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Identifying the individual factors is a major issue in determining the likelihood of human error and ultimately human reliability. In current human reliability assessment methods, this is determined based on a list of performance shaping factors and experts' judgment. This was a qualitative content analysis study, in which the participants were selected using purposive sampling from combined cycle power plant control rooms. Semi-structured interviews were performed and collected data were analyzed. A total of 32 operators (20 module controllers, eight head operators and four managers) were interviewed. Five categories were extracted, namely 'mental condition', 'consciousness at work', 'professional competence', 'communication skills' and 'quick reactions and decision-making capabilities'. Accordingly, it is suggested to taken into account such factors as professional competence and speed of reactions and to pay more attention to their important factors in the reliability of operators in combined cycle power plant control rooms.

Workload has long been considered as one of the important factors for personal functions and malfunctions, particularly in complex systems. Undertaking operations in workstations of such systems usually entails complex tasks and poor cognitive performance of their operators may contribute to human error and critical subsequent consequences. Although many studies have investigated the effects of workload on the cognitive performance, there is a gap for specific jobs and operations such as control room operation. This paper then aims to determine that what dimensions of the workload has more impact on cognitive performance of a combined cycle power plant (CCPP) Control room operators. Control room operators from two CCPPs participated (n = 95) in this study. Hierarchical task analysis (HTA) was employed to perform the job analysis. To assess the perceived workload, NASA Task Load Index (NASA-TLX) was performed at the end of the work shift. The participants were subjected to three cognitive performance tests including sustained attention, simple reaction and working memory at the beginning and end of the work shift. The values of mental demand on check and control tasks (92.17 ± 4.38), decisions about abnormal conditions (90.16 ± 5.71) and reporting (85.09 ± 3.25) were high. The task of communication and coordination in terms of temporal demand (71.66 ± 7.3) and performance (68.04 ± 4.92) had higher values compared to other tasks. The highest weighted workload (84.27 ± 6.48) was also attributed to the task of checking and controlling. Sustained attention and working memory were more susceptible to excessive workload among CCPP control room operators.

Investigation of past accidents has shown that LPG tank accidents cause significant damage to the industry due to the storage of large volumes of flammable materials in them. This study aimed for developing a predictive accident model for dynamic risk assessment of propane storage tanks of the refinery. Hazards and safety barriers were identified using MIMAH methodology. The basis of MIMAH methodology is Bow-tie method. To construct the Bow-tie diagram, first, accidents that occurred on LPG tanks were extracted from the databases of accidents and valid sources. The top events of the accidents were identified and analyzed by the fault tree. The Bow-tie diagrams were constructed and the barriers on the diagrams were identified and verified by refinery experts. According to the SHIPP model, safety barriers were categorized into seven main barriers. The failure rates of the fault tree basic events were extracted from reliable sources and the prior probability of barriers was calculated. Based on the failure or success of safety barriers, 6 levels of severity of consequences, safe, near miss, mishap, incident, and catastrophic accident were considered. Using the prior probability of failure of the barriers, the probability of occurrence of each level of severity of consequences was calculated with the event tree. In the next step, this paper employed LPG storage tanks past accidents to construct a likelihood function and update prior probability using the Bayesian equation. Finally, the posterior probability of occurrence of the consequences was calculated using the posterior probability of failure of the barriers. Because LPG accidents occur with low probability and high severity, predicting accidents dynamically helps people to always be prepared to prevent their occurrence.

Accidents of liquid pipelines are occurring around the world for various causes and have major consequences. Identification of pipeline accident causes is a primary and basic action for prevention of accidents. Also, survey of consequences can help a management for risk assessment. This study presents a review of liquid pipelines leak, fire and explosion scenarios causes and consequences. The accidents of liquid pipelines were collected from accident databases, papers and other sources. The causes and consequences of the 81 accidents were classified. The most frequent causes of accidents were corrosion with 19%, sabotage with 15% and improper repair and maintenance with 12%. Identification of pipelines accidents causes and consequences can provide insights into how managers make implement effective corrective actions and safety barriers.

