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An optimization method combining deep reinforcement learning (DRL) and computational fluid dynamics (CFD) was developed, and its effectiveness and limitations are investigated. As a target to apply the method, an optimization problem to find geometry parameters of the wavy airfoil that maximizes the lift–drag ratio is set. Twin delayed deep deterministic policy gradient (TD3) is adopted as the DRL algorithm. The CFD code based on the standard scheme for viscous incompressible flows is used for the calculation of the lift–drag ratio. The neural networks learn a policy for improving the lift–drag ratio by changing the geometry parameters of the airfoil at the fixed angle of attack (AoA) of 0° and successfully achieve a maximum lift–drag ratio: the obtained final shape is almost the same as that acquired by the gradient method. However, when the global optimal solution is near the penalized region, the DRL has the disadvantage of tending to fall into local optima. The effects of several parameters of DRL, such as the reward function and the number of sample points in random exploration, are investigated. Moreover, by using a trained neural network at an AoA of 0°, a converged solution can be obtained more quickly for an AoA different from those of the trained case if an appropriate reward function is set. This indicates the possibility of transfer learning. [ABSTRACT FROM AUTHOR]

We investigated photoresponses of AlGaAs solar cells in which coupled GaAs quantum wells were embedded in the i-region of p-i-n diodes; we studied how the bias voltage Vb affects the normal photocurrent I generated by the visible light and a "two-step" photocurrent ΔI generated by the absorption of visible and infrared photons. We found that as Vb exceeds -0.2 V, ΔI rises and peaks at 0.6 V, while the normal photocurrent I falls to about half ofits saturated level. These findings are discussed in terms of a rate equation model to show that ΔI is mainly determined by the balance of escape and recombination of photogenerated carriers. [ABSTRACT FROM AUTHOR]

We report the self-assembly of InAs ring complexes on InP (100) substrates by droplet epitaxy. Single-ring, ring-disk complex, and concentric double-ring structures were formed by controlling the As beam flux and substrate temperature. A clear photoluminescence signal was detected in a sample where InAs rings were embedded in InGaAs. [ABSTRACT FROM AUTHOR]

Correlation of evolution of end-of-range (EOR) damage and transient enhanced diffusion (TED) of indium has been studied by secondary ion mass spectrometry and transmission electron microscopy. A physically based model of diffusion and defect growth is applied to the indium diffusion system. Indium implantation with 200 keV, 1 X 10[sup 14]/cm² through a 10 nm screen oxide into <100> p-type Czochralski silicon wafer was performed. During postimplantation anneal at 750 °C for times ranging from 2 to 120 min, formation of dislocation loops and indium segregation into loops were observed. Simulation results of evolution of EOR defects show that there is a period that {311} defects dissolve and release free interstitials before the Ostwald ripening step of EOR dislocation loops. Our diffusion model that contains the interaction between indium and loops shows the indium pileup to the loops. Indium segregation to loops occurs at a pure growth step of loops and continues during the Ostwald ripening step. Although dislocation loops and indium segregation in the near-surface region are easily dissolved by high temperature annealing, EOR dislocation loops in the bulk region are rigid and well grown. It is considered that indium trapped by loops with a large radius is energetically stable. It is shown that modeling of the evolution of EOR defects is important for understanding indium TED. [ABSTRACT FROM AUTHOR]

Studies the transient enhanced diffusion of indium implanted in silicon in the presence of the end-of-range (EOR) damage layer. Transmission electron microscopy measurements and Rutherford backscattering spectrometry results; Deviation from the plus one model due to the mass effect of indium; Formation of extrinsic EOR dislocation loops.

Background: Spermatozoa become competent for fertilization during transit through the epididymis. As spermatozoa from the proximal caudal epididymis can fertilize eggs, proteins from the caput and corpus epididymis are required for sperm maturation. Objectives: Microarray analysis identified that more than 17,000 genes are expressed in the epididymis; however, few of these genes demonstrate expression restricted to the epididymis. To analyze epididymis‐enriched gene function in vivo, we generated knockout (KO) mutations in nine genes that are abundantly expressed in the caput and corpus region of the epididymis. Materials and methods: KO mice were generated using the CRISPR/Cas9 system. The histology of the epididymis was observed with hematoxylin and eosin staining. KO males were caged with wild‐type females for 3–6 months to check fertility. Results: We generated individual mutant mouse lines having indel mutations in Pate1, Pate2, or Pate3. We also deleted the coding regions of Clpsl2, Epp13, and Rnase13, independently. Finally, the 150 kb region encoding Gm1110, Glb1l2, and Glb1l3 was deleted to generate a triple KO mouse line. Histology of the epididymis and sperm morphology of all KO lines were comparable to control males. The females mated with these KO males delivered pups at comparable numbers as control males. Discussion and conclusion: We revealed that nine genes abundantly expressed in the caput and corpus epididymis are dispensable for sperm function and male fecundity. CRISPR/Cas9‐mediated KO mice generation accelerates the screening of epididymis‐enriched genes for potential functions in reproduction. [ABSTRACT FROM AUTHOR]

Presents a study that investigated the preparation of 90-K superconductor LaBa[sub2]Cu[sub3]O[suby] Details of the experiment; Experimental results; Discussion.

