Tunable Magnon-Magnon Coupling Mediated by Dynamic Dipolar Interaction in Synthetic Antiferromagnets.

We report an experimental observation of magnon-magnon coupling in interlayer exchange coupled synthetic antiferromagnets of FeCoB/Ru/FeCoB layers. An anticrossing gap of spin-wave resonance between acoustic and optic modes appears when the external magnetic field points to the direction tilted from the spin-wave propagation. The magnitude of the gap (i.e., coupling strength) can be controlled by changing the direction of the in-plane magnetic field and also enhanced by increasing the wave number of excited spin waves. We find that the coupling strength under the specified conditions is larger than the dissipation rates of both the resonance modes, indicating that a strong coupling regime is satisfied. A theoretical analysis based on the Landau-Lifshitz equation shows quantitative agreement with the experiments and indicates that the anticrossing gap appears when the exchange symmetry of two magnetizations is broken by the spin-wave excitation.

Switchable giant nonreciprocal frequency shift of propagating spin waves in synthetic antiferromagnets.

The nonreciprocity of propagating spin waves, i.e., the difference in amplitude and/or frequency depending on the propagation direction, is essential for the realization of spin wave-based logic circuits. However, the nonreciprocal frequency shifts demonstrated so far are not large enough for applications because they originate from interfacial effects. In addition, switching of the spin wave nonreciprocity in the electrical way remains a challenging issue. Here, we show a switchable giant nonreciprocal frequency shift of propagating spin waves in interlayer exchange-coupled synthetic antiferromagnets. The observed frequency shift is attributed to large asymmetric spin wave dispersion caused by a mutual dipolar interaction between two magnetic layers. Furthermore, we find that the sign of the frequency shift depends on relative configuration of two magnetizations, based on which we demonstrate an electrical switching of the nonreciprocity. Our findings provide a route for switchable and highly nonreciprocal spin wave-based applications.

Association of habitual physical activity measured by an accelerometer with high-density lipoprotein cholesterol levels in maintenance hemodialysis patients.

After confirming the relationship between high-density lipoprotein cholesterol (HDL-C) levels and mortality in hemodialysis patients for study 1, we investigated the effect of physical activity on their HDL-C levels for study 2. In study 1, 266 hemodialysis patients were monitored prospectively for five years, and Cox proportional hazard regression confirmed the contribution of HDL-C to mortality. In study 2, 116 patients were recruited after excluding those with severe comorbidities or requiring assistance from another person to walk. Baseline characteristics, such as demographic factors, physical constitution, primary kidney disease, comorbid conditions, smoking habits, drug use, and laboratory parameters, were collected from patient hospital records. An accelerometer measured physical activity as the number of steps per day over five consecutive days, and multiple regression evaluated the association between physical activity and HDL-C levels. Seventy-seven patients died during the follow-up period. In study 1, we confirmed that HDL-C level was a significant predictor of mortality (P = 0.03). After adjusting for patient characteristics in study 2, physical activity was independently associated with HDL-C levels (adjusted R (2) = 0.255; P = 0.005). In conclusion, physical inactivity was strongly associated with decreased HDL-C levels in hemodialysis patients.

The degree of workers' use of annual health checkup results among Japanese workers.

In Japan, the Industrial Safety and Health Law obliges all workers to undergo annual health checkups in their workplaces. At the plant for this study, workers who have one or more abnormal findings pointed out in their annual health checkups are summoned by occupational health staff and subsequently attend health consultations conducted by occupational health nurses each year. We investigated what kinds of health consultations have improved the workers' use of the results of their annual health checkups by an anonymous self-administered questionnaire survey. In addition, we discussed the associations with the multidimensional health locus of control (MHLC) and the degree of the workers' use of these results. A total of 837 questionnaires were analyzed. The average age of the respondents was 47.9 yr (range: 19-68 yr). The main results suggest that it is necessary for occupational health staff to give workers practical advice to improve their lifestyle habits and convey to them the effectiveness of preventive health behaviors. Workers with high scores in the belief in the "internal health locus of control (IHLC)" and low scores in the "chance health locus of control (CHLC)" use the results of their health checkups to help them manage their own health.

