Sharif Digital Repository

To mitigate environmental pollution and food contamination caused by inappropriate and excessive herbicide usage, most potent herbicides should be screened to control rice weeds. A research trial was executed for assessing the comparative efficacy of different herbicides to control rice field weeds and to evaluate the toxicity on rice under normal (distilled water) as well as different salinity levels (4 and 8 dS m-1). The study was designed to select the most potent herbicide and its appropriate dose for weed control of rice crop in coastal areas. Fourteen herbicidal treatments were included weed free crop, Pretilachlor (0.25, 0.50, 0.375 and 0.75 kg a.i. ha-1), Propanil + Thiobencarb (0.6... 

Uptake rate of 133Cs, at three different concentrations of CsCl, by Calendula alata, Amaranthus chlorostachys and Chenopodium album plants grown outdoors was studied. These plants grow abundantly in semi-arid regions and their varieties exist in many parts of the world. When exposed to lowest Cs concentration 68 percent Cs was remediated by Chenopodium album. 133Cs accumulation in shoots of Amaranthus chlorostachys reached its highest value of 2146.2mgkg -1 at a 133Cs supply level of 3.95mgl -1 of feed solution. The highest concentration ratio value was 4.89 for Amaranthus chlorostachys, whereas for the other tests it ranged from 0.74 to 3.33. Furthermore uptake of 133Cs by all three species... 

This study was focused on the heavy metal (Ni, Co, Mo, V, Mn, Fe, W and Zn) tolerance of fungi strains Aspergillus niger, Aspergillus foetidus and Penicillium simplicissimum. Aspergillus niger was exposed to a mixture of Mo, V and Mn at a mass ratio of 1:2:6 as approximately present in the spent refinery processing catalyst. This study highlights the adaptation of fungi strains to Tungsten and Vanadium to high concentration. The effect of different metals and metal concentration on different strains of fungi was evaluated. Results showed that Ni was one of the most toxic metals for strains of Aspergillus and Penicillium. Aspergillus foetidus was the least tolerant, in particular for Ni, Co... 

In this paper, we discuss modeling issues of the Parkinson's tremor. Through the work we have employed physiological structure as well as functioning of the parts in brain that are involved in the disease. To obtain more practical similarity, random behaviors of the connection paths are also considered. Medication or treatment of the disease both by drug prescription and electrical signal stimulation are modeled based on the same model introduced for the disease itself. Two new medication strategies are proposed based on the model to reduce the side effects caused by the present drug prescription. © 2005 Elsevier Ltd. All rights reserved  

A signaling pathway is a sequence of proteins and passenger molecules that transmits information from the cell surface to target molecules. Understanding signal transduction process requires detailed description of the involved pathways. Several methods and tools resolved this problem by incorporating genomic and proteomic data. However, the difficulty of obtaining prior knowledge of complex signaling networks limited the applicability of these tools. In this study, based on the simulation of signal flow in signaling network, we introduce a method for determining dominant pathways and signal response to stimulations. The model uses topology-weighted transit compartment approach and comprises... 

The aim of this study was to quantify the DNA damage induced in a clinical megavoltage photon beam at various depths in and out of the field. MCNPX was used to simulate 10 × 10 and 20 × 20 cm2 10-MV photon beams from a clinical linear accelerator. Photon and electron spectra were collected in a water phantom at depths of 2.5, 12.5 and 22.5 cm on the central axis and at off-axis points out to 10 cm. These spectra were used as an input to a validated microdosimetric Monte Carlo code, MCDS, to calculate the RBE of induced DSB in DNA at points in and out of the primary radiation field at three depths. There was an observable difference in the energy spectra for photons and electrons for points... 

Among High Level Natural Radiation Areas (HLNRAs) all over the world, the northern coastal city of Ramsar has been considered enormously important. Many studies have measured environmental radioactivity in Ramsar, however, no survey has been undertaken to measure concentrations in the diets of residents. This study determined the 226Ra activity concentration in the daily diet of people of Ramsar. The samples were chosen from both normal and high level natural radiation areas and based on the daily consumption patterns of residents. About 150 different samples, which all are local and have the highest consumption, were collected during the four seasons. In these samples, after washing and... 

Ramsar, in the north of Iran by the Caspian Sea, has been known for the highest natural radiation background on Earth due to the local geology and hydrogeology. The residents and visitors use the hot springs that distribute the natural radionuclides especially 226Ra and its decay products in the areas. Many studies have been undertaken to measure the absorbed dose rate in Ramsar's air, however, no survey has been done to assess public internal exposure from ingestion of natural radionuclides, such as, a broad survey for 226Ra was conducted in foodstuffs and drinking water. This study presents the results of public annual activity intake (Bq) and effective dose (μSv) from ingestion of 226Ra...