Testing method of plus and minus Gz tolerance at Czech Air Force pilots

Pilots' physiological measurement in conditions of alternating plus and minus Gz (gravitational acceleration) has been done during real flights. The comparison of physiological responses during flights at the safe altitude of 7000 ft and low level flights at the altitude of 900 ft over ground bears on the evaluation of changes of the continuous blood pressure and the heart rate. High level of pilots' plus-minus Gz tolerance is essential requirement to cope with low level flights in agile aircraft. It was proved that the sinusoidal profile during real flights is possible to use for pilots' tolerance to plus and minus Gz load evaluation. A system for the physiological signal acquisition in a cockpit of combat aircraft was developed for this purpose.     

Morphological differences of elite Croatian track-and-field athletes

In this study we present the morphological characteristics of 54 Croatian national level track-and-field athletes. 21 anthropometric body measures were taken on a sample of 15 sprinters (S), 16 endurance sprinters (S4), 10 middle-distance runners (MD) and 13 long-distance runners (LD). Body fat percentage, body mass index and somatotype were also calculated. Canonical discriminative analysis showed significant difference between the athletes of various running events, in the measures of body volume and body fat, while no significant difference was found in the variables of longitudinal and transversal dimensions of the skeleton. ANOVA and Student t-test for independent samples showed statistically significantly higher thigh and lower leg circumference in sprinters, as well as greater upper arm skinfold in middle-distance runners. The mesomorphic component is a dominant characteristic of somatotype of the runners in all events, whereas the ectomorphic component is the least marked.     

Influence of diet and physical exercise on plasma lipid concentrations in an homogeneous sample of young Spanish Air Force pilots

This study evaluates the influence of diet and physical exercise on plasma lipid concentrations — total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), and the TC:HDL-C ratio, in a homogeneous (age, sex and anxiety levels) group of young pilots divided into the following groups: A. uncontrolled diet and exercise programme; B. controlled diet and uncontrolled exercise programme; C. controlled diet and exercise programme (n=90). The dietary intake was a typical Mediterranean diet, which was supervised by the Flight Surgeon. The exercise was based on a physical training programme for pilots, directed by the Physical Training Officer. The State-Trait Anxiety Inventory test was performed to evaluate the anxiety levels. This test was supervised by a psychologist. The results showed a marked difference in all the lipid parameters studied between groups with an ad libitum diet versus groups with a controlled diet, this difference being demonstrated by TC and TG concentrations lower in the group with a controlled diet, than in the group with an ad libitum diet. A difference in HDL-C concentrations and TC :HDL-C ratio was found between groups with regular physical training (high HDL-C concentration and low TC:HDL-C ratio) versus groups with unlimited exercise (low HDL-C concentrations and high TC: HDL-C ratio). No differences in the state and trait of anxiety were found among any of the groups. Nevertheless, all the pilots showed a considerable increase in their anxiety state over their own anxiety trait.     

Viral Hepatitis in the Air Force

The reported incidence of viral hepatitis in the Air Force has increased over the past 10 years. The total number of days lost from duty has declined as has the average number of days lost per case. Distribution of USAF reported cases has been roughly equally divided among the three diagnostic categories, in contrast to the total United States reported distribution. Relatively few USAF cases have had a documented history of drug abuse since we began collecting this information, and the proportion of these cases has steadily declined. Finally, these diseases still represent significant economic and operational costs to the Air Force so that prevention and control remain important items of concern to commanders and the medical service.     

Morphological status of the shoot systems of Psilotaceae

Brittonia - This paper evaluates the morphological bases for Bierhorst’s recent proposals of the systematic alliance of Psilotaceae with leptosporangiate ferns. In particular it examines the...     

Monitoring of pre-frontal oxygen status in helicopter pilots using near-infrared spectrophotometers

Background

There are few in-flight studies of cognition-related cerebral oxygen status in helicopter pilots.

Methods

Four male helicopter pilots volunteered for nine sorties during visual flight in a BK117 and UH-60J. The pilots' pre-frontal oxy-hemoglobin (O₂Hb) and deoxy-hemoglobin (HHb) concentration were continuously monitored from the right/left sections of the forehead using near-infrared spectrophotometers with a consideration of motion artifacts.

Results

The concentration of O₂Hb progressively increased (13.98 μmol?L^-1 as a maximum increased concentration) in both the right/left sections of the forehead from the basal level during the heightened cognitive demand of helicopter flight. There was comparatively little change (4.32 μmol?L^-1 as a maximum increased concentration) in HHb concentration during measurement of helicopter flight. HHb changes were apparently not affected by a heightened cognitive demand of helicopter pilots.

Conclusion

These results demonstrate that near-infrared spectroscopy, especially O₂Hb measurements, provides a sensitive method for the monitoring of cognitive demand (maneuvers) in helicopter pilots.

     

A survey on the cytogenetic status of the Croatian general population by use of the cytokinesis-block micronucleus assay

The cytokinesis-block micronucleus assay (CBMN) was used to assess the variability and determine possible influences of external and internal factors on the background levels of cytogenetic damage in peripheral blood lymphocytes (PBL) of 50 healthy volunteers selected at random from the general population of Croatia. The mean MN frequency for all subjects was 4.74+/-0.31 per 1000 cells and the mean cytokinesis-block proliferation index (CBPI) was 1.82+/-0.01. The mean frequency of nucleoplasmic bridges (NPB) for all subjects was 0.06+/-0.04 and of nuclear buds (NB) 0.12+/-0.05. The canonical correlation analyses indicate a positive non-significant correlation between the MN frequency and age, gender and smoking habits. Results of factor structure and canonical weights showed that age and gender rather than smoking habits control the incidence of MN in PBL of healthy volunteers. The lowest median value of MN was observed in subjects younger than 30 years (both smoking and non-smoking). Generally, non-smokers had lower median values of MN compared to smokers. In non-smokers, males showed lower micronucleus incidence than females. Within the non-smokers smaller differences in the median values of MN between subgroups (male and female; age subgroups) were observed. Among smokers, females had a two-fold higher median value of MN frequency than males, but this difference was not significant (p=0.2643, Mann-Whitney U test). Canonical correlation analyses indicate a strong and significant correlation between cell proliferation parameters (M1-M4 and CBPI) and age, gender and smoking habits. The most sensitive parameters were M3 and M4. Age had the strongest effect on M3, while M4 was highly influenced by smoking habits. Gender had an equal non-significant effect on both parameters. The usefulness of the new criteria for the cytokinesis-block MN assay measuring DNA damage as a sensitive biomarker in biomonitoring studies is confirmed.