Concentration of docosahexaenoic acid in glyceride by hydrolysis of fish oil withcandida cylindracea lipase

In an attempt to concentrate the content of DHA (docosahexaenoic acid) in a glyceride mixture containing triglyceride, diglyceride and monoglyceride, fish oil was hydrolyzed with six kinds of microbial lipase. After the hydrolysis, free fatty acid was removed and fatty acid components of the glyceride mixtures were analyzed. When the hydrolysis withCandida cylindracea lipase was 70% complete, the DHA content in the glyceride mixture was three times more than that in the original fish oil. The EPA (eicosapentaenoic acid) content became almost 70% of the original fish oil. Hydrolysis with other lipases did not result in an increase in the DHA content in the glyceride mixtures. Hydrolysis of DHA-rich tuna oil (DHA content is about 25%) withCandida cylindracea lipase resulted in 53% DHA in the glyceride mixture. The EPA content, however, remained close to that of the original tuna oil. In this report, the acyl chain specificity of lipases is evaluated in terms of hydrolysis resistant value (HRV). HRV is the ratio between the DHA contents in the glyceride mixture of hydrolyzed oil and original oil. HRV clearly indicates differences in hydrolysis between DHA and other fatty acids (e.g., saturated and monoenoic acids).     

Preparation and photoconduction of rapidly quenched films in the Bi2O31bM2O5 system (M=V,Nb and Ta)

The Bi₂O₃1bM₂O₅ films (M=V, Nb and Ta) were prepared by a rapid quenching technique using a twin-roller type equipment. Quenched film of pure Bi₂O₃ partially precipitated a tetragonal phase which differs from well-known β-Bi₂O₃ in structure. In every (Bi₂O₃)_0.975 (M₂O₅)_0.025 composition (2.5% M₂O₅), the tetragonal phase was obtained as single phase, and the tetragonality became greater than that of the pure Bi₂O₃. Beyond this composition, the tetragonality decreased to form δ-phase with a fcc structure with increasing the M₂O₅ content. The lowest V₂O₅ content forming a δ-phase was 5%, while a slight tetragonality still remained in the samples containing 10% Nb₂O₅ and 10% Ta₂O₅, respectively. From the measurement of the photoconductivities of the quenched films, it was proved that a photoconduction appeared in the tetragonal phase while no photoconductivity was observed in the cubic phase. The characteristic of the photoconduction was that a remarkable decrease in the resistivity was observed when a light of ca. 500 nm in wave length was irradiated on the films.     

Performance of compression/absorption hybrid refrigeration cycle with propane/mineral oil combination

This paper discusses the feasibility of a vapor compression/absorption hybrid refrigeration cycle for energy saving and utilization of waste heat. The cycle employs propane as a natural refrigerant and a refrigeration oil as an absorbent. A prototype of the cycle is constructed, in which a compressor and an absorption unit are combined in series. The performance of the cycle is examined both theoretically and experimentally. Although the solubility of the propane with the oil is not enough as a working pair in the absorption unit, the theoretical calculation shows that the hybrid cycle has a potential to achieve a higher performance in comparison with a simple vapor compression cycle by using the waste heat. In the experiment, the prototype cycle is operated successfully and it is found that an improvement of an absorber is necessary to achieve the good performance close to the theoretical one. The application of an AHE (absorber heat exchanger) can reduce the heat input to a generator. Further examinations on some other combinations of refrigerant/refrigeration oil and additives are desirable.     

Design of wavelength-flattened coupler using a novel diagram

A novel diagram which describes the condition of 3 dB coupler is proposed. Using the proposed diagram, the design of a wavelength-flattened 3 dB directional coupler composed of a uniform coupled waveguide is investigated. Normalized waveguide parameters are introduced to characterize a five-layer planar waveguide. This enables us to generalize the discussion and to reduce the number of parameters required for characterizing a coupled waveguide. A broadband 3 dB coupler having 50±5% coupling ratio over a wavelength range of 1.1-1.7 μm is designed     

Permeation and separation of organic liquid mixtures through liquid-crystalline polymer networks

A side-chain liquid-crystalline polymer (LCP) was synthesized by the addition of the mesogenic monomer to poly(methyl siloxane) in presence of a Pt-catalyst. When an aqueous solution of 10wt% ethanol was permeated through a LCP membrane by pervaporation at various temperatures, the permeation rate increased with increasing temperature and drastically changed at glass-nematic (Tg) and nematic-isotropic (TNI) transition temperatures of the LCP membrane. The LCP membrane exhibited the waterpermselectivity in the glassy and liquid-crystalline states. The ethanol concentration in the permeate increased with increasing permeation temperature and the LCP membrane changed from the waterpermselectivity to the ethanol-permselectivity around TNI. These results suggested that the permselectivity was influenced by the change of the LCP membrane structure, that is, its state transformation. It was found that a balance of the orientation of mesogenic groups and flexibility of siloxane chains is very important for the permeability and selectivity.     

