Application of impulse damper in control of a chaotic friction-induced vibration

Mansour Ataei,Ali Asghar Atai,Sajjad Mirjavadi,Mohammad Sahebnasagh,Mansour Nikkhah-Bahrami 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.2

Friction-induced vibration is an important phenomenon with adverse effects on many dynamic systems involving friction. In this study,a very simple and well-known one-dimensional friction-induced dynamic system is considered in which the novel PZT stack impulse damper is incorporated into the system. It has been shown that by appropriately tuning the damping parameters, the chaotic behavior is removed quickly and efficiently. It has also been demonstrated that the system is sensitive to parameter change, and minimal modification of these parameters can revert the chaotic or periodic motion.

Knowledge about Gastric Carcinoma in North of Iran, A High Prevalent Region for Gastric Carcinoma: A Population-Based Telephone Survey

Mansour-Ghanaei, Fariborz,Joukar, Farahnaz,Soati, Fatemeh,Mansour-Ghanaei, Alireza,Naserani, Sara Bakhshizadeh Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Background & Objectives: The most northern and northwestern regions of Iran are at a high risk for gastric cancer. The aim of this study was to assess the general population's awareness about risk factors, symptoms and signs, preventive methods and management of gastric carcinoma in a high prevalence city in the North of Iran. Methods: A cross-sectional population-based telephone survey which was conducted on 3,457 residents of Rasht, the capital city of Guilan Province, to assess their awareness regarding gastric carcinoma. The questionnaires contained demographic data and statements on respondents' knowledge about risk factors, symptoms and signs, prevention and management of gastric cancer which were filled by general practitioners after asking the subjects. Data were analyzed in SPSS14. P<0.05 was considered significant. Results: The mean knowledge score of the respondents was $5.05{\pm}1.37$ regarding risk factors of gastric carcinoma, $4.39{\pm}1.99$ regarding symptoms and signs, $6.0{\pm}1.22$ regarding preventive strategies, and $1.6{\pm}1.16$ regarding management. Totally the mean knowledge level of the respondents toward gastric carcinoma would be $17.1{\pm}3.97$ from the maximum grade of 29. The age group of 45-55 y/o, bachelor degree and higher, physicians and nurses, those who had cancer history in friends or had the history of gastrointestinal diseases showed significantly higher knowledge scores (P=0.001). Conclusion: There is a general lack of awareness of cancer risk factors, symptoms and signs, methods of prevention, and importance of early diagnosis and treatment. Educational programs should be developed to promote adherence to recommended screening guidelines.

Knowledge about Colorectal Cancer in Northern Iran: a Population-Based Telephone Survey

Mansour-Ghanaei, Alireza,Joukar, Farahnaz,Mansour-Ghanaei, Fariborz,Rasoulian, Javid,Naghipour, Mohammad Reza,Fani, Arezoo,Kazemnejad, Ehsan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.17

Background: Colorectal cancer (CRC) is one of the most common malignancies of the gastrointestinal tract. The aim of this study was to assess the general knowledge of CRC in individuals living in Rasht, Iran, using a population-based cross-sectional telephone survey. Materials and Methods: A total of 1557 participants between 18 and 80 years of age were interviewed using random sampling from the telephone directory. Knowledge of risk factors, symptoms, diagnosis, and prevention of CRC was assessed using a validated questionnaire. Results: The mean knowledge level of the 1,557 respondents (average age 46 y) was $13.5{\pm}4.29$ (maximum possible score = 26), and 46.4% (722/1,557) of the subjects achieved grades lower than the mean score. The mean scores for knowledge of symptoms and risk factors were $3.97{\pm}1.83$ (range: 0-7) and $5.17{\pm}1.65$ (range: 0-9), respectively. Older age, higher education, and employment were significantly associated with better scores for recognition of risk factors and warning symptoms. The majority of subjects correctly identified weight loss (70.2%; 1,093/1,557) and rectal bleeding (63.3%; 986/1,557) as symptoms of CRC, and that smoking (85.9%; 1,337/1,557) and a low-fiber diet (73.4%; 1,143/1,557) were risk factors. Approximately half of the subjects noted increasing age, genetic background and fried food as other risk factors. A considerable number (54.8%; 853/1,557) identified colonoscopy as a screening method for detecting CRC in asymptomatic patients. However, a third of the subjects in the target group for screening (${\geq}50y$) were not interested in undergoing screening, primarily due to a lack of symptoms. Conclusions: Our results suggest that the knowledge of CRC is poor among the public, and therefore greater attempts should be made to increase awareness. Public education emphasizing the risk factors and symptoms of CRC, as well as the importance of regular screening regardless of the presence of symptoms, may help to reduce CRC morbidity and mortality.

