نتایج جستجو برای: 1h qnmr spectroscopy
تعداد نتایج: 196670 فیلتر نتایج به سال:
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...
Two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy has been used to assign 13C spectra of the tricyclic antidepressants imipramine and chlorimipramine . The 2DINADEQUATE method was used to unambiguously assign the aromatic spectral region for the former compound. Errors in previous literature assignments based on 1D methods were corrected. For chlorimipramine the pitfalls of class...
This work outlines the unequivocal identification of the "ecstasy" analog, 2-chloro-4,5-methylenedioxymethylamphetamine, using combined gas chromatography/mass spectroscopy (GC/MS) and proton magnetic resonance spectroscopy (1H-NMR). This compound was identified along with 3,4-methylenedioxymethylamphetamine (MDMA) in an illicit tablet seizure, which included 26 off-white tablets.
Purpose To determine whether pretreatment in vivo 1H magnetic resonance (MR) spectroscopy at 3 Tesla (T) and 18F-FDG PET/CT can offer predictive power regarding the local control of oropharyngeal or hypopharyngeal squamous cell carcinoma (OHSCC) patients. Materials and Methods 1H MR spectroscopy was performed in addition to conventional MR imaging before definitive chemoradiotherapy in 58 pat...
BACKGROUND Evaluation of small intestinal permeability (SIP) is based on the estimation of the urinary excretion ratio of a large and a small molecule (lactulose and mannitol, L/M) after oral administration. We evaluated SIP using 1H-NMR spectroscopy. METHODS In-vitro experiments on known concentration of mannitol and lactulose solutions were performed to measure accuracy and precession of qu...
The purpose of this study was to evaluate the role of high-resolution magic angle spinning (HR-MAS) 1H nuclear magnetic resonance (NMR) spectroscopy in patients with ductal carcinoma in situ (DCIS) diagnosed on preoperative biopsy. We investigated whether the metabolic profiling of tissue samples using HR-MAS 1H NMR spectroscopy could be used to distinguish between DCIS lesions with or without ...
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 ...
The diagnostic and prognostic potential of an onco-metabolite, 2-hydroxyglutarate (2HG) as a proton magnetic resonance spectroscopy (1H-MRS) detectable biomarker of the isocitrate dehydrogenase (IDH)-mutated (IDH-MT) gliomas has drawn attention of neuroradiologists recently. However, due to severe spectral overlap with background signals, quantification of 2HG can be very challenging. In this t...
From the ethyl acetate soluble fraction of twigs of Magnolia denudata (Magnoliaceae), seven new neolignan derivatives, 1-7, were isolated along with eighteen known lignan and neolignan derivatives, 8-25. The structures of the new neolignans were elucidated by means of spectral methods, especially by 1H-NMR and 13C-NMR spectra, and two dimensional NMR methods such as 1H-detected heteronuculear m...
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