BACKGROUND: Exploring experiences of individuals for barriers they confront relating to safety could help to design safety interventions with an emphasis on the most safety influencing factors. OBJECTIVE: This study strived to present an empirical exploration of individuals’ experiences across the petroleum industry at different levels of the organizational structure for factors that influence occupational accidents. METHOD: Based on accidents history, face-to-face semi-structured interviews were conducted with individuals who engaged in fatal activities, as well as authorities responsible for managing safety. The qualitative content analysis of 46 interview transcripts was conducted using MAXQDA software. RESULTS: A three-layer model comprising organizational, supervisory and operator level influencing factors with 16 categories were found influence factors of occupational safety. The results highlighted the role of organizational factors, including inappropriate contract management, inadequate procedures, and issues relating to competency management and the organizational climate. Moreover, defects relating to the monitoring and supervision system were identified as important causes of accidents. CONCLUSIONS: The findings demonstrated that the qualitative approach could reveal additional latent aspects of safety influencing factors, which require consideration for the appropriate management of occupational safety. This study can guide the planning of preventive strategies for occupational accidents in the petroleum industry.

In this study, barriers elements and initiating events of accidents and their risk influence factors were identified and classified according to a developed conceptual model, relationship between the risk influences factors were determined using a fuzzy DEMATEL model, the risk influence factors weight was determined using a fuzzy AHP model and conditional probability table of the risk influence factors was obtained using Roed method. The probability of the initiating events and the barrier elements failure was determined using fuzzy logic. The barrier elements and the initiating events were modeled by mapping bow-tie in Bayesian network. The Bayesian networks of risk influence factors were constructed by mapping the fuzzy DEMATEL outputs in the Bayesian network. Leading indicators were developed for the risk influence factors and their content validity, practicability and importance were assessed using the fuzzy logic and eliciting expert’s opinion using a paired comparison method. Finally, this paper employed atmospheric storage tanks as a case study for explanation and verification of the significant benefits of the methodology developed by this study.

Introduction A vast amount of research has been conducted to identify human and organizational factors that contribute to the occurrence of occupational incidents. Considering the identified factors, the question is how much the occupational incident probability will decrease in the absence of one or more recognized contributory factors. Methods Twenty-one fatal accident reports were selected for Root Cause Analysis (RCA). The contributory factors were identified by content analysis of the accident scenarios. A 5-point Likert questionnaire was developed to measure the probability of identified factors. Using the identified contributory factors and their corresponding probabilities, a Bayesian network model was constructed for estimating the probability of the occupational incident in the absence of each contributory factor. Results Procedure violation, poor risk perception, and poor management commitment were three top-ranking contributory factors. The Bayesian network estimated that preventing procedures violation could cause a reduction of 44 % in the occupational incident probability. Conclusion Using Bayesian network’s advantages is an effective technique for quantifying occupational safety risks. Ranking the contributory factors enables us to choose the most effective prevention strategies. Procedure violation (a type of unsafe act) was the most influencing factor in occupational incident probability.

Background: The oil and gas industry is one of the riskiest industries for confined space injuries. This study aimed to understand an overall picture of the causal factors of confined space accidents through analyzing accident reports and the use of a qualitative approach. Methods: Twenty-one fatal occupational accidents were analyzed according to the Human Factors Analysis and Classification System approach. Furthermore, thirty-three semistructured interviews were conducted with employees in different roles to capture their experiences regarding the contributory factors. The content analyses of the interview transcripts were conducted using MAXQDA software. Results: Based on accident reports, the largest proportions of causal factors (77%) were attributed to the organizational and supervisory levels, with the predominant influence of the organizational process. We identified 25 contributory factors in confined space accidents that were causal factors outside of the original Human Factors Analysis and Classification System framework. Therefore, modifications were made to deal with factors outside the organization and newly explored causal factors at the organizational level. External Influences as the fifth level considered contributory factors beyond the organization including Laws, Regulations and Standards, Government Policies, Political Influences, and Economic Status categories. Moreover, Contracting/Contract Management and Emergency Management were two extra categories identified at the organizational level. Conclusions: Preventing confined space accidents requires addressing issues from the organizational to operator level and external influences beyond the organization. The recommended modifications provide a basis for accident investigation and risk analysis, which may be applicable across a broad range of industries and accident types. Keywords: Accidents, Confined space, Content analysis, HFACS, Semistructured interview

