The Dynamic Nuclear Polarization (DNP) effect is used at room temperature in combination with /sup 13/C NMR. Due to the low natural abundance of /sup 13/C spins (1%) the signal is very weak, but when the DNP effect is used the /sup 13/C signal can be ...

A new solid-state NMR method is described for obtaining long-range distance constraints in nanocrystalline samples of 13C-, 15N-, and 2H-enriched protein. The method selects only those 13C or 15N nuclei close to 1Hs for dipolar recoupling. When used with extensive deuteration, the bath of abundant ...

A new experimental technique based on cross polarization under magic angle spinning (CP/MAS) is introduced. This method, called CHCC, is used to quantify 1H-13C polarization transfer efficiency in high resolution 2D (13C-13C) correlation spectra of uniformly ...

Indirectly detected, through-bond NMR correlation spectra between {sup 13}C and {sup 1}H nuclei are reported for the first time in solid state. The capabilities of the new method are demonstrated using naturally abundant organic-inorganic mesoporous hybrid materials. The time performance is ...

Natural-abundance solid-state 13C nuclear magnetic resonance spectra were obtained for bacterial spores for the first time by using the technique of cross-polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. A resonance at about 150 ppm, detectable in spore samples having a Mn content of less ...

of natural abundant 13 C of the liquid crystal molecule N-4-methoxybenzylidene-4-butylaniline (MBBA were performed on MBBA, in its nematic phase (T � 297 K) using a Bruker 300 MHz (DSX) solid state NMR of the liquid crystal, MBBA. The calculated mo- tional parameters show that the molecule ...

Despite many studies of coal and related fossil fuels, no attempts have been made to systematically correlate changes in the solid state (sup 13)C-NMR parameters as a function of static field strength. In particular, questions arise regarding differences ...

Jan 22, 2011 ... Title: Solid state ***super13***C MAS NMR investigations of amorphous carbon thin films: structural changes during annealing ...

Tholins enriched in 13C and 15N were analysed through solid state 13C and 15N NMR, thus bringing new insights on their chemical structure.

Polyxylylenes are thermoplastics used as encapsulants for electronic devices. Five polyxylylenes were prepared by pyrolysis of (2.2)paracyclophanes and characterized by solid state (sup 13)C NMR spectroscopy. The chemical shift data, in combination with i...

... SOLID-STATE 13C MAGIC ANGLE SPINNING NUCLEAR MAGNETIC RESONANCE ... IT IS SHOWN THAT STRUCTURAL TRADE-OFFS PREVENT ...

Natural abundance (13)C cross polarized (CP) magic angle spinning (MAS) nuclear magnetic resonance (NMR) analysis of human gall bladder stones collected from patients suffering from malignant and benign gall bladder disease was carried out which revealed different polymorphs of cholesterol in these stones. All gall bladder stones in ...

Solid-state spectral editing techniques have been used by others to simplify 13C CPMAS spectra of small organic molecules, synthetic organic polymers, and coals. One approach utilizes experiments such as cross-polarization-with-polarization-inversion and cross-polarization-with-depolarization to generate subspectra. This work shows ...

Two-dimensional through-bond (1)H{(13)C} solid-state NMR experiments utilizing fast magic angle spinning (MAS) and homonuclear multipulse (1)H decoupling are presented. Remarkable efficiency of polarization transfer can be achieved at MAS rates exceeding 40 kHz, which is instrumental in these measurements. Schemes utilizing direct and ...

The relative orientations (phi, Psi angles) of adjacent peptide bond planes define the secondary and tertiary structure of peptides and proteins. These orientations can be determined solely on the basis of solid state NMR experiments on single crystal or uniaxially oriented samples. Examples include single crystals of peptides and the coat protein of ...

Two-dimensional through-bond 1H{13C} solid-state NMR experiments utilizing fast magic angle spinning (MAS) and homonuclear multipulse 1H decoupling are presented. Remarkable efficiency of polarization transfer can be achieved at MAS rates exceeding 40 kHz, which is instrumental in these measurements. Schemes utilizing direct and ...

Static solid state proton NMR and Magic Angle Spin (MAS) high resolution (sup 13)C NMR were performed on original and oxidized activated carbon. The (sup 13)C NMR spectra indicate that there is a relatively narrow dispersion of chemical shifts centered at...

