Other industries or strategic installations cities after the industrialization process, a large p... more Other industries or strategic installations cities after the industrialization process, a large percentage of urban land use, consciously or unconsciously to have been allocated. Investigation and detection of black spots and dangerous in systems and processes to prevent accidents is of particular importance. Risks in the project, are unknown events that may happen in the event of a negative or positive impact on project objectives is effective. Each event has specific causes and consequences are distinguishable. The consequences of these events directly in time, cost and quality. Therefore, effective project risk identification and to determine the effect of special importance. Organizations should be able to use a variety of methods to assess the risk of one or a combination of the select few. This article introduces the risk assessment and FMEA methodology has been focused on the process of doing that.
Development of inexpensive and simple culture media is always favorable for recombinant protein o... more Development of inexpensive and simple culture media is always favorable for recombinant protein over-expression in E. coli. The effects of medium composition on the production of recombinant human granulocyte-colony stimulating factor (rh-GCSF) were investigated in batch culture of E. coli BL21 (DE3) [pET23a-hgcsf]. First, the optimum medium for production of rh-GCSF was determined; and, then it was shown that mixture of amino acid addition at induction time, which was determined on the basis of amino acids frequency in the recombinant protein, increases recombinant protein expression level significantly. Furthermore, the effect of glucose concentration on productivity of rh-GCSF was investigated; 20 g/l of glucose will result in maximum attainable biomass and rh-GCSF in this process. At optimum conditions, a cell dry weight of 10.5 g/l, an expression level of about 35% of total cellular protein, rh-GCSF concentration of 1.75 +/- 0.1 g/l, and overall rh-GCSF yield of 165 +/- 5 mg/g were obtained.
Iranian Journal of Allergy Asthma and Immunology, 2004
Nutrition is an important factor that influences immunity, and nutritional deficiencies can impai... more Nutrition is an important factor that influences immunity, and nutritional deficiencies can impair resistance to infections. Malnutrition is the most common cause of immunodeficiency worldwide. Trace elements such as zinc, selenium, iron, and copper can influence several components of immunity. Primary antibody deficiency disorders are a group of disorders characterized by an unusual susceptibility to infections and malnutrition. Impaired nutritional status has been reported in immunodeficient patients. The aim of this study was to determine anthropometric indices and trace elements status in these patients. Thirty-eight children (28 males, 10 females, aged 2-18 years) with primary antibody deficiency referring to Children's Medical Center of Tehran University of Medical Science were enrolled in this research. Primary immunodeficiency disorders consisting of CVID, XLA, IgA deficiency, IgG subclass deficiency, and hyper IgM were assessed. Anthropometric indices, comprised of height, weight that were measured and body mass index (BMI) was calculated. Height-for-age (HAZ), weight-for-height (WHZ) and weight-for-age (WAZ) were determined according to Z-score to study mild, moderate and severe malnutrition. Serum copper, zinc, selenium and iron levels were measured by an atomic absorption spectrometer. The most common disorders were CVID 52.5% and X-linked agammaglobulinaemia 27.5%. Based on BMI measurements 21.1% of patients had malnutrition. According to HAZ, 13.2%, 13.2% and 36.8% had severe, moderate and mild malnutrition, respectively. According to WAZ, 10.5%, 18.4% and 28.6% had severe, moderate and mild malnutrition, respectively. Regarding to WHZ, 14.3% and 28.6% had moderate and mild malnutrition, respectively. Low selenium levels and high copper levels were observed in 37.5% and 70.3%, respectively. Anthropometric data showed that the frequency of malnutrition in these patients was higher than the CDC standard. Low serum selenium levels and high serum copper levels were observed, suggesting further research is needed on these parameters. Most of the patients had serum zinc and iron levels within the normal range. It is recommeded that clinical immunologists and nutritionists should make a collective effort to provide these patients with standard or specialized diets so as to decrease the risk of infection.
