Search

This study proposes a method for analyzing magnetic devices such as inductors and wireless power transfer (WPT) systems based on a Cauer equivalent circuit. The circuit parameters are determined based on computed or measured input impedance. It is possible to obtain a dynamic response and eddy-current loss in the time domain for arbitrary drive voltage waveforms from the synthesized Cauer equivalent circuit. Magnetic saturation in the core of an inductor could be accurately represented using the Cauer circuit. Moreover, the transient response of a WPT device is shown to be modeled by the Cauer circuit, including the effect of misalignment.

Photoluminescence images and spectra of threading screw dislocations (TSDs) and threading edge dislocations (TEDs) were obtained and compared with synchrotron X-ray topography images. Discrimination between TSDs and TEDs by analysis of PL spot size in the imaging technique as well as PL spectra of the dislocations in a near infrared region is demonstrated. We also have succeeded in cross-sectional PL imaging of threading dislocations in a thick epilayer.

Defect formation during the ion implantation/annealing process in 4H-SiC epilayers is investigated by synchrotron reflection X-ray topography. The 4H-SiC epilayers are subjected to an activation annealing process after Aluminum ions being implanted in the epilayers. The formation modes of extended defects induced by the implantation/annealing process are classified into the migration of preexisting dislocations and the generation of new dislocations/stacking faults. The migration of preexisting basal plane dislocations (BPDs) takes place corresponding to the ion implantation interface or the epilayer/substrate interface. The generation of new dislocations/stacking faults is confirmed as the formation of Shockley faults near the surface of the epilayer and BPD half-loops in the epilayer.

The transfer and generation of extended defects in 4H-SiC epitaxial growth at a high growth rate are examined. An epilayer with virtually no basal plane dislocations (BPDs) is obtained using 4º off Si-face substrates, although the formation of 3C-polytype inclusions is occasionally observed. The behavior of BPDs and threading screw dislocations (TSDs) in epitaxial growth is also investigated by X-ray topography and transmission electron microscopy, and the propagation of BPDs and conversion and generation of TSDs in the epilayers are discussed.

Threading edge dislocations (TEDs) in a 4H-SiC epitaxial layer are investigated using high-resolution synchrotron topography. Six types of TED image are confirmed to correspond to the Burgers vector directions by a comparison of computer simulated images and observed topography images in crystal boundaries. Using a mapping method, a wide spatial distribution of the six types of TED is examined in a quarter section of a 2-inch wafer.

Defect formation in 4H-SiC(0001) and (000-1) epitaxy is investigated by grazing incidence synchrotron reflection X-ray topography and transmission electron microscopy. Frank-type faults, which are terminated by four Frank partials with a 1/4[0001] type Burgers vector with the same sign on four different basal planes, are confirmed to be formed by conversion of a 1c threading edge dislocation (TSD) in the substrate as well as simultaneous generation of a 1c TSD during epitaxy. The collation between the topography appearance and the microscopic structure and the variety of Frank faults are shown. Formation of carrot defects and threading dislocation clusters are also investigated.

Defect formation during the ion-implantation/annealing process in 4H-SiC epilayers is investigated by X-ray topography, KOH etching analysis and transmission electron microscopy. Nitrogen and phosphorus ions are implanted in the 4H-SiC epilayers and then activation annealing is performed at 1670 ºC. Linearly arrayed or clustered extended defects are found to be formed during the implantation/annealing process by comparing X-ray topography images taken before and after the process. It is confirmed that the defect arrays are formed underneath a shallow groove on the surface and consist of a high density of basal-plane Shockley-type stacking faults.

Synchrotron reflection X-ray topography and KOH etching were applied to investigate the effects of the ion implantation/annealing process on the existing dislocations in the 4H-SiC epilayers and second epitaxial growth on the ion implanted layer. No systematic generation of dislocations or stacking faults caused by the second epitaxial growth on the implanted layer was observed, while BPDs were confirmed to migrate in the epilayer during the implantation/annealing process. The BPDs bend markedly near the bottom of the implanted layer and tend to lie along the <1-100> (perpendicular to the off-cut direction) after the implantation/annealing process. The lattice mismatch strain created by the implantation is a possible driving force of the glide motion of the BPDs.