An abstract is given of a paper in which the development of solid state NMR of exp 13 C is applied to the study of whole coals, coal processing, coal by-products, and other fuel related materials. Examples will also be given of the application of solid st...

A new approach for high-resolution solid-state heteronuclear multiple-quantum MAS NMR spectroscopy of dipolar-coupled spin-1/2 nuclei is introduced. The method is a heteronuclear chemical shift correlation technique of abundant spins, like 1H with rare spins, like 13C in natural abundance. High ...

Jun 16, 2011 � Description: Published spectroscopic observations pertaining to the crystal structure of native celluloses are reviewed for the purpose of ...

... Chemical Constituents in Ceramic Powders and Dense Bodies. ... fact, solid state (13)C imaging of polymers ... is already a significant body of literature ...

... rapidly and efficiently. Studies of AB copolymers include ring-opening polymerization of caprolactam (nylon 6 monomer) with ...

The detailed chemical structure of graphite oxide (GO), a layered material prepared from graphite almost 150 years ago and a precursor to chemically modified graphenes, has not been previously resolved because of the pseudo-random chemical functionalization of each layer, as well as variations in exact composition. Carbon-13 (13C) ...

Preparation of proteins in their crystalline state has been found to be important in producing stable therapeutic protein formulations, cross-linked enzyme crystals for application in industrial processes, generating novel porous media for separations, and of course in structure elucidation. Of these applications only X-ray crystallography requires large crystals, defined here as being crystals ...

The 1H 13C solid-state NMR heteronuclear correlation (HETCOR) experiment is demonstrated to provide shift assignments in certain powders that have two or more structurally independent molecules in the unit cell (i.e. multiple molecules per asymmetric unit). Although this class of solids is often difficult to characterize using other ...

Solid-state (sup 13)C and (sup 29)Si NMR measurements were carried out on a series of petroleum source rocks from the Mowry Formation of the Powder River Basin in Wyoming. The objectives of this study wereto use CP/MAS (sup 13)C NMR measurements to monito...

This study applies solid state (sup 13)C NMR and X-ray diffractometric studies to a wide variety of native cellulosic tissues and tertiary aggregates which simulate states of aggregation characteristic of cell walls. During this project period we have con...

A number of new approaches to the study of native wood tissue complementary to our earlier Raman spectroscopy including solid state (sup 13)C NMR and X-ray diffractometry. A wide variety of native cellulosic tissues were examined which led to the generati...

Using pyrazole and 3,5-dimethylpyrazole mixtures with alumina and silica, high-resolution solid state {sup 13}C and {sup 15}N CPMAS NMR was performed to compare the spectra. The NH-N proton tautomers resulting depend strongly on the environment. 70 refs., 8 figs., 4 tabs.

Animal manure is generally high in organic matter intensity so it is well suitable for 13C nuclear magnetic resonance (NMR) analysis. Solid-state 13C NMR techniques used in characterizing organic matter and its components include, but are not limited to, cross-polarization /magic angle spinning (CP...

Two types of swine manure chars, hydrothermally-produced hydrochar and slow-pyrolysis pyrochar, and their raw swine manure solid were characterized using advanced 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Compared with the parent raw swine manure, both hydrochars and pyrochar di...

A New Approach in 1D and 2D 13 C High-Resolution Solid-State NMR Spectroscopy of Paramagnetic for paramagnetic organometal complexes in rigid solids3-6 because of low sensitivity/resolution and difficulties in 1H decoupling associated with large paramagnetic shifts. Recent studies demonstrated that 13C, 1H

Solid state NMR (SSNMR) experiments on heteronuclei in natural abundance are described for three synthetically designed tripeptides Piv-(L)Pro-(L)Pro-(L)Phe-OMe (1), Piv-(D)Pro-(L)Pro-(L)Phe-OMe (2), and Piv-(D)Pro-(L)Pro-(L)Phe-NHMe (3). These peptides exist in different conformation as shown by solution state NMR and single crystal ...

This book contains the following chapters: Principles of solid state NMR; Relaxation processes: Introduction to pulse sequences; Quantitative analysis; Removal of artifacts from CPMAS FT experiments; Line broadening mechanisms; Resolution enhancement of solid state NMR spectra; and /sup ...

In this study, the molecular composition of dissolved organic matter (DOM), collected from wetlands of the Southern Everglades, was examined using a variety of analytical techniques in order to characterize its sources and transformation in the environment. The methods applied for the characterization of DOM included fluorescence spectroscopy, solid state ...

