Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: S Mohammadi x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

A new model based on electric circuit theory has been introduced for modeling the radon exhalation from water to air in a sample bottle. Comparing the differential equations for radon exhalation from water to air and a hybrid electrical circuit shown that the volume of water or air, radon concentration, radon flux and solubility coefficient (dependent on temperature of water) are equivalent with capacitance, voltage across of capacitor, current and voltage gain, respectively. Then by using a hybrid electrical model total radon transfer velocity from water to air and time variation of water radon concentration in our experimental setup has been obtained. Also the variations of air radon concentration with temperature, volume of water and volume of air is obtained. The results show a good agreement with those in literatures.

Restricted access

To assess the stability and yield performance of safflower genotypes and to identify subregions within Iran, a set of experiments was conducted at six locations during 2003–2005. AMMI model analysis and some stability parameters derived from the grain yield were used. AMMI analysis showed differences between genotypes and environments and the GE interaction was highly significant, indicating that the agro-climatic environmental conditions were different, and that there was a differential response of the genotypes to the environments. The first two IPCA components of the GE interaction explained 51.5% of the GE interaction. According to the AMMI model, G16 was the most superior genotype in 15 out of 18 environments. The biplot of IPCA1 and IPCA2 showed that the six locations represent different environments, and mega-environments in Iran were identified for safflower breeding programmes. Due to the great fluctuation observed when selecting genotypes through stability parameters, it was not possible to distinguish stable genotypes clearly. In addition, when calculating these parameters high yield performance is not considered. So the Yield and Stability Index (YSI) can be recommended as a new approach to facilitate genotype selection, where genotypes with low values of YSI are the best. According to YSI the genotypes G16, G2, G9 and G1 can be selected. These genotypes were also selected using the AMMI model.

Restricted access

Background

Oxidative stress plays a critical role in the pathogenesis and progression of type 2 diabetes and diabetic-associated cardiovascular complications. This study investigated the impact of crocin combined with voluntary exercise on heart oxidative stress indicator in high-fat diet-induced type 2 diabetic rats.

Materials and methods

Rats were divided into four groups: diabetes, diabetic-crocin, diabetic-voluntary exercise, diabetic-crocin-voluntary exercise. Type 2 diabetes was induced by high-fat diet (4 weeks) and injection of streptozotocin (intraperitoneally, 35 mg/kg). Animals received crocin orally (50 mg/kg); voluntary exercise was performed alone or combined with crocin treatment for 8 weeks. Finally, malondialdehyde (MDA), activity of antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were measured spectrophotometrically.

Results

Treatment of diabetic rats with crocin and exercise significantly decreased the levels of MDA (p < 0.001) and increased the activity of SOD, GPx, and CAT compared with the untreated diabetic group. In addition, combination of exercise and crocin amplified their effect on antioxidant levels in the heart tissue of type 2 diabetic rats.

Conclusion

We suggest that a combination of crocin with voluntary exercise treatment may cause more beneficial effects in antioxidant defense system of heart tissues than the use of crocin or voluntary exercise alone.

Restricted access

Ectomycorrhizal fungi are able to form symbiotic associations with tree roots, and therefore, plants gain different benefits. On metal-contaminated soils, these fungi may improve plant fitness through an enhanced nutrition or by reducing toxicity of the metals. Agaricus bisporus, an edible fungus has been noted to grow in large numbers under Pistacia vera plantations in orchards of Kerman, Iran, indicating that it may form ectomycorrhiza with the tree. This research describes the responses of this fungus to heavy metals in solid and liquid MMN media. The fungus was grown in vitro in liquid and solid cultures for 3 weeks on five different concentrations (0, 15, 30, 45, 60 ppm) of five heavy metals (Cu, Zn, Ni, Co, Mn) as sulphate and the effect of these metal on radial growth, biomass production and metal content of fungal biomass were determined. The result showed there was a strong variation in metal tolerance, so that Agaricus bisporus was more tolerant to Mn than other metals, while the reverse was true for Ni, so that the fungus had an increased growth in the presence of low concentrations of Co, Mn, and Zn, but Ni greatly inhibited increase in biomass and colony diameter even at concentrations as low as 15 mg/l.

Restricted access

Twenty cyanobacterial strains of the genus Tolypothrix, including 15 strains of T. tenuis, three strains of T. ceylonica, and one each of T. nodosa and T. bouteillei, that were collected from various agro-ecological regions of India were evaluated for important parameters related to nitrogen fixing potential, such as acetylene reduction activity, total protein and chlorophyll content. Distinct differences were observed in nitrogen fixing potential at both inter- and intraspecific levels. The T. tenuis strains, in general, exhibited superior nitrogen fixing ability as compared to strains belonging to other species. A statistical procedure based on simultaneous consideration of performances of various strains with respect to different parameters under study aided in identification of three highly promising T. tenuis accessions, namely ARM586, ARM75 and ARM460, for potential exploitation as biofertilisers.

Restricted access