فهرست مطالب abolfazl nasiri

In this paper, resonance frequency changes in semi-dynamic wireless charging circuits and a method for improving soft switching range (ZVS) is presented. Due to the changes in the distance between the powers transmission pads, the amount of mutual inductance of the transmitter and receiver coils and as a result changes the resonant frequency of the converter. The structure of hard switching converters generally has high losses, low efficiency and limited frequency. There is an overlap between the voltage and current parameters of the non-linear elements in these converters, it makes these converters more vulnerable at high power levels. The proposed method for increasing the soft switching range in the dynamic wireless charger is presented. In order to perform better, have been presented different models of the function of keys and non-linear elements in different structures in this field. In these structures, by adding a number of additional elements to the circuit, the overlapping of the current and voltage of the switches at the moments of turning on and off is almost eliminated and are eliminated switching losses. In this article, is used LCC compensation structure. In this structure, by matching the primary inductor and capacitor in the compensator structure, the resonance frequency is smaller than the switching frequency and soft switching conditions are established in the converter. The proposed circuit is simulated in MATLAB software and are investigated the resonance frequency changes in different coupling coefficients and are presented the results.

This study investigates the compensation methods used in the wireless power transfer system in the semi-dynamic subsurface mode. Choosing the appropriate air gap for wireless power transfer requires technical considerations. Along with these, the characteristics of each coil and the compensation network structure should also be considered. In this study, the structure of common compensation networks for the power transfer system in the semi-dynamic subsurface mode was investigated and after examining the different characteristics of each compensation network, further investigation and testing was performed for the selected networks. The air gap of power transfer in the system has an inverse relationship with the coupling coefficient of the system, so that with increasing the air gap excessively, the coupling coefficient decreases significantly and the power transfer is completely cut off, so the ideal coupling coefficient range in the system with circular coils was expressed for changing the air gap. The appropriate compensation network structure for wireless power transmission in semi-dynamic mode with 3 kW power and appropriate airspace for receiving the maximum efficiency power was selected. Suitable efficiency of the converter was obtained with the selected compensator network and an approximate air distance of 40% of the diameter of the pad. The results of the research have been investigated and confirmed using PSIM software.

in this research, the analysis, investigation and design of pedestal servo-mechanics electric motor for identification of marine targets is investigated. Pedestal is one of the main parts of a radar identification, orientation and locating system. On the pedestal, antenna equipment, reflectors, processing systems, etc. Installed. The main task of the pedestal in addition to installing the equipment on it is to rotate the antenna, the reflector and change its orientation. Pedestal propulsion is supplied by electrical servomechanism or hydraulic servo mechanism. In this research, with the approach of electrical servomechanism, the design of an electric motor used in a pedal is investigated. Determining the systemic requirements of the pedal determines the speed and power characteristics of the pedal electric motor. In this study, a pedal with two degrees of freedom is investigated. Accordingly, while briefly describing electric motors, the torque motor is introduced as an electric motor suitable for use in pedal servomechanism. The experimental results confirm the accuracy of the researches.

War toxin, mustard gas, alkylating agent results in male infertility via inducing reactive oxygen species (ROS) production and DNA mutagenesis. SIRT1 and SIRT3 are multifunctional enzymes that involve in the DNA repair, oxidative stress responses. This study aim is to assess the correlation between serum levels of SIRT1, SIRT3 and both rs3758391T>C and rs185277566C>G gene polymorphisms with infertility in the war zones of Kermanshah province, Iran. In this case-control study based on the semen analysis, samples were divided into two groups infertile (n=100) and fertile (n=100). High-performance liquid chromatography (HPLC) method was used to determine the malondialdehyde level, and also a sperm chromatin dispersion (SCD) test was used to evaluate the DNA fragmentation rate. Using the colorimetric assays, superoxide dismutase (SOD) activity was measured. SIRT1 and SIRT3 protein levels were determined by using ELISA. The genetic variants of SIRT1 rs3758391T>C, and SIRT3 rs185277566C>G, were detected by polymerase chain reaction-restriction fragment length (PCR-RFLP) technique. Malondialdehyde (MDA) level and the percentage of DNA fragmentation were higher in infertile samples, but serum levels of SIRT1 and SIRT3, and SOD activity was lower in infertile compared to fertile samples (P<0.001). The TC+CC genotypes and the C allele from SIRT1 rs3758391T>C polymorphism, and CG+GG genotypes and the G allele from SIRT3 rs185277566C>G polymorphism could increase risk of infertility (P<0.05). The results of this study suggest that war toxins through the impact on genotypes, decreasing levels of SIRT1 and SIRT3 and increasing levels of oxidative stress, lead to defects in the concentration, motility and morphology of sperms and thus, infertility in men.

