89 results on '"Mostafa Ahmadi"'
Search Results
2. Multiphysics Sizing of Interior Permanent Magnet Machines Based on Geometric Methodology
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Mostafa Ahmadi Darmani, Andrea Cavagnino, Silvio Vaschetto, Fabrizio Marignetti, and Christopher Gerada
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Air gap flux density ,electromagnetic sizing ,equivalent ring method ,finite element ,interior permanent magnet (IPM) machine ,lumped parameter thermal network ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This study presents a sizing methodology in the frame of the multidisciplinary design of interior permanent magnet synchronous machines. The proposed approach targets at obtaining an initial electromagnetic design of the machine, including diameters, axial length, rotor barrier shape, stator slot geometry as well as the winding layout. The analytical design workflow consists of an iterative sizing procedure based on a robust geometric model, consistent equations, and no correction factors. The process is carried out starting from very basic design parameters such as rated voltage, torque, and magnetic material properties. The modular structure of the proposed design algorithm can be easily integrated with optimization routines obtaining a final optimized design, which contemplates various multiobjective constraints.
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- 2024
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3. Effect of an Escherichia coli–derived phytase and a carbohydrase–protease cocktail derived from Bacillus spp. on performance, digestibility, bone mineralization and gut morphology in broilers fed different nutrient density diets
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Mostafa Ahmadi, Hossein Ali Ghasemi, Iman Hajkhodadadi, and Farhad Khaligh
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bone quality ,broilers ,dietary nutrient ,intestinal health ,multi‐enzyme ,phytase ,Veterinary medicine ,SF600-1100 - Abstract
Abstract Background Enzyme combinations, particularly phytase (PHY) with various carbohydrases and proteases, are utilized in commercial broiler production to enhance nutrient and energy bioavailability. Objective A feeding study was undertaken to determine whether the efficiency of an Escherichia coli–derived PHY and a feed enzyme complex (FEC) derived from Bacillus spp. containing carbohydrase and protease as main activities in broiler chickens is dependent on diet quality. A total of 900 male one‐day‐old broiler chickens (Ross 308) were assigned to a 2 × 3 factorial arrangement of the treatments with 2 different nutrient density diets, standard nutrient diet (SN diet) and a low‐nutrient diet (LN diet; −100 kcal/kg for AMEn and −5% for crude protein [CP] and limiting amino acids), and 3 enzyme treatments (control [no enzymes], PHY and PHY + FEC). Each treatment group was composed of 6 replicates of 25 birds each. Results The LN diet caused a decrease in performance index, tibia length and diameter, tibia calcium content and jejunal villus surface area (VSA). The interaction effects between diet and enzyme supplementation were observed (p
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- 2024
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4. Evaluation of the discrepancy of the bolton ratio in three groups of sagittal skeletal relationships
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Mostafa Ahmadi, Mohammad Chehrazi, and Reza Ghorbanipour
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orthodontics ,malocclusion ,tooth crown ,Dentistry ,RK1-715 - Abstract
Introduction: The outcome of orthodontic treatment depends on the malocclusion and the ratio of the size of the upper and lower teeth. The aim of this study was to evaluate the discrepancy of tooth crown size in different groups of malocclusions. Materials & Methods: In this cross-sectional study, 165 patients referred to the Orthodontic Department of Babol School of Dentistry were randomly selected. The samples were divided into three skeletal malocclusion groups (55 in each group) according to the ANB angle. The level of anterior and total Bolton ratio in the cases was calculated, and the deviation from normal value of anterior and posterior Bolton was calculated. The results were analyzed using the ANOVA and chi-square test. The significance level was set at p
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- 2023
5. Investigation of the association between serum uric acid levels and HEART risk score in patients with acute coronary syndrome
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Ramin Khameneh Bagheri, Mona Najaf Najafi, Mostafa Ahmadi, Mohsen Saberi, Mina Maleki, and Vafa Baradaran Rahimi
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acute coronary syndrome ,HEART score ,uric acid ,Physiology ,QP1-981 - Abstract
Abstract The association between uric acid (UA) and cardio‐metabolic conditions has been recognized for a long time. However, recently, a body of evidence has highlighted the independent role of UA in a series of conditions, including renal and cardiovascular diseases. In this light, data regarding the prognostic role of UA in acute coronary syndrome (ACS) is scarce. A total number of 100 patients, 59 males and 41 females, diagnosed with ACS were recruited in this study. At the time of admission to the hospital, the serum level of UA was measured. In addition, the HEART score was calculated based on each patients' profile. Participants were on average 61.37 ± 12.08 years old. The most prevalent risk factors were hypertension (48%), a history of coronary artery disease (40%), and diabetes mellitus (33%). The average serum level of UA was 5.81 ± 1.81 mg/dl, and the calculated HEART score had a median of six (minimum of two and maximum of ten). A positive yet statistically insignificant correlation was found between the measured UA level and the calculated HEART score (R = 0.375, p = 0.090). However, further studies with larger sample size are required to assess the direct association of UA level with major adverse cardiac events in patients with cardiovascular disease.
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- 2022
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6. An incidental finding of unroofed coronary sinus during angiography confirmed by 3D echocardiography; A case report
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Afsoon Fazlinezhad, Faeze Keihanian, Mostafa Ahmadi, and Mohammad Tayyebi
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atrial septal defect ,cardiac anomaly ,transesophageal echocardiography ,unroofed coronary sinus ,Medicine ,Medicine (General) ,R5-920 - Abstract
Abstract Unroofed coronary sinus (UCS) is an uncommon congenital heart anomaly and the most unusual type of atrial septal defect. This report presents a 71‐year‐old female with palpitation and dyspnea following an emotional stress, who was referred for ablation of typical atrial flutter. Finally diagnosed with a partially unroofed CS causing a bidirectional shunt.
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- 2022
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7. Efficiency Mapping and Weighted Average Efficiency for Large Hydrogenerators
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Edson da Costa Bortoni, Roberto Teixeira Siniscalchi, Silvio Vaschetto, Mostafa Ahmadi Darmani, and Andrea Cavagnino
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Hydrogenerator ,modeling ,efficiency ,testing ,losses ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This paper presents the concept of efficiency mapping for large synchronous hydrogenerators, which are useful for evaluating hydropower generation performance vis-à-vis interconnected intermittent generation to machine efficiency-oriented design. Tests for loss segregation at rated conditions are needed, and models for loss variation along all operational areas are presented. The weighted average efficiency is obtained as the summation of all operating load point efficiencies times related weights, defined according to criteria or from a 2D-histogram of machine operation. The proposed methodology is applied and compared for two machine designs and to an existent machine under operation.
