Log in

Relevant bibliographies by topics / 13C nuclear magnetic resonance. eng / Journal articles

To see the other types of publications on this topic, follow the link: 13C nuclear magnetic resonance. eng.

Journal articles on the topic '13C nuclear magnetic resonance. eng'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic '13C nuclear magnetic resonance. eng.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Gao, Song, Ed S. Mooberry, and James L. Steele. "Use of 13C Nuclear Magnetic Resonance and Gas Chromatography To Examine Methionine Catabolism by Lactococci." Applied and Environmental Microbiology 64, no. 12 (1998): 4670–75. http://dx.doi.org/10.1128/aem.64.12.4670-4675.1998.

Full text

Abstract:

ABSTRACT Formation of methanethiol from methionine is widely believed to play a significant role in development of cheddar cheese flavor. However, the catabolism of methionine by cheese-related microorganisms has not been well characterized. Two independent methionine catabolic pathways are believed to be present in lactococci, one initiated by a lyase and the other initiated by an aminotransferase. To differentiate between these two pathways and to determine the possible distribution between the pathways, 13C nuclear magnetic resonance (NMR) performed with uniformly enriched [13C]methionine w

APA, Harvard, Vancouver, ISO, and other styles

2

Fitzpatrick, Susan M., Hoby P. Hetherington, Kevin L. Behar, and Robert G. Shulman. "The Flux from Glucose to Glutamate in the Rat Brain in vivo as Determined by 1-Observed, 13C-Edited NMR Spectroscopy." Journal of Cerebral Blood Flow & Metabolism 10, no. 2 (1990): 170–79. http://dx.doi.org/10.1038/jcbfm.1990.32.

Full text

Abstract:

The rate of incorporation of carbon from [1-13C]glucose into the [4-CH2] and [3-CH2] of cerebral glutamate was measured in the rat brain in vivo by 1H-observed, 13C-edited (POCE) nuclear magnetic resonance (NMR) spectroscopy. Spectra were acquired every 98 s during a 60-min infusion of [1-13C]glucose. Complete time courses were obtained from six animals. The measured intensity of the unresolved [4-13CH2] resonances of glutamate and glutamine increased exponentially during the infusion and attained a steady state in ∼20 min with a first-order rate constant of 0.130 ± 0.010 min−1 (t1/2 = 5.3 ± 0

APA, Harvard, Vancouver, ISO, and other styles

3

Braach-Maksvytis, V. L., and B. A. Cornell. "Chemical shift anisotropies obtained from aligned egg yolk phosphatidylcholine by solid-state 13C nuclear magnetic resonance." Biophysical Journal 53, no. 5 (1988): 839–43. http://dx.doi.org/10.1016/s0006-3495(88)83163-1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

MacKenzie, N. E., E. A. Van De Waa, P. R. Gooley, et al. "Comparison of glycolysis and glutaminolysis in Onchocerca volvulus and Brugia pahangi by 13C nuclear magnetic resonance spectroscopy." Parasitology 99, no. 3 (1989): 427–35. http://dx.doi.org/10.1017/s0031182000059151.

Full text

Abstract:

SummaryComparison of glycolysis in Brugia pahangi and Onchocerca volvulus by C nuclear magnetic resonance (NMR) spectroscopy showed that the former organism is predominantly a lactate fermenter and the latter resembles more closely the metabolism of a mixed acid fermenter producing lactate, succinate, acetate, ethanol, formate and carbon dioxide. Both organisms synthesize glycogen as a storage carbohydrate. Glutaminolysis in both organisms proceeds by the δ-aminobutyrate shunt to produce succinate which is then further metabolized to acetate and carbon dioxide as end-products.

APA, Harvard, Vancouver, ISO, and other styles

5

Reese, Paul B., Laird A. Trimble, and John C. Vederas. "Detection of deuterium labelling by two-dimensional 1H,13C nuclear magnetic resonance shift correlation with 2H decoupling." Canadian Journal of Chemistry 64, no. 7 (1986): 1377–84. http://dx.doi.org/10.1139/v86-236.

Full text

Abstract:

Methylene groups that are stereospecifically labelled with deuterium can be easily observed using deuterium-decoupled 2-dimensional proton/carbon nmr shift correlation spectroscopy in either normal or CH-selective mode. Application of the technique to [3-2H]camphors 2, 3, and 4 shows that overlap of other 13C resonances does not interfere with the 2H detection. Such experiments with [3-2H]-N-benzoylphenylalanine methyl esters 6 and 7 demonstrate that identification of labelled diastereotopic hydrogens can be done if they are separated by 0.1 ppm in the 1H nmr spectrum. Fully deuterated carbons

APA, Harvard, Vancouver, ISO, and other styles

6

Ronda, Joan Carles, Angels Serra, Ana Mantecón, and Virginia Cádiz. "End-group analysis of poly(phenyl glycidyl ether), 1. Hydroxylic groups using 1H and 13C nuclear magnetic resonance." Macromolecular Chemistry and Physics 195, no. 10 (1994): 3445–57. http://dx.doi.org/10.1002/macp.1994.021951013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Beynon, Linda M., James C. Richards, Malcolm B. Perry, and Peter J. Kniskern. "Antigenic and structural relationships within group 19 Streptococcuspneumoniae: chemical characterization of the specific capsular polysaccharides of types 19B and 19C." Canadian Journal of Chemistry 70, no. 1 (1992): 218–32. http://dx.doi.org/10.1139/v92-033.

Full text

Abstract:

The specific capsular polysaccharides of Streptococcuspneumoniae types 19B and 19C (American types 58 and 59) were investigated by a combination of 1H, 13C, and 31P nuclear magnetic resonance spectroscopy and analytical methods based on mass spectrometry. The two polysaccharides were found to be high molecular weight polymers composed of L-rhamnose, 2-amino-2-deoxy-D-mannose, D-ribose, D-glucose, and phosphate. Homo- and heteronuclear chemical shift correlation techniques and nuclear Overhauser enhancement experiments led to the unambiguous assignment of the 1H and 13C resonances from the glyc

APA, Harvard, Vancouver, ISO, and other styles

8

Nizovtsev, Alexander P., Aliaksandr L. Pushkarchuk, Sergei Ya Kilin, et al. "Hyperfine Interactions in the NV-13C Quantum Registers in Diamond Grown from the Azaadamantane Seed." Nanomaterials 11, no. 5 (2021): 1303. http://dx.doi.org/10.3390/nano11051303.

