Showing papers by "Hiroki Kondo published in 2014"

Carbon nanowall scaffold to control culturing of cervical cancer cells

Abstract: The effect of carbon nanowalls (CNWs) on the culturing rate and morphological control of cervical cancer cells (HeLa cells) was investigated. CNWs with different densities were grown using plasma-enhanced chemical vapor deposition and subjected to post-growth plasma treatment for modification of the surface terminations. Although the surface wettability of the CNWs was not significantly dependent on the CNW densities, the cell culturing rates were significantly dependent. Morphological changes of the cells were not significantly dependent on the density of CNWs. These results indicate that plasma-induced surface morphology and chemical terminations enable nanobio applications using carbon nanomaterials.

Chemical reactions during plasma-enhanced atomic layer deposition of SiO2films employing aminosilane and O2/Ar plasma at 50 °C

Abstract: We report the temporal evolution of surface species observed in situ using attenuated total reflection Fourier transform infrared absorption spectroscopy (ATR-FTIR) during plasma-enhanced atomic layer deposition (PE-ALD) of SiO2 films employing aminosilane and an O2/Ar plasma at a temperature of 50 °C. Reversals in the appearance of IR absorbance features associated with SiO–H, C–Hx, and Si–H proved to coincide with the self-limiting reaction property in ALD. Our IR results indicate that an O2/Ar plasma can both removed CHx groups and transform SiH surface species to SiOH. In addition, SiO2 deposition was confirmed by a continuous increase in Si–O absorbance with each PE-ALD step, which becomes stable after several cycles. On the basis of our results, the mechanism of low temperature SiO2 PE-ALD was discussed.

Vehicle, control apparatus for vehicle, and control method for vehicle

Abstract: In engaging (connecting) a dog clutch by operating a synchromesh mechanism, when there occurs an uplock at the time when a first pressing force is caused to act on a hub sleeve, tooth tips of spline teeth of the hub sleeve contact with tooth tips of spline teeth of a synchronizer ring, and these spline teeth cannot be engaged. However, when a second pressing force is caused to act on the hub sleeve, the uplock is easy to be released. In addition, when torque from an engine is caused to act on the hub sleeve, a displacement is caused to occur in a rotation direction between the mutually contacting spline teeth. Thus, the uplock is reliably released.

A CMOS sensor platform with 1.2 µm × 2.05 µm electroless-plated 1024 × 1024 microelectrode array for high-sensitivity rapid direct bacteria counting

Abstract: A CMOS sensor platform with a bacteria-sized (1.2 μm × 2.05 μm) Au electroless-plated 1024 × 1024 microelectrode array for high-sensitivity rapid direct bacteria counting is demonstrated. For high-sensitivity direct pathogen counting, Au microelectrodes are required to be as small as the target cell. In this work, by improving a self-aligned electroless plating technique, the size of microelectrodes on a CMOS sensor chip was successfully reduced to 1.2 μm × 2.05 μm, corresponding to 1/20th of the smallest size reported in literature. Two test chips with 1024 × 1024 and 32 × 32 sensor arrays were fabricated in a 0.6-μm CMOS process and microelectrodes were formed on them using electroless plating. The uniformity among the 1024 × 1024 electrodes arranged with a pitch of 3.6 μm × 4.45 μm was optically verified. In addition, the trenches on each microelectrodes for improving sensitivity were developed and optically verified for the first time. Cyclic voltammetry (CV) measurements made using the 32 × 32 sensor array chip with 6-μm square electroless-plated microelectrodes successfully demonstrated the platform's effectiveness in the direct counting of HeLa cells.

Spatiotemporal behaviors of absolute density of atomic oxygen in a planar type of Ar/O2 non-equilibrium atmospheric-pressure plasma jet

Abstract: A method combining of two-photon absorption laser-induced fluorescence and vacuum ultra-violet absorption spectroscopy is constructed and used to get the fine spatial distribution of O generated by a planar type of Ar/O2 non-equilibrium atmospheric-pressure plasma jet. The O density in the quasi-uniform region, which occupies about 80% of the total plasma width, is as high as 1015 cm−3. The lifetime of O is estimated to be about 360 ± 60 µs. The loss of O atoms is due to the three-body reaction of O + O2 + Ar → O3 + Ar confirmed by a simple calculation with a few rate equations. The results are very useful for the simulation of Ar/O2 plasmas, the design of large-scale planar plasma jets and the development of their potential applications.