The present study deals with preparation and optimization of a novel chitosan hydrogel-based matr... more The present study deals with preparation and optimization of a novel chitosan hydrogel-based matrix by suspension crosslinking method for controlled release of Depo-Medrol. The controlled release of Depo-Medrol for effective Rheumatoid arthritis disease has become one of the imperative fields in a drug delivery system. In this context, it was paid to optimize loading circumstances by experimental design and also study on release kinetic of Depo-Medrol entrapped in the chitosan matrix in order to reach maximal efficiency for drug loading. The optimum concentrations of the chitosan (2.5 g), glutaraldehyde (3.05 µl) and Depo-Medrol (0.1 mg) were set up to achieve the highest value of drug loaded and the most sustained release from the chitosan matrix. In-vitro monitoring of drug release kinetic using high-performance liquid chromatography (HPLC) showed that 73% of the Depo-Medrol released within 120 min, whereas remained drug was released during the next 67 h. High correlation between first order and Higuchi's kinetic models indicates a controlled diffusion of Depo-Medrol through the surrounding media. Moreover, recovery capacity more than 82% and the entrapment efficiency 58-88% were achieved at the optimal conditions. Therefore, the new synthesized Depo Medrol- chitosan is an applicable appliance for arthritis therapy by slow release mechanism. This article is protected by copyright. All rights reserved.
Trauma still stands atop of the list of emergencies. Transfer of these patients via Emergency Med... more Trauma still stands atop of the list of emergencies. Transfer of these patients via Emergency Medical Services (EMS) dispatch is critical with regard to importance of timing. This aspect has achieved greater importance due to population increase and telephone triage. We aimed to decrease unnecessary Emergency Medical Services (EMS) missions via a computer program designed for an algorithmic approach for trauma care by nurses involved in EMS, to help them evaluate the case more accurately. We named our program "Trauma Dispatch Algorithm". First, the most common chief complaints regarding traumatic events were chosen from searching all the calls in December 2008 recorded in Tehran, Iran's EMS center; and then an algorithm approach was written for them. These algorithms were revised by three traumatologists and emergency medicine specialists, after their approval the algorithms were evaluated by EMS dispatch center for their practicality. Finally all data were turned into computer software. The program was used at the Tehran EMS center; 100 recorded calls assessed with each system were selected randomly. They were evaluated by another traumatologist whether it was necessary to send a team to the site or not. The age average was 26 years in both groups. The "trauma dispatch algorithm" was significantly effective in reducing the unnecessary missions of EMS by 16% (from 42% to 26%) (P = 0.005). This program was effective in reducing unnecessary missions. We propose the usage of this system in all EMS centers.
Electrodeposition is known to be proper for separation and preconcentration of extremely low conc... more Electrodeposition is known to be proper for separation and preconcentration of extremely low concentrations of analytes from the bulk sample which is instrumentally very simple. In the present research, a combination of electrodeposition with arc atomic emission spectrometry (ED-AAES) method has been developed in order to improve the analytical performance of this spectrometry technique. The results show that sensitivity and detection limits by using ED-AAES were improved 1000-2000 folds over those of normal arc atomic emission spectrometry in determination of the selected elements. The detection limits for measurement of Ni, Cr and Pb were 2.56, 3.05 and 2.11 µg L − 1 for monodeposition and 3.31, 3.72 and 3.25 µg L − 1 for simultaneously deposition, respectively. The precision of determination was in the range of 2-4% RSD. Typical calibration graphs for these elements were linear up to 100 µg L − 1 , depending on the element and matrix. Application of this technique was also tested on determination of the studied elements in an electroplating plant's waste water. The accuracy of technique was verified by comparing the results of the waste water analysis with those of electrothermal atomic absorption spectroscopy as a reference standard method. The obtained results show that the combined technique (ED-AAES) has been progressed substantially toward the ultimate goal of direct interference-free determination of trace analysis in complex samples by AAES.
ABSTRACT Objective: Children, due to their great parental dependency, are amongst the cases that ... more ABSTRACT Objective: Children, due to their great parental dependency, are amongst the cases that should receive preoperatively medication to reduce their fear and anxiety. The objective of this study was to compare the efficacy of rectal diazepam and midazolam for this purpose in pediatric patients scheduled for elective surgery.Material & Methods: 60 children, aged between 1 and 6 years, scheduled for elective surgery, were included in this double blind, randomized controlled trial. Patients were randomly allocated into three equal groups. Patients in midazolam and diazepam groups received the drugs 0.3 mg/kg and 0.5 mg/kg respectively (in normal saline at a final volume of 2.5 ml) and placebo group received only 2.5 ml of normal saline 20 min before arriving operation room through rectal applicator. Sedation and anxiety scores at the time of separation from their parents before arriving operating room were recorded for all groups.Findings: There was a significant reduction in anxiety level in midazolam and diazepam groups as compared to placebo group (P<0.001). Sedation rate was 65% for midazolam, 60% for diazepam, and 15% for placebo group (P=0.007). There were no significant changes in hemodynamic parameters in the three study groups.Conclusion: With respect to effective anxiolytic and sedative activity, rectal midazolam (0.3 mg/Kg) and diazepam (0.5 mg/Kg) can be used as an anesthetic premedicant for children at pre-operative period and their use is safe regarding hemodynamic variables and related side-effects.