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- 2021
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8. Assessment of the Diagnostic Methods of Mizaj in Persian Medicine: A Systematic Review
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Mostafa Ahmadi, Hoda Shirafkan, and Seyyed Ali Mozaffarpur
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Persian medicine ,temperament ,traditional medicine ,questionnaire ,diagnosis ,Medicine (General) ,R5-920 - Abstract
The concept of mizaj corresponds to the idea of personalized medicine and is the main diagnostic principle of Persian medicine (PM). This study aims to investigate diagnostic tools for the detection of mizaj in PM. In this systematic review of articles published before September 2022, articles were searched for in the Web of Science, PubMed, Scopus, Google Scholar, SID databases, and gray literature. The titles of the articles were screened by researchers and relevant articles were selected. Abstracts were reviewed by two reviewers to select final articles. Subsequently, the articles found were critically evaluated by two reviewers according to the CEBM method. Finally, article data were extracted. Of the 1812 articles found, 54 were included in the final evaluation. Of these, 47 articles were related to the diagnosis of whole body mizaj (WBM). WBM was diagnosed in 37 studies using questionnaires and 10 using expert panels. In addition, six articles examined the mizaj of organs. Only four of these questionnaires were found with reported reliability and validity. There were two questionnaires for assessing WBM, but neither had sufficient reliability and validity. Questionnaires that assess organs had weak designs and lacked sufficient reliability and validity.
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- 2023
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9. Effect of remote ischemic Pre-conditioning on primary percutaneous coronary intervention outcomes: a randomized clinical trial
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Mostafa Dastani, Javad Ramezani, Arash Gholoobi, Mohsen Mouhebati, Ali Eshraghi, Mostafa Ahmadi, and Seyyed Masoud Sajjadi
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ischemic preconditioning ,st-segment elevation myocardial infarction ,percutaneous coronary intervention ,ischemia reperfusion injury ,Medicine (General) ,R5-920 - Abstract
Background: Remote ischemic preconditioning (RIPC) is a simple non-invasive method by using cycles of ischemia and reperfusion on a remote organ. Objective: To determine the effect of RIPC outcomes in patients with ST-segment-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). Methods: This double blind randomized clinical trial was conducted in two teaching and reference hospitals in Mashhad, Iran. Sixty patients with acute STEMI were enrolled from October 2018 to January 2019. The patients were allocated into two groups, by using sealed envelope randomization i.e., a study group of patients who had undergone RIPC intervention and a control group of patients who had not undergone RIPC. Half an hour before PPCI, a sphygmomanometer cuff was placed around the left upper arm and inflated up to 200mmHg for five minutes; then the cuff was deflated for another five minutes, and this cycle was repeated 3 times before or during PPCI. Corrected Thrombolysis in Myocardial Infarction (TIMI) frame count, ST-segment resolution, reperfusion arrhythmias and contrast induced nephropathy (CIN) were evaluated in both groups after PPCI. Study data was analyzed by SPSS version 16. Results: A total number of 26 males and 14 females were studied in study groups (n=20 for each). Both groups were homogenous according to their baseline characteristics. Both TIMI grade and Corrected Thrombolysis in Myocardial Infarction Frame Count CTFC significantly improved after RIPC (p=0.001 and p
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- 2019
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10. Interplay of reversible chain transfer and comonomer incorporation reactions in coordination copolymerization of ethylene/1–hexene
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Ali Ebrahimi, Saeid Ahmadjo, Mohsen Mohammadi, Mohammad-Mahdi Mortazavi, and Mostafa Ahmadi
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coordination polymerization ,reversible chain transfer reaction ,chemical composition ,microstructure ,Polymers and polymer manufacture ,TP1080-1185 - Abstract
Coordinative chain transfer polymerization (CCTP) has opened a new path for the development of novel products like olefin block copolymers and chain-end functional polyolefins. However, conflicting results are frequently reported on the catalyst performance including activity and comonomer selectivity under CCTP conditions. Here we have selected two catalysts including rac-ethylenebis(1-η5-indenyl)zirconocene and bis(imino) pyridine iron, with drastically different comonomer affinities. The effect of diethyl zinc as the chain transfer agent (CTA) on their individual performances is evaluated at different 1–hexene concentrations, in copolymerization with ethylene. Combined thermal fractionation and GPC results confirm that not all chains experience the reversible transfer reaction. Nevertheless, the metallocene catalyst shows twice activity and about 30% lower comonomer incorporation in the presence of CTA. Conversely, the late transition metal catalyst demonstrates lower activity and remains comonomer irresponsive. It could be concluded that, in addition to establishing a reversible transfer reaction, CTA affects the nature of active centers. This finding can help designing olefin copolymers with a more defined chemical composition based on CCTP reaction.
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- 2019
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11. Intracranial Aneurysm Rupture after SARS-CoV2 Infection: Case Report and Review of Literature
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Dilaware Khan, Soheil Naderi, Mostafa Ahmadi, Askar Ghorbani, Jan Frederick Cornelius, Daniel Hänggi, and Sajjad Muhammad
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COVID-19 ,neurosurgery ,neurovascular complications ,aSAH ,Medicine - Abstract
Background: SARS-CoV virus infection results in a dysbalanced and severe inflammatory response with hypercytokinemia and immunodepression. Viral infection triggers systemic inflammation and the virus itself can potentially cause vascular damage, including blood–brain barrier (BBB) disruption and alterations in the coagulation system, which may result in cardiovascular and neurovascular events. Here, we review the literature and present a case of COVID-19 infection leading to an aneurysmal subarachnoid haemorrhage (aSAH). Case Description: A 61-year-old woman presented with dyspnea, cough, and fever. She had a history of hypertension and was overweight with a body mass-index of 34. There was no history of subarachnoid hemorrhage in the family. Due to low oxygen saturation (89%) she was admitted into ICU. A chest CT showed a typical picture of COVID-19 pneumonia. The PCR-based test of an oropharyngeal swab was COVID-19-positive. In addition to oxygen support she was prescribed with favipiravir and hydroxychloroquine. She experienced a sudden headache and lost consciousness on the second day. Computer tomography (CT) with CT-angiography revealed a subarachnoid haemorrhage in the basal cisterns from a ruptured anterior communicating artery aneurysm. The aneurysm was clipped microsurgically through a left-sided standard pterional approach and the patient was admitted again to the intensive care unit for further intensive medical treatment. Post-operatively, the patient showed slight motor dysphasia. No other neurological deficits. Conclusion: Systemic inflammation and ventilator support-associated blood pressure fluctuations may trigger aneurysmal subarachnoid haemorrhage secondary to COVID-19 infection. COVID-19 infection could be considered as one of the possible risk factors leading to instability and rupture of intracranial aneurysm.
