Bibliographies thématiques / Proton and phosphorus Nuclear Magnetic Resonance / Articles de revues
Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Proton and phosphorus Nuclear Magnetic Resonance.

Articles de revues sur le sujet « Proton and phosphorus Nuclear Magnetic Resonance »

Auteur : Grafiati
Publié le 9 mars 2023
Mis à jour le 10 mars 2023

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres

Choisissez une source :

Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Proton and phosphorus Nuclear Magnetic Resonance ».

À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.

Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.

Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.

1

Ghasemi, Mir Majid, et Manouchehr Bahrami. « MEMS NUCLEAR MAGNETIC RESONANCE MICROCOIL ». Biomedical Engineering : Applications, Basis and Communications 29, no 02 (avril 2017) : 1750009. http://dx.doi.org/10.4015/s1016237217500090.

Texte intégral
Résumé :
NMR is one of the important analytic tools which is used to obtain certain information such as metabolic concentrations in neural or muscular tissues. In some other important applications such as proton decoupling, it is necessary to design NMR transmitters/receivers capable of operating at multiple frequencies, while maintaining a good performance at each frequency. In this work, a new nuclear magnetic resonance (NMR) receiver microcoil based on MEMS technology is proposed. The designed structure uses MEMS microswitches with low contact resistance and NMR-based actuation mechanism. The proposed device can detect carbon (13C), proton (1H), and phosphorus (31p) nucleus with larmor frequencies of 96.36[Formula: see text]MHz, 383[Formula: see text]MHz, and 155.11[Formula: see text]MHz at 9 T magnetic field, respectively. The designed microcoil achieves three important goals: (1) Getting high SNR, high Q and high filling factor which are key parameters in NMR performance, by changing number of turns. (2) Turning into the array of microcoils to obtain better SNR. (3) Turning into two or three microcoils inside of each other for simultaneous detection. The MEMS microswitch in this paper uses static magnetic field of the NMR for its operation ([Formula: see text]T) which simplifies the switch mechanism. This switch is small (150[Formula: see text][Formula: see text]m[Formula: see text][Formula: see text][Formula: see text]50[Formula: see text][Formula: see text]m[Formula: see text][Formula: see text][Formula: see text]6[Formula: see text][Formula: see text]m), scattering parameters of 43.2[Formula: see text]db isolation and 0.0059 insertion loss and maximum displacement of 2.03[Formula: see text][Formula: see text]m due to the magnetostatic actuation. In this work, the models and investigations are conducted using finite element simulations in COMSOL Multiphysics. The switch scattering parameters are obtained by HFSS 12.0.
Styles APA, Harvard, Vancouver, ISO, etc.
2

Sugiyama, Hiroshi, Yasuhisa Senda et Jun-ichi Ishiyama. « Proton, carbon, and phosphorus nuclear magnetic resonance and conformational studies on phosphate esters ». Journal of the Chemical Society, Perkin Transactions 2, no 3 (1987) : 391. http://dx.doi.org/10.1039/p29870000391.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
3

Stuhrmann, Heinrich B. « Small-angle scattering and its interplay with crystallography, contrast variation in SAXS and SANS ». Acta Crystallographica Section A Foundations of Crystallography 64, no 1 (21 décembre 2007) : 181–91. http://dx.doi.org/10.1107/s0108767307046569.

Texte intégral
Résumé :
Methods of contrast variation are tools that are essential in macromolecular structure research. Anomalous dispersion of X-ray diffraction is widely used in protein crystallography. Recent attempts to extend this method to native resonant labels like sulfur and phosphorus are promising. Substitution of hydrogen isotopes is central to biological applications of neutron scattering. Proton spin polarization considerably enhances an existing contrast prepared by isotopic substitution. Concepts and methods of nuclear magnetic resonance (NMR) become an important ingredient in neutron scattering from dynamically polarized targets.
Styles APA, Harvard, Vancouver, ISO, etc.
4

Khan, Shahid A., I. Jane Cox, Andrew V. Thillainayagam, Devinder S. Bansi, Howard C. Thomas et Simon D. Taylor-Robinson. « Proton and phosphorus-31 nuclear magnetic resonance spectroscopy of human bile in hepatopancreaticobiliary cancer ». European Journal of Gastroenterology & ; Hepatology 17, no 7 (juillet 2005) : 733–38. http://dx.doi.org/10.1097/00042737-200507000-00007.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
5

Rivera, Debra. « Emerging Role for 7T MRI and Metabolic Imaging for Pancreatic and Liver Cancer ». Metabolites 12, no 5 (30 avril 2022) : 409. http://dx.doi.org/10.3390/metabo12050409.

Texte intégral
Résumé :
Advances in magnet technologies have led to next generation 7T magnetic resonance scanners which can fit in the footprint and price point of conventional hospital scanners (1.5–3T). It is therefore worth asking if there is a role for 7T magnetic resonance imaging and spectroscopy for the treatment of solid tumor cancers. Herein, we survey the medical literature to evaluate the unmet clinical needs for patients with pancreatic and hepatic cancer, and the potential of ultra-high field proton imaging and phosphorus spectroscopy to fulfil those needs. We draw on clinical literature, preclinical data, nuclear magnetic resonance spectroscopic data of human derived samples, and the efforts to date with 7T imaging and phosphorus spectroscopy. At 7T, the imaging capabilities approach histological resolution. The spectral and spatial resolution enhancements at high field for phospholipid spectroscopy have the potential to reduce the number of exploratory surgeries due to tumor boundaries undefined at conventional field strengths. Phosphorus metabolic imaging at 7T magnetic field strength, is already a mainstay in preclinical models for molecular phenotyping, energetic status evaluation, dosimetry, and assessing treatment response for both pancreatic and liver cancers. Metabolic imaging of primary tumors and lymph nodes may provide powerful metrics to aid staging and treatment response. As tumor tissues contain extreme levels of phospholipid metabolites compared to the background signal, even spectroscopic volumes containing less than 50% tumor can be detected and/or monitored. Phosphorus spectroscopy allows non-invasive pH measurements, indicating hypoxia, as a predictor of patients likely to recur. We conclude that 7T multiparametric approaches that include metabolic imaging with phosphorus spectroscopy have the potential to meet the unmet needs of non-invasive location-specific treatment monitoring, lymph node staging, and the reduction in unnecessary surgeries for patients undergoing resections for pancreatic cancer. There is also potential for the use of 7T phosphorous spectra for the phenotyping of tumor subtypes and even early diagnosis (<2 mL). Whether or not 7T can be used for all patients within the next decade, the technology is likely to speed up the translation of new therapeutics.
Styles APA, Harvard, Vancouver, ISO, etc.
6

Brauer, Manfred, et Steven Locke. « Proton magnetic resonance imaging and phosphorus-31 magnetic resonance spectroscopy studies of bromobenzene-induced liver damage in the rat ». Magnetic Resonance Imaging 10, no 2 (janvier 1992) : 257–67. http://dx.doi.org/10.1016/0730-725x(92)90485-i.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
7

van der Kemp, Wybe J. M., Bertine L. Stehouwer, Vincent O. Boer, Peter R. Luijten, Dennis W. J. Klomp et Jannie P. Wijnen. « Proton and phosphorus magnetic resonance spectroscopy of the healthy human breast at 7 T ». NMR in Biomedicine 30, no 2 (28 décembre 2016) : e3684. http://dx.doi.org/10.1002/nbm.3684.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
8

Yan, Yanan, et Bing Liang. « Flame-retardant behavior and mechanism of a DOPO-based phosphorus–nitrogen flame retardant in epoxy resin ». High Performance Polymers 31, no 8 (10 octobre 2018) : 885–92. http://dx.doi.org/10.1177/0954008318805794.

