Field-dependent paramagnetic relaxation enhancement in solutions of Ni(II): What happens above the NMR proton frequency of 1 GHz?

An extended set of paramagnetic relaxation enhancement (PRE) data, up to the field of 32.9 Tesla, is reported for protons in an acidified aqueous solution of a Ni(II) salt in the presence and in the absence of added glycerol. For the 55% w/w glycerol sample, a distinct maximum in the PRE vs magnetic field curve is observed for the first time. The data are analysed using the Swedish slow-motion theory, including both the intramolecular (inner-sphere) and intermolecular (outer-sphere) contributions. The results indicate that estimating the outer-sphere part in the presence of the more efficient inner-sphere term is a difficult task.

NMR in pulsed high-field magnets and application to high-T(C) superconductors

This article deals with the implementation of Nuclear Magnetic Resonance (NMR) experiments in pulsed magnetic fields at the pulsed-field facility of the Laboratoire National des Champs Magnétiques Intenses and its application to the high-T(C) superconductor YBa2Cu3O6.51. The experimental setup is described in detail, including a low-temperature probe head adapted for pulsed fields. An entire paragraph is dedicated to the discussion of NMR in pulsed field and the introduction of an advanced deconvolution technique making use of the induction voltage in an additional pick-up coil. The (63)Cu/(65)Cu NMR experiments on an YBa2Cu3O6.51 single crystal were performed at 2.5K during a field pulse of 46.8-T-amplitude. In the recorded spectrum the (63)Cu center line and high-frequency satellites as well as the (65)Cu center line are identified and are compared with results in literature.

Combining one-dimensional stray-field micro-imaging with mechanical field-cycling NMR: a new spectrometer design

A new spectrometer design combining stray-field micro-imaging with mechanical field-cycling Nuclear Magnetic Resonance (FC-NMR), allowing for one dimensional spatial resolution in the order of 10 μm is described. The field-cycle is implemented by moving the probe in the stray-field of a superconducting gradient magnet. In this way a field range between 10 mT and 6.3 T is covered. The maximum transfer time is less than 5 s. Further, methods to correct for some of the imaging artefacts found in previous studies are implemented. The main objective of this design is a depth- and field-dependent investigation of the defect structure caused by heavy-ion irradiation of ionic crystals.

Spatially resolved nuclear spin relaxation, electron spin relaxation and light absorption in swift heavy ion irradiated LiF crystals

Spatially resolved (19)F and (7)Li spin-lattice relaxation rates are measured for LiF single crystals after irradiation with two kinds of swift heavy ions ((12)C of 133 MeV and (208)Pb of 1.78 GeV incident energy). Like in earlier studies on (130)Xe and (238)U irradiated LiF crystals, we found a strong enhancement of the nuclear spin-lattice relaxation rate within the ion penetration depth and a slight--but still significant--enhancement beyond. By evaluating the nuclear relaxation rate enhancement within the ion range after irradiation with different projectiles, a universal relationship between the spin-lattice relaxation rate and the dose is deduced. The results of accompanying X-band electron paramagnetic resonance relaxation measurements and optical absorption spectroscopy are included in a physical interpretation of this relationship. Also the reason for the enhanced relaxation rate beyond the ion range is further discussed.

Flat RF coils in static field gradient nuclear magnetic resonance

The use of flat RF coils allows considerable gains in the sensitivity of static field gradient (SFG) nuclear magnetic resonance (NMR) experiments. In this article, this effect is studied theoretically as well as experimentally. Additionally, the flat coil geometry has been studied theoretically depending on magnetic field gradient, pulse sequence and amplifier power. Moreover, detecting the signal directly from the free induction decay (FID) turned out to be quite attractive for STRAFI-like microimaging experiments, especially when using flat coils. In addition to wound rectangular flat coils also spiral flat coils have been developed which can be manufactured by photolithography from printed circuit boards.

Spatially resolved characterization of Xe ion irradiated LiF crystals using static field gradient NMR

Spatially resolved (19)F and (7)Li nuclear magnetic resonance (NMR) spin-lattice relaxation rates have been measured in LiF crystals irradiated with 1.44 GeV Xe ions at fluences from 10(10) to 10(12) ions cm(-2). In addition, the F-centre concentration has been measured by optical absorption spectroscopy and the concentration of paramagnetic centres by electron paramagnetic resonance (EPR). Within the ion range, the relaxation rate turns out to increase linearly with the concentration of paramagnetic centres but super-linearly with the F-centre concentration. Beyond the ion range, the relaxation rate is still significantly enhanced compared to non-irradiated LiF.