Left ventricular regional systolic motion in patients with right ventricular pressure overload

The highly reactive and cytotoxic hydroxyl radical (OH) was found by electrochemical detection to be produced in reactions involving hydrogen peroxide (H2O2) and the nitric oxide (NO) donor diethylamine- NO complex. Using aromatic hydroxylation of salicylate as a specific indicator of OH, three salicylate hydroxylation products were identified; catechol, 2,3- and 2,5-dihydroxybenzoic acid. Four additional compounds were detected but not identified. The interactions of H2O2 and NO represent a biologically feasible reaction mechanism that can account for OH-induced damage in cellular environments where transition metal ions are unavailable for participation in the superoxide-mediated Fenton reaction. The ability of the NO/H2O2 complex to generate OH independently of iron or other transition metals provides a new focus for studies concerned with the origin of tissue-specific damage caused by oxygen-derived species.     

Two-dimensional electrophoretic analysis of humoral responses to culture filtrate of Mycobacterium bovis BCG in patients with leprosy and tuberculosis

Various aspects of our communication are well known to have changed over time (1-3). This article describes a cross-sectional study that examined the acoustic characteristics of two groups of Australian women aged 18-25 years from recordings made in 1945 and 1993 and investigated the possible changes in the voice across generations. Archival recordings from 1945 which had been used in a longitudinal study (4) were compared to recordings made in 1993. The results of this study show that women in 1993 have significantly deeper voices than women of the same age recorded in 1945. The possible factors influencing this change are discussed.     

Modification of mesophase pitch by blending Part 2 Modification of mesophase pitch fibre precursor with thermoresisting polyphenyleneoxide (PPO)

Polyphenyleneoxide was blended in amounts of 5 or 10 wt% into petroleum-derived mesophase pitch to reinforce the pitch fibre before the oxidative stabilization to achieve better handling properties. Although polyphenyleneoxide was fusible but hardly soluble in the mesophase pitch even at a spinning temperature of 350° C, blended pitch could be smoothly spun into pitch fibre 10m diameter, as could the parent pitch. Fibrous polyphenyleneoxide of less than 1m diameter was homogeneously dispersed in the pitch fibre, being arranged along the fibre axis. Such fibrous polyp henyleneoxide reinforced the pitch fibre considerably. The fibrous substances at the centre of the fibre disappeared in the carbonized fibre at 1300° C after oxidation at 250° C, although some short ones were observed in the skin region of the fibre, suggesting that polyphenyleneoxide was co-carbonized to be assimilated with mesophase pitch at the centre of the fibre, where the effects of oxidation may be rather limited. The oxidation reactivity and its mechanical strength after carbonization were slightly lower in comparison with those of the parent mesophase pitch.     

Crystallization of potassium titanate from the amorphous phase

By using amorphous potassium titanates as the starting materials, a sintered body of K₂Ti₄O₉ or K₂Ti₆O₁₃ with porous and fibrous textures was prepared. K₂Ti₂O₅ and a new phase, K₆Ti₄O₁₁ were synthesized by the thermal reaction of KNO₃ with TiO₂ at 1000° C for 10 to 20 h. On leaching in water to expel excess of potassium ions, both phases became amorphous. After mixing and moulding these amorphous materials in the desired proportion, a sintered body containing fibrous crystals of K₂Ti₄O₉ was readily fabricated by heating at 1000° C for 12 h. When 5 wt % B₂O₃ was added to the amorphous phases, single phase K₂Ti₆O₁₃, with a fibrous texture grew well on heating at 1000° C for 12 h. Addition of PVA polymer to the amorphous phases was responsible for controlling the porosity of the sintered body, e.g. about 52% theoretical density at 20 wt% PVA polymer. The optimum conditions for preparing the amorphous phases were systematically examined and the effect of the chemical reaction environments, such as different crucible materials on the calcination of KNO₃ and TiO₂ were also discussed.     

Formation of monodispersed Ta2O5 powders

The Ta₂O₅ powders synthesized by the hydrolysis of tantalum pentaethoxide, Ta(OC₂H₅)₅ in alcoholic solution were monodispersed fine oxide particles, which were a uniform, spherical shape, non-agglomerate, and had a narrow size distribution. They grew to 1.2m after ageing for 1 h after hydrolysis. Powder X-ray diffraction and differential thermal analysisthermogravimetric analysis showed the particles were amorphous and hydrated. These particles lost the water at 290° C and gave well-crystalline Ta₂O at 740° C. Throughout these thermal processes, the particle morphology was kept almost the same.