithiolene group to form the molybdenum cofactor. This cofactor is either inserted directly into specific molybdoenzymes or is further modified by the addition of nucleotides to the molybdopterin phosphate group or the replacement of ligands at the molybdenum center. 相似文献
597.
Behrens CR Hooker JM Obermeyer AC Romanini DW Katz EM Francis MB 《Journal of the American Chemical Society》2011,133(41):16398-16401
A highly efficient protein bioconjugation method is described involving addition of anilines to o-aminophenols in the presence of sodium periodate. The reaction takes place in aqueous buffer at pH 6.5 and can reach high conversion in 2-5 min. The major product was characterized using X-ray crystallography, which revealed that an unprecedented oxidative ring contraction occurs after the coupling step. The compatibility of the reaction with protein substrates has been demonstrated through attachment of small molecules, polymer chains, and peptides to p-aminophenylalanine residues introduced into viral capsids through amber stop codon suppression. Coupling of anilines to o-aminophenol groups derived from tyrosine residues is also described. The compatibility of this method with thiol modification chemistry is shown through attachment of a near-IR fluorescent chromophore to cysteine residues inside the viral capsid shells, followed by attachment of integrin-targeting RGD peptides to anilines on the exterior surface. 相似文献
598.
Rannes JB Ioannou A Willies SC Grogan G Behrens C Flitsch SL Turner NJ 《Journal of the American Chemical Society》2011,133(22):8436-8439
A directed evolution approach has been used for the generation of variants of galactose oxidase (GOase) that can selectively oxidize glycans on glycoproteins. The aldehyde function introduced on the glycans D-mannose (Man) and D-N-acetyl glucosamine (GlcNAc) by the enzyme variants could then be used to label the glycoproteins and also whole cells that display mannosides on their surface. 相似文献
599.
Hydrous silicate glasses with compositions along the join diopside-anorthite (An, CaAl(2)Si(2)O(8))-(Di, CaMgSi(2)O(6)) containing up to 3 wt. % H(2)O were synthesized at temperatures 1523-1723 K and pressures of 200 MPa in an internally heated gas pressure vessel. The water content of the glasses was analyzed by Karl-Fischer titration. Infrared microspectroscopy was used to test the homogeneity of the water distribution and to measure the concentrations of OH groups and H(2)O molecules before and after conductivity measurements. The electrical conductivity was measured by impedance spectroscopy at temperature up to 685 K. A positive correlation between water content and conductivity was observed for An(100) from 0 to 1.8 wt.% H(2)O, for An(50)Di(50) (in mol.%) from 1.5 to 2.8 wt.% H(2)O, and for Di(100) from 0 to 1.2 wt.% H(2)O. At same water content of ~1.2 wt.%, the conductivity was three orders of magnitude higher in Di(100) than in the other two glasses, emphasizing the importance of non-bridging oxygens on the transport of hydrous charge carriers. Consistent with findings in literature, we conclude that protons are the predominant mobile charge carriers in alkali-free hydrous silicate glasses. Conductivity data were evaluated in terms of proton diffusivity by the Nernst-Einstein equation. The obtained diffusion coefficients range from 10(-17) m(2)/s for An(50)Di(50) with 1.50 wt.% of H(2)O at 596 K to 10(-12) m(2)/s for An(50)Di(50) with 2.77 wt.% of H(2)O at 685 K. 相似文献
600.
Franziska Debatin Karsten Behrens Dr. Jens Weber Dr. Igor A. Baburin Prof. Dr. Arne Thomas Dr. Johannes Schmidt Dr. Irena Senkovska Prof. Dr. Stefan Kaskel Alexandra Kelling Dr. Niklas Hedin Dr. Zoltan Bacsik Dr. Stefano Leoni Prof. Dr. Gotthard Seifert Prof. Dr. Christian Jäger Dr. Christina Günter Prof. Dr. Uwe Schilde Dr. Alwin Friedrich Prof. Dr. Hans‐Jürgen Holdt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(37):11630-11640
We report on a new series of isoreticular frameworks based on zinc and 2‐substituted imidazolate‐4‐amide‐5‐imidate (IFP‐1–4, IFP=imidazolate framework Potsdam) that form one‐dimensional, microporous hexagonal channels. Varying R in the 2‐substitued linker (R=Me (IFP‐1), Cl (IFP‐2), Br (IFP‐3), Et (IFP‐4)) allowed the channel diameter (4.0–1.7 Å), the polarisability and functionality of the channel walls to be tuned. Frameworks IFP‐2, IFP‐3 and IFP‐4 are isostructural to previously reported IFP‐1. The structures of IFP‐2 and IFP‐3 were solved by X‐ray crystallographic analyses. The structure of IFP‐4 was determined by a combination of PXRD and structure modelling and was confirmed by IR spectroscopy and 1H MAS and 13C CP‐MAS NMR spectroscopy. All IFPs showed high thermal stability (345–400 °C); IFP‐1 and IFP‐4 were stable in boiling water for 7 d. A detailed porosity analysis was performed on the basis of adsorption measurements by using various gases. The potential of the materials to undergo specific interactions with CO2 was investigated by measuring the isosteric heats of adsorption. The capacity to adsorb CH4 (at 298 K), CO2 (at 298 K) and H2 (at 77 K) at high pressure were also investigated. In situ IR spectroscopy showed that CO2 is physisorbed on IFP‐1–4 under dry conditions and that both CO2 and H2O are physisorbed on IFP‐1 under moist conditions. 相似文献