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- 2022
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12. Dobutamine stress-induced ischemic right ventricular dysfunction in patients with three-vessel coronary artery disease
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Ramin Khameneh Bagheri, Mostafa Ahmadi, Hedyeh Alimi, Laya Valaee, Toktam Sahranavard, and Mohammad Sobhan Sheikh Andalibi
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Right ventricular dysfunction ,Coronary artery disease ,Dobutamine ,Medicine (General) ,R5-920 - Abstract
Background: Dobutamine stress echocardiography (DSE) is a non-invasive technique to detect coronary artery diseases (CAD). There are limited studies on evaluation of the right ventricular function by stress echocardiography. The appropriate evaluation of RV function and early diagnosis of its failure can help to improve outcomes for the patients undergoing cardiac surgery. Objective: To determine right ventricular dysfunction in patients with three-vessel CAD by using DSE. Methods: This cross-sectional study was among 13 patients who were candidates for coronary artery bypass grafting (CABG) referred to Ghaem Hospital, Mashhad, Iran; from September 2015 to May 2016. After a physical examination and initial measures, DSE was performed and echocardiographic parameters were recorded by a cardiologist. Paired-samples t-test was performed using SPSS Software v.16.0 for data analysis. Results: The study included 13 patients (9 males) with a mean age of 65.4±7.6 years. The mean of TAPS was 16.9±4.5 mm and 15.7±2.9 mm before and after stress echocardiography, respectively (p=0.69). Systolic right ventricular (SRV) peak increased from before DSE compared with after DSE (8.0±2.2 vs. 13.7±4.2 mm/s, p
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- 2018
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13. Data on fluoride contents in groundwater of Bushehr province, Iran
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Sina Dobaradaran, Maryam Khorsand, Abdolreza Hayati, Roya Moradzadeh, Mohammad Pouryousefi, and Mostafa Ahmadi
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Computer applications to medicine. Medical informatics ,R858-859.7 ,Science (General) ,Q1-390 - Abstract
In this article, we measured the levels of fluoride in groundwater. The samples were taken from groundwater in Bushehr's province, Iran. After the collection of samples, the concentration levels of fluoride were determined by the standard SPADNS method using spectrometer. The mean concentration levels of fluoride in water of all stations were higher than the WHO drinking water guideline. Microsoft Office Excel 2016 was used for calculation of mean values. The mean concentration level of fluoride instatement were in the range of 1.52 to 3.64 mg l-1. Keywords: Bushehr, Drinking water, Fluoride, Groundwater, Spectrometer
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- 2018
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14. Septal hematoma due to stent implementation in the septal course of the left anterior descending artery
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Ramin Khameneh-Bagheri, Reza Jafarzadeh-Esfehani, and Mostafa Ahmadi
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Percutaneous Coronary Intervention ,Myocardial Bridge ,Hematoma ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
BACKGROUND: The interventricular septal hematoma (IVSH) is a rare and potentially lethal finding. There are variously reported etiologies including instrumental damages during cardiac interventions. Although there are not enough studies available, conservative management is considered as a preferable approach in stable patients.CASE REPORT: A 45-year man smoker with the previous history of percutaneous coronary intervention (PCI), admitted with unstable angina in present visit. Coronary angiography showed significant in-stent restenosis (ISR) of the left anterior descending (LAD) artery stent. During our intervention for treatment of the ISR, the wire movement caused a diffuse dissection without any runoff, in the distal portion of the LAD. Therefore two stents were deployed in the dissected segment with a short overlapping segment. Unfortunately, the overlapping segment of these stents was located in the myocardial bridge segment. Therefore the contraction of the interventricular septum (IVS) caused a scissor-like movement of the stents, and they ruptured the LAD into the septum. Therefore, the contrast agent was accumulated in the IVS. Immediately, a graft stent was deployed in the overlapping segment of stents and perforation became sealed. In echocardiography, the IVS diameter increased to 30 mm. Since the patient was hemodynamically and electrically stable, he underwent conservative approach and after two months the septum returned to the normal size.CONCLUSION: During PCI on the LAD artery, the implantation of stents in the septal course with a short overlapping segment can result in coronary perforation, and therefore IVS hematoma by the scissor effect. Septal hematoma may cause life-threatening arrhythmias or ventricular septal rupture, but if it is asymptomatic or uncomplicated. Conservative management is the best strategy.
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- 2017
15. A Case Report of Recurrent Rheumatic Fever: Considerations and Comments
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Ramin Khamene Bagheri, Faeze Keihanian, Mostafa Ahmadi, and Samane Hasanzadeh
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infective endocarditis ,prolonged fever ,recurrent rheumatic fever ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 ,Diseases of the respiratory system ,RC705-779 - Abstract
Rheumatic fever (RF) is a prevalent healthcare problem in the developing countries. Recurrence of this disorder is often observed in childhood and adolescence. RF can mimic the presentations of infective endocarditis, and clinicians are not really familiar with this issue. Herein, we present a case of recurrent acute rheumatic fever in a patient suspicious of acute bacterial endocarditis due to her previous RF. Finally, she was definitively diagnosed and underwent valvular replacement surgery and received prophylaxis antibiotics besides regular follow-up
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- 2017
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16. Pulsating mass following plain old balloon angioplasty on left anterior descending artery (LAD) via radial access
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Mostafa Ahmadi, Ramin Khamene-Bagheri, and Reza Jafarzadeh-Esfehani
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Balloon Angioplasty ,Percutaneous Coronary Intervention ,Brachial Artery ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
BACKGROUND: Trans-radial coronary intervention is a popular technique due to patient comfort and lower complication rate. The main complications of this method are artery spasm, vessel perforation, and formation of pseudo-aneurysm.CASE REPORT: In this report, an unusual complication of radial access angiography was encountered. Shortly after the procedure, the patient’s right arm began to swell and a pulsating mass grew over the medial aspect of the arm. Right brachial artery angiography was performed immediately for rolling out brachial artery perforation. There was no evidence of extravasation in brachial angiography. Surprisingly, the mass began to disappear after some active flexion and extension at elbow joint. The same problem occurred again after percutaneous coronary intervention (PCI) on left anterior descending artery (LAD) in this case 2 days later and was resolved by the same maneuver.CONCLUSION: It can be conculded that the brachial artery path was shifted and became entrapped after the procedure due to low soft tissue support.
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- 2018
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17. The Effect of Extended Injection of Subcutaneous Heparin on Pain Intensity and Bruising Incidence
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Mostafa Ahmadi, Raheleh Ahmadi, Zoleykha Saadati, and Omid Mehrpour
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Extended injection time ,Heparin ,Pain intensity ,Medicine (General) ,R5-920 - Abstract
Background: Reducing patients’ pain is one of the main goals of providing clinical services, which requires nursing skill. As a simple technique, increasing the duration of subcutaneous heparin injection may affect the intensity of pain and bruising. Objective: The aim of this study was to assess the effect of increasing the heparin injection time on pain intensity and bruising associated with subcutaneous injection. Methods: The present quasi-experimental study consisted of 86 patients, admitted to our hospital, who were treated with subcutaneous heparin injection. A McGill pain intensity questionnaire was used to measure pain severity in a purposive sampling. All of the subjects received subcutaneous heparin twice for 10 seconds. They also were injected twice with heparin infusion, although it was for 30 seconds this time. The interval between the two injections was 24 h, and the intensity of the pain was measured after each injection. The Pearson correlation coefficient was measured, and analysis of variance (ANOVA) and the t-test were used to analyze the data. Results: Eighty patients received heparin. The body mass indexes were reported as 52 (60%) and 34 (40%) for subjects within the age range of 18.5-24.9 and 25-29.9, respectively. Regarding the mean of pain intensity, there was a significant difference between the 10 and 30 s injections (p ˂ 0.05). Additionally, there was a significant difference in bruising rates between the two methods 48 and 72 h after injection (p ˂ 0.05). The ANOVA test showed a significant association between gender and bruising (p = 0.001). Conclusion: According to the results, by elevating the duration of heparin injection, the severity of pain was reduced, and, therefore, the patients felt more comfortable. Trial Registration: The trial was registered at the Thai Clinical Trials Registry (TCTR) with the TCTR identification of TCTR20160221001. Funding: This research was supported by the research cluster grant (88186-25/01/89) from Mashhad University of Medical Sciences, Mashhad, Iran. The authors received no financial support for the authorship and/or publication of this article.
