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51.
The purpose of the present note is to provide a somewhat more flexible statement of the sufficiency conditions in Section 4 of Ref. 1 and to give explicit statements of the fundamental necessity and sufficiency results, which were only implicitly presented there. The additional flexibility is obtained by considering local, rather than global, pseudoconcavity requirements. 相似文献
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Blindauer CA Polfer NC Keiper SE Harrison MD Robinson NJ Langridge-Smith PR Sadler PJ 《Journal of the American Chemical Society》2003,125(11):3226-3227
Using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry, we show that one Zn2+ ion in the Zn4 cluster of cyanobacterial metallothionein is inert to exchange with 67Zn2+. We suggest that this is zinc in site A, which together with the surrounding alpha and beta secondary structure forms a zinc-finger fold. 相似文献
57.
Solid phase microextraction in combination with capillary GC-MS was used as monitoring technique for the collection and detection of the fungal volatile metabolite (+)-aristolochene by sporulated surface cultures of Penicillium roqueforti. A comparison was made between different toxigenic and nontoxigenic strains of P. roqueforti. Different growth conditions and media, such as malt extract agar, potato dextrose agar and sabouraud dextrose agar were compared. Whereas toxigenic strains produced large amounts of (+)-aristolochene, beta-elemene, valencene and germacrene A, nontoxigenic P. roqueforti strains showed a remarkably different headspace profile, in which ethyl-2-hexenoate, E-beta-caryophyllene, aromadendrene and beta-patchoulene were the predominant volatiles, apart from other sesquiterpene hydrocarbons present at lower concentrations. Stir bar sorptive extraction, was also applied in the headspace sampling mode, i.e. headspace sorptive extraction (HSSE) for the enrichment of fungal volatiles from sporulated surface cultures to differentiate between toxigenic and nontoxigenic fungi. Hence, it can be concluded that headspace analysis of volatile fungal metabolites by SPME and HSSE in combination with capillary GC-MS is a suitable monitoring technique for the fast detection of mycotoxin producing fungi. 相似文献
58.
Surface-confined telechelic poly(ε-caprolactone) macroligand with two distinct functional groups per polymeric chain has been synthesized and characterized. The molecular microstructure of the macroligand with regard to the properties of the end-capped functionalities and with those on surface substrate has been studied by solution and surface analytical methods (i.e., X-ray photoelectron spectroscopy (XPS), grazing angle reflectance-Fourier transform IR spectroscopy (GA-FTIR), water contact angle measurements, and atomic force microscopy (AFM)) to elucidate the structure and properties of such multifunctional polymer on gold (1 1 1) substrate. 相似文献
59.
Synthesis and functional pharmacological effects on human bronchi of 20-hydroxyeicosatetraenoic acid
A. Proteau-Gagne F. St-Jean C. Morin L. Gendron E. Rousseau Y. L. Dory 《Chemistry of Natural Compounds》2011,46(6):841-847
We have synthesized 20-hydroxyeicosatetraenoic acid (20-HETE) following a new route and delineated its functional effects
in human bronchi. Isometric tension measurements were performed, and they demonstrated that synthetic 20-HETE induced a concentration-dependent
relaxant effect in ASM on resting tone and on bronchi pre-contracted with methacholine. 相似文献
60.