نشریه طب کار
سال دوازدهم شماره 4 (پیاپی 41، زمستان 1399)

 Silica nanoparticles have received more attraction in medical and industrial applications due to their unique properties such as small size, the possibility of surface functionalization, ease of production, and low cost. So, it is necessary to study the respiratory toxicity of occupational exposure due to the production and increasing use of silica nanoparticles, especially in the size of 20-40 nm. 

 In vitro, cytotoxicity of silica nanoparticles (SiO2 NPs) in 0.6 -3 mg/ml concentrations were evaluated on human lung epithelial (A549) and human fetal lung fibroblast (MRC5) cells by MTT assay and scanning electron microscopy (SEM) images AFTER 72 hours.

 The MTT assay showed that the cell viability was reduced by increasing the concentration of SiO2 NPs from 0.6 to 3 mg/ml in both types of cells. In 1.6 mg/ml concentration, the half-maximal inhibitory concentration (IC50) of SiO2 NPs on A549 cancer cells, the chance of survival is as such: %46 for A549 cancer and %70 for MRC5 normal cells. The SEM images of normal lung cells (MRC5), which have been exposed to Sio2-NP, showed that the morphology of MRCS cells has transformed from a long shape to a circular one.

 The cytotoxicity of SiO2 NP depends on the concentration of SiO2 NP and the type of cells. By increasing SiO2 NP concentration, the cell viability decreases for both types of cells. Moreover, the cytotoxicity of SiO2 NP against cancer cells (A549) is higher than normal lung cells (MRC5).

 Electrocution is the cause of many deaths in the world annually, that electric current passing between the body and earth can be the reason; thus, it is of great importance to construct the ground protection system using earth pit. This study aimed to investigate the effective environmental conditions on the earthchr('39')s pit resistance using the simulation method.

 In the present study, 192 different experiments were performed and repeated ten times. The parameters evaluated in this study include soil type, reducing agents type, depth, humidity, electrode type, soil density, and electrode placement shape. The resistance value is measured using a three-point ether tester by changing each of them. The obtained data were statistically analyzed, and the results were presented in tables.

 According to the results of the experiments, soil density and moisture are considered the most effective parameters in determining the resistance of the earth pit; so that the value of resistance is significantly reduced by changing these two parameters separately or simultaneously. Also, as density and depth of placement increase, the value of resistance in all experiments had a decreasing trend. This study showed that sand was determined as the worst soil type among the soil types due to its high resistance.

 According to the results of this study, soil density and moisture among the seven parameters under study play a more important role in pit resistance and consequently the severity of an electric shock that should be given more attention to it.

 Shift work is an occupational stressor that influences some workforce. The present study examined shift work disorders among people who work in Hamadan Glass Factory.

 Participants included 210 workers (130 shift workers and 80 day-workers) of Hamadan Glass Factory. The survey of shift workers (SOS) was used to collect information on respondents’ demographic background, gastrointestinal, cardiovascular, psychological disorders, sleep-related problems, musculoskeletal disorders, and adverse effects of shift work on individual, family, and social life. Other information was obtained by studying participating workers’ medical records in the same year. Data were analyzed using SPSS 16.

 The results indicated significant relationships between shift work and variables such as sleeplessness, sleep quality and quantity, stomachache, and diet. Concerning background variables (age, work experience, and marital status), the results of the Kruskal-Wallis test showed a significant relationship between age and musculoskeletal, cardiovascular, and gastrointestinal disorders. Moreover, the results of the Fisher test demonstrated a significant association between work experience and social problems; but none of these background variables were connected with sleep disorders. Considering the effect of shift work (morning, evening, and night) on personal, family, social life, and alertness, chi-square results revealed significance among the three shift-work types. Incidence was higher in night shifts than in morning and evening shifts.

 The findings showed that shift work is more likely to lead to sleep disorders and gastrointestinal diseases, risk of diabetes, infectious diseases, musculoskeletal and cardiovascular disorders than day-work. Shift workers encounter more social problems than novice shift workers.

safety occupational safety researchers have always analyzed climate analysis. Climate can be investigated at different organizational levels. The purpose of the present study was to examine the safety climate among Nain tile factory workers and its relationship with having a history of occupational accidents.

This cross-sectional and descriptive-analytical study was conducted in 2019 among the Nain Tile factory staff. The Nordic Safety Climate Questionnaire (NOSACQ-50) was used to assess the safety climate among workers of the different organizational departments. Out of 252, 142 workers were selected by simple random sampling. Descriptive and analytical statistics were used to analyze the data. The instrumentchr('39')s internal consistency was also calculated by calculating Richardsonchr('39')s coefficient of coefficient 0.942.coefficients were used for analytical analysis. Analyzes were performed in SPSS software version 19 with a significance level of 5%.

The reliability coefficient of the whole questionnaire was calculated 0.95 using Cronbachchr('39')s alpha test. The safety climate score was higher than two in all domains. Safety climate score was significantly correlated with work area and shift type. The highest score of safety climate was in the crusher section as well as in day shift work. There was no significant relationship between safety climate score and other variables of the study.