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- 2016
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18. Evaluation of continuous and discrete melting endotherms in determination of structural heterogeneities in Ziegler-Natta catalyzed linear low density polyethylene
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Mostafa Ahmadi, Seyed Mohammad Mehdi Mortazavi, Saeid Ahmadjo, Majid Zahmati, Khosrow Valieghbal, Davoud Jafarifar, and Reza Rashedi
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chemical composition distribution ,lamella thickness ,short chain branching ,thermal fractionation ,Ziegler-Natta catalyst ,Polymers and polymer manufacture ,TP1080-1185 - Abstract
Ethylene / 1-butene copolymers at different comonomer levels were synthesized using Ziegler-Natta catalyst to evaluate the applicability of thermal fractionation methods in predicting chemical composition distribution (CCD). The continuous melting endotherms by DSC were converted to continuous CCD, and the average comonomer contents were compared with NMR results. DSC underestimated comonomer content specifically at higher levels and was more sensitive to the drawn baseline. The thermally fractionated melting endotherms by SSA method were deconvoluted and transformed into discrete CCDs. SSA method underestimated average comonomer content even more, however results were more reproducible. The main shortcoming of the thermal methods was the inability of short ethylene sequences in forming discernible lamella thicknesses at high comonomer levels. Calibration curves were created for converting the predicted comonomer contents into absolute values and used for studying industrial LLDPEs with different comonomer levels. It was shown that SSA provides more reliable results and correlates more reasonably to the measured densities.
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- 2016
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19. Unusual management of parturient patient with severe bicuspid aortic valve stenosis and congestive heart failure
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Mahdi Kahrom, Mostafa Ahmadi, Behrooz Mottahedi, Masoomeh Tabari, Atieh Vatanchi, Naser Paravi, and Hamid Ghaderi
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Pregnancy ,Aortic stenosis (AS) ,Bicuspid aortic valve (BAV) ,aortic valve replacement (AVR) ,congestive heart failure (CHF) ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
BACKGROUND: Critical aortic stenosis (AS) is an unusual cardiac pathology in pregnancy, but has significant impact on the fetal and maternal outcomes of pregnancy. Pregnant patients with aortic stenosis and heart failure represent a major challenge for the heart team and anesthesiologist who should balance the risks and benefits of different treatment strategies and their effects on the mother and fetus.CASE REPORT: We present a 26-year-old parturient who underwent cesarean section at 30 weeks of gestation under general anesthesia in the presence of cardiac surgical team followed by deferred aortic valve replacement after two weeks.CONCLUSION: This report describes the importance of multidisciplinary preoperative evaluation, and careful surgical and anesthetic planning to avoid the deterioration of perioperative cardiac condition in such patients.
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- 2018
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20. Apical Hypertrophic Cardiomyopathy in a Case with Chest Pain and Family History of Sudden Cardiac Death: A Case Report
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Mostafa Ahmadi and Ramin Khameneh Bagheri
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AHCM ,Family history ,Sudden cardiac death ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 ,Diseases of the respiratory system ,RC705-779 - Abstract
Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, which is caused by a multitude of mutations in genes encoding proteins of the cardiac sarcomere (1). Apical hypertrophic cardiomyopathy (AHCM) is an uncommon type of HCM. The sudden cardiac death is less likely to occur in the patients inflicted with AHCM (2). Herein, we presented the case of a 29-year-old man with AHCM, who had typical exertional chest pain without any cardiovascular risk factors, except for a sudden cardiac death in his older brother at the age of 28 years. After performing complete clinical and paraclinical evaluations, the patient underwent optimal medical treatment with beta-blocker agents without any symptoms.
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- 2017
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21. IN SITU SILICA SUPPORTED METALLOCENE CATALYSTS FOR ETHYLENE POLYMERIZATION
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saeid ahmadjo, hassan arabi, Gholam Zohuri, Gholam Nejabat, Mojtaba Omidvar, Mostafa Ahmadi, and Mohamad Mortazavi
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in situ impregnation ,heterogeneous catalysis ,metallocene ,polyethylene ,silica ,Petroleum refining. Petroleum products ,TP690-692.5 - Abstract
Bis(2-R-ind)ZrCl2 (R: H or phenyl) was supported on different types of silica by in situ impregnation method and used for ethylene polymerization. In this method, the step of catalyst loading on support was eliminated and common alkyl aluminum (triisobutylaluminum, TiBA) cocatalyst was used instead of expensive methyl aluminiumoxane (MAO) cocatalyst in the polymerization. The effect of surface area of silica on the performance of the supported catalysts using three different types of silica including EP12 (390 m2/gr.), PQ3060 (570 m2/gr.) and MCM-41 (1100 m2/gr.) was investigated. The surface area had a more critical role relative to other characteristics of the support in the performance of catalysts. By using MCM-41 as support, the kinetic stability was enhanced. The activity of the supported catalysts was increased by increasing the surface area of silica in the order of MCM-41 > PQ3060 > EP12. The morphology of polymer particles was improved and reactor fouling was eliminated by supporting the catalyst.
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- 2014
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22. Three Different Imaging Modalities of a Patient with the Aortic Coarctation
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Ramin Khameneh Bagheri, Leila Bigdelu, and Mostafa Ahmadi
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Double Valve Replacement ,Rheumatic Heart Disease ,Starr Edwards Valve ,St. Jude Valve ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 ,Diseases of the respiratory system ,RC705-779 - Abstract
The patient was a 19 year-old woman with the diagnosis of resistant hypertension, although she was under treatment of three classes of anti-hypertensive drugs (beta blocker, angiotensin receptor blocker, diuretic) for more than one year. In physical examination there was only a significant difference between the systolic blood pressure of upper and lower extremities (200 vs. 120 mmHg), without any other remarkable finding. Three different imaging modalities (echocardiography (Figure 1), CT angiography (Figure 2), conventional aortography (Figure 3) confirmed the aortic coarctation at 30 mm after left subclavian artery origin, with the 3.5-4 mm diameter of the narrowest segment. She underwent implantation of a self-expanding aortic stent and therefore the systolic pressure gradient decreased from 90 to 15 mmHg. After three months, her blood pressure was stable on 110/80 mmHg, while she received only metoprolol 25 mg twice daily and follow-up echocardiography showed 15-20 mmHg pressure gradient through the stent.
