Implications of psychological research on stress and technological accidents.

Psychological research on stress, disasters, and human-made technological accidents have important implications for policy, planning, and legal resolution of situations caused by environmental hazards. The incidence of technological accidents and catastrophes seems to have increased, and the biobehavioral sequelae of such accidents among victims have implications for mental and physical health as well as for intervention and prevention. In this article, research on the long-term effects of human-made disasters is discussed in the context of contributions that psychological research and theory can make in decisions regarding where potential hazards are located, how they are managed, and how accidents are handled. Unique psychophysiological processes associated with toxic accidents make these stressors more potent and likely to cause long-term uncertainty and chronic stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Limited value of fluorine-18-fluorodeoxyglucose PET for the differential diagnosis of focal liver lesions in patients with chronic hepatitis C virus infection

AIM: The differentiation of HCC from liver metastasis or benign disorders by imaging studies based upon morphological aspects may be difficult. METHOD: In order to evaluate the role of tumour metabolism, we performed FDG-PET (whole-body PET and transmission-corrected regional scans of the liver as well as the SUV determined 60 min after injection of FDG) in ten consecutive patients with HCV-associated focal liver lesions. Definite diagnosis was established after ultrasound-guided liver biopsy followed by histopathological examination. These results were compared with ultrasound, computed tomography, serum anti-p53, and p53 protein expression. RESULTS: The histologic examination revealed a HCC in five patients, regenerative nodules in three patients, and liver metastasis (primary malignancy: one adenocarcinoma and one neuroendocrine tumour) in the remaining two patients. Three of ten lesions were detectable by FDG-PET: two HCCs and one metastatic adenocarcinoma. Seven lesions were not distinguishable by FDG-PET (three HCCs, three regeneration nodules and one metastatic neuroendocrine tumour). In each patient hepatic lesions were visible either by ultrasound or CT. Both tumours (metastatic adenocarcinoma, moderately well-differentiated HCC) with the strongest expression of p53 also presented with highly increased FDG uptake. CONCLUSIONS: FDG-PET is not superior to ultrasound or CT and therefore does not allow the non-invasive differentiation of HCV-associated focal liver lesions. Tissue-diagnosis by means of liver-biopsy followed by histopathological examination remains the gold-standard for the differentiation of HCV-related liver lesions. The finding of the relationship of p53 protein overexpression with the SUV needs further confirmation.     

A sequential procedure for multihypothesis testing

The sequential testing of more than two hypotheses has important applications in direct-sequence spread spectrum signal acquisition, multiple-resolution-element radar, and other areas. A useful sequential test which we term the MSPRT is studied in this paper. The test is shown to be a generalization of the sequential probability ratio test. Under Bayesian assumptions, it is argued that the MSPRT approximates the much more complicated optimal test when error probabilities are small and expected stopping times are large. Bounds on error probabilities are derived, and asymptotic expressions for the stopping time and error probabilities are given. A design procedure is presented for determining the parameters of the MSPRT. Two examples involving Gaussian densities are included, and comparisons are made between simulation results and asymptotic expressions. Comparisons with Bayesian fixed sample size tests are also made, and it is found that the MSPRT requires two to three times fewer samples on average     

Sex differences in sensitivity of the hypothalamic-pituitary-adrenal axis.

Two studies examined sex differences in responsiveness of the hypothalamic-pituitary-adrenal cortical axis, a major component of the stress response. The first measured pituitary-adrenal responses to ovine corticotropin-releasing hormone (oCRH) in 24 healthy men and 19 healthy women. Plasma adrenocorticotropin hormone responses to oCRH were significantly greater among women than among men. In contrast, cortisol concentrations were similar in both groups, though elevations were more prolonged in women. Differences in corticotropin-releasing activity between men and women may help account for these findings; such differences in central components of the stress response might play a role in the known epidemiological differences in diseases of stress system dysregulation between men and women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Untersuchungen vollsynthetischer Kohlenwasserstoff-Wachse

Investigation of Fully Synthetic Hydrocarbon Waxes Methods for the structural investigation of synthetic hydrocarbon waxes of a new series of Ruhrwaxes are reported. Besides the molecular weight distribution, which is determined by fractional extraction of the hydrocarbon waxes with an organic solvent and characterization of the fractions by means of molecular weights, solidification points and refractive indices, properties like ability to form adducts with urea, dilatometric and calorimetric measurements as well as assay of IR spectra serve for elucidating the structure and composition.     

Scattering and absorption property database for nonspherical ice particles in the near- through far-infrared spectral region

The single-scattering properties of ice particles in the near- through far-infrared spectral region are computed from a composite method that is based on a combination of the finite-difference time-domain technique, the T-matrix method, an improved geometrical-optics method, and Lorenz-Mie theory. Seven nonspherical ice crystal habits (aggregates, hexagonal solid and hollow columns, hexagonal plates, bullet rosettes, spheroids, and droxtals) are considered. A database of the single-scattering properties for each of these ice particles has been developed at 49 wavelengths between 3 and 100 microm and for particle sizes ranging from 2 to 10,000 microm specified in terms of the particle maximum dimension. The spectral variations of the single-scattering properties are discussed, as well as their dependence on the particle maximum dimension and effective particle size. The comparisons show that the assumption of spherical ice particles in the near-IR through far-IR region is generally not optimal for radiative transfer computation. Furthermore, a parameterization of the bulk optical properties is developed for mid-latitude cirrus clouds based on a set of 21 particle size distributions obtained from various field campaigns.     

RNA helicases: versatile ATP-driven nanomotors

RNA helicases are a large family of molecular motors that utilize nucleoside triphosphates to unwind RNA duplexes and to remodel RNA protein complexes. In this review, we discuss the structure and function of RNA helicases with an emphasis on the potential application of these enzymes to control conformational changes in nanoassemblies that contain RNA.     

Aktuelle Probleme bei der Ultraschallprüfung von Freiformschmiedestücken

Die routinemäßige Ultraschallprüfung von Schmiedestücken und ihre Grenzen. Festlegungen in Regelwerken, Forderungen hinsichtlich Registrier- und Zulässigkeitsgrenzen. Prüfung austenitischer Bauteile, Einsatz spezieller Prüfköpfe und Geräte. Möglichkeiten der Automatisierung, Ausblick auf zukünftige Entwicklungen.