Methods for improving thermal tolerance in military personnel prior to deployment

Acute exposure to heat, such as that experienced by people arriving into a hotter or more humid environment, can compromise physical and cognitive performance as well as health. In military contexts heat stress is exacerbated by the combination of protective clothing, carried loads, and unique activity profiles, making them susceptible to heat illnesses. As the operational environment is dynamic and unpredictable, strategies to minimize the effects of heat should be planned and conducted prior to deployment. This review explores how heat acclimation (HA) prior to deployment may attenuate the effects of heat by initiating physiological and behavioural adaptations to more efficiently and effectively protect thermal homeostasis, thereby improving performance and reducing heat illness risk. HA usually requires access to heat chamber facilities and takes weeks to conduct, which can often make it impractical and infeasible, especially if there are other training requirements and expectations. Recent research in athletic populations has produced protocols that are more feasible and accessible by reducing the time taken to induce adaptations, as well as exploring new methods such as passive HA. These protocols use shorter HA periods or minimise additional training requirements respectively, while still invoking key physiological adaptations, such as lowered core temperature, reduced heart rate and increased sweat rate at a given intensity. For deployments of special units at short notice (< 1 day) it might be optimal to use heat re-acclimation to maintain an elevated baseline of heat tolerance for long periods in anticipation of such an event. Methods practical for military groups are yet to be fully understood, therefore further investigation into the effectiveness of HA methods is required to establish the most effective and feasible approach to implement them within military groups.

Temperature Influences at the Myoelectric Level in the Upper Extremities of the Human Body

Objective: Nowadays, surface electromyography (sEMG) signals are used for a variety of medical interaction applications along with hardware and software interfaces. These signals require advanced techniques with different approaches that enable processing the sEMG signals acquired in the upper limb muscles of a person. Methods: The purpose of this article is to analyze the sEMG signals of the upper limb of a person exposed to temperature changes to envisage its behavior and its nature. The anticipated diagnostic is a key factor in the health field. Therefore, it is very important to develop more precise methods and techniques. For the present study, a heat chamber that allows controlling the temperature of the area where the patient rests his or her hand was designed and implemented. With the appropriate hardware interfaces, the sEMG signals of the hand were registered with MatLab/Simulink software for further analysis. The article explains the analysis and develops knowledge, through a probabilistic approach regarding the change in the sEMG signals. Results: The results show that there is an activity in the sEMG signal response due to changes in temperature and it is feasible to detect them using the proposed method. Conclusion: This finding contributes to research that seeks to characterize temperature’s effect in the biomedical field.

INNOVATIVE SOLUTIONS OF ADSORPTION CLEANING RECIRCULATING AIR FOR ELECTRIC TESTS OF ELECTRIC PRODUCT TESTS

The purpose of the study of this work: to provide a scientific justification for the energy-saving device to maintain the normalized parameters of the recirculated air in special “clean” rooms, to derive formulas for calculating the adsorption material during the operation of the installation. The novelty of the constructive solution is protected and confirmed by patents of the Russian Federation for the invention. Methods. The volume of adsorbent determined by this method is placed in a tank with a recirculation loop, which includes: a cleaning unit nozzle, the inner surface of which is spring-loaded with a grid placed on the side of a moving air flow and a grid around the entire outlet section of the expanding nozzle. Spring-loaded mesh, placed on the side of a moving air flow, is made according to the profile of the velocity profile of the moving air flow, which is caused by the manifold speed impact on the adsorbent grains, horizontally arranged layers in order to level the absorbing capacity of silica gel KSM-5 throughout the drying device and use in the system recirculation of the air supplied by the fan leads to a probable entry of the vaporous mass of oil into the stream being cleaned, and the analysis of scientific and technical oh showed no literature data on the nature of such contaminants granular filter material, resulting in the need to study the penetration of the oil by volume adsorbent per cycle electrical testing of electronic devices in a heat chamber. Results. Based on the analysis of well-known foreign and domestic theoretical and experimental studies, there was no development related to vibration effects on the efficiency of adsorption drying of recirculated air for electrical thermal testing of electronic products. An adsorption unit has been developed with a horizontal arrangement of an adsorbing substance for treating air under conditions of vibration effects. Conclusion The installation developed by the authors passed laboratory and industrial tests at the Mayak plant of Kursk and was recommended for implementation as a resource-saving constructive solution protected by patents of the Russian Federation for invention. Keywords: special premises electrical testing of electronic products, recirculation circuit in the chamber for temperature testing - heat chamber, adsorption drying, transparent body of the drying device, oil contamination.

CHANGE OF FUNCTIONAL AND LABORATORY PARAMETERS AFTER COMPENSATION OF ACUTE BLOOD LOSS WITH COOLED HYPERTONIC SOLUTION IN EXPERIMENT

