نتایج جستجو برای: nuclear magnetic resonance spectroscopy

تعداد نتایج: 750760  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده شیمی 1384

این رساله شامل سه بخش می باشد. در بخش نخست مطالعاتی در زمینه تهیه تترازولها با کایرالیته محوری انجام گردیده است و در این راستا مشتقات آریلوکسی تترازول بی نفتول و 2- متوکسی 2- هیدروکسی بی نفتیل تترازول در فر م های راسمیک و فعال نوری تهیه شده اند. سپس روشی برای جداسازی انانتیومرهای ارائه شده است . همچنین از ترکیب 5 و ترکیب مزیتیلوکسی تترازول ایمیدوئیل آزیدهای مربوطه تهیه گردید و از آنها در ...

Journal: :Journal of Agricultural and Food Chemistry 2021

The structural heterogeneity of water-extractable arabinoxylan (WE-AX) impacts wheat flour functionality. 1H diffusion-ordered (DOSY) nuclear magnetic resonance (NMR) spectroscopy revealed structur...

1-Methyl-1H-imidazol-3-ium 2,3,4,5,6-pentafluorophenolate [mim]C6F5O as a novel nano ionic liquid was designed, synthesized and characterized by using various techniques such as Fourier transform spectroscopy infrared (FT-IR), nuclear magnetic resonance (NMR), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ener...

2010
Aaron M. Socha Gerald Kagan Weibin Li Russell Hopson Jason K. Sello Paul G. Williard

Biodiesel, fatty acid methyl esters derived from vegetable oils, is a well-established alternative to petroleum diesel. We have developed a rapid H diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY NMR)method to resolve mixtures of mono-, di-, and triacyglycerols alongwith their methyl esters. Because of the differences in diffusion coefficients between the starting materials (tri...

Journal: :The European respiratory journal 1992
P Jakobsson L Jorfeldt

Nuclear magnetic resonance spectroscopy provides non-invasive and non-destructive access to the chemistry of human tissue in situ. Two studies presented in this issue of the Journal [1, 2] apply this new technique on skeletal muscle metabolism in patients with chronic lung disease. In the 1940s, E. Purcell and F. Bloch discovered that electromagnetic radio-frequency energy could be used to inte...

Journal: :Plant physiology 1988
N Tyler C Stushnoff L V Gusta

Various empirical prefreezing protocols have been used to facilitate cryopreservation of dormant buds from woody plants. The objective of this research was to determine the quantity of water remaining in liquid phase, under different prefreezing conditions using pulsed nuclear magnetic resonance spectroscopy of dormant apple (Malus domestica Mill.) buds from three cultivars. During prefreezing,...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Smaranda C Marinescu Jay R Winkler Harry B Gray

Several cobalt complexes catalyze the evolution of hydrogen from acidic solutions, both homogeneously and at electrodes. The detailed molecular mechanisms of these transformations remain unresolved, largely owing to the fact that key reactive intermediates have eluded detection. One method of stabilizing reactive intermediates involves minimizing the overall reaction free-energy change. Here, w...

Journal: :Journal of the American Chemical Society 2009
Alfonso De Simone Barbara Richter Xavier Salvatella Michele Vendruscolo

The dynamics of proteins plays a central role in their activity, including enzymatic catalysis and allosteric communication. Many advances have been made in recent years in the characterization of the equilibrium fluctuations of proteins through experimental and computational methods. We present evidence that the use of molecular dynamics simulations with ensemble-averaged structural restraints...

Journal: :Chemphyschem : a European journal of chemical physics and physical chemistry 2014
Kevin J Donovan Adonis Lupulescu Lucio Frydman

Dissolution dynamic nuclear polarization (DNP) enables high-sensitivity solution-phase NMR experiments on long-lived nuclear spin species such as (15)N and (13)C. This report explores certain features arising in solution-state (1)H NMR upon polarizing low-γ nuclear species. Following solid-state hyperpolarization of both (13)C and (1)H, solution-phase (1)H NMR experiments on dissolved samples r...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1980
E T Fossel H E Morgan J S Ingwall

Levels of the high-energy phosphate-containing compounds, ATP and creatine phosphate, and of inorganic phosphate (Pi) were measured as a function of position in the cardiac cycle. Measurements were made on isolated, perfused, working rat hearts through the use of gated 31P nuclear magnetic resonance spectroscopy. Levels of ATP and creatine phosphate were found to vary during the cardiac cycle a...

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