Cellular water and proton relaxation times of Thai rice kernels during grain development and storage

The sonographic appearance of a hematoma may be affected by various factors, including the age of the hematoma. The effect of mechanical motion on the echogenicity and histologic appearance, and on the proton relaxation times T1 and T2 of blood clots, was studied in vitro for up to 21 days. All clots were of similar echogenicity and microscopic appearance during the first 2 days. The minimally disturbed clots were sonolucent from day 4 onwards, whereas moderate mechanical disturbance changed the microscopic structure of the blood clots and caused them to retain their echogenicity. Proton relaxation times T1 and T2 of both minimally disturbed and vigorously manipulated blood samples showed a rapid shortening of T1 and a less marked decrease of T2 between days 1 and 4, which was independent of mechanical motion. The ultrasonic appearance reflected the histologic appearance but not necessarily the age of the clot. The magnetic resonance (MR) parameters T1 and to a lesser extent T2 accurately reflected the age of the clot during the first 6 days. Although relatively gentle motion caused a large change in the ultrasonic appearance of the clots, vigorous shaking did not affect the magnetic resonance appearance of human blood clots.

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Temperature dependence of proton relaxation times in vitro

Magnetic Resonance Imaging ◽

10.1016/0730-725x(87)90020-8 ◽

1987 ◽

Vol 5 (3) ◽

pp. 189-199 ◽

Cited By ~ 85

Author(s):

T.R. Nelson ◽

S.M. Tung

Keyword(s):

Temperature Dependence ◽

Relaxation Times ◽

Proton Relaxation

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NMR Investigation of the Copper(II)-Ciprofloxacin System

Metal-Based Drugs ◽

10.1155/mbd.1999.1 ◽

1999 ◽

Vol 6 (1) ◽

pp. 1-4 ◽

Cited By ~ 3

Author(s):

Iztok Turel ◽

Janez Košmrlj ◽

Bjørn Andersen ◽

Einar Sletten

Keyword(s):

Acidic Medium ◽

Acidic Solution ◽

Relaxation Times ◽

Ring System ◽

Proton Relaxation ◽

X Ray ◽

Ph Values ◽

Nmr Study ◽

Terminal Nitrogen Atom ◽

Titration Data

A proton NMR study was performed on the copper(ll)-ciprofloxacin system. The proton relaxation times (T1) were determined from the titration data in acidic and basic media. In acidic medium the H5 signal is dramatically affected and it is assumed that copper is bonded to the quinolone through carbonyl and one of the carboxyl oxygens. Such bonding is in agreement with the X-ray literature data for the complex [Cu(cf)2]Cl2.6H2O isolated from the slightly acidic solution. There are additional significant changes in T1 of H3′ and H5′ atoms which suggest that the terminal nitrogen atom of the piperazine ring system-N4′ also interacts with copper in the basic conditions. Thus it is plausible that more than one species are present in the solution at high pH values.

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Modification of 4 Mhz N.M.R. Water Proton Relaxation Times in Very High Diluted Aqueous Solutions

Signals and Images ◽

10.1007/978-94-011-5804-6_8 ◽

1997 ◽

pp. 95-110 ◽

Cited By ~ 6

Author(s):

J. L. Demangeat ◽

P. Gries ◽

B. Poitevin

Keyword(s):

Aqueous Solutions ◽

Relaxation Times ◽

Water Proton ◽

Proton Relaxation ◽

Very High

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Zur Protonenrelaxation von Wasser an Silikagelen

Zeitschrift für Naturforschung A ◽

10.1515/zna-1967-1113 ◽

1967 ◽

Vol 22 (11) ◽

pp. 1751-1760 ◽

Cited By ~ 1

Author(s):

D. Michel

Keyword(s):

Water Clusters ◽

Relaxation Times ◽

Dipolar Interaction ◽

Relaxation Mechanism ◽

Silica Gels ◽

Proton Relaxation ◽

Relaxation Rates ◽

Proton Proton ◽

Adsorbed Molecules ◽

Paramagnetic Impurities

In most cases the proton relaxation of adsorbed liquids and gases is caused by the proton-proton dipolar interaction and the coupling between protons and paramagnetic impurities (e. g. Fe3+-ions) of the adsorbent. The latter relaxation mechanism, however, has been neglected up till now although in some commercial silica gels it’s contribution can be the most important one (see Section 2.2). Consequently, motional phenomena of adsorbed molecules can only be studied by NMR techniques if the relative largeness of these two relaxation rates has been estimated, as can be done by investigating the dependence of proton relaxation-times on the H/D-ratio. Relaxation-time measurements in the temperature range from —100° to +80°C indicate that proton transfers occur between surface hydroxils and adsorbed particles. In a sample of 3/4 statistical monolayer the presence of two different types of water, clusters containing 95% of the adsorbed molecules with correlation time τc2=2.7 · 10-10 s (0°C), and more individually adsorbed particles with τc1 ⪆ 2.3 ·10-8 (0°C), has been inferred (see Section 2.1).

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