نتایج جستجو برای: 1h nmr
تعداد نتایج: 79250 فیلتر نتایج به سال:
BACKGROUND Many severe diseases are caused by defects in lipid metabolism. As a result, patients often accumulate unusual lipids in their blood and tissues, and proper identification of these lipids is essential for correct diagnosis. In this study, we investigated the potential use of proton nuclear magnetic resonance (1H-NMR) spectroscopy to simultaneously identify and quantify (un)usual lipi...
در این پایان نامه مطالعه سد انرژی چرخش و محاسبه نظری پارامترهای فعالسازی ترمودینامیکی در پدیده دینامیک 1h nmr در بعضی از ترکیبات آلی از جمله ایلیدهای پایدار فسفر، انامینون، آمید غیر اشباع و انامینو استرها انجام شده است. محاسبات توسط روش hf و b3lypبا مجموعه پایه 6-31g(d,p) در فاز گازی و محلول و دمای هم آمیزی مورد مطالعه قرار گرفته است و نتایج آن توافق خوبی با مقادیر تجربی دینامیک 1h nmr دارد. ...
در این تحقیق، محاسبات مربوط به پایداری نسبی ایزومرهای چرخشی z و eدرمشتقات ایزوکینولین و فنانتریدین حاصل از واکنش بین ایزوکینولین یا فنانتریدین بااستر استیلنی در حضور مشتقات فنول در سطح hf/6-31g(d,p) گزارش می شود. نتایج بدست آمده با روش هایaim،npaو محاسبات nmr در همین سطح مورد ارزیابی قرار گرفت. در ادامه مطالعه چرخش حول پیوند یگانه و دوگانه در ایلید پایدار فسفر حاصل از واکنش بین 4-هیدروکسی بنزآل...
Indirect detection of 13C and 15N nuclear magnetic resonance (NMR) spectra through 1H NMR signals offers large sensitivity advantages in studies of organic and biological molecules in solution and is almost universally employed.1-3 Although sensitivity enhancement by indirect detection was first demonstrated in NMR4-6 and nuclear quadrupole resonance7,8 of solids, direct detection has generally...
Radix Astragali is a component of several traditional medicines used for the treatment of type 2 diabetes in China. Radix Astragali is known to contain isoflavones, which inhibit α-glucosidase in the small intestines, and thus lowers the blood glucose levels. In this study, 21 samples obtained from different regions of China were extracted with ethyl acetate, then the IC50-values were determine...
Bioassay-guided fractionation of a CHCl3 extract of the leaves of Xanthium italicum Moretti led to the isolation of four xanthanolides: xanthatin (1), 4-epixanthanol (2), 4-epi-isoxanthanol (3), and 2-hydroxyxanthinosin (4). Their structures were determined by means of 1D and 2D NMR spectroscopy, including 1H-1H COSY, NOESY, HSQC and HMBC experiments, which resulted in complete and unambiguous ...
Four new prenylxanthones, emerixanthones A-D (1-4), together with six known analogues (5-10), were isolated from the culture of the deep-sea sediment derived fungus Emericella sp. SCSIO 05240, which was identified on the basis of morphology and ITS sequence analysis. The newstructures were determined by NMR (1H, 13C NMR, HSQC, HMBC, and 1H-1H COSY), MS, CD, and optical rotation analysis. The ab...
The data included in this paper are associated with the research article entitled "Sesquiterpenoids from the cultured mycelia of Ganoderma capense" [1]. 1H NMR, 13C NMR, DEPT, HSQC, 1H-1H COSY, HMBC, NOESY, HRESIMS, and IR spectra of Ganodermanol A-H (1-11), together with Mo2(AcO)4-induced CD spectrum of Ganodermanol A, CD spectra of Ganodermanol D-E were included in the Data in Brief article. ...
Proton-detected 1H-13C heteronuclear correlated spectroscopy [( 1H,13C]-COSY) was used to establish relations between the carbon-13 and proton nuclear magnetic resonance chemical shifts in the hexadeoxynucleoside pentaphosphate d-(GCATGC)2. Using the previously established sequence-specific proton NMR assignments, sequence-specific assignments were thus obtained for nearly all proton-bearing ca...
BACKGROUND AND AIMS Plausible reasons for the failure of liver graft in liver transplantation are explored. 1H-NMR spectroscopy of serum is employed for assessment of liver graft function. Differences in concentrations of specific metabolites between patients with successful and unsuccessful liver grafts following transplantation were used as possible markers to assess the graft quality. METH...
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