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The debate about the digitalization has gained momentum in recent years. While digitalization technologies are globally hailed as drivers of increased productivity, they are not yet used on a grand...

Background Environmental factors are likely to be involved in the pathogenesis of inflammatory bowel disease (IBD), as the incidence of both Crohn's disease (CD) and ulcerative colitis (UC) increased with improved living standards in Europe after World War II. On the basis of earlier reports suggesting that hygienic standards may also play a role in the pathogenesis of IBD, we investigated the influence of hepatitis A seroprevalence as an indicator for poorer hygienic conditions and worm infestations in IBD. Methods Hepatitis A seroprevalence was examined in patients with UC and CD. Patients with minor endocrinological disorders served as controls. All patients were questioned about immunizations, parasitic infections (worms), contact with animals, living on a farm, and ever traveling abroad. Patients were excluded for active hepatitis A immunization or recent passive immunization. Results are presented as Mantel-Haenszel odds ratios with 95% confidence interval, adjusted for age group. Results The sample included 307 patients (73 CD, 48 UC, and 186 controls). Hepatitis A seroprevalence was strongly associated with age older than 50 years. Age adjusted Mantel-Haenszel odds ratios were 0.25 (0.09-0.71) for UC and 0.75 (0.38-1.46) for CD versus controls. For parasitic infections, the odds ratios were 1.15 (0.52-2.53) for UC and 0.34 (0.13-0.89) for CD. Conclusion We were able to demonstrate a negative association of hepatitis A infection with UC only. In contrast, a novel finding was a strong protective effect of worm infestations for the occurrence of CD, but not UC.

The resonance frequency of the 205T1 nucleus in molten solutions of the thallous halides with the corresponding alkali metal halides varies linearly with the mole fraction of the added alkali halide. The direction of the chemical shift depends upon the radius of the alkali cation, being upfield for lithium and sodium halides and downfield for the halides of potassium, rubidium, and cesium relative to the pure thallous halide. For a given mole fraction of alkali halide, δT1 is a linear function of the alkali cation radius. The results provide information on the nature of the interactions between cations and anions in molten salts. The covalent interaction between T1+ and halide ions is decreased by alkali metal ions of small radius and increased by those of large radius.

The apparent "two-line" hyperfine spectrum of Fe57 in some orthopyroxene minerals from metamorphic rocks has been analyzed by the Mossbauer technique. The spectrum consists predominantly of two overlapping two-line patterns. The patterns have been assigned to the two non-equivalent Fe2+ sites, M1 and M2, of the crystal structure. The approximated intrinsic values of the electric quadrupole interaction \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage{wasysym} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document}$$\frac{1}{2} |e^{2}qQ| (1 + [\eta^{2}/3])^{1/2}$$\end{document} and isomer shifts at M1 and M2 are: The Fe2+ site occupancies have been approximately determined. The high degree of Mg-Fe ordering in an orthopyroxene (Fe/[Mg + Fe] = 0.535) found previously by X-ray diffraction has b...

The nuclear quadrupole coupling constants and isomer shifts of 57Fe in the spinels ZnFe2O4 and CdFe2O4 were measured using the Mossbauer effect. The signs of the quadrupole coupling constants were determined from spectra which were taken in an applied magnetic field. The sign is negative in both spinels. The isomer shifts and Fe–O distances indicate that Fe3+ in ZnFe2O4 is somewhat more covalently bonded than in CdFe2O4. The external field gradients at the Fe3+ positions can be interpreted in terms of the ionic point‐multipole model modified by some charge transfer between oxygen and the cations. The point charge contribution to the field gradient is positive in case of ZnFe2O4 and nearly zero in case of CdFe2O4; the predominant contribution is due to the electric dipole moments of the oxygen ions and is negative. The dipole polarizability of the oxygen ion which gave the best fit is αD = 0.8 A3. The effect of charge transfer on the ionic field gradient is small.

The original samples of the magnetite series Fe3O4–γFe2O3 of G.Hägg have been investigated with x-ray diffraction and Mössbauer spectroscopy. X-ray diffraction studies showed that the intensities of the superstructure lines increase with increasing deviation from the stoichiometric ratio. The patterns of all samples exhibited a cubic-primitive lattice. Tetragonal symmetry was not observed. Mössbauer absorption spectra gave evidence for vacancy distributions over tetrahedral as well as octahedral iron sites of magnetite. Broadening of the octahedral iron lines indicated that the relaxation times of the hopping electrons at constant temperature increases as the deviation from the stoichiometric ratio increases.

At constant magnetic field the resonance frequencies of nuclei in ionic salts increase linearly with temperature in both the crystalline and molten states. The linear temperature-dependence of the chemical shift is ascribed to the excitation of higher paramagnetic electronic states which accompanies the increasing overlap of cation and anion wave functions; both are proportional to the linear increase in the mean squared vibrational amplitude of ions with temperature. The magnitude of the break in the chemical shift at the melting point, coupled with a knowledge of the change in the coordination number and the variation in the wave function overlap with internuclear separation leads to an estimate of the distance of closest approach of neighboring ions in the molten state. For an assumed value of F=0.9, where F= (ZL/Zs)/(ΔEʟ/ΔES), the distance of closest cation-anion approach decreases by 0.18 Å as crystalline TlCl melts to form the liquid salt. The overlap of Tl+ and Cl- ions in crystalline TlCl at room temperature is 0.012 on the basis of the NMR frequency of 205Τl+ and is estimated to be 0.017 from machine calculations based on analytic wave functions for the ground states of the ions.

The nuclear quadrupole coupling tensors of 27Al at the two crystallographically nonequivalent Al3+ sites in andalusite, Al2SiO5, have been determined from nuclear magnetic resonance measurements. For this, the Hamiltonian matrix for the mixed magnetic and electrostatic interaction was diagonalized and a minimization technique based on the least‐squares principle was used. The quadrupole coupling constants and asymmetry parameters are: Site Al1 eQVzz = 15.6 MHz, η = 0.08 (octahedral); Site Al2 eQVzz = 5.9 MHz, η = 0.70 (5‐coordinated). The site assignment which cannot be made from NMR data alone is based on point charge calculations (point multipole model). Previous assignments concluded from EPR data of Fe3+ and Cr3+ impurities at the Al3+ sites are confirmed. The principal axes of the magnetic Fe3+ and Cr3+ tensors deviate from the 27Al tensor axes by 1°–10°.

Relatively large chemical shifts in the resonance frequency of the thallium nucleus are observed in both the crystalline and molten states of different thallium salts. Relative to TlNO3, which appears to be the most ionic of all thallium salts studied, the 205Tl resonance frequency at fixed field increases in the order: NO3—

Two designs are described for single coil NMR probes and furnaces with the Varian wide line spectrometer (V‐4210) to temperatures up to 1000°C. Their application to molten salt systems is outlined.