Cigarette smoking is a possible risk factor for hearing loss. However, the impact of simultaneous exposure to noise and smoke on hearing has remained controversial. This study investigated the combined effect of exposure to cigarette smoking and noise on hearing loss. Three groups of male Wistar rats (275 ± 25 g) were subjected to white noise (102 ± 0.5 dB), cigarette smoking (20 cigarettes), and both cigarette smoking and noise for 8 h and 10 days inside the exposure chamber. The control group was exposed to neither noise nor smoke. Distortion product otoacoustic emissions (DPOAE) were measured before any intervention, and it was repeated 1, 7, and 21 days after the last exposure. One-day postexposure to noise, cigarette smoking, and both cigarette smoking and noise, the mean of DPOAE amplitudes decreased significantly ( p < 0.05) between, respectively, 5.7–30.7, 1.5–7.5, and 5.2–32.6 dB within the frequency range of 4620–9960. Temporal DPOAE change in rats exposed to noise or both cigarette smoking and noise was not significantly different ( p > 0.05). DPOAE amplitudes returned to the baseline values in the group subjected to smoking 21 days postexposure. The most permanent change was observed in rats exposed to both cigarette smoking and noise. Accordingly, simultaneous subacute exposure to noise and cigarette smoking increases the effect of noise on permanent hearing loss. Therefore, smoking workers exposed to noise might be at a greater risk of developing hearing loss, and it is recommended that authorities in charge take note of this evidence.

In this study, the Fire Dynamics Simulator (FDS) is adopted to simulate tank and dike pool fires in a tank farm. These simulations are performed in order to evaluate the potential for secondary fire events in nearby storage tanks based on the resulting incident radiative heat flux. As a precursor to the tank farm fire scenario case studies, the model is compared with experimental data of 1 m crude oil pool fire and 30 m and 50 m diameter kerosene pool fires. These comparisons are made to validate the modeling approach ahead of the application of the modeling to a problem of practical interest. The results of the FDS are consistent with experimental data. The FDS results indicate that the studied dike pool fire has the potential of triggering the domino effects in the tank farm, but not so true in the case of the tank fire. Quantitative results obtained by FDS modeling can be used in quantitative risk assessment of a tank farm and determination of safe inter-tank separation distances.

Background Construction workers are at a high risk of exposure to various types of hazardous substances such as crystalline silica. Though multiple studies indicate the evidence regarding the effectiveness of different silica exposure reduction interventions in the construction sector, the decisions for selecting a specific silica exposure reduction intervention are best informed by an economic evaluation. Economic evaluation of interventions is subjected to uncertainties in practice, mostly due to the lack of precise data on important variables. In this study, we aim to identify the most cost-beneficial silica exposure reduction intervention for the construction sector under uncertain situations. Methods We apply a probabilistic modeling approach that covers a large number of variables relevant to the cost of lung cancer, as well as the costs of silica exposure reduction interventions. To estimate the societal lifetime cost of lung cancer, we use an incidence cost approach. To estimate the net benefit of each intervention, we compare the expected cost of lung cancer cases averted, with expected cost of implementation of the intervention in one calendar year. Sensitivity analysis is used to quantify how different variables affect interventions net benefit. Results A positive net benefit is expected for all considered interventions. The highest number of lung cancer cases are averted by combined use of wet method, local exhaust ventilation and personal protective equipment, about 107 cases, with expected net benefit of $45.9 million. Results also suggest that the level of exposure is an important determinant for the selection of the most cost-beneficial intervention. Conclusions This study provides important insights for decision makers about silica exposure reduction interventions in the construction sector. It also provides an overview of the potential advantages of using probabilistic modeling approach to undertake economic evaluations, particularly when researchers are confronted with a large number of uncertain variables.

Solar ultraviolet (UV) radiation is the second most prevalent carcinogenic exposure in Canada and is similarly important in other countries with large Caucasian populations. The objective of this article was to estimate the economic burden associated with newly diagnosed non-melanoma skin cancers (NMSCs) attributable to occupational solar radiation exposure. Key cost categories considered were direct costs (healthcare costs, out-of-pocket costs (OOPCs), and informal caregiver costs); indirect costs (productivity/output costs and home production costs); and intangible costs (monetary value of the loss of health-related quality of life (HRQoL)). To generate the burden estimates, we used secondary data from multiple sources applied to computational methods developed from an extensive review of the literature. An estimated 2,846 (5.3%) of the 53,696 newly diagnosed cases of basal cell carcinoma (BCC) and 1,710 (9.2%) of the 18,549 newly diagnosed cases of squamous cell carcinoma (SCC) in 2011 in Canada were attributable to occupational solar radiation exposure. The combined total for direct and indirect costs of occupational NMSC cases is $28.9 million ($15.9 million for BCC and $13.0 million for SCC), and for intangible costs is $5.7 million ($0.6 million for BCC and $5.1 million for SCC). On a per-case basis, the total costs are $5,670 for BCC and $10,555 for SCC. The higher per-case cost for SCC is largely a result of a lower survival rate, and hence higher indirect and intangible costs. Our estimates can be used to raise awareness of occupational solar UV exposure as an important causal factor in NMSCs and can highlight the importance of occupational BCC and SCC among other occupational cancers.

