The influence of exogenous cholesterol on the fatty acid composition of liver lipids in the rats given linoleate and γ-linolenate

Three groups of rats were given cholesterol and cholic acid for four weeks, and then fed a diet with 20% lard (group 1), a diet with 4% of the lard substituted by methyl linoleate (group 2), and a diet with 2% substituted by methyl linoleate and another 2% by methyl γ-linolenate (group 3) during the same period. Two control groups (4 and 5) received the same diets as did groups 2 and 3, respectively, but without cholesterol and cholic acid. The hepatic cholesterol accumulation was significantly less in group 3 than in groups 1 and 2, and distinct differences in the degree of plasma cholesterol elevation were found among the cholesterol fed groups (1>2>3). Supplement of γ-linolenate resulted in a reduction of the ratio of arachidonate to homo-γ-linolenate in both the cholesterol-fed group and the control group, but the ratio was much lower in the former. Incorporation of 1-¹⁴C-linoleate and 1-¹⁴C-γ-linolenate into the liver lipids of groups 2 and 4, and groups 3 and 5 was observed respectively at 1 and 3 hr after the intravenous injection. The specific activity of arachidonate from both of the labeled acids in phospholipid and triglyceride was apparently lower in groups 2 and 3 than in groups 4 and 5, respectively. The distribution rate of radioactivities in tetraenoic acids was also low in groups 2 and 3 among the fatty acids of phospholipid and triglyceride. The results indicated impairment of conversion of homo-γ-linolenate into arachidonate in the cholesterol-fed rats.     

Perturbation of Wood Cellulose Synthesis Causes Pleiotropic Effects in Transgenic Aspen

Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility,the overexpression of an aspen secondary wall-associated cellulose syn-thase (PtdCesA8) gene was attempted in transgenic aspen (Populus tremuloides L.) and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing,and weak branches adopted a weeping growth habit. Furthermore,transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem (wood) of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin (35%) and non-cellulosic polysaccharides (55%) compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems produced typical collapsed or 'irregular' xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees.     

Empirical Equation for Calculating the Density of Oxide Glasses

The density of oxide glass including silicate, borate, phosphate, tellurite, and germanate glasses were measured using the Archimedes method. On the assumption that the ionic packing ratio is approximately a constant independent of chemical composition, an empirical equation for estimating the density from chemical composition was proposed. The calculated values are in reasonable agreement with the corresponding measured ones.     

Fabrication of transparent silica glass by powder sintering

Transparent silica glasses were obtained by sintering a green compact (fabricated by slip-casting methods for high-purity silica glass powder) in diverse atmospheres. The relationships between sintering atmosphere and sintering temperature that result in transparent, sintered silica glass were shown. The results indicate that there are four forming phases for each sintering atmosphere and temperature: (1) nontransparent glass resulting from an overabundance of pores (2) crystal, such as cristobalite or β-quartz, (3) moganite, and (4) transparent glass. Optimum sintering temperature for fabricating transparent silica glass was above 1673 K in a high-vacuum (10^–4 Pa: p(O₂) = 10^–14) atmosphere. We investigate the fabrication of transparent and hydroxyl-free silica glass by a powder-sintered method. After studying the effect of sintering schedule on residual [OH^–] concentration for transparent, sintered silica glasses, we sintered a green compact prepared by silica powders with a mean particle size of 1.6 µm, first heating it to 1523 K for dehydration and then to 1873 K for densification. This typical fabricated condition resulted in a transparent, sintered silica glass with <1 ppm [OH^–] concentration.     

A cause of self‐similarity in TCP traffic

We analyse the statistical properties of aggregated traffic flows generated by TCP, in order to clarify a possible cause of self‐similarity in Internet traffic. Using ns‐2 simulation, we first show that aggregated traffic flows by TCP can be characterized by phase transition phenomena between non‐congested and congested phases in statistical physics. Interestingly, although the traffic exhibits self‐similarity with the Hurst parameter H ≈ 1.0 at the critical point between them, it is close to Poissonian away from the critical point. This result is consistent with results from real WAN traffic measurement. The main contribution of our work is to show that TCP itself contains a mechanism for generating self‐similarity, without assuming self‐similarity or long‐range dependency (LRD) in the application layer (e.g. packet inter‐arrival, connection arrival, and file size distribution). Moreover, we find that the value of the Hurst parameter at the critical point is determined by the simple feedback control called stop‐and‐wait flow control. Namely, it appears even without any packet retransmission events and is independent of the explicit rate increment algorithm such as slow‐start and congestion avoidance. Additionally, we demonstrate that the value of the Hurst parameter at the critical point depends on the constant bit rate algorithm and topology of network. Finally, we indicate that the time series of the round trip time follow the same statistics at the critical state. Copyright © 2005 John Wiley & Sons, Ltd.     