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- 2017
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23. The Effect of the Type of Hemodialysis Buffer on the QTc Interval in Patients on Chronic Hemodialysis
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Reza Hekmat, Abddollah Bahrami, Mostafa Ahmadi, and Hossein Nazari
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Chronic ,hemodialysis ,dialysate buffer ,Medicine (General) ,R5-920 - Abstract
Background: Identifying the sources of variation in QTc measurementsis important for preventing arrhythmias during and afterhemodialysis. The present study was designed to determine thecorrelation between the type of hemodialysis buffer and thechanges in QTc interval in patients on chronic hemodialysis.Methods: Fifty-nine patients on chronic hemodialysis whoreferred in winter 2007 to hemodialysis centers of Ghaem andHashemi Nejad hospitals, in Mashhad, Iran, were divided intotwo groups according to their last dialysate buffer: acetate orbicarbonate. Electrocardiography, arterial blood gas parameters,serum K+, Na+, ionized calcium, and albumin levels weremeasured prior to and after hemodialysis in all patients.Results: All arterial blood gas parameters and serum electrolytesconcentrations were increased except K+ levels that weresignificantly decreased with hemodialysis. PCO2 and QTc intervalswere slightly increased in all patients, however thisincrease was not statistically significant. We found that thetype of dialysate affected the QTc interval, HCO3, base excess,base excess of extra cellular fluid, and base bufferchanges with no effect on ionized calcium, pH, PCO2, andserum albumin concentration. QTc interval was prolonged byusing bicarbonate and shortened by using acetate dialysatebuffer. We found no correlation between the variations of QTcinterval and serum electrolytes or arterial blood gas parametersin either group.Conclusion: Bicarbonate buffer use in hemodialysis prolongedQTc interval and acetate buffer shortened it. This effectis independent of serum electrolytes and pH changes duringhemodialysis. The effect of bicarbonate buffer is probablydue to more tolerability of ultra filtration, more effectiveedema reduction and augmented body electro-conductivity.
- Published
- 2009
24. Clinical outcome, and survival between primary percutaneous coronary intervention versus fibrinolysis in patients older than 60 years with acute myocardial infarction
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H Falsoleiman, G H Fatehi, M Dehghani, M T Shakeri, Baktash Bayani, Mostafa Ahmadi, and Atoosheh Rohani
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Acute myocardial infarction ,fibrinolysis ,primary percutaneous coronary intervention ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Objective: The aim of the present study was to compare the short-term and 6-month clinical outcome, and survival in patients older than 60 years with ST-elevation myocardial infarction randomized to either primary percutaneous coronary intervention (PPCI) or thrombolysis. Materials and Methods: 82 patients with STEMI older than 60 years were randomized to either primary PCI or thrombolysis from September 2006 to August 2008. Angiograms were reviewed by two interventionalists not involved in the study. Patients randomized to primary PCI received Aspirin and 600 mg Clopidogrel. Heparin was administered in conjunction with PCI. Patients randomized to thrombolysis received Aspirin followed by streptokinase infusion for one hour. Rescue PCI was considered if there was ongoing pain and ST-segment resolution was
- Published
- 2012
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25. Connectivity Defects in Metallo-Supramolecular Polymer Networks at Different Self-Sorting Regimes
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Mostafa Ahmadi, Lucas Löser, Gerard Pareras, Albert Poater, Kay Saalwächter, and Sebastian Seiffert
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General Chemical Engineering ,Materials Chemistry ,General Chemistry - Published
- 2023
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26. Investigation of the Influence of Tunneling on Bridge Foundation in Urban Area
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Mostafa Ahmadi, Ali Torkashvand, Amirhossein Badraddini, Vahab Sarfarazi, and Shirin Jahanmiri
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Architecture ,Soil Science ,Geology ,Geotechnical Engineering and Engineering Geology - Published
- 2023
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27. Increasing cardiac troponin-I level as a cardiac injury index correlates with in-hospital mortality and biofactors in severe hospitalised COVID-19 patients
- Author
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Reza Javidi Dasht Bayaz, Vahid Reza Askari, Mohammad Tayyebi, Mostafa Ahmadi, Alireza Heidari-Bakavoli, and Vafa Baradaran Rahimi
- Subjects
Microbiology (medical) ,Infectious Diseases ,Pharmacology (medical) - Abstract
Severe acute respiratory syndrome coronavirus-2 raised in 2019 (COVID-19) affects the lung tissue and other organs, specifically the heart.The current study evaluated 120 hospitalised patients with severe COVID-19 between March 2021 and February 2022. Patients' demographics, vital signs, electrocardiogram abnormalities, clinical laboratory tests, including troponin I (TPI), mortality, and discharge type, were recorded.Among the 120 hospitalised patients with severe COVID-19, 54 (45.0%) patients were male, with an average age of 63.2 ± 1.4. Many patients have chronic comorbidities, including hypertension (51.6%), diabetes mellitus (34.1%), and ischemic heart disease (17.5%). The in-hospital and six months after the discharge mortality were 45.8% and 21.5%, respectively. Cardiac injury was observed in 14 (11.7%) patients with a mean TPI level of 8.386 ± 17.89 μg/L, and patients with cardiac injury had higher mortality than those without cardiac injury (P 0.001). Furthermore, the cardiac injury was meaningfully correlated with age (ρ = 0.182, P = 0.019), history of ischemic heart disease (ρ = 0.176, P = 0.05), hospitalisation result and mortality (ρ = 0.261, P = 0.004), inpatient in ICU (ρ = 0.219, P = 0.016), and serum levels of urea (ρ = 0.244, P = 0.008) and creatinine (ρ = 0.197, P = 0.033). Additionally, the discharge results were significantly correlated with oxygen saturation with (ρ = -0.23, P = 0.02) and without (ρ = -0.3, P = 0.001) oxygen therapy, D-dimer (ρ = 0.328, P = 0.019), LDH (ρ = 0.308, P = 0.003), urea (ρ = 0.2, P = 0.03), and creatinine (ρ = 0.17, P = 0.06) levels.Elevated TPI levels are associated with increased mortality in severe COVID-19 patients. Therefore, TPI may be a beneficial biofactor for early diagnosis of cardiac injury and preventing a high mortality rate.
