Polymer-coated hollow fiber for CO(2) laser delivery

Hollow fibers for CO(2) laser light have been fabricated with a cyclic olefin polymer as the inner dielectric. A film of cyclic olefin polymer was coated inside the glass capillary tubing by a simple liquid-flowing process. A polymer-coated fiber with a 700-microm bore showed a loss of 0.06 dB/m for CO(2) laser light because cyclic olefin polymer has low absorption at a 10.6-microm wavelength.     

Determining Net Requirements for Material Requirements Planning

This paper presents a design guideline for netting systems that determine net requirements, for push-type production ordering. Two alternative netting systems (full and single) are formulated in an N stage production and inventory system. The performances of the two alternatives are discussed through numerically analysing production ordering variations and inventory level variations at each stage in the processes. The results obtained suggest that: (1) the full netting system is preferable at the production stages, where variance in the accumulated forecast consumption error by the immediately succeeding stage is smaller than the variance in the accumulated forecast market demand error over a production ordering interval and the lead time for the stage. (2) The single netting system may be preferable at the other stages, particularly in regard to production ordering variations.     

An improved apparatus for measuring the inhomogeneity of glasses

An improved apparatus capable of quantatively measuring the inhomogeneity of glasses within several minutes was developed as a prototype for practical use. Inhomogeneities were measured for several kinds of glass articles on the market, such as plate, bottle and optical glasses etc. and a “relative homogeneity” has been proposed for the purpose of deciding a ranking of glasses measured in comparison to the powdered single crystal of CaF₂ as a standard material of uniformity.     

Synthesis of a nitrogen analogue of salacinol and its alpha-glucosidase inhibitory activity.

A nitrogen analogue 4 of the naturally occurring sulfonium ion salacinol (1), a potent alpha-glucosidase inhibitor isolated from the Ayruvedic medicine Salacia reticulata, was synthesized and its inhibitory activity against alpha-glucosidase tested. Substitution of the sulfur atom in 1 with a nitrogen reduced the activity considerably. The solid-state stereostructure of the related compound (5) was determined on the basis of single crystal X-ray measurement.     

High Temperature Thermal Insulation System for Millimeter Wave Sintering of B4C

Boron carbide (B₄C) is one of advanced materials and is being used in a wide rage of applications. The unique feature of this material is its large neutron-absorbing cross-section. Some of its most prominent applications are controlling rods in nuclear reactors and radiation protection. 24 GHz microwave processing for B₄C ceramics were performed under flowing argon gas using the sintering system. Sintering at the high temperature (up to 2200°C) was achieved using thermal insulation system consists of fiber-board, boron nitride powder, and boron nitride case. The sintered samples were achieved 90 % of theoretical.     

Computation of air flows and motion of environmental pollutants over complex geographical topographies

Importance and applicability of numerical flow analysis to environmental science are outlined. Fluid phenomena in the ocean, rivers, atmosphere and the ground are investigated by means of numerical methods and in turn proposals for the control, restoration and counterplans against the so-called environmental disrupters which disorder natural environment as well as ecological systems in nature. All such environmental disrupters diffuse in and are transported by environmental fluids. Those disrupters sometimes react on some other chemicals to generate offensive odor and even more poisonous materials. Environmental fluid dynamics is effective for the evaluation, prediction and restoration of the environmental damage. In this paper we focus our attention on the dynamical analysis of the diffusion and advection processes of environmental disrupters in environmental fluids. The first objective is to make an attempt to formulate a mathematical model for environmental fluids. The second objective is to exhibit some results of numerical simulations of the motion of offensive odor or pollutants in the atmosphere over a complex geographical topography.     

Separation of nucleotides with an aqueous mobile phase using pH- and temperature-responsive polymer modified packing materials.

A new method for the qualitative analysis of adenosine nucleotides (AMP, ADP, and ATP) and synthetic oligonucleotides has been proposed, utilizing a pH- and temperature-responsive polymer of N-isopropylacrylamide (NIPAAm), butyl methacrylate (BMA) and N,N-dimethylaminopropylacrylamide (DMAPAAm) as the stationary phase of HPLC. In the chromatographic system using the copolymer with ionizable groups of modified packing materials, we investigated how to separate adenosine nucleotides and oligonucleotides by temperature. The properties of the surface of the copolymer-grafted stationary phase altered from hydrophilic to hydrophobic and from charged to non-charged due to changes in the temperature and in the pH, respectively. In addition, it is possible to exhibit and hide ion-exchange groups on the polymer chain surface by temperature changes. These phenomena result from changes in the charge and hydrophobicity of the pH- and temperature-responsive polymer on the stationary surface with the controlling temperature. A pH- and temperature-responsive chromatography would be greatly useful for biopolymer and nucleotide separation and purification.     

Progress in 50 years of viroid research—Molecular structure,pathogenicity, and host adaptation

Viroids are non-encapsidated, single-stranded, circular RNAs consisting of 246–434 nucleotides. Despite their non-protein-encoding RNA nature, viroids replicate autonomously in host cells. To date, more than 25 diseases in more than 15 crops, including vegetables, fruit trees, and flowers, have been reported. Some are pathogenic but others replicate without eliciting disease. Viroids were shown to have one of the fundamental attributes of life to adapt to environments according to Darwinian selection, and they are likely to be living fossils that have survived from the pre-cellular RNA world. In 50 years of research since their discovery, it was revealed that viroids invade host cells, replicate in nuclei or chloroplasts, and undergo nucleotide mutation in the process of adapting to new host environments. It was also demonstrated that structural motifs in viroid RNAs exert different levels of pathogenicity by interacting with various host factors. Despite their small size, the molecular mechanism of viroid pathogenicity turned out to be more complex than first thought.