فهرست مطالب عباس محمدی

The present study aimed to assess the prevalence of musculoskeletal problems related to mobile phone usage and provide corrective solutions for dental students of Jundishapur University of Medical Sciences, Ahvaz.

The current study was conducted based on an analytical cross-sectional design. In order to collect relevant data, such as the presence of pain in the upper limbs, back, and neck, questionnaires and instrumental methods were used. Students were examined in two groups: the first group included 150 dental students up to the 4th semester, and the second group encompassed 150 dental students from the 5th semester onwards (3rd, 8th, 5th, and 6th year). Data collection instruments were demographic characteristic form, nomophobia questionnaire (NMP-Q), neck disability index (NDI), and Cornell hand discomfort questionnaire (CHDQ).

According to the results of the present study, the prevalence of nomophobia among dental students of Jundishapur University of Medical Sciences in Ahvaz was at an average level. The mean  NDI score was 16.20, and the mean pain score among the students was 72. 1. Moreover, 46.5% of students had pain in the hand area, and the highest amount of pain was reported in the F area. The mean score of Cornell's musculoskeletal disorders was reported as 2.72.

Examining the relationship between the pain area and the year of entry to the university demonstrated a significant relationship between the year of entry to the university and the pain area. In this regard, the incoming students 2021-22 had the greatest amount of pain. According to the results of the corrective intervention on skeletal disorders in the wrist and neck region, the mean scores of the variables increased significantly after the intervention and corrective measures.

Musculoskeletal disorders (MSDs) are widespread and important health and social problems in industrialised society, reducing productivity, increasing treatment costs and affecting the quality of life of workers. The present study was conducted with the aim of investigating the effects of workload, fatigue, sleep quality and physical condition on musculoskeletal disorders among workers in the steel industry.

The present study is a descriptive and analytical study conducted on a population of 540 workers working in the steel industry in the city of Dezful. Based on simple random sampling, 400 people were selected as samples. The instruments used in this study are the Demographic Information Questionnaire, the Cornell Musculoskeletal Disorders Questionnaire (CMDQ), the Swedish Occupational Fatigue Inventory(SOFI), the Pittsburgh Sleep Quality (PSQI) and the NASA-TLX workload index. The Rapid Entire Body Assessment (REBA) was used. Descriptive statistical indices were used to analyze the data, and the relationships between observed and hidden variables were examined using structural equation modeling (SEM) The data were analyzed at a significance level of 0.05 and in SPSS software version 25.

According to the prevalence of musculoskeletal disorders, back pain ranked first with a mean and standard deviation of 52.39±25.44 and knee pain ranked second with a mean and standard deviation of 46.46±26.45, indicating that the prevalence of these disorders is high among steel industry workers. The results of the correlation analysis showed that there is a positive and significant relationship between workload, fatigue, sleep quality and body condition and musculoskeletal disorders (p<0.05). The RMSEA index of less than 0.1 shows that the model proposed in this study fits well and demonstrates the role of workload variables, fatigue, sleep quality and body position in the direct and indirect causation of musculoskeletal disorders.

The results of this study show that improving workplace ergonomics, reducing workload and fatigue, and improving sleep quality can reduce the likelihood of musculoskeletal disorders in workers.

Cargo workers at Ahvaz Airport in Ahvaz, Iran are at risk of musculoskeletal disorders. In this regard, the present study aimed to investigate their carrying out tasks and postures.

In this descriptive-analytical study, the census method was used to select 21 cargo workers in Ahvaz Airport. Task analysis was carried out by Hierarchical Task Analysis (HTA) and Quick Exposure Check (QEC). Moreover, the Manual Handling Assessment Charts were used to evaluate the manual load. The tools employed in this study included observation, photography, and a Cornell Musculoskeletal Disorder Questionnaire (CMQD) questionnaire. Statistical calculations were performed in SPSS (version 16) and Spearman's correlation coefficient for the variables.

