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Ganesan K Sehgal PK Mandal AB Sayeed S 《Applied biochemistry and biotechnology》2011,165(3-4):1075-1091
The irreversible destruction of extracellular matrix (ECM) such as cartilage, tendon, and bone that comprise synovial joints is the hallmark of both rheumatoid arthritis and osteoarthritis by over-expression of matrix metalloproteinase (MMP)-collagenases. We report herein the detailed study on the inhibitory effects of Withania somnifera extract (WSE) and Cardiospermum halicacabum extract (CHE) on Clostridium histolyticum collagenase (ChC) activity against the degradation of the ECM component of bovine Achilles tendon type I collagen by hydroxyproline assay method. Interaction of WSE and CHE with ChC exhibited 71% and 88% inhibition, respectively, to the collagenolytic activity of ChC against collagen degradation, and the inhibition was found to be concentration-dependent. The inhibition kinetics of ChC by both the extracts has been deduced from the extent of hydrolysis of N-[3-(2-furyl) acryloyl]-Leu-Gly-Pro-Ala. Both WSE and CHE are provided competitive and mixed type inhibition on ChC activity, respectively. Circular dichroism studies of ChC on treatment with WSE and CHE revealed changes in the secondary structure of collagenase. These results suggest that the WSE and CHE facilitated collagen stabilization through collagenase inhibition. 相似文献
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A new look at Frobenius' original papers on character theory has produced the following: (a) the group determinant determines the group (Formanek-Sibley); (b) the group is determined by the 1-, 2- and 3-characters of the irreducible representations (Hoehnke-Johnson); and (c) pairs of non-isomorphic groups exist with the same irreducible 1- and 2-characters (Johnson-Sehgal). The examples produced in Johnson and Sehgal have large orders but, recently, McKay and Sibley have proved that the ten Brauer pairs of order 256 have the same irreducible 2-characters. It is shown here that the pairs of non-isomorphic groups of order p3, p and odd prime, have the same irreducible 2-characters. Further results are given on the k-characters of the regular representation/rod a shorter proof of the result mentioned in (c) is indicated. A criterion is given which is sufficient for the 3-character of an arbitrary representation to determine the group. 相似文献
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Ohne Zusammenfassung
Deutsch von K. Popp (Leipzig). 相似文献
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Sudarshan K. Sehgal 《manuscripta mathematica》1975,15(1):65-80
The main theorem gives necessary and sufficient conditions for the rational group algebra QG to be without (nonzero) nilpotent elements if G is a nilpotent or F·C group. For finite groups G, a characterisation of group rings RG over a commutative ring with the same property is given. As an application those nilpotent or F·C groups are characterised which have the group of units U(KG) solvable for certain fields K.This work has been supported by N.R.C. Grant No. A-5300. 相似文献
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Measurement of the acoustic nonlinearity parameter B/A in human tissues by a thermodynamic method 总被引:2,自引:0,他引:2
C M Sehgal R C Bahn J F Greenleaf 《The Journal of the Acoustical Society of America》1984,76(4):1023-1029
A thermodynamic method for measuring the acoustic nonlinearity parameter B/A in tissues is presented. It is based on the measurement of change in phase velocity as a function of time as the hydrostatic pressure of the sample is quickly reduced from a known value. This technique circumvents the effect of the attenuation in the medium and does not require a prior knowledge of the thermodynamic parameters of the tissues. The method is used to estimate nonlinearity parameters for normal and malignant tissues in the temperature range 20 degrees to 37 degrees C. The values and the temperature dependence of these parameters are found to vary with the nature of the tissues. 相似文献
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It is proved that if G is a split extension of a cyclic p-group by a cyclic p′-group with faithful action then any torsion unit of augmentation one of G is rationally conjugate to a group element. It is also proved that if G is a split extension of an abelian group A by an abelian group X with (|A|, |X|) = 1 then any torsion unit of G of augmentation one and order relatively prime to |A| is rationally conjugate to an element of X. 相似文献