کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10378377 880754 2005 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Structured water in partially dehydrated yeast cells and at partially hydrophobized fumed silica surface
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Structured water in partially dehydrated yeast cells and at partially hydrophobized fumed silica surface
چکیده انگلیسی
Nonfreezable water structured due to interaction with endocellular objects in yeast cells (endocellular water) or with partially hydrophobic fumed silica (interfacial water) was studied by means of 1H NMR spectroscopy with layer-by-layer freezing-out of bulk water and quantum chemical methods applied to water clusters in the gas and liquid (chloroform and cyclohexene) phases and adsorbed on silylated silica. Variation in cell hydration as well as in amount of water adsorbed on modified fumed silica leads to changes in the ratio between contributions of two water states characterized by NMR chemical shifts at δH=1.1-1.7 and 4-5 ppm. Lowering of hydration and temperature results in an enhancement of the first signal, and the opposite result is observed for the second signal. These effects may be explained by structured water distribution in the form of relatively large nanodroplets (δH=4-5ppm is close to that for bulk water) and small clusters of the 2D structure, in which the fraction of hydrogen atoms out of the hydrogen bonds (δH=1.1-1.7ppm) is larger than that in nanodroplets.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 283, Issue 2, 15 March 2005, Pages 329-343
نویسندگان
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