Background Noise exposure causes loss of cochlea hair cells, leading to permanent sensorineural hearing loss, and initiates pathological changes to the bipolar primary auditory neurons (ANs). This study focuses on the effects of N-acetyl-l-cysteine (NAC) in protecting the density of spiral ganglion cells and in histological changes induced by continuous noise exposure in rats. Methods Twenty-four male Wistar rats were randomly allocated into four experimental groups to receive NAC, saline, noise, or both noise and NAC. Noise exposure continued for ten days. Saline and NAC were injected daily during the noise exposure, and 2 days before and after the noise exposure. Evaluation of cochlear histopathology and the density of spiral ganglion cells was performed 21 days after exposure. Results In the animals exposed to noise, a reduction in the density of spiral ganglion cells was evident in both the basal and middle turns of the cochlea. This improved on receiving NAC treatment (P = 0.046). In the histopathology evaluation, some histological changes, such as disorganised architecture of the outer hair and supporting cells and a slightly thickened basilar membrane, were found in the basal turns in the noise group. Conclusion NAC offered partial protection against noise exposure by improving the density of spiral ganglion cells and reducing morphological changes.

We estimate the potential cost-benefit of a caregiver-friendly workplace policies (CFWPs) educational intervention to facilitate uptake of supports for carer-employees (CEs) at a post-secondary institution.We identified CEs through a voluntary survey and estimated the economic burden of caregiving activities from the CEs' and employer's perspective. The latter is used as the baseline of comparison for evaluating the cost-benefit of the intervention.The economic cost of caregiving-related activities for the "no intervention" scenario was estimated at $33,841,789 ($32,922 per-case) and $8,916,342 ($8,674 per-case) from the CEs' and employer's perspectives, respectively. We find the educational intervention is a cost-beneficial program with the net benefit ranging from $48,010 to $676,657, based on six scenarios of effectiveness.This study provides practical information for human resources and operations management decision-making in terms of a CFWPs educational intervention.

Construction is a major source of employment in many countries. In construction, workers perform a great diversity of activities, each one with a specific associated risk. The aim of this paper is to identify workers who are at risk of accidents with severe consequences and classify these workers to determine appropriate control measures.We defined 48 groups of workers and used the Bayesian theorem to estimate posterior probabilities about the severity of accidents at the level of individuals in construction sector. First, the posterior probabilities of injuries based on four variables were provided. Then the probabilities of injury for 48 groups of workers were determined.With regard to marginal frequency of injury, slight injury (0.856), fatal injury (0.086) and severe injury (0.058) had the highest probability of occurrence. It was observed that workers with1 year's work experience (0.168) had the highest probability of injury occurrence. The first group of workers, who were extensively exposed to risk of severe and fatal accidents, involved workers ≥ 50 years old, married, with 1-5 years' work experience, who had no past accident experience.The findings provide a direction for more effective safety strategies and occupational accident prevention and emergency programmes.

Background. Accident analysis is the main aspect of accident investigation. It includes the method of connecting different causes in a procedural way. Therefore, it is important to use valid and re...

The present study was designed to investigate the simultaneous effects of physical, psychosocial and other work-related risk factors on the work ability index (WAI) score among industrial workers.This study used a cross-sectional design with a questionnaire survey. A total of 280 workers were included in the study. Data were collected using three questionnaires including the Persian version of the WAI, the Persian version of the job content questionnaire and an author-developed measure (to assess work-related factors, health-related factors and socio-demographic characteristics).The majority of the participants were young, but they had poor WAI scores (mean 37.3 ± 6.4) and 44.3% of them had poor or moderate work ability. Occupational accidents and injuries were found to be the strongest predictors of WAI scores. Additionally, there was a strong association between WAI scores and supervisor support, skill discretion, occupational training, sleep quality, work nature and educational level.Intervention programs should focus on improving supervisor support, sleep quality, job skills and knowledge and on decreasing physical and mental work demands. Additionally, implementing a comprehensive occupational health and ergonomics program for controlling and reducing hazardous working environments and occupational injury rates should be considered.

