Search results for "Cold Temperature"
showing 10 items of 166 documents
Effect of cold drawing on mechanical properties of biodegradable fibers.
2016
Purpose Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be…
Fragmenting gadolinium: Mononuclear polyoxometalate-based magnetic coolers for ultra-low temperatures
2012
The polyoxometalate clusters with formula [Gd(W 5O 18) 2] 9- and [Gd(P 5W 30O 110)] 12- each carry a single magnetic ion of gadolinium, which is the most widespread element among magnetic refrigerant materials. In an adiabatic demagnetization, the lowest attainable temperature is limited by the presence of magnetic interactions that bring about magnetic order below a critical temperature. We demonstrate that this limitation can be overcome by chemically engineering the molecules in such a way to effectively screen all magnetic interactions, suggesting their use as ultra-low-temperature coolers. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Two Rare Northern Entoloma Species Observed in Sicily under Exceptionally Cold Weather Conditions
2011
The biology and ecology of manyEntolomaspecies is still poorly known as well as their geographical distribution. In Italy, there are no studies on the influence of weather on fungal abundance and richness and our knowledge on the ecology and distribution ofEntolomaspecies needs to be improved. The discovery of twoEntolomaspecies in Sicily (southern Italy), reported in the literature as belonging to the habitat of north European countries, was the basis leading to the assumption that anomalous climatic conditions could stimulate the growth of northern entolomas in the southernmost Mediterranean regions. The results of this study show that the presence of northernEntolomaspecies in Sicily is …
Unsaturated fatty acids from food and in the growth medium improve growth of Bacillus cereus under cold and anaerobic conditions.
2013
International audience; In a chemically defined medium and in Luria broth, cold strongly reduced maximal population density of Bacillus cereus ATCC 14579 in anaerobiosis and caused formation of filaments. In cooked spinach, maximal population density of B. cereus in anaerobiosis was the same at cold and optimal temperatures, with normal cell divisions. The lipid containing fraction of spinach, but not the hydrophilic fraction, restored growth of B. cereus under cold and anaerobiosis when added to the chemically defined medium. This fraction was rich in unsaturated, low melting point fatty acids. Addition of phosphatidylcholine containing unsaturated, low melting point, fatty acids similarly…
Pathophysiological approaches to identifying tumor hypoxia in patients
1991
The present report summarizes observations of the authors on tumor oxygenation and on techniques for characterizing tumor hypoxia in patients. Cryospectrophotometric measurements of HbO2 saturations in tumor microvessels allow for estimates of the proportion of well oxygenated tissue regions. Labeling of tissue areas at oxygen (O2) tensions (pO2) less than 10 mm Hg with misonidazole may be used for a general characterization of the oxygenation status in patient tumors rather than for the determination of the radiobiologically hypoxic cell fraction. Quantitative bioluminescence and single photon imaging make it possible to determine ATP concentrations in absolute terms with a spatial resolut…
The cold shock response of the psychrotrophic bacterium Pseudomonas fragi involves four low-molecular-mass nucleic acid-binding proteins
1997
The psychrotrophic bacterium Pseudomonas fragi was subjected to cold shocks from 30 or 20 to 5 degrees C. The downshifts were followed by a lag phase before growth resumed at a characteristic 5 degrees C growth rate. The analysis of protein patterns by two-dimentional gel electrophoresis revealed overexpression of 25 or 17 proteins and underexpression of 12 proteins following the 30- or 20-to-5 degrees C shift, respectively. The two downshifts shared similar variations of synthesis of 20 proteins. The kinetic analysis distinguished the induced proteins into cold shock proteins (Csps), which were rapidly but transiently overexpressed, and cold acclimation proteins (Caps), which were more or …
Global, regional, and national burden of mortality associated with non-optimal ambient temperatures from 2000 to 2019: a three-stage modelling study
2021
Background: Exposure to cold or hot temperatures is associated with premature deaths. We aimed to evaluate the global, regional, and national mortality burden associated with non-optimal ambient temperatures. Methods: In this modelling study, we collected time-series data on mortality and ambient temperatures from 750 locations in 43 countries and five meta-predictors at a grid size of 0·5° × 0·5° across the globe. A three-stage analysis strategy was used. First, the temperature–mortality association was fitted for each location by use of a time-series regression. Second, a multivariate meta-regression model was built between location-specific estimates and meta-predictors. Finally, the gri…
Carotenoid Profile Modification during Refrigerated Storage in Untreated and Pasteurized Orange Juice and Orange Juice Treated with High-Intensity Pu…
2006
A comparative study was made of the evolution and modification of various carotenoids and vitamin A in untreated orange juice, pasteurized orange juice (90 degrees C, 20 s), and orange juice processed with high-intensity pulsed electric fields (HIPEF) (30 kV/cm, 100 micros), during 7 weeks of storage at 2 and 10 degrees C. The concentration of total carotenoids in the untreated juice decreased by 12.6% when the juice was pasteurized, whereas the decrease was only 6.7% when the juice was treated with HIPEF. Vitamin A was greatest in the untreated orange juice, followed by orange juice treated with HIPEF (decrease of 7.52%) and, last, pasteurized orange juice (decrease of 15.62%). The decreas…
Regional cerebral blood flow and regional metabolism in cold induced oedema.
1973
24 hours following a cold induced oedema in cats rCBF was measured in the lesion area, the bluish stained cortex immediately adjacent to the lesion, a cortical area remote from the lesion, and in the contralateral uninjured hemisphere. Thereafter the brain was frozen and the respective tissue areas were removed and analyzed for water and electrolyte content as well as metabolite concentrations. It seems, that in the neighbourhood of a local lesion at least 3 different brain regions can be differentiated with regard to their characteristic pattern of data. In non-oedematous regions either hyperaemia or hypoaemia could be observed. In areas with local brain oedema rCBF was reduced inversely p…
Extracellular space and electrolyte distribution in cortex and white matter of dog brain in cold induced oedema
1973
24 hours after a circumscribed cold injury of the cortex dog brains were perfused from the lateral ventricle and the frontal subarachnoidal space to the cisterna magna with an artificial CSF containing trace amounts of35S-labelled thiosulphate. Simultaneously the extracellular tracer was administered intravenously. Extracellular fluid volume was estimated and found to be increased from 10 to 15% in the oedematous cortex and from 10 to 27% in the oedematous white matter. The actual size of ECS in oedematous white matter, however, must be larger as indicated by the relative alterations of thiosulphate distribution, tissue water, sodium and chloride. Apparently a small part of the fluid accumu…