Texte intégral
Résumé :
A novel flame-retardant additive, 6,6′,6″-((1,3,5-triazine-2,4,6 triyl) tris (azanediyl)) tris (dibenzo[c,e][1,2]oxaphosphinine 6-oxide) (DOPO-M), was synthesized from melamine and 9,10-dihy-dro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO). The structure of DOPO-M was characterized by Fourier transform infrared (FTIR) spectroscopy, proton (1H) and phosphorous (31P) nuclear magnetic resonance (NMR) spectroscopies, and electrospray ionization mass spectroscopy (ESI-MS). DOPO-M was blended into epoxy resin (EP) to prepare flame-retardant EPs. The flame-retardant and thermal properties of EPs cured with triethylenetetramine (TETA) were investigated by thermogravimetric analysis (TGA), the UL-94 test, and the limiting oxygen index (LOI) test. The results revealed that the epoxy thermosets exhibited excellent flame retardancy and passed the V-0 rating of the UL-94 test with an LOI of 29.3% when the phosphorus content was 2.57 wt%. The scanning electron microscopy (SEM) results showed that DOPO-M in the EP/TETA system obviously accelerated the formation of a stronger, phosphorus-rich sealing char layer to improve the flame-retardant properties of the matrix during combustion.
Styles APA, Harvard, Vancouver, ISO, etc.
9

Harrison, Philip G., et Thakor Kikabhai. « Proton and phosphorus-31 nuclear magnetic resonance study of zinc(II)O,O′-dialkyl dithiophosphates in solution ». J. Chem. Soc., Dalton Trans., no 4 (1987) : 807–14. http://dx.doi.org/10.1039/dt9870000807.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
10

Théberge, Jean, Yousef Al-Semaan, J. Eric Jensen, Peter C. Williamson, Richard W. J. Neufeld, Ravi S. Menon, Betsy Schaefer, Maria Densmore et Dick J. Drost. « Comparative study of proton and phosphorus magnetic resonance spectroscopy in schizophrenia at 4 Tesla ». Psychiatry Research : Neuroimaging 132, no 1 (novembre 2004) : 33–39. http://dx.doi.org/10.1016/j.pscychresns.2004.08.001.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
11

Chida, K., H. Otani, H. Saito, T. Nagasaka, Y. Kagaya, M. Kohzuki, M. Zuguchi et K. Shirato. « Feasibility of rapid‐sequence 31p magnetic resonance spectroscopy in cardiac patients ». Acta Radiologica 46, no 4 (juillet 2005) : 386–90. http://dx.doi.org/10.1080/02841850510021283.

Texte intégral
Résumé :
Purpose: To determine the clinical feasibility of rapid‐sequence phosphorus‐31 magnetic resonance spectroscopy (31P ‐MRS) of the heart with cardiac patients using a 1.5T clinical MR system. Material and Methods: Twenty cardiac patients, i.e. dilated cardiomyopathy (DCM) 13 cases, hypertrophic cardiomyopathy (HCM) 3 cases, hypertensive heart diseases (HHD) 3 cases, and aortic regurgitation (AR) 1 case were examined using rapid cardiac 31P‐MRS. Complete three‐dimensional localization was performed using a two‐dimensional phosphorus chemical‐shift imaging sequence in combination with 30‐mm axial slice‐selective excitation. The rapid‐sequence 31P‐MRS procedure was phase encoded in arrays of 8×8 steps with an average of 4 acquisitions. The total examination time, including proton imaging and shimming, for the rapid cardiac 31P‐MRS procedure, ranged from 10 to 15 min, depending on the heart rate. Student's t test was used to compare creatine phosphate (PCr)/adenosine triphosphate (ATP) ratios from the cardiac patients with those of the control subjects ( n = 13). Results: The myocardial PCr/ATP ratio obtained by rapid 31P‐MRS was significantly lower ( P<0.001) in DCM patients (1.82±0.33, mean±SD), and in patients with global myocardial dysfunction (combined data for 20 patients: 1.89±0.32) than in normal volunteers (2.96±0.59). These results are similar to previous studies. Conclusion: Rapid‐sequence 31P‐MRS may be a valid diagnostic tool for patients with cardiac disease.
Styles APA, Harvard, Vancouver, ISO, etc.
12

Laurie, Olive, John Oakes, Jeff W. Rockliffe et Edward G. Smith. « Phosphorus and proton nuclear magnetic resonance studies of transition-metal complexes of triphosphate and pyrophosphate in aqueous solution ». Journal of the Chemical Society, Faraday Transactions 1 : Physical Chemistry in Condensed Phases 82, no 10 (1986) : 3149. http://dx.doi.org/10.1039/f19868203149.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
13

Schaefer, Ted, Rudy Sebastian et Frank E. Hruska. « 1H nuclear magnetic resonance and molecular orbital studies of the internal rotational potential and electron delocalization in triphenylphosphine ». Canadian Journal of Chemistry 71, no 5 (1 mai 1993) : 639–43. http://dx.doi.org/10.1139/v93-085.

Texte intégral
Résumé :
The 1H nuclear magnetic resonance spectral parameters are reported for triphenylphosphine as solutions in CS2/C6D12 and acetone-d6 at 300 K. The internal rotational potential opposing torsion about the P—C bond is computed by AMI and STO-3G MO methods. The computed potentials are used to calculate the average shielding of the para protons caused by the diamagnetic anisotropies of the neighbouring phenyl groups. The results are used to estimate the degree of electron delocalization from the lone pair on phosphorus. The extent of delocalization depends on the internal motions and comparisons are made with phenylphosphine. The maximum possible screening of the para protons in phenylphosphine is calculated as 0.19 ppm for a conformation in which the lone pair on phosphorus is oriented perpendicular to the aromatic plane. The intramolecular rotational potentials then yield 0.029 ppm as the shielding of the para protons in triphenylphosphine due to electron delocalization, just as found for the CS2/C6D12 solution after correction for diamagnetic anisotropy fields.
Styles APA, Harvard, Vancouver, ISO, etc.
14

Vallée, Jean-Paul, François Lazeyras, H. Dirk Sostman, Stephen R. Smith, David W. Butterly, Charles E. Spritzer et H. Cecil Charles. « Proton-decoupled phosphorus-31 magnetic resonance spectroscopy in the evaluation of native and well-functioning transplanted kidneys ». Academic Radiology 3, no 12 (décembre 1996) : 1030–37. http://dx.doi.org/10.1016/s1076-6332(96)80040-7.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
15

Russu, Irina M., Shing Shing Wu, Keith A. Bupp, Nancy T. Ho et Chien Ho. « Proton and phosphorus-31 nuclear magnetic resonance investigation of the interaction between 2,3-diphosphoglycerate and human normal adult hemoglobin ». Biochemistry 29, no 15 (17 avril 1990) : 3785–92. http://dx.doi.org/10.1021/bi00467a027.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
16

Barthwal, Ritu, et Zia Tariq. « Molecular Recognition of Parallel G-quadruplex [d-(TTGGGGT)]4 Containing Tetrahymena Telomeric DNA Sequence by Anticancer Drug Daunomycin : NMR-Based Structure and Thermal Stability ». Molecules 23, no 9 (5 septembre 2018) : 2266. http://dx.doi.org/10.3390/molecules23092266.