Each of the cargo workers of Ahvaz airport moves an average of 400 bags per shift. Spearman's correlation coefficient showed a significant relationship between musculoskeletal disorders and the variables of age, height, and Body Mass Index with values of 0.002, 0.005, and 0.003, respectively. The QEC method was used to observe the worst postures with a numerical score between 50 and 70, which were related to the standing posture at the flat roller and the sitting posture in the aircraft cargo. The examination of the CMQD questionnaire revealed that 61.6%, 65%, and 62% of diseases were related to shoulder, arm, and back, respectively.

After job analysis by the HTA method and evaluation of the results through the QEC method, it was determined that loading and arranging luggage in the cart and cargo were the most risky tasks. Both the MAC and QEC methods also indicated the necessity of an immediate change in the process of moving luggage.

Naphtha cracking processes call for low aromatic feedstocks to satisfy the operational considerations regarding the quality of their feedstocks. Therefore, the issue of the aromatics removal from petroleum fractions has become more serious. In this study, the experimental investigation and thermodynamic modeling of the liquid-liquid equilibria of the quinary system naphtha cut (including paraffinic, naphthenic, and aromatic species), sulfolane, and water, over the temperature range of 303.2 to 333.2 K, have been studied. The molecular representatives of paraffinic, naphthenic, and aromatic species of naphtha cut have been determined based on different objective functions. Physical properties estimation and modeling of equilibrium data reveal higher accuracy of vapor pressure- and viscosity-based objective functions in the structural modeling of naphtha cut. The root-mean-square deviations for the mentioned functions were determined to be about 1.47 and 1.48%, respectively. Thermodynamic modeling with the predictive UNIFAC model showed a good agreement with the experimental measurements. Also, the interaction coefficients extracted from the 75 ºC equilibrium data led to minimum deviation in the equilibrium modeling. Finally, the phase diagrams show the noticeable effect of water content and the small effect of temperature on the system equilibria.

Teachers have the main role in conveying educational content to students, and therefore, the development of their professional dimensions is inevitable for career advancement. The purpose of this research was to design and validate the self-development model of Iranian television school teachers.

The present research method was quantitative-survey and practical in terms of purpose. The statistical population included the teachers of Iran's elementary television school who taught on the Quran and Education Network during the Corona epidemic (161 people), and based on Cochran's formula, 113 people were selected as available sampling methods. The research tool was a researcher-made questionnaire based on qualitative interviews and theoretical literature. Face validity was used for validity and Cronbach's alpha test was used for reliability, and its value was 0.83. For data analysis, confirmatory factor analysis was used with the help of PLS ​​Smart software.

The findings showed that the path coefficient between value-attitude self-development in education and teaching and teachers' self-development is 0.704; between the self-directed learning of television school teachers and the self-development of teachers 0.712; The correlation between cognitive self-development in education and teaching and teachers' self-development was 0.745, between TV school teachers' self-development stimuli and teachers' self-development was 0.573, and between skill self-development in education and teaching and teachers' self-development was 0.640 (P<0.05).

It can be concluded that the self-development model of Iranian television school teachers is valid and the planners of the education system can pay attention to these results to improve the quality of teachers' self-development.

In order to improve the process of selection and appointment of ministerial administrators in education, the design, and validation of a competency model was deemed necessary. To this end, a sample of 22 experts was interviewed and their responses were content analyzed. Additionally, a sample of 86 ministerial administrators from among 115 such individuals in Tehran were given a questionnaire with an acceptable validity. These data were analyzed through factor analysis. Results brought about an initial list of 63 competencies of which 58 were confirmed through factor analysis. These competencies are categorized in two dimensions of general and special with six main categories and 17 subcategories.