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- 2023
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28. Self-Sorting of Transient Polymer Networks by the Selective Formation of Heteroleptic Metal–Ligand Complexes
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Albert Poater, Mostafa Ahmadi, and Sebastian Seiffert
- Subjects
Inorganic Chemistry ,Polymers and Plastics ,Organic Chemistry ,Materials Chemistry - Published
- 2023
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29. Network Percolation in Transient Polymer Networks with Temporal Hierarchy of Energy Dissipation
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Mostafa Ahmadi, Paola Nicolella, and Sebastian Seiffert
- Subjects
Inorganic Chemistry ,Polymers and Plastics ,Organic Chemistry ,Materials Chemistry - Published
- 2022
- Full Text
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30. Comparison of 660-nm low-level and defocused 810-nm high-power laser for treatment of herpes labialis
- Author
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Mostafa Ahmadi, Amir Mansour Shirani, Shirin Zahra Farhad, Maryam Khosravi, and Maziar Mir
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Periodontics ,Dentistry (miscellaneous) ,Orthodontics ,Oral Surgery - Published
- 2022
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31. Backbone Polarity Tunes Sticker Clustering in Hydrogen-Bonded Supramolecular Polymer Networks
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Mostafa Ahmadi, Amir Jangizehi, and Sebastian Seiffert
- Subjects
Inorganic Chemistry ,Polymers and Plastics ,Organic Chemistry ,Materials Chemistry - Published
- 2022
- Full Text
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32. Defect-controlled softness, diffusive permeability, and mesh-topology of metallo-supramolecular hydrogels
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Paola Nicolella, Martha Franziska Koziol, Lucas Löser, Kay Saalwächter, Mostafa Ahmadi, and Sebastian Seiffert
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technology, industry, and agriculture ,macromolecular substances ,General Chemistry ,Condensed Matter Physics - Abstract
Hydrogels are polymer networks swollen in water; they are suitable materials for biomedical applications such as tissue engineering and drug delivery. In the latter, the controlled diffusion of small diffusants inside the network is essential, as it determines the release mechanism of the drug. In general, the diffusion inside a polymer network is controlled by its mesh-size. Here, we actively control the diffusivity and also the softness of metallo-supramolecular hydrogels
- Published
- 2022
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33. Colchicine effectively attenuates inflammatory biomarker high-sensitivity C-reactive protein (hs-CRP) in patients with non-ST-segment elevation myocardial infarction: a randomised, double-blind, placebo-controlled clinical trial
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Mostafa Ahmadi, Hossein Naghedinia, Vafa Baradaran Rahimi, Vida Vakili, Vahid Reza Askari, and Arash Gholoobi
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Adult ,Male ,medicine.medical_specialty ,Immunology ,Anti-Inflammatory Agents ,Placebo ,Gastroenterology ,chemistry.chemical_compound ,Pericarditis ,Double-Blind Method ,Internal medicine ,medicine ,Humans ,Colchicine ,Pharmacology (medical) ,Myocardial infarction ,Non-ST Elevated Myocardial Infarction ,Aged ,Inflammation ,Pharmacology ,Ejection fraction ,biology ,business.industry ,C-reactive protein ,Middle Aged ,medicine.disease ,Gout ,Clinical trial ,C-Reactive Protein ,chemistry ,Disease Progression ,biology.protein ,Female ,business ,Biomarkers ,Follow-Up Studies - Abstract
Myocardial infarction without ST-segment elevation (NSTEMI) is considered an inflammatory disorder associated with a high mortality rate worldwide. High-sensitivity C-reactive protein (hs-CRP) is an important inflammatory marker for NSTEMI and related to cardiovascular events. Colchicine, as a potent anti-inflammatory drug, is frequently prescribed for the treatment of gout and pericarditis. The present study aimed to evaluate the effects of colchicine, as an anti-inflammatory drug, on hs-CRP levels in NSTEMI patients. We performed a randomised, double-blind, placebo-controlled trial involving 150 NSTEMI patients referred to Imam Reza and Ghaem Hospitals affiliated to Mashhad University of Medical Sciences. The patients were randomised to receive colchicine or placebo along with optimal medications for 30 days. The hs-CRP was measured at the admission and end of the study. Our results revealed that, in both colchicine and placebo groups, hs-CRP levels were significantly mitigated in NSTEMI patients compared to baseline (P
- Published
- 2021
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34. Promoting the electrical conductivity of polyimide/in-situ reduced graphene oxide nanocomposites by controlling sheet size
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Leila Sadat Rokni Hosseini, Ali Mohammad Bazargan, Farhad Sharif, and Mostafa Ahmadi
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General Chemical Engineering ,Organic Chemistry ,Materials Chemistry ,Surfaces, Coatings and Films - Published
- 2023
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35. Tandem coordinative chain transfer polymerization for long chain branched Polyethylene: The role of chain displacement
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Arezoo Dashti, Mostafa Ahmadi, Vahid Haddadi-Asl, Saeid Ahmadjo, and Seyed Mohammad Mahdi Mortazavi
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Polymers and Plastics ,Organic Chemistry ,Materials Chemistry ,General Physics and Astronomy - Published
- 2023
- Full Text
- View/download PDF
36. Coordination Geometry Preference Regulates the Structure and Dynamics of Metallo-Supramolecular Polymer Networks
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Sebastian Seiffert and Mostafa Ahmadi
- Subjects
chemistry.chemical_classification ,Quantitative Biology::Biomolecules ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Structure (category theory) ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Preference ,0104 chemical sciences ,Quantitative Biology::Subcellular Processes ,Inorganic Chemistry ,Supramolecular polymers ,chemistry ,Chemical physics ,Materials Chemistry ,0210 nano-technology ,Coordination geometry - Abstract
Metal–ligand interactions are extensively used for the development of biomimetic polymers. Macroscopic properties of such systems are closely tied to the microscopic structure and dynamics of not o...
- Published
- 2021
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37. Bio-inspired surface modification of iron oxide nanoparticles for active stabilization in hydrogels
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Donya Monji, Faramarz Afshar Taromi, and Mostafa Ahmadi
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chemistry.chemical_classification ,Vinyl alcohol ,Materials science ,Composite number ,Nanoparticle ,02 engineering and technology ,General Chemistry ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Colloid ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Self-healing hydrogels ,Surface modification ,0210 nano-technology ,Iron oxide nanoparticles - Abstract
Biological materials employ a variety of dynamic interactions in sophisticated composite structures to function adaptively on different time and length scales. Inspired by such designs we develop a novel surface modification approach to promote dynamic interactions between nanoparticles and polymer chains in physical and double network hydrogels. Physical hydrogels are formed via reversible complexation of borate ions with poly(vinyl alcohol) (PVA) and chemical crosslinks are introduced by electron beam irradiation. Dopamine is used for surface modification of magnetic iron oxide nanoparticles (MNPs) in two different ways: the direct treatment results in anchoring via catechol groups, whereas the indirect method leaves the catechol group on the free surface of MNPs. Although the former particles show very good colloidal stability, they lower the network connectivity, which results in lower plateau modulus, faster terminal relaxation, and lower yield stress, presumably due to imposing an extra distance between PVA chains. In contrast to this passive design, the latter particles actively reinforce the network by forming clusters of physical bonds between catechol groups of the individual particles and the monodiol complexes of the borate ions and PVA chains. Moreover, the additional complexes formed upon the introduction of nanoparticles with active surfaces provide further energy dissipation potential and therefore enhance the toughness. This approach can help develop novel hydrogels with superior toughness and multiple stimuli-responsiveness.
- Published
- 2021
- Full Text
- View/download PDF
38. Assessing growth parameters of children with congenital hypothyroidism subject to levothyroxine treatment compared to normal growth parameters in healthy newborns
- Author
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Mostafa Ahmadi Milasi, Mohammad Reza Malek Ahmadi, Abolfazl Khoshdel, Gholamreza Panahandeh, and Forouzan Ganji
- Subjects
Pediatrics ,medicine.medical_specialty ,Percentile ,Newborn screening ,business.industry ,Levothyroxine ,Retrospective cohort study ,medicine.disease ,Congenital hypothyroidism ,03 medical and health sciences ,0302 clinical medicine ,030225 pediatrics ,Inclusion and exclusion criteria ,medicine ,Normal growth ,030212 general & internal medicine ,business ,Body mass index ,medicine.drug - Abstract
Background and aims: Congenital hypothyroidism (CH) is one of the most common treatable physical growth disorders leading to mental retardation. Most cases of this disease can be detected through the neonatal screening program. Given the high prevalence of this disease and the implementation of screening programs in recent years in Iran, this study aimed to assess the growth indices of newborns with CH. Methods: In this retrospective cohort study, 66 newborns with CH detected in the screening program in Shahrekord were selected by a census sampling method. Overall, 125 healthy newborns were also selected as controls by the convenience sampling technique according to the inclusion and exclusion criteria. The height, weight, head circumference, and body mass index (BMI) of the samples were measured and then the mean, median, standard deviation, as well as the 3rd, 15th, 25th, 50th, 75th, 85th, and 97th percentiles in the two groups were determined and compared based on gender and age group. Results: The height, weight, head circumference, and BMI of the boys, in addition to the head circumference and BMI of the girls, were not significantly different from those of the controls (P>0.05). However, the height and weight of the girls were significantly lower compared to those in the control group, although the difference in the weight was corrected at the age of 9 months. Conclusion: In general, the growth indices of newborns with CH were lower than those of the controls. This difference was significant only for the weight and height of girls with CH.
