Anomalous properties of supercooled water. Heat capacity, expansivity, and proton magnetic resonance chemical shift from 0 to -38%

1973 ◽  
Vol 77 (26) ◽  
pp. 3092-3099 ◽  
Author(s):  
C. A. Angell ◽  
J. Shuppert ◽  
J. C. Tucker
Keyword(s):  
Heat Capacity ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Proton Magnetic Resonance ◽  
Supercooled Water

A STUDY OF TAUTOMERISM IN CYCLIC β-DIKETONES BY PROTON MAGNETIC RESONANCE

1965 ◽  
Vol 43 (11) ◽  
pp. 3057-3062 ◽  
Author(s):  
Natsuko Cyr ◽  
Leonard W. Reeves
Keyword(s):  
Magnetic Resonance ◽  
Chemical Shift ◽  
Proton Magnetic Resonance ◽  
Enthalpy Change ◽  
Enol Form ◽  
Proton Resonance ◽  
Kcal Mole ◽  
Intensity Measurements ◽  
Acetonitrile Solutions ◽  
Monomer Form

The keto–enol equilibrium of cyclohexane-1,3-dione in chloroform is best interpreted from proton resonance measurements as[Formula: see text]K1 and K2 may be separately determined from chemical shift measurements of the enol-OH proton and intensity measurements of peaks assigned to keto and enol forms. K1 and K2 are satisfactorily independent of concentrations except in very dilute solutions where intensity measurements become unreliable. The overall equilibrium constant K = K1 × K22 can be obtained for the same molecule in acetonitrile solutions where the enol monomer form is in very low concentration. 5,5′-Dimethylcyclohexane-1,3-dione in chloroform has less enol form than the unsubstituted molecule. The enthalpy change associated with 'K' for cyclohexane-1,3-dione in chloroform is 2.05 ± 0.5 kcal mole−1.

scholarly journals ORYX-MRSI: A Fully-Automated Open-Source Software for Three-Dimensional Proton Magnetic Resonance Spectroscopic Imaging Data Analysis

2021 ◽  
Author(s):  
Sevim Cengiz ◽  
Muhammed Yildirim ◽  
Abdullah Bas ◽  
Esin Ozturk-Isik
Keyword(s):  
Data Analysis ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Open Source ◽  
Proton Magnetic Resonance ◽  
Spectroscopic Imaging ◽  
Brain Atlas ◽  
Magnetic Resonance Spectroscopic Imaging ◽  
Spectral Quality ◽  
Chemical Shift Artifact

Proton magnetic resonance spectroscopic imaging (1H-MRSI) provides noninvasive evaluation of brain metabolism. However, there are some limitations of 1H-MRSI preventing its wider use in the clinics, including the spectral quality issues, partial volume effect and chemical shift artifact. Additionally, it is necessary to create metabolite maps for analyzing spectral data along with other MRI modalities. In this study, a MATLAB-based open-source data analysis software for 3D 1H-MRSI, called Oryx-MRSI, which includes modules for visualization of raw 1H-MRSI data and LCModel outputs, chemical shift correction, tissue fraction calculation, metabolite map production, and registration onto standard MNI152 brain atlas while providing automatic spectral quality control, is presented. Oryx-MRSI implements region of interest analysis at brain parcellations defined on MNI152 brain atlas. All generated metabolite maps are stored in NIfTI format. Oryx-MRSI is publicly available at https://github.com/sevimcengiz/Oryx-MRSI along with six example datasets.

