Structure and optical properties of ZnSeO alloys with O composition up to 6.4%

II–VI-O type alloy semiconductor ZnSeO (O composition up to 6.4%) is grown by molecular beam epitaxy. O composition increases with O₂ flow rate. Several XRD peaks are observed when O composition is 2–4%, indicating phase separation. Growth at low temperature results in higher O composition. Photoluminescence intensity of ZnSeO lattice matched to GaAs is much stronger than that of ZnSe and peak shifts to lower energies with increasing O composition. Photoreflectance spectroscopy is performed to investigate the band gap energy. The band gap energy investigated by photoreflectance decreases with increasing O composition due to large band gap bowing even when phase separation occurs. The bowing parameter is estimated as 8.4 eV.     

The multiple untranslated first exons and promoters system of the oestrogen receptor gene in the brain and peripheral tissues of the rat and monkey and the developing rat cerebral cortex

Recent studies on the human oestrogen receptor (ER) gene have revealed the complex system with the multiple untranslated first exons and promoters in the ER gene expression. Little information is however available on the system in the ER gene of the rat or nonhuman primate. The rat genomic library was first screened by the rat ER cDNA (0-1) probe. One of the four positive clones (lambda rEgE1) was subcloned and sequenced. The nucleotide sequence was found to contain the exon 0, the intron 0, and the exon 1 with its 3'-ends. The novel untranslated first exons, the exon ON and the exon OS, were further identified. These results indicated the presence of at least four subtypes of the rat ER mRNAs; the messages transcribed from promoter P-0 (ER mRNA (0-1)), putative promoter P-1 (ER mRNA (1-1)), promoter P-ON (ER mRNA (ON-1)) and promoter P-OS (ER mRNA (OS-1)). The P-O- or P-1 driven message (0-1) or (1-1) appeared to be expressed most strongly in major oestrogen central- (anterior pituitary, AP, hypothalamus-preoptic area, HPOA, and amygdala, AMG) and peripheral targets (uterus and ovary). The message (ON-1) was strongly expressed in the liver and kidney, but not in the HPOA, AMG, cerebral cortex, CC, and cerebellum, Ce. The OS-1 message was expressed variably but generally in the tissues examined except for the CC and Ce. Thus, the region- and tissue specific expression of the rat ER gene is likely to be regulated by the multiple untranslated exons and promoters system. Furthermore, when the ER mRNA subtypes were examined in the rat neonatal CC where the ER protein level rose transiently, considered as a model for the development of the ER or progestin receptor A and B isoforms, the expression of the ER mRNAs seemed to be differential postnatally, implicating some stage dependent usage of the promoters in the development. In the monkey, we identified the untranslated first exon OS, the homologue of the rat exon OS. Interestingly, the exon C was found to consist of two different exons, the exon OK and the exon OG. By the alternative usage of the promoters and the alternative splicing, at least six ER mRNA subtypes, that is, ER mRNAs (0-1), (1-1), (OS-1), (OS-OG-1), (OK-1) and (OK-OG-1) were identified in the monkey tissues. These messages were also differentially distributed in the monkey brain and other tissues. It was noteworthy that the P-OK driven messages were expressed almost exclusively in the monkey liver. These results have suggested that the systems of the multiple untranslated first exons and promoters and the alternative splicing are involved in the regulation of the region- and tissue specific expression of the ER gene in the brain and peripheral tissues of the rat and monkey. Stage-related usage of the promoters was also suggested in the ER gene expression in the CC of the postnatal rat in development.     

