New amphoteric surfactants derived from lysine. I. Preparation and properties of Nε-acyllysine derivatives-acyllysine derivatives

New amphoteric surfactants were prepared from N^ε-acyllysine which was obtained by the thermal dehydration of a higher fatty acid salt of lysine and was not soluble in water. N^α,N^α-dimethyl-N^ε-acyllysine was prepared by the catalytic reductive condensation of N^ε-acyllysine ester with formaldehyde in good yield. N^α,N^α,N^α-trimethyl-N^ε-acyllysine was obtained from the reaction of N^α,N^α-dimethyl-N^ε-acyllysine ester with methyl iodide. Confirmation of the structure of these derivatives was obtained by spectrometric and spectroscopic analyses. The solubility of N^ε-acyllysine was improved significantly by the introduction of N^α-methyl groups. Physicochemical and surface active properties of the derivatives were investigated in terms of isoelectric points, dissolution temperatures, surface tensions, critical micelle concentrations (cmc), foaming properties and wetting powers. N^α,N^α,N^α-trimethyl-N^ε-acyllysine had lower dissolution temperatures than N^α,N^α-dimethyl-N^ε-acyllysine. The latter showed lower surface tensions than the former at cmc. N^α,N^α-dimethyl-N^ε-lauroyllysine was best in wetting power and foaming property.     

Intelligent decision support systems for nuclear power plants in Japan

This paper describes the MITI (Ministry of International Trade and Industry) projects for decision support systems for NPPs in Japan. Main attention is paid to the new project of an advanced man-machine system for nuclear power plants, of which a conceptual design was initiated in 1984. Some of the aspects of the design and the outline of the prototype system are discussed.     

Effects of the additions of B,P, dSn,and Sb on oxygen assisted hydrogen embrittlement of nickel

Effects of additions of B, P, Sn, and Sb on hydrogen embrittlement of nickel were examined on specimens cathodically charged with hydrogen. Tensile specimens were annealed either in vacuum or in a dry hydrogen gas. Undoped, Sn-doped, and Sb-doped materials annealed in vacuum revealed high susceptibility to intergranular hydrogen embrittlement, while the susceptibility was greatly reduced when the materials were annealed in hydrogen. The deleterious effect of vacuum annealing was proposed to result from grain boundary penetration of oxygen from the annealing environment. Additions of a small amount of B and P almost completely suppressed the IGHE of specimens annealed in vacuum. It is suggested that the effect of these elements on grain boundary penetration of oxygen is an important factor for their beneficial effects on IGHE. Addition of Sn somewhat increased the ductility of hydrogen charged specimens annealed both in vacuum and in hydrogen, indicating that this element is not deleterious. Addition of Sb increased the embrittlement susceptibility of specimens annealed in hydrogen. However, the deleterious effect of Sb was not serious in spite of the high concentration of Sb that was examined.     

Mitral valve repair in a patient with severe porcelain aorta

We repaired the mitral valve in a patient with severe porcelain aorta. Significant mitral regurgitation developed in a 66-year-old woman with heavy calcification throughout the whole aorta. At operation, cardiopulmonary bypass was properly established by combined axillary and femoral arterial cannulations for sufficient systemic flow. Likewise, the combination of a superior mitral approach and profound hypothermic fibrillatory arrest in conjunction with low-flow cardiopulmonary bypass allowed us to repair the mitral valve successfully.     

Thin hydroxyapatite layers formed on porous titanium using electrochemical and hydrothermal reaction

In our previous study, it was found that hydroxyapatite (HA) microcrystals were precipitated by hydrothermal treatment on an anodic titanium oxide film containing calcium and phosphorus (AOFCP) with an equivalent Ca/P ratio to HA, which was formed on a titanium metal anode in an aqueous electrolytic solution of dissolved calcium acetate and -glycerophosphate. In this study, the formation mechanism of the AOFCP has been clarified. Spark discharges, which occur on titanium surface with a large amount of heat generation, cause crystallization of the TiO₂ matrix of the AOFCP and incorporation of calcium and phosphorus into the matrix from these electrolytes simultaneously. The calcium and phosphorus in the matrix seem to exist as ions rather than as calcium phosphate. Also, thin HA layers consisting of the many precipitated microcrystals can be uniformly formed even on titanium with complex shapes or surface geometries such as the mesh, roughened surfaces and bead-coated porous coating by the present method.     

