A simple sequential injection (SI) method is reported for the determination of the non-ionic surfactant polyoxyethylene sorbitan monoleate (Tween-80). The proposed method is based on a fluorescence enhancement of the probe 4',5'-dibromo-2',7'-dinitro fluorescein, disodium salt (Eosin B) in the presence of a surfactant. The procedure is optimized using the univariate method of optimization. The ...

One of the phenoxy herbicides, 2-methyl-4-chlorophenoxyacetic acid (MCPA) was soaked with pellet dissolved by corn oil and given to ICR male mice for 18 months at levels of 40, 200, 1,000 and 5,000 ppm (about 3.9, 19.0, 95.6 and 566.4 mg/kg/day, respectively). The animals were then placed on a control diet for 12 months. Treatment with 5,000 ppm of MCPA resulted in a significantly decreased sur...

The methanol and ethyl acetate (EA) extracts of four species of sea lily (Himerometra magnipinna, Comaster multifidus, Comanthina sp., and Comatella maculata) were evaluated for their insecticidal activity against Yellow-fever mosquito larvae (Aedes aegypti) and their repellency against adult Asian Tiger mosquitoes (Aedes albopictus). The 24-hr minimum inhibition concentration (MIC) data reveal...

Exposure to chlorine gas (Cl2) causes occupational asthma that we hypothesized occurs through the induction of airway inflammation and airway hyperresponsiveness by oxidative damage. Respiratory mechanics and airway responsiveness to methacholine were assessed in A/J mice 24 hours after a 5-minute exposure to 100, 200, 400, or 800 ppm Cl2 and 2 and 7 days after inhalation of 400 ppm Cl2. Airway...

The adult rat brain develops through an interplay of neuronal proliferation and programmed cell death. Steroid hormones and growth factors may alter the balance between these competing processes. "Endocrine disrupters" (EDs) may also alter brain development, by mimicry or modulation of endogenous hormone systems. Under control conditions, the sexually dimorphic nucleus (SDN) of the medial preop...

this study was conducted in order to evaluate the effect of thyme (thymus vulgaris l.) and oregano (oreganum vulgare l.) essential oils on performance, carcass characteristics, antioxidant status and blood biochemical parameters in broiler chickens. a total of 216 as-hatched broilers (ross-308) were divided into 6 treatments with 3 replications of 12 birds per each. experimental treatments were...

The effects on Simulium adersi and S. hargreavesi larvae of 2 Bacillus thuringiensis var. israelensis products, the liquid formulation "Teknar" (Sandoz) and a powder formulation produced by the Ben Gurion University, Israel, were compared in the laboratory and in the Pienaars River. This river was heavily polluted with effluent from a nearby sewage works and contained 77 mg/l chloride. In the l...

Olive mill wastewater was treated by an aerobic bio-process at different values of pH (with or without addition of lime), for 45 days on a laboratory scale, to evaluate the reduction of the organic load. The lipid content showed an appreciable change in relation to the applied treatment both for total lipids and for the different fractions (neutral lipids, monoglycerides and phospholipids). 13C...

Several explanations for the 200 to 280 ppm glacial/interglacial change in atmospheric CO 2 concentrations deal with variations in southern ocean phytoplankton productivity and the related use or nonuse of major plant nutrients. An hypothesis is presented herein in which arguments are made that new productivity in today's southern ocean (7.4 X 1013 g yr -1) is limited by iron deficiency, and he...

Different molecular weight (MW) chitosans (5.5!10 to 15.5!10 Da) with the same degree of deacetylation (80%G0.29), were obtained by the method of acetic acid hydrolysis. The effect of antimicrobial activities of chitosan and acetic acid against Escherichia coli were investigated. All of the chitosan samples with MW from 5.5!10 to 15.5!10 Da had antimicrobial activities at the concentrations hig...