نتایج جستجو برای: 2d nmr

تعداد نتایج: 138579  

In the last five decades study on plant secondary metabolites have been increasing. Higher plants with a wide range of secondary metabolites have been very important in the search of new therapeutic agents. Flavonoids are most widely distributed secondary natural metabolites that found in plants which occuring in free forms or as glycosides with polyphenolic structure. In this study secondary m...

Journal: :Tissue engineering. Part C, Methods 2008
Christopher Seagle Megan A Christie Jason H Winnike Randall E McClelland John W Ludlow Thomas M O'Connell Michael P Gamcsik Jeffrey M MacDonald

We report a high-throughput (HTP) nuclear magnetic resonance (NMR) method for analysis of media components and a metabolic schematic to help easily interpret the data. Spin-lattice relaxation values and concentrations were measured for 19 components and 2 internal referencing agents in pure and 2-day conditioned, hormonally defined media from a 3-dimensional (3D) multicoaxial human bioartificia...

2009
Noritsugu Terashima Takuya Akiyama Sally Ralph Dmitry Evtuguin Carlos Pascoal Neto Jim Parkås Magnus Paulsson Ulla Westermark John Ralph

In the structural analysis of lignins by 13C-NMR, signal overlap limits definitive assignment and accurate inten­ sity measurement. Selective labeling by 13C-enrichment of a specific carbon in lignin enhances its signal intensity in the spectrum. Further enhancement of the specifically labeled carbons can be realized via difference spectra created from the enriched and unenriched samples. Diffe...

Journal: :Journal of magnetic resonance 2000
J R Sachleben P Beverwyk L Frydman

Aseries of uni- and multidimensional variants of the dipolar exchange-assisted recoupling (DEAR) NMR experiment is described and applied to determinations of (13)C-(14)N dipolar local field spectra in amino acids and dipeptides. The DEAR protocol recouples nearby nuclei by relying on differences in their relative rates of longitudinal relaxation, and has the potential to give quantitative geome...

Journal: :Physical review letters 2006
M Wilkening W Küchler P Heitjans

7Li stimulated-echo NMR and classical relaxation NMR techniques are jointly used for the first time for a comprehensive investigation of Li diffusion in layer-structured Li0.7TiS2. One single 2D Li diffusion process was probed over a dynamic range of almost 10 orders of magnitude. So far, this is the largest dynamic range being measured by 7Li NMR spectroscopy directly, i.e., without the help o...

Journal: :Journal of agricultural and food chemistry 2012
José C del Río Jorge Rencoret Pepijn Prinsen Ángel T Martínez John Ralph Ana Gutiérrez

The structure of the lignin in wheat straw has been investigated by a combination of analytical pyrolysis, 2D-NMR, and derivatization followed by reductive cleavage (DFRC). It is a p-hydroxyphenyl-guaiacyl-syringyl lignin (with an H:G:S ratio of 6:64:30) associated with p-coumarates and ferulates. 2D-NMR indicated that the main substructures present are β-O-4'-ethers (∼~75%), followed by phenyl...

Journal: :Phytochemistry 2000
N K Ishikawa K Yamaji S Tahara Y Fukushi K Takahashi

Cuparene-type sesquiterpenes were isolated from a culture broth of Flammulina velutipes (Curt.:Fr.) Sing. Using spectroscopic methods (HR-MS, 1H and 13C NMR, and 2D NMR, spectroscopy), their structures were determined to be 2,3,4,5-tetrahydro-2,7-dihydroxy-5,8,10,10-tetramethyl-2,5-methano-1- benzoxepin and 5-methyl-2-(3-oxo-1,2,2-trimethylcyclopentyl)benzoquinone. Both showed antimicrobial act...

Journal: :Journal of Asian natural products research 2007
X-Z Yang C-P Tang C-Q Ke Y Ye

Two new dihydrostilbenes, stilbostemins H (1), I (2), and a new dihydrophenanthrene, stemanthrene E (3), were isolated and identified from the roots of Stemona sessilifolia, together with known stilbostemins B, D and G, and stemanthrenes A and C (4-8). Structures of new stilbenoids were established by 1D and 2D (1)H NMR and (13)C NMR spectroscopic analyses.

Journal: :The Analyst 2015
Jean-Nicolas Dumez Jonas Milani Basile Vuichoud Aurélien Bornet Julie Lalande-Martin Illa Tea Maxime Yon Mickaël Maucourt Catherine Deborde Annick Moing Lucio Frydman Geoffrey Bodenhausen Sami Jannin Patrick Giraudeau

Natural abundance (13)C NMR spectra of biological extracts are recorded in a single scan provided that the samples are hyperpolarized by dissolution dynamic nuclear polarization combined with cross polarization. Heteronuclear 2D correlation spectra of hyperpolarized breast cancer cell extracts can also be obtained in a single scan. Hyperpolarized NMR of extracts opens many perspectives for meta...

Journal: :Bioinformatics 2011
Francesca Chignola Silvia Mari Tim J. Stevens Rasmus H. Fogh Valeria Mannella Wayne Boucher Giovanna Musco

SUMMARY We present here the freely available Metabolomics Project resource specifically designed to work under the CcpNmr Analysis program produced by CCPN (Collaborative Computing Project for NMR) (Vranken et al., 2005, The CCPN data model for NMR spectroscopy: development of a software pipeline. Proteins, 59, 687-696). The project consists of a database of assigned 1D and 2D spectra of many c...

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