Full text

Abstract:

Nanostructured diamonds hosting optically active paramagnetic color centers (NV, SiV, GeV, etc.) and hyperfine-coupled with them quantum memory 13C nuclear spins situated in diamond lattice are currently of great interest to implement emerging quantum technologies (quantum information processing, quantum sensing and metrology). Current methods of creation such as electronic-nuclear spin systems are inherently probabilistic with respect to mutual location of color center electronic spin and 13C nuclear spins. A new bottom-up approach to fabricate such systems is to synthesize first chemically a

APA, Harvard, Vancouver, ISO, and other styles

9

Xavier, Karina B., Milton S. da Costa, and Helena Santos. "Demonstration of a Novel Glycolytic Pathway in the Hyperthermophilic Archaeon Thermococcus zilligii by13C-Labeling Experiments and Nuclear Magnetic Resonance Analysis." Journal of Bacteriology 182, no. 16 (2000): 4632–36. http://dx.doi.org/10.1128/jb.182.16.4632-4636.2000.

Full text

Abstract:

ABSTRACT The operation of a novel glycolytic pathway was demonstrated in nongrowing cells of Thermococcus zilligii by analysis of the isotopic enrichment in the end products derived from fermentation of 13C-labeled glucose. The new pathway involved the formation of formate, derived from C-1 in glucose, via cleavage of a six-carbon carboxylic acid.

APA, Harvard, Vancouver, ISO, and other styles

10

González-Rodríguez, Irene, Paula Gaspar, Borja Sánchez, Miguel Gueimonde, Abelardo Margolles, and Ana Rute Neves. "Catabolism of Glucose and Lactose in Bifidobacterium animalis subsp. lactis, Studied by13C Nuclear Magnetic Resonance." Applied and Environmental Microbiology 79, no. 24 (2013): 7628–38. http://dx.doi.org/10.1128/aem.02529-13.

Full text

Abstract:

ABSTRACTBifidobacteria are widely used as probiotics in several commercial products; however, to date there is little knowledge about their carbohydrate metabolic pathways. In this work, we studied the metabolism of glucose and lactose in the widely used probiotic strainBifidobacterium animalissubsp.lactisBB-12 byin vivo13C nuclear magnetic resonance (NMR) spectroscopy. The metabolism of [1-13C]glucose was characterized in cells grown in glucose as the sole carbon source. Moreover, the metabolism of lactose specifically labeled with13C on carbon 1 of the glucose or the galactose moiety was det

APA, Harvard, Vancouver, ISO, and other styles

11

Copeland, K. R., R. W. Yatscoff, and R. M. McKenna. "Immunosuppressive activity of cyclosporine metabolites compared and characterized by mass spectroscopy and nuclear magnetic resonance." Clinical Chemistry 36, no. 2 (1990): 225–29. http://dx.doi.org/10.1093/clinchem/36.2.225.

Full text

Abstract:

Abstract Eight cyclosporine (CsA) metabolites were isolated from the urine of renal-transplant patients by high-pressure liquid chromatography. Structure and purity of the metabolites were assessed by fast atomic bombardment/mass spectroscopy, by proton nuclear magnetic resonance (NMR), and, when the quantity of metabolites permitted, by 13C-NMR. The immunosuppressive activities (I) of the metabolites were tested in three separate in vitro systems: primary and secondary mixed lymphocyte reactions as well as by a mitogen-stimulated system. The I, as measured by comparing the concentration of ea

APA, Harvard, Vancouver, ISO, and other styles

12

Chung, Yi-Hsiu, Kuan-Ying Lu, Shao-Chieh Chiu, et al. "Early Imaging Biomarker of Myocardial Glucose Adaptations in High-Fat-Diet-Induced Insulin Resistance Model by Using 18F-FDG PET and [U-13C]glucose Nuclear Magnetic Resonance Tracer." Contrast Media & Molecular Imaging 2018 (July 12, 2018): 1–10. http://dx.doi.org/10.1155/2018/8751267.

Full text

Abstract:

Background. High-fat diet (HFD) induces systemic insulin resistance leading to myocardial dysfunction. We aim to characterize the early adaptations of myocardial glucose utility to HFD-induced insulin resistance. Methods. Male Sprague–Dawley rats were assigned into two groups, fed a regular chow diet or HFD ad libitum for 10 weeks. We used in vivo imaging of cardiac magnetic resonance (CMR), 18F-FDG PET, and ex vivo nuclear magnetic resonance (NMR) metabolomic analysis for the carbon-13-labeled glucose ([U-13C]Glc) perfused myocardium. Results. As compared with controls, HFD rats had a higher

APA, Harvard, Vancouver, ISO, and other styles

13

Ronda, Joan Carles, Angels Serra, Ana Mantecón, and Virginia Cádiz. "End-group analysis of poly(phenyl glycidyl ether), 3. Isopropoxy and chlorine groups using 1H and 13C nuclear magnetic resonance." Macromolecular Chemistry and Physics 196, no. 2 (1995): 599–609. http://dx.doi.org/10.1002/macp.1995.021960215.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Hage, Maha El, Justine Masson, Agnès Conjard-Duplany, Bernard Ferrier, Gabriel Baverel, and Guy Martin. "Brain Slices from Glutaminase-Deficient Mice Metabolize Less Glutamine: A Cellular Metabolomic Study with Carbon 13 NMR." Journal of Cerebral Blood Flow & Metabolism 32, no. 5 (2012): 816–24. http://dx.doi.org/10.1038/jcbfm.2012.22.