Today, resilience is a topic that has attracted increasing interest in the business space. Uncertainty about the future, changes, developments and environmental risks have endangered the survival of today's organizations. Managers of most organizations believe that the resilience of businesses plays an important role in enabling them to invest, sell, market, trade, etc. in the future. On the other hand, the lack of a systematic and efficient study and the existence of a model about the resilience of small and medium businesses in internal and external research has become the main problem of the managers of these companies. Therefore, in this research, the factors affecting the resilience of companies have been investigated in order to adopt effective strategies in order to prevent and prevent disruptions and reduce the performance of companies using system dynamics methods. Considering the importance of the development of small and medium-sized companies in the current state of the country from the economic, security, political, health and other situations, it is necessary to prevent financial and functional helplessness and bankruptcy, therefore, the findings of this research include identifying the factors that contribute to the resistance of small and medium-sized companies with Considering environmental drivers and impulses are effective and presenting a conceptual and operational model of organizational resilience. The research method of the current research is practical in terms of its purpose and it is exploratory in terms of data collection, and the type of research data is qualitative and quantitative.

The present study sought to re-engineer the structure and content of the "Philosophical Schools and Educational Opinions" course syllabus of the master's degree in the major of History and Philosophy of Education. This was done with the purpose of investigating new content with an emphasis on the Islamization of humanities courses in the Iran universities. In this research a combined method with a sequential exploratory approach was employed. First, in the qualitative stage, using the method of document analysis, the current state of construction and the content of the curriculum of Philosophical Schools and Educational Opinions in leading domestic and foreign universities in the field of educational philosophy such as America, Australia and Canada were investigated. This was done with the aim of analyzing and discovering the nature of the educational field in the field of Philosophical Schools and Educational Opinions. Then, according to the descriptive-survey method and the viewpoints obtained from the statistical sample under study, two types of separate questionnaires were created by the researcher, and their reliability was estimated using the "Cronbach's alpha" formula as 0.953 and 0.896 percent, respectively. The research sample included 76 faculty members by census, and 290 students of domestic universities; state, Azad, and Payam Noor randomly clustered. New content for the mentioned course was determined. Finally, regardless of the cultural roots of the curriculum in question in the leading countries and its significant content and conceptual difference with Iranian universities, the findings of this study show that the current situation of "structure" and "content" in the studied curriculum do not meet the current conditional needs and are not in accordance with the Islamic needs of the students, and it is recommended to make changes in the structure and major concepts of the course "Philosophical Schools and Educational Opinions" according to the proposed model based on the present research.

The present research has studied the performance of a mixed solvent of sulfolane and 3-methyl-N-butylpyridinium dicyanimide to dearomatize the naphtha fraction of the Tehran oil refinery. Analysis of variance and artificial neural network analysis (as a standard multi-layer perceptron network) reveals that regarding the solvent selectivity, degree of product paraffinicity, and the production yield of dearomatized product, ionic liquid content in the mixed solvent has the highest degree of importance among design variables, whereas, the solvent-to-feed ratio is the most effective one in the solvent capacity response. The findings show the negligible effect of the extraction temperature and the absence of positive and negative synergistic effects between sulfolane and 3-methyl-N-butylpyridinium dicyanimide. Considering the penalty function approach and different single-objective and multi-objective functions, the optimum values of the solvent-to-feed ratio and the ionic liquid content were found as 2.03:1 and 99.47%. As a rough estimate, the mixed solvent leads to a 47% decrease in the required amount of solvent compared to the sulfolane solvent.

This study has examined the extractive dearomatization of naphtha cracker feedstock. By considering the solvent-to-feed ratio (2:1-4:1), solvent water content (0-10 wt.%), and extraction temperature (30-60 ºC) as major operating variables and the solvent capacity, solvent selectivity, and the yield and the degree of paraffinicity of the dearomatized fraction as the response of experiments, the priority of variables in the prediction models was determined. The analysis of variance and a standard multilayer perceptron artificial neural network showed that in extractive dearomatization of the blended naphtha cut with sulfolane solvent, the priority of variables follows the trend of solvent water content, solvent-to-feed ratio, and temperature. Also, by optimizing the operation, using the penalty function approach, and defining six different single- and multi-objective functions, the optimum values of the solvent water content, solvent-to-feed ratio, and extraction temperature were found as 9.98%, 3.86:1, and 32.6 oC, respectively. Finally, the maximum values for the degree of paraffinicity and the yield of the dearomatized fraction were obtained as 94.36 and 95.95%, respectively.