Electrolytic aggregation treatment without coagulant dosage for retentate

An electrolytic treatment promoting aggregation compatible with the production of a dense aggregate was developed and studied in a batch test to thicken the retentate without coagulant dosage. A kaolin suspension with turbidity of about 200 NTU with a large fraction of fine particulates was used as the retentate. The aggregation of the electrochemically treated suspension increased with increasing mixing intensity in the range of 40–160 rpm for 5 min. The electrolytic treatment could also decrease the residual turbidity at the retention of about 150 h to one-fourth that of the untreated suspension, and moreover did not significantly change the sludge concentration, in contrast to the decreased sludge concentration of the acidified suspension maintained in the pH range of 4.5–5.0. A positive shift of the surface charge of particulates observed in the treated suspension suggests that the particle destabilization occurred in a pH range of 5.5–7.0, because of the hydrolysis of Al ions released electrochemically from kaolin clay.     

Parametric oscillation of cables and aerodynamic effect

This paper addresses the aerodynamic effect on the nonlinear oscillation, particularly parametric vibration of cables in cable-stayed bridges. A simplified 2-DOF model, including a beam and a stayed cable, is formulated first. Response of the cable under global harmonic excitation which is associated with wind speed is obtained using the multiple scales method. Via numerical analysis, the stability condition of the cable in terms of wind speed is derived. The method is applied to a numerical example and a long-span bridge to analyze its all stay cables. It is demonstrated that very large vibration at one of the longest cables in the middle span of the bridge can be parametrically excited when the wind speed is over around 210 km/h (58.5 m/s).     

Electric characteristics of contact junctions between NbTimultifilamentary wires

Anomalous current-voltage characteristics have been found for a mechanical contact junction between NbTi superconducting multifilamentary wires. The pressure contact junctions between superconductors were created by either parallel-conductor contact or crossed-conductor contact. The junctions are superconductive over a limited current range. The current-voltage characteristics show switching phenomena, that are both large and very fast, at transitions between zero voltage and resistive states. The switching time is about 2 μs. A zero-voltage current of about 60 A was obtained for a 75-mm-long junction at zero applied magnetic field. The current-voltage curve of the junction shows hysteresis that varies with the contact junction's structure. It has been confirmed that mechanical pressure contact junctions can be used as persistent switches without heaters. Additionally, contact junctions may provide uniform current distribution for multistrand cables     

Studies of the effects of the modification conditions on the hydrogenation rate for the enantio-differentiating hydrogenation of methyl acetoacetate over a tartaric acid–NaBr-modified nickel catalyst

The effects of the modification conditions on the hydrogenation rate and the enantio-differentiating ability (e.d.a.) for the enantio-differentiating hydrogenation of methyl acetoacetate were studied over an (R, R)-tartaric acid–NaBr-in-situ-modified nickel catalyst. It was revealed that a tartaric acid modification increased the hydrogenation rate irrespective of the presence of the auxiliary modifier, NaBr. In the presence of the tartaric acid, NaBr would have two roles, i.e., Na⁺ activates the enantio-differentiating sites through the interaction with tartaric acid, and Br⁻ deactivates both the enantio-differentiating sites and non-enantio-differentiating sites. The e.d.a. values and the hydrogenation rate would be determined by the combination of these effects of Na⁺ and Br⁻.     

Selective formation of ethylene from CO2 by catalytic electrolysis at a three-phase interface

A new electrolysis system has been developed for the selective conversion of CO₂ to ethylene in which the electrochemical reduction takes place at the three-phase (gas/liquid/solid) interface on a Cu-mesh electrode mediated with copper(I) halide in an aqueous solution of potassium halide. The conversion percentage of CO₂ (initial volume: 577 cm³) reaches about 90% by the electrolysis with the electric charge of 8.9 kC, and the selectivity for C₂H₄ formation is about 75%. The selective conversion of CO₂ to C₂H₄ is attributed to the immobilized copper(I) halide which operates as a heterogeneous catalyst by offering adsorption sites for reduction intermediates such as CO and carbene.