Full text

Abstract:

In the brain, glutaminase is considered to have a key role in the provision of glutamate, a major excitatory neurotransmitter. Brain slices obtained from wild-type (control) and glutaminase-deficient (GLS1 +/–) mice were incubated without glucose and with 5 or 1 mmol/L [3-13C]glutamine as substrate. At the end of the incubation, substrate removal and product formation were measured by both enzymatic and carbon 13 nuclear magnetic resonance (13C-NMR) techniques. Slices from GLS1 +/– mice consumed less [3-13C]glutamine and accumulated less [3-13C]glutamate. They also produced less 13CO2 but accu

APA, Harvard, Vancouver, ISO, and other styles

15

Hsiao, P. C., and S. L. Lo. "Extractability and fractionation of heavy metals in chemically treated sewage sludges." Water Science and Technology 44, no. 10 (2001): 91–94. http://dx.doi.org/10.2166/wst.2001.0590.

Full text

Abstract:

Four chemically treated sludges, lime-treated (LS), lime/sodium silicate-treated (LSS), cement-treated (CS), and cement/sodium silicate-treated (CSS) were produced form the chemical treatment of aerobic digested sewage sludge cake, using lime, cement, and sodium silicate as additives. Ex tractability and fractionation of the heavy metals (Cu, Pb, Cr, and Zn) in these products and untreated sludge (S) were investigated using sequential extraction, single extraction, and 13C cross-polarization magic angle spinning nuclear magnetic resonance analysis (13C-NMR). These approaches revealed that chem

APA, Harvard, Vancouver, ISO, and other styles

16

Ferain, T., A. N. Schanck, and J. Delcour. "13C nuclear magnetic resonance analysis of glucose and citrate end products in an ldhL-ldhD double-knockout strain of Lactobacillus plantarum." Journal of bacteriology 178, no. 24 (1996): 7311–15. http://dx.doi.org/10.1128/jb.178.24.7311-7315.1996.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Roussel, R., G. Velho, P. G. Carlier, L. Jouvensal, and G. Bloch. "In vivo NMR evidence for moderate glucose accumulation in human skeletal muscle during hyperglycemia." American Journal of Physiology-Endocrinology and Metabolism 271, no. 3 (1996): E434—E438. http://dx.doi.org/10.1152/ajpendo.1996.271.3.e434.

Full text

Abstract:

Although the absence of intracellular (IC) free glucose is direct evidence of glucose transport being the rate-limiting step for muscle glucose disposal at euglycemia, the scarcity of data in humans during hyperglycemia precludes any definitive conclusion. In the present study, 13C and 31P in vivo nuclear magnetic resonance (NMR) data from two separate groups of subjects were combined to measure IC free glucose in the human skeletal muscle. When these noninvasive tools were used with an infusion of [1-13C]glucose, a steady-state concentration of 1.2 +/- 0.2 mmol IC glucose/l IC water was obser

APA, Harvard, Vancouver, ISO, and other styles

18

Zeng, Jianying, Jia Liu, Guo-Yuan Yang, Mark J. S. Kelly, Thomas L. James, and Lawrence Litt. "Exogenous Ethyl Pyruvate versus Pyruvate during Metabolic Recovery after Oxidative Stress in Neonatal Rat Cerebrocortical Slices." Anesthesiology 107, no. 4 (2007): 630–40. http://dx.doi.org/10.1097/01.anes.0000281898.01966.1e.

Full text

Abstract:

Background Exogenous pyruvate and ethyl pyruvate (EP), the key ingredient in a new Ringer's solution in clinical trials, are antioxidants as well as metabolic substrates. In vivo studies show both to be protective in oxidative stress, with EP being better. The authors used an acute rat brain slice preparation to compare EP and pyruvate rescue after H(2)O(2) oxidative stress, asking whether EP was again better and whether its actions were exclusively metabolic. Methods Oxygenated neonatal P7 cerebrocortical slices were exposed for 1 h to 2 mM H(2)O(2), and recovered for 4 h with artificial cere

APA, Harvard, Vancouver, ISO, and other styles

19

Abdel-Mageed, Wael M., Ali A. El-Gamal, Shaza M. Al-Massarani, et al. "Sterols and Triterpenes from Dobera glabra Growing in Saudi Arabia and Their Cytotoxic Activity." Plants 10, no. 1 (2021): 119. http://dx.doi.org/10.3390/plants10010119.

Full text

Abstract:

A new lupane caffeoyl ester, lup-20(29)-ene 3β-caffeate-30-al (7), and a new oleanane-type triterpene, 3β-hydroxyolean-13(18)-en-12-one (17), were isolated from the aerial parts of Dobera glabra (Forssk), along with ten known triterpenes, including seven lupane-type lupeol (1), 30-nor-lup-3β-ol-20-one (2), ∆1-lupenone (3), lup-20(29)-en-3β,30-diol (4), lupeol caffeate (5), 30-hydroxy lup-20(29)-ene 3β-caffeate (6), and betunaldehyde (8); three oleanane-type compounds were also identified, comprising δ-amyrone (15), δ-amyrin (16), and 11-oxo-β-amyrin (18); together with six sterols, comprising

APA, Harvard, Vancouver, ISO, and other styles

20

Abdel-Mageed, Wael M., Ali A. El-Gamal, Shaza M. Al-Massarani, et al. "Sterols and Triterpenes from Dobera glabra Growing in Saudi Arabia and Their Cytotoxic Activity." Plants 10, no. 1 (2021): 119. http://dx.doi.org/10.3390/plants10010119.

Full text

Abstract:

A new lupane caffeoyl ester, lup-20(29)-ene 3β-caffeate-30-al (7), and a new oleanane-type triterpene, 3β-hydroxyolean-13(18)-en-12-one (17), were isolated from the aerial parts of Dobera glabra (Forssk), along with ten known triterpenes, including seven lupane-type lupeol (1), 30-nor-lup-3β-ol-20-one (2), ∆1-lupenone (3), lup-20(29)-en-3β,30-diol (4), lupeol caffeate (5), 30-hydroxy lup-20(29)-ene 3β-caffeate (6), and betunaldehyde (8); three oleanane-type compounds were also identified, comprising δ-amyrone (15), δ-amyrin (16), and 11-oxo-β-amyrin (18); together with six sterols, comprising

APA, Harvard, Vancouver, ISO, and other styles

21

Ajoy, A., R. Nazaryan, K. Liu, et al. "Enhanced dynamic nuclear polarization via swept microwave frequency combs." Proceedings of the National Academy of Sciences 115, no. 42 (2018): 10576–81. http://dx.doi.org/10.1073/pnas.1807125115.

