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101.
Density functional theory (B3LYP) and ab initio theory [second-order M?ller-Plesset perturbation theory (MP2) and coupled-cluster theory including single, double, and quasiperturbative triple excitations (CCSD(T))] have been used in combination with the standard and augmented correlation consistent basis sets (cc-pVnZ and aug-cc-pVnZ, where n = D, T, and Q) to investigate potential new noble gas compounds. Two classes of molecules were studied: XNgCCNgX and XNgCCX, where Ng = Kr and Ar and X = F and Cl. These molecules were characterized by finding the ground-state structures and calculating the relative energies, charge distributions, and vibrational frequencies. In addition, transition-state structures were also determined and decomposition pathways were identified through intrinsic reaction coordinate calculations. 相似文献
102.
Wildemann D Schiene-Fischer C Aumüller T Bachmann A Kiefhaber T Lücke C Fischer G 《Journal of the American Chemical Society》2007,129(16):4910-4918
psi[CS-NH]4-RNase S, a site specific modified version of RNase S obtained by thioxylation (O/S exchange) at the Ala4-Ala5- peptide bond, was used to evaluate the impact of protein backbone photoswitching on bioactivity. psi[CS-NH](4)-RNase S was yielded by recombination of the S-protein and the respective chemically synthesized thioxylated S-peptide derivative. Comparison with RNase S revealed similar thermodynamic stability of the complex and an unperturbed enzymatic activity toward cytidine 2',3'-cyclic monophosphate (cCMP). Reversible photoisomerization with a highly increased cis/trans isomer ratio of the thioxopeptide bond of psi[CS-NH](4)-RNase S in the photostationary state occurred under UV irradiation conditions (254 nm). The slow thermal reisomerization (t(1/2) = 180 s) permitted us to determine the enzymatic activity of cis psi[CS-NH](4)-RNase S by measurement of initial rates of cCMP hydrolysis. Despite thermodynamic stability of cis psi[CS-NH](4)-RNase S, its enzymatic activity is completely abolished but recovers after reisomerization. We conclude that the thioxopeptide bond modified polypeptide backbone represents a versatile probe for site-directed photoswitching of proteins. 相似文献
103.
104.
Dr. Robert Wieduwild Swati Krishnan Karolina Chwalek Annett Boden Mirko Nowak David Drechsel Prof. Dr. Carsten Werner Dr. Yixin Zhang 《Angewandte Chemie (International ed. in English)》2015,54(13):3962-3966
Hydrogel beads as microcarriers could have many applications in biotechnology. However, bead formation by noncovalent cross‐linking to achieve high cell compatibility by avoiding chemical reactions remains challenging because of rapid gelation rates and/or low stability. Here we report the preparation of homogeneous, tunable, and robust hydrogel beads from peptide–polyethylene glycol conjugates and oligosaccharides under mild, cell‐compatible conditions using a noncovalent crosslinking mechanism. Large proteins can be released from beads easily. Further noncovalent modification allows for bead labeling and functionalization with various compounds. High survival rates of embedded cells were achieved under standard cell culture conditions and after freezing the beads, demonstrating its suitability for encapsulating and conserving cells. Hydrogel beads as functional system have been realized by generating protein‐producing microcarriers with embedded eGFP‐secreting insect cells. 相似文献
105.
H. E. Annett und Haridas Sen 《Fresenius' Journal of Analytical Chemistry》1922,61(8-9):366-367
Ohne Zusammenfassung 相似文献
106.
Jakub Adam Koza Margitta Uhlemann Annett Gebert Ludwig Schultz 《Electrochemistry communications》2008,10(9):1330-1333
The effect of a uniform magnetic field in perpendicular-to-electrode configuration, on the hydrogen evolution reaction was investigated during the deposition of Fe and CoFe alloys. It was found that the desorption of hydrogen is supported in a magnetic field. This effect is discussed in details with respect to the micro-magnetohydrodynamic convection, which arises due to the fluctuation of the current distribution close to the H2 bubble. 相似文献
107.
B. Gawlik Martine Druges Michele Bianchi Angelo Bortoli Antonius Kettrup Herbert Muntau 《Analytical and bioanalytical chemistry》1997,358(3):441-445
The quality of the aquatic and marine environment can be monitored by the determination of pollutants in organisms living in this environment. Certified reference materials and well-organised proficiency tests are powerful means of ensuring a constant level of quality and verifying the correct application of standardised methods. The preparation of a tuna fish proficiency testing material for the evaluation of quality of As and Hg monitoring in seafood is described. Preparation and characterisation of the material as well as studies on its homogeneity and stability are described. Concentrations of 3.4 ± 0.2 mg/kg total arsenic and 2.91 ± 0.09 mg/kg total mercury have been determined as target values. Moreover indicative values for some trace elements (Cd, Cu, Ni, Pb, Sr) and some major constituents (Al, Br, C, Ca, Cl, Fe, H, K, Mg, N, Na, P, S, Si, Zn) have also been measured. 相似文献
108.
Bettina Lommel Andreas Beusch Willi Hartmann Annett Hübner Birgit Kindler Jutta Steiner Vera Yakusheva 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(2):977-980
Titanium-50 (50Ti) is an important and often requested ion beam for nuclear physics’ experiments. While natural titanium of very high purity is available in different forms; enriched material can only be bought as the dioxide or the tetrachloride. These compounds cannot be processed from currently available ion sources with a sufficient beam quality and sufficient beam intensity for a long time. We describe here the process of converting titanium dioxide into the metal, the material analysis of the starting material as well as of the reduced material. Despite varying contamination levels of silicon, chlorine, and tin in the primary materials, we obtained high yields of metallic titanium with different contamination levels. The obtained metallic 50Ti was applied at the accelerator UNILAC for the production of a high intensity ion beam for several month of beam time. 相似文献
109.
B. M. Gawlik A. Lamberty H. Muntau J. Pauwels 《Analytical and bioanalytical chemistry》2001,370(2-3):220-223
An overview is given on the development, properties, and application of the European reference soil set – the EUROSOILS. The introduction of this new type of reference material has, for the first time, enabled comparison of data related to the interaction of chemical substances with the soil, and thus, improvement of soil quality. Because of their unforeseen success, a second generation of EUROSOILS had been produced and the range of application extended to other types of measurement related to the soil matrix – soil pH, carbon and nitrogen content, particle-size distribution and cation-exchange capacity. Other fields of application include analytical method development or testing of soil decontamination techniques. On the basis of the success of the EUROSOIL concept and the need for a common basis for comparison of soil-related data in Europe and beyond, the European Commission’s Institute for Reference Materials and Measurements decided to certify several properties of the second EUROSOIL-generation, thus establishing a common QA/ QC system for soil-related data. The main features of the EUROSOILS, their origin, the necessary field and laboratory work, and some interesting background information about the project are presented in this paper. 相似文献
110.