ObjectiveClonidine is an α2-agonist which is used as a sedative premedication in children. There ... more ObjectiveClonidine is an α2-agonist which is used as a sedative premedication in children. There are conflicting results in the published literature about the effect of clonidine on the incidence of post operative nausea and vomiting (PONV). We therefore decided to evaluate the effect of oral clonidine given preoperatively on the incidence of PONV in children after appendectomy.MethodsSixty children, 5-12 years old, classified as American Society of Anesthesiologists physical status I and II, who were scheduled for appendecectomy were enrolled in this randomized double blinded clinical trial. Patients were randomly assigned into two groups of 30 patients. Patients in clonidine group were given 4 µg.kg -1 clonidine in 20 cc of apple juice and patients in control group were given only 20 cc of apple juice 1 hour before transporting to operating room. The protocol of general anesthesia and postoperative analgesia was the same for two groups. Incidence of PONV and antiemetic usage of patients were assessed during 0-24 hours after anesthesia.FindingsThe patients’ characteristics were similar in two groups. Patients who had received clonidine had significantly less episodes of PONV and also less rescue antiemetic usage than patients in control group.ConclusionWe showed that oral clonidine at a dose of 4 µg.kg -1 administered preoperatively is associated with a reduced incidence of postoperative vomiting in children who have undergone appendectomy.
The grain growth kinetics of an extruded fine-grained Mg–9Gd–4Y–0.4Zr (wt%) alloy was investigate... more The grain growth kinetics of an extruded fine-grained Mg–9Gd–4Y–0.4Zr (wt%) alloy was investigated by static annealing in the temperature range of 673–773 K. In addition to the microstructural evolution, textural evolution of the material was also studied during high temperature exposure. The material revealed an unusual basal texture in the extruded condition which was weakened after annealing. The material behavior can be divided into two temperature regimes, namely from 673 to 723 K and from 723 to 773 K. According to the obtained data, although the material shows superior thermal stability in comparison with the conventional Mg alloys, it loses most of its resistance to grain growth at temperatures higher than 673 K. It was observed that although the Mg3(Gd,Y) precipitates have sufficient thermal stability to restrict grain growth, significant grain growth occurs at the highest temperatures where increased mobility of the grain boundaries seems to be dominant. However, there is ...
Case Studies in Engineering Failure Analysis, 2015
ABSTRACT Two packing cups of the second stage cylinders of the polyethylene hyper compressors fai... more ABSTRACT Two packing cups of the second stage cylinders of the polyethylene hyper compressors failed after service life of about three months. In this paper, microstructural investigations and fracture surface studies are presented for failure analysis of the damaged parts. Moreover, the stress analysis is performed by using fatigue striations to evaluate the principal stress components of the lube oil ducts. It is shown that although the design of packing cup elements is very important, the quality of the finished surfaces, wear resistance and mechanical properties of the selected material must be considered to increase the fatigue life of critical parts of the hyper compressor.
Background: Myocarditis is inflammation of the cardiac myocytes. In the first 6 months of life, m... more Background: Myocarditis is inflammation of the cardiac myocytes. In the first 6 months of life, myocarditis is slow-progressing and sudden death is common. It should not be forgotten that these patients can have intrauterine myocarditis. Case Presentation: A 4-month-old male patient had fast breathing and cyanosis during crying in the last month. At admission, we found tachypnea and hypoxia in his physical examination, and cardiomegaly on the chest radiogram. Subsequently, dilatation of left ventricle and left atrium, systolic dysfunction of left ventricle, and mitral valve regurgitation were found in echocardiography. The patient was diagnosed with myocarditis. We were informed that he had a twin brother, so we evaluated the second baby too. Similar but less severe findings were obtained in the echocardiographic examination of the twin brother, who had normal findings in physical examination. Infectious and metabolic scanning tests were performed on both patients. The underlying ca...
