Soft Nanotubes with a Hydrophobic Channel Hybridized with Au Nanoparticles: Photothermal Dispersion/Aggregation Control of C60 in Water

Simple glycolipid N‐alkaroyl‐β‐D‐glucopyranosylamine 1(n) selectively self‐assembles into sheets in water, nanotubes in alcohols, and helical nanocoils in toluene. All self‐assemblies consist of bilayer membranes in which 1(n) packed in an interdigitated fashion. The outer surface of the sheet is covered with the hydrophilic glucose headgroup of 1(n), whereas those of the nanotube and helical nanocoil are covered with the hydrophobic alkyl‐chain tail of 1(n). Heat treatment of the nanotube in the presence of water induces a rearrangement of the molecular packing of the outermost surface that allows the nanotube to become an effective nanocontainer for the dispersion of fullerene (C60) in water, a result of the ability of the hydrophilic outer surface of the nanotube and the hydrophobic nanochannel to encapsulate C60. The nanotube also exhibits photothermal characteristics after being hybridized with Au nanoparticles (AuNPs). The photothermal effect of the AuNPs allows the nanotube to unfold its tubular morphology and leads to compulsive release of the encapsulated C60 to the bulk water. Application of other nanotubes with similar photostimulated transformation ability should facilitate control of the dispersion/aggregation of other carbon nanomaterials, functional aromatic compounds, and drugs with low solubility in water.     

Disparities of indoor temperature in winter: A cross-sectional analysis of the Nationwide Smart Wellness Housing Survey in Japan

The WHO Housing and health guidelines recommend a minimum indoor temperature of 18°C to prevent cold-related diseases. In Japan, indoor temperatures appear lower than in Euro-American countries because of low insulation standards and use of partial intermittent heating. This study investigated the actual status of indoor temperatures in Japan and the common characteristics of residents who live in cold homes. We conducted a nationwide real-world survey on indoor temperature for 2 weeks in winter. Cross-sectional analyses involving 2190 houses showed that average living room, changing room, and bedroom temperatures were 16.8°C, 13.0°C, and 12.8°C, respectively. Comparison of average living room temperature between prefectures revealed a maximum difference of 6.7°C (Hokkaido: 19.8°C, Kagawa: 13.1°C). Compared to the high-income group, the odds ratio for living room temperature falling below 18°C was 1.38 (95% CI: 1.04-1.84) and 2.07 (95% CI: 1.28-3.33) for the middle- and low-income groups. The odds ratio was 1.96 (95% CI: 1.19-3.22) for single-person households, compared to households living with housemates. Furthermore, lower room temperature was correlated with local heating device use and a larger amount of clothes. These results will be useful in the development of prevention strategies for residents who live in cold homes.     

Strain selection and scale-up fermentation for FR901379 acylase production by Streptomyces sp. no. 6907

Micafungin (FK463) is a widely used treatment for life-threatening, deep-seated fungal infections. It is an echinocandin-like lipopeptide derived from the chemical modification of deacylated FR901379, a type of lipopeptide antibiotic produced by Coleophoma empetri F-11899. The palmitoyl moiety of FR901379 is deacylated by FR901379 acylase produced by Streptomyces sp. no. 6907. In this study, our goal was to generate an improved strain of Streptomyces sp. no. 6907 capable of hyperproducing the FR901379-acylase enzyme. To accomplish this goal, modified strains of Streptomyces sp. no. 6907 were generated using UV-irradiation mutagenesis, and strain selection was performed using an agar-plate screening method to efficiently select an acylase-hyperproducing strain. Three marker indices were shown to correlate with elevated acylase production: decreased candidacidal activity of FR901379, decreased proteolytic activity on skim milk, and phenotypic characteristics. Cloning and subsequent sequencing of the acylase gene from the hyperproducing mutant revealed no mutations in either the acylase structural gene or the 5'-flanking region required for gene expression. The growth medium was also modified to maximize acylase production. We successfully increased acylase activity approximately 65-fold, compared with the original growth conditions (wild strain cultured in the original unmodified medium). To minimize formation of excess foam during the fermentation process, we optimized the parameters of agitation speed, as calculated from the discharge flow rate. Using our improved strain and the optimized medium and growth conditions, we have developed an improved and highly reproducible method for stable large-scale production of FR901379-acylase.     

Novel grounded and floating high order immittance simulators using OTAs and OAs

This paper proposes novel grounded and floating high order series and parallel immittance simulators using operational transconductance amplifiers (OTAs) and operational amplifiers (OAs) with a finite gain–bandwidth (GB) product. They are composed of active devices (OTAs and OAs) and resistances, and are suitable for monolithic implementation in either CMOS or bipolar technologies. They also realize both positive and negative high order immittances. The circuit characteristics can be electronically tuned by adjusting the transconductances of OTAs and the GB products of OAs. Any transfer functions are realizable using the proposed simulators. Two examples are shown, together with simulation results.     