Outcome of Intestinal Metaplasia in Gastric Biopsy of Patients with Dyspepsia in Guilan Province, North Iran

Mansour-Ghanaei, Fariborz,Joukar, Farahnaz,Soati, Fatemeh,Mansour-Ghanaei, Alireza,Atrkar-Roushan, Zahra Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6

Background: It is generally accepted that gastric carcinomas are preceded by a sequential multistage process that includes chronic gastritis, gastric atrophy, usually with intestinal metaplasia (IM), and dysplasia. This series of changes in gastric carcinogenesis is often initiated by Helicobacter pylori (H pylori) infection. The aim of the present study was determination of gastric histopathologic changes in IM patients after at least one year in Guilan province, Iran. Materials and Methods: This case-series study was conducted in Guilan Gastrointestinal and Liver Disease Research Center (GLDRC) during 2010 to 2011. Gastric biopsy was performed for all 71 known cases of IM and precanceric lesions including gastric atrophy, IM, dysplasia and H pylori infection were determined after at least one year. Results: Of the total of 71 patients with established IM who were enrolled, 50 had complete-type IM and 21 had incomplete-type IM. Fifty two people had H pylori infection. H pylori eradication was achieved in 39 patients (75%). Secondary pathology findings of patients with IM were complete metaplasia (39.4%), incomplete metaplasia (32.4%), dysplasia (23.9%) and other precanceric lesions (4.2%). Dysplasia (20%vs 33%) occurred in patients who had complete and incomplete IM at baseline respectively (p>0.05). Age, gender, family history of gastric cancer(GC); smoking habits and NSAIDs use were not associated with gastric premalignant lesions in initial and secondary pathologies (p>0.05). The difference became statistically significant between H pylori infection in patients with more than 3 years diagnostic intervals (p<0.05). Statistical difference between eradicators and non-eradicators was not significant. Conclusions: We found that incomplete IM increased the risk of subsequent dysplasia in this study.

Should all patients with hypertension be worried about developing severe coronavirus disease 2019 (COVID-19)?

Bahardoust Mansour,Goharrizi Mohammad Ali Sheikh Beig,Bahardoust Mansour,Alvanegh Akbar Ghorbani,Ataee Mohammad Reza,Bagheri Mehdi,Navidiyan Ensiyeh Shabani,Zijoud Seyed Reza Hosseini,Heiat Mohammad 대한고혈압학회 2021 Clinical Hypertension Vol.27 No.2

Background: Hypertension, the most common comorbidity among coronavirus disease 2019 (COVID-19) patients, is accompanied by worse clinical outcomes, but there is lack of evidence about prognostic factors among COVID19 patients with hypertension. We have come up with some prognostic factors to predict the severity of COVID-19 among hypertensive patients. In addition, epidemiologic, clinical and laboratory differences among COVID-19 patients with and without underlying hypertension were evaluated. Methods: Medical profiles of 598 COVID-19 cases were analyzed. Patients were divided into two comparative groups according to their positive or negative history of hypertension. Then, epidemiologic, clinical, laboratory and radiological features and also clinical outcomes were compared. Results: 176 (29.4%) patients had underlying hypertension. Diabetes was significantly higher in hypertensive group [72 (40.9%) vs 76 (18%)] (P-value: 0.001). Cardiovascular and renal disorders were significantly higher in hypertensive patients. (P-value: 0.001 and 0.013 respectively). In COVID-19 patients with hypertension, severe/critical types were significantly higher. [42(23.8%) vs. 41(9.7%)], (P-value: 0.012). In the logistic regression model, Body mass index > 25 (ORAdj: 1.8, 95% CI: 1.2 to 2.42; P-value: 0.027), age over 60 (ORAdj: 1.26, 95% CI: 1.08 to 1.42; P-value: 0.021), increased hospitalization period (ORAdj: 2.1, 95% CI: 1.24 to 2.97; P-value: 0.013), type 2 diabetes (ORAdj: 2.22, 95% CI: 1.15 to 3.31; P-value: 0.001) and chronic kidney disease (ORAdj: 1.83, 95% CI: 1.19 to 2.21; P-value: 0.013) were related with progression of COVID-19. Conclusion: Hypertensive patients with Age > 60-year-old, BMI > 25 Kg/m2 , CVD, diabetes and chronic kidney disease are associated with poor outcomes in those with COVID-19 infection.

Maxillofacial reconstruction with Medpor porous polyethylene implant: a case series study

Mansour Khorasani,Pejman Janbaz,Farshid Rayati 대한구강악안면외과학회 2018 대한구강악안면외과학회지 Vol.44 No.3

Objectives: The role of alloplastic materials in maxillofacial reconstruction is still controversial. Determining the utility of porous, high-density, poly-ethylene implants as a highly stable and flexible, porous alloplast, with properties such as rapid vascularization and tissue ingrowth, is crucial in cases of maxillofacial deformities and aesthetic surgery. Materials and Methods: Thirty high-density porous polyethylene implants were implanted in 16 patients that had been referred to a private office over a three-year period. These implants were used for correcting congenital deformities, posttraumatic defects and improving the aesthetic in nasal, paranasal, malar, chin, mandibular angle, body and orbital areas. Results: The outcomes of the cases in this study showed good aesthetic and functional results. The majority of patients had no signs of discomfort, re-jection or exposure. Two implants suffered complications: a complicated malar implant was managed by antibiotic therapy, and an infected mandibular angle implant was removed despite antibiotic therapy. Conclusion: Based on the results, the Medpor implant seems to be an excellent biomaterial for correcting various facial deformities. Advantages in-clude its versatility and relatively ideal pore size that allows for excellent soft tissue ingrowth and coverage. It is strong, flexible and easy to shape.

