Elastic and anelastic properties of ferroelectric SrTi(18)O3 in the kHz-MHz regime

Resonant ultrasound spectroscopy has been used to follow elastic softening in SrTi(18)O3 in the frequency range ∼0.2-1  MHz. A dramatic softening of C44 occurs as the Curie temperature T(c) = 24  K is approached from above or below, which correlates with the development of a central peak in Raman and Brillouin spectra. This is attributed to strong coupling between the acoustic mode and the central peak mode. A weaker anomaly is seen in a resonance mode which is believed to be controlled by 1/2(C11-C12). Significant attenuation accompanies this softening and an additional dissipation peak has also been observed at ∼80-90  K. This extends earlier work by a factor of 150,000× from the 30 GHz regime and helps address the question as to whether the ferroelectricity is stimulated primarily by a soft mode into a homogeneous ground state or by clustering of rhombohedral nanoregions into an inhomogeneous ground state.

Study of Bandgap Profiling Control on Photovoltaic Performance in the Three Stacked Amorphous Solar Cells

A series of systematic experiments has been made on a bandgap profiling control using a-SiGe and a-SiC cells to clarify the cause for the improvement of the photovoltaic performance by the bandgap profiling in the photovoltaic active layer. It has been shown from the analysis that the most important contribution to the cell performance is an optimization of the ambipolar carrier collection by the bandgap profiling. On the basis of the results, an efficiency of 10.1% was obtained at the promising a-SiC/a-Si/ a-SiGe multi-bandgap stacked cell by the bandgap profiling.

Aluminum Foam, “Alporas”: The Production Process, Properties and Applications

The production of foamed aluminum has long been considered difficult to realize because of such problems as the low foamability of molten metal, the varying size of cellular structures, solidification shrinkage and so on. Recently these problems have been solved by a number of researches and some manufacturers produce foamed aluminum by their own methods. We have been employing a batch casting process and manufacturing foamed aluminum under the tradename ALPORAS® since 1986. This paper presents the manufacturing process, physical properties and some typical applications of ALPORAS.

Immunolocalization of ghrelin in the stomach of Sprague-Dawley rat

To investigate the distribution of ghrelin in different regions of stomach in Sprague-Dawley rat, and attempt to compare with those of humans and other mammalian species in this study, the stomach of rats was divided into five sections, cardia, fundus, greater curvature, lesser curvature and pylorus. Immunohistochemistry and Western blotting were performed to investigate the ghrelin-producing cells. The immunolocalization and protein levels of ghrelin differed significantly in different regions of stomach in rats. It was present at a high level in the greater curvature of the pars glandularis, and the lesser curvature. In the fundus and pylorus, no ghrelin immunoreactive cells were detected. In this study, we elucidated the distribution of ghrelin-producing cells in different regions of rat stomach in detail for the first time. It is further considered that the differences of ghrelin distribution in stomach of different species may induce different stimulatory effects on fat accumulation and metabolism.

Inversion of spin photocurrent due to resonant transmission

We report on the inversion of spin-dependent photocurrent via interface localized states formed at the interface of an Fe/n-AlGaAs/GaAs quantum well heterostructure by means of an optical spin orientation technique. A careful adjustment of the excitation photon energy, which is determined by a separate analysis of electroluminescence spectra under a spin injection condition, enables us to explore the spin-dependent characteristics of photoelectron transmission from the quantum well into Fe. The bias dependence of the spin-dependent photocurrent shows clear spikelike features at the voltage which is compatible with the formation of the interface localized resonant states in the Schottky depletion layer.

Role of Polysulfides in Reduction of Elemental Sulfur by the Hyperthermophilic Archaebacterium Pyrococcus furiosus

Polysulfides formed through the breakdown of elemental sulfur or other sulfur compounds were found to be reduced to H(2)S by the hyperthermophilic archaebacterium Pyrococcus furiosus during growth. Metabolism of polysulfides by the organism was dissimilatory, as no incorporation of S-labeled elemental sulfur was detected. However, [S]cysteine and [S]methionine were incorporated into cellular protein. Contact between the organism and elemental sulfur is not necessary for metabolism. The sulfide generated from metabolic reduction of polysulfides dissociates to a strong nucleophile, HS, which in turn opens up the S(8) elemental sulfur ring. In addition to H(2)S, P. furiosus cultures produced methyl mercaptan in a growth-associated fashion.