Effect of hydration on the dynamics of parvalbumin, a 11.5 kDa Ca2+/Mg2+-binding globular protein has been studied, at room temperature, by incoherent quasi-elastic neutron scattering and 13C solid-state NMR. Samples were protein powders hydrated at different hydration levels. The increase of the quasi-elastic signal observed in neutron scattering upon hydration is interpreted ...

... C-13 SPECTRA WERE OBTAINED AT NATURAL ABUNDANCE, THE N ... OF THIS TECHNIQUE FOR DETECTING CHEMICAL INTERACTIONS IS ...

Unstabilized polypropylene (PP) films having selective {sup 13}C isotopic labeling were subjected to thermal aging at 50, 80, and 109 C and to {gamma}-irradiation at 24 and 80 C. The oxidized films were examined using solid-state {sup 13}C nuclear magnetic resonance (NMR) spectroscopy. Dramatic ...

We have used a rotational-echo adiabatic-passage double-resonance (13)C{(17)O} solid-state NMR experiment to prove that the glycine produced in the oxygenase reaction of ribulose bisphosphate carboxylase-oxygenase is incorporated exclusively into protein (or protein precursors) of intact, water-stressed soybean leaves exposed to ...

Anaerobic sedimentary conditions have traditionally been linked to the generation of the source rocks for petroleum formation. However, the influence of sedimentary redox conditions on the composition of freshly deposited organic matter (OM) is not clear. We assessed the effect of in situ exposure time to oxic conditions on the composition of OM accumulating in different coastal and deep-sea ...

Dimethylether (DME) is a nearly prolate asymmetric top with two internal rotors (methyl groups) which undergo periodic large amplitude motions and show a complicated torsional splitting of each rotational energy level. Due to its complex spectrum and its high abundance in hot cores such as Orion KL or Sagittarius B2 at temperatures exceeding 100 K, DME is very prominent in ...

The solid state NMR technique, (sup 1)H-(sup 13)C-(sup 31)P double cross polarization (DCP)/MAS (sup 13)C-NMR spectroscopy, uses the direct dipolar interaction between (sup 13)C-(sup 31)P spin pairs in organophosphorus substances to ...

Polyxylylenes are thermoplastics used as encapsulants for electronic devices. Five polyxylylenes were prepared by pyrolysis of [2.2]paracyclophanes and characterized by solid state {sup 13}C NMR spectroscopy. The chemical shift data, in combination with interrupted decoupling experiments, allowed assignment of ...

A combination of solid-state {sup 13}C NMR, X-ray photoelectron spectroscopy (XPS) and sulfur X-ray absorption near edge structure (S-XANES) techniques are used to characterize organic oxygen, nitrogen, and sulfur species and carbon chemical/structural features in kerogens. The kerogens studied represent a wide range of organic matter types and maturities. ...

Unexpected formation of an insoluble polymer during purification of 1-cyclobutenecarboxylic acid led to solid state 13C NMR characterization which seemed to indicate vinyl polymerization was occurring. Deliberate attempts to induce radical polymerization ...

The objective of this work has been to create large polarizations of the dilute exp 13 C nuclei in the solid state. The idea was to create exp 1 H polarizations larger than Boltzmann and to use the proton enhanced nuclear induction spectroscopy cross pola...

... conditions as those used for the whole seeds. Proton NMR spectra of lipids solubilized in deuterated chloroform were recorded and compared. The spectra of lipids before and after irradiation are ... the l...

Whole cells of Methanosphaera stadtmanae were grown in media containing [13C]CO2, [2-13C]acetate, [1-13C]acetate, [3-13C]serine and [1-13C]formate. The label incorporation was determined using solid ...

Solid-state 13C MAS NMR spectra were obtained for dark-adapted bacteriorhodopsin (bR) labeled with (4'-13C)Tyr. Difference spectra (labeled minus natural abundance) taken at pH values between 2 and 12, and temperatures between 20 and -90 degrees C, exhibit a single signal centered at 156 ppm, indicating ...

Changes in the chemical composition of mangrove ( Rhizophora mangle ) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13 C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about ...