Full text

Abstract:

Dynamic nuclear polarization (DNP) has enabled enormous gains in magnetic resonance signals and led to vastly accelerated NMR/MRI imaging and spectroscopy. Unlike conventional cw-techniques, DNP methods that exploit the full electron spectrum are appealing since they allow direct participation of all electrons in the hyperpolarization process. Such methods typically entail sweeps of microwave radiation over the broad electron linewidth to excite DNP but are often inefficient because the sweeps, constrained by adiabaticity requirements, are slow. In this paper, we develop a technique to overcom

APA, Harvard, Vancouver, ISO, and other styles

22

Carreau, Anne-Marie, Eunsook S. Jin, Yesenia Garcia-Reyes, et al. "A simple method to monitor hepatic gluconeogenesis and triglyceride synthesis following oral sugar tolerance test in obese adolescents." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 317, no. 1 (2019): R134—R142. http://dx.doi.org/10.1152/ajpregu.00047.2019.

Full text

Abstract:

Hepatic energy metabolism is a key element in many metabolic diseases. Hepatic anaplerosis provides carbons for gluconeogenesis (GNG) and triglyceride (TG) synthesis. We aimed to optimize a protocol that measures hepatic anaplerotic contribution for GNG, TG synthesis, and hepatic pentose phosphate pathway (PPP) activity using a single dose of oral [U−13C3]glycerol paired with an oral sugar tolerance test (OSTT) in a population with significant insulin resistance. The OSTT (75 g glucose + 25 g fructose) was administered to eight obese adolescents with polycystic ovarian syndrome (PCOS) followed

APA, Harvard, Vancouver, ISO, and other styles

23

Bouajila, J., G. Raffin, S. Alamercery, H. Waton, C. Sanglar, and M. F. Grenier-Loustalot. "Phenolic Resins (IV). Thermal Degradation of Crosslinked Resins in Controlled Atmospheres." Polymers and Polymer Composites 11, no. 5 (2003): 345–57. http://dx.doi.org/10.1177/096739110301100501.

Full text

Abstract:

The study involved the thermal degradation of phenolic resins in controlled atmospheres (inert and oxidizing). Its aim was to characterize volatile organic compounds (VOC) and inorganic compounds released during heat treatment. The methods used were thermogravimetry coupled with thermodesorption/gas chromatography/mass spectrometry (TG/TCT/GC/MS) and thermogravimetric analysis coupled with infrared (TGA/IR). At the end of the heat cycle, residues were characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (solid state 13C NMR (CP/MAS)). The data show tha

APA, Harvard, Vancouver, ISO, and other styles

24

Hamerton, Ian. "High-Performance Thermoset–Thermoset Polymer Blends: A Review of the Chemistry of Cyanate Ester–Bismaleimide Blends." High Performance Polymers 8, no. 1 (1996): 83–95. http://dx.doi.org/10.1088/0954-0083/8/1/006.

Full text

Abstract:

Various blends of a commercial bismaleimide (BMI) mixture, a cyanate ester (CE) and a co-monomer with allyl and cyanate pendant groups were formulated and cured. Differential scanning calorimetry (DSC) data were used to monitor the cure of neat resins, while dynamic mechanical thermal analysis (DMTA) was used to assess cure by the measurement of glass transition temperatures ( Tg). It is suggested that following cyclotrimerization of the CE component, the co-reaction between allyl CE and BMI occurs via an ‘ene’/Diels–Alder mechanism (to form linked interpenetrating networks, LIPNs) as evidence

APA, Harvard, Vancouver, ISO, and other styles

25

Poulhazan, Alexandre, Alexandre Arnold, Dror Warschawski, and Isabelle Marcotte. "Unambiguous Ex Situ and in Cell 2D 13C Solid-State NMR Characterization of Starch and Its Constituents." International Journal of Molecular Sciences 19, no. 12 (2018): 3817. http://dx.doi.org/10.3390/ijms19123817.

Full text

Abstract:

Starch is the most abundant energy storage molecule in plants and is an essential part of the human diet. This glucose polymer is composed of amorphous and crystalline domains in different forms (A and B types) with specific physicochemical properties that determine its bioavailability for an organism, as well as its value in the food industry. Using two-dimensional (2D) high resolution solid-state nuclear magnetic resonance (SS-NMR) on 13C-labelled starches that were obtained from Chlamydomonas reinhardtii microalgae, we established a complete and unambiguous assignment for starch and its con

APA, Harvard, Vancouver, ISO, and other styles

26

Su, Weike, Zhuoni Hou, and Xianrui Liang. "Separation of avermectin components from Streptomyces avemitilis extraction using high-speed counter-current chromatography." Chemical Industry and Chemical Engineering Quarterly 19, no. 4 (2013): 563–71. http://dx.doi.org/10.2298/ciceq120410089s.

Full text

Abstract:

Three compounds of antibiotics-avermectins from fertilizing product of Streptomyces avemitilis are achieved by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (6:4:5:5, v/v) on a preparative scale. The separation condition was: 1.5 mL/min (0 to 200 min) and 2.0 mL/min (200 to the end), 900 rpm and 20?C based on the peak resolution. About 11.9 mg of avermectin B1a, 1.0 mg of avermectin B1b and 9.6 mg of avermectin B2a from 50 mg of crude extract were obtained by one-step separation. The purities of the three com

APA, Harvard, Vancouver, ISO, and other styles

27

Tingaut, Philippe, Oliver Weigenand, Holger Militz, Bernard De Jéso, and Gilles Sèbe. "Functionalisation of wood by reaction with 3-isocyanatopropyltriethoxysilane: Grafting and hydrolysis of the triethoxysilane end groups." Holzforschung 59, no. 4 (2005): 397–404. http://dx.doi.org/10.1515/hf.2005.065.