Eastern Mediterranean health journal = La revue de santé de la Méditerranée orientale = al-Majallah al-ṣiḥḥīyah li-sharq al-mutawassiṭ
A study in Babol, Islamic Republic of Iran, used a questionnaire to gather information on knowled... more A study in Babol, Islamic Republic of Iran, used a questionnaire to gather information on knowledge about oral cancer and its risk factors and to evaluate the efficacy of an educational brochure. From a community sample of 400 people, 76.0% had no knowledge of oral cancer. Mean knowledge score before the education intervention was 1.47 (standard deviation 3.40) out of 10. Knowledge about oral cancer was not associated with age, sex or education level but urban residents had better knowledge than rural residents. Mean knowledge score improved significantly by 5.92 (SD 3.30) at 1 month after the intervention among the 226 respondents who had read the brochure.
ABSTRACT The microstructure and high-temperature shear strength of the Mg–10Gd–3Y–1.2Zn–0.5Zr all... more ABSTRACT The microstructure and high-temperature shear strength of the Mg–10Gd–3Y–1.2Zn–0.5Zr alloy were investigated in the as-cast and aged (T6) conditions. The shear yield stress (SYS), and ultimate shear strength (USS) were measured by the shear punch test (SPT) in the temperature range of 25–300 �C. The results showed that both USS and SYS of the as-cast alloy are greatly improved after the T6 aging treatment at all test temperatures. However, the variation of strength with temperature showed different trends for the as-cast and aged conditions of the material. The USS of the aged alloy decreased monotonically from 315 MPa at room temperature, to 282 MPa at 300 �C. This was in contrast to the USS values of the as-cast alloy, which first decreased from 270 MPa at room temperature to 255 MPa at 150 �C, and then increased with temperature, passing through maximum values of 263 MPa at 250 �C. The mechanism by which the as-cast and aged alloys show different shear behavior with increasing test temperature was discussed and related to the role of precipitates and the long period stacking ordered (LPSOs) in high temperature strengthening.
Other industries or strategic installations cities after the industrialization process, a large p... more Other industries or strategic installations cities after the industrialization process, a large percentage of urban land use, consciously or unconsciously to have been allocated. Investigation and detection of black spots and dangerous in systems and processes to prevent accidents is of particular importance. Risks in the project, are unknown events that may happen in the event of a negative or positive impact on project objectives is effective. Each event has specific causes and consequences are distinguishable. The consequences of these events directly in time, cost and quality. Therefore, effective project risk identification and to determine the effect of special importance. Organizations should be able to use a variety of methods to assess the risk of one or a combination of the select few. This article introduces the risk assessment and FMEA methodology has been focused on the process of doing that.
Development of inexpensive and simple culture media is always favorable for recombinant protein o... more Development of inexpensive and simple culture media is always favorable for recombinant protein over-expression in E. coli. The effects of medium composition on the production of recombinant human granulocyte-colony stimulating factor (rh-GCSF) were investigated in batch culture of E. coli BL21 (DE3) [pET23a-hgcsf]. First, the optimum medium for production of rh-GCSF was determined; and, then it was shown that mixture of amino acid addition at induction time, which was determined on the basis of amino acids frequency in the recombinant protein, increases recombinant protein expression level significantly. Furthermore, the effect of glucose concentration on productivity of rh-GCSF was investigated; 20 g/l of glucose will result in maximum attainable biomass and rh-GCSF in this process. At optimum conditions, a cell dry weight of 10.5 g/l, an expression level of about 35% of total cellular protein, rh-GCSF concentration of 1.75 +/- 0.1 g/l, and overall rh-GCSF yield of 165 +/- 5 mg/g were obtained.