Background: The most accidents can be directly attributed to human factors. Hence, more traffic crashes result from driver malfunctioning which from among them, the driver behavior is a proximal factor in the road traffic injuries causation chain. Objectives: This study aims to investigate relationship between aberrant driving behaviors questionnaire (DBQ factors) and self-report crashes involvement amongst professional bus drivers of public transportation system. Materials and Methods: This analytical descriptive study was performed on 161 urban bus drivers in Tehran. Proportional sampling method was used to select drivers from nine systems or areas. Data were collected through questionnaire including driver's behavior and their demographic information. Validity and reliability of the driver's behavior questionnaire for bus drivers had been confirmed in a previous study. Data collection was analyzed by Pearson correlation and regression logistic of in SPSS 16 of software. Results: Drivers reported accident involvement during the past three years with mean and standard deviation 2.4 ± 3.2, so that 31.1% had been involved in three or more accidents. There was a negative significant correlation between age and risky violation (P = 0.01). Furthermore, accidents involvement in the last three years was positively correlated with working hours per week (P = 0.003) and traffic offences (P = 0.005). Mistake as a driving aberrant behavior had a direct significant relationship with annual mileage (P = 0.020) and accidents involvement in last three years (P = 0.025). Conclusions: Bus driver’s crashes can be reduced by less driving time and mistakes which is dependent on mileage they drive.

Background: Patient safety is one of the major issues which are concerned with the World Health Organization (WHO) and the medical community in developing and developed countries. Based on Studies, about 10 % of patients admitted in hospitals will be damaged. Objectives: The aim of this study was to evaluate patient safety climate among nurses and their roles for predicting medical errors. Patients and Method: Questionnaire responses were obtained from 122 nurses. The questionnaire comprised four parts included 20 items related to patient safety climate, 6 items to Organizational factors, 15 items to influential factors on the incidence of medical errors and overall level of patient safety. The relationship between patient safety climate and factors in medical errors was evaluated by regression analysis using SPSS 17 software. Results: According to the results, there was a negative relationship between patient safety climate and factors affecting the incidence of medical errors (β = -0.22, P < 0.05). Also, poor safety climate was established among nurses (average of less than 3.5). Conclusions: As the nurses play direct roles associated with family members and healthcare professionals for providing safe and quality, therefore full attention to the safety climate is recommended for reducing medical errors and improving patient safety. The quality of Interactions among therapeutic members and assessing patient conditions and full dominance on treatment process will be extremely effective in health care.

Background: There is currently great concern about the possible adverse effect of microwave radiation from cell phones. In addition, noise is one of the physical pollutants of modern societies. Objectives: The present study aimed to examine the separate and simultaneous effects of cell phone microwaves, noise, and their effects on sperm parameters and total antioxidant capacity in adult male rats. Material and Methods: An experimental study was conducted on 28 Wistar adult male rats (200 - 250 g). Randomly selected animals were divided into four groups; control (C), microwave (M), noise (N), and noise plus microwave (NM) groups. In all groups, a sperm analysis was performed based on World Health Organization (WHO) standards and the mean of the sperms’ total antioxidant capacity was determined by a Ferric Reducing Ability of Plasma (FRAP) assay. The data were analyzed by a one way ANOVA statistical technique, followed by a Tukey’s test using SPSS (version 16) software and P < 0.05 was considered significant. Results: The findings of the study demonstrated that sperm viability and motility, in the exposure to cell phone waves group (group 2) and the simultaneous exposure to cell phone waves and noise group (group 4), decreased significantly compared to the control group (P < 0.05). Moreover, the total antioxidant capacity of sperm in all exposure groups decreased significantly compared to the control group (P < 0.05). Conclusion: Exposure to cell phone waves can decrease sperm viability and motility in adult male rats. These waves can also lower rat sperms’ total antioxidant capacity which results in oxidative stress. Exposure to severe noise levels can cause a significant decrease in the total antioxidant capacity of sperm in adult male rats, resulting in oxidative stress.

