Magnetite (Fe3O4) microcapsules prepared using a glass membrane and solvent removal

Fine magnetite powders dispersed in polymer solution were encapsulated from an oil-in-water emulsion prepared by an emulsification process employing a porous glass membrane and subsequent evaporation of the solvent. Styrene-based copolymers were dissolved in a magnetic fluid, and then continuously pushed through the pores of glass membrane into the aqueous phase, which had dissolved polyvinyl alcohol (PVA) and sodium dodecyl sulphate (SDS) as a mixed stabilizer. P(styrene-co-acrylic acid) (PS-AA), P(stryrene-co-butyl acrylate) (PS-BA) and styrene-butadiene rubber (SBR) were dissolved in the specially ordered magnetite fluid (25 wt% magnetite dispersed in toluene) separately or as a mixture, and uniform droplets suspending the magnetic particles were obtained. After the evaporation of toluene, PS-AA capsules retained a spherical shape and uniformity, whereas PS-AA/PS-BA capsules revealed a creased surface and broader size distribution. The microcapsules entrapped 30-40 wt% of magnetite, and the encapsulation yield of magnetite was 20-40%. Glass membranes with 9.5, 5.25 and 1.42 microm pore size were employed and 5-40 microm microcapsules were obtained depending on the pore size. When magnetite suspended in chloroform was used, magnetite capsules with broader size distributions were obtained because of the sticking of the droplets to the membrane wall. The advantage of the membrane emulsification which provides uniform sized droplets was lost.

Further evaluation of physical fitness age versus physiological age in women

The present study was conducted to examine further whether adult women who are in a state of high physical fitness possess high physiological functions, and also to investigate whether those who exercise regularly are able to maintain a high quality of various physiological functions. The subjects of this study were 249 healthy Japanese adult women (aged 20-70 years). Of these subjects 30 had jogged or walked regularly for more than 3 years. The physiological ages (PA) and physical fitness ages (FA) of the individuals were estimated from 17 physiological function tests and 5 physical fitness tests, respectively, by principal components analyses. The results indicated that there was a significant correlation between PA and FA (r = 0.76, P < 0.01). To examine this relationship in more detail, the subjects were classified into three physical fitness groups (high, normal and low) based on the deviation from the regression line of FA. Comparison of the mean PA among three physical fitness groups revealed that the high physical fitness groups demonstrated a much lower PA (physiologically younger), while the low physical fitness groups showed a relatively higher PA (physiologically older) in spite of their equivalent chronological ages. From this series of studies, a new concept is proposed where different individuals have different peak physiological capacities, but that these capacities change with age at similar rates. It is suggested that interventions such as exercise and a proper diet for promoting health could increase peak functional capacity but have little effect on the rate of decline.

Effects of habitual physical exercise on physiological age in men aged 20-85 years as estimated using principal component analysis

A population of 221 healthy adult men (aged 20-85 years) was studied to determine whether those who exercised regularly were in good biological condition, and also whether those who were in a state of high physical fitness were in a good state biologically, in terms of physiological age (PA) and physical fitness age (FA) as estimated by principal component analysis. A group of 17 physiological function tests and 5 physical fitness tests were employed to estimate PA and FA, respectively. The results of this study indicated that those who maintained high physical fitness at all age decade groups from 20 to 79 years had a trend towards maintaining a relatively lower PA (physiologically younger). Mean PA and FA of the trained group were younger by 4.7 and 7.3 years, respectively than those of the untrained group. In addition, the slope of regression line of PA on chronological age was more gentle in the trained group than that in the untrained group. These results would suggest that those who are in a state of high physical fitness maintain a relatively good physiological condition, and that regular physical exercise may delay physiological changes normally seen with aging, and consequently may increase the life span.

Biological age versus physical fitness age in women

The purpose of this study was to determine whether adult women who are in a state of high physical fitness are in a good state biologically, in terms of biological and physical fitness ages as estimated by statistical means. The subjects were 65 healthy Japanese women (aged 20-64 years). Biological and physical fitness ages were estimated from the data for 18 physiological function tests and 5 physical fitness tests, respectively, by a principal component model. The correlation coefficient between biological and physical fitness ages was 0.70 (P less than 0.01), which was generally regarded as a high correlation. Therefore, those who were in a state of high physical fitness were considered to be in good biological condition. This result is in good agreement with the results (r = 0.72) from adult men, on whom we reported previously. A statistical analysis to ascertain the relative importance of each contributory variable associated with the variance in biological age suggested that routine clinical evaluation of blood pressure and lipid metabolism might play an important role in determining not only the presence and severity of vascular disease but also the rate of biological aging in women.

Biological age versus physical fitness age

A population of healthy middle-aged (n = 69) and elderly men (n = 12), who participated in a health promotion program, was studied to determine whether really physically fit individuals are in good biological condition, and also whether improvement of physical fitness in the middle-aged and the elderly reduces their "rate of aging". Biological and physical fitness ages of the individuals studied were estimated from the data for 18 physiological function tests and 5 physical fitness tests, respectively, by a principal component model. The correlation coefficient between the estimated biological and physical fitness ages was 0.72 (p less than 0.01). Detailed analyses of the relationship between the estimated biological and physical fitness ages revealed that those who manifested a higher ("older") physical fitness age did not necessarily have a higher biological age, but those who manifested a lower ("younger") physical fitness age were also found to have a lower biological age. These results suggested that there were considerable individual variations in the relationship between biological condition and physical fitness among individuals with an old physical fitness age, but those who were in a state of high physical fitness maintained a relatively good biological condition. The data regarding the elderly men who had maintained a regular exercise program indicated that their estimated biological ages were considerably younger than the expected values. This might suggest that in older individuals regular physical activity may provide physiological improvements which in turn might reduce "the rate of aging".

[Effect of local sustained stress on general oxygen consumption in belt conveyer workers]

The modern mechanization and rationalization of production procedures have recently reduced the intensity of work in most factories. However, it has been pointed out that monotonous inactive work and/or co-operative work can in some sense impose stronger mental and physical stresses which may induce ill health in workers. In this study, assuming the assembly and adjustment of videotape-recorders on a belt conveyor to be representative of monotonous inactive and co-operative work, changes in oxygen consumption, heart rate, blood pressure, body temperature, critical flicker fusion and subjective symptoms of fatigue throughout a workday have been followed for six female workers engaged in this type of work. The main results obtained were as follows: The average oxygen consumption of six workers was 230 ml/min, almost unchanged during the work. The belt conveyor work indicated the metabolic rate of 0.3 in terms of relative metabolic rate. The net daily energy expenditure due to the work was only about 100 kcal. The average heart rate during assembly and adjustment were respectively, about 1.4 and 1.2 times the average heart rate at rest. The blood pressure and the rate of oxygen removal increased slightly as the work progressed in assembly work, but did not increase at all in adjustment work. The critical flicker fusion and body temperature showed little change during the work.