Kerogen is the insoluble fraction of organic matter in rocks and is the parent material for petroleum. Chemical structural characteristics of kerogen constrain the ability of source rocks to generate bitumen, oil, and natural gas. It is important to understand changes in kerogen structure with increasing thermal maturity to evaluate the organic-geochemical mechanisms of hydrocarbon generation. ...

Starch is subjected to chemical treatments such as cross-linking or hydroxypropylation to meet the material requirements for food uses or controlled release in the pharmaceutical industries. In this work, two types of cross-linking formulations have been employed for the preparation of high amylose starch for use as an excipient for sustained drug release. The structural differences and chain ...

Antimicrobial Peptide RTD-1 Jarrod J. Buffy, Melissa J. McCormick, Sungsool Wi, Alan Waring,� Robert I. Lehrer antimicrobial peptide isolated from rhesus macaque leukocytes. Using 31P, 2H, 13C, and 15N solid-state NMR, we the antimicrobial activity of RTD-1. 13C and 15N anisotropic chemical ...

). Unlabeled, blocked Fmoc amino acids were from Novabiochem, 13 C labeled alanine and glycine were from.2 ppm) and (73.7, 3.2, �76.8 ppm) were used for the Alanines and Glycines, respectively, in the two AG�124 with chemical shifts. The conformations of glycine residues were analyzed using doubly 13 C � O ...

Figure 20. Solid state CP/MAS 13C NMR of dry, solid RDX exposed to light for 15 days at 10-cm depth............................................................. 47 Figure 22. Liquid state 13C NMR of dry, solid Composition B exposed to light for 15 days at ...

The results of the structural and conformational studies carried out using 13C CPMAS NMR technique on several glycine and alanine containing peptides in the solid state are reported. The study demonstrates the effects of variations in 13C chemical shifts due to conformation and hydrogen bonding. The possibility of ...

Through variable-temperature solution-state NMR and molten- and solid-state CP/MAS (13)C NMR spectra, thiotropolone is found to exist as two rapidly equilibrated tautomeric structures, thione and enethiol, even in the solid state far below the melting point. The crystal structure shows an almost perpendicular ...

Solid-state 13C nuclear magnetic resonance (NMR) has been applied to an array of intact and isolated wood samples in order to identify potential structural changes induced by tree age, milling, lignin extraction, or naturally occurring mutations. Included in this study were mature loblolly pine mil...

Advanced solid-state NMR was employed to investigate differences in chemical structure and heterogeneity between milled wood lignin (MWL) and residual enzyme lignin (REL). Wiley and conventional milled woods were also studied. The advanced NMR techniques included 13C quantitative direct polarization...

Solid-state cross-polarization, magic-angle sample spinning carbon-13 nuclear magnetic resonance spectra have been recorded on chlorophyll a- water aggregates, methyl pyrochlorophyllide a and methyl pyropheophorbide a (derivatives that lack a phytyl chain...

Poly(di n-hexylsilane) has been studied in the solid state using variable temperature 13C and 29Si CPMAS NMR spectroscopy. It has been found that the silane backbone exists in different conformations above and below the thermochromic temperature transitio...

by mixing approximately equal weights of [3-13 C]alanine, [2-13C]glycine, and [1-13C]leucine (Cambridge Anisotropy Filter. Figure 3 shows the experimental CSA decay curves for the amino acids glycine and alanine, the CSA decay of glycine CR falls between of 31 and 37 ppm (assuming ) 0.4), while the of Ala C

the accumulation of ligno-protein nuclei in humic substances. Nonetheless, 13 C isotope studies of various soil and humic acids. The remaining matter (humin and minerals) was treated with HCl and HF, then extracted of lipids, humic acids, fulvic acids, and minerals. The solid state 13 ...

Four types of experiments concerning the system exp 48 Ti + exp 13 C at 46 MeV were performed: single gamma spectra; gamma -particle coincidences between a Ge(Li) detector and two solid state detectors; gamma - gamma coincidences and gamma -angular distri...

signals of adamantane at the same time as applying a modulated rf field to the 1 H spins. We show good resolution of the adamantane 13 C�1 H J�couplings by using R189 2 irradiation of the protons. We also�couplings in adamantane Figure 3 shows 13 C specta of adamantane acquired using the pulse scheme given in ...

The application of Fourier transform infrared (FT-IR) spectroscopy and solid state exp 13 C NMR spectroscopy, using magic-angle spinning in conjunction with cross-polarization and high-power decoupling has been used to obtain some parameters of coal struc...

