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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Transactions on Combinatorics
- نوع مقاله: Journal Article
- کلمات کلیدی: Transitive group,Derangements,Polycirculant Conjecture
- چکیده:
- چکیده انگلیسی: Fixed-point-free permutations, also known as derangements, have been studied for centuries. In particular, depending on their applications, derangements of prime-power order and of prime order have always played a crucial role in a variety of different branches of mathematics: from number theory to algebraic graph theory. Substantial progress has been made on the study of derangements, many long-standing open problems have been solved, and many new research problems have arisen. The results obtained and the methods developed in this area have also effectively been used to solve other problems regarding finite vertex-transitive graphs. The methods used in this area range from deep group theory, including the classification of the finite simple groups, to combinatorial techniques. This article is devoted to surveying results, open problems and methods in this area.
- انتشار مقاله: 03-06-1397
- نویسندگان: Majid Arezoomand,Alireza Abdollahi,Pablo Spiga
- مشاهده
- جایگاه : پژوهشی
- مجله: Reviews in Clinical Medicine
- نوع مقاله: Journal Article
- کلمات کلیدی: Body Mass Index,Ventricular function,Roux-en-Y gastric bypass
- چکیده:
- چکیده انگلیسی: Introduction: Weight gain and obesity are two important public health problems, which are associated with many diseases such as cardiovascular disorders. Various policies such as bariatric surgery have been proposed for the treatment of morbid obesity.
Methods: PubMed and Scopus were searched thoroughly with the following search terms (roux-en-y gastric bypass surgery) AND (ventricular function, OR cardiac risk factors OR heart)) AND (BMI OR body mass index) to find the articles in which the effect of roux-en-Y gastric bypass (RYGB) surgery had been evaluated in severely obese patients.
Result: Out of 120 articles which were found in PubMed, and 28 records which were found in Scopus, only 18 articles fully met the inclusion criteria. Out of 2740 participants in the included studied, 1706 were patients with body mass index (BMI) over 40 kg/m2 who had undergone RYGB surgery, and 1034 were control participants. Results of the studies showed that RYGB surgery could reduce BMI, and cardiac risk factors, and improve diastolic function, systolic and diastolic blood pressures, and aortic function, postoperatively.
Discussion: Obesity is associated with increased risk of cardiovascular diseases, impaired cardiac function, and hypertension. It is shown that RYGB surgery reduces the serum level of biochemical markers of cardiac diseases. Cardiac structure, parasympathetic indices of autonomic function, coronary circulatory function, hypertension, epicardial fat thickness, and ventricular performance improve after bariatric surgery.
Conclusions: It is concluded that RYGB surgery is an effective strategy to improve ventricular function and cardiac risk factors in morbid obese patients.- انتشار مقاله: 19-12-1393
- نویسندگان: Alireza Abdollahi Moghaddam,Ali Jangjoo,Fereshteh Ghaderi,Majid Erfanzadeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Reviews in Clinical Medicine
- نوع مقاله: Journal Article
- کلمات کلیدی: Renovascular hypertension,Atherosclrotic renal artery stenosis,Ischemic nephropathy,Renal artery angioplasty
- چکیده:
- چکیده انگلیسی: Ischemic nephropathy is defined as a clinically significant progressive reduction in glomerular filtration rate that is usually associated with significant renal artery stenosis (unilateral or bilateral involvement). Atherosclerotic renal artery disease is known as the most common cause of the ischemic nephropathy. These patients may develop secondary hypertension. In addition, epidemiologic data has showed a clear association between atherosclerotic renal artery stenosis and coronary artery disease and other cardiovascular disease. Despite the preserving function of kidney on various autoregulation processes, unusual microvascular function will be resulted due to sustained decline in renal perfusion. The ischemic nephropathy of asymptomatic cases may result in renovascular hypertension and renal failure. The reduction of renal function in these patients might be decreased or stopped by early appropriate diagnosis and also might be treated with renal artery angioplasty or surgery, after medical management. There is a debate about the occurrence of ischemic nephropathy as a result of atherosclerotic renal artery stenosis. In this study we aimed to review the prevalence of ischemic nephropathy due to atherosclerotic renal artery stenosis.
