Association between testicular Aryl hydrocarbon Receptor levels and idiopathic male infertility: a case-control study in Iran

Increased urinary concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) and their metabolites are associated with increased risk of unexplained infertility in males. The toxicity of PAHs and dioxins are exclusively mediated through Aryl hydrocarbon Receptor (AhR). AhR overexpression contributes to the loss of normal ovarian function in polluted environments but its expression level in unexplained male infertility has remained unclear. This study aimed to compare the differential testicular levels of AhR and its interactions with other fundamental genes (ER, AR, PgR and MMP9) in a case control study. To conduct the immunohistochemical studies, 29 unexplained infertile and 10 fertile males were selected retrospectively from Jahad pathology center of Tehran from 2007 to 2009. Differential expression of AhR in Leydig, Sertoli, spermatogonia, spermatocyte, spermatid, and spermatozoa cells was determined and AhR association with other genes was compared between cases and controls. Higher levels of AhR in Leydig cells (p = 0.024), Sertoli cells (p = 0.041) and spermatid cells (p = 0.028) of infertile men have emphasized the susceptibility of these cells to environmental-induced impaired testicular functions. Moreover 85% of infertile cases showed coexpression of AhR and MMP9 in their Leydig cells (p = 0.02). Inactivation of ER, PgR and AR in AhR positive testicular cells suggests the antagonistic interactions between AhR ligands and sex steroid hormones receptors. It seems that unexplained male infertility could be originated from environmental AhR ligands which overexpress the AhR in Leydig cells, downregulate the expression of sex steroid receptors and upregulate the MMP9 in Leydig cells as the main testicular target cell of AhR ligands.     

Groundwater Source Identification and Flow Model of the Dareh-Zar Copper Mine in Central Iran by Chemo-isotopic Techniques

Mine Water and the Environment - Seepage with AMD characteristics is observed in the Dareh-Zar copper mine in central Iran and more water inrush events are expected since the pit extends below the...     

A New Cascaded Multi-level Inverter Topology with Reduced Number of Components and Charge Balance Control Methods Capabilities

In this article, a new basic unit for cascaded multi-level inverter is proposed. This inverter is able to increase the number of output voltage levels and reduces the number of power electronic devices. To generate all voltage levels at the output, five different algorithms to determine the magnitude of DC voltage sources are suggested. This inverter is compared with conventional cascaded multi-level inverters. The comparisons show that the proposed topology needs fewer DC voltage sources and power switches, less variety of the magnitude of DC voltage sources, and smaller amounts of blocked voltage by switches. As a result, the installation space and total cost of the inverter decrease. As it is impossible to use charge balance control methods for the asymmetric cascaded multi-level inverters, the developed topology based on the proposed cascaded inverter–the sub-symmetric topology with the usability of charge balance control methods–is proposed. A new algorithm is proposed to determine the magnitude of DC voltage sources. In addition, full-wave and half-wave charge balance control methods are applied in the proposed developed topology. The accurate performance of the proposed topology by applying charge balance control methods is verified through the simulation and experimental results of an 81-level sub-symmetric inverter.     

Effects of Ultrasound Amplitude on the Physicochemical Properties of Some Edible Oils

This research reports on the studied effect of the intensity of ultrasound (24 kHz) on the quality characteristics of olive oil, sesame oil, sunflower seed oil, and tallow olein. These characteristics (free acidity, peroxide value, conjugated dienes concentration, viscosity, iodine value, turbidity, color values, and melting behavior) were determined in oil samples before and after ultrasonic treatment. Changes in the oxidation parameters showed that the high‐intensity ultrasound treatment accelerated the deterioration of oils. In most cases, extra‐virgin sesame oil was most resistant to deterioration from sonicating treatments. The decreases in β‐carotene content and Hunter values revealed that ultrasound might have good potential for bleaching oils at an appropriate intensity and frequency. The differential scanning calorimeter thermograms, viscosity, and turbidity results indicated that ultrasound probably accelerates the polymerization of the oils. The present study has confirmed that some changes in the physicochemical parameters or structures of oil components had occurred. These changes depended on the sources and initial conditions of the oils as well as the intensity of the applied ultrasound.     

Multi-pinhole SPECT Imaging with Silicon Strip Detectors

Silicon double-sided strip detectors offer outstanding instrinsic spatial resolution with reasonable detection efficiency for iodine-125 emissions. This spatial resolution allows for multiple-pinhole imaging at low magnification, minimizing the problem of multiplexing. We have conducted imaging studies using a prototype system that utilizes a detector of 300-micrometer thickness and 50-micrometer strip pitch together with a 23-pinhole collimator. These studies include an investigation of the synthetic-collimator imaging approach, which combines multiple-pinhole projections acquired at multiple magnifications to obtain tomographic reconstructions from limited-angle data using the ML-EM algorithm. Sub-millimeter spatial resolution was obtained, demonstrating the basic validity of this approach.     

