Radioactive decay speedup at T=5 K: electron-capture decay rate of (7)Be encapsulated in C(60).

The electron-capture (EC) decay rate of (7)Be in C(60) at the temperature of liquid helium (T=5 K) was measured and compared with the rate in Be metal at T=293 K. We found that the half-life of (7)Be in endohedral C(60) ((7)Be@C(60)) at a temperature close to T=5 K is 52.47+/-0.04 d, a value that is 0.34% faster than that at T=293 K. In this environment, the half-life of (7)Be is nearly 1.5% faster than that inside Be metal at room temperature (T=293 K). We then interpreted our observations in terms of calculations of the electron density at the (7)Be nucleus position inside the C(60); further, we estimate theoretically the temperature dependence (at T=0 K and 293 K) of the electron density at the Be nucleus position in the stable center inside C(60). The theoretical estimates were almost in agreement with the experimental observations.

Serum cholesterol level in normal people: association of serum cholesterol level with age and relative body weight.

Serum cholesterol level was studied in normal subjects in Kasakake Village. The serum cholesterol levels increased significantly with age, from the third to the fifth decade in males and from the third to the seventh decade in females. Thereafter, the levels were maintained in males while declined in females. The mean peak values (+/- SD) were 178 +/- 31 mg/100 ml in males and 207 +/- 37 mg/100 ml in females. The presumptive values of the zero-year-old obtained from the regression lines calculated from the plot of serum cholesterol values against age were 129 mg/100 ml and 112 mg/100 ml in males and females respectively. Throughout the age-range examined in females, the serum cholesterol level was well correlated with the relative body weight determined with modified Broca's method. A similar, but less obvious correlation was demonstrated in males. However, there was not comparable change in the relative body weight against the trend of the serum cholesterol level in both sexes. In the babies normally delivered with full term, the mean cholesterol level (+/- SD) in the umbilical cord blood serum was 65 +/- 13 mg/100 ml and it increased to 150 +/- 46 mg/100 ml during one to three months after birth which was very close to the presumptive values obtained from the regression lines in the adults. There also was significant correlation between the cholesterol value and the body weight. It is concluded that in normal people, age and relative body weight are major and independent determinants of serum cholesterol level from the start of their life.

Enhanced electron-capture decay rate of 7Be encapsulated in C60 cages.

The decay rate of 7Be electron capture was measured in C60 and Be metal with a reference method. The half-life of 7Be endohedral C60 ((7)Be@C(60)) and 7Be in Be metal (Be metal (7Be)) is found to be 52.68+/-0.05 and 53.12+/-0.05 days, respectively. This amounts to a 0.83% difference in electron-capture decay half-life between (7)Be@C(60) and Be metal (7Be). Our result is a reflection of the different electron wave functions for (7)Be@C(60) inside C60 compared to the situation when 7Be is in a Be metal.