Studies on Effective Utilization of SOFC Exhaust Heat Using Thermoelectric Power Generation Technology

Solid oxide fuel cells (SOFCs) are being researched around the world. In Japan, a compact SOFC system with rated alternative current (AC) power of 700 W has become available on the market, since the base load electricity demand for a standard home is said to be less than 700 W AC. To improve the generating efficiency of SOFC systems in the 700-W class, we focused on thermoelectric generation (TEG) technology, since there are a lot of temperature gradients in the system. Analysis based on simulations indicated the possibility of introducing thermoelectric generation at the air preheater, steam generator, and exhaust outlet. Among these options, incorporating a TEG heat exchanger comprising multiple CoSb₃/SiGe-based TEG modules into the air preheater had potential to produce additional output of 37.5 W and an improvement in generating efficiency from 46% to 48.5%. Furthermore, by introducing thermoelectric generation at the other two locations, an increase in maximum output of more than 50 W and generating efficiency of 50% can be anticipated.     

X-Ray photoelectron spectroscopy analysis of plasma-polymer interactions for development of low-damage plasma processing of soft materials

Plasma-polymer interactions have been investigated using atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS) of polyethyleneterephthalate (PET) films, which have been exposed to argon plasmas driven by low-inductance antenna modules as a parameter of ion energy. The AFM images indicated that the argon plasma exposure exhibited a significant change in surface roughness. The XPS analyses suggested that the degradation of chemical bonding structure and/or bond scission of PET could be effectively suppressed in the plasma exposures with ion energies below 6 eV. However, significant degradations of O = C-O bond, C-O bond and phenyl group were observed with increasing ion energy above 6 eV.     

在高纯度理想热耦合精馏塔的双组分控制中考虑过程的非线性

Dual-point composition control for a high-purity ideal heat integrated distillation column (HIDiC) is addressed in this work. Three measures are suggested and combined for overcoming process inherent nonlinearities:(1) variable scaling; (2) multi-model representation of process dynamics and (3) feedforward compensation. Theses trategies can offer the developed control systems with several distinct advantages: (1) capability of dealing with severe disturbances; (2) tight tuning of controller parameters and (3) high robustness with respect to variation of operating conditions. Simulation results demonstrate the effectiveness of the proposed methodology.     

Defect Detection from Visual Abnormalities in Manufacturing Process Using IDDQ

Abnormal I _DDQ (Quiescent V _DD supply current) indicates the existence of physical damage in a circuit. Using this phenomenon, a CAD-based fault diagnosis technology has been developed to enhance the manufacturing yield of logic LSI. This method to detect the fatal defect fragments in several abnormalities identified with wafer inspection apparatus includes a way to separate various leakage faults, and to define the diagnosis area encircling the abnormal portions. The proposed technique progressively narrows the faulty area by using logic simulation to extract the logic states of the diagnosis area, and by locating test vectors related to abnormal I _DDQ. The fundamental diagnosis way employs the comparative operation of each circuit element to determine whether the same logic state with abnormal I _DDQ exists in normal logic state or not.     

Mixing mechanism of three‐tip kneading block in twin screw extruders

In recent years, twin screw extruders have been applied to various kinds of polymer processing. It has been important to find their optimum geometrical configurations and operational processing conditions for the best performance of extrusions and products. Many engineers have been evolving numerical and the experimental methods to characterize the mixing performance for twin screw extruders. We have carried out three‐dimensional flow simulations of kneading blocks in intermeshing co‐rotating twin screw extruders by using the finite element method to quantify their ability in distributive and dispersive mixing. We discuss their performance in distributive mixing for three different type of kneading blocks in terms of the residence time distribution and the nearest distance between markers at various periods of time, by using the marker tracking method. Those numerical techniques and applications of mixing indices have enabled us to quantify and evaluate their abilities in distributive mixing of kneading blocks in twin screw extruders.     

Development on a coaxial heat integrated distillation column (HIDiC)

Various configurations of a column for performing the principle of HIDiC can be proposed, but a coaxial column which is installed a packing in an inside tube and outer side may be one of the simplest columns for HIDiC. In order to examine whether or not the configuration of the packed column mentioned above is appropriate to HIDiC, an experimental apparatus has been set up and heat and mass transfer rates have been measured by using benzene-toluene system. This paper was presented at The 5th International Symposium on Separation Technology-Korea and Japan held at Seoul between August 19 and 21, 1999.