Effects of nitrogen plasma post-treatment on electrical conduction of carbon nanowalls

Abstract: For utilization in future electronic application of graphene materials, nitrogen (N) atom doping into graphene sheets is an important technology. We investigated the electrical conduction of carbon nanowalls (CNWs), consisting of stacks of graphene sheets standing vertically on substrates. By post-treatment for 30 s, the electrical conductivity of CNWs increased. On the other hand, as the post-treatment time increased, the electrical conductivity decreased. According to Hall measurement, the carrier density decreased with increasing post-treatment time, while the carrier mobility increased. Consequently, the electrical conduction of the CNWs was successfully controlled by N2 plasma treatment.

Characterization of human influenza viruses in Lebanon during 2010-2011 and 2011-2012 post-pandemic seasons.

Abstract: Objective: To genetically characterize human influenza viruses and their susceptibilities to antivirals during two post-pandemic seasons in Lebanon. Methods: Influenza virus was isolated from nasopharyngeal swabs that were obtained from patients with influenza-like illness during 2010-2012 and further analyzed both phenotypically and genotypically. Results: During the 2010-2011 season, both 2009 pandemic H1N1 (H1N1p) and B viruses co-circulated with equal prevalence, while the H3N2 virus predominated during the 2011-2012 season. All H3N2 and H1N1 viruses were resistant to amantadine. Importantly, all viruses of the influenza A and B types were susceptible to the neuraminidase (NA) inhibitors oseltamivir, zanamivir, peramivir, and laninamivir. Nonetheless, all 2011-2012 H1N1p isolates had three mutations (V241I, N369K, and N386S) in the NA gene that were suggested to be permissive of the H275Y mutation, which confers resistance to oseltamivir. We also detected one H1N1p virus during the 2010-2011 season with a 4-fold decrease in susceptibility to oseltamivir due to an NA-S247N mutation. This isolate was phylogenetically distinct from other H1N1p viruses that were isolated in other regions. Conclusions: Influenza A viruses with reduced susceptibility to oseltamivir and mutations permissive for acquiring NA resistance-conferring mutation with minimal burden on their fitness were isolated in Lebanon.

Effectiveness of trivalent influenza vaccine among children in two consecutive seasons in a community in Japan

Abstract: Influenza vaccination is considered the single most important medical intervention for the prevention of influenza. The dose of trivalent influenza vaccine in children was increased almost double since 2011/12 season in Japan. We estimated the influenza vaccine effectiveness for children 1-11 years of age using rapid test kits in Isahaya City, involving 28,884 children-years, over two consecutive influenza seasons (2011/12 and 2012/13). Children were divided into two groups, vaccinated and unvaccinated, according to their vaccination record, which was obtained from an influenza registration program organized by the Isahaya Medical Association for all pediatric facilities in the city. There were 14,562 and 14,282 children aged from 1-11 years in the city in 2011 and 2012 respectively. In the 2011/12 season, the overall vaccine effectiveness in children from 1-11 years of age, against influenza A and B were 23% [95% confidence interval (CI): 14%-31%] and 20% [95% CI: 8%-31%], respectively. In the 2012/13 season, vaccine effectiveness against influenza A and B was 13% (95% CI: 4%-20%) and 9% (95% CI: -4%-21%), respectively. The vaccine effectiveness was estimated using the rapid diagnosis test kits. Age-stratified estimation showed that vaccine effectiveness was superior in younger children over both seasons and for both virus types. In conclusion, the trivalent influenza vaccine has a significant protective effect for children 1-11 years of age against influenza A and B infection in the 2011/12 season and against influenza A infection in the 2012/13 season in a community in Japan.

Hierarchical regrowth of flowerlike nanographene sheets on oxygen-plasma-treated carbon nanowalls

Abstract: Cauliflorous nanographene sheets were hierarchically regrown on the spearlike structures of carbon nanowalls (CNWs) produced by O2-plasma etching. The spears on the CNWs acted as a stem for the growth of flowerlike flaky nanographene sheets, where the root of the nanoflower was located at a defect or disordered site. The defects on the graphitic structures were induced by irradiation with oxygen-related radicals and ions in the O2-based plasmas and acted as sites for the nucleation of flowerlike nanographene. The porous carbon nanostructures regrown after O2-plasma treatment have a relatively higher surface area and are thus promising materials for electrochemical applications.

Recovery of atom density drift caused by change in reactor wall conditions by real-time autonomous control

Abstract: In plasma etching processes, temporal changes in atom densities need to be avoided since the ratio of atom densities is known to directly determine feature profiles. For H2 and N2 mixture plasmas, temporal changes in H and N atom densities are affected by chamber wall conditions, particularly after air exposure. Here we demonstrate that a new feedback control system recently developed by us could autonomously recover atom densities to the intended values in real time, on the basis of vacuum ultraviolet absorption spectroscopy measurements. Real-time process control is thus crucially achieved to suppress fluctuations in feature profiles due to plasma etching.