Abstract Background In Japan, 90% of kidney transplantations involve living related donors. A third-party interview is conducted during latter stages of preparation for transplantation to ensure the donor's voluntary decision-making. In this study, we investigated the factors responsible for withdrawal of decision for kidney donation by related living donors after third-party interview. Methods Related living donor candidates were divided into 2 groups based on their final decision: those who finally donated the kidney (FDG; n = 435); and those who withdrew their decision after third-party interview (WG; n = 11). The psychosocial and medical variables were compared and the reasons for withdrawal were investigated. Results Multiple logistic regression analysis revealed that none of the variables were significantly related to WG. Six categories of reasons for withdrawal were identified: "avoiding pregnancy risk"; "selecting alternative treatment"; "avoiding physical burden for donor"; "recipients' intemperance"; "need to take more time for decision-making"; and "psychological pressure." Conclusion A certain number of donor candidates withdrew their decision for different reasons, even in the latter stages of the transplant preparation. Careful verification of the donor candidates' individual situation and provision of adequate information and time are important to protect the donor's right to refuse. [ABSTRACT FROM AUTHOR]

SUMMARY: When a transformer is energized, inrush currents whose magnitudes may reach tens of its nominal current occur. Since the inrush currents lead to a voltage drop, this may cause stops and malfunctions of electrical appliances. In addition, the overcurrents may cause an unnecessary operation of an overcurrent relay and affect the power quality of the distribution system. Currently, distribution system operators use current‐versus‐time curves of transformer inrush currents for the studies of such phenomena. However, the studies based on the current‐versus‐time curve give approximate results, and studies based on the current‐versus‐flux curve is required so as to obtain accurate results. Considering this point, this report proposes a method to convert a given current‐versus‐time curve to a current‐versus‐flux one for the case of single‐phase transformers. Using the current‐versus‐flux curve obtained, detailed simulations can be performed using an electromagnetic transient analysis program such as XTAP. In this report, the proposed method is validated by experimental results using a single‐phase transformer. [ABSTRACT FROM AUTHOR]

We investigate the optical transitions of GaNxAs1-x quantum wells (QWs) embedded in wider band gap AlGaAs. A combination of absorption and emission spectroscopic techniques is employed to systematically investigate the properties of GaNAs QWs with N concentrations ranging from 0 - 3%. From measurement of the photocurrent spectra, we find that besides QW ground state and first excited transition, distinct increases in photocurrent generation are observed. Their origin can be explained by N-induced modifications in the density of states at higher energies above the QW ground state. Photoluminescence experiments reveal that peak position dependence with temperature changes with N concentration. The characteristic S-shaped dependence for low N concentrations of 0.5% changes with increasing N concentration where the low temperature red-shift of the S-shape gradually disappears. This change indicates a gradual transition from impurity picture, where localized N induced energy states are present, to alloying picture, where an impurity-band is formed. In the highest-N sample, photoluminescence emission shows remarkable temperature stability. This phenomenon is explained by the interplay of N-induced energy states and QW confined states. [ABSTRACT FROM AUTHOR]

We investigated the excitation power P dependence of photoluminescence (PL) spectra of GaSb type-II quantum dots (QDs) in GaAs grown by droplet epitaxy. We prepared two QD samples annealed at slightly different temperatures (380 °C and 400 °C) and carried out PL measurements. The 20 °C increase of the annealing temperature leads to (1) about 140 and 60 times stronger wetting layer (WL) luminescence at low and high P, (2) about 45% large energy shift of QD luminescence with P, and (3) the different P dependence of the PL intensity ratio between the QD and the WL. These differences of the PL characteristics are explained by the effects of the WL. [ABSTRACT FROM AUTHOR]