- انتشار مقاله: 05-12-1392
- نویسندگان: Reza Ghadimi,Alireza Abdollahi Moghadam,Marzieh Rahimzadegan
- مشاهده
- جایگاه : پژوهشی
- مجله: Reviews in Clinical Medicine
- نوع مقاله: Journal Article
- کلمات کلیدی: Renovascular hypertension,Atherosclrotic renal artery stenosis,Ischemic nephropathy,Renal artery angioplasty
- چکیده:
- چکیده انگلیسی: Ischemic nephropathy is defined as a clinically significant progressive reduction in glomerular filtration rate that is usually associated with significant renal artery stenosis (unilateral or bilateral involvement). Atherosclerotic renal artery disease is known as the most common cause of the ischemic nephropathy. These patients may develop secondary hypertension. In addition, epidemiologic data has showed a clear association between atherosclerotic renal artery stenosis and coronary artery disease and other cardiovascular disease. Despite the preserving function of kidney on various autoregulation processes, unusual microvascular function will be resulted due to sustained decline in renal perfusion. The ischemic nephropathy of asymptomatic cases may result in renovascular hypertension and renal failure. The reduction of renal function in these patients might be decreased or stopped by early appropriate diagnosis and also might be treated with renal artery angioplasty or surgery, after medical management. There is a debate about the occurrence of ischemic nephropathy as a result of atherosclerotic renal artery stenosis. In this study we aimed to review the prevalence of ischemic nephropathy due to atherosclerotic renal artery stenosis.
- انتشار مقاله: 05-12-1392
- نویسندگان: Reza Ghadimi,Alireza Abdollahi Moghadam,Marzieh Rahimzadegan
- مشاهده
- جایگاه : پژوهشی
- مجله: Reviews in Clinical Medicine
- نوع مقاله: Journal Article
- کلمات کلیدی: Body Mass Index,Ventricular function,Roux-en-Y gastric bypass
- چکیده:
- چکیده انگلیسی: Introduction: Weight gain and obesity are two important public health problems, which are associated with many diseases such as cardiovascular disorders. Various policies such as bariatric surgery have been proposed for the treatment of morbid obesity.
Methods: PubMed and Scopus were searched thoroughly with the following search terms (roux-en-y gastric bypass surgery) AND (ventricular function, OR cardiac risk factors OR heart)) AND (BMI OR body mass index) to find the articles in which the effect of roux-en-Y gastric bypass (RYGB) surgery had been evaluated in severely obese patients.
Result: Out of 120 articles which were found in PubMed, and 28 records which were found in Scopus, only 18 articles fully met the inclusion criteria. Out of 2740 participants in the included studied, 1706 were patients with body mass index (BMI) over 40 kg/m2 who had undergone RYGB surgery, and 1034 were control participants. Results of the studies showed that RYGB surgery could reduce BMI, and cardiac risk factors, and improve diastolic function, systolic and diastolic blood pressures, and aortic function, postoperatively.
Discussion: Obesity is associated with increased risk of cardiovascular diseases, impaired cardiac function, and hypertension. It is shown that RYGB surgery reduces the serum level of biochemical markers of cardiac diseases. Cardiac structure, parasympathetic indices of autonomic function, coronary circulatory function, hypertension, epicardial fat thickness, and ventricular performance improve after bariatric surgery.