Background:It has been unclear whether psychological distress and prevalence of metabolic syndrome (MS) is associated independent of cardiorespiratory fitness and/or visceral fat area in patients with type 2 diabetes mellitus (type 2 DM).Methods:Ninety-seven newly diagnosed Japanese men with type 2 DM (aged 26–81) who did not receive any intervention or pharmacological therapy were divided into two groups of highly distressed (HD) and less distressed (LD) by the cutoff point of the General Health Questionnaire (GHQ). In addition, cardiorespiratory fitness (estimated oxygen uptake: O2max), visceral fat area (VFA), glucose and lipid metabolism, and resting blood pressure were assessed. MS was defined based on the criteria proposed by the World Health Organization (WHO). The odds-ratios (OR) for the frequency of a low level of fitness, extremely accumulated VFA, metabolic abnormalities, and MS in both groups were calculated using a logistic regression model.Results:The OR for the frequency of a low level of fitness, the top quartile of VFA, hyperinsulinemia, and MS were significantly higher in the HD than in the LD. The significantly high OR of hyperinsulinemia and MS in the HD disappeared after adjusting forO2max and/or VFA.Conclusions:Our study suggests that the association of psychological distress with hyperinsulinemia and MS might depend on cardiorespiratory fitness and/or VFA in Japanese men with type 2 DM.

Not Available

Preantral follicles mechanically isolated from the ovaries of 12-day-old mice were exposed to 2 mol ethylene glycol l(-1) for 2 or 5 min and then to a vitrification solution containing 6 mol ethylene glycol l(-1) and 0.3 mol raffinose l(-1) for 0.5, 1.0 or 2.0 min before vitrification. The vitrified and fresh preantral follicles were treated with collagenase, and the oocyte-granulosa cell complexes (OGCs) obtained were cultured in vitro for 10 days in membrane inserts. Preantral follicles exposed to 2 mol ethylene glycol l(-1) for 5 min and then to the vitrification solution for 0.5 or 1.0 min showed the highest survival rates after warming. The follicular loss after warming was approximately 20%. After in vitro culture, the proportion of viable OGCs from the vitrified follicles was 10% lower than that of the fresh preantral follicles. There were no differences in the rates of maturation, fertilization and subsequent development to blastocysts between the oocytes derived from vitrified follicles and those derived from fresh preantral follicles; however, the developmental competence of the oocytes derived from both vitrified and fresh preantral follicles grown in vitro was lower than that of oocytes grown in vivo. One of the five recipient mice that received 20 blastocysts derived from vitrified preantral follicles gave birth to six live pups. The results of the present study demonstrate for the first time that mouse preantral follicles can be vitrified and that some of the embryos derived from vitrified preantral follicles can develop to live pups.

Individuals may regard reproduction as optional but sufficient number of them must be productive to perpetuate the species. The reproductive system is surprisingly vulnerable and depends, among other things, on a limited endowment of oocytes, controlled proliferation of spermatogonial stem cells and the genetic integrity of both. The developmental competence of oocytes and spermatogonial stem cells is maintained by evolved mechanisms for cellular detoxification and genomic stability, and excess or damaged cells are eliminated by apoptosis. Gonadal failure as a result of germ cell depletion can occur at any age, and from the effects of chemical cytotoxicity, disease and infection as well as genetic predisposition. Among extrinsic factors, alkylating agents and ionizing radiation are important causes of iatrogenic gonadal failure in young women and men. In animal models, there is evidence that hormonal manipulation, deletion of genes involved in apoptotic pathways and dietary manipulation can protect against natural and induced germ cell loss, but evidence in humans is absent or unclear. Assisted reproductive technologies (ARTs) provide an ensemble of strategies for preserving fertility in patients and commercially valuable or endangered species. Semen cryopreservation was the first technology for preserving male fertility, but this cannot serve prepubertal boys, for whom banking of testicular biopsies may provide a future option. In sterilized rodents, cryopreserved spermatogonial stem cells can recolonize seminiferous tubules and reinitiate spermatogenesis, and subcutaneous implantation of intact tubules can generate spermatozoa for fertilization in vitro by intracytoplasmic sperm injection. Transplantation of frozen-banked ovarian tissue is well-established for restoring cyclicity and fertility and is currently undergoing clinical evaluation for cancer patients. When restoration of natural fertility is unnecessary or reimplantation is unsafe, it is desirable to culture the germ cells from thawed tissue in vitro until they reach the stage at which they can be fertilized. Low temperature banking of immature germ cells is potentially very versatile, but storage of embryos and, to a lesser extent, mature oocytes is already practised in a number of species, including humans, and is likely to remain a mainstay for fertility preservation.