Proton Magnetic Resonance Chemical Shift Imaging ( 1 H CSI)-Directed Stereotactic Biopsy

2001 ◽  
Vol 143 (1) ◽  
pp. 45-50 ◽  
Author(s):  
B.-C. Son ◽  
M.-C. Kim ◽  
B.-G. Choi ◽  
E.-N. Kim ◽  
H.-M. Baik ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Chemical Shift ◽  
Proton Magnetic Resonance ◽  
Stereotactic Biopsy ◽  
Chemical Shift Imaging

Proton Magnetic Resonance Spectra of Some Substituted 2-Acylamino-3-arylamino-1,4-naphthoquinones

1976 ◽  
Vol 31 (2) ◽  
pp. 261-263 ◽  
Author(s):  
N. L. Agarwal ◽  
R. L. Mttal
Keyword(s):  
Magnetic Resonance ◽  
Chemical Shift ◽  
Proton Magnetic Resonance ◽  
Substitution Pattern ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of a number of substituted 2-acylamino-3-arylamino-1,4-naphthoquinones have been measured and discussed. The effect of various substitution pattern and hetero atoms on the chemical shift values of N-acylmethyl protons have been studied and explained.

Das Protonenresonanzspektrum von orientiertem Benzol in nematisch-kristallinflüssiger Lösung

1965 ◽  
Vol 20 (4) ◽  
pp. 572-580 ◽  
Author(s):  
Alfred Saupe
Keyword(s):  
Magnetic Resonance ◽  
Chemical Shift ◽  
Proton Magnetic Resonance ◽  
Resonance Spectrum ◽  
Proton Magnetic Resonance Spectrum ◽  
Coupling Constants ◽  
Scalar Coupling ◽  
Small Temperature ◽  
Theoretical Methods ◽  
Experimental Errors

The proton magnetic resonance spectrum of benzene oriented in a nematic solution is calculated using group theoretical methods. The calculations agree within experimental errors with the spectrum of benzene observed in a nematic solution of 4.4′-di-n-hexyloxy-azoxy-benzene. By an improvement of the temperature homogenity in the sample it was possible to obtain linewidths of only about 5 cps for all lines independent of the splitting. It is confirmed that the signs of the scalar coupling constants between ortho and meta protonpairs are positive. A small temperature dependence of the chemical shift of the benzene protons was found in the nematic solution. It is due to the dependence of the average orientation on the temperature.

scholarly journals Hypothalamic Myo-Inositol and Glucose concentrations, mood symptoms and fatigue in depression: a 3 Tesla chemical-shift-imaging in vivo proton magnetic resonance spectroscopy study

2020 ◽  
Author(s):  
Bruno Pedraz-Petrozzi ◽  
Carlo Blecker ◽  
Gebhard Sammer
Keyword(s):  
Magnetic Resonance ◽  
Chemical Shift ◽  
Glucose Metabolism ◽  
Proton Magnetic Resonance ◽  
Proton Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Impaired Glucose Metabolism ◽  
Mood Symptoms ◽  
Glial Dysfunction

Abstract Background: Many studies have confirmed altered brain Myo-Inositol (mIns) and Glucose (Glc) concentrations in depression. Alterations in the mIns-concentrations may represent a glial dysfunction and are associated mostly with depression symptoms. In comparison, alterations in the Glc-concentrations could represent impaired glucose metabolism. Despite this information, studies that assess these metabolites in the hypothalamus are missing. Therefore, this study aims to investigate mIns- and Glc-concentrations in the hypothalamus of participants with depression concerning mood symptoms and fatigue.Methods: We performed an in vivo proton magnetic resonance spectroscopy – chemical shift imaging of the hypothalamus in 49 participants (25 with depression diagnosis or DE, 24 healthy controls or HC), evaluating mIns- and Glc-concentrations. Concerning information about symptoms, we recollected information on depression symptomatology (BDI-FSTOT) and fatigue (FIS-D). For statistical analysis, we run generalized linear models by using the Poisson regression model with count data.Results: The results showed reduced hypothalamic mIns-concentration for every DE participant with higher FIS-D and higher BDI-FSTOT values (OR = 0.022; p < 0.001; CI95 [0.004 to 0.09]). Besides, the results showed increased hypothalamic Glc-concentration for every participant of the DE group and with higher BDI-FSTOT values (OR = 4.827; p = 0.002; CI95 [1.826 to 13.749]).Conclusions: These results provide initial evidence of a glial dysfunction and impaired glucose metabolism in the hypothalamus associated with mood symptoms and fatigue. Future studies are needed to confirm these pathophysiologic mechanisms.

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