Determination of Pb2+ ions by a modified carbon paste electrode based on multi-walled carbon nanotubes (MWCNTs) and nanosilica

A novel carbon paste ion selective electrode for determination of trace amount of lead was prepared. Multi-walled carbon nanotubes (MWCNTs) and nanosilica were used for improvement of a lead carbon paste sensor response. MWCNTs have a good conductivity which helps the transduction of the signal in carbon paste electrode. The electrode composition of 20 wt% paraffin oil, 57% graphite powder, 15% ionophore (thiram), 5% MWCNTs, and 3% nanosilica showed the stable potential response to Pb²⁺ ions with the Nernstian slope of 29.8 (±0.2) mV decade^?1 over a wide linear concentration range of 10^?7–10^?2 mol L^?1. The electrode has fast response time, and long term stability (more than 2 months). The proposed electrode was used to determine the concentration of lead ions in waste water and black tea samples.     

Simulation of Marangoni convection effects on the hydrodynamics of liquid–liquid extraction drops

Concentration induced Marangoni convection (MC) effect has many applications in the chemical engineering processes. In this study, the MC effects have been investigated in the toluene/acetone/water (T/A/W) liquid–liquid extraction system, focusing on the mass transfer and hydrodynamics. For the first time, the VOF-CSS model has been used, and the mass transfer equation has been coupled with the hydrodynamic equations of the VOF model, using the surface tension force model of the CSS. A single mass transfer equation has been solved for the two phases, modifying the unsteady, convective, and diffusive terms based on the equilibrium distribution coefficient. The MC effect has been implemented in the CSS surface tension model with a concentration-dependent surface tension coefficient. Simulations have been carried out in 1, 1.5, and 2?mm drops in the wide range of concentration (0.9–30?g/L). Good agreements have been achieved for the concentration and reduced velocity values compared with the existing experimental data. Simulation results showed that the reduced velocity values remain almost constant for every drop diameter, in the initial concentration range from 3.7 to 30?g/L. The reacceleration time for the three drop sizes with the different initial concentrations has been obtained from the simulation results and compared. The MC effects on the axial velocity profiles and drag coefficients were also reported providing comprehensive information about the MC effects on the hydrodynamics.     

Effects of Holding Time on Thermomechanical Fatigue Properties of Compacted Graphite Iron Through Tests with Notched Specimens

In cylinder heads of compacted graphite iron (CGI), the heating and cooling cycles can lead to localized cracking due to thermomechanical fatigue (TMF). Traditionally, TMF behavior is studied by thermal cycling of smooth specimens. The resulting number of cycles to failure (N _f) constitutes a single parameter that can be used to predict actual service failures. Nevertheless, there are also some drawbacks of the conventional testing procedures, most noticeably the prolonged testing times and a considerable scatter in test results. To address these drawbacks, TMF tests were performed using notched specimens, resulting in shorter testing times with less scatter. In the case of cast iron, artificial notches do not necessarily change the TMF behavior since the inherent graphite particles behave as internal notches. Using a notch depth of 0.2 mm, the effect of prolonged holding times (HT) on TMF lifetime was studied and a clear effect was found. Extended holding times were also found to be accompanied by relaxation of compressive stresses, causing higher tensile stresses to develop in the subsequent low temperature stages of the TMF cycles. The lifetimes in notched CGI specimens can be predicted by the Paris’ fatigue crack growth model. This model was used to differentiate between the individual effects of stress level and holding times on TMF lifetime. Microstructural changes were evaluated by analyzing quantitative data sets obtained by orientation contrast microscopy based on electron backscattered diffraction (EBSD).     

A case study of energy use and economical analysis of irrigated and dryland wheat production systems

Current conventional agricultural systems using intensive energy has to be re-vitalized by new integrated approaches relying on renewable energy resources, which can allow farmers to stop depending on fossil resources. The aim of the present study was to compare wheat production in dryland (low input) and irrigated (high input) systems in terms of energy ratio, energy efficiency, benefit/cost ratio and amount of renewable energy use. Data were collected from 50 irrigated and 50 dryland wheat growers by using a face-to-face questionnaire in 2009. The results showed that the total energy requirement under low input was 9354.2 MJ ha⁻¹, whereas under high input systems it was 45367.6 MJ ha⁻¹. Total energy input consumed in both dryland and irrigated systems could be classified as direct, indirect, renewable and non-renewable energies which average in two wheat production systems were 47%, 53%, 24% and 76%, respectively. Energy ratios of 3.38 in dryland and 1.44 in irrigated systems were achieved. The benefit–cost ratios were 2.56 in dryland and 1.97 in irrigated wheat production systems. Based on the results of the present study, dry-land farming can have a significant positive effect on energy-related factors especially in dry and semi-dry climates such as Iran.