Iranian Journal of Allergy Asthma and Immunology, 2004
Nutrition is an important factor that influences immunity, and nutritional deficiencies can impai... more Nutrition is an important factor that influences immunity, and nutritional deficiencies can impair resistance to infections. Malnutrition is the most common cause of immunodeficiency worldwide. Trace elements such as zinc, selenium, iron, and copper can influence several components of immunity. Primary antibody deficiency disorders are a group of disorders characterized by an unusual susceptibility to infections and malnutrition. Impaired nutritional status has been reported in immunodeficient patients. The aim of this study was to determine anthropometric indices and trace elements status in these patients. Thirty-eight children (28 males, 10 females, aged 2-18 years) with primary antibody deficiency referring to Children's Medical Center of Tehran University of Medical Science were enrolled in this research. Primary immunodeficiency disorders consisting of CVID, XLA, IgA deficiency, IgG subclass deficiency, and hyper IgM were assessed. Anthropometric indices, comprised of height, weight that were measured and body mass index (BMI) was calculated. Height-for-age (HAZ), weight-for-height (WHZ) and weight-for-age (WAZ) were determined according to Z-score to study mild, moderate and severe malnutrition. Serum copper, zinc, selenium and iron levels were measured by an atomic absorption spectrometer. The most common disorders were CVID 52.5% and X-linked agammaglobulinaemia 27.5%. Based on BMI measurements 21.1% of patients had malnutrition. According to HAZ, 13.2%, 13.2% and 36.8% had severe, moderate and mild malnutrition, respectively. According to WAZ, 10.5%, 18.4% and 28.6% had severe, moderate and mild malnutrition, respectively. Regarding to WHZ, 14.3% and 28.6% had moderate and mild malnutrition, respectively. Low selenium levels and high copper levels were observed in 37.5% and 70.3%, respectively. Anthropometric data showed that the frequency of malnutrition in these patients was higher than the CDC standard. Low serum selenium levels and high serum copper levels were observed, suggesting further research is needed on these parameters. Most of the patients had serum zinc and iron levels within the normal range. It is recommeded that clinical immunologists and nutritionists should make a collective effort to provide these patients with standard or specialized diets so as to decrease the risk of infection.
The present study deals with preparation and optimization of a novel chitosan hydrogel-based matr... more The present study deals with preparation and optimization of a novel chitosan hydrogel-based matrix by suspension crosslinking method for controlled release of Depo-Medrol. The controlled release of Depo-Medrol for effective Rheumatoid arthritis disease has become one of the imperative fields in a drug delivery system. In this context, it was paid to optimize loading circumstances by experimental design and also study on release kinetic of Depo-Medrol entrapped in the chitosan matrix in order to reach maximal efficiency for drug loading. The optimum concentrations of the chitosan (2.5 g), glutaraldehyde (3.05 µl) and Depo-Medrol (0.1 mg) were set up to achieve the highest value of drug loaded and the most sustained release from the chitosan matrix. In-vitro monitoring of drug release kinetic using high-performance liquid chromatography (HPLC) showed that 73% of the Depo-Medrol released within 120 min, whereas remained drug was released during the next 67 h. High correlation between first order and Higuchi's kinetic models indicates a controlled diffusion of Depo-Medrol through the surrounding media. Moreover, recovery capacity more than 82% and the entrapment efficiency 58-88% were achieved at the optimal conditions. Therefore, the new synthesized Depo Medrol- chitosan is an applicable appliance for arthritis therapy by slow release mechanism. This article is protected by copyright. All rights reserved.
Trauma still stands atop of the list of emergencies. Transfer of these patients via Emergency Med... more Trauma still stands atop of the list of emergencies. Transfer of these patients via Emergency Medical Services (EMS) dispatch is critical with regard to importance of timing. This aspect has achieved greater importance due to population increase and telephone triage. We aimed to decrease unnecessary Emergency Medical Services (EMS) missions via a computer program designed for an algorithmic approach for trauma care by nurses involved in EMS, to help them evaluate the case more accurately. We named our program "Trauma Dispatch Algorithm". First, the most common chief complaints regarding traumatic events were chosen from searching all the calls in December 2008 recorded in Tehran, Iran's EMS center; and then an algorithm approach was written for them. These algorithms were revised by three traumatologists and emergency medicine specialists, after their approval the algorithms were evaluated by EMS dispatch center for their practicality. Finally all data were turned into computer software. The program was used at the Tehran EMS center; 100 recorded calls assessed with each system were selected randomly. They were evaluated by another traumatologist whether it was necessary to send a team to the site or not. The age average was 26 years in both groups. The "trauma dispatch algorithm" was significantly effective in reducing the unnecessary missions of EMS by 16% (from 42% to 26%) (P = 0.005). This program was effective in reducing unnecessary missions. We propose the usage of this system in all EMS centers.
