Protective Properties of a Microstructure Composed of Barrier Nanostructured Organics and SiOx Layers Deposited on a Polymer Matrix.

The SiOx barrier nanocoatings have been prepared on selected polymer matrices to increase their resistance against permeation of toxic substances. The aim has been to find out whether the method of vacuum plasma deposition of SiOx barrier nanocoatings on a polyethylene terephthalate (PET) foil used by Aluminium Company of Canada (ALCAN) company (ALCAN Packaging Kreuzlingen AG (SA/Ltd., Kreuzlingen, Switzerland) within the production of CERAMIS® packaging materials with barrier properties can also be used to increase the resistance of foils from other polymers against the permeation of organic solvents and other toxic liquids. The scanning electron microscopy (SEM) microstructure of SiOx nanocoatings prepared by thermal deposition from SiO in vacuum by the Plasma Assisted Physical Vapour Deposition (PA-PVD) method or vacuum deposition of hexamethyldisiloxane (HMDSO) by the Plasma-enhanced chemical vapour deposition (PECVD) method have been studied. The microstructure and behavior of samples when exposed to a liquid test substance in relation to the barrier properties is described.

Efficacy of external warming in attenuation of hypothermia in surgical patients.

BACKGROUND/AIM: Hypothermia in surgical patients can be the consequence of long duration of surgical intervention, general anaesthesia and low temperature in operating room. Postoperative hypothermia contributes to a number of postoperative complications such as arrhythmia, myocardial ischemia, hypertension, bleeding, wound infection, coagulopathy, and prolonged effect of muscle relaxants. External heating procedures are used to prevent this condition. The aim of this study was to evaluate the efficiency of external warming system in alleviation of cold stress and hypothermia in patients who underwent major surgical procedures. METHODS: The study was conducted in the Military Medical Academy in Belgrade. A total of 30 patients of both genders underwent abdominal surgical procedures, randomly divided into two equal groups: the one was externally warmed using warm air mattress (W), while in the control group (C) surgical procedure was performed in regular conditions, without additional warming. Oesophageal temperature (Te) was used as indicator of changes in core temperature, during surgery and awakening postoperative period, and temperature of control sites on the right hand (Th) and the right foot (Tf) reflected the changes in skin temperatures during surgery. Te and skin temperatures were monitored during the intraoperative period, with continuous measurement of Te during the following 90 minutes of the postoperative period. Heart rates and blood pressures were monitored continuously during the intraoperative and awakening period. RESULTS: In the W group, the average Te, Tf and Th did not change significantly during the intraoperative as well as the postoperative period. In the controls, the average Te significantly decreased during the intraoperative period (from 35.61 ± 0.35 °C at 0 minute to 33.86 ± 0.51°C at 120th minute). Compared to the W group, Te in the C group was significantly lower in all the observed periods. Average values of Tf and Th significantly decreased in the C group (from 30.83 ± 1.85 at 20th minute to 29.0 ± 1.39°C at 120th minute, and from 32.75 ± 0.96 to 31.05 ± 1.09°C, respectively). CONCLUSION: The obtained results confirm that the external warming using warm air mattress was able to attenuate hypothermia, i.e. substantial decrease in core temperature, compared with the similar exposure to cold stress in the control group.

Physiological tolerance to uncompensated heat stress in soldiers: effects of various types of body cooling systems.

BACKGROUND/AIM: In military services, emergency situations when soldiers are exposed to a combination of nuclear, biological and chemical (NBC) contamination combined with heat stress, are frequent and complex. In these specific conditions, usage of personal body cooling systems may be effective in reducing heat stress. The present study was conducted in order to evaluate the efficiency of four various types of contemporary personal body cooling systems based on the "Phase Change Material" (PCM), and its effects on soldiers' subjective comfort and physiological performance during exertional heat stress in hot environments. METHODS: Ten male soldiers were voluntarily subjected to exertional heat stress tests (EHSTs) consisted of walking on a treadmill (5.5 km/h) in hot conditions (40 degreesC) in climatic chamber, wearing NBC isolating impermeable protective suits. One of the tests was performed without any additional cooling solution (NOCOOL), and four tests were performed while using different types of cooling systems: three in a form of vests and one as underwear. Physiological strain was determined by the mean skin temperature (Tsk), tympanic temperature (Tty), and heart rate values (HR), while sweat rates (SwR) indicated changes in hydration status. RESULTS: In all the cases EHST induced physiological response manifested through increasing Tty, HR and SwR. Compared to NOCOOL tests, when using cooling vests, Tty and Tsk were significantly lower (on 35th min, for 0.44 +/- 0.03 and 0.49 +/- 0.05 degrees C, respectively; p < 0.05), as well as the average SwR (0.17 +/- 0.03 L/m2/h). When using underwear, the values of given parameters were not significantly different compared to NOCOOL tests. CONCLUSIONS: Using a body cooling system based on PCM in the form of vest under NBC protective clothes during physical activity in hot conditions, reduces sweating and alleviates heat stress manifested by increased core and skin temperatures and heart rate values. These effects directly improve heat tolerance, hydration state, decrease in the risk of heat illness, and extends the duration of soldiers' exposure to extreme conditions.

Ejection experience in Serbian Air Force, 1990-2010.

BACKGROUND/AIM: Ejection injuries are the problem for air forces. The present risk for injuries is still too high, approximately 30-50%. The aim of this study was to determine factors responsible for and contributing to injuries in the Serbian Air Force (SAF) in the last two decades. METHODS: All ejection cases in the SAF between 1990 and 2010 were analyzed. The collected data were: aircraft type, ejection seat generation, pilots" age and experience, causes of ejection, aeronautical parameters, the condition of aircraft control and types of injuries. For ease of comparison the US Air Force Safety Regulations were used to define major injuries: hospitalization for 5 days or more, loss of consciousness for over 5 min, bone fracture, joint dislocation, injury to any internal organ, any third-degree burn, or second-degree burn over 5% of the body surface area. RESULTS: There were 52 ejections (51 pilots and 1 mechanic) on 44 airplanes. The ejected persons were from 22 to 46 years, average 32 years. Major injuries were present in 25.49% cases. Of all the ejected pilots 9.61% had fractures of the thoracic spine, 11.53% fractures of the legs, 3.48% fractures of the arms. Of all major injuries, fractures of the thoracic spine were 38.46%. None of the pilots had experienced ejection previously. CONCLUSION: Our results suggest that taking preventive measures is obligatory. Namely, magnetic resonance imaging (MRL) scan must be included in the standard pilot selection procedure and procedure after ejection, physical conditioning of pilots has to be improved, training on ejection trainer has to be accomplished, too.