Texte intégral
Résumé :
The anticancer drug daunomycin exerts its influence by multiple strategies of action to interfere with gene functioning. Besides inhibiting DNA/RNA synthesis and topoisomerase-II, it affects the functional pathway of telomere maintenance by the telomerase enzyme. We present evidence of the binding of daunomycin to parallel-stranded tetramolecular [d-(TTGGGGT)]4 guanine (G)-quadruplex DNA comprising telomeric DNA from Tetrahymena thermophilia by surface plasmon resonance and Diffusion Ordered SpectroscopY (DOSY). Circular Dichroism (CD) spectra show the disruption of daunomycin dimers, suggesting the end-stacking and groove-binding of the daunomycin monomer. Proton and phosphorus-31 Nuclear Magnetic Resonance (NMR) spectroscopy show a sequence-specific interaction and a clear proof of absence of intercalation of the daunomycin chromophore between base quartets or stacking between G-quadruplexes. Restrained molecular dynamics simulations using observed short interproton distance contacts depict interaction at the molecular level. The interactions involving ring A and daunosamine protons, the stacking of an aromatic ring of daunomycin with a terminal G6 quartet by displacing the T7 base, and external groove-binding close to the T1–T2 bases lead to the thermal stabilization of 15 °C, which is likely to inhibit the association of telomerase with telomeres. The findings have implications in the structure-based designing of anthracycline drugs as potent telomerase inhibitors.
Styles APA, Harvard, Vancouver, ISO, etc.
17

Devlin, Cathy C., et Charles M. Grisham. « Proton and phosphorus-31 nuclear magnetic resonance and kinetic studies of the active site structure of chloroplast CF1 ATP synthase ». Biochemistry 29, no 26 (juillet 1990) : 6192–203. http://dx.doi.org/10.1021/bi00478a012.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
18

WAKITA, Misako, Yoshihiro KURODA et Terumichi NAKAGAWA. « Interactions between Local Anesthetic Dibucaine and Pig Erythrocyte Membranes as Studied by Proton and Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy. » CHEMICAL & ; PHARMACEUTICAL BULLETIN 40, no 6 (1992) : 1361–65. http://dx.doi.org/10.1248/cpb.40.1361.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
19

Micallef, Duncan, Liana Vella-Zarb et Ulrich Baisch. « Exploring the Structural Chemistry of Pyrophosphoramides : N,N′,N″,N‴-Tetraisopropylpyrophosphoramide ». Chemistry 3, no 1 (28 janvier 2021) : 149–63. http://dx.doi.org/10.3390/chemistry3010013.

Texte intégral
Résumé :
N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.
Styles APA, Harvard, Vancouver, ISO, etc.
20

Moseley, M. E., M. F. Wendland, D. K. Darnell et C. A. Gooding. « Metabolic and anatomic development of the chick embryo as studied by phosphorus-31 magnetic resonance spectroscopy and proton MRI ». Pediatric Radiology 19, no 6-7 (juillet 1989) : 400–405. http://dx.doi.org/10.1007/bf02387637.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
21

Clark, H. C., V. K. Jain, R. C. Mehrotra, B. P. Singh, G. Srivastava et T. Birchall. « Tin-119, phosphorus-31, carbon-13 and proton nuclear magnetic resonance and Mössbauer studies of mono-, di- and tri-organotin(IV) dialkyldithiophosphates ». Journal of Organometallic Chemistry 279, no 3 (janvier 1985) : 385–94. http://dx.doi.org/10.1016/0022-328x(85)87036-4.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
22

Barbarella, Giovanna, Massimo Luigi Capobianco, Luisa Tondelli et Vitaliano Tugnoli. « 15N and 13C nuclear magnetic resonance of deoxydinucleotide monophosphates. II. Protonation of the homo dimers deoxycytidylyl-(3′,5′)-deoxycytidine, thymidylyl-(3′,5′)-thymidine, and deoxyadenylyl-(3′,5′)-deoxyadenosine in dimethyl sulfoxide ». Canadian Journal of Chemistry 68, no 11 (1 novembre 1990) : 2033–38. http://dx.doi.org/10.1139/v90-311.

Texte intégral
Résumé :
The preferential protonation sites of the homo dimers deoxycytidylyl-(3′,5′)-deoxycytidine, thymidylyl-(3′,5′)-thymidine, and deoxyadenylyl-(3′,5′)-deoxyadenosine were established by nitrogen-15 and carbon-13 NMR in dimethyl sulfoxide, in the presence of varying amounts of CF3COOH. The nitrogen-15 NMR data show that in d(CpC) the capability of the two N3 nitrogens to accept the proton is slightly different. In d(TpT) and d(ApA) the protonation of the phosphate group leads to significant variations of the chemical shift of the carbons adjacent to phosphorus. Keywords: deoxydinucleotides, protonation, 15N and 13C NMR.
Styles APA, Harvard, Vancouver, ISO, etc.
23

Zakian, Kristen L., Jason A. Koutcher, Sandeep Malhotra, Howard Thaler, William Jarnagin, Lawrence Schwartz et Yuman Fong. « Liver regeneration in humans is characterized by significant changes in cellular phosphorus metabolism : Assessment using proton-decoupled31P- magnetic resonance spectroscopic imaging ». Magnetic Resonance in Medicine 54, no 2 (2005) : 264–71. http://dx.doi.org/10.1002/mrm.20560.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
24

Wang, Yongzhen, Yanchao Yuan, Ying Zhao, Shumei Liu et Jianqing Zhao. « Flame–retarded epoxy resin with high glass transition temperature cured by DOPO-containing H-benzimidazole ». High Performance Polymers 29, no 1 (28 juillet 2016) : 94–103. http://dx.doi.org/10.1177/0954008316628967.