Electrodeposition is known to be proper for separation and preconcentration of extremely low conc... more Electrodeposition is known to be proper for separation and preconcentration of extremely low concentrations of analytes from the bulk sample which is instrumentally very simple. In the present research, a combination of electrodeposition with arc atomic emission spectrometry (ED-AAES) method has been developed in order to improve the analytical performance of this spectrometry technique. The results show that sensitivity and detection limits by using ED-AAES were improved 1000-2000 folds over those of normal arc atomic emission spectrometry in determination of the selected elements. The detection limits for measurement of Ni, Cr and Pb were 2.56, 3.05 and 2.11 µg L − 1 for monodeposition and 3.31, 3.72 and 3.25 µg L − 1 for simultaneously deposition, respectively. The precision of determination was in the range of 2-4% RSD. Typical calibration graphs for these elements were linear up to 100 µg L − 1 , depending on the element and matrix. Application of this technique was also tested on determination of the studied elements in an electroplating plant's waste water. The accuracy of technique was verified by comparing the results of the waste water analysis with those of electrothermal atomic absorption spectroscopy as a reference standard method. The obtained results show that the combined technique (ED-AAES) has been progressed substantially toward the ultimate goal of direct interference-free determination of trace analysis in complex samples by AAES.
ABSTRACT Objective: Children, due to their great parental dependency, are amongst the cases that ... more ABSTRACT Objective: Children, due to their great parental dependency, are amongst the cases that should receive preoperatively medication to reduce their fear and anxiety. The objective of this study was to compare the efficacy of rectal diazepam and midazolam for this purpose in pediatric patients scheduled for elective surgery.Material & Methods: 60 children, aged between 1 and 6 years, scheduled for elective surgery, were included in this double blind, randomized controlled trial. Patients were randomly allocated into three equal groups. Patients in midazolam and diazepam groups received the drugs 0.3 mg/kg and 0.5 mg/kg respectively (in normal saline at a final volume of 2.5 ml) and placebo group received only 2.5 ml of normal saline 20 min before arriving operation room through rectal applicator. Sedation and anxiety scores at the time of separation from their parents before arriving operating room were recorded for all groups.Findings: There was a significant reduction in anxiety level in midazolam and diazepam groups as compared to placebo group (P<0.001). Sedation rate was 65% for midazolam, 60% for diazepam, and 15% for placebo group (P=0.007). There were no significant changes in hemodynamic parameters in the three study groups.Conclusion: With respect to effective anxiolytic and sedative activity, rectal midazolam (0.3 mg/Kg) and diazepam (0.5 mg/Kg) can be used as an anesthetic premedicant for children at pre-operative period and their use is safe regarding hemodynamic variables and related side-effects.
ObjectiveClonidine is an α2-agonist which is used as a sedative premedication in children. There ... more ObjectiveClonidine is an α2-agonist which is used as a sedative premedication in children. There are conflicting results in the published literature about the effect of clonidine on the incidence of post operative nausea and vomiting (PONV). We therefore decided to evaluate the effect of oral clonidine given preoperatively on the incidence of PONV in children after appendectomy.MethodsSixty children, 5-12 years old, classified as American Society of Anesthesiologists physical status I and II, who were scheduled for appendecectomy were enrolled in this randomized double blinded clinical trial. Patients were randomly assigned into two groups of 30 patients. Patients in clonidine group were given 4 µg.kg -1 clonidine in 20 cc of apple juice and patients in control group were given only 20 cc of apple juice 1 hour before transporting to operating room. The protocol of general anesthesia and postoperative analgesia was the same for two groups. Incidence of PONV and antiemetic usage of patients were assessed during 0-24 hours after anesthesia.FindingsThe patients’ characteristics were similar in two groups. Patients who had received clonidine had significantly less episodes of PONV and also less rescue antiemetic usage than patients in control group.ConclusionWe showed that oral clonidine at a dose of 4 µg.kg -1 administered preoperatively is associated with a reduced incidence of postoperative vomiting in children who have undergone appendectomy.