The present study aimed to assess the effect of supplementation of omega-3 and/or vitamin C on serum interleukin-6 and high sensitivity C-reactive protein concentration and depression scores among shift workers in Shahid Tondgoyan oil refinery. The study design was randomized, double-blind, placebo-controlled, parallel trial. Totally 136 shift workers with a depression score ≥10 in 21-item Beck Depression Rating Scale were randomly assigned to receive omega-3 (180 mg eicosapentaenoate acid and 120 mg docosahexaenoic acid) or/and vitamin C 250 mg or placebo twice daily (with the same taste and shape as omega-3 and vitamin C) for 60 days in four groups. Depression score, interleukin-6 and high sensitivity C-reactive protein were measured at baseline and after 60 days. This study showed that supplementation of omega-3 plus vitamin C is associated with a decrease in depression score (p

Shift work is associated with sleep deprivation, occupational stress, and increased risk of depression. Depressed patients show increased oxidative stress. During excessive oxidative stress, Malondialdehyde (MDA) increases and total antioxidant capacity (TAC) decreases in body. This cross-sectional study was conducted to determine the serum level of TAC and MDA among depressed rotational shift workers in Shahid Tondooyan Tehran Oil Refinery. 21-item Beck Depression Inventory was used to measure depression level. The level of TAC and MDA was measured by 8 mL fasting blood sample. MDA was determined by thiobarbituric acid reaction. Serum total antioxidants were measured using the ABTS. Results of this study showed that TAC mean and standard deviation concentration was 2.451 (±0.536) mg/dL and MDA was 3.725 (±1.098) mic·mol/L, and mean and standard deviation of depression score and BMI were 14.07 (±3.84) and 24.92 (±3.65) kg/m2, respectively. Depression score had a positive correlation with rotational shift work experience and work experience (r=0.218andr=0.212), respectively, (P<0.05).

Background: Depression and sleep disorders are more prevalent among rotational shift workers than regular day workers. People with sleep disorders have higher inflammatory and pre-inflammatory cytokines than those in the control group. Objectives: The present study was conducted to investigate serum level of high sensitivity C-reactive protein (hsCRP), Interleukin-6 (IL-6) and cortisol among depressed rotational shift workers at Iran petroleum industry. Materials and Methods: In this cross sectional study, 136 shift workers were studied based on the inclusion and exclusion criteria. Demographic information was collected using a self-administered general questionnaire and depression score was gathered according to 21-question Beck depression inventory. Also, weight and height were measured to calculate body mass index and history of disease was collected based on their occupation profile at health center of Tehran Shahid Tondgoyan oil refinery. Results: Mean and standard deviation of serum concentration of hsCRP, IL-6 and cortisol were 1.03 ± 1.56, 1.24 ± 1.24 and 13.12 ± 3.93 respectively; while mean and standard deviation of depression score and BMI were 14.07 ± 3.84 and 24.92 ± 3.65, respectively. Depression score had a positive correlation with rotational shift work experience and work experience (r = 0.218 and r = 0.212, respectively, P < 0.05). An inverse relation was found between serum concentrations of cortisol and age, work experience and BMI (r = -0.236 and P < 0.05, r = -0.174 and P < 0.05, r = -0.288 and P < 0.05, respectively). IL-6 and hsCRP had a positive relation with each other (r = 0.616, P < 0.001). Serum concentration of hsCRP had a positive correlation with BMI (r = 0.241, P < 0.01). Conclusions: There was no significant correlation between depression score and inflammatory markers among depressed shift workers. However, depression score had a significant correlation with shift work experience.

Background: The high item numbers is one of the Work Ability Index (WAI) limitations that make it difficult to be completed by the workers. Using the single-item Work Ability Score (WAS) as a simple is one of the proposed solutions which is valid and suitable measure for work ability. Objectives: The present study aimed to assess work ability using WAI and WAS instruments and to compare their results among Iranian workers. Methods: This cross-sectional study was done on 1579 workers from eleven different work sectors located in different geographical areas in Iran. Work ability was measured by the full Persian version of WAI. Data were analyzed using univariate tests, Pearson product moment correlation, Gamma test, and multiple liner regression analysis. Results: The mean scores of the WAI and WAS were 39.95 ± 6.1 (range 15 - 49) and 8.1 ± 1.8 (range 0 - 10), respectively. Both the WAI and WAS showed the similar patterns of associations with the assessed independent variable. There was a strong correlation between the mean scores of WAI and WAS. In addition, the Gamma test showed that the categories of WAI were strongly correlated with the categories of WAS. Conclusions: The WAS could be used for reliable assessment of work ability among Iranian workers. To improve the worker’s work ability, interventional programs should focus on the alteration and correction of work schedule, and increasing the supervisor’s support for the young workers.