Texte intégral
Résumé :
A halogen-free flame retardant of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-containing H-benzimidazole (DHBI) was synthesized and subsequently used as co-curing agent of 4,4′-diamino-diphenylmethane for diglycidyl ether of bisphenol-A. The structure of DHBI was characterized by Fourier transform infrared (FTIR) spectroscopy, proton, carbon 13 and phosphorus-31 nuclear magnetic resonance, and mass spectroscopy. A series of cured epoxy resins (EPs) were prepared and their flame retardancy, thermal stability, flexibility, and dielectric properties were investigated. The resulting cured EP (EP-10) with 7.45 wt% of DHBI successfully achieved UL 94 V-0 rate with limited oxygen index of 35.6% and without dropping phenomenon. Compared with the cured pristine EP (EP-00), the glass transition temperature of EP-10 was increased by 6.9°C, accompanied with an enhancement of flexible strength by 13.1 MPa and a decrement of dielectric constant by 0.3 at the testing frequency of 1 MHz.
Styles APA, Harvard, Vancouver, ISO, etc.
25

Yang, Shuang, Yefa Hu et Qiaoxin Zhang. « Synthesis of a phosphorus–nitrogen-containing flame retardant and its application in epoxy resin ». High Performance Polymers 31, no 2 (5 février 2018) : 186–96. http://dx.doi.org/10.1177/0954008318756496.

Texte intégral
Résumé :
In this article, a phosphorus–nitrogen-containing flame retardant (DOPO-T) was successfully synthesized by nucleophilic substitution reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and cyanuric chloride. The chemical structure of DOPO-T was characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (NMR) and phosphorous-31 NMR, and elemental analysis. DOPO-T was then blended with diglycidyl ether of bisphenol-A to prepare flame-retardant epoxy resins. Thermal properties, flame retardancy, and combustion behavior of the cured epoxy resins were evaluated by differential scanning calorimetry, thermogravimetric analysis, limited oxygen index (LOI) measurement, UL94 vertical burning test, and cone calorimeter test. The results indicated that the glass transition temperature ( Tg) and temperature at 5% weight loss of epoxy resin (EP)/DOPO-T thermosets were gradually decreased with the increasing content of DOPO-T. DOPO-T catalyzed the decomposition of EP matrix in advance. The flame-retardant performance of EP thermosets was significantly enhanced with the addition of DOPO-T. EP/DOPO-T-0.9 sample had an LOI value of 36.2% and achieved UL94 V-1 rating. In addition, the average of heat release rate, peak of heat release rate, average of effective heat of combustion, and total heat release (THR) of EP/DOPO-T-0.9 sample were decreased by 32%, 48%, 23%, and 31%, respectively, compared with the neat EP sample. Impressively, EP/DOPO-T thermosets acquired excellent flame retardancy under low loading of flame retardant.
Styles APA, Harvard, Vancouver, ISO, etc.
26

Matwiyoff, Nicholas A. « NMR imaging and spectroscopy of tissue at high resolution : problems and prospects ». Proceedings, annual meeting, Electron Microscopy Society of America 44 (août 1986) : 110–11. http://dx.doi.org/10.1017/s0424820100142190.

Texte intégral
Résumé :
When the nuclei of atoms like hydrogen (1H), carbon (13C), phosphorus (31P), and sodium (23Na) are subjected to a static magnetic field, they can be induced to emit electromagnetic radiation. This phenomenon, called nuclear magnetic resonance (NMR), was first demonstrated experimentally by the research groups of Bloch and Purcell in 1946. Because the spectrum of the radiation emitted depends on the type of nucleus and its chemical environment, NMR spectroscopy was rapidly exploited by chemists and has become a major tool for the investigation of molecular structure and the analysis of complex mixtures. More recently the NMR response of living systems subjected to known gradients of a static magnetic field has been exploited in medicine to construct images of the concentration and environment of hydrogen (protons) in the water and fat of soft tissues in the body.
Styles APA, Harvard, Vancouver, ISO, etc.
27

Lancelot, G., U. Asseline, N. T. Thuong et C. Helene. « Proton and phosphorus nuclear magnetic resonance studies of an oligothymidylate covalently linked to an acridine derivative and of its binding to complementary sequences ». Biochemistry 24, no 10 (7 mai 1985) : 2521–29. http://dx.doi.org/10.1021/bi00331a019.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
28

Kinsey, S., et W. Ellington. « 1H- and 31P-nuclear magnetic resonance studies of l-lactate transport in isolated muscle fibers from the spiny lobster Panulirus argus ». Journal of Experimental Biology 199, no 10 (1 octobre 1996) : 2225–34. http://dx.doi.org/10.1242/jeb.199.10.2225.

Texte intégral
Résumé :
Proton (1H) and phosphorus (31P) nuclear magnetic resonance (NMR) spectroscopy were used to investigate the mode of transport of l-lactate across the plasma membranes of the abdominal extensor muscles of the spiny lobster Panulirus argus. Individual fibers or bundles of 2&shy;3 fibers were superfused in a dual-tuned (1H, 31P) microsolenoid NMR probe. 1H-NMR spectra were diffusion-weighted, which eliminated the signal contribution of the fast-flowing extracellular lactate but retained that of intracellular lactate. Well-resolved intracellular lactate signals could be acquired at 15 s intervals, permitting estimation of initial velocities (Vi) of influx and efflux during loading/unloading of muscle fibers. 31P-NMR spectra were acquired to assess cellular energy status and intracellular pH. Transport results showed that Vi values for influx and efflux were a linear function of total lactate concentration, displaying no saturation effects. The rate of lactate influx was enhanced by increasing the concentration of the free acid by altering the superfusate pH. Vi values for influx and efflux of d- and l-lactate were identical. Finally, traditional inhibitors of monocarboxylate and/or anion transport had no effect on influx/efflux of lactate from these cells. The above results strongly suggest that the primary mode of lactate transport is by passive diffusion. These cells appear to lack a monocarboxylate transporter, which may be related to the apparent absence of organ-specific compartmentation of lactate metabolism in crustaceans.
Styles APA, Harvard, Vancouver, ISO, etc.
29

Boulanger, Yvan, Pascale Legault, Alberto Tejedor, Patrick Vinay et Yves Theriault. « Biochemical characterization and osmolytes in papillary collecting ducts from pig and dog kidneys ». Canadian Journal of Physiology and Pharmacology 66, no 10 (1 octobre 1988) : 1282–90. http://dx.doi.org/10.1139/y88-210.

Texte intégral
Résumé :
Papillary collecting duct tubules were prepared in gram quantities from the papillae of dog and pig kidneys. Measurements of substrate and oxygen utilizations by these tubules under both aerobic and anaerobic conditions showed the potential for both glycolysis and oxidative phosphorylation. Oxygen is not necessary to maintain a normal adenosine 5′-triphosphate concentration, but oxidative phosphorylation contributes to more than 65% of the metabolism under aerobic conditions in the two species. Both phosphorus-31 and proton nuclear magnetic resonance spectra recorded from extracts of dog cortex, red medulla, and papilla showed a clear gradient from cortex to papilla for osmolytes, such as glycerophosphorylcholine, sorbitol, inositol, betaine, and sugar phosphates. Other molecules identified in the spectra included glucose, sorbitol, mannitol, lactate, glutamine, alanine, threonine, and adenosine 5′-triphosphate. Conventional biochemical measurements supported these findings. An increase in osmolality from 300 to 600 mosmol/kg H2O for 120 min did not increase the glycerophosphorylcholine and sorbitol concentrations of dog papillary collecting ducts in vitro, but a small effect of a 24-h dehydration was detected in vivo.
Styles APA, Harvard, Vancouver, ISO, etc.
30

Vu, Cuong Manh, Van-Huy Nguyen et Quang-Vu Bach. « Phosphorous-jointed epoxidized soybean oil and rice husk-based silica as the novel additives for improvement mechanical and flame retardant of epoxy resin ». Journal of Fire Sciences 38, no 1 (janvier 2020) : 3–27. http://dx.doi.org/10.1177/0734904119900990.