Conclusions: It is concluded that RYGB surgery is an effective strategy to improve ventricular function and cardiac risk factors in morbid obese patients.- انتشار مقاله: 19-12-1393
- نویسندگان: Alireza Abdollahi Moghaddam,Ali Jangjoo,Fereshteh Ghaderi,Majid Erfanzadeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Ultrafine Grained and Nanostructured Materials
- نوع مقاله: Journal Article
- کلمات کلیدی: Aluminum Matrix Composites,ultra-fine grained materials,trimodal composites,carbides
- چکیده:
- چکیده انگلیسی: In this study, ultrafine grained 2024 Al alloy based B4C particles reinforced composite was produced by mechanical milling and hot extrusion. Mechanical milling was used to synthesize the nanostructured Al2024 in attrition mill under argon atmosphere up to 50h. A similar process was used to produce Al2024-5%wt. B4C composite powder. To produce trimodal composites, milled powders were combined with coarse grained aluminum in 30 and 50 wt% and then were exposed to hot extrusion at 570°C. The microstructure of hot extruded samples were studied by optical microscope, Transmission electron microscope (TEM) and scanning electron microscope (SEM) equipped with EDS spectroscopy. The mechanical properties of samples were compared by using tensile, compression and hardness tests. The results showed that the strength, after 50 h milling and addition of 5wt% B4C, increased from 340 to 582 MPa and the hardness increased from 87 HBN to 173 HBN, but the elongation decreased from 14 to 0.5%. By adding the coarse-grained aluminum powder, the strength and hardness decreased slightly, but the increases in return. Ductility increase is the result of increase in dislocation movements and strength increase is the result of restriction in plastic deformation by nanostructured regions. Furthermore, the strength and hardness of trimodal composites were higher, but their ductility was lower.
- انتشار مقاله: 15-02-1393
- نویسندگان: Alireza Abdollahi,Ali Alizadeh
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Pharmaceutical Sciences
- نوع مقاله: Journal Article
- کلمات کلیدی: Staphylococcus aureus,Susceptibility,Resistance,Antimicrobials
- چکیده:
- چکیده انگلیسی: Staphylococcus aureus is a major bacterial pathogen that causes different community- and hospital-acquired infections. Over time, strains of S. aureus have become resistant to different antibiotics including penicillinase-resistant penicillins. Having data on the local antimicrobial susceptibility pattern of this pathogen is necessary for selection of appropriate antibiotics for empirical treatment of infections due to it. To determine the antimicrobial susceptibility pattern of Staphylococcus aureus strains isolated from hospitalized patients in Tehran, Iran, In a prospective cross-sectional study performed at Imam Khomeini Hospital, samples were collected from hospitalized patients and were cultured. All positive cultures which yielded S. aureus underwent antimicrobial susceptibility testing using the Kirby-Bauer disk diffusion method on Mueller-Hinton agar. The results were interpreted after 24 hours of incubation at 37 °C. A total of 160 clinical isolates of S. aureus were collected. Most isolates were obtained from blood (29%). The overall susceptibility of isolated S. aureus strains to antimicrobial agents was 100% for vancomycin, 49.4% for amikacin, 43.8% for gentamicin, 36.8% for co-trimoxazole and tetracycline, 36.3% for cefazolin, 30.6% for cephalexin, 24.4% for oxacillin, 23.8% for erythromycin, and 3.1% for penicillin. Other than vancomycin, none of the tested antibiotics are appropriate for empirical treatment of serious S .aureus infections in our area.
- انتشار مقاله: 29-04-1388
- نویسندگان: Hossein Khalili,Rasoul Soltani,Kheirollah Gholami,Mehrnaz Rasoolinejad,Alireza Abdollahi
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Pathology
- نوع مقاله: Journal Article
- کلمات کلیدی: COVID-19,Pathology,coronavirus,Electronic exams
- چکیده:
- چکیده انگلیسی: Background & Objective: The world is facing COVID-19 pandemic, and medical education system and consequently the evaluation of students at different levels have been overshadowed. Residency students are among those affected. In the present study, we aim to share our experiences regarding holding exams for pathology residents before and during the pandemic.
Methods: This cross-sectional study was carried out in Tehran University of Medical Sciences. The online exam, which consisted of 30 multiple-choice questions, was designed and held in April 2020 to evaluate pathology residents. To assess the quality of the exam, indices such as the number of questions, highest and lowest scores, the average score, the standard deviation, the variance, Cronbach’s alpha reliability coefficient, standard error of measurement, discrimination index, difficulty index, number/percentage of questions on three difficulty levels of easy, normal, hard were reviewed and analyzed.
