Quantitative evaluation of polymer gel dosimeters by broadband ultrasound attenuation

Ultrasound has been examined previously as an alternative readout method for irradiated polymer gel dosimeters, with authors reporting varying dose response to ultrasound transmission measurements. In this current work we extend previous work to measure the broadband ultrasound attenuation (BUA) response of irradiated PAGAT gel dosimeters, using a novel ultrasound computed tomography system

Three-dimensional cohesive fracture modeling of non-planar crack growth using adaptive FE technique

AbstractIn this paper, the three-dimensional adaptive finite element modeling is presented for cohesive fracture analysis of non-planer crack growth. The technique is performed based on the Zienkiewicz–Zhu error estimator by employing the modified superconvergent patch recovery procedure for the stress recovery. The Espinosa–Zavattieri bilinear constitutive equation is used to describe the cohesive tractions and displacement jumps. The 3D cohesive fracture element is employed to simulate the crack growth in a non-planar curved pattern. The crack growth criterion is proposed in terms of the principal stress and its direction. Finally, several numerical examples are analyzed to demonstrate the validity and capability of proposed computational algorithm. The predicted crack growth simulation and corresponding load-displacement curves are compared with the experimental and other numerical results reported in literature

New Model Reference Adaptive System Speed Observer for Field-Oriented Control Induction Motor Drives Using Neural Networks

One of the primary advantages of field-oriented controlled induction motor for high performance application is the capability for easy field weakening and the full utilization of voltage and current rating of the inverter to obtain a wide dynamic speed rangeThis paper describes a Model Reference Adaptive System (MRAS) based scheme using Artificial Neural Network (ANN) for online speed estimation of sensorless vector controlled induction motor drive. The proposed MRAS speed observer uses the current model as an adaptive model. The neural network has been then designed and trained online by employing a back propagation network (BPN) algorithm. The estimator was designed and simulated in Matlab/Simulink. Simulation result shows a good performance of speed estimator. The simulation results show good performance in various operating conditions. Also Performance analysis of speed estimator with the change in resistances of stator is presented. Simulation results show this estimator robust to parameter variations especially resistances of stator

Evaluation of drought tolerance indices among some winter rapeseed cultivars

The main purpose of this study was to evaluate the effect of drought stress on seed yield of some winter rapeseed cultivars and to study relevant drought tolerance indices, along with identifying resistant cultivars to drought stress. Plant materials were sown in split plot arrangement based on a randomized complete blocks design, at Islamic Azad University of Tabriz research field. Three drought stress levels which include 80, 130, and 180 mm water evaporation from class A pan were considered as the main factor levels, while seven winter rapeseed cultivars which include Licord, Okapi, Opera, S.L.M.046, Zarfam, Modena, and Talaye were arranged to sub plots. Studied quantitative drought tolerance indices were, tolerance index (TOL), mean productivity (MP), stress susceptibility index (SSI), stress tolerance index (STI), geometric mean productivity (GMP), yield index (YI), yield stability index (YSI), and percentage of yield reduction (%Reduction). The yield stability analysis of the studied cultivars was done by GGE biplot method. According to the results derived from principal component analysis and regarding evaluation of correlation coefficients among indices, STI and GMP were selected as the two superior indices for identifying drought resistant cultivars. Three dimensional scatter plots based on STI and GMP indices showed that Licord and Talaye were the most suitable cultivars, and were situated in group, A. In addition, Modena and Zarfam were identified as sensitive and resistant to drought stress, respectively.Key words: Brassica napus L, principal component analysis, drought stress, drought tolerance indices, stability analysis (GGE biplot), 3D scatter plot

Magnetic resonance imaging of human-derived amniotic membrane stem cells using PEGylated superparamagnetic iron oxide nanoparticles

Objective: The label and detection of cells injected into target tissues is an area of focus for researchers. Iron oxide nanoparticles can be used to label cells as they have special characteristics. The purpose of this study is to examine the effects of iron oxide nanoparticles on human-derived amniotic membrane stem cell (hAMCs) survival and to investigate the magnetic properties of these nanoparticles with increased contrast in magnetic resonance imaging (MRI). Materials and Methods: In this experimental study, we initially isolated mesenchymal stem cells from amniotic membranes and analyzed them by?ow cytometry. In addition, we synthesized superparamagnetic iron oxide nanoparticles (SPIONs) and characterized them by various methods. The SPIONs were incubated with hAMCs at concentrations of 25-800 μg/mL. The cytotoxicity of nanoparticles on hAMCs was measured by the MTT assay. Next, we evaluated the effectiveness of the magnetic nanoparticles as MRI contrast agents. Solutions of SPION were prepared in water at different iron concentrations for relaxivity measurements by a 1.5 Tesla clinical MRI instrument. Results: The isolated cells showed an adherent spindle shaped morphology. Polyethylene glycol (PEG)-coated SPIONs exhibited a spherical morphology. The average particle size was 20 nm and magnetic saturation was 60 emu/g. Data analysis showed no signifcant reduction in the percentage of viable cells (97.86 ± 0.41) after 72 hours at the 125 μg/ml concentration compared with the control. The relaxometry results of this SPION showed a transverse relaxivity of 6.966 (μg/ml.s)-1 Conclusion: SPIONs coated with PEG used in this study at suitable concentrations had excellent labeling efficiency and biocompatibility for hAMCs

Mutagenic effects of nanosilverconsumer products: A new approach to physicochemical properties