Today, the specialists’ attention on polyurethanes is increasing day by day due to easy synthesis, available raw materials, favorable mechanical properties, biocompatibility, and the possibility of providing different products, such as water-based polyurethanes, foams, hydrogels and glues. Chitosan is a natural polymer that is extracted from the deacetylation of chitin and contains glucosamine and N-acetyl glucosamine units. This non-toxic natural polymer has very useful properties such as antimicrobial activity, biocompatibility, biodegradability, and tissue repair and regeneration effects. One of the weaknesses of chitosan is its poor solubility and processability due to its strong intra- and intermolecular hydrogen bonding. Therefore, chitosan has been used mainly in modified form or in combination with other polymers in various applications. The combination of synthetic polymers with natural polymers is of particular importance because natural polymers such as chitosan can show some properties such as biocompatibility, biodegradability, low toxicity, high cell viability, and internal tissue growth; while the synthetic polymers have other characteristics such as favorable processing, mechanical and physical properties, and appropriate chemical and thermal stability. Recently, chitosan has been used in combination with polyurethanes to improve its mechanical properties, thermal stability, biodegradability, antimicrobial properties and biological activity. During these studies, products in various forms such as composite, elastomer, fiber, foam, scaffold, and hydrogel have been prepared for different applications. In this review, polyurethanes containing chitosan and their synthesis methods for various applications are discussed. The products prepared in these studies have been suggested for various applications such as antibacterial coating, wound dressing, tissue engineering scaffold, fabric modification, fibers, hydrogels and foams.

Roads are one of the most critical assets of any country, and a large part of the country's budget is spent annually on repair and maintenance operations to eliminate cracks. One of the factors that can effectively increase the useful life of asphalt pavement is the self-healing potential of asphalt mixtures. This study considers the factors affecting the self-healing index (such as type of additive, percentage of additive, gradation of aggregate, type of bitumen, crack repair cycle, type of heating, and heating time), and using a neural network model to predict this index. For this purpose, multilayer perceptron neural network (MLP), m multilayer perceptron neural network with particle swarm optimized algorithm (PSO), radial basis function neural network (RBF), and statistical analysis with SPSS software were used, and the results of these methods were compared. The results showed that the multilayer perceptron neural network (MLP) with a correlation coefficient of 0.96 has a better performance in predicting the self-healing index than other methods and to evaluate the generalization power of the neural network using data that were not used during modelling, multilayer perceptron neural network (MLP) and radial basis function neural network (RBF) work best. Also, three samples were made in the laboratory by replacing 60% of steel slag with coarse aggregates (4.75-9.5 mm), and their self-healing results were evaluated with neural networks.

The Homotopy Analysis Method (HAM) was first proposed by Liao (1992) to solve functional equations. This method is based on homotopy and provides an approximate-analytical solution for functional equations. In recent years, this method and its modifications have been effectively used to solve a wide range of linear and nonlinear problems in applied sciences to find solutions to series of various types of nonlinear equations, including algebraic equations, ordinary differential equations, partial differential equations, and differential-integral equations (Abbasbandy et al. 2006). The purpose of this research is to provide an analytical solution of time delay with acceptable accuracy for the non-linear equation of non-Darcy flow in coarse-grained media using the HAM method, which previous researchers had recommended to conduct further research in this field.

In this research, the governing equation of the non-Darcy flow was solved by the HAM method for the first time, then the water level profiles of the final equation of the HAM method obtained for the 6 inlet flow rates with different boundary conditions and in two coarse-grained porous media including rounded and sharp-edged materials. The results of the water level profile using the HAM method have been compared with the laboratory data of Sedghi Asal (2010) reported at the Stuttgart laboratory in Germany. The normal objective function (NOF) has been used to compare the HAM method results with the experimental data of Sedghi Asal (2010).
 

The comparison of the results of HAM method with the experimental data of Sedghi Asal (2010) has been done under upstream and downstream boundary conditions for different discharges and with a slope close to the horizon S = 0.00001. The results have shown that flow rates of q=30 lit/s, with a NOF error percentage of 0.000099828 in the porous medium of sharp corners and q = 26.25 lit/s, with a NOF error percentage of 0.000102162 in the porous medium of round corners depict better accuracy than the experimental data in higher input flow rates. This method has logical solutions in horizon slopes and the water level profiles in HAM method and experimental data have coincided or are close to each other in most of the points. However, the subject of permanent and uniform flow needs a dependent research.