Temporal changes in absolute atom densities in H2and N2mixture gas plasmas by surface modifications of reactor wall

Abstract: Real time vacuum ultraviolet absorption spectroscopic (VUVAS) measurements revealed that temporal changes in absolute atom densities in H2 and N2 mixture gas (H2/N2) plasmas were affected by the conditions of the reactor inner wall-surface made of anodically-oxidized aluminum. Depending on preceding processes prior to the H2/N2 plasma process, N and H atom densities decreased for a nitrided wall surface, while no change occurred for a hydrogenated surface. Thus, the process history was revealed in the loss-properties of atoms on the reactor wall-surfaces. Suppressing the temporal variations in the gas-phase atom density is crucially important for realizing the precise control of the material processing with a high reproducibility.

A case of pediatric live-donor liver transplantation with a left lateral segment reduction by a linear stapler after reperfusion.

Abstract: In pediatric LDLT, graft reduction is sometimes required because of the graft size mismatch. Dividing the portal triad and hepatic veins with a linear stapler is a rapid and safe method of reduction. We herein present a case with a left lateral segment reduction achieved using a linear stapler after reperfusion in pediatric LDLT. The patient was a male who had previously undergone Kasai procedure for biliary atresia. We performed the LDLT with his father's lateral segment. According to the pre-operative volumetry, the GV/SLV ratio was 102.5%. As the patient's PV was narrow, sclerotic and thick, we decided to put an interposition with the IMV graft of the donor between the confluence and the graft PV. The graft PV was anastomosed to the IMV graft. The warm ischemic time was 34 min, and the cold ischemic time was 82 min. The ratio of the graft size to the recipient weight (G/R ratio) was 4.2%. After reperfusion, we found that the graft had poor perfusion and decided to reduce the graft size. We noted good perfusion in the residual area after the lateral edge was clamped with an intestinal clamp. The liver tissue was sufficiently fractured with an intestinal clamp and then was divided with a linear stapler. The final G/R ratio was 3.6%. The total length of the operation was 12 h and 20 min. The amount of blood lost was 430 mL. No surgical complications, including post-operative hemorrhage and bile leakage, were encountered. We believe that using the linear stapler decreased the duration of the operation and was an acceptable technique for reducing the graft after reperfusion.

Vehicle driving system, control apparatus for vehicle driving system and control method for vehicle driving system

Abstract: A clutch mechanism is configured to selectively change between a first power transmission path and a second power transmission path. The first power transmission path Is configured to transmit torque to an output shaft via a transmission mechanism. The second power transmission path is configured to transmit the torque to the output shaft via a continuously variable transmission mechanism. An electronic control unit is configured to: (a) selectively change a power transmission path during traveling to one of the first power transmission path and the second power transmission path by controlling the clutch mechanism; and (b) in changing the power transmission path by controlling the clutch mechanism, control an operating point of the internal combustion engine during a change of the power transmission path so that the operating point crosses over an optimum fuel, consumption line of the internal combustion engine.

Nanostructure modification to carbon nanowall surface employing hydrogen peroxide solution

Abstract: Carbon nanowalls (CNWs), which are three-dimensional carbon nanomaterials consisting of stacks of graphene sheets vertically standing on substrates, possess a mazelike architecture containing high-density graphene edges and large-area plane surfaces. A selective morphological modification technique for the surfaces of CNWs after their growth has been developed employing hydrogen peroxide (H2O2) solution. It was found that oxidative radicals in H2O2 solution formed characteristic nanometer-scale asperities on the CNW surface without etching from the top edges. Photoelectron spectra indicate that hydroxyl adsorption and subsequent reactions at the edge and plane of graphene contribute to the selective morphological change on the CNW surface.

A construction of diffusion processes associated with sub-Laplacian on CR manifolds and its applications

Abstract: A diffusion process associated with the real sub-Laplacian $\Delta_b$, the real part of the complex Kohn-Spencer laplacian $\square_b$, on a strictly pseudoconvex CR manifold is constructed via the Eells-Elworthy-Malliavin method by taking advantage of the metric connection due to Tanaka-Webster. Using the diffusion process and the Malliavin calculus, the heat kernel and the Dirichlet problem for $\Delta_b$ are studied in a probabilistic manner. Moreover, distributions of stochastic line integrals along the diffusion process will be investigated.

