نشریه طب کار
سال سیزدهم شماره 3 (پیاپی 44، پاییز 1400)

 Back pain is one of the most important occupational problems among health care workers that have detrimental effects on their personal and professional life. Therefore, this study aimed to investigate the relationship between low back pain and quality of life in prehospital emergency staff and the role of demographic variables in this regard.

 This is a descriptive correlational study. The population was a prehospital emergency staff that entered to study by using the census method at 2020. Data gathering instruments were demographic characteristics, low back pain, and quality of life questionnaires. Data were entered into SPSS 22 and were analyzed using descriptive and analytical statistics.

 The results showed that the related to the low back pain score of emergency medical technicians was 51.34± 4.149, which is high. In addition, the quality of life mean and standard deviation was 30.35± 4.851, which shows a low level. There is a significant relationship between back pain and quality of life (p = 0.001, R = 0.723).

 Low back pain is so common among emergency medical personnel that the issue may affect a person's life and work and creates many problems in terms of personal, family, socially, economically, and professionally, which reduce their quality of life.

A firefighting job is a demanding job that has a high degree of stress due to constant exposure to life-threatening conditions. Therefore, the present study was conducted to investigate the mediating role of intrinsic job motivation in the relationship between job commitment and professional ethics with extra-role performance among firefighters in Isfahan.

The type of study was descriptive and the method was correlation. Statistical population included all firefighters in Isfahan, from which 228 people were selected as a sample through random sampling. The instruments used includedinternal job motivation questionnaires (Gagne et al., 2015), job commitment (Blau, 2009), professional ethics (Hackerina, 2011) and extra-role performance (Lee and Allen, 2002). Data were analyzed by the Pearson correlation coefficient and structural equation modeling (SEM). SPSS23 and Smart PLS3 software were used for data analysis.

The results showed that professional ethics has a direct effect on intrinsic job motivation, extra-role performance toward organization and individual; Intrinsic job motivation has a direct effect on the extra-role performance toward individual; Job commitment has a direct effect on intrinsic job motivation and extra-role performance toward organization (P <0.05). Also, the proposed model has a good fit and by examining the indirect and mediating effects through the bootstrapping method in PLS software, was shown that intrinsic job motivation mediates the effect of job commitment and professional ethics on the extra- role performance toward individual.

The findings of the present study showed that professional ethics and job commitment could increases extra-role behaviors through intrinsic job motivation. Therefore, due to the role and importance of extra-role behaviors in the firefighting profession, attention to this important finding should be considered by managers and policymakers of this organization.

 Nowadays, the cement industry is regarded as one of the most important air pollution industries globally. This study aimed to simulate the emission of NOx, CO, SO2, and PM pollutants caused by the Sabzevar Cement Factory chimney by SCREEN3 software. 

 In this study, the SCREEN3 software was employed for the distribution of NOx, CO, SO2, and PM pollutants. The inputs of the model include the concentration and emission of pollutant gases, physical factors associated with the cement factory chimney, wind speed and direction, ambient temperature, and stability classes. 

 The results of this study indicated that the maximum concentrations of NOx, CO, SO2, and PM by the SCREEN3 software occurred in unstable weather conditions (B) and wind speed of 5 m.s. The highest concentrations of NOx, CO, and PM (use of gas) were at a distance of 1400 meters from the factory chimney with the rates of 0.9, 0.32, 6.2 μg.m³, respectively. Moreover, the highest concentrations of NOx, CO, SO2, and PM (using fuel oil) were predicted at a distance of 1100 m from the factory chimney with 19.5, 360, 9, and 7.9 μg.m³, respectively. A comparison of the obtained results with the standard of the Environmental Protection Agency of Iran (EPA) revealed that the concentrations of NOx, CO, SO2, and PM were not higher than the standards. 

 The comparison of results with EPA standard and Iranian clean air standard showed that NOX, CO, SO2, and PM concentrations were not higher than standards during the sampling period.

The unique properties of nanomaterials, in addition to their applications in science and technology, can be a threat to human health and the environment. Exposure to these materials may occur in workplaces or in research laboratories. It can be said that about half of people with occupational exposure to nanomaterials work in academic environments and laboratories. So, the present study was conducted to design and validate a tool to investigate the principles of working safely with nanomaterials in research laboratories.

The tool was designed using reports, instructions and articles related to " Methods of working safely with nanomaterials". The validity of the tool was assessed using Lawshe method by calculating CVI and CVR. The reliability of the instrument was evaluated using Cronbachchr('39')s alpha coefficient and kappa coefficient.

The tool was designed in 5 sections: "General Information", "Transportation and Storage of Nanomaterials", "Engineering Controls", "Administrative Controls" and "Personal Protection Equipment". After validation, 5 items did not get the necessary points to stay in the tool and were removed. The Cronbachchr('39')s alpha value for each section of the tool was more than 0.80, indicating that the was "appropriate".

According to the results, it seems that the tool studied in this study is compatible for the designed purpose and is ready to be used as a questionnaire or checklist.