Factors associated with workers' perceived helpfulness of and need for health consultations given by an occupational physician at a Japanese manufacturing plant.

OBJECTIVE: The aim of this study was to clarify measures for improving the functionality of health consultations by occupational physicians, by examining factors associated with workers' perceived helpfulness of, and need for, these consultations. METHODS: An anonymous self-administered questionnaire survey was conducted at a Japanese manufacturing plant. RESULTS: Multiple regression analyses showed that workers' perceived helpfulness of, and need for, health consultations given by an occupational physician was held in common and significantly associated with the occupational physician's dedication and complete protection of privacy. CONCLUSIONS: For health consultations given by occupational physicians to be effective, it is necessary to help employees realize the physicians' outstanding dedication and to convey to the workers the absolute assurance of their privacy protection.

Classification of patients complaining of sick house syndrome and/or multiple chemical sensitivity.

Sick house syndrome (SHS) is a Japanese concept derived from sick building syndrome (SBS), however SHS includes a broader scope of sickness than does SBS. Symptoms of SHS/SBS disappear after leaving the sick house/building, while symptoms of multiple chemical sensitivity (MCS) are elicited by the chance of chemical exposure after leaving the sick house/building. To establish the concept of SHS, we propose to introduce a new classification for SHS. A total of 214 patients complaining of SHS and/or MCS were independently classified using a new classification by clinical ecologists who are experienced physicians with expert knowledge of clinical ecology and general physicians according to disease pathogenesis from clinical records. The classification is as follows: type 1 (symptoms of chemical intoxication), type 2 (symptoms developed possibly due to chemical exposure), type 3 (symptoms developed not because of chemical exposure but rather because of psychological or mental factors), and type 4 (symptoms developed due to allergies or other diseases). The agreements on the classification made by clinical ecologists and general physicians reached 77.1% (Cohen's kappa=0.631), suggesting that this new classification was both apt and accurate. Relations between SHS and allergy/MCS were also studied. The cases classified as SHS type 4 more frequently had allergic past histories than did other types. The proportion of possible MCS cases was higher in the chemical induced SHS group (types 1 and 2) than in other types among male patients. For the universal use in clinical practice, it is necessary to prepare helpful diagnostic criteria of this SHS classification based on pathogenesis and carry our study forward all over the country.

Behavior of new type of rock wool (HT wool) in lungs after exposure by nasal inhalation in rats.

OBJECTIVES: Previous types of rock wool has been recently replaced with high-temperature wool (HT wool). HT wool is characterized by a chemical composition with a higher concentration of Al(2)O(3) and a lower concentration of SiO(2), lower biopersistence, and a higher melting point than previous types of rock wool. To evaluate the safety of HT wool, an asbestos substitute, we examined the biopersistence of HT wool in the lungs, based on changes in fiber count according to the length and fiber size (length and width), by performing a nose-only inhalation exposure study in rats. METHODS: Male Fischer 344 rats were exposed to fibers at the target exposure concentration of 30 mg/m(3) continuously for 3 hours daily for 5 consecutive days. Rats were sacrificed shortly after exposure, and 1, 2, and 4 weeks after exposure, and their lung tissues were incinerated at a low temperature. Then, fiber counts and sizes in the lungs were analyzed using a phase contrast microscope. RESULTS: The fiber count in the lungs 4 weeks after exposure significantly decreased from the baseline value (shortly after exposure). The half-life of fibers calculated from the approximation curve was 34 days for all fibers and 11 days for fibers longer than 20 µm. CONCLUSIONS: Both the length and width significantly decreased 4 weeks after exposure, probably because fibers were ingested by alveolar macrophages, discharged to outside of the body by mucociliary movement, or lysed by body fluid. In future studies, it is necessary to examine the long-term persistence of fibers in the lungs.