Results and Discussion: The average score of the participants in the January exam which was held in the university’s exam center was 16.23 (±5.03), while the average score in the online exam which was held after the onset of the pandemic was 20.86 (±5.18). The average discrimination indices in the first and second exams were 0.36 and 0.38, respectively, and the average difficulty indices in the first and second exams were 0.54 and 0.70, respectively. We found the administration of this online examination would be a positive experience. By sharing it, we hope to pave the way for similar ventures in the other departments.- انتشار مقاله: 31-03-1399
- نویسندگان: Alireza Abdollahi,Ali Labbaf,Mahboobeh Mafinejad,Maryam Sotoodeh-Anvari,Farid Azmoodeh-Ardalan
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Pathology
- نوع مقاله: Journal Article
- کلمات کلیدی: Iran,Squamous Cell Carcinoma,human papillomavirus
- چکیده:
- چکیده انگلیسی: Background & Objective: Human papillomavirus (HPV) has been associated with prognosis in patients with head and neck squamous cell carcinoma (HNSCC). Similar to the global studies, different prevalence rates of this viral infection have been reported in Iran. Therefore, we aimed to report the prevalence of this virus and its significance in HNSCC patients.
Methods: Patients who were referred to the five hospitals of Tehran city from May 2018 to May 2019 were enrolled in this study. All patients were diagnosed with HNSCC based on pathologic study. The pathologic disease staging was defined, and DNAs were extracted from the fresh tissue samples via kits. After polymerase chain reaction (PCR), HPV positive samples were evaluated for determining genotypes and data analysis.
Results: Of the 46 patients, three patients (6.5%) had positive HPV with the following subtypes: 18 (in two patients), 52 (in three patients), 61 (in two patients), 67, and 73.
Comparison of variables between the groups with and without HPV showed a significant difference based on the tumor’s lymphatic invasion (p =0.041), peripheral lymph node involvement (p =0.008), and histologic grade (p =0.011), but there was no statistically significant difference in terms of other variables such as age, primary tumor site, size, pathologic stage, vascular or perineural invasion, metastasis, smoking, and alcohol consumption.
Conclusion: HPV positivity is an important factor in the lymphatic invasion, peripheral lymph node involvement, and histologic grade of cases with HNSCC and should be further investigated for its effect on prognosis.- انتشار مقاله: 17-10-1398
- نویسندگان: Mitra Rezaei,Mahboobeh Karimi-Galougahi,Azin Kheradmand,Mihan Pourabdollah Toutkaboni,Hassan Mir Mohammad Sadeghi,Alireza Abdollahi,Amirnader Emami Razavi,Ali Safavi Naini,Farahnaz Bidari- Zerehpoosh
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Pathology
- نوع مقاله: Journal Article
- کلمات کلیدی: Breast cancer,Metastasis,Gelsolin,Villin
- چکیده:
- چکیده انگلیسی: Background & Objective: Nowadays, actin-binding proteins such as Villin and Gelsolin have been considered to be associated with aggressive tumors. This study mainly aims to determine the relationship between Gelsolin and Villin genes expression and metastasis of axillary lymph nodes in patients with breast cancer.
Methods: The included population consisted of 40 confirmed cases of female breast cancer (including 20 patients with breast cancer along with axillary lymph node metastasis and 20 patients without axillary lymph node metastasis). Expression of Villin and Gelsolin genes was evaluated using Real-time PCR and pre-designed primers.
Results: The mean expression level of Villin in groups with and without axillary lymph node metastasis was 3.33±1.35 and 0.87±0.88, respectively (p <0.001). The mean Gelsolin expression levels in both groups (with and without axillary lymph node metastasis) were 4.13±2.40 and 1.00±0.35, respectively (p <0.001). The significant relationships were independent of individuals’ age.
Conclusion: Patients with axillary lymph node metastasis may express significant higher level of Villin and Gelsolin gens.- انتشار مقاله: 23-11-1398
- نویسندگان: Armin Borhan,Zohreh Nozarian,Alireza Abdollahi,Reza Shahsiah,Hadiseh Mohammadpour,Arash Borhan
- مشاهده