Relevance.High efficiency of hypertonic (hyperosmolar) solutions in acute blood loss is known. However, data on changes in the body, developing as a result of infusion of such drugs (including cooled) in the providing of care after acute blood loss is limited or absent. This fact complicates the development of tactics in their use, especially in emergency situations at low temperatures.Intention.To reveal features of functional and laboratory indicators In experiments on animals as a result of infusion of warm (+22 °С) or the cooled (–3 °С) hypertonic solution based on hydroxyethyl starch and sodium chloride (HyperHAES, further – HHES) at the acute blood loss of 50 % of blood volume (BV).Methodology.Animals (20 male sheep) with modeled blood loss were distributed into 2 experimental and 2 control groups of 5 animals each. Sheep in the 1st experimental group were placed in the heat chamber with temperature –7 °С for 15 min. Then they underwent the intravenous infusion of a cooled HHES at a dose of 4 ml/kg of weight through the jugular vein with a disposable syringe (volume 20 ml) evenly with a speed of 60 ml per minute. After that they were left in the heat chamber until the time of 1 hour in total. Individuals in the 2nd experimental group were injected with an equivalent volume of warm solution during the corresponding periods of the experiment at an external temperature of +22 °C. 1 hour after beginning of the infusion all animals were intravenously injected with colloidal solution based on hydroxyethyl starch (“Voluven”) at an external temperature of +22 °C. During 1 day the dynamics of rectal temperature, arterial pressure, heart rate and respiratory movements, osmolarity of blood plasma and content of osmotically active components, quantitative indicators of red blood were evaluated.Results.Animals at a temperature of +22 °C or at a temperature of –7 °C died in (82 ± 3) min and (70 ± 5) min (p < 0.05) respectively after the start of exfusion. Intravenous fluids (warm or cooled HHES) ensured the survival in 100 % of cases. As a result of blood loss, subsequent infusion of cooled HHES and following presence in the heat chamber, rectal temperature in sheep decreased by 4.9 °C (14.2%, p < 0.05) relative to the initial values. Two and 4 min after infusion of cooled or warm HHES systolic blood pressure increased by 24.9 % (p < 0.05) and 14.9 % (p < 0.05), respectively, and were restored to the normal level during the following 40 min. Infusion of “Voluven” contributed to the stabilization of blood pressure within 1 day after infusion of HHES. Blood loss led to increased heart rate by 2.1 times (p < 0.05), infusion of HHES slightly reduced the severity of tachycardia. Within 10 minutes after the introduction of cooled HHES, dynamics of heart rate was less stable. Infusion of warm or cooled HHES increased osmolarity of blood plasma by 9.5–9.9 % (p < 0.05), which was associated with an increase of sodium and glucose concentrations in blood. Infusion of “Voluven” reduced osmolarity of blood plasma, which became similar to initial values at the end of Day 1 after infusion of HHES. Blood loss, infusion of HHES and “Voluven” decreased quantitative indicators of red blood via removal of red blood cells from the bloodstream, as well as compensatory and post-transfusion hemodilution.Conclusion.The infusion of warm or cold hypertonic saline (HyperHAES) ensures the survival of experimental animals in post-hemorrhagic period. The positive effect of the drug is associated with compensatory haemodilution (including increased osmolarity of blood plasma), as well as with better functioning of the cardiovascular system. Specific cooled HHES effects include an earlier and pronounced rise in blood pressure. Considering changes in functional and laboratory parameters after infusion of warm or cooled HHES, a reliable system should be developed to remove casualties from emergency areas and to take earlier and complete diagnostic and treatment measures.

ANALYSIS OF FISH THERMAL PROCESSING USING AUTOMATICALLY CONTROLLED HEATING AND DEHYDRATION METHODS

The article deals with the small-size drying plant built in Murmansk State Technical University and used to study advantages and disadvantages of traditional methods of fish thermal processing: convective and infrared. In the course of study the temperature values corresponded to those in technological processes of drying, curing and smoking fish (20-120°C). Poutassou carcasses were taken as raw material (specific surface - 0.2 m2/kg, average weight - 280 g). There are presented the processing parameters: starting weight and end weight, weight loss, processing length, average speed of dehydration, average power supply, energy costs at 30, 50, 80°C. At convective type of processing temperature of fish skin didn’t reach 50°С. Experiment lasted 6.5 hours, average speed of dehydration made 37.8 %/h, energy costs - 6.6 kWt∙h. During infrared type of processing the desired temperature was kept both on the fish skin and in the heat chamber during one hour, after which temperature in the chamber decreased due to fish warming-up and decreasing power supply to infrared lamps. Experiment lasted 5 hours, average speed of dehydration made 51 %/h, energy costs made 5.6 kWt∙h. The results obtained served as a basis for developing energy efficient combined method of thermal processing which has a two-circuit automatic control system: the first circuit controls temperature in the heat chamber and regulates power in pipe electric heater; the second circuit controls the temperature of the fish and regulates power of the infrared radiation. This method is characterized by higher speed of dehydration (51 %/h), less duration of the process (more than 4 hours) and lower energy costs (4.86 kWt.h). The higher temperature of raw material processing, the less energy intensive the combined method.

Development of a Rapid Screening Method for Selection Against High Temperature Susceptibility in Garden Roses

The decline of garden rose sales over the past 20 years can be partially attributed to the lack of material adapted to a wide range of landscapes, which includes adaptation to high temperature stress. Current methods for evaluating high temperature susceptibility in garden roses are based on field observations, which are time consuming and subjected to ever-changing environmental conditions. A series of experiments were conducted to optimize protocols and compare the use of chlorophyll fluorescence (CFL) and cell membrane thermostability (MTS) by way of electrolyte leakage as methods to screen for high temperature susceptibility. Immature leaves proved better than mature leaves for both CFL and MTS measurements, using either detached leaf or whole plant stress assays. MTS measured on immature leaves stressed in a water bath at 50 °C for 45 minutes proved most consistent in separating rose clones based on high temperature susceptibility. Stressing actively growing plants with flower buds of 2 mm in diameter in a heat chamber at 44 °C for 3 hours resulted in increased flower abscission and leaf necrotic lesions on more susceptible clones when compared with those that were heat tolerant. Combining MTS measurements from immature leaves stressed in a water bath with the flower abscission and leaf necrosis responses 10 days after stress in a heat chamber could be the first step to screen and select against the more susceptible clones in a garden rose breeding program. Power analyses suggest that the proposed MTS protocol would be efficient in detecting differences between clones when the difference in electrolyte leakage is greater than 10%.