ABSOLUTELY PURE REPRESENTATIONS OF QUIVERS

Mansour Aghasi,Hamidreza Nemati 대한수학회 2014 대한수학회지 Vol.51 No.6

In the current paper we study absolutely pure representa- tions of quivers. Then over some nice quivers including linear quivers some sufficient conditions guaranteeing a representation to be absolutely pure is characterized. Furthermore some relations between flatness and absolute purity is investigated. Finally it is shown that the absolutely pure covering of representations of linear quivers (including A-∞, A+∞ and A∞∞) by R-modules whenever R is a coherent ring exists.

Clinical evaluation of autologous fat graft for facial deformity: a case series study

Mansour Khorasani,Pejman Janbaz 대한구강악안면외과학회 2021 대한구강악안면외과학회지 Vol.47 No.4

Objectives: The use of fat grafts in maxillofacial sculpturing is currently a common technique. Unlike fillers, autologous fats unite with facial tissues, but long-term results may still be unsatisfactory. Sharing long-term follow-ups can be helpful in making outcomes more predictable. Materials and Methods: The data from patients who were admitted from 2014 to 2016 for fat augmentation were collected. In all cases, fat grafts were injected by blunt cannula using a tunneling technique in different planes. A fan shape order for the malar, periorbital, nasolabial fold, mandibular angle and body, and perioral area was established. Results: Autologous fat was used for different sites of the maxillofacial regions. Of 15 patients, two patients were not satisfied due to fat graft resorption. For this, further injections were performed six months after the first injection using preserved fat grafts. One patient continued to be dissatisfied. There were no other complications related to fat transplants. Conclusion: Fat transplantation is a safe, reliable, and non-invasive method for facial contour and facial soft tissue defect restoration. Additional methods such as mesenchymal stem cells along with fat injection increase the survival rate of transferred fat.

Modeling and nonlinear analysis of a micro-switch under electrostatic and piezoelectric excitations with curvature and piezoelectric nonlinearities

Mansour Nikkhah Bahrami,Aghil Yousefi-Koma,Hamed Raeisifard 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.1

In this paper, a comprehensive model of a micro-switch with both electrostatic and piezoelectric excitations, which accounts for thenonlinearities due to inertia, curvature, electrostatic forces and piezoelectric actuator is presented to demonstrate the mechanical characteristicsof such a micro-system. Dynamic equations of this model are derived by the Lagrange method. Static analysis of this model is performedwith five modes through the Galerkin method. The micro-switch beam is assumed as an elastic Euler-Bernoulli beam withclamped-free end conditions. The electrostatic actuation results are compared with other existing experimental and numerical results. Whereas the major drawback of electrostatically actuated micro-switches is the high driving voltage, using the piezoelectric actuator inthese systems can provide less driving voltage and control the pull-in voltage. The study demonstrates that when the ratio of electrostaticactuation distance to length of micro-switch is small, the nonlinear piezoelectric term has a significant effect on the pull-in phenomenon. There are three ways to influence the design and control of the mechanical characteristics of this micro-switch: the softening effect due toelectrostatic actuation, the hardening effect due to piezoelectric actuation, and varying the length and thickness of the piezoelectric actuator.

Synthesis and Antiproliferative Potency within Anticonvulsant of Novel Bichalcone Derivatives

Mansour, Eman,El-Badry, Yaser A.,El-Tokhy, Afaf,Ayyad, Rezed,Abd-Rabou, Ahmed A. Korean Chemical Society 2020 대한화학회지 Vol.64 No.1

An efficient and facile procedure has been developed for the synthesis of novel bichalcone derivatives (4a, 4b). The key step contains the solvent-free aldol synthesis of bichalcones based on quinones. Bichalcones (4a, 4b) were used as precursors for the synthesis of some interesting heterocyclic compounds like, diazepines (5a, 5b), pyrazolo-pyrimidines (7a, 7b), and pyrazoline derivatives (8a, 8b). Moreover, new thioxopyrimidine derivatives (9a, 9b) were furnished and used as a functionalizing agent to produce the triazole-pyrimidines (11, 12) and the carbonitrile derivative (14). All the synthesized compounds were fully characterized using physical and spectral data like, FT-IR, ¹H NMR, ¹³C NMR, and MS. Bichalcones (4a, 4b) and diazepines (5a, 5b) were screened for their anticonvulsant activity, where compounds (4a, 5a, and 5b) revealed potent anticonvulsant activity compared to diazepam. On the other hand, some of the prepared compounds were screened for their antiproliferative activity and they showed significant cytotoxic effects on most of the cancer cell lines with regard to broad spectrum antitumor activity.