This article studies the design of a power modulator for driving a magnetron tube. In this design thepower modulator works with the half-bridge structure, series resonator and phase shift control method.In this scheme, by controlling the switching phase shift,the balance condition of magnetization current issatisfied and the maximum amount of core saturation current is reduced. As a result, the current stress of switches is reduced and switching and core losses are reduced. So, the size, weight and the cost of thecore of the power transformer will reduce. Also, using leakage inductance of the power transformer, the series-resonance circuit is provided soft switching condition is guaranteed. Suggested power modulator,is able to control the peak and average output power with the minimum loss. The maximum power of a microwave oven is about 1000 w and its average power is 250 W which is controlled proportionally to theinverter on-state periods. Other advantages to the proposed design are simplicity of the power circuit,decrease in the number of switching elements, decrease in the switching losses, and decrease in the leakage inductance of the power transformer. The design results have been verified through simulated ofthe PSCAD software and laboratory tests.

Reactive oxygen species (ROS) play a crucial role in etiology of DNA fragmentation and lipid peroxidationin sperm, leading to infertility in men. The silent information regulators SIRT1 and SIRT3 are members of thesirtuins protein family known to be involved in cancer genetics, aging and oxidative stress responses. The aim ofthisstudy is to determine the correlation between SIRT1 and SIRT3 with antioxidants, oxidative stress biomarkers, andDNA fragmentation in the semen of asthenoteratozoospermic and normozoospermic men. In this case-control study, after spermogram analysis the specimens were divided intotwo groups, normozospermic (n=40) and asthenoteratozoospermic (n=40), according to World Health Organization(WHO) standards. Sperm DNA fragmentation was evaluatedusing the sperm chromatin dispersion (SCD) test.Catalaseactivity was measured using the Aebi spectrophotometeric method. Total antioxidant capacity (TAC) level and superoxidedismutase (SOD) activitywere measured by using commercially available colorimetric assays. Enzyme-linkedimmune sorbent assay (ELISA) was used to measure SIRT1 and SIRT3 protein levels of seminal plasma. Malondialdehyde(MDA) level in seminal plasma was determined by high-performance liquid chromatography (HPLC). The asthenoteratozoospermic group had significantly lower catalase and SOD activities and TAC levels incomparison with the normozoospermic group (p <0.001).The percentage of DNA fragmentation and MDA level in theasthenoteratozoospermic group were remarkably higher than in the normozoospermic group. The SIRT1 and SIRT3protein levels in seminal plasmawere remarkably lower in asthenoteratozoospermic group than the normozoospermicgroup (p <0.001). The results of this study suggest that SIRT1 and SIRT3 protein levels are negatively correlated withoxidative stress and DNA fragmentation in semen. The low levels of SIRT1 and SIRT3 in asthenoteratozoospermicmen may lead to an increase in oxidative stress, DNA fragmentation, and lipid peroxidation that eventually result inimmotile and immature spermatozoa (asthenoteratozoospermia).

ancreatic β-cells recognize blood glucose changes and release insulin that is a peptide hormone responsible for stable glycemia. Diabetes, a chronic disorder of insulin insufficiency, leads to disturbed glucose homeostasis and multi-organ problems. Glucose and insulin are key markers in the follow-up and control of this disease. Mitochondrial metabolism of pancreatic beta cells is a crucial part of glucose-stimulated cascade of insulin secretion. Effective factors on β-cells mitochondrial function in production of compounds such as tricarboxylic acid intermediates, glutamate, nicotinamide adenine dinucleotide phosphate, and reactive oxygen species can have great effects on the secretion of insulin under diabetes. This review enhances our knowledge of factors influencing mitochondrial function as a key mediator of glucose-induced insulin release that accordingly will be helpful to further our understanding of the mechanisms implicated in the progressive beta cellfailure that results in diabetes.

Hemoglobinopathies are the most common single gene disorders (monogenic disorders) in the world population.  Due to specific position of Iran and the presence of multi-ethnic groups in the country, there are many varieties in the molecular genetics and clinical features of hemoglobinopathies in Iran. Hemoglobinopathies include structural variants, thalassemias, and hereditary persistence of fetal hemoglobin. In this review, we look at the common structural variants in various parts of the country along with their hematological and clinical characteristics. Also, we discuss about the burden of the thalassemias in the country, different types, complications, molecular defects and therapy.

