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51.
Kuberan B Beeler DL Lawrence R Lech M Rosenberg RD 《Journal of the American Chemical Society》2003,125(41):12424-12425
We have engineered a two-step enzymatic synthesis of Mitrin which is a more potent and homogeneous anticoagulant than the current animal-derived heparin. This engineered heparin may have advantages of being free from animal-derived pathogens and may also have reduced side effects such as heparin induced thrombocytopenia. This approach can also be extended to tailor heparin-based drugs with improved therapeutic characteristics to treat other disorders or infections in which heparin-like molecules play a major role. 相似文献
52.
[reaction: see text] A reversal of diastereoselectivity was observed for novel 5-(trimethylsilyl)adamantan-2-ylidene (1c) with regard to 5-hydroxyadamantan-2-ylidene (1a). Ostensibly in intermolecular reactions, 5-substituted 2-adamantanylidenes (1) are sterically unbiased. However, inductive effects originating from the pendant group bend the divalent carbon bridge of 1 either toward (ERG's, e.g., -Si(CH(3))(3)) or away from (EWG's, e.g., -OH) the gamma-position. Hence, the more exposed side is more susceptible to intermolecular reaction and the other side concomitantly undergoes intramolecular 1,3-CH insertions more readily. 相似文献
53.
Ice nucleating-active Pseudomonas fluorescens F264C was fed to Colorado potato beetles to determine bacterial retentioin in the beetle gut and its effect on the cold hardiness of this insect pest. The bacrterium was present in beetles recovered after overwintering in the field, seven months after their exposure to P. fluorescens. Retention was evident not only in the detection of the P. fluorescens ice nucleating gene, inaW, in bacterial cultures from beetle guts but also in the elevated supercooling points of some treated beetles. 相似文献
54.
55.
A new technique to heat metallic specimens, in split-Hopkinson-bar experiments, is presented. The heating is achieved with
induction coils surrounding the specimen. The main advantages of this technique are (1) a relatively fast heating rate, (2)
localization of the heated volume, and (3) heating achieved without touching the specimen. Experimental results for several
metals, in terms of high strain-rate stress-strain curves at elevated temperatures, are presented and discussed. 相似文献
56.
57.
58.
The magnetic phase diagram of amorphous Ni80? x Fe x B16Si4 was studied by de-magnetization measurement, by57Fe-Mössbauer spectroscopy and pulsed spin echo NMR. 相似文献
59.
Katarína Kla?anová Peter Fodran Michal Rosenberg 《Monatshefte für Chemie / Chemical Monthly》2010,223(5):823-828
Abstract
This work describes the degradation of phenylalanine and tryptophane catalysed by their complexes with Fe(II), Co(II), and Cu(II). The influences of the central atom and of the reaction conditions on the degradation of the amino acids were observed. The necessary condition of the degradation is the possibility of a redox reaction on the central atom between M(II) and M(III). Moreover, the coordination sphere of the central cation of the transition metal must not be sterically shielded. The necessary conditions are fulfilled only in the Fe(II) complexes. The degradation is strictly anaerobic because due to the influence of oxygen, an irreversible oxidation of Fe(II) to Fe(III) proceeds. This reaction results in 5-hydroxy-1H-indol instead of the mixture of the degradation products, such as benzaldehyde, phenylacetaldehyde, and phenylacetic acid. The influence of the temperature on the catabolism is very important because the reaction accelerates with temperature increase. The phenylalanine anion acts as a reducing agent, and Fe(II) is spontaneously reduced to Fe(0). 相似文献60.