Low-temperature properties of styrene–butadiene–styrene polymer modified bitumens

Low-temperature properties of the modified bitumens containing styrene–butadiene–styrene (SBS) polymers were investigated using conventional methods, dynamic mechanical analysis (DMA) and bending beam rheometer (BBR). Effects of the characteristics of base bitumens and polymers and the proportion of the components on these properties were studied. The results indicated that SBS polymers improved low-temperature properties of bitumens. The degree of improvement generally increased with SBS content and were influenced slightly by SBS structure. The study also showed a statistically linear relationships between different low-temperature parameters.     

Characterization of isotopic abundance measurements in high resolution FT-ICR and Orbitrap mass spectra for improved confidence of metabolite identification

Currently there is limited information available on the accuracy and precision of relative isotopic abundance (RIA) measurements using high-resolution direct-infusion mass spectrometry (HR DIMS), and it is unclear if this information can benefit automated peak annotation in metabolomics. Here we characterize the accuracy of RIA measurements on the Thermo LTQ FT Ultra (resolution of 100,000-750,000) and LTQ Orbitrap (R = 100,000) mass spectrometers. This first involved reoptimizing the SIM-stitching method (Southam, A. D. Anal. Chem. 2007, 79, 4595-4602) for the LTQ FT Ultra, which achieved a ca. 3-fold sensitivity increase compared to the original method while maintaining a root-mean-squared mass error of 0.16 ppm. Using this method, we show the quality of RIA measurements is highly dependent on signal-to-noise ratio (SNR), with RIA accuracy increasing with higher SNR. Furthermore, a negative offset between the theoretical and empirically calculated numbers of carbon atoms was observed for both mass spectrometers. Increasing the resolution of the LTQ FT Ultra lowered both the sensitivity and the quality of RIA measurements. Overall, although the errors in the empirically calculated number of carbons can be large (e.g., 10 carbons), we demonstrate that RIA measurements do improve automated peak annotation, increasing the number of single empirical formula assignments by >3-fold compared to using accurate mass alone.     

Relaxation versus cognitive therapies for dental fear--A psychophysiological approach.

By separating 127 adult dental-phobic patients according to fear etiology and psychophysiologic response style, the authors investigated the outcome of 2 dental fear treatments. Before and after either relaxation or cognitively oriented treatment, subjects were exposed to neutral and fear-relevant video sequences while the subjects' forehead muscle tension, heart rate, and skin conductance were recorded. Pre- to postintervention differences in self-reported dental fear, general fear, and trait anxiety were analyzed together with psychophysiological data. Both treatments resulted in a significant reduction of dental fear. Despite significant interaction effects of Treatment Modality × Psychophysiological Response Style, it could not be concluded that patients with different fear etiologies or response styles benefit differentially from the 2 treatments given. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nuclear microscopy in biomedical analysis with special emphasis on clinical metal biology

Nuclear microscopy based upon developments in high energy ion beam techniques is by now an accepted technique in many fields of research. The advancements into the biomedical field have, however, been slower than expected. A major factor explaining this tendency is the availability of nuclear microscopy. This paper reviews briefly the biomedical work using nuclear microscopy that has been carried out since the 4^th International Conference on Nuclear Microprobe Technology and Applications held in Shanghai. Nuclear microscopy of isolated individual blood cells from patients adversely affected by metal exposure from dental amalgam has been performed both before and after removal of the metallic fillings. The elemental profile of blood cells was more or less normalised after treatment. Some of these results will be presented to illustrate a medical application. Results from bulk analysis by ICP-MS of erythrocytes and plasma before and after treatment will also be presented to illustrate the difference in information content between these two approaches as well as the need for complementary information in solving biomedical problems. As part of a larger study of acute porphyria, nuclear microscopy of blood cells was included among the 78 laboratory tests. The approach in this study was unbiased in the sense that no hypothesis was formulated as to which laboratory parameters would be the most explanatory for health or disease. Multivariate discriminant analysis was applied to the large amounts of data acquired. This approach led to the hypothesis that oxidative stress increased the synthesis of manganese-dependent superoxide dismutase in the mitochondria of polymorphonuclear leukocytes, explaining the increase of manganese in these cells. Antioxidant therapy was therefore applied to a couple of patients with porphyria, however, without clinical success.     

Wärmetransformatoren für die Chemische Industrie aus der Sicht des Anwenders

Absorption heat transformers for the chemical industry as seen from a user's point of view. Absorption heat transformers can transfer waste heat, that could not hitherto be reused, to a higher temperature level. This is of special interest for the chemical industry, where there is both waste heat available at temperatures below 100°C and a demand for heat at 120 to 150°C. Though absorption heat transformers are able to recycle only a part of the total waste heat, they only need a negligible amount of additional, expensive exergy. The present status of development and advantages and disadvantages of the concept are discussed from a user's point of view. In view of the present low price of energy, special attention is given to economic considerations.