The safety atmosphere score is affected by the day shift and the workplace section. Therefore, it is suggested to modify the job plan and work shifts to improve the prevailing safety climate.

 Modified Euro Quest questionnaire to assess neurological and psychiatric effects caused by exposure to organic solvents is used. This study investigates the validity, reliability, and usability of the modified Euro Quest questionnaire in Iran.

 This cross-sectional descriptive study was conducted on 206 workers of color and textile industries. Modified Euro Quest questionnaire was translated into Persian by using the forward-backward translation standard method. To evaluate the content validity, convergent validity, internal consistency, and reliability of the questionnaire were used the index CVI, Pearson correlation coefficient, Cronbachchr('39')s alpha, and test-retest. The convergent validity was compared, results of the questionnaire, with results of mini-mental state examination (MMSE) and Multidimensional Fatigue Inventory (MFI).

 The relationship between the modified Euroquest questionnaire was compare with the MMSE test and the MFIchr('39')s questionnaire, Pearson correlation coefficients, and the results showed in order - 0.86 and 0.65, which represents a significant inverse correlation between this questionnaire with MMSE test(p>0.001) And a moderate correlation with the MFIchr('39')s questionnaire(p>0.001). Content validity index (CVI) and intraclass correlation coefficient (ICC) were obtained in order amounts of ≤0.79 and 0.92, which was acceptable. The final questionnaire, Cronbachchr('39')s alpha coefficient, was calculated (α =0.84). 

 The modified Euroquest Persian version is a valuable tool to assess the neurological and psychological effects caused by exposure to organic solvents in Iranian workers.

 Today, the health of human resources in organizations is considered an important arm. This study aimed to investigate the relationship between workplace ergonomics and musculoskeletal pain, joint range of motion (ROM), and spinal deformities in Kermanshah oil refinery staff.

 In the present descriptive-analytical study, all official employees of Kermanshah Oil Refinery (n = 300) were invited to participate in the study, in which 160 employees participated as a statistical sample. The independent variable in this study was workplace ergonomics and the dependent variables including musculoskeletal pain joint ROM and spinal abnormalities. Spinal mouse device was used for spinal deformities assessment, ROSA and RULA forms for workplace ergonomics evaluation, babble baseline inclinometer for measuring the range of motion of the neck, shoulder, thigh, knee, and ankle joints, and Visual Analog scale (VAS) to assess musculoskeletal pain. SPSS software (version 25) and Pearson correlation coefficient were used to investigate the relationship between research variables at a significance level of 0.05.

 The results showed that there was a negative and significant relationship between ergonomics of the workplace with musculoskeletal pain (p<0.05), hip, neck, shoulder, knee, and ankle joints ROM (p<0.05). There was also a positive and significant relationship between workplace ergonomics and spinal abnormalities (lordosis and kyphosis) (p<0.05).

 The findings of the study showed, improper workplace ergonomics is significantly associated with chronic musculoskeletal pain, hyperkyphosis, and hyperlordosis abnormalities, and abnormal range of motion of the joints.

 Accidents are one of the biggest public health problems in the world. At the same time, most young victims are in good health before the accident. World Health Organization studies indicate that in 2020 road accidents will be one of three of the three leading causes of death globally.

 Due to selecting the inner-city route, this study identified the accident hot zones by the number-accident intensity index method in one year. The table of coefficients proposed by the state of Georgia was used to weigh the severity of the accidents (injuries, deaths, and damages).

 In this study, six spatial units were identified as hot zones ( 9/1% ), and 19 spatial units were identified as yellow zones ( 28/8% ); as. Finally, 41 spatial units ( 4100 meters from 6600 meters ) were identified as cold zones ( 62/1% ).

 The most important ways to reduce traffic accidents include the review of traffic signs in terms of the number, size, location, height, and the installation of the speed breaker in the spatial units as hot zones, the construction of an underpass, and the structure of pedestrian bridges with embedding the escalator in some important routs ( hot zones ), developing a comprehensive and long– term training program for improving the driving culture, etc.

 Due to the prevalence of Covid-19 disease in the country, there is a possibility of infecting employees who provide services in different work environments. Our purpose in writing this review article is to assess and analyze studies on the nature of the disease, its causative agent, occupations at risk, and the prevention and control of Covid-19 in the workplace.

 In this study, intending to investigate high-risk occupations and prevent and control Covid-19 disease in the workplace, Google Scholar, PubMed, Scopus databases from 2019 to 2020, and CDC, ACOEM, OSHA, CCHOS, WHO guidelines were assessed by thematic search method. Twenty-four articles and 12 instructions were selected and used in writing this article.

 Studies have shown that many occupations, including healthcare staff, public transport staff, customs and airport staff, waste collection and disposal workers, and bathhouse staff, are at risk for this disease.

 To take effective action to control this emerging disease in the workplace and maintain the health of workers and the continuation of economic activities, first we must better understand this disease and its causative agent, and all components of society must have sufficient information about the nature of the disease, ways of transmitting the virus, and ways to prevent and control Covid-19 disease, this can be effective in reducing lost workdays, absenteeism and preventing the spread of the virus in the community.