The lowest triplet excited states of (2-substituted) 10-methylphenothiazine were found to be quenched by various electron acceptors in polar solvents such as 2-propanol and acetonitrile through electron transfer (ET). The transient absorption and time-resolved EPR spectra indicated that the radical cation of the phenothiazine and radical anions of the acceptors were formed as the ET products in moderate to high yields. These free radical ions were formed via two types of intermediates, (i) a triplet contact radical ion pair (³CRIP) or a triplet exciplex (³Ex*) and (ii) a triplet solvent-separated radical ion pair (³SSRIP). In the quenching by the Br-substituted acceptors, a large fraction of ³CRIP (or ³Ex*) was deactivated to the singlet ground states due to the breakdown of the spin-forbiddance by strong spin−orbit coupling. On the other hand, ³CRIP (or ³Ex*) containing no heavy atom was mainly transformed into ³SSRIP by solvation. ³SSRIP decayed through either the separation to free ions or the triplet−singlet conversion followed by the spin-allowed backward ET to the ground states. The backward ET rates of ¹SSRIPs were estimated to be ≥10⁹ s^-1, even when the reaction fell into the deeply inverted region. In 2-propanol, the free ion yields were affected by magnetic fields. The magnitudes of magnetically induced changes strongly depended on the polarity and viscosity of solvents, suggesting that the separation rate of SSRIP should be a crucial factor determining the field dependence of the free ion yields.

We investigated the effects of preexposure to ethylene glycol (EG) or raffinose on the viability of vitrified mouse oocytes. Ovulated oocytes at the metaphase II stage were preexposed either to 2 M EG for 0, 2, or 5 min or to ascending concentrations (0.15 followed by 0.3 M ) of raffinose solution for 2, 5, or 10 min each (here referred to as 2-2, 5-5, and 10-10 min, respectively). The oocytes were then exposed to a vitrification solution (VS), 6 M EG + 0.3 M raffinose, for 0.5, 1, 2, or 5 min and then vitrified or immediately diluted. After warming, the developmental capacity of oocytes was determined after in vitrofertilization. Volume changes in oocytes during preexposures and exposure to the VS were also investigated. The results demonstrated that preexposure to 2 M EG allowed shorter exposure times of oocytes to the VS and that predehydration in raffinose solutions for 5-5, but not 2-2 or 10-10 min, allowed a wider range of exposure times to the VS. Experiments on volume change suggested that the optimum time of exposure to the VS depends on the amount of EG permeation after preexposure to 2 M EG or to raffinose solutions. Preexposures to 2 M EG or raffinose under optimized conditions increased the viability of vitrified-warmed oocytes compared to direct exposure to VS without preexposures.