- Published
- 2020
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39. Coordination geometry in metallo-supramolecular polymer networks
- Author
-
Batoul Hosseinzadeh and Mostafa Ahmadi
- Subjects
Inorganic Chemistry ,History ,Polymers and Plastics ,Materials Chemistry ,Business and International Management ,Physical and Theoretical Chemistry ,Industrial and Manufacturing Engineering - Published
- 2022
- Full Text
- View/download PDF
40. Investigation of the minimum detectable activity of radioxenon isotopes using an active guard
- Author
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Mostafa Ahmadi
- Subjects
Guard (information security) ,Isotope ,Health, Toxicology and Mutagenesis ,Radiochemistry ,Public Health, Environmental and Occupational Health ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Pollution ,0104 chemical sciences ,Analytical Chemistry ,Activity measurements ,Nuclear Energy and Engineering ,Phoswich detector ,Environmental science ,Environmental isotopes ,Radiology, Nuclear Medicine and imaging ,Gamma spectroscopy ,Spectroscopy - Abstract
One of the current challenges of the Comprehensive Nuclear-Test-Ban Treaty Organization, is reducing the minimum detectable activity and increasing the precision of the detection of radioactive noble gases; namely 135Xe, 133Xe, 133mXe, and 131mXe. These gases are typically detected by systems that use beta-gamma coincidence spectroscopy and gamma spectroscopy for activity measurement. In all of them, a lead shield (passive guard) is used to reduce the environmental isotopes. In this work, the concept of the active guard used in LSC systems has been improved upon for gaseous radioactive samples in a phoswich detector through Geant4 simulations. The simulation results showed that the use of an active guard results in a reduction in the minimum detectable activity, compared to those without an active guard.
- Published
- 2019
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- View/download PDF
41. Effect of remote ischemic Pre-conditioning on primary percutaneous coronary intervention outcomes: a randomized clinical trial
- Author
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Mohsen Mouhebati, Mostafa Dastani, Ali Eshraghi, Arash Gholoobi, Seyyed Masoud Sajjadi, Mostafa Ahmadi, and Javad Ramezani
- Subjects
ischemia reperfusion injury ,medicine.medical_specialty ,lcsh:R5-920 ,business.industry ,medicine.medical_treatment ,percutaneous coronary intervention ,Percutaneous coronary intervention ,law.invention ,Randomized controlled trial ,ischemic preconditioning ,law ,Pre conditioning ,Emergency medicine ,Medicine ,cardiovascular diseases ,business ,st-segment elevation myocardial infarction ,lcsh:Medicine (General) - Abstract
Background: Remote ischemic preconditioning (RIPC) is a simple non-invasive method by using cycles of ischemia and reperfusion on a remote organ. Objective: To determine the effect of RIPC outcomes in patients with ST-segment-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). Methods: This double blind randomized clinical trial was conducted in two teaching and reference hospitals in Mashhad, Iran. Sixty patients with acute STEMI were enrolled from October 2018 to January 2019. The patients were allocated into two groups, by using sealed envelope randomization i.e., a study group of patients who had undergone RIPC intervention and a control group of patients who had not undergone RIPC. Half an hour before PPCI, a sphygmomanometer cuff was placed around the left upper arm and inflated up to 200mmHg for five minutes; then the cuff was deflated for another five minutes, and this cycle was repeated 3 times before or during PPCI. Corrected Thrombolysis in Myocardial Infarction (TIMI) frame count, ST-segment resolution, reperfusion arrhythmias and contrast induced nephropathy (CIN) were evaluated in both groups after PPCI. Study data was analyzed by SPSS version 16. Results: A total number of 26 males and 14 females were studied in study groups (n=20 for each). Both groups were homogenous according to their baseline characteristics. Both TIMI grade and Corrected Thrombolysis in Myocardial Infarction Frame Count CTFC significantly improved after RIPC (p=0.001 and p
- Published
- 2019
42. Rheological modifiers based on supramolecular block copolymers: From weak associations to interconnected micelles
- Author
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Mostafa Ahmadi, Seyed Reza Ghaffarian, Evelyne Van Ruymbeke, Amir Jangizehi, Bart Goderis, Hadi Goldansaz, Olivier Verkinderen, and Goolia Nikravan
- Subjects
Acrylate ,Materials science ,Polymers and Plastics ,Small-angle X-ray scattering ,Hydrogen bond ,General Chemical Engineering ,Relaxation (NMR) ,Supramolecular chemistry ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Micelle ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Rheology ,Materials Chemistry ,Copolymer ,Environmental Chemistry ,0210 nano-technology - Abstract
The rheological spectra of poly(n-butyl acrylate) in the presence of a series of P(nBA-b-HEMA) rheology modifiers show a two-step relaxation process originating from the PnBA matrix and the self-assemblies. The HEMA segments are further grafted with strong, hydrogen bonding UPy groups, which both magnifies and slows down the relaxation of the assemblies. The extents of associations are enlightened by studying thermal transitions in DSC, morphological developments by SAXS, and description of rheological properties using a tube-based model. It is revealed that a weak association tendency, due to long hydrophobic blocks, leads to the formation of double-linear or star assemblies, while increasing the association strength results in the formation of micelles. In an optimum block length and UPy content, loosely entangled diblock additives can form an interconnected micellar network with significantly long relaxation time.
- Published
- 2019
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43. Effect of different chain transfer agents in the coordinative chain transfer oligomerization of dec-1-ene
- Author
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Ahad Hanifpour, Mostafa Ahmadi, Mehdi Nekoomanesh-Haghighi, and Naeimeh Bahri-Laleh
- Subjects
Inorganic Chemistry ,Organic Chemistry ,Spectroscopy ,Analytical Chemistry - Published
- 2022
- Full Text
- View/download PDF
44. Reversible Hydrogels with Switchable Diffusive Permeability
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Paola Nicolella, Daniel Lauxen, Sebastian Seiffert, and Mostafa Ahmadi
- Subjects
540 Chemistry and allied sciences ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Diffusive permeability ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Chemical engineering ,540 Chemie ,Self-healing hydrogels ,Polymer chemistry ,Materials Chemistry ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Hydrogels are polymer networks swollen in water that are characterized by soft mechanics and high permeability. This makes them good candidates for separation and membrane technologies. The diffusion is controlled by the mesh size of the network, and this can be made tunable through the introduction of thermoresponsive polymers. However, this is still a developing field. To contribute to this development, a dual dynamic network is formed composed of four-arm polyethylene glycol precursors in which each arm is functionalized with both a terpyridine moiety capable of forming reversible metal–ligand complexes along with branches of poly(N-isopropylacrylamide) (pNIPAAm), which can be switched between expanded and collapsed states and therewith offers a path for switching the microscopic gel-network mesh size, along with the macroscopic gel elasticity. The dually sensitive hydrogel has the capability of doubling its elastic modulus when going above the lower critical solution temperature (LCST) of pNIPAAm. In addition, the diffusive permeability of the hydrogel is switched upon change of temperature, whereby diffusants are trapped above the LCST of pNIPAAm. Moreover, it is possible to disassemble and reform the gel upon change of pH. With that, the hydrogel has potential application as a switchable and reversible membrane.