Texte intégral
Résumé :
The combined effects of phosphorous-jointed epoxidized soybean oil and rice husk–based silica on the flammability and mechanical properties of epoxy resin were examined in detail. The chemical structures of the epoxidized soybean oil, phosphorous-jointed epoxidized soybean oil, and rice husk–based silica were confirmed using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Many characteristics of the obtained composite materials were examined, such as the tensile properties, impact strength, flexural strength, critical stress intensity factor (KIC), dynamic mechanical analysis, and flammability. The incorporation of both 10 phr phosphorous-jointed epoxidized soybean oil and 20 phr rice husk–based silica into the epoxy resin yielded the optimum values of the flexural strength, tensile strength, impact strength, and KIC, with increases of 87.78%, 67.23%, 109.34%, and 111.32%, respectively, compared with pristine samples. The limiting oxygen index increased from 23.1% to 29.3%, the peak heat-release rate decreased by up to 37.2%, and the sample satisfied the UL94 V-0 rating.
Styles APA, Harvard, Vancouver, ISO, etc.
31

Rango, Mario, Andrea Arighi, Cristiana Bonifati, Roberto Del Bo, Giacomo Comi et Nereo Bresolin. « The Brain is Hypothermic in Patients with Mitochondrial Diseases ». Journal of Cerebral Blood Flow & ; Metabolism 34, no 5 (12 mars 2014) : 915–20. http://dx.doi.org/10.1038/jcbfm.2014.38.

Texte intégral
Résumé :
We sought to study brain temperature in patients with mitochondrial diseases in different functional states compared with healthy participants. Brain temperature and mitochondrial function were monitored in the visual cortex and the centrum semiovale at rest and during and after visual stimulation in seven individuals with mitochondrial diseases ( n = 5 with mitochondrial DNA mutations and n = 2 with nuclear DNA mutations) and in 14 age- and sex-matched healthy control participants using a combined approach of visual stimulation, proton magnetic resonance spectroscopy (MRS), and phosphorus MRS. Brain temperature in control participants exhibited small changes during visual stimulation and a consistent increase, together with an increase in high-energy phosphate content, after visual stimulation. Brain temperature was persistently lower in individuals with mitochondrial diseases than in healthy participants at rest, during activation, and during recovery, without significant changes from one state to another and with a decrease in the high-energy phosphate content. The lowest brain temperature was observed in the patient with the most deranged mitochondrial function. In patients with mitochondrial diseases, the brain is hypothermic because of malfunctioning oxidative phosphorylation. Neuronal activity is reduced at rest, during physiologic brain stimulation, and after stimulation.
Styles APA, Harvard, Vancouver, ISO, etc.
32

Deutsch, W. Francis, et Robert A. Shaw. « Phosphorus–nitrogen compounds. Part 55. The reactions of 2,2,4,4-tetrachloro-6,6-diphenylcyclotriphosphazatriene with aliphatic difunctional alcohols, amines, and aminoalcohols. Proton and phosphorus-31 nuclear magnetic resonance spectroscopic studies of the products ». J. Chem. Soc., Dalton Trans., no 7 (1988) : 1757–63. http://dx.doi.org/10.1039/dt9880001757.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
33

Shaw, Robert A., et David A. Watkins. « Phosphorus–nitrogen compounds. Part 56. The solution synthesis of some trans-1,3-dialkyl-2,4-diphenyl-2,4-dithiocyclodi-λ5-phosphazanes and their proton, carbon-13, and phosphorus-31 nuclear magnetic resonance spectra ». J. Chem. Soc., Dalton Trans., no 10 (1988) : 2591–96. http://dx.doi.org/10.1039/dt9880002591.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
34

MORIKAWA, SHIGEHIRO, TOSHIRO INUBUSHI et KOUICHI KITO. « Lactate and pH Mapping in Calf Muscles of Rats during Ischemia/Reperfusion Assessed by In Vivo Proton and Phosphorus Magnetic Resonance Chemical Shift Imaging ». Investigative Radiology 29, no 2 (février 1994) : 217–23. http://dx.doi.org/10.1097/00004424-199402000-00018.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
35

Gonen, Oded, Afsaneh Mohebbi, Radka Stoyanova et Truman R. Brown. « In vivo phosphorus polarization transfer and decoupling from protons in three-dimensional localized nuclear magnetic resonance spectroscopy of human brain ». Magnetic Resonance in Medicine 37, no 2 (février 1997) : 301–6. http://dx.doi.org/10.1002/mrm.1910370228.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
36

Grace, A. A., H. L. Kirschenlohr, J. C. Metcalfe, G. A. Smith, P. L. Weissberg, E. J. Cragoe et J. I. Vandenberg. « Regulation of intracellular pH in the perfused heart by external HCO3- and Na(+)-H+ exchange ». American Journal of Physiology-Heart and Circulatory Physiology 265, no 1 (1 juillet 1993) : H289—H298. http://dx.doi.org/10.1152/ajpheart.1993.265.1.h289.

Texte intégral
Résumé :
Both Na(+)-dependent HCO3- influx and the Na(+)-H+ antiport have been shown to contribute to recovery from intracellular acidosis in avian and mammalian cardiac tissue. We have investigated the participation of these mechanisms in the recovery of intracellular pH (pHi) after an acid load in the Langendorff-perfused ferret heart. pHi was measured from the phosphorus-31 nuclear magnetic resonance chemical shift of 2-deoxy-D-glucose 6-phosphate. Basal pHi was higher in HCO(3-)-buffered solution (7.05 +/- 0.01; n = 8) than in nominally HCO(3-)-free N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) solution (6.98 +/- 0.02; n = 9). Addition of 5-(N-ethyl-N-isopropyl)amiloride (EIPA) caused a significant fall in pHi in HEPES solution (6.91 +/- 0.02; n = 5) but not in HCO3- solution (7.02 +/- 0.02; n = 5). Intrinsic intracellular buffering capacity in 0 Na(+)-HEPES solution was 37 +/- 2 mmol/l (n = 4), and additional buffering due to HCO(3-)-CO2 was approximately 13 mmol/l in HCO3- solution. After an intracellular acidosis induced by an NH4Cl prepulse, the proton efflux rate (JH) at pHi 6.90 was 0.5 +/- 0.2 nmol.l-1.min-1 (n = 14) in HEPES solution and 1.2 +/- 0.4 mmol.l-1.min-1 (n = 13) in HCO3- solution. The addition of 1 microM EIPA effectively blocked proton efflux in HEPES solution (JH < 0.1 mmol.l-1.min-1; n = 8), whereas it slowed pHi recovery in HCO3- solution (JH = 0.6 +/- 0.2 mmol.l-1.min-1; n = 9). There was no recovery of pHi in Na(+)-free HCO3- solution (JH < 0.1 mmol.l-1.min-1; n = 3). The Na(+)-H+ antiport and a mechanism requiring both external Na+ and HCO3- each contribute approximately 50% to proton efflux at pHi 6.90 during the recovery from intracellular acidosis in the isolated perfused mammalian heart.
Styles APA, Harvard, Vancouver, ISO, etc.
37

Ghannoum, Oula, Matthew J. Paul, Jane L. Ward, Michael H. Beale, Delia-Irina Corol et Jann P. Conroy. « The sensitivity of photosynthesis to phosphorus deficiency differs between C3 and C4 tropical grasses ». Functional Plant Biology 35, no 3 (2008) : 213. http://dx.doi.org/10.1071/fp07256.