Background: Previous studies demonstrated partial attenuation of noise induced hearing loss (NIHL) by N-acetyl-L-cysteine (NAC) or CoQ10 (ubiquinone). Objectives: The present study investigates the protection effect of coadministration of NAC and CoQ10 against NIHL. Methods: In an experimental study in Iran in 2015, a total of 36 male Wistar rats (275 ± 25 g) were divided randomly based on the permuted block design into 6 experimental groups: (I) noise controls, (II) noise and NAC, (III) noise and CoQ10, (IV) noise and CoQ10 and NAC, (V) noise and saline (as vehicle of NAC) and (VI) noise and olive oil (as vehicle of CoQ10). Antioxidants and vehicles were intraperitoneally injected once a day for two days prior to and 1 hour before 102 ± 0.5 dB white noise exposure 8 h/day in 10 executive days and two days after the noise exposure daily. Distortion product otoacoustic emissions were measured one day before and 1, 7 and 21 days after the exposure. Results: The temporary hearing changes that occurred 1-day post exposure were not significantly different in all groups (P > 0.05). The total recovery (between 1 - 21 days after noise exposure) varied by a frequency increase between 1.08 - 19.10 in the noise group compared to 1.75 - 24.5 and 0.62 - 22.08 in animals treated with NAC and the combination of NAC and CoQ10 respectively. The less permanent hearing impairment was observed in noise exposed animals treated with either NAC or both NAC and CoQ10. Conclusions: The effect of coadministration of NAC and CoQ10 was neither additive nor synergic in protecting against NIHL.

Background: Different types of direct and passive smoking have been reported to be associated with conductive and sensorineural hearing loss. In this study, we aimed to investigate the relationship between cigarette smoke exposure and cochlear dysfunction. Methods: In this experimental study, 12 male Wistar rats were divided into 2 groups: control group without exposure and smoke-exposed group housed in a whole-body exposure chamber (exposed to the smoke of 20 cigarettes; 9 ± 1 mg of tar and 0.8 ± 0.1 mg of nicotine per cigarette) for 8 hours a day during 10 consecutive days. The main and side stream smoke was generated in accordance with the federal trade commission (FTC) regimen (2-second puff with 35 mL volume and frequency of 1 puff per minute). Distortion-product otoacoustic emissions (DPOAEs) were evaluated at a frequency range of 4620 - 9960 Hz at baseline and 1, 7, and 21 days after exposure. Repeated measures ANOVA and t test were performed for data analysis, using SPSS version 18. Results: In the smoke-exposed animals, temporary hearing changes were significantly different from the baseline at a greater attenuation and higher frequencies (P 0.05). Conclusions: Subacute smoke exposure for 10 days resulted in the temporary reduction of DPOAEs. Chronic and subchronic effects of smoke on permanent hearing damage need to be investigated through further animal studies.

Abstract. Background: This study assessed the effect of supplementation of omega-3 fatty acids and ascorbic acid alone and in combination on the level of lipid peroxidation (malondialdehyde, MDA concentration), total antioxidant capacity (TAC) and depression scores in depressed rotational shift workers in the Tehran Shahid Tondgoyan Oil refinery. Material and methods: In this randomized, double-blind, placebo-controlled trial, 136 men who met the inclusion and exclusion criteria and had a Beck Depression Inventory (BDI) score ≥ 10 were selected. Among the participants, 33 received omega-3 fatty acid soft gel (1000 mg twice daily) with vitamin C (250 mg twice daily) (group 1), 31 took omega-3 fatty acid supplements and vitamin C placebo (group 2), 30 took omega-3 fatty acid supplement placebo and vitamin C (group 3), and 32 received omega-3 fatty acid supplement placebo and vitamin C placebo (group 4) for 2 months. Measured were serum MDA, TAC concentrations, and BDI scores at baseline and after 2 months. Results: This study showed that the BDI score was reduced significantly in all 4 groups, however, the level of decrease was more in the omega-3 fatty acid (alone) supplementation group (mean 6.29 score decrease) (p < 0.001). MDA level decreased significantly in groups with omega-3 fatty acids (mean 0.78 μmol/L ± 1.64 μmol/L decrease) (p = 0.014) or vitamin C supplementation alone (mean 0.74 μmol/L ± 1.55 μmol/L decrease) (p = 0.014), but not in combination. Conclusions: Supplementation of omega-3 fatty acids alone and not in combination with vitamin C had a better impact on depression and MDA level pronounced in depressed male shift workers.