Formation of a three-dimensional network of V trimers in A2V13O22 (A=Ba, Sr)

We found that in A2V13O22 (A=Ba, Sr), which contains a trilayer slab of VO in the sodium-chloride structure with periodically missing ions, the trimerization of V ions occurs at 290 K (A=Ba) and 380 K (A=Sr). V trimers form a three-dimensional network, but some V ions remain untrimerized in these compounds. The suppression of magnetic susceptibility with trimerization and the existence of a Curie tail at low temperatures, together with the result of NMR measurement, indicate that the V trimers are spin singlet, whereas the untrimerized V ions have a magnetic moment; i.e., there is a spontaneous separation between nonmagnetic and magnetic ions in the crystal.

Application of positron emission tomography in physical medicine

Positron emission tomography (PET) is widely used in the fields of clinical and basic medicine. The PET device utilizes coincidence logic to detect annihilation photons emitted from positrons and estimates physiological functions of human organs in vivo. Radiopharmaceutical 18F- fluorodeoxyglucose (FDG), an analogue of glucose, is trapped metabolically in cells after being administered into the body, and can be substantially used for evaluating physiological and biochemical functions in vivo. Here, we attempted to describe the basics of PET as well as to apply the technique together with 18F-FDG as a tracer for evaluating organ glucose metabolism induced by exercise. Three-dimensional (3D) FDG-PET was applied to normal volunteers who performed exercise to evaluate whole-body glucose metabolism. Regions of interest analysis were drawn on visually defined regions (i.e., lower limbs, thigh, liver, intestine, brain, heart, etc.) to determine radioactivity distribution. FDG-PET clearly showed the recruitment of energy resources from abdominal organs to lower limb skeletal muscles to balance energy expenditures. The results suggested that 3D FDG-PET can be applied as an imaging tool to physical medicine.

[Catamenial pneumothorax with breast cancer treated successfully by goserelin acetate]

A 47-year-old woman with 4 episodes of right pneumothorax related to onset of menstruation was reported. A month ago, she was undergone breast conserving resection for breast cancer. She had recurrent right pneumothorax a month later and operation was performed. Thoracoscopy revealed the presence of multiple fenestrations in the right diaphragm. Thoracoscopic partial resection of the diaphragm was performed. Histopathological findings of the lesion showed spindle cells with hemosiderosis. Immunohistochemistry showed that spindle cells were estrogen receptor (ER) positive and progesterone receptor (PgR) positive, compatible with endometriosis. She was treated by tamoxifen and goserelin acetate for breast cancer and endometriosis. Two years later, gonadotropin releasing hormone (GnRH) analogue was converted from goserelin acetate to leuprorelin acetate. She was diagnosed as having recurrence of right pneumothorax 17 months later and was treated with a chest tube. Additionally, GnRH analogue was re-converted to goserelin acetate. Since then, she has been asymptomatic free for 18 months. A catamenial pneumothorax is rare disease with difficulty of diagnosis and treatment We herein report a case of the disease that was treated successfully by goserelin acetate.

Effect of aphidicolin on DNA synthesis in cultured human thyroid cells

To investigate whether partial inhibition of DNA synthesis affects the growth of thyroid cells, human thyroid cells were cultured in the presence of aphidicolin for 24h. After removal of aphidicolin, the growth of thyroid cells was evaluated by [3H] thymidine uptake and analysis of cell cycle by flow cytometry. In Graves' thyroid cells, [3H] thymidine uptake and the percentage of cells in S+G2/M phase increased during 24 hours after washout of aphidicolin, whereas those were not augmented in normal thyroid cells. Thus, the acceleration of DNA synthesis occurred after the partial inhibition of it by aphidicolin in Graves' thyroid cells, but not in the normal thyroid cells. This phenomenon might, at least in part, explain the difference of growth regulation between Graves' and normal thyroid cells.