... in the melanosomes (16). 13C solid-state nuclear magnetic resonance (NMR) analyses All 13C cross-polarization magic angle spinning (CP/MAS) NMR spectra were acquired on a Bruker Avance Spectrospin 400 ...

The modification of starch, which is the major component of the polysaccharide fraction of chestnuts (Castanea sativa), has been studied from the point of view of structure and digestibility to understand the modifications induced by cooking and, specifically, by the Maillard reaction. The study was carried out by enzymatic degradation kinetics, monitoring the glucose released upon time, and by ...

Fentanyl base and ?-cyclodextrin (?-CD) were coground at 1:1 and 1:2 molar ratios (fentanyl: ?-CD) and the physicochemical characteristics of the mixtures were studied using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), solid state (13)C nuclear magnetic resonance (NMR) ...

Ethanol is a complex organic molecule (COM), observed principally in hot core regions in the interstellar medium (e.g. Sgr B2, W51M, Orion KL, G34.3+0.15). The 13C isotopologues have not been identified in the ISM and prior to this work only scarce low-frequency laboratory data were available. Absorption spectra of both 13C isotopologues of ethanol were ...

Cross polarization (CP) magic angle spinning (MAS) 13C-NMR spectroscopy is a solid state NMR technique widely used to study chemical composition of organic materials with low or no solubility in the common deuterated solvents used to run liquid state NMR experiments. Based on the magnetization transfer from ...

Our understanding of the hydrodynamic response of peatland to climate change is restricted to the Holocene, which confines our knowledge of the fundamental controls on this important carbon reservoir to recent sedimentary successions. To understand the interaction of peatland hydrodynamics, climate and the carbon cycle on longer time scales, a 95.4 m record from lower Miocene lignite from the ...

Knowledge of (13)C chemical shift anisotropy (CSA) tensors in nucleotide bases is important for interpretation of NMR relaxation data in terms of local dynamic properties of nucleic acids and for analysis of residual chemical shift anisotropy (RCSA) resulting from weak alignment. CSA tensors for protonated nucleic acid base carbons have been derived from measurements on a uniformly ...

Solid state CP/MAS 13C nuclear magnetic resonance (NMR) study of the insoluble organic fraction isolated by HF/HCl treatment under an inert atmosphere from the Orgueil and Murchison carbonaceous meteorites is reported. Based on these spectra, eight different types of carbons (aro- and ali-linked CH3, CH2, aliphatic ...

A combination of solid-state {sup 13}C NMR, X-ray photoelectron spectroscopy (XPS) and sulfur X-ray absorption near edge structure (S-XANES) techniques are used to characterize organic oxygen, nitrogen, and sulfur species and carbon chemical/structural features in kerogens. The kerogens studied represent a wide range of organic matter types and maturities. ...

We have performed the direct measurements of (13) C magnetic shielding for pure liquid TMS, solution of 1% TMS in CDCl(3) and solid fullerene. The measurements were carried out in spherical ampoules exploring the relation between the resonance frequencies, shielding constants and magnetic moments of (13) C and (3) ...

Multidimensional solid-state NMR spectroscopy is used to refine the identification and abundance determination of functional groups in insoluble organic matter (IOM) isolated from a carbonaceous chondrite (Murchison, CM2). It is shown that IOM is composed primarily of highly substituted single ring aromatics, substituted furan/pyran moieties, highly ...

Measurements of the relative abundance of anionic species, commonly described as Qn species in silicate glasses are essential for any structure-based model of thermodynamic or transport properties of silicate liquids and magmas. Solid-state 29Si NMR has provided the most convincing evidence that the Qn species distribution in alkali glasses is not random ...

In order to develop triple-resonance solid-state NMR spectroscopy of membrane proteins, we have implemented several different (13)C labeling schemes with the purpose of overcoming the interfering effects of (13)C-(13)C dipole-dipole couplings in stationary samples. The membrane-bound form of the major coat protein of the filamentous ...

In this investigation we report a complete assignment of (13)C, (1)H and (15)N solution and solid state chemical shifts of two bacterial photosynthetic pigments, bacteriochlorophyll (BChl) a and bacteriopheophytin (BPheo) a. Uniform stable-isotope labelling strategies were developed and applied to biosynthetic preparation of photosynthetic pigments, namely ...