The results showed that the water level profiles are close to each other in most cases. This illustrates the accuracy of the developed approach based on HAM method. However, when the difference between the upstream and downstream water levels increases, the percentage of error escalates. In other words, with the increase of the hydraulic gradient in the porous medium, the error also grows. Finally, by evaluating the results of the HAM method compared to the laboratory data, it can be concluded that this method shows better accuracy in the porous medium with sharp-cornered materials compared to round-cornered materials due to higher flow rates and higher porosity of this media.

In any society, the course of social and cultural developments is undoubtedly influenced by the field of science and academic society. The educational system as a cultural tool not only supports and reinforces the society's culture but also serves as a reference to meet the needs of the society in the natural course of development. This research aims to explain the strategies for the transformation of the higher education system based on the statement of the second step of the revolution in order to achieve the indicators of a new generation of Islamic universities, which will be a reference for responding to the needs of the society in the development of the country. The research method is qualitative meta-combination. After searching for sources related to the topic, 21 sources related to keywords were selected from 374 primary sources, and then 109 primary codes were obtained using the qualitative method of document analysis. After refining and recategorizing the primary codes by the research team, two internal and external dimensions were obtained with 8 components and 21 indicators related to the evolution of higher education. The findings of this article consider higher education to be in need of "rethinking", "rebuilding structures" and "recreation" by using actions based on the statement of the second step, which are: jihadi management, scientific and technological jihad, economic jihad, media actions. Iranian-Islamic lifestyle, youthfulness, emphasis on participatory culture and compatibility in the functions of higher education, which must be continuously and operationally implemented, followed up and evaluated

Divorce and separation of parents are the main causes of mental illness in children. Therefore, it has been decided to examine the degree of fairness and justice of divorced children as one of these variables according to the following models and in the game the Dictator. Economic analysis is usually based on the assumption that people are completely interested in themselves and that they are looking to increase their personal gain. But in some economic experiments, there are evidences and phenomena that can not be interpreted and explained based on self-interest. In this model, people have fair tendencies and are sensitive to unequal results. In this article, at first the children of divorce and their moral characteristics have been introduced, then the game the Dictator and the model of Fahr and Schmidt (1999) has been introduced and analyze. To check the correctness of this model and its results in the case of divorced children, a two-person experiment in the form of a dictator game has been designed. This test was performed for male and female high school students in one of the cities of Iran. The results show that a significant proportion of divorced children choose between self-interest, between fairness and self-interest.

The skin, as the first defense barrier against the entry of pathogens into the body, helps to heal the wounds through four stages including homeostasis, inflammation, proliferation, and regeneration. Today, various wound dressings have been introduced to help the body's immune system to improve the speed and quality of wound healing. Conventional wound dressings include polyurethane foams and elastomers, hydrocolloids, hydrogels, semipermeable films, alginate wound dressings, and electrospun polymer nanofibers. Wound dressings based on polymer nanofibers have received a lot of attention for reasons such as similarity to the extracellular matrix (ECM), the desired cell adhesion, high surface-to-volume ratio, gas exchange capability, nutrient supply, and fluid evaporation control. So far, the use of electrospun polyurethanes for the preparation of wound dressings has been reported in various studies. However, the results of studies on a wide range of wound dressings have shown that almost no polymer alone can heal different wounds, effectively. For this reason, many efforts have been made recently to develop polyurethane wound dressings to heal various types of wounds. In this regard, natural polymers have been used due to properties such as biological activity, biocompatibility, and biodegradability along with polyurethanes with desirable physical and mechanical properties. In this article, after introducing the the mechanism of wound healing and describing the characteristics of an ideal wound dressing, the polyurethane/natural polymer blends nanofibers for use as electrospun wound dressings will be discussed.

