Mechanism of Methylene Blue Bleaching by Lipoxygenase

A lipid peroxidation reaction and methylene blue bleaching reaction are thought to proceed in the presence of methylene blue with linoleic acid as the substrate from the time lipoxygenase is added until methylene blue bleaching concludes. For 15 s after adding the lipoxygenase, neither the lipid peroxidation reaction nor the bleaching reaction occurred, but they both proceeded after that time period. The results suggested that hydroperoxide is first formed by the lipid peroxidation reaction, after which methylene blue specifically picks the hydrogen from the hydroperoxide 13-OOH isomers, and then the methylene blue is reduced.     

Wave venation in downward gas-liquid two-phase flow (part II,cluster analysis for huge waves and disturbance waves and characteristics of those waves)

Wave velocities and wave widths were determined using wave-vein analysis for a wide range of air and water flow rates. Cluster analysis by a K-mean algorithm was applied to the discrimination between huge and disturbance waves for the present experimental conditions. Individual waves discriminated by cluster analysis reasonably correspond to those recognized from the relation between wave velocity and wave width. Appearance flow conditions for liquid slug, huge and disturbance waves were clarified. The characteristics of wave velocity, wave width, and maximum liquid holdup for huge and disturbance waves are discussed. Comparison between liquid slug, huge wave and disturbance wave flow parameters reveals that there exist distinct differences in wave width of these waves. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25 (8): 511–521, 1996     

Low-Temperature Fabrication of Transparent Yttrium Aluminum Garnet (YAG) Ceramics without Additives

A carbonate precursor of yttrium aluminum garnet (YAG) with an approximate composition of NH₄AlY_0.6(CO₃)_1.9(OH)₂·0.9H₂O was synthesized via a coprecipitation method from a mixed solution of ammonium aluminum sulfate and yttrium nitrate, using ammonium hydrogen carbonate as the precipitant. The precursor precipitate was characterized using chemical analysis, differential thermal analysis/thermogravimetry, X-ray diffractometry, and scanning electron microscopy. The sinterability of the YAG powders was evaluated by sintering at a constant rate of heating in air and vacuum sintering. The results showed that the precursor completely transforms to YAG at ∼1000°C via the formation of a yttrium aluminate perovskite (YAP) phase. YAG powders obtained by calcining the precursor at temperatures of ≤1200°C were highly sinterable and could be densified to transparency under vacuum at 1700°C in 1 h without additives.     

Mixed-model assembly line scheduling using the Lagrangian relaxation technique

The increasing market demand for product variety forces manufacturers to design mixed-model assembly lines on which different product models can be switched back and forth and mixed together with little changeover costs. This paper describes the design and implementation of an optimization-based scheduling algorithm for mixed-model compressor assembly lines at Toshiba with complicated component supply requirements. A separable integer optimization formulation is obtained by treating compressor lots going through a properly balanced line as undergoing a single operation, and the scheduling goal is to delivery products just in time while avoiding possible component shortage. The problem is solved b y using Lagrangian Relaxation (LR). Several generic defects of LR leading to slow algorithm convergence are identified based on geometrical insights, and are overcome by perturbing/ changing problem parameters. Numerical testing shows that near-optimal schedules are efficiently obtained, convergence is significantly improved, and the method is effective for practical problems. The system is currently under deployment at Toshiba     

Two-Dimensional Thermal Stress Analysis in Adhesive Butt Joints Containing Hole Defects and Rigid Fillers in Adhesive Under Non-Uniform Temperature Field

This study is concerned with the thermal stress analysis of an adhesive butt joint which contains circular holes and rigid fillers in an adhesive and is under a non-uniform temperature field. In the analysis, the adherends are assumed to be rigid and the adhesive is replaced with a finite strip having holes and rigid fillers in it and the thermal stress distribution in the adhesive is analyzed using a two-dimensional theory of elasticity. The effects of size and location of the circular holes and rigid fillers on the stress distributions at the interface and at the hole and filler peripheries are clarified by numerical calculations. For verification, photoelastic experiments were performed using an epoxide resin plate with small holes and fillers in it, to model and adhesive in the joint. The analytical results are fairly consistent with the experimental ones.     