The effects of short-chain fatty acids (SCFA: acetate, propionate, and butyrate) on growth hormone (GH)-releasing hormone (GHRH)-induced GH secretion from pituitary somatotrophs were assessed on isolated anterior pituitary cells of goats. Cells were cultured in Dulbecco's modified Eagle's medium for 3 days, either in the presence (1, 3, or 10 mM) or in the absence of each SCFA, and then stimulated with GHRH (10−12to 10−7M) for 30 min, again in the presence of and at the concentration of SCFA used over the previous 3 days. In the cells cultured in the absence of SCFA, the addition of SCFA to the medium during the GHRH stimulation period did not significantly change GHRH-induced GH release. However, in cells cultured in the presence of either propionate (3 or 10 mM) or butyrate (1, 3, or 10 mM), the addition of SCFA to the medium during GHRH stimulation significantly reduced the GHRH-induced GH release. The inhibitory effects of SCFA were dependent on the concentrations of SCFA and were greater for butyrate than for propionate. In the cells cultured in the presence of butyrate, but not in the absence, the total GH production (the sum of the released GH and the remaining GH after stimulation) was also significantly reduced. The GHmRNA expression was reduced in the cells cultured with 10 mM butyrate, whereas it was enhanced by the stimulation with 10−7M GHRH. These findings suggest that propionate and butyrate may inhibit GHRH-induced GH release and GH production by caprine anterior pituitary cells.

Recently, we described a method to transplant testicular cells from a fertile donor mouse to the seminiferous tubules of an infertile recipient male, where the donor cells generate spermatogenesis. Spermatozoa produced by the transplanted cells in the recipient testis will fertilize eggs and transmit the donor haplotype to the resulting animals. In the most successful transplantations, up to 80 per cent of progeny sired by the recipient male arise from donor cell‐derived spermatozoa. The cell responsible for generation of spermatogenesis following transplantation clearly is a spermatogonial stem cell, since the repopulation of recipient testes extends for periods exceeding 12 months. In the past year, experiments have shown that rat testicular cells transplanted to the seminiferous tubules of immunodeficient mice will generate rat spermatogenesis and produce normal appearing rat spermatozoa, opening the possibility of xenogeneic testicular cell transplantation for other species. In addition, it has proved possible to cryopreserve spermatogonial stem cells for long periods, following which they will produce normal spermatogenesis when transplanted to a recipient. The ability to cryopreserve testicular stem cells makes individual male germ lines immortal. In current work, we are focusing on techniques to increase the efficiency of spermatogonial transplantation and methods to culture the stem cells.

Allyl chloride (ALL), acrylamide (ACR), and 2,5-hexanedione (2,5-HD) are all industrial neurotoxicants and known to produce accumulation of neurofilament (NF) proteins in both the central and peripheral nervous systems. To clarify whether any common mechanisms underlie these neurofilamentous axonopathies, the ability of ALL, ACR, and 2,5-HD to cross-link the NFs and the effects on NF degradation by Ca2+-activated neutral protease were investigated in spinal cords from rats subchronically treated with these chemicals. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis followed by immunoblot analysis revealed the appearance of high-molecular-weight species of NF triplets immunoreactive to each anti-68K, anti-160K, and anti-200K NF antibody in the 2,5-HD-treated rats, whereas it was not found in those treated with ALL or ACR. A time course study on the degradation of NF proteins conducted by the co-incubation with Ca2+showed degradation resistance in all three NF subunits from animals treated with 2,5-HD, while no significant alterations in the rate of NF degradation were observed in the ALL- or ACR-treated group. The present results suggest that neurofilament-filled axonopathy induced by ALL or ACR and axonopathy induced by 2,5-HD may not share a common mechanism, though the initial step for the pathogenesis of this chemically induced neurotoxicity is not fully understood at present.

In an attempt to utilize LaNiO3 as a bottom electrode for PbTiO3 ferroelectric film, PbTiO3 and LaNiO3 films were prepared by the spray-ICP technique under atmospheric pressure. The dense LaNiO3 films crystallized with preferred (1 1 1) and (1 0 0) orientations on sapphire (0 0 1) and MgO (1 0 0), respectively. Resistivities of the LaNiO3 films deposited above 600 °C were about 4 × 10-6 Om. The PbTiO3 film with preferred (001) orientation was successfully prepared on LaNiO3-coated MgO (1 0 0). Its dielectric constant and dissipation factor were about 200 and 0.02, respectively, at 1 kHz. The Curie temperature suggested that PbTiO3 films were free from contamination by LaNiO3.