Full text

Abstract:

Abstract The chemical modification of maritime pine sapwood (Pinus pinaster Soland) with 3-isocyanatopropyltriethoxysilane (IPTES) and its subsequent hydrolysis were investigated. The formation of urethane linkages after the carbamoylation reaction was confirmed by Fourier-transform infrared (FTIR) spectroscopy. The weight percent gain (WPG) obtained was found to be commensurate with the quantity of IPTES in the reagent solution. Swelling measurements combined with scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis showed that the reaction occurred within the wood cell wal

APA, Harvard, Vancouver, ISO, and other styles

28

DiNuzzo, Mauro. "Kinetic Analysis of Glycogen Turnover: Relevance to Human Brain 13C-NMR Spectroscopy." Journal of Cerebral Blood Flow & Metabolism 33, no. 10 (2013): 1540–48. http://dx.doi.org/10.1038/jcbfm.2013.98.

Full text

Abstract:

A biophysical model of the glycogen molecule is developed, which takes into account the points of attack of synthase and phosphorylase at the level of the individual glucose chain. Under the sole assumption of steric effects governing enzyme accessibility to glucosyl residues, the model reproduces the known equilibrium structure of cellular glycogen at steady state. In particular, experimental data are reproduced assuming that synthase (1) operates preferentially on inner chains of the molecule and (2) exhibits a faster mobility than phosphorylase in translocating from an attacked chain to ano

APA, Harvard, Vancouver, ISO, and other styles

29

Katsivela, Eleftheria, Victor Wray, Dietmar H. Pieper, and Rolf-Michael Wittich. "Initial Reactions in the Biodegradation of 1-Chloro-4-Nitrobenzene by a Newly Isolated Bacterium, Strain LW1." Applied and Environmental Microbiology 65, no. 4 (1999): 1405–12. http://dx.doi.org/10.1128/aem.65.4.1405-1412.1999.

Full text

Abstract:

ABSTRACT Bacterial strain LW1, which belongs to the familyComamonadaceae, utilizes 1-chloro-4-nitrobenzene (1C4NB) as a sole source of carbon, nitrogen, and energy. Suspensions of 1C4NB-grown cells removed 1C4NB from culture fluids, and there was a concomitant release of ammonia and chloride. Under anaerobic conditions LW1 transformed 1C4NB into a product which was identified as 2-amino-5-chlorophenol by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. This transformation indicated that there was partial reduction of the nitro group to the hydroxylamino substitue

APA, Harvard, Vancouver, ISO, and other styles

30

Brekke, Eva MF, Tora S. Morken, Marius Widerøe, Asta K. Håberg, Ann-Mari Brubakk, and Ursula Sonnewald. "The Pentose Phosphate Pathway and Pyruvate Carboxylation after Neonatal Hypoxic-Ischemic Brain Injury." Journal of Cerebral Blood Flow & Metabolism 34, no. 4 (2014): 724–34. http://dx.doi.org/10.1038/jcbfm.2014.8.

Full text

Abstract:

The neonatal brain is vulnerable to oxidative stress, and the pentose phosphate pathway (PPP) may be of particular importance to limit the injury. Furthermore, in the neonatal brain, neurons depend on de novo synthesis of neurotransmitters via pyruvate carboxylase (PC) in astrocytes to increase neurotransmitter pools. In the adult brain, PPP activity increases in response to various injuries while pyruvate carboxylation is reduced after ischemia. However, little is known about the response of these pathways after neonatal hypoxia-ischemia (HI). To this end, 7-day-old rats were subjected to uni

APA, Harvard, Vancouver, ISO, and other styles

31

Jamin, Eric, Frédérique Martin, Gilles G. Martin, et al. "Determination of the 13C/12C Ratio of Ethanol Derived from Fruit Juices and Maple Syrup by Isotope Ratio Mass Spectrometry: Collaborative Study." Journal of AOAC INTERNATIONAL 87, no. 3 (2004): 621–31. http://dx.doi.org/10.1093/jaoac/87.3.621.

Full text

Abstract:

Abstract A collaborative study of the carbon-13 isotope ratio mass spectrometry (13C-IRMS) method based on fermentation ethanol for detecting some sugar additions in fruit juices and maple syrup is reported. This method is complementary to the site-specific natural isotope fractionation by nuclear magnetic resonance (SNIF-NMR) method for detecting added beet sugar in the same products (AOAC Official Methods 995.17 and 2000.19), and uses the same initial steps to recover pure ethanol. The fruit juices or maple syrups are completely fermented with yeast, and the alcohol is distilled with a quant

APA, Harvard, Vancouver, ISO, and other styles

32

Möller, A., K. Kaiser, W. Amelung, et al. "Forms of organic C and P extracted from tropical soils as assessed by liquid-state 13C- and 31P-NMR spectroscopy." Soil Research 38, no. 5 (2000): 1017. http://dx.doi.org/10.1071/sr99111.

Full text

Abstract:

Transformation of soil organic phosphorus (SOP) is linked with the transformation of soil organic carbon (SOC). Yet, it is uncertain to which SOC structures the cycling of SOP is related, especially in tropical environments. To clarify this issue, we determined the vertical distribution of extractable C and P chemical structures in 4 soil profiles using solution 13C- and 31P-nuclear magnetic resonance (NMR) spectroscopy after extraction with 0.1 M NaOH/0.4 M NaF (1 : 1). Soils were from a cabbage cultivation with annual burning of weeds, a Pinus reforestation, a secondary forest, and a primary

APA, Harvard, Vancouver, ISO, and other styles

33

Liu, Xiangyu, Ling Li, Zibing Chen, Xianfa Duan, Yongjian Yu, and Lizhuan Sun. "Curing behavior, thermal, and mechanical properties of N,N′-(4,4′-diphenylmethane)bismaleimide/2,2′-diallylbisphenol A/3-allyl-5,5-dimethylhydantoin resin system." High Performance Polymers 32, no. 6 (2019): 631–44. http://dx.doi.org/10.1177/0954008319894034.