A Precomputed Approach for Real-Time Haptic Interaction with Fluids

The key to enhancing perception of the virtual world is improving mechanisms for interacting with that world. Through providing a sense of touch, haptic rendering is one such mechanism. Many methods efficiently display force between rigid objects, but to achieve a truly realistic virtual environment, haptic interaction with fluids is also essential. In the field of computational fluid dynamics, researchers have developed methods to numerically estimate the resistance due to fluids by solving complex partial differential equations, called the Navier-Stokes equations. However, their estimation techniques, although numerically accurate, are prohibitively time-consuming. This becomes a serious problem for haptic rendering, which requires a high frame rate. To address this issue, we developed a method for rapidly estimating and displaying forces acting on a rigid virtual object due to water. In this article, we provide an overview of our method together with its implementation and two applications: a lure-fishing simulator and a virtual canoe simulator     

Reduction in total surface area by the develpment of microdroplets during dewetting

To meet the demand of an increasing storage density, the lubricant film for the head disk interface (HDI) needs to be thinner and stronger. In recent years, a new head/disk system, such as the contact type, has been proposed. It is reported that PFPE Zdol coated on a magnetic disk is dewetted and microdroplets are formed due to polar interactions. This makes a flying magnetic head unstable, therefore, the physics and chemistry of the dewetting phenomenon are topics of current interest. We investigated the formation and development of microdroplets using an atomic force microscope (AFM) and an optical microscope. First, we observed the disk surface coated with PFPE Zdol by AFM. From the cross section images of the microdroplets, we found that the microdroplets had a shape similar to a sphere. With this finding, we estimated the contact angle of the microdroplets in each image. The results showed that the contact angle of the microdroplet gradually decreased with time, which indicated the existence of a PFPE thin film in the dewetted area. The thickness of the PFPE film in the dewetted area was then measured using an elliposometer. Next, we investigated the variation in the number and the average diameter of the microdroplets during dewetting using images observed by the optical microscope. The total surface area change was also calculated from the observed results, and it was found that the total surface area, namely the sum of the microdroplet surfaces and dewetted area, was reduced by the development of the microdroplets.     

Deposition of Si-DLC film and its microstructural, tribological and corrosion properties

Silicon-incorporated diamond-like carbon (Si-DLC) films were deposited using a bipolar-type plasma based ion implantation and deposition technique, and the effects of Si-incorporation on the microstructural, tribological, anti-corrosion and lubricant bonding properties of the Si-DLC films were investigated. The analysis of Raman spectroscopy exhibited that the sp³ bonds in the DLC film increase due to Si addition. XPS analysis revealed that a thick oxide layer exists on the Si-DLC film surfaces. These explain the high lubricant bonding properties of the Si-DLC films compared to that of the Si-free DLC films. The silicon oxide layer on the Si-DLC film and the transferred silicon oxide layer on the steel ball prevents from the metal/DLC contact between the Si-DLC film and steel ball when sliding, which results in a low friction. Incorporation of Si in DLC films led to significant improvements in the corrosion resistance due to low internal stress and thick insulating oxide layer.     

Effect of electrode surface roughness on breakdown conditioning under non-uniform electric field in vacuum

Breakdown (BD) characteristics in vacuum are strongly dependent on the electrode surface conditions, such as surface roughness. However, there is little known concerning the details of the relationship between the surface roughness and BD conditioning effect. In practical application, it is important to clarify how the surface roughness affects the breakdown conditioning characteristics, especially for the non-uniform field configuration. This paper discusses the effect of surface roughness on breakdown conditioning characteristics under non-uniform electric field in vacuum under applications of negative standard lightning impulse voltage. For this purpose, we examined the BD conditioning of a rod-to-plane electrode made of SUS304 and Cu-Cr. The surface roughness of R_a is controlled from 0.3 to 2.5 mum. Experimental results revealed that the enhancement of surface roughness of electrodes increases the number of BD to complete the conditioning effect. We explained the results from the observed results of the electrode surface. Consequently, we could clarify the effect of surface roughness on the conditioning effect under non-uniform electric field in vacuum quantitatively.     

