Journal of Health and Safety at Work

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Introduction: Heat stress is one of the Hazardous physical agents in the workplace, which can cause impairment of cognitive performance. The current study aimed to evaluate the effect of different levels of heat stress on attention and reaction time in a laboratory condition.

Material and Method: This experimental study was done among 33 students included 17 males and 16 females. Mean age of the participants was 22.1(SD=2.3). Attention and reaction time parameters were evaluated using the continuous performance test and  reaction time measurement device respectivlely, after exposure to different heat levels (22°C and 37°C). Data were analyzed using ANOVA test and SPSS 20 software.  

Result: The results of tests attention and reaction time showed that the average of attention percentage was decreased and the average of reaction time increased by increasing the heat level, with a  statistical differences of  (P˂0.001) in both cases. Attention percent in terms of exposure to 22°C temperature was significantly higher than 37°C (P˂0.001). But, reaction time was significantly higher than with the exposure to 37°C temperature than 22°C (P˂0.001).

Conclusion: The results of this study showed that, heat by increasing reaction time and decreasing attention leading to an impairment  in the individual’s cognitive performances. Therefore, in jobs such as control rooms and various industries that need attention, concentration and quick reaction, it is necessary to consider and optimize the heat conditions in order to increase the level of attention and decrease of reaction time.

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Introduction: Application of inherently safety principle in the early phase of the design process is very efficient, as this approach is an economic and high efficiency method. While a complete information is not available in the initial phases of the process, the use of valid index to evaluate inherently safety can be efficient. In this case, the best route to design safer process can be selected by comparing the quantitative results.

Material and Method: The comprehensive index to evaluate the inherently safety design (ISD) and cost evaluation of the implementing inherently safety design (ISDC) were studied using a three-step hierarchical matrix screening in this research. Utilizing the proposed inherently safety index, Acetic acid production process and cost resulting from ISD were evaluated. Dimensions of the Matrix for ISD and ISDC included: 1) quadrature inherently safety design vector, 2) location vector of inherently safety design and 3) quantity parameter vector of inherently safety design.

Result: In order to optimize the implementation of inherently safety design and its cost, three hypotheses were used. From them, the idea of using two processes with half capacity and also using 50% Methanol were selected as a design with the highest level of inherently safety and a design with the lowest-cost process, respectively.

Conclusion: In these evalustions the total score for the assumptions of the inherently safety index 1, 2 and 3, were 55,70 and 135, respectively. And the total cost assumptions 1, 2 and 3, have been estimated 858,000, 746,000 and 803,000 US dollars, respectively. Therefore, this tool could show the impact of various scenarios in inherently safety design and also the contrast between the four principles of ISD and its impact on safety and cost factors can be analyzed using an alternative system supplier of methanol.

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Introduction: Electrospun nanofibers are suitable option to synthesize filtering mats for nanoparticles. This study was aimed to fabricate polyurethane nanofiber mats through electrospinning process and to investigate the effect of different parameters such as packing density, face velocity and particle type on the filtration efficiency and quality factor of electrospun polyurethane nanofiber mats.
 

Material and Method: The nanofiber mats were produced by electrospinning  process. Polyurethane granules were dissolved (15w/w%) in a solvent system consisting of dimethylformamide and tetrahydrofuran (3:2). Then, the filtration performance testing system was made at the Fluid Mechanics Department of Hanyang University of South Korea and the filtration efficiency and pressure drop of prepared nanofiber mats were studied.
 

Result: Findings showed that by increasing the duration of electrospinning, the basis weight, thickness, packing density, initial pressure drop and filtration efficiency of the mats increased, and the quality factor of the mats decreased due to the increase of the pressure drop. The increase in electrospinning duration from 15 to 45 minutes was led to the increase in pressure drop from 7 to 32 Pa and the average filtration efficiency was increased about 9-10% for KCl and DEHS test particles. The filtration efficiency and quality factor of the prepared polyurethane nanofiber mats were declined with the increase of filtration face velocity from 2 to 5 and 10 cm/s. The reduction in filtration efficiency was more obvious for particles smaller than 425 nm.
 

Conclusion: The results demonstrated that prepared polyurethan naofiber mats provide acceptable filtration performance. What is more, such nanofiber mats can have other potential benefits such as light basis weight, low thickness and simple production.

