نتایج جستجو برای: Trace element
تعداد نتایج: 263901 فیلتر نتایج به سال:
غربالگری، جداسازی و بررسی خصوصیات بیوشیمیایی آنزیم کیتیناز مقاوم به دما حاصل از باکتری های بومی کشور
کیتین n(c8h13o5n ) دومین پلیمر مهم از نظر فراوانی درجهان است. کیتین از پیش ساز فعالudp-n- acetylglucoseamine به وسیله آنزیم کیتین سینتاز، سنتز می شود. مقدار کیتین از سخت پوستان در کل محیط های دریایی 1560 میلیون تن تخمین زده شده است. اسکلت خارج سلولی سخت پوستان (پوسته خرچنگ، لابستر ومیگو) به طور متداول از اصلی ترین منابع زیستی کیتین می باشد. میکروارگانیسم ها اولین تجزیه کننده های کیتین در طبیعت ...
background: within the context of developing techniques to facilitate the diagnosis of the thyroid diseases, the elemental composition of pathological thyroid tissue (neoplastic and non-neoplastic) was investigated by proton induced x-ray emission. the pixe has been widely used as a sensitive technique for trace elemental analysis in both biological and medical fields. materials and methods: th...
it is obvious that lead intake is of concern not for its beneficial/essential effects on metabolism, but rather for its toxic actions, which can be especially damaging to children. the objective of this study was to analyze the concentration of lead in milk of mothers during prolonged lactation. milk samples from 43 mothers were collected at 2 months postpartum. lead was analyzed using atomic a...
the concentration contents of ca, mg, sr and zn in porites corals from pulau langkawi, pulau redang and pulau tioman were presented. the corals were cleaned and the growth rate examined visually. the growth rate of porites in malaysia waters was between 5 to 25 mm yr-1 and each band was selected for determining the metal contents using the atomic absorption spectrophotometer (aas). the mean val...
a combined electrodeposition-etaas technique has been applied to the analysis of pb, cd, co, ni, cr and mn in biological samples in order to overcome interferences and to minimize sample pretreatment. it requires minimal sample preparation with the electrolysis process aiding partial decomposition of the organic matrix, adequate for the release and deposition of trace elements. in an initial el...
background : breast cancer is the most common invasive cancer in females worldwide. it accounts for 16% of all female cancers and 22.9% of invasive cancers in women. 18.2% of all cancer deaths worldwide including both males and females are from breast cancer. in this study we compared few serum elements in patients with benign and malignant breast tumor to find any related prognostic and predic...
There were no considerable up to date on the trace element requirements of commercial poultry in recent years in despite of the progress in their performance traits. One of the more prevalent problems in modern broiler production system which could be attributed to the trace mineral inadequacy is skeletal disorders. Zinc, is an essential trace element which acts as a co-factor in several metalo...
background: a powerful and improved technique, proton induced x-ray emission (pixe) has been performed-yielding the elemental composition of 17 samples of surgically excised malignant and normal tumors of breast tissue. the samples without any further process as thick targets were put on capton foil backing. there are no homogenizing processes. the pixe spectra analysis was performed using he n...
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