Mohamed Zaki Ramadan

Effects of protective respiratory devices and physical workloads in harsh weather conditions on individuals' physiological measures and exertion ratings

OBJECTIVE Although respiratory device is an essential item to protect the wearer from hazardous gases and dust, it tends to increase heat load on the workers. The goal of this paper was to select the appropriate respiratory devices that can be used in a harsh weather under different work-loads. METHODS Sixteen young male participants participated in this study. Participants exercised on an ergometer bike in a laboratory at 30% and 50% of their physical workloads, in temperature and humidity controlled environments (30°C and 40°C dry bulb temperatures with 50% and 90% Relative Humidity), while wearing six different respiratory devices. The effects on the participants body functions (e.g., heart rate, aural canal temperature and blood pressure), and their subjective exertion ratings were measured. RESULTS Results proved that when wearing protective devices in hot environments, all physiological measures as well as exertion ratings were significantly increased. However, wearing half-face masks with two inlets exerted less stresses on the workers physiological measures and subjective rating. CONCLUSIONS This study recommended wearing half-face masks with two inlets to be used when performing tasks at hot environmental conditions.

Development of a device to reduce the risk of injury in handling unstable loads

BACKGROUND Manual material handling (MMH) task is the most common cause of work-related musculoskeletal disorders (MSDs). Operators carrying unstable loads were recently shown to be at greater risk of back injury compared to workers carrying stable loads. OBJECTIVE This study focused on developing a device to minimize trunk muscle activity and cardiovascular demand while handling a 19-liter bottle. METHOD After evaluating several designs, one was selected to be developed, manufactured and tested through an experimental study. Healthy participants (n = 42) manually carried a 19-liter bottle. The carrying technique (i.e., carrying a lateral load while holding the load using the dominant hand, pulling the load using the developed device, carrying the load on the back using the developing device) was the independent variable. The muscular activities (e.g., neck extensor, upper trapezius, pectoralis major, deltoid medial, rectus abdominis, and erector spinae muscles of the dominant side), cardiac costs, plantar pressures, walking speeds, and subjective measures were the dependent variables. RESULTS Results show that carrying the developed device like a backpack significantly reduced trunk muscle activity, cardiovascular demand, and plantar pressure compared to the usual practice. The present results suggest that carrying a 19-liter water bottle using the developed device is likely to contribute to lower MSDs. CONCLUSION Implementation of the develop device recommended to lessen the risk of injury when handling unstable loads such as liquids.

Evaluating the User Physical Stresses Associated with Watching 3D and 2D Displays over Extended Time Using Heart Rate Variability, Galvanic Skin Resistance, and Performance Measure

This paper compares the effects of viewing videos with 2D and 3D displays with regard to the viewing distance (3 vs. 6 , where is the height of the screen) and viewing time to determine the physical stresses in terms of heart rate variability, galvanic skin resistance (GSR), and performance of the viewer (percent of correct responses). Twenty healthy male university students with a mean age ± standard deviation of 27.7 ± 2.53 years participated in this study as volunteers. None had color blindness, and all had normal vision acuity. Display type by viewing distance interaction had a significant effect on most of the heart rate variability measures and associated with watching time for the GSR responses. The results concluded that viewing the 3D display from a short viewing distance produced significantly high physical stresses compared to viewing the 2D display from the same short viewing distance. However, the 3D display seemed to impart lower physical stress than the 2D display at long viewing distances. The findings of this study indicate that physical stresses appeared significant at close viewing distance after watching a 3D display for 50 min and increased with continued watching time. In addition, viewer performance was higher for the 3D compared to 2D display type.

The association of sleep deprivation on the occurrence of errors by nurses who work the night shift.

Purpose: To determine the influence of sleep deprivation on the occurrence of errors by registered nurses working in night shift in intensive care departments. Methods: The study utilized a multi-part questionnaire which included items about demographic characteristics, reported medical errors, and Pittsburgh Sleep Quality Index (PSQI) 300 questionnaires were distributed to registered nurses working in intensive care departments. 138 of the 153 (51% response rate) collected questionnaires were analyzed using correlation and stepwise logistic multiple regression. Results: Registered nurses who were sleep deprived had worse sleep quality in terms of high PSQI than those who were not. None of the demographic variables was statistically significant, not providing evidence that these variables may explain odds for being sleep deprived in the population. Conclusions: Work schedule changes, offering shorter periods of time on night shift and less working hours in the week may lead to better sleep quality and less sleep deprivation.