Background: X-band microwaves, which are part of electromagnetic waves, have various applications, such as satellite communications, radar, navigation, air traffic control, marine functions, and weather stations. Therefore, many workers are exposed to these waves in the workplace. Previous studies showed that these frequencies have adverse health effects. In occupational health, the use of shielding as an engineering measure is a priority in controlling radiation in the workplace. Objectives: This study investigated the efficacy of net epoxy resin as electromagnetic shielding from occupational radiation. Materials and Methods: Epoxy plates were fabricated in three different thicknesses (2, 4, and 6 mm), and their shielding effectiveness was measured by a vector network analyzer. The amounts of reflected energy and transmitted energy were determined by using the scattering parameters. Results: The results showed that the epoxy plates 6 and 2 mm thick had the highest and the lowest averages of shielding effectiveness at 4.48 dB and 1.90 dB, respectively. However, increasing the thickness was useful up to 4 mm. In addition, in a similar attenuation pattern, X-band frequency was divided into lower, middle, and upper sections. The lower section had the highest shielding effectiveness. Conclusions: The results showed that reflection was the main mechanism in the overall shielding effectiveness. These findings indicate that epoxy resin could be applied as a proper shield against microwave radiation in the workplace.

Background: Widespread use of X-band frequency (a part of the super high frequency microwave) in the various workplaces would contribute to occupational exposure with potential of adverse health effects. According to limited study on microwave shielding for the workplace, this study tried to prepare a new microwave shielding for this purpose. Methods: We used EI-403 epoxy thermosetting resin as a matrix and nickel oxide nanoparticle with the diameter of 15-35 nm as filler. The Epoxy/ Nickel oxide composites with 5, 7, 9 and 11 wt% were made in three different thicknesses (2, 4 and 6 mm). According to transmission / reflection method, shielding effectiveness (SE) in the X-band frequency range (8-12.5 GHz) was measured by scattering parameters directly given by the 2-port Vector Network Analyzer. The fabricated composites characterized by X-ray Diffraction and Field Emission Scanning Electron Microscope. Results: The best average of shielding effectiveness in each thickness of fabricated composites obtained by 11%-2 mm, 7%-4 mm and 7%-6 mm composites with SE values of 46.80%, 66.72% and 64.52%, respectively. In addition, the 11%-6 mm, 5%-6 mm and 11%-4 mm-fabricated composites were able to attenuate extremely the incident microwave energy at 8.01, 8.51 and 8.53 GHz by SE of 84.14%, 83.57 and 81.30%, respectively. Conclusions: The 7%-4mm composite could be introduced as a suitable alternative microwave shield in radiation protection topics in order to its proper SE and other preferable properties such as low cost and weight, resistance to corrosion etc. It is necessary to develop and investigate the efficacy of the fabricated composites in the fields by future studies.

Synthesized magnesium/copper (Mg/Cu) bimetallic particles have shown good potential for use in the reduction of nitrate from aqueous solutions. This study was conducted to investigate the main factors affecting the kinetics of nitrate reduction by Mg/Cu particles (100 microm) in uncontrolled reaction conditions. The Mg/Cu bimetallic particles removed the majority of the various nitrate concentrations tested (50, 100, 150, 200 and 300 mg L(-1)) within a short period. The time required for the removal of 90.6% of the NO3(-) from a 100 mg L(-1) solution was about 20 min using 2 gL(-1) bimetallic Mg/Cu at an initial solution pH of 6. The activation energy (Ea) for nitrate reduction by Mg/Cu over the temperature range of 5 to 60 degrees C was 14.21 kJ mol(-1). The experimental results of the kinetic analysis from batch studies indicated that a higher initial nitrate concentration yielded a greater reaction-rate constant and the denitrification rate increased with increase Mg/Cu dosage.