Texte intégral
Résumé :
Phosphorus (P) is an important determinant of plant productivity, particularly in the tropical grasslands of Australia, which contain both C3 and C4 species. Few studies have compared the responses of such species to P deficiency. Previous work led us to hypothesise that C3 photosynthesis and the three subtypes of C4 photosynthesis have different sensitivities to P deficiency. To examine their dynamic response to P deficiency in more detail, four taxonomically related tropical grasses (Panicum laxum (C3) and Panicum coloratum, Cenchrus ciliaris and Panicum maximum belonging to the C4 subtypes NAD-ME, NADP-ME and PCK, respectively) were grown under contrasting P supplies, including P withdrawal from the growing medium. Changes in photosynthesis and growth were compared with leaf carbohydrate contents and metabolic fingerprints obtained using high-resolution proton nuclear magnetic resonance (1H-NMR). The response of CO2 assimilation rates to leaf contents of inorganic phosphate ([Pi]) was linear in the C3 grass, but asymptotic for the three C4 grasses. Relative growth rate was affected most by low P in the C3 species and was correlated with the leaf content of glucose 6-phosphate more than with carbohydrates. Principal component analysis of the 1H-NMR spectra revealed distinctive profiles of carbohydrates and amino acids for the four species. Overall, the data showed that photosynthesis of the three C4 subtypes behaved similarly. Compared with the C3 counterpart, photosynthesis of the three C4 grasses had a higher P use efficiency and lower Pi requirement, and responded to a narrower range of [Pi]. Although each of the four grass species showed distinctive 1H-NMR fingerprints, there were no differences in response that could be attributed to the C4 subtypes.
Styles APA, Harvard, Vancouver, ISO, etc.
38

Vestergaard-Poulsen, P., C. Thomsen, T. Sinkjaer et O. Henriksen. « Simultaneous 31P-NMR spectroscopy and EMG in exercising and recovering human skeletal muscle : a correlation study ». Journal of Applied Physiology 79, no 5 (1 novembre 1995) : 1469–78. http://dx.doi.org/10.1152/jappl.1995.79.5.1469.

Texte intégral
Résumé :
A large number of studies have shown amplitude and spectral changes of the electromyogram during exercise, leading to several theories of how these changes might be related to the underlying metabolic changes. The amplitude and spectral changes are generally interpreted as changes in motor unit recruitment and a reduction of the muscle fiber conduction velocity due to proton or lactate accumulation. This study focuses on the causality of spectral changes of the surface electromyogram and proton or lactate accumulation and how the changes in motor unit recruitment are related to the metabolic status of the muscle. Simultaneous 31P-nuclear magnetic resonance spectroscopy and surface electromyography were performed during sustained static exercise and recovery in healthy volunteers and a patient with McArdle's disease. A clear dissociation between the median power frequency of the surface electromyogram and pH was seen in the healthy volunteers during recovery and during exercise in the patient with McArdle's disease. The results indicate that proton or lactate accumulation is not primarily responsible for the spectral changes of the surface electromyogram as previously suggested. The motor unit recruitment (as judged by the root mean square of the surface electromyogram) increased hyperbolically during the submaximal static exercise, with decreasing phosphocreatine-to-P(i) ratio reaching maximum at 0.6 (exhaustion), and seems to constitute a consistent metabolic limit to the exercise. The increased myoelectrical activity seen after exercise is not caused by an incomplete recovery of phosphorous metabolism, pH, or lactate but could probably be an impairment of the excitation-contraction coupling.
Styles APA, Harvard, Vancouver, ISO, etc.
39

Vann, Willie F., Dayle A. Daines, Andrew S. Murkin, Martin E. Tanner, Donald O. Chaffin, Craig E. Rubens, Justine Vionnet et Richard P. Silver. « The NeuC Protein of Escherichia coli K1 Is a UDP N-Acetylglucosamine 2-Epimerase ». Journal of Bacteriology 186, no 3 (1 février 2004) : 706–12. http://dx.doi.org/10.1128/jb.186.3.706-712.2004.

Texte intégral
Résumé :
ABSTRACT The K1 capsule is an essential virulence determinant of Escherichia coli strains that cause meningitis in neonates. Biosynthesis and transport of the capsule, an α-2,8-linked polymer of sialic acid, are encoded by the 17-kb kps gene cluster. We deleted neuC, a K1 gene implicated in sialic acid synthesis, from the chromosome of EV36, a K-12-K1 hybrid, by allelic exchange. Exogenously added sialic acid restored capsule expression to the deletion strain (ΔneuC), confirming that NeuC is necessary for sialic acid synthesis. The deduced amino acid sequence of NeuC showed similarities to those of UDP-N-acetylglucosamine (GlcNAc) 2-epimerases from both prokaryotes and eukaryotes. The NeuC homologue from serotype III Streptococcus agalactiae complements ΔneuC. We cloned the neuC gene into an intein expression vector to facilitate purification. We demonstrated by paper chromatography that the purified neuC gene product catalyzed the formation of [2-14C]acetamidoglucal and [N-14C]acetylmannosamine (ManNAc) from UDP-[14C]GlcNAc. The formation of reaction intermediate 2-acetamidoglucal with the concomitant release of UDP was confirmed by proton and phosphorus nuclear magnetic resonance spectroscopy. NeuC could not use GlcNAc as a substrate. These data suggest that neuC encodes an epimerase that catalyzes the formation of ManNAc from UDP-GlcNAc via a 2-acetamidoglucal intermediate. The unexpected release of the glucal intermediate and the extremely low rate of ManNAc formation likely were a result of the in vitro assay conditions, in which a key regulatory molecule or protein was absent.
Styles APA, Harvard, Vancouver, ISO, etc.
40

Adams, G. R., J. M. Foley et R. A. Meyer. « Muscle buffer capacity estimated from pH changes during rest-to-work transitions ». Journal of Applied Physiology 69, no 3 (1 septembre 1990) : 968–72. http://dx.doi.org/10.1152/jappl.1990.69.3.968.

