نتایج جستجو برای: hnuclear magnetic resonance spectroscopy
تعداد نتایج: 539695 فیلتر نتایج به سال:
lipomatosis of the nerve, also known as fibrolipomatous hamartoma, is characterized by the infiltration of the nerve by fibro-fatty tissue. the affected nerve becomes thicker, and it simulates a mass lesion. lipomatosis usually affects the median nerve and lipomatosis of the sciatic nerve is extremely rare. magnetic resonance imaging (mri) is the key to diagnosis, and it is usually pathognomoni...
conclusion these data indicate that while ce-mri will depict more positive results, there are cases in which dwi will show a positive result while ce-mri is negative. we suggest that the combination of these two imaging modalities might yield more positive results in diagnosing acute ms attack giving rise to a more accurate diagnosis. results ce-mri yielded positive results for 61 (87%) patient...
the application of magnetic resonance to diagnostic medical imaging stands as one of the great scientific achievements in the past 50 years. magnetic resonance techniques are easily applied to organs which remain stationary during the imaging procedure, such as the brain and musculoskeletal system. imaging of moving heart structures and circulating blood is considerably more difficult. clinic...
The detailed conformational features and dynamics of the naturally occurring deoxyribotrinucleoside diphosphates d-TpTpT and d-TpTpC have been investigated at 20 degrees C and 80 degrees C in aqueous solution by nuclear magnetic resonance spectroscopy. The observed NMR parameters indicate that the conformational properties of the trimers are very similar to those of the constituent dimers and m...
A novel method that permits the quantitative detection and classification of various carbonyl groups in lignins has been developed. The proposed method was optimized with the quantitative trifluoromethylation of a series of carbonyl-containing lignin-like model compounds. This effort was followed by (19)F NMR spectral analyses of the resulting fluorine derivatives allowing for a thorough unders...
Four-dimensional nuclear magnetic resonance spectroscopy with high resolution of signals in the indirect dimensions is reported as an implementation of the filter diagonalization method (FDM). Using an oligosaccharide derivatized with 13C-labeled acetyl isotags, a four-dimensional constant-time pulse sequence was tailored for conjoint use with the FDM. Results demonstrate that high resolution i...
In this Letter, we present NMR spin-lattice and relaxometry data for proton transfer in one of the shortest known N-H⋯O hydrogen bonds in a single crystal of 3,5 pyridinedicarboxylic acid (35PDCA). It is widely believed that proton transfer by quantum tunneling does not occur in short hydrogen bonds since the ground state energy level lies above the potential barrier, yet these data show a temp...
Liquid-crystalline materials containing fullerenes are valuable in the development of supramolecular switches and in solar cell technology. In this study, we characterize the liquid-crystalline and dynamic properties of fullerene-containing thermotropic compounds using solid-state natural abundance (13)C NMR experiments under stationary and magic angle spinning sample conditions. Chemical shift...
A drastic reduction of the time required for two-dimensional NMR experiments can be achieved by reducing or skipping the recovery delay between successive experiments. Novel SMAll Recovery Times (SMART) methods use orthogonal pulsed field gradients in three spatial directions to select the desired pathways and suppress interference effects. Two-dimensional spectra of dilute amino acids with con...
در بین انواع نانوذره ها، نانوذره های مغناطیسی (mnps) نظر به کاربرد های بسیاری که در حوزه های مختلفی همچون مایعات مغناطیس (magnetic fluids) کاتالیز (catalysis) ، تصویربرداری رزونانس مغناطیسmagnetic resonance imaging) ) و بازسازی محیط زیست (environmental remediation) دارند توجه پژوهشگران را به خود جلب نموده اند [1]. این نانوذره ها سوپرپارامغناطیس هایی اند که می توانند جذب میدان مغاطیسی شوند اما خ...
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