نتایج جستجو برای: styrene
تعداد نتایج: 6501 فیلتر نتایج به سال:
Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene (PS) bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as "purge and trap" and analysed by gas chromatograph-mass spectrometer (GC/MS). Eleven arom...
Two different mechanisms were responsible for the disappearance of styrene in enrichment cultures: (i) a mixed population of microorganisms, capable of utilizing styrene as a sole carbon source, oxidized this substrate to phenylethanol and phenylacetic acid; (ii) the culture also mediated polymerization of the monomer to low-molecular-weight styrene oligomers. This chemical reaction probably oc...
Styrene-specific N-7- and O6-guanine DNA adducts and N-terminal valine adducts were determined in mice tissues after the intraperitoneal administration of styrene. Blood, liver, lungs and spleen were collected 3 h after administration of various doses (from 0 to 4.35 mmol/kg b.w.) of styrene. DNA adducts were analysed by the modified 32P-postlabelling assay and N-terminal valine adducts were de...
Styrene is a commercially important chemical widely used in the manufacture of synthetic rubber, resins, polyesters and plastics. The highest levels of human exposure to styrene occur during the production of reinforced plastic products. The objective of this work was to evaluate both DNA and cytogenetic damage in styrene-exposed workers, analysing only non-smoker individuals. Environmental lev...
Styrene is discharged particulary from the factories of styrene resin and synthetic rubber, and it was listed as one of the offensive odor substances by the Offensive Odor Control Law in Japan at 1976. Styrene vapor has stimulating action on eye (STEWART et al. 1968) and membrana of nose and trachea (STEPHENSON & FOSDICK 1960). It has toxic effects on blood cells and liver (KATZ 1962), and nerv...
To elucidate the effect of maternal styrene exposure, which is due to various postnatal changes in the development and behavior of offspring, we investigated pregnancy-induced changes in the metabolism of styrene in rat liver in relation to the regulation of cytochrome P450 enzymes. We also examined age and sex-induced changes in the metabolism of styrene. Pregnancy appeared to exert a negative...
An effort was made to improve the separation issue of styrene-butadiene-styrene modifiers in styrene-butadiene-styrene-modified asphalt binders and further enhance their performance by adding nano-ZnO binder prepare compound modified binder. First, optimum dosage determined based on conventional tests, i.e., penetration, ring ball softening point, ductility at a fixed dosage; then, dynamic shea...
The styrene oxide isomerase (SOI) represents a membrane-bound enzyme of the microbial styrene degradation pathway and has been discussed as promising biocatalyst. It catalyzes the isomerization of styrene oxide to phenylacetaldehyde. In this study a styC gene, which encodes the SOI of Rhodococcus opacus 1CP, was optimized for optimal expression in Escherichia coli BL21(DE3) pLysS. The expressio...
The last few decades have seen a steady increase in the global production and utilisation of the alkenylbenzene, styrene. The compound is of major importance in the petrochemical and polymer-processing industries, which can contribute to the pollution of natural resources via the release of styrene-contaminated effluents and off-gases. This is a cause for some concern as human over-exposure to ...
To determine whether exposure to low levels of styrene (below 110 mg/m3) causes acute behavioural effects and symptoms that may be related to concentrations of styrene in air or urinary mandelic acid or both, 12 men occupationally exposed to styrene were studied and compared with a reference group of 10 unexposed men. Simple reaction time was measured before and after work and information about...
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