Texte intégral
Résumé :
Gated phosphorus nuclear magnetic resonance (31P-NMR) spectra were acquired after 5 or 9 s of 5-Hz stimulation in rat and cat skeletal muscles, respectively. Net phosphocreatine (PCr) hydrolysis was associated with an intracellular alkalinization of 0.08 +/- 0.01 and 0.05 +/- 0.003 pH units in isolated perfused cat biceps and soleus, respectively, and 0.12 +/- 0.02 in the superficial predominantly fast-twitch white portion of gastrocnemius of anesthetized rats. The net change in [H+] expected from PCr hydrolysis was calculated, and apparent buffer capacity (beta) in intact muscles was calculated from beta = delta [H+]/delta pH. The beta of the same muscle types was also estimated from titration of muscle homogenates between pH 6.0 and 8.0. The contribution of Pi to total beta of the homogenates was subtracted to ascertain the non-Pi beta for each muscle. The non-Pi beta values were added to the actual amount of Pi present in the stimulated muscles to calculate a predicted beta at pH 7. The apparent beta calculated from PCr and pH changes in intact muscles and the predicted beta from homogenate titrations were in good agreement (38 +/- 9 vs. 38 slykes in cat biceps, 21 +/- 7 vs. 30 in cat soleus, and 30 +/- 6 vs. 27 in rat gastrocnemius). The results indicate that changes in pH during the first few seconds of contraction can be entirely accounted for by proton consumption via net PCr hydrolysis.
Styles APA, Harvard, Vancouver, ISO, etc.
41

Machado, Irlaine, Isabel Hsieh, Veronica Calado, Thomas Chapin et Hatsuo Ishida. « Nacre-Mimetic Green Flame Retardant : Ultra-High Nanofiller Content, Thin Nanocomposite as an Effective Flame Retardant ». Polymers 12, no 10 (14 octobre 2020) : 2351. http://dx.doi.org/10.3390/polym12102351.

Texte intégral
Résumé :
A nacre-mimetic brick-and-mortar structure was used to develop a new flame-retardant technology. A second biomimetic approach was utilized to develop a non-flammable elastomeric benzoxazine for use as a polymer matrix that effectively adheres to the hydrophilic laponite nanofiller. A combination of laponite and benzoxazine is used to apply an ultra-high nanofiller content, thin nanocomposite coating on a polyurethane foam. The technology used is made environmentally friendly by eliminating the need to add any undesirable flame retardants, such as phosphorus additives or halogenated compounds. The very-thin coating on the polyurethane foam (PUF) is obtained through a single dip-coating. The structure of the polymer has been confirmed by proton nuclear magnetic resonance spectroscopy (1H NMR) and Fourier transform infrared spectroscopy (FTIR). The flammability of the polymer and nanocomposite was evaluated by heat release capacity using microscale combustion calorimetry (MCC). A material with heat release capacity (HRC) lower than 100 J/Kg is considered non-ignitable. The nanocomposite developed exhibits HRC of 22 J/Kg, which is well within the classification of a non-ignitable material. The cone calorimeter test was also used to investigate the flame retardancy of the nanocomposite’s thin film on polyurethane foam. This test confirms that the second peak of the heat release rate (HRR) decreased 62% or completely disappeared for the coated PUF with different loadings. Compression tests show an increase in the modulus of the PUF by 88% for the 4 wt% coating concentration. Upon repeated modulus tests, the rigidity decreases, approaching the modulus of the uncoated PUF. However, the effect of this repeated mechanical loading does not significantly affect the flame retarding performance.
Styles APA, Harvard, Vancouver, ISO, etc.
42

Meyer, R. A., T. R. Brown, B. L. Krilowicz et M. J. Kushmerick. « Phosphagen and intracellular pH changes during contraction of creatine-depleted rat muscle ». American Journal of Physiology-Cell Physiology 250, no 2 (1 février 1986) : C264—C274. http://dx.doi.org/10.1152/ajpcell.1986.250.2.c264.

Texte intégral
Résumé :
To evaluate the functional role of phosphocreatine (PCr) and creatine in muscle metabolism, these compounds were depleted by feeding rats the creatine analogue, beta-guanidinopropionate (beta-GPA, 2% of diet). Changes in phosphate metabolites and intracellular pH were monitored in gastrocnemius muscle in situ by phosphorus nuclear magnetic resonance (31P-NMR) at 162 MHz using the surface coil technique. After 3 mo of feeding, 25 mumol/g of phosphorylated beta-GPA (beta-GPAP) had accumulated, and PCr, creatine, and ATP levels were reduced to 6, 17, and 56%, respectively, compared with muscles of control animals. In resting muscle, there was no measurable exchange of phosphate between beta-GPAP and ATP by the NMR saturation transfer method. During muscle stimulation at 1 and 5 Hz, the maximum net rate of beta-GPAP hydrolysis was 10% that of PCr in control muscles, so that after 150 s inorganic phosphate had increased to less than 50% of the level attained in control muscles. At both rates, peak twitch force declined toward a steady state more rapidly in beta-GPA-loaded muscles, but after 100 s force was either not different (1 Hz) or significantly greater (5 Hz) in the beta-GPA-fed animals. Intracellular pH initially decreased more rapidly during stimulation and recovered more rapidly afterward in the beta-GPA-loaded muscles compared with controls. This difference could be explained by the difference in expected proton consumption due to net PCr hydrolysis. However, despite buffering by PCr hydrolysis, pH ultimately decreased more in control muscle (6.1 vs. 6.3 for 5 Hz), indicating greater acid accumulation compared with beta-GPA-loaded muscles. In the superficial, predominantly fast-twitch glycolytic section of muscles clamp-frozen after 5-Hz stimulation for 150 s, lactate accumulation was twofold greater in controls. The results indicate that PCr is not essential for steady-state energy production but that the phosphate from PCr hydrolysis may be important for maximum activation of glycogenolysis and/or glycolysis.
Styles APA, Harvard, Vancouver, ISO, etc.
43

Szurkowska, Katarzyna, Agata Drobniewska et Joanna Kolmas. « Dual Doping of Silicon and Manganese in Hydroxyapatites : Physicochemical Properties and Preliminary Biological Studies ». Materials 12, no 16 (12 août 2019) : 2566. http://dx.doi.org/10.3390/ma12162566.

