The method of headspace solid phase microextraction (HS/SPME) was successfully used in a simultaneous multicomponent analysis of hexachlorobenzene (HCB), tefluthrin, heptachlor, aldrin, chlorpyrifos, fenthion and bifenthrin in aqueous medium. Measurements were performed using a nonpolar polydimethyl siloxane (PDMS) fiber. Detection and quantification were done by gas chromatography/mass spectro...

The effects of varying temperatures from 25 degrees to 37 degrees C on calcium binding characteristics of sarcoplasmic reticulum from malignant hyperthermia-susceptible (MHS) and control pig muscle were examined. Two groups of MHS pigs were included: those with high susceptibility to malignant hyperthermia (MHS group) and a cross-bred, less susceptible group (MHX). At 25 degrees C, calcium bind...

The present study aims to provide data about the time required for Cynopoecilus melanotaenia kept at different temperatures to complete embryonic development. This information can be valuable for optimizing laboratory culture and facilitating future use of this species as a test organism in toxicity tests. Temperature effects on hatching rate are presented as well as information related to embr...

Three side-chain analogues of cholecalciferol (vitamin D3) modified at C-25, namely 25-fluorocholecalciferol, 24-dehydrocholecalciferol and 25-dehydrocholecalciferol, conceived as potential inhibitors of the cholecalciferol 25-hydroxylase have been prepared and tested in the rat. These compounds markedly diminish conversion in vivo of cholecalciferol into 25-hydroxycholecalciferol, but are not ...

In view of the world-wide efforts to optimize and standardize the determinations of enzyme activities in clinical chemistry, the agreement upon a uniform reaction temperature is of essential importance. Both on the basis of practical technical considerations and for physical chemical reasons, 25°C is the best temperature for standard measurements. The following considerations make the lowest po...

In Clark and Shelby soybean (Glycine max [L.] Merr.) seedlings, hypocotyl elongation was inhibited and hypocotyl swelling and root dry weight were increased by a temperature of 25 C. At 20 and 30 C, development was normal, as was development of Hawkeye and Mandarin soybean seedlings at all three temperatures. Dry matter distribution at 9 days indicates that inhibition of hypocotyl elongation is...

The respiratory rates of mycelia of the mesophilic fungus, Aspergillus niger, and the thermophilic fungus, Thermomyces lanuginosus, were comparable at their respective temperature optima for growth. The respiratory rate of A. niger was independent of changes in temperature between 15 and 40 C. The respiratory rate of T. lanuginosus increased with increase in temperature between 25 and 55 C.

The success of a biological invasion relies on the environment and is closely linked to factors such as water and temperature. Invasive plant species display different seed characteristics, including shape. Field sandbur (Cenchrus pauciflorus) is a globally widespread invasive species capable of adapting to broad environmental conditions. However, its germination response to water and temperatu...

Temperature is expected to modify the effects of ultraviolet radiation (UVR) on photosynthesis by affecting the rate of repair. We studied the effect of short-term (1 h) and long-term (days) acclimation to temperature on UVR photoinhibition in the diatom Thalassiosira pseudonana Hasle et Heimdal. Photosynthesis was measured during 1 h exposures to varying irradiances of PAR and UVR + PAR at 15,...