Variation in displacement energies due to isospin-nonconserving forces.

For mirror nuclei with masses A=42-95, the effects of isospin-nonconserving nuclear forces are studied with the nuclear shell model using the Coulomb displacement energy and triplet displacement energy as probes. It is shown that the characteristic behavior of the displacement energies can be well reproduced if the isovector and isotensor nuclear interactions with J=0 and T=1 are introduced into the f(7/2) shell. These forces, with their strengths being found consistent with the nucleon-nucleon scattering data, tend to modify nuclear binding energies near the N=Z line. At present, no evidence is found that these forces are needed for the upper fp shell. Theoretical one- and two-proton separation energies are predicted accordingly, and locations of the proton drip line are thereby suggested.

Coulomb energy difference as a probe of isospin-symmetry breaking in the upper f p-shell nuclei.

The anomaly in Coulomb energy differences (CEDs) between the isospin T=1 states in the odd-odd N=Z nucleus 70Br and the analogue states in its even-even partner 70Se has remained a puzzle. This is a direct manifestation of isospin-symmetry breaking in effective nuclear interactions. Here, we perform large-scale shell-model calculations for nuclei with A=66 to 78 using the new filter diagonalization method based on the Sakurai-Sugiura algorithm. The calculations reproduce well the experimental CED. The observed negative CED for A=70 are accounted for by the cross-shell neutron excitations from the fp shell to the g(9/2) intruder orbit with the enhanced electromagnetic spin-orbit contribution at this special nucleon number.

Studies on the quantitative autoradiography. II. Radioluminography for quantitative autoradiography of 3H.

The process of obtaining 3H-autoradiographic (ARG) images has been expected for a long time. A few X-ray films with no protection layer are commercially available, however, they do not give a reliable image which can be quantitated and can give good contrast. We tried to fabricate a 3H-type sensor which has no protection layer on a highly sensitive sensor, and called it Imaging plate (IP). The IP is composed of one of the specially designed photo-stimulable phosphors containing of BaFX: Eu2+(X = Cl, Br or I) crystals. Results indicated a good contrast and reliable whole-body ARG image of 3H-labelled glucose with trial IP, which has never been obtained with any X-ray films even if these were subjected to a long exposure time. The ARG image can be displayed by either black-and-white hard copy or a colored one with the digital display representing relative intensity of photostimulated luminescence (PSL) without back ground (BG) or relative intensity concentration ((PSL-BG)/S), where S was equivalent to 100 pixels (1 mm2). Similarly to the experimental results of 14C, the linear relationship relative intensity and radioactivity of the 3H standard sources was demonstrated with a very wide range of 10(2) to 10(5) dpm/mg upon the exposure for 7d. Also the relationship between relative intensity and relative exposure (radioactivity x exposure time) was linear within the latitude of relative intensity 10(1) to 10(5) (PSL-BG). The trial IP was particularly effective for the quantitative autoradiography of TLC plates.(ABSTRACT TRUNCATED AT 250 WORDS)

Endocrine profiles in the males of a twice-annually spawning strain of rainbow trout, Salmo gairdneri.

The male reproductive cycles of a twice-annually spawning strain of rainbow trout were studied by monitoring the plasma gonadotropin (GtH) and steroid hormone levels in individual fish for more than a year using thirty-five 2.5-year-old mature males. Twenty-five males survived the whole experimental period and were divided into four groups according to the amount of milt and endocrine profiles. In the summer breeding season, milt amount was negligible in Group I and small in Group II with low plasma testosterone, 11-ketotestosterone (11-KT), and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOH-P) levels, whereas both groups showed a large amount of milt and a distinct increase in steroid levels in the winter breeding season (November-January). Group III expelled a large amount of milt in both the summer and winter breeding seasons, and plasma testosterone, 11-KT, and 17 alpha,20 beta-diOH-P showed a clear peak in each breeding season. In Group IV, milt was expelled from December to July, and plasma steroid levels remained high until June before declining to the basal levels; however, these fish failed to mature in the ensuing winter breeding season. Plasma GtH levels in Groups III and IV were significantly higher than those in Groups I and II in the summer breeding season. These results clearly indicate that fish in Group III are twice-annual spawners.

Decrease of plasma sulfur amino acids in essential hypertension.

In order to evaluate the correlation between sulfur amino acids (derived mainly form animal protein in the diet) and blood pressure, free amino acids, including sulfur amino acids such as taurine and methionine, were determined in the plasma and cerebrospinal fluid (CSF) of twelve normotensive subjects and twelve patients with essential hypertension under nutritional control after at least 10 days of standard hospital diet (total calorie and protein content: 2100-2300 Cal per day and 78-83 g per day, respectively). The results obtained were as follows: plasma taurine, serine, methionine and threonine were significantly lower in patients with essential hypertension than in normotensive patients. The levels of plasma taurine, serine, methionine and total sulfur amino acids in individuals correlated inversely to systolic blood pressure. No difference was observed in the CSF levels of free amino acids in normotensive and hypertensive patients. As taurine, methionine and serine are involved in the metabolism of sulfur amino acids, these observations support the view that the decrease in plasma sulfur amino acids may be a factor contributing to elevated blood pressure.