Decreased secretion of gonadotropins in a patient with Graves' disease

A 56-year-old female with Graves' disease who presented with decreased secretion of gonadotropins is described. She was admitted to hospital because of her being in a state of confusion. One month before admission she had been diagnosed as having Graves' disease and was treated with methimazole since then. Plasma LH and FSH levels were undetectable, and their responses to LH-RH were extremely decreased in spite of undetectable levels of plasma estradiol and estriol. One year after treatment, both basal and stimulated values of LH and FSH reverted to normal as did those of TSH. Reversible suppression of gonadotropins as described herein has never been reported in cases of Graves' disease.

Ultrasonic propagation of a metallic domain in Pr0.5Ca0.5CoO3 undergoing a photoinduced insulator-metal transition

Femtosecond optical response was investigated on a perovskite-type cobalt oxide, Pr0.5Ca0.5CoO3 during an insulator-metal (I-M) transition accompanied with the change in spin configuration. After photoirradiation at 30 K, the reflectivity showed a sudden and large increase with subsequent variation depending on the observed photon energy. An exact calculation of Maxwell's equations for the Pr0.5Ca0.5CoO3 after the photoirradiation enabled us to observe the ultrafast dynamics of I-M phase transition and the motion of the photonically created metallic domain at the velocity of ultrasonic wave.

Disease-specific expression of VEGF and its receptors in AML cells: possible autocrine pathway of VEGF/type1 receptor of VEGF in t(15;17) AML and VEGF/type2 receptor of VEGF in t(8;21) AML

Various angiogenic factors, such as vascular endothelial growth factor (VEGF) and an associated molecule, placenta growth factor (PlGF), are thought to be important for normal and malignant hematopoiesis. This study examined mRNA expression of VEGF, PlGF and receptors for these molecules in AML cells and identified the disease-specific patterns of expression. AML M3 having t(15;17) abnormality showed highest expression of VEGF and VEGF receptor type 1 (VEGFR1), suggesting the autocrine pathway of VEGF-VEGFR1. Then, t(8;21) AML demonstrated augmented expression of VEGF and VEGF receptor type 2 (VEGFR2), suggesting VEGF-VEGFR2 autocrine pathway. Then, addition of VEGFR2 kinase inhibitor in Kasumi-1, a t(8;21) AML cell line, resulted in marked inhibition of cell growth, although growth inhibitory effect of R2 kinase inhibitor to HL-60 was marginal. In addition, cell cycle analysis study showed S-phase cell population reduction by R2 kinase inhibitor in Kasumi-1, but not in HL-60. This observation is thought to be the rationale for novel molecular target therapy directed to angiogenic molecules.

Association of single nucleotide polymorphisms in the endothelial differentiation sphingolipid G-protein-coupled receptor 1 gene with marbling in Japanese Black beef cattle

Marbling defined by the amount and distribution of intramuscular fat, so-called Shimofuri, is an economically important trait of beef cattle in Japan. The endothelial differentiation sphingolipid G-protein-coupled receptor 1 (EDG1) gene, involved in blood vessel formation, has been previously shown to be expressed at different levels in musculus longissimus muscle between low-marbled and high-marbled steer groups. It is located within the genomic region of a quantitative trait locus for marbling, and thus was considered as a positionally functional candidate for the gene responsible for marbling. In this study, two single nucleotide polymorphisms (SNPs) in the 5' untranslated region (UTR) and the 3' UTR of EDG1, referred to as c.-312A>G and c.*446G>A, respectively, were detected between the two steer groups. The two SNPs were associated with the predicted breeding value for beef marbling standard number by analyses using a population of Japanese Black beef cattle. The effect of genotypes at each of the SNPs on the predicted breeding value for subcutaneous fat thickness was not statistically significant (P > 0.05). Reporter gene assays revealed no significant differences in gene expression between alleles at each of the SNPs. These findings suggest that EDG1 SNPs, although they may not be regarded as a causal mutation, may be useful for effective marker-assisted selection to increase the levels of marbling in Japanese Black beef cattle.