Texte intégral
Résumé :
Silicated hydroxyapatite powders enriched with small amounts of manganese (Mn2+) cations were synthesized via two different methods: precipitation in aqueous solution and the solid-state method. The source of Mn2+ ions was manganese acetate, while silicon was incorporated using two different reagents: silicon acetate and sodium metasilicate. Powder X-ray diffraction (PXRD) analysis showed that the powders obtained via the precipitation method consisted of single-phase nanocrystalline hydroxyapatite. In contrast, samples obtained via the solid-state method were heterogenous and contaminated with other phases, (i.e., calcium oxide, calcium hydroxide, and silicocarnotite) arising during thermal treatment. The transmission electron microscope (TEM) images showed powders obtained via the precipitation method were nanosized and elongated, while solid-state synthesis produced spherical microcrystals. The phase identification was complemented by Fourier transform infrared spectroscopy (FTIR). An in-depth analysis via solid-state nuclear magnetic resonance (ssNMR) was carried out, using phosphorus 31P single-pulse Bloch decay (BD) (31P BD) and cross-polarization (CP) experiments from protons to silicon-29 nuclei (1H → 29Si CP). The elemental measurements carried out using wavelength-dispersive X-ray fluorescence (WD-XRF) showed that the efficiency of introducing manganese and silicon ions was between 45% and 95%, depending on the synthesis method and the reagents. Preliminary biological tests on the bacteria Allivibrio fisheri (Microtox®) and the protozoan Spirostomum ambiguum (Spirotox) showed no toxic effect in any of the samples. The obtained materials may find potential application in regenerative medicine, bone implantology, and orthopedics as bone substitutes or implant coatings.
Styles APA, Harvard, Vancouver, ISO, etc.
44

Liang, Bing, Jiao Lv, Gang Wang et Tsubaki Noritatsu. « Synthesis and characterisation of the halogen-free flame retardant and mechanical performance of the retardant epoxies resin ». Pigment & ; Resin Technology 46, no 3 (2 mai 2017) : 172–80. http://dx.doi.org/10.1108/prt-02-2016-0021.

Texte intégral
Résumé :
Purpose The purpose of this paper is to prepare a novel halogen-free intumescent flame retardant (IFR) BHPPODC (benzene hydroquinone phosphorous oxy dichloride cyanuric chloride) for application to epoxy resin (EP) and study their mechanical and flame-retardant performance. Design/methodology/approach The IFR was synthesised by phenylphosphonic dichloride, hydroquinone and cyanuric chloride via solvent reaction, and the structure was fully characterised by proton nuclear magnetic resonance (1H-NMR), mass spectrometry (MS) and Fourier transform infrared (FT-IR) spectroscopy. The thermal stability, mechanical and flame properties and morphology of the char layer of the flame-retardant EP was investigated by using thermogravimetric analysis (TGA), tensile and Charpy impact tests, limiting oxygen index (LOI) and vertical burning test (UL-94) and scanning electron microscopy (SEM). Findings Results of the LOI indicated that the halogen-free flame retardant as an additive exhibits very good flame-retardant effects. The results showed that the addition of IFR improved the flame resistance properties of epoxies resin composites, and the residual char ratio at 800°C significantly increased. Research limitations/implications The IFR can be prepared successfully and can improve the flame-retardant performance. Practical implications This contribution can provide a high flame retardant performance and has minimal impact on the mechanical performance of the BHPPODC/EP composition. Originality/value This study showed that flame-retardant BHPPODC has an effective flame effect under optimal conditions. When the 12 Wt.% IFR was added to the EP, the LOI was 29.1 and the UL-94 rank can reach V-0 rank, the tensile strength was 83.86 MPa and the impact strength was 8.82 kJ/m2.
Styles APA, Harvard, Vancouver, ISO, etc.
45

SAPEGA, ALEXANDER A., DAVID P. SOKOLOW, THOMAS J. GRAHAM et BRITTON CHANCE. « Phosphorus nuclear magnetic resonance ». Medicine & ; Science in Sports & ; Exercise 19, no 4 (août 1987) : 410???420. http://dx.doi.org/10.1249/00005768-198708000-00015.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
46

SAPEGA, ALEXANDER A., DAVID P. SOKOLOW, THOMAS J. GRAHAM et BRITTON CHANCE. « Phosphorus nuclear magnetic resonance ». Medicine & ; Science in Sports & ; Exercise 25, no 6 (juin 1993) : 656???666. http://dx.doi.org/10.1249/00005768-199306000-00002.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
47

Ahmed, Nehal S., Hamdy S. Abdel-Hameed, Ahmed F. El-Kafrawy et Amal M. Nassar. « Synthesis and evaluation of ashless detergent/dispersant additives for lubricating engine oil ». Industrial Lubrication and Tribology 67, no 6 (14 septembre 2015) : 622–29. http://dx.doi.org/10.1108/ilt-05-2015-0065.

Texte intégral
Résumé :
Purpose – The aim of this paper is to solve the problem of carbonaceous deposits in automotive engines by preparing different ashless detergent/dispersant additives based on propylene oxide (PO) and different amines. Carbonaceous deposits in automotive engines are the major problems associated with oil aging. Efficient detergents and dispersants have been used to solve this problem, particularly in lubricating oils. Design/methodology/approach – The structures of the prepared compounds were confirmed using Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H-NMR) and gel permeation chromatography (GPC) for determination of molecular weight. This was followed by the evaluation of the prepared compounds such as detergent/dispersant and antioxidants additives for lubricating engine oil using several techniques such as variation of viscosity ratio, change in total acid number, optical density using infrared techniques, spot method, determination of sludge and determination the potential detergent dispersant efficiency (PDDE). Findings – All the prepared compounds were found to be soluble in lubricating oil. The efficiency of the prepared compounds such as antioxidant and detergent/dispersant additives for lubricating oil was investigated. It was found that the additives have excellent power of dispersion, detergency and the most efficient additives such as antioxidant those prepared by using n,n-dimethyloctadecylamine (NDOA) and di-n-butyl dithio phosphoric acid. Practical implications – The paper includes preparation of new compounds from the reaction of propoxylated amines and different organic acids and evaluates them as detergent/dispersant and antioxidants additives by using several techniques. Originality/value – This paper fulfils an identified need to prepare new compounds from the reaction of propoxylated amines and different organic acids and evaluates them as additives by using different methods. All were found to have better efficiency as compared with commercial additives.
Styles APA, Harvard, Vancouver, ISO, etc.
48

Drenth, W., et D. Rosenberg. « Proton magnetic resonance spectra of some acetylenic phosphorus compounds ». Recueil des Travaux Chimiques des Pays-Bas 86, no 1 (2 septembre 2010) : 26–30. http://dx.doi.org/10.1002/recl.19670860104.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
49

Greiner, Jack V., Stephen J. Kopp et Thomas Glonek. « Phosphorus nuclear magnetic resonance and ocular metabolism ». Survey of Ophthalmology 30, no 3 (novembre 1985) : 189–202. http://dx.doi.org/10.1016/0039-6257(85)90063-3.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
50

Felber, Stephan R., Roger Pycha, Martina Hummer, Franz T. Aicher et W. Wolfgang Fleischhacker. « Localized proton and phosphorus magnetic resonance spectroscopy following electroconvulsive therapy ». Biological Psychiatry 33, no 8-9 (avril 1993) : 651–54. http://dx.doi.org/10.1016/0006-3223(93)90106-n.

Texte intégral
Styles APA, Harvard, Vancouver, ISO, etc.
Vous pouvez également être intéressé par les bibliographies sur le sujet « Proton and phosphorus Nuclear Magnetic Resonance » pour d’autres types de sources :
Thèses Livres
Nous offrons des réductions sur tous les plans premium pour les auteurs dont les œuvres sont incluses dans des sélections littéraires thématiques. Contactez-nous pour obtenir un code promo unique!

Vers la bibliographie