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Gas detection is vital for safety in important industrial and private sectors. Its major significance lies in its proactive risk mitigation, safeguarding lives and resources. In this paper, the focus is on the development of a gas sensor based on quartz crystal microbalance coated with a sensitive layer of zinc oxide (ZnO)--graphene nanocomposite for the detection of volatile organic compounds at room temperature. The incorporation of graphene or reduced graphene oxide is preferred in such applications due to their excellent electrical conductivity, chemical stability, and high surface area. These nanocomposites were synthesized using a chemical method via spray pyrolysis. Various techniques were employed to analyze the coated QCM electrode: contact angle measurements to assess surface wettability, Fourier transform infrared and energy-dispersive X-ray spectroscopy to investigate the composition of the coated electrode, and scanning electron and atomic force microscopies were used to study its surface morphology. These analyses provided valuable insights into the nanocomposite's interaction with the environment, composition, structure, and topography of the sensor's sensitive layer. To evaluate the sensor's sensitivity, the frequency shift (_f) of the coated QCM electrode is monitored when exposed to different gas concentrations of ethanol, toluene, chloroform, humidity, and formamide, ranging from 47 to 142 ppm. The frequency shift indicated the detected gas concentration. The results demonstrate good repeatability and reversibility, which are crucial indicators of a sensor's reliability. This reliability is essential for applications in environmental monitoring or industrial safety, where accurate gas detection is critical. [ABSTRACT FROM AUTHOR]

This retrospective cohort study deals with the causes of death among 57,000 military personnel who served in the French Navy surface vessels and were observed over the period 1975-2000. We successively compared the mortality rate and the specific causes of death between two groups differing in their potential exposure levels to radar. Occupational exposure was defined according to the on-board workplace (radar and control groups). The age-adjusted death ratios of the navy personnel were compared. For all causes of death, the results showed that 885 deaths in the radar group and 299 in the control group occurred (RR = 1.00 (95% CI: 0.88-1.14)). RRs were 0.92 (95% CI: 0.69-1.24) for neoplasms. For the duration of follow-up, the results did not show an increased health risk for military personnel exposed to higher levels of radio frequencies in the radar group, but the number of deaths was very small for some cancer sites.