Serious concerns have been expressed about potential health risks of Nano silver containing consumer products (AgNPs) therefore regulatory health risk assessment on such nanoparticles has become mandatory for the safe use of AgNPsinbiomedicalproducts with special concerns to the mutagenic potentials. In this study, we examined the inhibitory and mutagenicity effects of AgNPs in three different sizes of three colloidal AgNPs by Minimal Inhibitory concentration (MIC), Minimal Bactericidal Concentration (MBC) and Bacterial Reverse Mutation Assay (Ames test).All samples were characterized by transmission electron microscopy (TEM), X-Ray Diffraction (XRD) and Dynamic Light Scattering (DLS). DLS analysis showed lack of large agglomeration of the AgNPs and TEM results showed the spherical AgNPswith the average sizes of 15, 19.6, 21.8 nms. Furthermore the XRD analysis showed the crystalline samples with a face centered cubic structure of pure silver.AmestestresultsonColloidal silver nanoparticles showed lack of any mutation in TA100, TA98, YG1029S. typhymuriumstrains. In addition colloidal silver nanoparticles reduced the mutation ratesin all three strains in a concentration dependent manner.This finding creates a new issue in the possible antimutagenic effects of colloidal AgNPsas a new pharmaceutical productwhich should be consideredinfuture studiesby focusing onthephysicochemical properties of AgNPs. © 2015 by School of Pharmacy Shaheed Beheshti University of Medical Sciences and Health Services

Laboratory Evaluation of Five Chitin Synthesis Inhibitors Against the Colorado Potato Beetle, Leptinotarsa decemlineata

Results of laboratory experiments are reported that tested the effects of five chitin synthesis inhibitors, diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron. on second instars of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Crysomelidae), originally collected from potato fields of Bostanabaad, a town 66 km southeast of Tabriz, Iran. In bioassays, the larvae were fed potato leaves dipped in aqueous solutions containing chitin synthesis inhibitors. The mortalities and abnormalities of the treated larvae were recorded 72 hours after treatments. LC50 values were 58.6, 69.6, 27.3, 0.79 and 81.4 mg ai/ L for diflubenzuron, cyromazine, lufenuron, hexaflumuron and triflumuron, respectively. Compared with phosalone, which is one of the common insecticides used for controlling this pest in Iran, lufenuron and hexaflumuron seem to be much more potent, and if they perform equally well in the field, they would be suitable candidates to be considered as reduced risk insecticides in management programs for L. decemlineata due to much wider margin of safety for mammals and considerably fewer undesirable environmental side effects

Gaining comprehensive data about sexual knowledge through surveys

Background: Delivery of sexual health services rely on rigorous facts extracted from surveys, but often those facts cannot be available due to the lack of culturally-sensitive questionnaires. Objective: our aim was to show the validity and reliability of the Persian version of the Acquisition of Sexual Information Test (ASIT), a measure selected due to its assemblages with Iranian culture. Materials and Methods: Forward-backward procedure was applied to translate the questionnaire. Cross-sectional study was carried out and psychometric properties of the Iranian version were tested in a thirty sample of reproductive-age women. Face validity was assessed by qualitative and quantitative methods. Content validity was also assessed by calculating two quantitative indicators as content validity index (CVI) and content validity ratio (CVR). Reliability was assessed by test-retest analyses. Results: Impact score was 1.5, the majority of participants (83.3%) stated that the overall level of questionnaire was high but some of the questions were irrelevant to sexual knowledge. Many questions (90%) gained a CVR less than 0.56, and all of them gained CVIs lower than 0.7. Correlation in test-retest reliability was 0.85

Investigation of relationship between social capital and quality of life in female headed families

Background: Although most studies on female-headed families focus on women's access to social support, the associations between social capital and quality of life in these families are unclear in many societies (such as Iran). This study aimed to determine the associations between social capital and quality of life in Iranian female headed families. Methods: This cross-sectional study was performed on 152 female-headed households supported by Tehran Municipality, district 9 from April 2011 to July 2012. Convenience sampling was employed. Data were collected using demographic questionnaire, the Iranian version of World Health Organization Quality of Life, and the Word Bank Social Capital. Descriptive and multiple regression methods were used to analyze the data. Results: The mean±SD age of participants was 50.8±13.8 years. Findings revealed that in quality of life, the domains of environment health and social relation received the lowest (9.87 ± 2.41) and the highest (12.61 ±3.43) scores respectively; and with respect to social capital, membership in groups and social trust had the least (19.61 ± 17.11) and the most (51.04 ± 17.37) scores, respectively. The multiple regression model revealed a significant positive association between total score of the quality of life and the total score for the social capital (p < 0.001). Conclusion: Findings suggest that quality of life of female-headed families and social capital domains are strongly related. This means that by improving the social capital, women's life can also be improved

Reconstructing 3D x-ray CT images of polymer gel dosimeters using the zero-scan method

In this study x-ray CT has been used to produce a 3D image of an irradiated PAGAT gel sample, with noise-reduction achieved using the ‘zero-scan’ method. The gel was repeatedly CT scanned and a linear fit to the varying Hounsfield unit of each pixel in the 3D volume was evaluated across the repeated scans, allowing a zero-scan extrapolation of the image to be obtained. To minimise heating of the CT scanner’s x-ray tube, this study used a large slice thickness (1 cm), to provide image slices across the irradiated region of the gel, and a relatively small number of CT scans (63), to extrapolate the zero-scan image. The resulting set of transverse images shows reduced noise compared to images from the initial CT scan of the gel, without being degraded by the additional radiation dose delivered to the gel during the repeated scanning. The full, 3D image of the gel has a low spatial resolution in the longitudinal direction, due to the selected scan parameters. Nonetheless, important features of the dose distribution are apparent in the 3D x-ray CT scan of the gel. The results of this study demonstrate that the zero-scan extrapolation method can be applied to the reconstruction of multiple x-ray CT slices, to provide useful 2D and 3D images of irradiated dosimetry gels