Creep mechanism of highly purified V-4Cr-4Ti alloys during thermal creep in a vacuum

Pressurized thermal creep tubes of highly purified V-4Cr-4Ti, the NIFS-Heat2 alloy have been examined following testing in the range 700 to 850°C. It was found that the creep stress exponent of the NIFS-Heat2 alloy is about 5 and that the characteristic creep mechanism was the dislocation creep usually observed in pure metals. The apparent activation energy of creep deformation is about 210kJ/mol in the temperature range 700 to 850°C. Creep deformation was considered to be controlled by climb-controlled dislocation glide at 850°C, where sub-grain boundary structure predominates and consists of dislocation dipole structures and pile-ups of dislocations

Cascade Damages and Their Kinetic Behavior in Ceramics Irradiated with Fission- and Fusion-Neutrons

The cascade damage and its kinetic behavior in various kinds of ceramics irradiated with fission- and fusion-neutrons have been examined through transmission electron microscopy. Fission- and fusion-neutrons introduce relatively dilute concentration of point defects around primary knock-on atoms through the displacement cascade process in low-Z ceramics. Higher concentration of point defects, which induces the contrast corresponding to the cascade damage though TEM, is induced only in covalent crystals consisting of relatively high-Z elements. The nucleation and growth process of interstitialloops is strongly affected by the crystal structure and structural vacancy

Treatment algorithm of ACTH deficiency

Objective : To examine diagnostic performance of corticotropin-releasing hormone (CRH) test combined with baseline dehydroepiandrosterone sulfate (DHEA-S) in patients with a suspect of central adrenal insufficiency. Methods : Patients (n=215) requiring daily or intermittent hydrocortisone replacement, or no replacement were retrospectively checked with their peak cortisol after CRH test and baseline DHEA-S. Results : None of 106 patients with the peak cortisol ≥ 17.5 μg / dL after CRH test required replacement, and all 64 patients with the peak cortisol < 10.0 μg / dL required daily replacement. Among 8 patients with 10.0 μg / dL ≤ the peak cortisol < 17.5 μg / dL and baseline DHEA-S below the reference range, 6 patients required daily replacement and 1 patient was under intermittent replacement. Among 37 patients with 10.0 μg / dL ≤ the peak cortisol < 17.5 μg / dL and baseline DHEA-S within the reference range, 10 and 6 patients were under intermittent and daily replacement, respectively. Conclusions : No patients with the peak cortisol ≥ 17.5 μg / dL required hydrocortisone replacement, and all patients with the peak cortisol below 10.0 μg / dL required daily replacement. Careful clinical evaluation was required to determine requirement for replacement in patients with 10.0 μg / dL ≤ the peak cortisol < 17.5 μg / dL even in combination with baseline DHEA-S

ICTP as a marker for atherosclerosis

Carboxy-terminal telopeptide of type I collagen (ICTP) is generated through matrix metalloproteinase (MMP)-dependent type I collagen digestion, and has been widely utilized as a biomarker for bone turnover. The fact that atherosclerotic lesions are rich in both type I collagen and MMP-producing macrophages led to the hypothesis that serum ICTP concentrations may serve as a non-invasive clinical biomarker for atherosclerosis. Therefore, the association of serum ICTP concentrations with the maximum intima-media thickness (IMT) of carotid arteries, a surrogate index of systemic atherosclerosis, or brachial-ankle pulse wave velocity (baPWV) in patients with atherosclerotic risk factors was evaluated. A total of 52 male and 65 female (mean age: 62.8 yrs) patients without renal failure, malignancies or bone diseases known to affect serum ICTP concentrations were recruited. Patients with max IMTs ≥1.1 mm showed significantly higher serum ICTP concentrations compared with patients with max IMTs <1.1 mm (3.33 ± 0.97 vs 2.82 ± 0.65 ng/mL, p<0.05). Serum ICTP concentration was also positively correlated with max IMT (p<0.001) or baPWV values (p<0.05). Multivariate analyses also revealed that serum ICTP concentrations were correlated with max IMT (p<0.001; 95% CI 0.200 to 0.454). These results suggest that serum ICTP concentrations can be used as a non-invasive biomarker for systemic atherosclerosis