Phosphorescence and fluorescence of poly(vinyl alcohol) films

Luminescence properties of poly(vinyl alcohol) (PVA) films were investigated at room and low (103 K) temperatures. It was estimated that the PVA films can be regarded as luminescentless matrices when excited by radiation of wavelengths greater than 420 nm (λ_exc ≥ 420 nm).     

The magnetic compass mechanisms of birds and rodents are based on different physical principles.

Recently, oscillating magnetic fields in the MHz-range were introduced as a useful diagnostic tool to identify the mechanism underlying magnetoreception. The effect of very weak high-frequency fields on the orientation of migratory birds indicates that the avian magnetic compass is based on a radical pair mechanism. To analyse the nature of the magnetic compass of mammals, we tested rodents, Ansell's mole-rats, using their tendency to build their nests in the southern part of the arena as a criterion whether or not they could orient. In contrast to birds, their orientation was not disrupted when a broad-band field of 0.1-10MHz of 85nT or a 1.315MHz field of 480nT was added to the static geomagnetic field of 46000nT. Even increasing the intensity of the 1.315MHz field (Zeeman frequency in the local geomagnetic field) to 4800nT, more than a tenth of the static field, the mole-rats remained unaffected and continued to build their nests in the south. These results indicate that in contrast to that of birds, their magnetic compass does not involve radical pair processes; it seems to be based on a fundamentally different principle, which probably involves magnetite.     

Expression of alpha-D-mannosidase in man-hamster somatic cell hybrids

Two types of alpha-D-mannosidase isozymes are present in human white blood cells, human diploid fibroblasts, and HeLa cells. One of these (the S isozyme) constitutes the major alpha-D-mannosidase of the human cells, has a pH optimum of 4.4, and is associated with lysosomes. The other (the F isozyme) is most active at pH 6, is acid labile, and is located in the soluble portion of the cytoplasm. The expression of human lysosomal alpha-D-mannosidase was examined in man-hamster hybrid clones, and was found to be concordant with that of phosphohexose isomerase in 54 of 55 primary clones. A locus specifying human lysosomal alpha-D-mannosidase has therfore been assigned to chromosome 19.     

Effects of induced mood on self-reported life events and perceived and received social support.

Tested the relation between mood (depressed [D], elated [E], or neutral [N]), induced by the Velten (1968) procedure, and college students' responses on a subjectively scored life events questionnaire and measures of perceived and received social support. A manipulation check showed that the mood manipulation was successful. There was a significant mood effect on the number of self-reported negative life events, with E Ss reporting the fewest. However, mood had no significant effect on the number of self-reported positive life events or the rated intensity of negative and positive events. Mood had a significant effect on perceived social support, with D Ss scoring the lowest. Self-report of received social support, however, was not affected by the mood manipulation. The findings challenge the widespread use of life event and perceived social support questionnaires whose independence from a mood-related response bias has not been adequately demonstrated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Smoke from thermal insulation materials

The smoke-producing characteristics of various materials are discussed with particular attention to thermal insulation. The different methods of measuring smoke density are described, and selected data are presented. Product Safety Corporation     

Chemoprotective action of l-(+)-selenomethionine on the modulation of genes involved in oxidative stress and in the UPR pathway

The installation of oxidative process arises from an imbalance between oxidants and antioxidants compounds, in favor of excessive generation of free radicals. This process can affect cellular components, like endoplasmic reticulum (ER). The ER is extremely sensitive to changes in homeostasis, where, on different stimuli, may result in adaptation to survival or induction of apoptosis (unfolded protein response, “UPR” pathway). The oxidative damage caused by endogenous or exogenous agents or a dysregulation of the UPR pathway can lead to adverse conditions, whose chronicity has important implications for the etiology of chronic diseases, including cancer. Therefore, it becomes important to search for chemoprotective agents aiming their role in preventive medicine. Between these substances, selenium’s antioxidant activity seems to be effective in treating diseases which have the oxidative stress as its development. We evaluated the modulating action of l-(+)-selenomethionine (SeMet) in HepG2 cells against cellular stress induced by H₂O₂ through MTT assay, comet assay, and gene expression by qRT-PCR of genes related to oxidative stress, UPR pathway, and apoptosis. In MTT assay, the lower concentrations of SeMet showed a cytoprotective action against the damage caused by H₂O₂. Likewise, it was verified in the comet assay that the concentration of 50 ng/mL reduced the genotoxic damage caused by H₂O₂. SeMet at 50 ng/mL regulated the genes tested in the qRT-PCR, showing an antiapoptotic and antioxidant effect. These results suggest that SeMet positively modulates the genes of oxidative stress and ER, leading to a chemoprotective and antioxidant effect, becoming an alternative in preventive medicine.     

Rheological Properties of Frozen Concentrated Orange Juice (FCOJ) as a Function of Concentration and Subzero Temperatures

Data on flow properties of Frozen Concentrated Orange Juice (FCOJ) produced from oranges cv. Pera-Rio (65.04 °Brix, 8.8% w/w pulp content, 2.5% w/w pectin, 3.84% citric acid, 1.293 g cm^?3) from ?18 to 0°C were fitted with appropriate predictive models. The power law model was found to be the most appropriate to fit the flow curves obtained for FCOJ between 46.56 and 65.04 °Brix. In higher concentrations, thixotropy was observed and showed more temperature dependence. A single equation combining Arrhenius and exponential relationships was applied to describe the temperature effect and shear rate on the quantity of breakdown of FCOJ.