Breakdown conditioning characteristics of long gap electrodes in a vacuum

An improvement in dielectric strength is required in vacuum circuit breakers (VCBs) intended for use in higher voltage systems. In order to develop higher voltage VCBs, it is important to improve the dielectric strength in a vacuum based on consideration of the vacuum breakdown mechanism. Particularly for gaps longer than 10 mm, little is known about the breakdown mechanisms and their quantitative analyses in a vacuum. This paper discusses the breakdown conditioning characteristics of long gap electrodes, under a non-uniform electric field in a vacuum. We treat gap lengths of up to 50 mm in this paper. The conditioning characteristics are investigated under impulse voltage applications. A negative standard lightning impulse voltage was applied to rod-plane electrodes made of Cu-Cr and SUS304 for different tip radii and gap distances until the conditioning effect was completed. We observed illumination spots on electrodes at each breakdown during the conditioning process and calculated the corresponding breakdown field strengths. Experimental results revealed that the tendency of breakdowns associated with long gaps is different from that for the short gaps. As a result, we clarified that the breakdown field strengths are nearly constant at 110-120 kV/mm at the distances longer than 10 mm, and the breakdown field strength is at its maximum when the gap distance is about 5 mm.     

A multi-objective discrete reliability optimization problem for dissimilar-unit standby systems

A new methodology for the reliability optimization of a k dissimilar-unit nonrepairable cold-standby redundant system is introduced in this paper. Each unit is composed of a number of independent components with generalized Erlang distributions of lifetimes arranged in a series–parallel configuration. We also propose an approximate technique to extend the model to the general types of nonconstant hazard functions. To evaluate the system reliability, we apply the shortest path technique in stochastic networks. The purchase cost of each component is assumed to be an increasing function of its expected lifetime. There are multiple component choices with different distribution parameters available for replacement with each component of the system. The objective of the reliability optimization problem is to select the best components, from the set of available components, to be placed in the standby system to minimize the initial purchase cost of the system, maximize the system mean time to failure, minimize the system variance of time to failure, and also maximize the system reliability at the mission time. The goal attainment method is used to solve a discrete time approximation of the original problem.      

Chronic pancreatitis, acute pancreatitis

MRCP has been recognized as a safe and noninvasive diagnostic method. In the present study we evaluated the usefulness of MRCP in diagnosis of chronic and acute pancreatitis. Two-dimensional fast asymmetric spin-echo (FASE) MRCP was performed in 40 patients with chronic pancreatitis and 13 with acute pancreatitis. In 29 patients (72.5%) with chronic pancreatitis and 9 (66.7%) with acute pancreatitis, main pancreatic duct (MPD) was visualized entirely. MRCP could demonstrate the characteristic findings of chronic pancreatitis such as dilatation and irregularity of MPD in most cases. In acute pancreatitis, MRCP indicated that MPD was normal in diameter, but irregular in configuration compared with that of the control group. MRCP may facilitate the diagnosis of chronic and acute pancreatitis.     

Preoperative predictors for organ-confined disease in Japanese patients with stage T1c prostate cancer

BACKGROUND: Little is known about the effects of long-term plateletpheresis on the donors' health. The aim of this study was to examine the effect of plateletpheresis on the time course of reticulated platelet counts as an estimate for thrombopoiesis. STUDY DESIGN AND METHODS: The effect of moderate platelet depletion on the thrombopoietic capacity was evaluated prospectively by the measurement of reticulated platelets before and after plateletpheresis and on the following 4 days. Donors undergoing plateletpheresis for the first time were compared to those donating platelets every other week for more than 18 months. RESULTS: The median levels of reticulated platelets were significantly lower in frequent donors than in new donors. In new donors, there was a transient increase in the median levels of reticulated platelets on Day 3 after apheresis, and baseline values were reached again on Day 4. On the contrary, in repeat donors, there was a sustained rise in the percentage of reticulated platelets from Days 1 through 4. However, this increase in reticulated platelet counts was still less than that seen in new donors. There was no difference in the peripheral blood platelet counts in the two groups at any time point. CONCLUSION: These findings suggest that repeat platelet donation might lead to a relative exhaustion of thrombopoiesis, as evidenced by the low levels of reticulated platelets exhibited by repeat donors. The reticulated platelet count can be used to monitor the thrombopoietic capacity of long-term platelet donors.