- Published
- 2021
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45. Dynamics of supramolecular associative polymer networks at the interplay of chain entanglement, transient chain association, and chain‐sticker clustering
- Author
-
Sebastian Seiffert, Mostafa Ahmadi, and Amir Jangizehi
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Supramolecular chemistry ,02 engineering and technology ,Quantum entanglement ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Turn (biochemistry) ,Chain (algebraic topology) ,chemistry ,Chemical physics ,Materials Chemistry ,Cluster (physics) ,Physical and Theoretical Chemistry ,0210 nano-technology ,Cluster analysis ,Associative property - Abstract
The dynamic mechanical properties of supramolecular associative polymer networks depend on the average number of entanglements along the network‐forming chains, Nₑ, and on their content of associative groups, f. In addition, there may be further influence by aggregation of the associative groups into clusters, which, in turn, is influenced by the chemical structure of these groups, and again by Nₑ and f of the polymer. Therefore, the effects of these parameters are interdependent. To conceptually understand this interdependency, we study model networks in which (a) Nₑ, (b) f, and (c) the chemical structure of the associative groups are varied systematically. Each network is probed by rheology. The clustering of the associative groups is assessed by analyzing the rheological data at the end range of frequency covered and by comparison of the number of supramolecular network junctions with the maximum possible number of binary transient bonds. We find that if the total number of the network junctions, which can be formed either by interchain entanglement or by interchain transient associations, is greater than a threshold of 13, then the likelihood of cluster formation is high and the dynamics of supramolecular associative polymer networks is mainly controlled by this phenomenon. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1209–1223
- Published
- 2019
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46. Preparation of well-defined Poly(Vinyl alcohol) by hydrolysis of Poly(Vinyl acetate) synthesized by RAFT suspension polymerization
- Author
-
Hamid Reza Hedayati, Manouchehr Khorasani, Mostafa Ahmadi, and Nicholas Ballard
- Subjects
Polymers and Plastics ,Organic Chemistry ,Materials Chemistry - Published
- 2022
- Full Text
- View/download PDF
47. Amphiphilic olefin block copolymers synthesized by successive coordinative chain transfer and ring-opening polymerizations
- Author
-
Farhad Jamali, Davood Hassanian-Moghaddam, Saeid Ahmadjo, Seyed Mohammad Mahdi Mortazavi, Yasaman Maddah, and Mostafa Ahmadi
- Subjects
Polymers and Plastics ,Organic Chemistry ,Materials Chemistry ,General Physics and Astronomy - Published
- 2022
- Full Text
- View/download PDF
48. Successful treatment of prosthetic pulmonary valve thrombosis with reteplase: a case report
- Author
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Ramin Khameneh Bagheri, Mostafa Ahmadi, Faeze Keihanian, and Mohammad Ali Ansari
- Subjects
medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Reteplase ,General Medicine ,Thrombolysis ,030204 cardiovascular system & hematology ,medicine.disease ,Thrombosis ,Prosthesis ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Pulmonary valve ,medicine ,030212 general & internal medicine ,Prosthetic Valve Thrombosis ,Complication ,business ,medicine.drug ,Tetralogy of Fallot - Abstract
Pulmonary prosthetic valve thrombosis is a serious and rare complication with high mortality. Using reteplase for treatment of prosthesis thrombosis is rarely reported. We report the first case in Iran of a thrombosed pulmonary valve in a patient who had undergone repair of tetralogy of Fallot, which was successfully treated twice with intravenous thrombolytic therapy with reteplase.
- Published
- 2018
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49. Synthesis and Characterization of Isotactic Poly(1-hexene)/Branched Polyethylene Multiblock Copolymer via Chain Shuttling Polymerization Technique
- Author
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Mostafa Ahmadi, Seyed Mohammad Mahdi Mortazavi, Saeid Ahmadjo, Ahmad Soleimannezhad, and Mohammad Hossein Jandaghian
- Subjects
Materials science ,General Chemical Engineering ,02 engineering and technology ,General Chemistry ,Polyethylene ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Chain shuttling polymerization ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,Monomer ,chemistry ,Polymerization ,Chain walking ,Tacticity ,Polymer chemistry ,Copolymer ,Molar mass distribution ,0210 nano-technology - Abstract
Understanding from the underlying mechanism of chain shuttling polymerization (CSP) is limited due to scarceness of successful reports and incompetence of traditional characterization techniques to distinguish blocky structures. Here, a simple synthesis approach for production of an isotactic poly(1-hexene)/branched polyethylene multiblock copolymer from a 1-hexene monomer is presented. Resulting copolymers can be easily characterized because of their solubility in most organic solvents. This novel blocky architecture is synthesized using ansa-ethylenebis(1-η5-indenyl)zirconium dichloride and α-diimine nickel(II) bromide catalysts. While the former participates in 1,2-enchainment of monomers and produces amorphous segments, the latter forms methylene sequences through chain walking reaction. A quasi-living polymerization is established by reversible transfer of growing chains between catalyst components, as manifested by narrowing molecular weight distribution. 13C NMR analysis confirms that the blocky st...
- Published
- 2018
- Full Text
- View/download PDF
50. Dynamics of entangled supramolecular polymer networks in presence of high-order associations of strong hydrogen bonding groups
- Author
-
Seyed Reza Ghaffarian, Mostafa Ahmadi, and Amir Jangizehi
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Hydrogen bond ,Relaxation (NMR) ,Supramolecular chemistry ,Stacking ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Dissociation (chemistry) ,0104 chemical sciences ,Supramolecular polymers ,chemistry ,Chemical physics ,Polymer chemistry ,High order ,0210 nano-technology - Abstract
Dynamics of entangled polymer chains in the melt state are deliberately excluded in most of the studies on supramolecular polymer networks by utilizing nonentangled precursor chains. Relaxation of the system mainly depends on the dissociation of the associative groups in latter case and nonentangled chains deliver nothing to resist afterward. Conversely, in an entangled system, relaxation of polymer chains and dissociation of associative groups can occurred parallel. Supramolecular networks based on an entangled precursor polymer with different levels of strong associating ureidopyrimidinone (UPy) groups are synthesized to screen the corresponding effects on the dynamics of the system. Binary-associated UPy groups phase separate into collective assemblies by stacking and form high-order, needle-like domains at higher UPy contents. Relaxation of polymer chains is significantly hindered due to the trapping of polymer segments between UPy stacks. Above a certain threshold of UPy content (~4 mol%), the plateau level and final relaxation time of networks show a significant jump, which is attributed to the onset of high-order association of UPy groups.
- Published
- 2017
- Full Text
- View/download PDF
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