Abstract A 28-year-old woman was diagnosed as having an ectopic kidney in adolescence. She desired to donate her ectopic kidney to her mother, who was diagnosed as having renal failure. The ectopic kidney was located behind the sigmoid colon with 3 renal arteries and 3 renal veins. Laparoscopic donor nephrectomy was performed by reduced port surgery using the GelPOINT access platforms at a midline incision below the umbilicus with 1 accessory port. A thin artery of the donated kidney was ligated. An artery of the upper pole was anastomosed to the internal iliac artery, and a second artery was anastomosed directly to the inferior epigastric artery. Three veins were anastomosed to the external iliac vein: 1 anastomosed directly, 1 interposed by saphenous vein graft, and 1 interposed by harvested ovarian vein. To our knowledge, this is the first successful case of transplantation using an ectopic pelvic kidney by reduced port laparoscopic donor nephrectomy. Highlights • Laparoscopic donor nephrectomy of ectopic pelvic kidney was performed. • Operation was performed with reduced port procedure. • Complex vascular reconstruction was required. [ABSTRACT FROM AUTHOR]

Modification of starch blend properties by contact with supercritical carbon dioxide (scCO 2 ) was studied. Potato starch (PS), sweet potato starch (SPS), and cassava starch (CS) were blended with wheat starch (WS) at 15, 25, 50, 75 and 85% (w/w) ratios. For WS, the maximum decrease in gelatinization temperature ( T P ) was 13 °C. The WS–PS and WS–CS blends exhibited a decrease in T P of 13 to 17 °C. Reduction in T P by treatment was 10 to 18 °C for all blend ratios. Conditions for lowering the starch blend T P were determined to be a minimum contact time of 1 h with scCO 2 at 60 °C and 20 MPa. Swelling of starch granules that leads to the lowering of T P involves both kinetic and physicochemical factors. Gelatinization of wheat starch blends with scCO 2 pressure treatment provides a versatile and non-thermal method for modifying the properties of ingredients used in food processing applications. [ABSTRACT FROM AUTHOR]

Electromagnetic transient (EMT) simulations are now often used for system studies including power electronics converters which control voltages and currents using switching devices. The trapezoidal method, used in Electro-Magnetic Transients Program (EMTP) for numerical integration, produces "fictitious" sustained numerical oscillation, when an inductor current or a capacitor voltage is suddenly changed especially by switching. To cope with this problem, the research group of the authors has proposed applying the two-stage diagonally implicit Runge--Kutta (2S-DIRK) method which is an inherently "oscillation-free" numerical integration method. In order to bring out full accuracy of the 2S-DIRK method, supplementary numerical techniques are required for the representation of voltage sources, current sources and switches. This paper illustrates these techniques with numerical examples. [ABSTRACT FROM AUTHOR]

We have fabricated GaAs/AlGaAs quantum well (QW) solar cells in which 3 nm-thick QWs and indirect-gap Al0.78Ga0.22As barriers are embedded, and we studied extraction processes of photogenerated carriers in this QW system. The photocurrent under 700 nm light illumination at voltages close to the open-circuit voltage shows only a small reduction, indicating that the carrier recombination inside QWs is largely suppressed. We attribute this result to an efficient extraction of electrons from the QWs through the X-valley of AlGaAs. The insertion of QWs is shown to be effective in extending the absorption wavelengths and in enhancing the photocurrent. The use of indirect-gap materials as barriers is found to enhance carrier extraction processes, and result in an improved performance of QW solar cells. [ABSTRACT FROM AUTHOR]

Accessible summary Consumer gender and age, and nurse gender influenced the perception of overall severity of aggressive incidents, in addition to the aggression data provided by the Staff Observation Aggression Scale - Revised (SOAS-R) scores., The factors influencing assessments of aggression incident severity can be identified from the severity scores provided by concurrently conducting objective (i.e. SOAS-R) and overall (i.e. visual analogue scale) assessments., Abstract The aim of this study is to investigate factors associated with overall judgements of aggression severity as provided by ward nurses, using the Japanese-language version of the Staff Observation Aggression Scale - Revised (SOAS-R). Nurses who observed 326 aggressive incidents involving psychiatric inpatients at five mental health facilities in Japan provided their assessments of the incident severity both on the established rating scale, the SOAS-R, and on a visual analogue scale (VAS), a one-item scale to indicate overall aggression severity. To evaluate the factors influencing the VAS severity scores, a multiple regression analysis was performed, in which consumer, nurse and ward characteristics were added consecutively, along with SOAS-R severity scores as independent variables. SOAS-R scores explained 17.6% of the VAS severity scores. Independently from the SOAS-R scores, the gender and age of the aggressive consumers (adjusted R2= 10.0%), as well as the gender of the nurses who reported the aggression (adjusted R2= 4.1%), each explained VAS severity score to a significant degree. Apart from the SOAS-R scores, consumer and nurse characteristics appeared to influence the overall judgements of severity of aggressive incidents, which may be connected to decisions about the use of coercive measures, such as seclusion/restraint or forced medication. [ABSTRACT FROM AUTHOR]

