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211.
212.
Binding interaction of transition metals copper, cadmium, and mercury with heme proteins were explored using isothermal calorimetry. Consequent conformational changes of the native proteins analyzed by circular dichroic spectroscopy revealed differential structural alteration of heme proteins. But, significant distortion in myoglobin structure was noted due to bioconjugation with mercury whose greater ionic radius may be responsible for this preferential behavior. 相似文献
213.
214.
Amarendra Patra Alok K. Mitra Swapna Biswas Chitra Das Gupta Ajoy Basak A. K. Barua 《Magnetic resonance in chemistry : MRC》1981,16(1):75-77
Carbon-13 NMR signal assignments of the labdane diterpenoids andrographolide and 14-deoxyandrographolide, along with their acetates, and isodeoxyandrographolide have been made. This study indicates that the C-6 and C-11 resonance assignments of isovirescenol-B, made earlier, should be interchanged. 相似文献
215.
Basak A Bag SS Majumder PA Das AK Bertolasi V 《The Journal of organic chemistry》2004,69(20):6927-6930
The synthesis and chemical reactivity of pyridazinedione-based enediynes (1, 2) are described. Both of these enediynes, namely the dihydro compound 1 and its corresponding tetrahydro analogue 2, were prepared by double N,O-alkylation of the corresponding heterocyclic system with the acyclic enediynyl dibromide 8 in good yields. Their single-crystal X-ray structures revealed similar c, d distances (distance between the acetylenic carbons undergoing covalent connection in Bergman cyclization). Interestingly, these molecules undergo Bergman cyclization at different rates, and the reactivity is shown to be dependent upon the state of hybridization of C-4 and C-5 atoms of the parent heterocyclic ring. 相似文献
216.
217.
A new approach to geminally alkylated azaphthalans and an application of this chemistry to the synthesis of the pyridone alkaloid, cerpegin, is reported. 相似文献
218.
A. K.F. Haque M. A. Uddin M. A.R. Patoary A. K. Basak M. R. Talukder B. C. Saha K. R. Karim F. B. Malik 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):203-210
The recently modified Kolbenstvedt (MKLV) model [Eur. Phys. J. D 37, 361 (2006)], developed for electron impact ionization (EII) of the K-shell atomic targets, has been extended to generalize
its two parameters in terms of the electronic orbitals nl. The generalized MKLV
(GKLV) with two sets of the species independent parameters for the same nl,
one set for the ionization of inner orbits and another for the outermost orbit, is found
profoundly successful in accounting for the EII cross section data of the K, L and M-shell neutral atoms with atomic numbers
Z = 1-92 for the incident energies up to 1000 MeV
in a consistent manner. 相似文献
219.
220.
The high degree of virulence and potential for development of a pandemic strain of the H5N1 avian flu has resulted in wide interest in characterization of the various genes of the H5N1 virus genome. We have considered for our analysis all 173 available complete sequences, as of February 2006, of the neuraminidase gene, which is the target of the most effective treatment regimen comprising the inhibitors oseltamivir and zanamivir. We have used a 2D graphical representation of the neuraminidase RNA sequences of H5N1 strains to identify a few distinct structural motifs. The H5N1 strains were split into two main classes: strains that were benign to human beings in the years up to 1996 and the period 1999-2002 and strains that were highly pathogenic to humans in the periods 1997 and 2003 to present. Comparisons with earlier H1N1 pandemic and epidemic strains have also been made to understand the current status of the gene. Our findings indicate that the base composition and distribution patterns are significantly different in the two periods, and this may be of interest in studying mutational changes in such viral genes. 相似文献