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Background: Surgical masks are usually used to protect surgeons from the transmission of disease and germs, as well as preventing the transmission of infectious agents to the environment and others. The mask may not be a suitable environment for the growth and reproduction of microbes. Regarding this, the present study aimed to investigate the feasibility of making antibacterial mask substrate providing high efficiency and low pressure drop. Materials and Methods:For the purpose of the study, nanofiber substrates containing variable amounts of polyethylene terephthalate and copper nitrate were produced using an electrospinning device. The efficiency and pressure drop of antibacterial nanofiber substrates were measured at a particle size range of 260 nm to 1.6 µ. Measurement of the particle number density was accomplished by placing two condensation particle counters on both sides of the filter. Results: Examination of the scanning electron microscope images revealed that the optimal sample contained 25% polymer and 1.5% copper nitrate and had the best morphology at 16 kV. The samples were subjected to electrospinning at different times to examine their efficiency and pressure drop. As the electrospinning time increased from 15 to 60 min, the substrates became thicker, and consequently their efficiencies increased from 13% to 94%; furthermore, the pressure drop increased from 10 to 20 psi. Electrospinning of 60 min resulted in the highest quality factor. Conclusions: As the findings indicated, with the enhancement of electrospinning time, the efficiency of the substrates are increased, and the particle penetration rate of the substrates are reduced. This could be due to the increased thickness of substrates by increasing the electrospinning time.

Background: Sound is an inevitable part of everyday life these days. Hypertension is the most significant preventible risk of immature death all around the world. The main purpose of this study is to answer this question: Does aircraft noise affect blood pressure and heart rate? Methods: To achieve this objective, 100 personnel from the airport were selected. Additionally, 100 personnel were selected for the control group. In this case-control study the B&K dosimeter  model 4444 was used to record noise in a long time duration (8 hours) Blood pressure and heart rates were measured before and after their shift and during their work shift by connecting a dosimeter device to their body and recording noise exposure. SPSS V.22 software was used for statistical analysis. Results: Analyses showed that the average noise intensity in the experimental group was 87.84 ± 2.76, and in the control group, it was 70.01 ± 4.01's. Compared with the control group, mean differences between systolic (P <0/001) and diastolic blood pressure (P=0.047) was significant, while the mean differences in heart rate after the shift not have a significant (P> 0.05). Conclusions: research indicates that unacceptable noise could be a hazardous agent for hypertension. It is suggested that monitoring blood pressure, training workers, and periodic examination to be practiced to decrease blood pressure

Introduction: Today the rate of human beings exposed to electromagnetic fields is increasing deliriously and human beings are being more drowned in the ocean of electromagnetic fields each day. It has been a long time that the effects of electromagnetic fields on organisms has been studied by researchers and due to the long-term researches and the slow impact of fields on life-cycle processes, in a lot of cases a final opinion is impossible. Considering the detrimental effects of being exposed to electromagnetic radiations, this study aimed to determine the relation between electromagnetic radiations and the level of Melatonin and Cortisol hormones of serum (blood) of the male employees of the 230kV substations in Golestan Province.   Materials and Methods: this study has been accomplished with the cross sectional method (descriptive-analytic) on male employees of the 230 kilo-Volt substations in Golestan Province(1396). The results achieved from the serum sample of the case and control groups have been compared, and the measurements and the relation between them has been analyzed, using Spss22 software.   Results: 100 % of the measured electric field intensity and magnetic flux density of the 230kV substations in Golestan Province is less than Iran’s occupational limits. There was no significant difference between the average of the level of Cortisol hormone in the case and control groups. The average of the level of Cortisol in the substation job group was not significantly different. There is no significant difference in the average of Cortisol level and age category and work place Conclusion: Electromagnetic radiations do not affect the level of Cortisol hormones of the male employees of the 230 kV substations in Golestan province and the electric and magnetic fields intensity of substations is in the occupational limits of Iran.