Enantioselective addition Of diketene to aldehydes promoted by chiral schiff base—titanium alkoxide complex. Application to asymmetric synthesis of potential inhibitors of HMG coenzyme reductase

Highly enantioselective addition of diketene to aldehydes was achieved by using novel Schiff base—titanium alkoxide complexes. Up to 92% ee of 5-hydroxy-3-oxoesters was obtained. This procedure provides an efficient method for the asymmetric synthesis of potential inhibitors of HMG coenzyme reductase.     

Mumefural and related HMF derivatives from Japanese apricot fruit juice concentrate show multiple inhibitory effects on pandemic influenza A (H1N1) virus

Fruit-juice concentrate of Japanese apricot (Prunus mume Sieb. et Zucc.) has been shown to be effective against influenza A infection in MDCK cells. In this study, we isolated five components from the fruit-juice concentrate of Japanese apricot, 5-(hydroxymethyl)-2-formylfuran (HMF), 1-[5-(2-formylfuryl)methyl]dihydrogen 2-hydroxypropane-1,2,3-tricarboxylate (mumefural, MF), 2-[5-(2-formylfuryl)methyl]dihydrogen 2-hydroxypropane-1,2,3-tricarboxylate (MF‘), 1-[5-(2-formylfuryl)methyl]hydrogen 1-hydroxyethane-1,2-dicarboxylate (MA1) and 2-[5-(2-formylfuryl)methyl]hydrogen 1-hydroxyethane-1,2-dicarboxylate (MA2), and investigated their inhibitory activities against the novel influenza A/Narita/1/2009 (H1N1) pandemic virus hemagglutinin and neuraminidase functions, which are essential for viral attachment and budding, respectively. An hemagglutination inhibition assay indicated that MF and MF‘ were effective at minimum hemagglutination concentrations of 3.1 and 6.3 mM, respectively. An inhibition study for sialidase activity of the neuraminidase spike showed that MF was the most active anti-sialidase compound with an IC₅₀ value of 0.21 ± 0.01 mM, followed by MA2 (IC₅₀, 0.71 ± 0.09 mM), MA1 (IC₅₀, 1.64 ± 0.31 mM) and MF‘(IC₅₀, 1.62 ± 0.22 mM). Furthermore, MF was shown to inhibit the growth of the pandemic virus in a dose-dependent manner (62 ± 3% inhibition at 5 mM). The results suggest that MF, a citric acid ester linked to HMF at the 1-position of the propane backbone, might be a lead compound for the development of anti-influenza A inhibitors.     

A quantitative analysis of a trace amount of hydrogen in high temperature heat-treated carbons

A technique to determine a trace amount of hydrogen in carbon materials heat-treated above 1000 °C was developed. Three types of carbons prepared from poly(furfulyl alcohol), poly(vinyl chloride) and mesophase carbon microbeads were heat-treated at various temperatures ranging from 1000 to 1800 °C. Then they were gasified by O₂ in a fixed bed flow reactor, and the H₂O gases formed during the gasification processes were carefully monitored with a Karl Fischer moisture analyzer. As a result, this method makes it possible to determine the hydrogen contents in the carbons down to three places of decimals as a weight percent and can detect even a trace amount of hydrogen as low as 0.002 wt.%. A possible chemical structure of carbon edge sites was also discussed based on the experimentally determined hydrogen contents.     

Quantitative evaluation of display characteristics of AMOLED displays

Abstract— Understanding the display characteristics of OLEDs is not only of general interest but also of technological importance for expanding the application of OLEDs. The display characteristics of AMOLEDs were quantitatively evaluated and compared with LCD or CRT performance. The fast response time and high contrast ratio, which are attractive characteristics of OLEDs, were also retained under low temperature and bright ambient, respectively. Moreover the luminance and color barely changed with viewing angle at any gray‐scale level. The optical design of OLED diodes is important for the emission characteristics, luminance, and color reproducibility.     