The grain growth kinetics of an extruded fine-grained Mg–9Gd–4Y–0.4Zr (wt%) alloy was investigate... more The grain growth kinetics of an extruded fine-grained Mg–9Gd–4Y–0.4Zr (wt%) alloy was investigated by static annealing in the temperature range of 673–773 K. In addition to the microstructural evolution, textural evolution of the material was also studied during high temperature exposure. The material revealed an unusual basal texture in the extruded condition which was weakened after annealing. The material behavior can be divided into two temperature regimes, namely from 673 to 723 K and from 723 to 773 K. According to the obtained data, although the material shows superior thermal stability in comparison with the conventional Mg alloys, it loses most of its resistance to grain growth at temperatures higher than 673 K. It was observed that although the Mg3(Gd,Y) precipitates have sufficient thermal stability to restrict grain growth, significant grain growth occurs at the highest temperatures where increased mobility of the grain boundaries seems to be dominant. However, there is ...
Case Studies in Engineering Failure Analysis, 2015
ABSTRACT Two packing cups of the second stage cylinders of the polyethylene hyper compressors fai... more ABSTRACT Two packing cups of the second stage cylinders of the polyethylene hyper compressors failed after service life of about three months. In this paper, microstructural investigations and fracture surface studies are presented for failure analysis of the damaged parts. Moreover, the stress analysis is performed by using fatigue striations to evaluate the principal stress components of the lube oil ducts. It is shown that although the design of packing cup elements is very important, the quality of the finished surfaces, wear resistance and mechanical properties of the selected material must be considered to increase the fatigue life of critical parts of the hyper compressor.
Background: Myocarditis is inflammation of the cardiac myocytes. In the first 6 months of life, m... more Background: Myocarditis is inflammation of the cardiac myocytes. In the first 6 months of life, myocarditis is slow-progressing and sudden death is common. It should not be forgotten that these patients can have intrauterine myocarditis. Case Presentation: A 4-month-old male patient had fast breathing and cyanosis during crying in the last month. At admission, we found tachypnea and hypoxia in his physical examination, and cardiomegaly on the chest radiogram. Subsequently, dilatation of left ventricle and left atrium, systolic dysfunction of left ventricle, and mitral valve regurgitation were found in echocardiography. The patient was diagnosed with myocarditis. We were informed that he had a twin brother, so we evaluated the second baby too. Similar but less severe findings were obtained in the echocardiographic examination of the twin brother, who had normal findings in physical examination. Infectious and metabolic scanning tests were performed on both patients. The underlying ca...
Eastern Mediterranean health journal = La revue de santé de la Méditerranée orientale = al-Majallah al-ṣiḥḥīyah li-sharq al-mutawassiṭ
A study in Babol, Islamic Republic of Iran, used a questionnaire to gather information on knowled... more A study in Babol, Islamic Republic of Iran, used a questionnaire to gather information on knowledge about oral cancer and its risk factors and to evaluate the efficacy of an educational brochure. From a community sample of 400 people, 76.0% had no knowledge of oral cancer. Mean knowledge score before the education intervention was 1.47 (standard deviation 3.40) out of 10. Knowledge about oral cancer was not associated with age, sex or education level but urban residents had better knowledge than rural residents. Mean knowledge score improved significantly by 5.92 (SD 3.30) at 1 month after the intervention among the 226 respondents who had read the brochure.
ABSTRACT The microstructure and high-temperature shear strength of the Mg–10Gd–3Y–1.2Zn–0.5Zr all... more ABSTRACT The microstructure and high-temperature shear strength of the Mg–10Gd–3Y–1.2Zn–0.5Zr alloy were investigated in the as-cast and aged (T6) conditions. The shear yield stress (SYS), and ultimate shear strength (USS) were measured by the shear punch test (SPT) in the temperature range of 25–300 �C. The results showed that both USS and SYS of the as-cast alloy are greatly improved after the T6 aging treatment at all test temperatures. However, the variation of strength with temperature showed different trends for the as-cast and aged conditions of the material. The USS of the aged alloy decreased monotonically from 315 MPa at room temperature, to 282 MPa at 300 �C. This was in contrast to the USS values of the as-cast alloy, which first decreased from 270 MPa at room temperature to 255 MPa at 150 �C, and then increased with temperature, passing through maximum values of 263 MPa at 250 �C. The mechanism by which the as-cast and aged alloys show different shear behavior with increasing test temperature was discussed and related to the role of precipitates and the long period stacking ordered (LPSOs) in high temperature strengthening.
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Papers by reza Alizadeh