Full text

Abstract:

The 3-allyl-5,5-dimethylhydantoin (ADMH) was synthesized and characterized by Fourier transform infrared spectroscopy, 1H-nuclear magnetic resonance (NMR), and 13C-NMR spectroscopy. Then, the ADMH was used to modify the N, N′-(4,4′-diphenylmethane)bismaleimide (BDM)/2,2′-diallylbisphenol A (DABPA) resin to obtain the BDM/DABPA/ADMH resin system (BDA). The curing behavior was investigated by non-isothermal differential scanning calorimetry and the activation energy ([Formula: see text]) was obtained by Kissinger and Ozawa models. The thermomechanical property was measured by dynamic mechanical

APA, Harvard, Vancouver, ISO, and other styles

34

Alders, David J. C., A. B. Johan Groeneveld, Frans J. J. de Kanter, and Johannes H. G. M. van Beek. "Myocardial O2 consumption in porcine left ventricle is heterogeneously distributed in parallel to heterogeneous O2 delivery." American Journal of Physiology-Heart and Circulatory Physiology 287, no. 3 (2004): H1353—H1361. http://dx.doi.org/10.1152/ajpheart.00338.2003.

Full text

Abstract:

Myocardial blood flow is unevenly distributed, but the cause of this heterogeneity is unknown. Heterogeneous blood flow may reflect heterogeneity of oxygen demand. The aim of the present study was to assess the relation between oxygen consumption and blood flow in small tissue regions in porcine left ventricle. In seven male, anesthetized, open-chest pigs, local oxygen consumption was quantitated by computational model analysis of the incorporation of 13C in glutamate via the tricarboxylic acid cycle during timed infusion of [13C]acetate into the left anterior descending coronary artery. Blood

APA, Harvard, Vancouver, ISO, and other styles

35

Lewandowski, E. D., M. V. Chari, R. Roberts, and D. L. Johnston. "NMR studies of beta-oxidation and short-chain fatty acid metabolism during recovery of reperfused hearts." American Journal of Physiology-Heart and Circulatory Physiology 261, no. 2 (1991): H354—H363. http://dx.doi.org/10.1152/ajpheart.1991.261.2.h354.

Full text

Abstract:

The effects of beta-oxidation on the contractile recovery and metabolic activity of postischemic (10 min) rabbit hearts were examined during reperfusion with the short-chain fatty acid butyrate. Hearts received either 13C-enriched butyrate or acetate to evaluate metabolic targeting with 13C nuclear magnetic resonance (NMR) spectroscopy. Acetate and butyrate supported similar contractility (rate of pressure development, dP/dt) and 31P-NMR-detected, high-energy phosphate (HEP) levels during normal perfusion. In postischemic hearts, butyrate sustained a greater percentage of preischemic dP/dt (83

APA, Harvard, Vancouver, ISO, and other styles

36

Agger, Peter, Janus Adler Hyldebrandt, Esben Søvsø Szocska Hansen, et al. "Magnetic resonance hyperpolarization imaging detects early myocardial dysfunction in a porcine model of right ventricular heart failure." European Heart Journal - Cardiovascular Imaging 21, no. 1 (2019): 93–101. http://dx.doi.org/10.1093/ehjci/jez074.

Full text

Abstract:

Abstract Aims Early detection of heart failure is important for timely treatment. During the development of heart failure, adaptive intracellular metabolic processes that evolve prior to macro-anatomic remodelling, could provide an early signal of impending failure. We hypothesized that metabolic imaging with hyperpolarized magnetic resonance would detect the early development of heart failure before conventional echocardiography could reveal cardiac dysfunction. Methods and results Five 8.5 kg piglets were subjected to pulmonary banding and subsequently examined by [1-13C]pyruvate hyperpolari

APA, Harvard, Vancouver, ISO, and other styles

37

Datta, R. N., A. H. M. Schotman, A. J. M. Weber, et al. "Biscitraconimides as Anti-Reversion Agents for Diene Rubbers: Spectroscopic Studies on Citraconimide-Squalene Adducts." Rubber Chemistry and Technology 70, no. 1 (1997): 129–45. http://dx.doi.org/10.5254/1.3538413.

Full text

Abstract:

Abstract The mechanism of anti-reversion activity of biscitraconimides (BCI) during rubber vulcanization has been investigated. Biscitraconimides form crosslinks by reaction with chain modifications which are formed during the reversion process. These additional crosslinks compensate for the sulfidic crosslinks that are lost during the reversion. To allow structural assignments of the adducts formed between rubber and citraconimides, squalene has been used as a simple model system in combination with the currently used additives and sulphur. The products were identified as Diels—Alder adducts

APA, Harvard, Vancouver, ISO, and other styles

38

Kherroub, Djamal Eddine, Mohammed Belbachir, and Saad Lamouri. "A new approach for the polymerization of tetraphenyltetramethylcyclotetrasiloxane by an environmentally friendly catalyst called Maghnite-H+." Green Processing and Synthesis 7, no. 4 (2018): 296–305. http://dx.doi.org/10.1515/gps-2017-0033.

Full text

Abstract:

Abstract This work is devoted to the study of the cationic ring opening polymerization of tetraphenyltetramethylcyclotetrasiloxane (D4Ph,Me), using a solid green catalyst prepared by the activation of a natural clay by sulfuric acid (Maghnite-H+). This treatment leads to the spacing of the montmorillonite sheets due to the substitution of the existing interlayer cations by the protons of the acid. This consequence is clearly shown on the X-ray diffraction (XRD) spectrum. The polymerization reaction proceeded in bulk and under mild conditions. Various tests were carried out by changing the temp

APA, Harvard, Vancouver, ISO, and other styles

39

Bischoff, S., M. T. Schwarz, J. Siemens, L. Thieme, W. Wilcke, and B. Michalzik. "Properties of dissolved and total organic matter in throughfall, stemflow and forest floor leachate of Central European forests." Biogeosciences Discussions 11, no. 10 (2014): 15087–107. http://dx.doi.org/10.5194/bgd-11-15087-2014.