Benefits of the use of natural polymers include biodegradability, biocompatibility, natural abundance, and unique physicochemical/biological properties. Native alginate was used to semisynthesize a new class of biomaterial in which the physical properties such as swelling and pore size can be chemically tailored for desired end use. Semisynthetic network alginate polymer ...

Natural abundance 13C solid-state nuclear magnetic resonance spectroscopy was used to investigate the effect of the incorporation of cholesterol on the dynamics of dimyristoylphosphatidylcholine (DMPC) bilayers in the liquid-crystalline phase. In particular, the use of a combination of the cross-polarization and ...

Molecular spectroscopic evidence derived from C-XANES and 2D 13C Solid State NMR reveals that organic solids typical of primitive chondritic meteorites, Interplanetary Dust Particles (IDPs), and high O/C organic particles, returned from Comet Wild2/81P by the Stardust spacecraft, are predominantly derived from the ...

The IR, Raman, and 13C NMR spectra of lithium pyruvate monohydrate and its isotopic compounds including the O-deuterated and 18O- and 13C- analogs have been measured in the solid state. The IR and NMR spectra of aqueous solutions of the lithium, sodium, and potassium salts have also been obtained for comparison. No CO stretching band is observed in the ...

Solid-state {sup 13}C NMR spectra have been obtained of bovine rhodopsin and isorhodopsin regenerated with retinal selectively {sup 13}C labeled along the polyene chain. In rhodopsin, the chemical shifts for {sup 13}C-5, {sup ...

Insight into the chemical history of an ungrouped type 2 carbonaceous chondrite meteorite, Wisconsin Range (WIS) 91600, is gained through molecular analyses of insoluble organic matter (IOM) using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, X-ray absorption near edge structure spectroscopy (XANES), and pyrolysis-gas ...

Simple pulse schemes are presented for the measurement of methyl (13)C and (1)H CSA values from (1)H-(13)C dipole/(13)C CSA and (1)H-(13)C dipole/(1)H CSA cross-correlated relaxation. The methodology is applied to protein L and malate synthase G. Average ...

Solid-state (13)C-NMR spectroscopy was used to characterize native cellulose pellicles from two strains of Gluconacetobacter xylinus (ATCC 53582, ATCC 23769), which had been statically cultivated in Hestrin-Schramm (HS) medium containing fully (13)C-labeled ...

Magic angle sample spinning (MASS) /sup 13/C NMR spectra have been obtained of bovine rhodopsin regenerated with retinal prosthetic groups isotopically enriched with /sup 13/C at C-5 and C-14. In order to observe the /sup 13/C retinal chromophore resonances, it was ...

The solid state NMR technique, {sup 1}H-{sup 13}C-{sup 31}P double cross polarization (DCP)/MAS {sup 13}C-NMR spectroscopy, uses the direct dipolar interaction between {sup 13}C-{sup 31}P spin pairs in organophosphorus substances to ...

Sensitive 2D solid-state (13)C-(13)C correlation spectra of amyloid ? fibrils have been recorded at very fast spinning frequencies and very high magnetic fields. It is demonstrated that PARIS-xy recoupling using moderate rf amplitudes can provide structural information by promoting efficient ...

A new solid-state NMR method is presented for estimating homonuclear dipole-dipole couplings for selected groups of nuclear spins in a multiple-spin coupled network. The methodology combines off-magic-angle spinning, frequency selective spin echoes, and multiple quantum filtering. The new method is insensitive to incoherent relaxation effects and may be used to estimate weak ...

The turnover of soil organic matter (SOM) is controlled both by its chemical composition, its spatial bioavailability and the association with the mineral phase. Separation by physical fractionation of bulk soils and subsequent chemical analysis of these fractions should give insights to how compositional differences in SOM drive turnover rates of different size-defined carbon pools. The main ...

Solid-state {sup 13}C NMR spectroscopy of a series of crystalline nucleosides and nucleotides allows direct measurement of the effect of the deoxyribose ring conformation on the carbon chemical shift. It is found that 3{prime}-endo conformers have 3{prime} and 5{prime} chemical shifts significantly (5-10 ppm) upfield of comparable ...

Dermatan sulfate in the solid state has been studied by /sup 13/C CP/MAS nmr and X-ray diffraction in order to establish the ring conformation of the L-iduronate moiety. The solid state nmr spectrum is similar to the solution spectrum obtained previously, indicating that a ...