The authors investigated influence of repeated and non-repeated c-axis tensile stresses on critical currents and AC transport losses in multi-filamentary Bi2223/Ag-sheathed tape wires reinforced by copper alloy tapes. Experimental results show that characteristics of the AC transport losses change and the manners of the changes are classified into three patterns, when the critical currents are degraded by the stresses. Features of defects caused in superconducting filaments by the stresses are discussed in relation to the three patterns of the transport loss characteristics. [ABSTRACT FROM PUBLISHER]

Abstract: It is necessary to obtain basic information on transcription factors expressed in the spermatids of livestock to determine mechanisms of defective spermiogenesis. In this study, we characterized the activator cAMP responsive element modulator (CREM) ortholog isoforms in porcine testicular germ cells and ejaculated sperm. At least two kinds of porcine activator CREM τ family ortholog mRNAs were more strongly expressed in the testis than in kidney or liver. The activator CREM isoform ortholog proteins were localized in nuclei of round spermatids and around nuclei of elongated spermatids. Furthermore, approximately 34% of ejaculated sperm had the activator CREM isoform ortholog proteins at their connecting piece. This is apparently the first report demonstrating the expression and localization of the activator CREM isoform ortholog proteins in spermatids and ejaculated sperm of a livestock species. [Copyright &y& Elsevier]

We report on the fabrication of a lattice-matched GaAs/AlGaAs quantum dot solar cell (QDSC) in which a ten-stacked QD layer is embedded. The GaAs QDs were grown by droplet epitaxy. Photocurrent originating from the QDs was confirmed. Cross-sectional scanning transmission electron microscopy (TEM) revealed no apparent dislocation in the QD layers. [ABSTRACT FROM AUTHOR]

We investigated effects of the antimony flux on GaSb quantum dots (QDs) formed by droplet epitaxy. Ga droplets were first formed on GaAs and exposed to Sb4 molecular beam at 200 °C, where the flux PSb of Sb beam was varied from 2.4 to 12.8 × 10-7 Torr. The samples were then annealed for 2 minutes under the Sb flux. An atomic microscope study showed that the diameter of GaSb QDs increases and the density decreases, as the Sb flux PSb is increased. This indicates that the coalescence process of GaSb QDs occurs and is accelerated by the increase of the Sb flux. In a photoluminescence (PL) study, we observed a broad peak of GaSb QDs in all samples, while a strong luminescence of a wetting layer (WL)-like structure was found only in the samples prepared with the high Sb flux. This suggests that the PL of WL is controllable by adjusting the flux PSb of Sb beam. [ABSTRACT FROM AUTHOR]

Abstract: Thermodynamic evaluation of Cu–Cu3P system has been conducted by applying subregular solution model with Gibbs energy of Cu3P formation that was newly determined by means of triple Knudsen cell mass spectrometry. Both the calculated vapor pressure of phosphorus and phase diagram of Cu–P system are excellently consistent with the literature data in the composition range of Cu–Cu3P, indicating that there is no significant thermodynamic inconsistency between the present work based on the Gibbs energy of Cu3P formation determined and the literature data. [Copyright &y& Elsevier]

Autophagy is a catabolic cellular process involving dynamic membrane rearrangement. Here, we review the understanding of autophagy, focusing on the late stages of the process, from the closing of the autophagosome to fusion with the lysosome. We propose the Reverse fusion model, for the closing autophagosome. In this model, autophagosome closure proceeds in a topologically similar but reverse order to membrane fusion during the escape of influenza virus from the endosome. This dynamic process is thought to be directly catalyzed by LC3, an ubiquitin-like molecule. Further, we discuss the dynamics of the Atg16L complex in relation to the LC3 localization in these processes. Finally, the molecular mechanisms involved in the delivery of autophagosomes to the lysosome and fusion are introduced. Several key events exist in each step and seem to be coordinated to faithfully conduct the autophagic process.Cell Death and Differentiation (2009) 16, 984–990; doi:10.1038/cdd.2009.54; published online 8 May 2009 [ABSTRACT FROM AUTHOR]