Full text

Abstract:

Abstract. For the first time, we investigated the composition of dissolved organic matter (DOM) compared to total OM (TOM, consisting of DOM and particulate OM, POM) in throughfall, stemflow and forest floor leachate of beech and spruce forests using solid state 13C nuclear magnetic resonance spectroscopy. We hypothesized that the composition and properties of OM in forest ecosystem water samples differed between DOM and TOM and between the two tree species. Under beech, a contribution of phyllosphere-derived fresh POM was echoed in structural differences. Compared with DOM, TOM exhibited high

APA, Harvard, Vancouver, ISO, and other styles

40

Tingaut, Philippe, Oliver Weigenand, Carsten Mai, Holger Militz, and Gilles Sèbe. "Chemical reaction of alkoxysilane molecules in wood modified with silanol groups." Holzforschung 60, no. 3 (2006): 271–77. http://dx.doi.org/10.1515/hf.2006.044.

Full text

Abstract:

Abstract Chemical reaction between silanol-modified wood and methyltrimethoxysilane (MTMS) was carried out using two different approaches with dibutyltin dilaurate (DBTDL) or ethylamine (EtNH2) as catalysts. Modifications were characterised by Fourier-transform infrared (FTIR) spectroscopy, as well as solid-state 13C and 29Si cross-polarisation with magic-angle spinning nuclear magnetic resonance (CP-MAS NMR) spectroscopy and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) analysis. Silanol-modified wood was obtained by carbamoylation reaction with 3-isocyanatopropyltriethoxysil

APA, Harvard, Vancouver, ISO, and other styles

41

Biagini, Giancarlo A., Peter S. McIntyre, Bland J. Finlay, and David Lloyd. "Carbohydrate and Amino Acid Fermentation in the Free-Living Primitive Protozoon Hexamita sp." Applied and Environmental Microbiology 64, no. 1 (1998): 203–7. http://dx.doi.org/10.1128/aem.64.1.203-207.1998.

Full text

Abstract:

ABSTRACT Hexamita sp. is an amitochondriate free-living diplomonad which inhabits O2-limited environments, such as the deep waters and sediments of lakes and marine basins.13C nuclear magnetic resonance spectroscopy reveals ethanol, lactate, acetate, and alanine as products of glucose fermentation under microaerobic conditions (23 to 34 μM O2). Propionic acid and butyric acid were also detected and are believed to be the result of fermentation of alternative substrates. Production of organic acids was greatest under microaerobic conditions (15 μM O2) and decreased under anaerobic (<0.25 μM

APA, Harvard, Vancouver, ISO, and other styles

42

Kansy, Dawid, Kornelia Bosowska, Krystyna Czaja, and Anna Poliwoda. "The Formation of Glycerol Oligomers with Two New Types of End Groups in the Presence of a Homogeneous Alkaline Catalyst." Polymers 11, no. 1 (2019): 144. http://dx.doi.org/10.3390/polym11010144.

Full text

Abstract:

The purpose of this work was to synthesize and characterize oligoglycerols with the chains of more than four repeating units. Those oligoglycerols may have some interesting applications, among others, as polyoxyalkylation starters. The glycerol oligomerization process was carried out during 12 h, at 230 °C, under the pressure of 0.4 bar, with the use of sodium carbonate as a homogeneous basic catalyst; various concentrations of the catalyst in the reaction medium were used. The reaction products were analyzed with the use of direct infusion electrospray ionization mass spectrometry (ESI-MS), n

APA, Harvard, Vancouver, ISO, and other styles

43

Chatham, J. C., and J. R. Forder. "Metabolic compartmentation of lactate in the glucose-perfused rat heart." American Journal of Physiology-Heart and Circulatory Physiology 270, no. 1 (1996): H224—H229. http://dx.doi.org/10.1152/ajpheart.1996.270.1.h224.

Full text

Abstract:

Several studies using exogenous pyruvate as substrate have suggested that there are separate intracellular pyruvate pools in cardiac cells. Such heterogeneity in intracellular pyruvate has important implications for our understanding of both oxidative and nonoxidative glucose metabolism. Because pyruvate is not a major substrate for the heart in vivo, we wished to determine if there was pyruvate compartmentation with glucose as substrate. Hearts were isolated from male Sprague-Dawley rats and retrogradely perfused (Langendorff) with a modified Krebs-Henseleit buffer containing [1-13C[glucose f

APA, Harvard, Vancouver, ISO, and other styles

44

Zhang, Kan, Yuqi Liu, Zhikun Shang, Corey Evans, and Shengfu Yang. "Effects of End-Caps on the Atropisomerization, Polymerization, and the Thermal Properties of ortho-Imide Functional Benzoxazines." Polymers 11, no. 3 (2019): 399. http://dx.doi.org/10.3390/polym11030399.

Full text

Abstract:

A new type of atropisomerism has recently been discovered in 1,3-benzoxazines, where the intramolecular repulsion between negatively charged oxygen atoms on the imide and the oxazine ring hinders the rotation about the C–N bond. The imide group offers a high degree of flexibility for functionalization, allowing a variety of functional groups to be attached, and producing different types of end-caps. In this work, the effects of end-caps on the atropisomerism, thermally activated polymerization of ortho-imide functional benzoxazines, and the associated properties of polybenzoxazines have been s

APA, Harvard, Vancouver, ISO, and other styles

45

Neves, Ana Rute, Ana Ramos, Helena Costa, et al. "Effect of Different NADH Oxidase Levels on Glucose Metabolism by Lactococcus lactis: Kinetics of Intracellular Metabolite Pools Determined by In Vivo Nuclear Magnetic Resonance." Applied and Environmental Microbiology 68, no. 12 (2002): 6332–42. http://dx.doi.org/10.1128/aem.68.12.6332-6342.2002.

