Magnetic vortex core observation in circular dots of permalloy

Spin structures of nanoscale magnetic dots are the subject of increasing scientific effort, as the confinement of spins imposed by the geometrical restrictions makes these structures comparable to some internal characteristic length scales of the magnet. For a vortex (a ferromagnetic dot with a curling magnetic structure), a spot of perpendicular magnetization has been theoretically predicted to exist at the center of the vortex. Experimental evidence for this magnetization spot is provided by magnetic force microscopy imaging of circular dots of permalloy (Ni(80)Fe(20)) 0.3 to 1 micrometer in diameter and 50 nanometers thick.

Propagation of a magnetic domain wall in a submicrometer magnetic wire

The motion of a magnetic domain wall in a submicrometer magnetic wire was detected by use of the giant magnetoresistance effect. Magnetization reversal in a submicrometer magnetic wire takes place by the propagation of a magnetic domain wall, which can be treated as a "particle." The propagation velocity of the magnetic domain wall was determined as a function of the applied magnetic field.

Protective activity of the purified protein antigen of Erysipelothrix rhusiopathiae in pigs.

We purified the protein antigen (P64), which contains 66 and 64 kDa proteins, from the alkaline extract (AE) of whole cells of Erysipelothrix rhusiopathiae strain Agata (serovar 5) to determine the protective activity of the antigen against E. rhusiopathiae infection in pigs. The serum titre of antibody against P64 rapidly increased in pigs immunized with 500 and 100 micrograms of P64 and reached maximum values at 3 weeks after the first immunization (1 week after the second immunization). However, the serum antibody titres were not increased in pigs immunized with 20 micrograms of P64 and in nonimmunized pigs. In the pigs immunized with live cell vaccine (acriflavin-fast attenuated strain Koganei 65-0.15), the serum titres of antibody against P64 also increased at 1-2 weeks after immunization. In a pig challenge test performed on immunized and nonimmunized pigs, all nonimmunized pigs showed typical clinical signs of swine erysipelas (fever, erysipeloid, arthritis), while all pigs immunized with 500 and 100 micrograms of P64 and live cell vaccine showed no clinical signs of this disease. In Western blot analysis, sera from pigs immunized with P64 and live cell vaccine strongly reacted with the 64 kDa protein. In contrast, the serum from nonimmunized pigs did not react with any proteins. From these results, it was suggested that a specific antibody against the 64 kDa protein could be increased in pigs immunized with P64 or live cell vaccine and that this anti-P64 antibody has a strong protective effect against E. rhusiopathiae infection in pigs.

[Cross sectional study of the relationship between bone density to diet and life style using ultrasound bone densitometry].

The relationship between bone density to diet and life style was investigated in pre- and postmenopausal women in Kyoto Prefecture in 1994 by a cross-sectional study. Bone densities of 453 women aged 30-86 years were measured by ultrasound bone densitometry. History of pregnancy and delivery, menstruation, medical history, bone and arthral symptoms, life style, food intake frequency, current and past intake of dairy products, and physical activity were examined by self-administered questionnaire. Analysis of covariance and multiple-regression analysis were performed to determine the relation between bone density and life style adjusted for age and obesity index among 151 premenopausal women (PRE), 244 postmenopausal but not sedentary (under 65 years of age) women (POST), and 58 sedentary (older than 65 years of age) women (SED). The results were as follows; 1) A marked age-related decline in bone density was observed at 45-55 years of age. The correlation coefficient between age and bone density was significant at -0.65 (p < 0.01). 2) Obesity index and bone density were positively correlated in each group. 3) Among the PRE group women, there was no relation between life style and bone density. Those who experienced bone fractures tended toward low bone density. Among the POST group, time since menopause, exercise, and current milk intake were significantly correlated with bone density. In the SED group, women with arthralgia showed significantly lower densities. 4) From multiple-regression analysis, age, obesity index, and milk intake during childhood were shown to be related to bone density in each group.