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Introduction. The effect of exercise program on the prevention of upper extremities musculoskeletal disorders has attracted the attention of researchers. On the other hand, in assembly workers, the risk of these disorders increases because the part of the body is used successively and without rest. The current study investigates the effect of 8 weeks of Kinesio Taping and sport program on grip endurance in female assembly workers of an electrical piece industrial manufacturer.
Materials and Methods. The current study was used a descriptive-analytic, cross-sectional method among 40 female assembly workers. Participants are exercised and used Kinesio taping for two times per week at eight weeks. The endurance of the grip was determined before and after the intervention by a dynamometer and the maximum time (in seconds) that one was able to continue one third of the maximum voluntary contraction. The DASH questionnaire was used to assess upper limb extremities’ disability. Data were analyzed using SPSS Ver.20 and the P value was considered smaller than 0.05.
Results. In the present study, the mean of right and left hand grip endurance in kinesio type and exercise group before intervention were obtained 10.55 and 9.51, whereas, related results after intervention were obtained 20.55 and 16.18, respectively. Also the score of upper limb disability in kinesio type and exercise group before intervention were obtained 10.55 and 9.51 and after intervention obtained 20.55 and 16.18, respectively(P <0.05).
Conclusion. According to the results, sport exercise and kinesio taping, lead to the increase in the grip endurance time and decrease in the upper limb disability.

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Introduction: Climate change and hot processes in the workplaces has led to an increase in the effects of heat stress on employed people, which has become a major concern, especially in tropical and subtropical countries. Early detection of biomarkers in induction of heat stress-related DNA damage can be used in the identification and evaluation of health and safety, including occupational health professionals, as well as to prevent serious diseases caused by heat stress in various occupations with the nature of hot processes or to help different warm seasons of the year. Therefore, this review study was conducted to identify diagnostic biomarkers heat stress induced- DNA damage in occupational exposure.
Material and Methods: Databases such as PubMed, Scopus, Google Scholar, and Web of Science were systematically searched to meet the study’s goals. Moreover, references to relevant publications were examined. Finally, suitable articles were selected and analyzed using the inclusion (studies on different occupations, different biomarkers in hot work environments, all articles published without time limit until the end of April 2022 , and English and Persian language)  and exclusion criteria.
Results: The results of search in databases showed that 9234 articles were found in the initial search. After removing duplicate and unrelated articles, 2209 eligible articles were selected. Based on abstract full-text screening, 7166 studies were excluded, and based on abstract full-text screening, 21 studies were not accessible. Finally, seven articles were selected to be reviewed. The evidence showed that diagnostic biomarkers included the measurement of 8-hydroxy-2-deoxyguanosine (8-OHdG), micronuclei semen quality, heat shock proteins (HSP70), and leukocytes were extracted to heat stress induced- DNA damage in occupational exposure.
Conclusion: Based on a review of studies,  biomarkers identified are suitable for heat stress induced- DNA damage as a result of occupational exposure to extremely high heat climate conditions. Understanding and identifying appropriate biomarkers in inducing DNA damage can help health and safety professionals determine the amount and magnitude of heat stress responses in occupational exposure to different temperatures and take appropriate measures and interventions to control and reduce the hazard effects of thermal stress. This study can also be considered as a preliminary study for research in the future.

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Introduction: With the spread of the COVID-19 pandemic and the lack of adequate protection by existing protective equipment, many researchers’ attention has turned to developing improved respiratory protection equipment. Considering their special properties and nanoscale dimensions, electrospun nanofibers are a suitable option for improving operational characteristics of substrates used in conventional facemasks. This study aimed to optimize the electrospinning process of polyacrylonitrile nanofibers (PAN) containing ZIF8 and use the optimized substrate in medical facemasks to increase their protective performance.
Material and Methods: This study employed an environmentally friendly method to synthesize ZIF8 in an aqueous environment. Then, PAN/ZIF8 polymer solutions were prepared in dimethylformamide. The effects of electrospinning parameters, including electrospinning voltage, polymer solution concentration, electrospinning distance, and polymer injection flow rate on diameter and uniformity of nanofibers were investigated. Electrospinning conditions were optimized using response surface methodology (RSM) and central composite design (CCD) to obtain desired values for response (dependent) variables. Finally, optimized PAN/ZIF8 and PAN nanofibers were electrospun on spun-bond substrate. Base weight, average diameter of fibers, filtration performance, pressure drop, and quality factor of fabricated substrates were assessed.
Results: According to results, optimal conditions for electrospinning of PAN/ZIF8 polymeric solution for polymer concentration (A), electrospinning voltage (B), electrospinning distance (C), and polymer injection flow rate (D) were respectively 70 w/v%, 20 kV, 18 cm, and 0.4 ml/h. Moreover, despite lower base weight of PAN/ZIF8 nanofiber mask, it displayed higher filtration performance (98.51%), lower pressure drop (31.42 Pa), and higher quality factor (0.140 Pa-1) in comparison to other studied masks.
Conclusion: Experimental models developed in this study provide acceptable values for filtration efficiency and quality factor for filtration applications. Additionally, they serve as a guideline for subsequent experiments to produce uniform and continuous nanofibers with desired diameter for future applications in absorbent media (intermediate absorbent layers) of respirators.