PbTiO3 thin films were prepared on various substrates by spraying an ultrasonically atomized aqueous solution of Pb(NO3)2 + TiO (NO3)2 into an inductively coupled plasma (ICP) under atmospheric pressure. Single-phase PbTiO3 with perovskite structure was obtained at 500–650 °C. The perovskite obtained below 600 °C showed less tetragonality due to the effect of grain size. The PbTiO3 films crystallized with preferred (1 1 1) and (0 0 1) orientations on sapphire (0 0 1) and MgO (1 0 0), respectively. Based on the analysis of ICP emission spectra, it is suggested that a reoxidation of titanium preceded that of lead in the plasma, and also that OH in the plasma played an important role in the deposition of PbTiO3.

Spermatogenesis occurs within the seminiferous tubules of mammals by a complex process that is highly organized, extremely efficient and very productive. At the foundation of this process is the spermatogonial stem cell that is capable of both self-renewal and production of progeny cells, which undergo differentiation over a period of weeks to months in order to generate mature spermatozoa. It had been thought that germ cells survive only a brief period in culture, generally less than a few weeks. However, an accurate assessment of the presence of spermatogonial stem cells in any cell population has only recently become possible with development of the spermatogonial transplantation technique. Using this technique, we have demonstrated that mouse spermatogonial stem cells can be maintained in culture for approximately 4 months and will generate spermatogenesis following transplantation to the seminiferous tubules of an appropriate recipient. Extensive areas of cultured donor cell-derived spermatogenesis are generated in the host, and production of mature spermatozoa occurs Cultivation of the testis cells on STO feeders is beneficial to stem cell survival. These results provide the first step in establishing a system that will permit spermatogonial stem cells to be cultivated and their number increased in vitro to allow for genetic modification before transplantation to a recipient testis.

An observation of horizontal air showers of sizes from 103to 105particles (1 to 100 TeV in energy) has been performed. For showers of sizes up to ∼2.104, the size spectrum and zenith angle distributions are observed to be consistent with expectation. Some deviation appears in both the size spectrum and angle distributions for showers above ∼2.104, which suggests that they may be due to a short-lived muon parent particle.

The glucose transporter of human erythrocytes was reconstituted with soybean phospholipids by the freeze-thaw/sonication method and the distribution of the transporter molecules in liposomes was studied. The steady state level of glucose transport in reconstituted liposomes showed saturation when increased amounts of the transporter were used for reconstitution. The saturation curve fitted well to a theoretical curve which was derived assuming a Poisson distribution of the transporter. Freeze-fracture electron micrographs showed random distribution of intramembraneous particles on liposomes, irrespective of liposome size or amount of the transporter added. A detailed study showed a parameter of the distribution (the ratio of transporter to liposome) obtained from the transport measurement can be used for the analysis of the distribution of intramembraneous particles, indicating that most of the molecules seen as particles were active in transport.

The LaCuO3−yperovskite is considered as the first member of the 01(n−1)nseries of “layered cuprates.” Highly oxidized, stoichiometric LaCuO3is stabilized under very high oxygen pressures, and was synthesized in a cubic-anvil-type high-pressure apparatus at 5 GPa and 1400°C using excess amounts of KClO4as an external oxidizing agent. Upon heating under ambient pressure the rhombohedral high-pressure phase loses oxygen yielding tetragonal, monoclinic, and orthorhombic forms of LaCuO3−yas intermediate products before the final decomposition into La2CuO4and CuO or Cu2O around 800°C. All three oxygen-deficient LaCuO3−yphases could be isolated and their stability limits and corresponding oxygen contents conveniently investigated by annealing stoichiometric LaCuO3in a thermobalance of high sensitivity in order toin situdetect the exact amount of oxygen loss. The nominal copper valence values calculated from the oxygen contents are compared and discussed with XPS data as well as with the results evaluated from magnetic susceptibility measurements.