 Lead is a toxic heavy metal that has adverse health effects on blood parameters. About 80% of lead produced is used in batteries, especially vehicle batteries. Therefore, the present study aimed to assess the hematological changes, including total and differential white blood cell (WBC) counts in battery workers exposed to lead, and compare with the non-exposed group.

This cross-sectional study was carried out in a battery industry in Semnan city. The study population consisted of 78 battery workers and 78 healthy non-exposed office workers. A hematology cell counter was used to determine the total, and differential WBC counts. Blood lead level was measured in accordance with the NIOSH method 8003.

 Blood lead levels were about two times higher than the TLV recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) for this compound (20 µg/dl). The level of WBC (8.07± 2.55 mm3 blood×103 vs. 7.27 ± 1.58 mm3 blood×103) was significantly higher, while the level of monocyte was significantly lower (6.96 ± 1.72 % vs. 7.67 ± 1.87 %) in the exposed group than in the non-exposed group. After adjustment for potential confounders such as age and work history, a significant association between exposure to lead and WBC and monocyte levels was reported.

 The present study's findings indicated that exposure to lead was associated with total and differential white blood cells changes in the exposed group compared to the non-exposed group.

 In many workplaces today, the incidence of human error can lead to catastrophic accidents in which human error is the main cause of accidents. Due to the vital role of the control room in guiding and controlling various sites of the pipe industry, especially the outer coating sector, the incidence of any error can lead to human accidents, damage to machinery, and interruption in production. This study aimed to identify and evaluate human error by Human Error Calculator (HEC) method in the epoxy control room of a pipe mill company. 

 In the present descriptive cross-sectional study, the HEC method was used to identify and evaluate human errors. The HEC technique is provided by Risk Map Company, in which the probability of human error is based on five factors affecting the occurrence of human error, including a degree of urgency, complexity, importance, degree of individual skill, and task repetition, using a disk-shaped tool called Risk Disk is determined through direct observation, available instructions and interview with the head of the mentioned unit.

 According to the results of this study, out of 11 identified tasks, five job tasks with a risk number of 70% have a high probability of human error, four job tasks with a risk number of 50%, and one job task with a number There is a 40% risk of moderate human error, And a job task with a 20% risk number has an increased chance of human error.

 The results of the present study showed that the HEC method is easy to use and is a simple and useful tool for professionals to calculate the probability of human error. In addition, HEC is a practical, effective and beneficial method for managers to reduce human error.

 Nowadays, counterproductive behaviors have become a common and costly position for many organizations, and Managers of organizations are always looking for a suitable and practical solution to reduce this type of behavior in their organization. Due to the importance of the subject, the present study aims to investigate the imbalance of effort and reward as a predictor of counterproductive behaviors.

 The present study is a cross-sectional study. The target population was all nurses working in hospitals in Hamadan, and according to the simple random sampling method, 320 people were selected as the research sample. The tools used in this study were the Imbalance of Effort-Reward questionnaire and the counterproductive questionnaire. Data analysis was performed using the Pearson correlation method using SPSS18.

 The results showed that the effort-reward imbalance model at a significance level of 0.05 is able to predict individual counterproductive behaviors in nurses (P = 0.036). Among the studied variables, the reward variable is able to predict individual counterproductive behaviors (β = -0.179 and P = 0.006) and organizational (β=-0.171 and P = 0.009) and the over-commitment variable is able to predict individual counterproductive behaviors. (β= 0.145 and P = 0.05). According to the results, the effort-reward imbalance model could not predict organizational counterproductive behaviors.

 Based on the results, it can be concluded that job stress is an important factor in creating Counterproductive behaviors in personnel and the components of the model used in this study can be used to reduce the incidence of these behaviors among nurses.

 A high-risk job, firefighting involves a wide range of tasks. Given the difficult nature of the job with all the responsibilities included, and in addition to the impending physical injuries, firefighters undergo several emergencies which can endanger their psychological health. Therefore, the present study was conducted to investigate the psychological consequences of firefighters' work conditions.

 The research method was qualitative and phenomenological. Using the purposeful sampling method, 16 firefighters were selected from fire stations across the city of Kerman, Iran; saturation criteria were used in the selection of participants. Data were collected using semi-structured interviews and analyzed using Colaizzi’s seven-step method. In this way, first, the interviews were coded, and then based on the similarity of codes, 4 main categories were extracted. 

results showed that persistent stress (caused by the sound of fire alarms and announcement of fire emergencies, trying to make it to the scene on time, worrying about not being on time, and not finding the address of the incidents, complications, and uncertainties of the incidents), sleep problems (these include sleep disturbances, insomnia, difficulty maintaining sleep, startled waking up, somniloquy), negative emotions reminiscent of painful events, and difficulty in establishing good relationships with family members, are the most important psychological consequences that firefighters faced due to their working conditions.

 Considering the important role of firefighters in providing services in emergencies, the psychological consequences of this job are risk factors that harm the health and the performance of firefighters. Therefore, appropriate measures and planning need to be taken to manage and reduce ongoing stress and improve the quality of firefighters' sleep. To manage and reduce negative emotions and their family problems, appropriate training should be provided.