Type I IFN receptor type 2 (IFNAR2) expression correlates significantly with clinical response to interferon (IFN)-alpha/5-fluorouracil (5-FU) combination therapy for hepatocellular carcinoma (HCC). However, some IFNAR2-positive patients show no response to the therapy. This result suggests the possibility of other factors, which would be responsible for resistance to IFN-alpha/5-FU therapy. The aim of this study was to examine the mechanism of anti-proliferative effects of IFN-alpha/5-FU therapy and search for a biological marker of chemoresistance to such therapy. Gene expression profiling and molecular network analysis were used in the analysis of non-responders and responders with IFNAR2-positive HCC. The Wnt/beta-catenin signalling pathway contributed to resistance to IFN-alpha/5-FU therapy. Immunohistochemical analysis showed positive epithelial cell adhesion molecule (Ep-CAM) expression, the target molecule of Wnt/beta-catenin signalling, only in non-responders. In vitro studies showed that activation of Wnt/beta-catenin signalling by glycogen synthesis kinase-3 inhibitor (6-bromoindirubin-3'-oxime (BIO)) induced chemoresistance to IFN-alpha/5-FU. BrdU-based cell proliferation ELISA and cell cycle analysis showed that concurrent addition of BIO and IFN-alpha/5-FU significantly to hepatoma cell cultures reduced the inhibitory effects of the latter two on DNA synthesis and accumulation of cells in the S-phase. The results indicate that activation of Wnt/beta-catenin signalling pathway induces chemoresistance to IFN-alpha/5-FU therapy and suggest that Ep-CAM is a potentially useful marker for resistance to such therapy, especially in IFNAR2-positive cases. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the results of the experimental and analytical studies undertaken for the lightning protection of wind turbine generator systems by using a reduced-size wind turbine model. In the analytical studies, the FDTD (Finite Difference Time Domain) method is used. This study focuses on the overvoltages observed at the wavefronts of lightning surges. The lightning strokes on one of the blades and on the nacelle were considered, and the experiments and analyses were carried out by considering the cases of summer and winter lightning. The voltages and currents at various positions on the wind turbine model were considered. [Copyright &y& Elsevier]

Abstract: The enzymatic digestibilities of raw and gelatinized starches in various potato starches, as well as sweet potato, cassava, and yam starches, were estimated, along with other starch properties, such as the phosphorus content, median granule size, and rapid visco analyzer (RVA) pasting properties. Furthermore, correlation coefficients were calculated between the hydrolysis rates (HR) by amylase and other starch quality parameters. A larger granule size was closely associated with a lower HR in raw starch, while the HR in gelatinized starch did not correlate with the median granule size. An increase in phosphorus content resulted in a definitely lower HR in raw starch and tended to decrease the HR in gelatinized starch for the composite of potato and other starches. In contrast, no correlation coefficients of the phosphorus content with the HRs in raw and gelatinized starches were observed within potato starches. Starches with higher peak viscosity and breakdown showed a lower HR in raw starch, while few or no effects of these RVA parameters on the HR in gelatinized starch were observed for the composite of potato and other starches or among potato starches, respectively. [Copyright &y& Elsevier]

The porcine MX1 and MX2 promoters were characterized in this study. Sequencing of the 332-bp MX1 promoter region identified 15 substitutions and insertions at three positions in 21 pigs from 15 breeds, in which nine genotypes were classified. Among the nine genotypes, no statistically significant differences in the promoter activities were observed after interferon (IFN- α 2b) treatment of transiently transfected cells containing constructs with luciferase reporter plasmids. The 341-bp MX2 promoter region contained regulatory sequences for ISRE, GC box, Sp1 and AP-1, as well as a TATA box. Nucleotide sequences of the MX2 promoter region revealed four substitutions and one deletion, in which six genotypes were classified. Among the six genotypes, a statistically significant difference ( P < 0.05) in MX2 promoter activities after IFN- α 2b treatment was detected in transiently transfected cells. [ABSTRACT FROM AUTHOR]

Differential scanning calorimetry (DSC), acidic hydrolysis and different physico-chemical approaches were used to study thermodynamic and structural characteristics of starches from near-isogenic wheat lines to establish the effect of different combinations of active granule-bound starch synthase isoforms, taking part in amylose biosynthesis, on the structure and thermodynamic properties of starches. Obtained results suggest that the effect of different GBSS I combinations is realized through altered amylose localization within starch granules, reflecting in changes of melting temperature of crystalline lamellae ( T m) and rates of acidic hydrolysis. It has also been demonstrated that changes in T m values for native wheat starches are determined by amylose content in amylopectin clusters. [ABSTRACT FROM AUTHOR]

Abstract: We demonstrate self-assembly of GaAs double quantum dots (DQDs) by droplet epitaxy in a lattice-matched system in addition to concentric quantum double rings (CQDRs). The growth mechanism of these complex nanostructures is understood by taking into account the two crystallization processes; the counter-migration (of Ga and As atoms)-induced crystallization and droplet-edge-enhanced crystallization. By tuning the balance between these two processes, completely different types of the coupled quantum nanostructures are created. [Copyright &y& Elsevier]