Service-oriented mobility management architecture for seamless handover in ubiquitous networks

In ubiquitous wireless LANs, a mobile node is likely to move between many access points while using certain applications. However, in the conventional Internet architecture, an MN can never inherently avoid the degradation in communication quality during handover. To achieve seamless handover, we propose a service-oriented mobility management scheme to address application quality. In this article, we first clarify three requirements for achieving seamless handover. We then describe our concept of the service-oriented mobility management scheme, which satisfies all three requirements. Our main contribution is the proposal of a scheme of how to properly use the number of frame retransmissions as a new handover-decision criterion to accomplish seamless handover. Performance evaluations show that our proposed scheme can maintain application quality during handover     

Incorporation of Dust Particles into a Growing Film During Silicon Dioxide Deposition from a TEOS/O2 Plasma

The effects of gas flow rate on particle formation and film deposition during the preparation of silica thin film using a TEOS/O₂ plasma were investigated. Particle formation and growth are suppressed with increasing gas flow rates. The film deposition rate increases with increasing gas flow rate, reaches a maximum value, and eventually decreases again. However, the uniformity of the film tends to degrade at high gas flow rates. At a high gas flow rate, some particles trapped in the sheath near the grounded electrode pass through the sheath to reach the substrate and are then embedded in the growing film. A self-consistent sheath model combined with particle force balance based on charge fluctuation was developed to explain these experimental findings qualitatively. The model reveals that charge fluctuation is a key factor for the particle to overcome the potential barrier of the negatively charged particles to pass through the sheath, eventually reaching the substrate. The model further shows that the probability of a particle being deposited on the substrate is higher for increased gas flow rates, which correctly predicts the experimentally observed trend.     

Research on some basic deformations in free forging with robot and servo-press

Due to the disadvantages in casting or hot forging of Ti alloy artificial bones, such as low strength and high energy cost, this paper prompted an alternative method to manufacture individuated artificial bones. Free forging with a 6-axis freedom robot and servo-press could be very economical in the forming of complex shape parts because of its high flexibility and simple die-setting. Based on this system, the authors studied deformations of some basic elements, which could be assembled to artificial bones with complex shape. Firstly, the compression limit and effect of compression parameters on the roundness during reducing diameter process were declared for Al alloy and pure Ti. Secondly, an approximate theoretical equation of bending angle or curvature radius was proposed, and it matches experimental results well. Finally, a dimension prediction equation was presented by considering effect of material anisotropy, and then the ladder part without width spread was manufactured accordingly.     

Structurally Diverse Polyamines: Solid‐Phase Synthesis and Interaction with DNA

A versatile solid‐phase approach based on peptide chemistry was used to construct four classes of structurally diverse polyamines with modified backbones: linear, partially constrained, branched, and cyclic. Their effects on DNA duplex stability and structure were examined. The polyamines showed distinct activities, thus highlighting the importance of polyamine backbone structure. Interestingly, the rank order of polyamine ability for DNA compaction was different to that for their effects on circular dichroism and melting temperature, thus indicating that these polyamines have distinct effects on secondary and higher‐order structures of DNA.     

Isolation and characterization of poly(butylene succinate-co-butylene adipate)-degrading microorganism

Poly(butylene succinate-co-butylene adipate) (PBSA)-degrading bacterium, strain 1-A, was isolated from soil. Strain 1-A was identified as Bacillus pumilus on the basis of its physiological properties and partial 16S rRNA gene sequence. Strain 1-A also degraded poly(butylene succinate) (PBS) and poly(epsilon-caprolactone). On the other hand, poly(butylene adipate terephthalate) and poly(lactic acid) were minimally degraded by strain 1-A. The NMR spectra of degradation products from PBSA indicated that the adipate units were more rapidly degraded than 1,4-butanediol and succinate units. This seems to be one of the reasons why strain 1-A degraded PBSA faster than PBS.     

High-rate deposition of hydrogenated amorphous silicon films using inductively coupled silane plasma

Inductively coupled plasma (ICP) generated at 13.56 MHz has been employed for high-rate deposition of device-quality hydrogenated amorphous silicon (a-Si:H). It has been shown that an increase in the flow rate of a monosilane gas enhances the generation rate of deposition precursors, while the ion flux decreases and becomes saturated. The defect density reaches the minimum at a deposition rate of 2.3 nm/s. It has also been demonstrated that even at deposition rates around 4 nm/s, a-Si:H deposited at 150°C exhibits a subgap defect density lower than 6×10¹⁶ cm⁻³ after 12 h AM1 (100 mW/cm²) light soaking.