Psychological parameters are among the most important components in determining the job performance of employees in the workplace and can be strongly affected by the epidemic of infectious diseases like COVID-19. The aim of this study was to investigate the effect of COVID-19 pandemic on mental workload and Occupational burnout of medical staff in Iran.

This case-control study was performed among the healthcare staff of two hospitals in Tehran province in 2021. All employees working in two hospitals were included by census method. The total number of people studied was 412 personnel. NASA-TLX and Maslach Burnout Inventory questionnaires were used to assess mental workload and burnout, respectively. Data were analyzed using Independent t-test and Chi-square.

The present study results revealed that the mean age, work experience, daily working hours, and body mass index of the studied employees were 36.70 ± 11.48 years, 12.53 ± 7.13 years, 9.64 ± 3.13 hours, and 23.89 ± 4.73 kg/m2, respectively. There was a significant difference between the two groups of cases and controls in the values of mental workload (P = 0.011) and burnout (P = 0.001).

The present study's findings revealed that the prevalence of COVID-19 could increase the values of mental workload parameters and burnout of health care personnel in medical settings. Therefore, control measures and psychological interventions to improve healthcare personnel's mental and physical health during the COVID-19 epidemic are mandatory.

Today, the prevalence of bacterial infections and their resulting human and financial losses has led scientists constantly to seek solutions to develop knowledge in controlling these pathogenic microorganisms. Bacterial adhesion and their growth on different surfaces cause the accumulation of these microorganisms and the formation of biofilms. These developed microcolonies can grow and detach from the surface and spread infections. Therefore, the best way to prevent spreading the infections and diseases is to prevent the formation of biofilms using antimicrobial surfaces. In this regard, one of the most important tools introduced is the use of antibacterial polymer coatings. Polyurethanes have received much attention due to their unique properties such as biocompatibility, the possibility of using various raw materials, and controllable properties. In recent years, waterborne polyurethanes have been extensively studied due to less frequent use of volatile organic compounds (VOCs) in their preparations, easy fabrication, low viscosity, the possibility of spraying, high adhesion to different surfaces, high abrasion resistance, ability to disperse a variety of additives, and rapid film formation in biomedical fields such as antibacterial coatings, wound dressings, and biological products. In this review article, first, the various methods of preparing antibacterial polymer coatings are described. These methods include the use of nanostructures, combined with antibacterial polymers, and the use of antibacterial monomers. As a result, polyurethanes and waterborne polyurethanes have been developed. The following is a review of studies on the preparation of antibacterial waterborne polyurethanes using different strategies such as the addition of nanostructures, blending with antibacterial polymers, drug loading, the use of antibacterial monomers, and polymer surface modification. The products developed during these studies have been proposed for a variety of applications such as medical equipment coating, wound dressings and packaging industry.

The purpose of this study was to design and validate a competency model for the selection and appointment of queue managers (schools) at the level of leadership and management subsystem in the Fundamental Reform Document of Education (FRDE). It is a mixed-method research using an exploratory approach. Sampling in the qualitative section was done purposefully with the technique of a network of experts and 22 people (including: nine drafters of the Fundamental Reform Document, seven experts and executives in the leadership and management subsystem and six members of the faculty of educational management) participated in the interview. Also, in the quantitative part of the statistical population, there were 599,948 school principals in Tehran, of whom 382 people were selected using the Cochran's formula and cluster sampling. A semi-structured interview was used in the qualitative part and a researcher-made questionnaire in the quantitative part. The data obtained from the interviews were thematically analyzed and are studied using the structure-based data theory of Chalmers structural type. Quantitative data were also analyzed by predictive correlation method and by using confirmatory factor analysis using Smart PLS 3 ‌ software. Content validity and face validity methods were used to examine the questionnaire and the results were adjusted in several stages. Findings indicate that in the qualitative part, a total of 80 competencies were identified and assigned as competencies required by school principals, based on the interviews. In the quantitative part, the overall quality of the measurement model was confirmed with a total of 75 indicators. Finally, the approved indicators were defined in the form of 17 subcategories, 6 main categories and finally in two specialized and general dimensions.