Spatially resolved characterization of heavy ion irradiated crystals using static field gradient nuclear magnetic resonance

Static magnetic field gradient NMR has been used for one-dimensional spatial (19)F spin-lattice relaxation profile studies (resolution of the order of 10 µm) in a LiF crystal irradiated with U ions. Technical aspects of the use of large static magnetic field gradients are discussed as well as a special data acquisition mode allowing for effectively measuring spatially resolved spin-lattice relaxation rates as low as 10(-3) s(-1). In addition to the expected enhanced spin-lattice relaxation rate within the ion range, also an enhanced rate beyond the ion range has been found.

High temperature mechanical field-cycling setup

A new design of a mechanical field-cycling setup, operating in the wide temperature range up to 1200 K has been implemented. The sample is moved by a stepping motor in the stray field of a superconducting magnet inside a furnace of homogeneous temperature profile. For a field range from 0.75 to 7 T (transfer length 24 cm), the transfer time is less than 100 ms. The temperature profile is homogenized to better than 1% of the absolute set temperature. The main objective of this design is to extend the T1 relaxation dispersion range covered by electronic field-cycling to higher frequencies.

Single-sided and semisingle-sided NMR sensors for highly diffusive samples: application to bottled beverages

Single-sided NMR sensors such as the NMR-MOUSE have been very successfully implemented for quality control applications in the rubber and polymer industries. More recently, single-sided NMR was also applied in characterization of the fat components in foods. Both industrial polymers and the fat components in food exhibit relatively low self-diffusion coefficients on the order of 5x10(-11) m2/s or lower. The application of conventional single-sided NMR to highly mobile, watery phases in foods and beverages is hampered by the strong magnetic field gradient present in standard single-sided NMR devices. In this contribution, we present both a single-sided NMR sensor with a reduced magnetic field gradient and another ("semisingle-sided") sensor design with an open sample bay using a single-sided RF coil. The latter design allows much better sensitivity without sacrificing the necessary open access needed for measurements on entire food packages such as bottles. As a first application, the sensors were used for determining the oxygen content in bottles with superoxygenated table water.

[The Mannheim Cohort Project--prevalence of psychogenic diseases in cities]

For the purpose of our research project the term 'psychogenetic disorders' covers psychoneuroses , character neuroses in a broader sense, and functional-vegetative as well as psychosomatic affections. So far information concerning basic descriptive-epidemiological data, especially the frequency of occurrence and the dependence upon demographic variables of the above mentioned disorders, is insufficient and controversial. Even less satisfactory is our information on the progress of these disorders. The specific difficulty with the diagnostic apperception of these disorders in particular requires field research within the entire population. Only by means of such a very expensive procedure can valid information on the true prevalence or incidence of the above mentioned disorders be obtained. Moreover, for a follow-up design each test subject must be examined several times by highly qualified experts, each examination requiring his personal presence. The "Mannheimer Kohortenprojekt" involves six hundred test subjects, two hundred each born in 1935, 1945, and 1955, selected at random from the 'normal' general population. They were examined with the aid of a structured interview schedule oriented on psychoanalytic principles and with other instruments (lists of complaints, inventories of life events, FPI-tests, etc.). Results from the first three-year investigation period include: Out of the total of six hundred test subjects twenty-five per cent are "cases". Women are significantly in the majority. Apparent is an obvious connection between different types of complaints and the social class of the test subject. Identified disorders show correlations with life events on the one hand and with early childhood disturbances on the other.

[Bilrubinemia after administration of nicotinic acid (author's transl)]

Nicotinic acid concentrations in the serum over 80 mug/100 ml induce at the start of high dosage nicotinic acid therapy an acute rise in bilirubin to 1-3mg/100 ml serum. Even after postprandial administration there are clearly raised bilirubin concentrations in the serum. After treatment for 1 week with 0.5 g nicotinic acid daily by mouth the bilirubin increase is no longer detectable. The increased bilirubin concentrations in the serum are apparently the result of a transient inhibition of glucuronyl-transferase and is not a symptom of an acute liver disorder. When starting high dosage nicotinic acid therapy, therefore, disorders of the bilirubin metabolism and liver function must be excluded by differential diagnosis in doubtful cases. Further investigations are necessary to see whether the high concentrations of nicotinic acid in the serum cause competition with other drugs for the bilirubin-specific glucuronyl-transferase.