Spectral Narrowing of a Varactor-Integrated Resonant-Tunneling-Diode Terahertz Oscillator by Phase-Locked Loop

Spectral narrowing of a resonant-tunneling-diode (RTD) terahertz oscillator, which is useful for various applications of terahertz frequency range, such as an accurate gas spectroscopy, a frequency reference in various communication systems, etc., was achieved with a phase-locked loop system. The oscillator is composed of an RTD, a slot antenna, and a varactor diode for electrical frequency tuning. The output of the RTD oscillating at 610 GHz was down-converted to 400 MHz by a heterodyne detection. The phase noise was transformed to amplitude noise by a balanced mixer and fed back into the varactor diode. The loop filter for a stable operation is discussed. The spectral linewidth of 18.6 MHz in free-running operation was reduced to less than 1 Hz by the feedback.     

Towards Tuneable Retaining Glycosidase‐Inhibiting Peptides by Mimicry of a Plant Flavonol Warhead

Retaining glycosidases are an important class of enzymes involved in glycan degradation. To study better the role of specific enzymes in deglycosylation processes, and thereby the importance of particular glycosylation patterns, a set of potent inhibitors, each specific to a particular glycosidase, would be an invaluable toolkit. Towards this goal, we detail here a more in‐depth study of a prototypical macrocyclic peptide inhibitor of the model retaining glycosidase human pancreatic α‐amylase (HPA). Notably, incorporation of l ‐DOPA into this peptide affords an inhibitor of HPA with potency that is tenfold higher (K_i=480 pm ) than that of the previously found consensus sequence. This represents a first successful step in converting a recently discovered natural‐product‐derived motif, already specific for the catalytic side‐chain arrangement conserved in the active sites of retaining glycosidases, into a tuneable retaining glycosidase inhibition warhead.     

Influence of Oxygen Ion Conduction on Nitric Oxide Decomposition

Ba₂In₂O₅, Ba₂Y₄O₉, and BaLa₂O₄ having brownmillerite-related structures were synthesized. Ionic conductivity and catalytic activity following the reduction of NO to N₂ were also investigated, both of which increased at the order-disorder transition temperature for oxygen vacancies of these compounds. It was made clear that the catalytic activity of NO decomposition reaction increased with a decrease in the order–disorder transition temperature. Moreover, it was found that ionic conductivity contributed to the catalytic activity of NO reduction to N₂.     

Fiber Formation in Medium and Ultra‐High‐Molecular‐Weight Polyhydroxybutyrate Blends under Shear Flow

Summary: Polyhydroxybutyrate (PHB) is an ideal bioplastic, however, this polymer undergoes a severe embrittlement process because of its spherulitic structure, rendering the material brittle. Using a series of in‐situ rheo techniques, we have previously observed only the rapid initial stage of shish formation, we term a partial shish, which existed at high shears in medium‐molecular‐weight PHB, = 360 000. The shish kebab morphology is anticipated to remove or severely lessen this embrittlement process whilst providing new properties and applications. For medium and ultra high‐molecular‐weight (MMWT, = 360 000/UHMWT, = 5 × 10⁶) PHB 99/1 and 99.5/0.5 blends only a partial shish is identified. However, the initial shish formation stage and subsequent stages were observed at 98/2 and 97/3 blend ratios resulting in a complete shish, we term the full shish, and fiber formation was evident. We believe this fiber morphology achieved by high molecular weights is crucial to sustaining the shish kebab structure for an excessive period.

Left: In‐situ rheo‐light scattering micrograph; 97/3 MMWT/UHMWT PHB at 100 s^?1 for 1 s shear shish held at 75 s. Right: In situ rheo‐optical micrograph; PHB fiber morphology observed at 50 s^?1 for 2 s shear 98/2 MMWT/UHMWT PHB after 1 min.