Abstract: We report current–voltage (I–V) characteristics in GaAs/AlGaAs double-barrier resonant tunneling diodes (DB-RTDs), in which GaAs quantum rings (QRs) that are grown on a 4-nm thick GaAs are sandwiched between AlGaAs barrier layers. The QRs prepared by droplet epitaxy are 40nm wide and 4nm high. Negative differential resistance (NDR) and asymmetric resonance feature are observed in the QR-embedded RTDs. From comparison with references, we conclude that the NDR feature is originated from the 4-nm thick QW, not QRs. [Copyright &y& Elsevier]

Abstract: The induced activity, radiation damage, and compositional change of several superconductor materials, such as Nb-based alloys, V-based alloys, and MgB2, for the toroidal field (TF) and central solenoid (CS) magnets of a tokamak-type fusion reactor have been evaluated under the first wall neutron loading of 1MW/m2 with a numerical calculation. The damage rates of both Nb- and V-based alloys calculated are about (1–3)×10−4 dpa/y at the TF coils adjacent to the vacuum vessel and (2–6)×10−7 dpa/y at the surface of CS coil. The damage rate of MgB2 is about 1 order magnitude higher than those of Nb- and V-based superconducting materials. Most of the induced activity of V-based alloys and MgB2 after shutdown of the reactor is controlled by 60Co formed from Cu. Nb-based alloys are predicted to emit gamma rays for tens of thousands years due to 94Nb from Nb. In the case of the CS coils, the formation of 94Nb is minimal, and the gamma ray decay of Nb-based alloys is expected to be faster than that of V-based alloys. [Copyright &y& Elsevier]

Abstract: InGaAs and GaAs layers and GaAs/AlAs superlattice (SL) structures were grown by MBE on (757)B GaAs substrates and their corrugated growth fronts induced by the step bunching process were closely investigated by scanning transmission electron microscope (STEM). Cross-sectional images obtained from the direction have revealed asymmetries and other features of strongly corrugated InGaAs layers and a smoothing process in GaAs/AlAs SL layers. [Copyright &y& Elsevier]

Abstract: Long Si nanowires were tried to form using a thermal gradient evaporation method. Amorphous SiO2/Si nanowires longer than 6mm were formed at 1403–1433K. The long nanowires consist of a silicon single core of 50–100nm in diameter and an amorphous SiO2 outer layer of 10–15nm in thickness. The growth direction of the long Si nanowires was 〈111〉. The nanowires showed IR absorption peaks at 1130, 1160 and 1200cm-1 due to the disordered structure of SiO2/Si nanowires. [Copyright &y& Elsevier]

The induced activity and compositional change of several superconducting materials such as Nb-based alloys, V-based alloys and MgB2 have been evaluated with a numerical calculation. We assume that the materials are irradiated for 10 MW a/m2 at the magnet of the inboard position of a tokamak-type fusion reactor with a neutron wall loading of 1 MW/m2. The materials are Nb3Sn, Nb3Al, NbTi, NbZr, V2Zr, V2(Zr,Hf), V3Ga, V3Si and MgB2. Most of the induced activity of V-based alloys and MgB2 after the shutdown of the reactor is controlled by the 60Co formed from Cu. After the irradiation, the dose rate decreases to a safe level of 10 μSv/h within 30 years. However, Nb-based alloys are predicted to emit gamma rays for tens of thousands years. The compositional changes and irradiation damage of V-based alloys and MgB2 are minimal. [Copyright &y& Elsevier]

Inelastic scattering processes of the two-dimensional electron gas (2DEG) in both normal and inverted n-AlGaAs/GaAs heterojunction FET structures have been studied, for the case where InGaAs dots are embedded in the vicinity of GaAs channel. By analyzing the magnetoresistance data, the inelastic scattering time τin is determined as a function of the concentration N2D of 2D electrons and shown to be reduced by 10–40% by the presence of InGaAs dots. By investigating a GaAs/n-AlGaAs inverted heterojunction FET with embedded InGaAs dots, we have varied the percentage Poc of charged dots filled with an electron and found that τin decreases as Poc increases, indicating that the inelastic scattering rate of 2DEG by charged dots is higher than that by the neutral ones. [Copyright &y& Elsevier]

The relation between the critical current density and flux flow resistivity in a Bi2223 bulk for fault current limiter was experimentally investigated. The distributions of J[sub c] and voltage along the longitudinal direction were measured as well as transport current. As a result, it is found that the flux flow resistivity is the higher of at the position with lower critical current. Measured results was numerically analyzed to obtain the empirical expression for the flux flow resistivity as a function of the critical current density, accumulated Joule heat and transport current. [ABSTRACT FROM AUTHOR]