The aim was to determine the actual prevalence of liver disease and to investigate the contribution of various risk factors to liver disease among the population in a methyl mercury polluted area.

The 23-kDa form of prolactin (PRL) has been proposed to function as both a mature hormone and a prohormone precursor for different uniquely bioactive forms of the molecule. We have shown that the 16-kDa N-terminal fragment of PRL (16K PRL) inhibits angiogenesis via a specific receptor. In addition, 16K PRL stimulates natriuresis and diuresis in the rat, and kidney membranes contain high-affinity specific binding sites for this PRL fragment. 16K PRL can be derived from an enzymatically cleaved form of PRL (cleaved PRL). With the use of a specific 16K PRL antiserum, we have localized a 14-kDa immunoreactive protein in the paraventricular and supraoptic nuclei of the hypothalamus and in the neurohypophysis. Reverse transcription-polymerase chain reaction of RNA from isolated paraventricular nuclei showed the expression of the full-length PRL mRNA. The neurohypophysis was found to contain the enzymes that produce cleaved PRL, small amounts of PRL, and cleaved PRL. Medium conditioned by neurohypophyseal cultures, enriched with the 14-kDa immunoreactive protein, has antiangiogenic effects that are blocked by the 16K PRL antiserum. These results are consistent with the expression of PRL in the hypothalamic-neurohypophyseal system, and the preferential processing of the protein into a 14-kDa fragment with biological and immunological properties of 16K PRL.

The expression of mRNA encoding the long and short forms of the prolactin receptor (PRLR) in the fetal rat was examined using the method of reverse transcription-PCR. A 742 bp PCR product encoding the extracellular and transmembrane domains of the PRLR was detected in maternal and fetal liver and in fetal adrenal, kidney, small intestine, pancreas, brain, pituitary, thymus, lung and skin but not in fetal heart. Highest levels of the 742 bp PRLR transcript were detected in fetal adrenal (45·2% of levels in maternal liver), kidney (27·2%), small intestine (21·7%), pancreas (18·3%) and liver (10·8%), and tissue levels of the 742 bp product correlated positively (r=0·92, P<0·01) with the specific binding of the fetal lactogenic hormone rat placental lactogen II (rPL-II). These findings suggest that the PRLR may serve as a physiological binding protein for rPL-II in the rat fetus. There were striking differences in the relative expression of mRNA encoding the long and short forms of the PRLR. The long form of the receptor was expressed in maternal liver and placenta and in all fetal tissues studied except fetal heart. The short form of the receptor was also detected in maternal liver and placenta and fetal adrenal, kidney, small intestine, liver and thymus; in contrast, there was limited expression of the short-form of the receptor in fetal pancreas, pituitary and brain and no short form transcripts were detected in fetal lung, skin or heart. The results of these studies indicate widespread expression of the rat PRLR in fetal and uteroplacental tissues, implicating diverse roles for the placental prolactin-like proteins in fetal development.Journal of Endocrinology(1995) 144,285–292

Hyperplasia of myocytes in cardiac adaptation is a rare event in the mammalian cardiac muscle. Recent findings support the concept that proliferation of myocytes in the adult mammalian heart may be induced after a prolonged increase in pressure load on the myocardium. To determine whether short-term hypertension leads to hyperplasia of myocyte nuclei in the rat heart renal hypertension was produced in 12 Wistar rats. As soon as hypertension occurred, bromodeoxyuridine (BrdU) (50 mg/kg/day) was injected intraperitoneally on three subsequent days. Twelve sham-operated rats served as controls. After 3 days, the left cardiac ventricle was excised and double-staining with anti-BrdU antibody and propidium iodide was performed to determine the phase of cell-cycle of the BrdU-positive cells by flow-cytometry. Immunohistochemical double-staining with desmin, smooth muscle actin, vimentin, and BrdU was done to classify the BrdU-positive cells.