Full text

Abstract:

ABSTRACT Three isogenic strains of Lactococcus lactis with different levels of H2O-forming NADH oxidase activity were used to study the effect of oxygen on glucose metabolism: the parent strain L. lactis MG1363, a NOX− strain harboring a deletion of the gene coding for H2O-forming NADH oxidase, and a NOX+ strain with the NADH oxidase activity enhanced by about 100-fold. A comprehensive description of the metabolic events was obtained by using 13C nuclear magnetic resonance in vivo. The most noticeable results of this study are as follows: (i) under aerobic conditions the level of fructose 1,6-

APA, Harvard, Vancouver, ISO, and other styles

46

Pastor Ramírez, Cándida, Sylvain Bernès, Samuel Hernández Anzaldo та Yasmi Reyes Ortega. "Structure and NMR properties of the dinuclear complex di-μ-azido-κ4 N 1:N 1-bis[(azido-κN)(pyridine-2-carboxamide-κ2 N 1,O)zinc(II)]". Acta Crystallographica Section E Crystallographic Communications 77, № 2 (2021): 111–16. http://dx.doi.org/10.1107/s2056989020016680.

Full text

Abstract:

The new diamagnetic complex, [Zn2(N3)4(C6H6N2O)2] or [Zn2(pca)2(μ1,1-N3)2(N3)2] was synthesized using pyridine-2-carboxamide (pca) and azido ligands, and characterized using various techniques: IR spectroscopy and single-crystal X-ray diffraction in the solid state, and nuclear magnetic resonance (NMR) in solution. The molecule is placed on an inversion centre in space group P\overline{1}. The pca ligand chelates the metal centre via the pyridine N atom and the carbonyl O atom. One azido ligand bridges the two symmetry-related Zn2+ cations in the end-on coordination mode, while the other indep

APA, Harvard, Vancouver, ISO, and other styles

47

Pastor Ramírez, Cándida, Sylvain Bernès, Samuel Hernández Anzaldo та Yasmi Reyes Ortega. "Structure and NMR properties of the dinuclear complex di-μ-azido-κ4 N 1:N 1-bis[(azido-κN)(pyridine-2-carboxamide-κ2 N 1,O)zinc(II)]". Acta Crystallographica Section E Crystallographic Communications 77, № 2 (2021): 111–16. http://dx.doi.org/10.1107/s2056989020016680.

Full text

Abstract:

The new diamagnetic complex, [Zn2(N3)4(C6H6N2O)2] or [Zn2(pca)2(μ1,1-N3)2(N3)2] was synthesized using pyridine-2-carboxamide (pca) and azido ligands, and characterized using various techniques: IR spectroscopy and single-crystal X-ray diffraction in the solid state, and nuclear magnetic resonance (NMR) in solution. The molecule is placed on an inversion centre in space group P\overline{1}. The pca ligand chelates the metal centre via the pyridine N atom and the carbonyl O atom. One azido ligand bridges the two symmetry-related Zn2+ cations in the end-on coordination mode, while the other indep

APA, Harvard, Vancouver, ISO, and other styles

48

Sepperer, Thomas, Primož Šket, Alexander Petutschnigg, and Nicola Hüsing. "Tannin-Furanic Foams Formed My Mechanical Agitation: Influence of Surfactant and Ingredient Ratios." Polymers 13, no. 18 (2021): 3058. http://dx.doi.org/10.3390/polym13183058.

Full text

Abstract:

With increasing demand of alternatives to oil-based lightweight materials, the development of tannin-based foams is getting more and more attention. In this paper, an alternative to traditionally used solvent-evaporation in the production of tannin-foams is presented. Mixing the tannin-furanic resin with different amounts of ionic and non-ionic surfactants at high agitational speed allows for the formation of highly porous, mechanically stable tannin-foams. Investigations on the influence of surfactant type and ingredient ratios on the foaming behavior and properties of the final foams were co

APA, Harvard, Vancouver, ISO, and other styles

49

Van Geel-Schutten, G. H., E. J. Faber, E. Smit, et al. "Biochemical and Structural Characterization of the Glucan and Fructan Exopolysaccharides Synthesized by theLactobacillus reuteri Wild-Type Strain and by Mutant Strains." Applied and Environmental Microbiology 65, no. 7 (1999): 3008–14. http://dx.doi.org/10.1128/aem.65.7.3008-3014.1999.

Full text

Abstract:

ABSTRACT Lactobacillus reuteri LB 121 cells growing on sucrose synthesize large amounts of a glucan (d-glucose) and a fructan (d-fructose) with molecular masses of 3,500 and 150 kDa, respectively. Methylation studies and 13C or1H nuclear magnetic resonance analysis showed that the glucan has a unique structure consisting of terminal, 4-substituted, 6-substituted, and 4,6-disubstituted α-glucose in a molar ratio of 1.1:2.7:1.5:1.0. The fructan was identified as a (2→6)-β-d-fructofuranan or levan, the first example of levan synthesis by a Lactobacillus species. Strain LB 121 possesses glucansucr

APA, Harvard, Vancouver, ISO, and other styles

50

Coffinet, Sarah, Travis B. Meador, Lukas Mühlena, et al. "Structural elucidation and environmental distributions of butanetriol and pentanetriol dialkyl glycerol tetraethers (BDGTs and PDGTs)." Biogeosciences 17, no. 2 (2020): 317–30. http://dx.doi.org/10.5194/bg-17-317-2020.

Full text

Abstract:

Abstract. Butanetriol and pentanetriol dialkyl glycerol tetraethers (BDGTs and PDGTs) are membrane lipids, recently discovered in sedimentary environments and in the methanogenic archaeon Methanomassiliicoccus luminyensis. They possess an unusual structure, which challenges fundamental assumptions in lipid biochemistry. Indeed, they bear a butanetriol or a pentanetriol backbone instead of a glycerol at one end of their core structure. In this study, we unambiguously located the additional methyl group of the BDGT compound on the C3 carbon of the lipid backbone via high-field nuclear magnetic r

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!