Nonaqueous electrolyte secondary cell and method for producing same

Abstract: The present invention provides a nonaqueous electrolyte secondary cell (10) that comprises the following: an electrode unit (50) comprising a positive electrode (64) and a negative electrode (84); and a nonaqueous electrolyte. The negative electrode (84) comprises a negative electrode current collector (82) and a negative electrode mix layer (86) that contains at least a negative electrode active substance and is formed on the surface of the negative electrode current collector (82). A coating film containing at least boron (B) and sodium (Na) is formed on the surface of the negative electrode active substance in the negative electrode mix layer (86), and assuming that A is the amount [µg/cm 2 ] of sodium (Na) and B is the amount [µg/cm 2 ] of boron (B) contained in the coating film per unit surface area of the negative electrode mix layer (86), the ratio A/B is less than 0.1.

Live demonstration: A CMOS sensor platform with 1.2 µm × 2.05 µm electroless-plated 1024 × 1024 microelectrode array for high-sensitivity rapid direct bacteria counting

Abstract: High-sensitivity rapid direct bacteria counting is an essential key method for point-of-care testing. Counting pathogens (cells, viruses, and bacteria) directly in real time with high sensitivity is useful in maintaining human health and preventing pandemics or bioterrorism. However, conventional counting methods with high sensitivity such as the polymerase chain reaction and cultivation-based biochemical testing are time consuming and require controlled places and well-trained staff. On the other hand, conventional rapid approaches such as immuno-chromatography and ATP bioluminescence schemes are insufficient with respect to sensitivity. As an alternative, electro-chemical sensing approaches using a microelectrode have been intensely investigated because of its high-sensitivity, simplicity, and high-throughput. In this work, a CMOS sensor platform with a bacteria-sized (1.2 µm × 2.05 µm) Au electroless-plated 1024 × 1024 microelectrode array for high-sensitivity rapid direct bacteria counting is demonstrated. For high-sensitivity direct pathogen counting, Au microelectrodes are required to be as small as the target cell. By improving a self-aligned electroless plating technique, the size of microelectrodes on a CMOS sensor chip was successfully reduced to 1.2 µm × 2.05 µm, corresponding to 1/20th of the smallest size reported in literature. Two test chips with 1024 × 1024 and 32 × 32 sensor arrays were fabricated in a 0.6-µm CMOS process and microelectrodes were formed on them using electroless plating. In this demonstration, 2D counting used 32 × 32 sensor arrays with silicone (fig. 1) by CV is introduced.

Single-Walled Carbon Nanotube Growth with Narrow Diameter Distribution from Pt Catalysts by Alcohol Gas Source Method

Abstract: Single-walled carbon nanotube (SWCNT) growth were carried out on SiO2/Si substrates using Pt catalysts at different temperatures, from 400°C to 700°C, under various ethanol pressures by an alcohol gas source method, a type of cold-wall chemical vapor deposition (CVD). Raman measurements showed that the optimal ethanol pressure decreased as the growth temperature was reduced, and that SWCNTs grew even at 400°C by optimizing the ethanol pressure to 1× 10-5 Pa in a high vacuum system. Compared to the SWCNTs grown from Co catalysts, the diameters of SWCNTs grown from Pt were smaller, irrespective of the growth temperature. In addition, both the SWCNT diameter and the distribution became narrower by reducing the growth temperature and we obtained small-diameter SWCNTs of which the diameters were less than 1 nm using Pt catalysts.

Apparatus and method for producing group III nitride semiconductor device and method for producing semiconductor wafer

Abstract: The production apparatus includes a shower head electrode, a susceptor for supporting a growth substrate, a first gas supply pipe, and a second gas supply pipe. The first gas supply pipe has at least one first gas exhaust outlet and supplies an organometallic gas containing Group III metal as a first gas, and the second gas supply pipe supplies a gas containing nitrogen gas as the second gas. The distance between the shower head electrode and the susceptor is greater than the distance between the first gas exhaust outlet of the first gas supply pipe and the susceptor.

Applicability of Bayesian Methods for Loss Ratio Estimation

Abstract: In an earlier paper, we proposed a Bayesian approach towards estimating the Value-at-Risk of an insurance loss ratio, taking into account both the parameter risk and the model risk. In this paper, we apply the approach to real data and evaluate the plausibility of the estimators.

Aromatic C—H Coupling with Hindered Arylboronic Acids by Pd/Fe Dual Catalysts.

Abstract: The dual catalytic system enables the synthesis of sterically hindered heteroaryls and styrene derivatives under aerobic conditions without any stoichiometric co-oxidants.