In this paper, a new driving method is presented for a magnetron bulb utilizing a phase-shifted active clamp fly-back converter. The converter is of a booster, isolated and high gain type. The active clamping structure is used to reduce the main transistor’s voltage stress. By controlling the timing of the transistor clamp, the voltage required for the magnetron is adjusted. The main advantage of the proposed method is the simplicity of the control circuit of the magnetron lamp driver. In addition, the proposed method reduces the size, weight and price of the power transformer core. The power transformer leakage inductance has also been developed to provide a soft switching condition while reducing converter losses. The converter presents a maximum power of 1.6 kW with an average power of 400 W, by setting the timing of the activation of the driving circuit. The design results are simulated and verified by PSCAD Simulink software.

Accumulation of triglycerides in the liver i.e. steatosis, is a well-known side-effect of tamoxifen administration to patients suffering from breast cancer. Cichoriumintybus (chicory) is a plant used as traditional medicine for curing liver disorders. In this study, the effects of extract prepared from chicory roots on tamoxifen-induced liver steatosis and related biochemical factors in animal model using rats has been investigated.
Female rats of Wistar strain were divided into four groups and treated as follows; 1-Control: received vehicle; 2- Chicory root-extract treated: rats were given by gavage the aqueous chicory root extract (1 g/kg body weight/day for 14 days).3- Tamoxifen-treated: rats received tamoxifen (1 mg/kg body weight/day, for 7 days). 4- Tamoxifen爘鲢group: animals received tamoxifen (1 mg/kg body weight/day for 7 days) followed by chicory extract given by gavage (1 g/kg body weight/day for 14 days). After treatment, blood was collected by cardiac puncher, plasma was separated and plasma levels of glucose, total protein, triglyceride, cholesterol,LDL-C, HDL-C and activities of ALT, AST and ALP were measured. Liver tissues were homogenized used for measuring tissue triglyceride and histological examinations.
The data show that tamoxifen treatment caused a significant decrease in the level of serum cholesterol, HDL-C and total protein. However, serum ALT level was increased in tamoxifen-treated rats compared to controls. Increased serum ALT in tamoxifen-treated rats was recovered in rats treated with plant extract (tamoxifen爘鲢group). HDL-C and total protein levels were unaffected in rats fed chicory extracts. Tamaxifen-treated animals showed signs of liver steatosis as shown by histological examination and accumulation liver triglyceride. The steatosis markers such as accumulated triglyceride in liver was significantly reduced due to the plant extract treatments when compared to tamoxifen-group.
Dietary extract prepared from chicory roots is effective in modulation of tamoxifen-induced liver damage and steatosis.

Tamoxifen (TMX) is a synthetic drug that is widely used for treatment of breast cancer. Despite the beneficial effects of TMX, the use of this drug has several side effects such as the development of Non-Alcoholic Fatty Liver Disease (NAFLD) in the patients. Silybum marianum is the most researched plant in treatment of liver disease. In this study the effect of Silybum marianum Extract (SME) on histological and biochemical parameters in TMX-treated rats was investigated. Adult female Wistar rats were divided to four groups; 1) normal control untreated rats, 2) SME-treated rats, that received only SME in a dose of 1.6 g/kg body weight/day, oral gavage for 14 days, 3) TMX-treated rats, that received TMX in a dose of 1 mg/kg body weight/day, subcutaneously, for seven days, 4) TMX-SME-treated rats, that received TMX in a dose of 1 mg/kg body weight/day, subcutaneously, for seven days and then SME by oral gavage for 14 days. The groups were compared in terms of serum glucose, triglyceride, cholesterol, Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Alkaline Phosphatase (ALP), High-Density Lipoprotein-Cholesterol (HDL-C), Low-Density Lipoprotein-Cholesterol (LDL-C), total protein and liver triglyceride amount, and histological findings. Concentrations of HDL-C and protein decreased and activity of ALT increased in TMX group compared with the control group. The SME increased protein concentration and decreased ALT activity in TMX-SME group compared with the TMX group. Histopathological examination and triglyceride assay in liver tissues showed lipid accumulation in the TMX-treated rats and amelioration of lipid accumulation in the liver of TMX-SME-treated rats. Intake of water extract of Silybum marianum is a useful treatment for liver function in drug-induced fatty liver.