[Observations on the short-term effect of Lu-jian (dried bittern) on hyperlipoproteinemia in 94 cases (author's transl)].
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Blood Pressure↗
Biomedical subjects
Z F Li
Publications and source records attributed to Z F Li.
Covalent immobilization of glucose oxidase on the surface of polyaniline films graft copolymerized with acrylic acid.
Glucose oxidase (GOD) was covalently immobilized on the electroactive polyaniline (PAN) film with surface-grafted acrylic acid (AAc) polymer through the amide linkage formation between amino groups of GOD and the carboxyl groups of the grafted AAc polymer chains in the presence of a water-soluble carbodiimide. The surface structure and composition of the graft-modified and enzyme-functionalized PAN films were characterized by angle-resolved X-ray photoelectron spectroscopy (XPS). The amounts of immobilized GOD and its activity were also investigated. It was shown that the amount of immobilized GOD increased linearly with the concentration of surface-grafted AAc polymer chains. The decrease in activity of the immobilized GOD was considered to be due to, among other factors, the reduced accessibility of glucose molecules to the active sites of the enzyme and the conformational change of the GOD molecules as a result of the covalent immobilization. However, the immobilized enzyme was less sensitive to thermal inactivation as compared to that of the free form. The optimum pH value of GOD was not affected by the immobilization reaction and the pH stability range was considerably widened. The immobilized GOD also exhibits a significantly improved stability during storage in buffer solution over that of the free enzyme.
Acrylic Resins↗
A convolution algorithm for brachytherapy dose computations in heterogeneous geometries.
Currently-available brachytherapy dose computation algorithms ignore heterogeneities such as tissue-air interfaces, shielded gynecological colpostats, and tissue-composition variations in 125I implants despite dose computation errors as large as 40%. To calculate dose in the presence of tissue and applicator heterogeneities, a computer code has been developed that describes scatter dose as a 3-D spatial integral which convolves primary photon fluence with a dose-spread array. The dose-spread array describes the distribution of dose due to multiple scattering about a single primary interaction site and is precomputed by the Monte Carlo method. To correct for heterogeneities traversed by the primary photons, the dose-spread array is renormalized to reflect the density and composition of the element, and the distance to the point of interest is scaled by the path-length of the intervening medium. Convolution calculations for 125I and 137Cs point sources in the presence of finite phantoms, air voids and high-density shields have been compared to the corresponding Monte Carlo calculations. The convolution code absolute and relative dose rate predictions are shown to agree with Monte Carlo calculations within 3%. Direct evaluation of the 3-D spatial convolution integral using 1-D adaptive integration reveals efficiency gains of 20-50 relative to Monte Carlo photon-transport calculations.
Algorithms↗