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991.
Based on the determination of inorganic phosphate (the product of ATP dephosphorylation by ATPase), a method for on-line determination
of bioactivity of ATPase on cell membrane is presented, in which on-line sampling of cell membrane and separation of inorganic
phosphate is employed in a flow injection system. The method has been successfully applied to the investigation of variation
of ATPase from human umbilical vein endothelial cell membrane; the results show that ATPase activity decreases with elapsed
time studied, which may supply important information for the pertinent studies on cell membrane enzymes bioactivity. 相似文献
992.
B. Bialecki G. Fairweather A. Karageorghis Q.N. Nguyen 《BIT Numerical Mathematics》2008,48(3):449-472
We formulate new optimal quadratic spline collocation methods for the solution of various elliptic boundary value problems
in the unit square. These methods are constructed so that the collocation equations can be solved using a matrix decomposition
algorithm. The results of numerical experiments exhibit the expected optimal global accuracy as well as superconvergence phenomena.
AMS subject classification (2000) 65N35, 65N22 相似文献
993.
L J Shi Z M Ni S F Lu G Wang H L Qi Q X Su 《Science in China. Series B, Chemistry, life sciences & earth sciences》1989,32(7):816-821
Spindle fiber attachments (SFAs) were enriched in a fraction of nuclei isolated from mouse livers. The enrichment method combines sonication, treatment with 2 mol/L NaCl and high speed centrifugation. SFA was enriched 27-fold on the average (n = 4) when measured by radioimmunoassay. The basic method offers opportunities for further increases of yield and for the enrichment of SFA of other vertebrates. 相似文献
994.
995.
水/离子液体两相体系中出芽短梗霉催化4-氯-乙酰乙酸乙酯不对称还原合成(S)-4-氯-3-羟基-丁酸乙酯 总被引:2,自引:0,他引:2
考察了水/离子液体两相体系中出芽短梗霉(Aureobasidium pullulansCGMCC1244)催化4-氯乙酰乙酸乙酯(COBE)不对称还原生成光学活性(S)-4-氯-3-羟基丁酸乙酯((S)-CHBE)的性能,并对反应条件如摇床转速、相体积比、温度、初始底物浓度和pH值等进行了优化.结果表明,在水/1-丁基-3-甲基咪唑六氟磷酸盐体系中,出芽短梗霉催化COBE不对称还原生成(S)-CHBE,在30℃,pH6·6,摇床转速180r/min和不对称反应8h条件下,反应物的转化率、产物ee值和浓度分别达到95·6%,98·5%和47·1g/L.在控制pH值为6·6的情况下,通过分添加底物可有效提高产物(S)-CHBE浓度至75·1g/L. 相似文献
996.
L. Q. Ji 《Journal of Thermal Analysis and Calorimetry》2008,91(3):885-889
Three rational fraction approximations for the temperature integral have been proposed using the pattern search method. The
validity of the new approximations has been tested by some numerical analyses. Compared with several published approximating
formulas, the new approximations is more accurate than all approximations except the approximations proposed by Senum and
Yang in the range of 5≤E/RT≤100. For low values of E/RT, the new approximations are superior to Senum-Yang approximations as solutions of the temperature integral. 相似文献
997.
998.
The characteristics of the spin-flop transition in K2FeF5 and Rb2FeF5 are found by Mössbauer spectroscopy to be very different, and are discussed in relation to the ordered magnetic structures of the two systems. 相似文献
999.
Let us denote byΛ n, 1 the supremum of (max∥z∥=1∥p′ n (z)∥)/ (max∥z∥=1∥p n (z)∥) taken over all polynomialsp n of degree at mostn having a zero on the unit circle {z ∈ C∶∥z∥=1}. We show that Λn.1=n-(π 2/16)(1/n)+O(1/n 2. 相似文献
1000.
A. Q. Howard Jr 《Fiber and Integrated Optics》1977,1(2):181-196
A new, relatively simple way of calculating bend radiation is developed. As is often done in propagation over gently curved surfaces, the fiber curvature is accounted for by placing a straight fiber in a fictitious medium that is inhomogeneous in the plane of the bend. For a gently curved fiber, the medium is slowly varying and the WKB method is used to approximate the radial field dependence. This solution is related to the unperturbed straight fiber solution through an ansatz consistent with the WKB solution. The propagating modes in this approximation remain orthogonal, allowing an immediate generalization to the multimoded case. The radiation loss per unit length is calculated two ways and is consistent with results in the literature. 相似文献