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Most studies of collection development mask inadequate theoretical underpinnings with facile assumptions and dazzling statistical manipulations. This essay, in moving toward a model for collection development within both specific collections and library systems as a whole, seeks to demonstrate the full range and complexity of relevant factors. An enlarged theoretical grasp should help highlight both the possibilities and the challenges of existing approaches. One result could be a shift toward gaming or simulation techniques as more realistic analytical tools. 相似文献
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Seema Bhargava R. Parakh L. M. Srivastava 《Indian journal of clinical biochemistry : IJCB》2004,19(1):76-78
Homocysteine (Hcy) is a non-protein forming amino-acid, whose metabolism is at the intersection of two metabolic pathways:
remethylation and transsulfuration which are dependent on the vitamins folic acid, B12 and B6, and the enzymes methylenetetrahydrofolate reductase and cystathionine-β-synthetase. A deficiency of any of these vitamins
or enzymes results in hyperhomocysteinemia. This causes oxidative and other damage to blood vessels, thus affecting various
organ systems of the body. As part of our ongoing research on cardiovascular risk factors, we have studied the Hcy levels
in the plasma of normal controls and those suffering from vascular diseases. It was observed that Hcy is significantly higher
in patients of vascular diseases (21.59±1.28 μmol/L, mean±SEM), as compared to normal controls (11.33±0.18 μmol/L). This significance,
was more pronounced in cases of venous thrombosis (26.77±2.43 μmol/L) as opposed to cases of arterial block (17.27±0.84 μmol/L).
This signifies that Hcy estimation would be beneficial in obtaining a differential diagnosis in addition to being a modifiable
vascular risk factor. 相似文献
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