The AC transport current loss generated in a Bi2223 straight bulk having circular cross section and infinite length was calculated by one-dimensional analysis, assuming that the electric field–current density (E–J) characteristic of the bulk depends on the magnetic field. First, we estimated the loss of the sample conductor made by us. When the transport current whose peak value equal to critical current flows, the loss of 1.52×10−3 J/m is generated per cycle. The temperature rise due to the loss is very small and hardly causes the critical current degradation. This magnitude of the loss is a little larger than that of YBCO thin films having almost the same critical current as the bulk. In the case that the fault current limiter made from the bulk is installed into a 6.6 kV distribution system, the total AC transport current loss is less than 1/100 of transmission loss in the distribution system. [Copyright &y& Elsevier]

The AC transport current loss generated in a Bi2223 straight bulk having circular cross section and infinite length was calculated by one-dimensional analysis, assuming that the electric field–current density (E–J) characteristic of the bulk depends on the magnetic field. First, we estimated the loss of the sample conductor made by us. When the transport current whose peak value equal to critical current flows, the loss of 1.52×10−3 J/m is generated per cycle. The temperature rise due to the loss is very small and hardly causes the critical current degradation. This magnitude of the loss is a little larger than that of YBCO thin films having almost the same critical current as the bulk. In the case that the fault current limiter made from the bulk is installed into a 6.6 kV distribution system, the total AC transport current loss is less than 1/100 of transmission loss in the distribution system. [ABSTRACT FROM AUTHOR]

Abstract. Previous studies have shown that intracellular glutathione, a ubiquitous intracellular thiol, is related to cell proliferation and that cysteine or its disulphide form, cystine, also induces cell proliferation. Cysteine is a thiol containing amino acid and a rate-limiting precursor of glutathione. Therefore, it is still unresolved as to whether the proliferative effect of cysteine or cystine is entirely mediated by a change in the intracellular glutathione status. The objective of this study was to delineate the relationship among cysteine/cystine (thereafter referred to as cyst(e)ine), intracellular glutathione and cell proliferation in the human colon cancer CaCo-2 cell line. CaCo-2 cells were cultured in cyst(e)ine-free Dulbecco’s Modified Eagle Medium without serum, and treated with 200 µm cysteine and/or 200–400 µm cystine for 24 h. In the presence of DL-buthionine-[S, R]-sulfoximine (BSO), a glutathione synthesis inhibitor, exogenously administered cyst(e)ine did not change the intracellular glutathione content, but increased the intracellular cysteine as well as cystine level. Addition of exogenous cyst(e)ine following 5 mm BSO treatment significantly increased cell proliferation as measured by 3 H-thymidine incorporation and protein content. Cell cycle analyses revealed that cyst(e)ine promoted cell progression from the G1 phase to the S phase. Correspondingly, cyst(e)ine treatment induced expression of cyclin D1 and phosphorylation of retinoblastoma protein (Rb). In conclusion, these data indicate that both cysteine and cystine have proliferative effects in CaCo-2 cells independent of an increase in intracellular glutathione. Induction of cyclin D1, phosphorylation of Rb, and subsequent facilitation of G1 -to-S phase transition were involved in the proliferative effect of exogenous cyst(e)ine. [ABSTRACT FROM AUTHOR]

We have grown InGaAs quantum wells (QWs) with quasi-periodic interface corrugation on (1 1 1)B misoriented GaAs substrates and studied their transport and optical properties. By atomic force microscopy the corrugation is found to be multiatomic steps of about 30 nm in period and 2 nm in height which lie along the 〈1 0−1〉 direction. Electron mobilities μ across the steps at 4.2 K depend strongly on the electron concentration Ns, being proportional to Ns3.3, and are far smaller than μ along the steps by a factor of 5–10. By comparing these data with theory, μ–Ns characteristics are roughly explained by taking into account both periodic and random scattering components of interface corrugation. Optical properties of a QW with corrugation are also discussed. [Copyright &y& Elsevier]

Investigates the critical current and the transient change of resistance in a Bi2223 bulk applied direct current magnetic field. Estimation of the condition under which the gross resistance of the bulk rises while maintaining the critical current and bulk volume; Bulk volume required to obtain the critical current and resistance designated.

Presents further improvements of a phase-domain Auto-Regressive Moving Average (ARMA) line model in terms of convolution, steady-state initialization, and stability. Implementation of the model; What improvement to convolution indicates; Purpose of use of linear interpolation; Development of steady-state initialization model and fault-surge calculation; Presentation of convenient stability criteria of line model.

Abstract: We fabricated InAs nanoscale rings on InP substrates by droplet epitaxy. The rings were formed on an InGaAs layer with a thickness of d (d=0, 3, 4, and 10nm), below which a 10-nm-thick InAlAs layer was deposited. While the ring was closed when d=10nm, it was of C-shape when d=3 and 4nm. Furthermore, in the former ring, a 10-nm deep hole was formed at its center and, in the latter ring, the depth of the hole was only 3 to 4nm. The change in the ring shape is discussed in terms of behaviors of In droplets during crystallization. Photoluminescence (PL) originating from the nanoscale rings was observed. [Copyright &y& Elsevier]

Abstract: We examine in detail the spontaneous formation process of a cluster of InAs dots on GaAs (100) by droplet epitaxy. A cluster of dots was fabricated by irradiating an As flux for 30s to In droplets. The dots were found to be formed mainly along a ring-like zone stretching in the [011] direction, showing that In atoms migrated from the droplet and reacted with As atoms. This indicates the presence of not only the surface diffusion of In atoms but also the inward diffusion of As atoms. This is supported by the fact that such a ring was not visible when the As irradiation time was shortened (5s). For photoluminescence measurements the dots were capped with a 50-nm-thick GaAs layer. Two peaks at 1.46 and 1.3eV were observed in the sample annealed at 750°C. These peaks were attributed to the wetting layer and the dots, respectively. [Copyright &y& Elsevier]

Abstract: Nanometer-scale Al particles are fabricated and are embedded in a GaAs matrix using molecular beam epitaxial technique. The Al particle is self-assembled on GaAs by supplying an Al molecular beam. The average particle size is found to be 25nm. The density is 7×1010 cm−2 when Al of 6.2×1015 atoms/cm2 is supplied on (100)GaAs at a substrate temperature of 300°C. Clear hysteresis and plateaus in capacitance–voltage (C–V) curves are found in an Al-embedded sample, whereas monotonic increase of capacitance is obtained in a reference sample having an AlAs layer instead of Al. This difference results from trapping of electrons by the Al particles, suggesting that the particles have metallic character. [Copyright &y& Elsevier]

We have studied the correlation length (Λ) of interface roughness in GaAs/AlAs quantum wells (QWs) prepared by molecular beam epitaxy (MBE). It is found that the mobility of two-dimensional electrons in very thin selectively doped GaAs/AlAs QW structures is substantially enhanced when the bottom AlAs barrier layer is prepared by alternate beam MBE and/or by the use of superlattice buffer layer below the QW. By measuring the electron concentration dependence of mobility and comparing with the theory of interface roughness scattering, we have found that Λ of the bottom (GaAs-on-AlAs) interface of the QW gets as large as 200–300 Å, when prepared by the modified growth technique, which is about three times as large as that (∼70 Å) by conventional MBE. [ABSTRACT FROM AUTHOR]

We study experimentally and theoretically the influence of interface roughness on the mobility of two-dimensional electrons in modulation-doped AlAs/GaAs quantum wells. It is shown that interface roughness scattering is the dominant scattering mechanism in thin quantum wells with a well thickness Lw<60 Å, where electron mobilities are proportional to L6w, reaching 2×103 cm2/V s at Lw∼55 Å. From detailed comparison between theory and experiment, it is determined that the ‘‘GaAs-on-AlAs’’ interface grown by molecular beam epitaxy has a roughness with the height of 3–5 Å and a lateral size of 50–70 Å. [ABSTRACT FROM AUTHOR]

Cluster ions of alloys (Li-Na, Li-Mg) have been produced by a liquid metal ion source (LMIS), and analyzed by mass spectrometry. For the Li-Na system, bimetallic clusters with various compositions were formed, and dominant bimetallic species were NaLi, NaLi, NaLi and NaLi with this sequence of ion intensity. These clusters are systems containing 2 or 8 valence electrons except for NaLi. For the Li-Mg, observed bimetallic clusters were limited to only three species (MgLi, MgLi and MgLi), but unexpectedly small multiply charged homonuclear clusters, Mg and Mg, were observed. [ABSTRACT FROM AUTHOR]

Cluster abundance of Li ( n≤19), Na ( n≤25), Si ( n≤8 for z=1, 3≤ n≤7 for z=2), Ge ( n≤11 for z=1, 3≤ n≤9 for z=2, n=4 for z=3), Sn ( n≤7 for z=1, 3≤ n≤9 for z=2, n=4 for z=3) and Pb ( n≤6 for z=1, 5≤ n≤7 for z=2) ejected from a liquid metal ion source has been investigated by mass spectrometry. The abundance spectra of alkali metal clusters showed distinct maxima and steps at n=3, 7, 9, 13 and 19 for Li, and at n=3, 5, 11, 13 and 19 for Na. Mass spectra of Si, Ge and Sn clusters were very similar each other, showing intensity drops after n=4 and 6 (and also n=10 for Ge) for singly charged clusters. The magic numbers observed are discussed in terms of stability of charged clusters. [ABSTRACT FROM AUTHOR]