Development of X-ray dark-field imaging towards clinical application

Review of X-ray dark-field imaging under development is presented. Its goal is its application to clini-cal diagnosis of organs that have been invisible by the ordinary techniques. In order to clinically visualize tissues in detail one needs high contrast and high spatial resolution say～50μm. This X-ray optics comprises a Bragg asymmet-ric monochro-collimator and a Bragg case or a Laue case filter with capability of analyzing angle in a parallel posi-tion. Their diffraction index is 4,4,0 and the X-ray energy 35 keV (λ=0.0354 nm). The filter has 0.6 mm thickness in the Bragg case or 1.075 mm or 2.15 mm thickness in the Laue case. Under this condition only the refracted X-rays from object can transmit through the filter while the beam that may receive absorption and/or phase change will not.Soft tissues at human joints thus taken show high contrast images so that the DFI is promising for clinical diagnosis.Preliminary X-ray absorption images of another clinical candidates of ear bones are also shown.     

Steep fronts at transient recovery voltages appearing with the interruption of inrush currents of transformers

High lightning overvoltages do not appear in underground substations connected to transmission cables. Consequently, it is very important to thoroughly investigate switching overvoltages and to achieve rational insulation coordination for apparatus installed in such underground substations. This paper discusses the occurrence of steep fronts at transient recovery voltages (TRV) appearing at circuit breakers when the inrush currents of transformers are interrupted. Caused by a steep front at the TRV, reignitions occur at circuit breakers, resulting in the generation of high overvoltages with high frequencies. The overvoltages are among the highest switching overvoltages appearing at the terminal of a transformer. The authors clarified the mechanism of the generation of steep fronts at TRV by means of EMTP analysis, as well as by carrying out tests in a high‐power laboratory. © 2001 Scripta Technica, Electr Eng Jpn, 135(1): 24–32, 2001     

Mechanical Properties of Human Concentrated Growth Factor (CGF) Membrane and the CGF Graft with Bone Morphogenetic Protein-2 (BMP-2) onto Periosteum of the Skull of Nude Mice

Concentrated growth factor (CGF) is 100% blood-derived, cross-linked fibrin glue with platelets and growth factors. Human CGF clot is transformed into membrane by a compression device, which has been widely used clinically. However, the mechanical properties of the CGF membranes have not been well characterized. The aims of this study were to measure the tensile strength of human CGF membrane and observe its behavior as a scaffold of BMP-2 in ectopic site over the skull. The tensile test of the full length was performed at the speed of 2mm/min. The CGF membrane (5 × 5 × 2 mm³) or the CGF/BMP-2 (1.0 μg) membrane was grafted onto the skull periosteum of nude mice (5-week-old, male), and harvested at 14 days after the graft. The appearance and size of the CGF membranes were almost same for 7 days by soaking at 4 °C in saline. The average values of the tensile strength at 0 day and 7 days were 0.24 MPa and 0.26 MPa, respectively. No significant differences of both the tensile strength and the elastic modulus were found among 0, 1, 3, and 7 days. Supra-periosteal bone induction was found at 14 days in the CGF/BMP-2, while the CGF alone did not induce bone. These results demonstrated that human CGF membrane could become a short-term, sticky fibrin scaffold for BMP-2, and might be preserved as auto-membranes for wound protection after the surgery.     

Synthesis of Reactive Sulfur Species in Cultured Vascular Endothelial Cells after Exposure to TGF-β1: Induction of Cystathionine γ-Lyase and Cystathionine β-Synthase Expression Mediated by the ALK5-Smad2/3/4 and ALK5-Smad2/3-ATF4 Pathways

Transforming growth factor-β₁ (TGF-β₁) occurs at high levels at damage sites of vascular endothelial cell layers and regulates the functions of vascular endothelial cells. Reactive sulfur species (RSS), such as cysteine persulfide, glutathione persulfide, and hydrogen persulfide, are cytoprotective factors against electrophiles such as reactive oxygen species and heavy metals. Previously, we reported that sodium trisulfide, a sulfane sulfur donor, promotes vascular endothelial cell proliferation. The objective of the present study was to clarify the regulation and significance of RSS synthesis in vascular endothelial cells after exposure to TGF-β₁. Bovine aortic endothelial cells in a culture system were treated with TGF-β₁ to assess the expression of intracellular RSS, the effect of RSS on cell proliferation in the presence of TGF-β₁, induction of RSS-producing enzymes by TGF-β₁, and intracellular signal pathways that mediate this induction. The results suggest that TGF-β₁ increased intracellular RSS levels to modulate its inhibitory effect on proliferation. The increased production of RSS, probably high-molecular-mass RSS, was due to the induction of cystathionine γ-lyase and cystathionine β-synthase, which are RSS-producing enzymes, and the induction was mediated by the ALK5-Smad2/3/4 and ALK5-Smad2/3-ATF4 pathways in vascular endothelial cells. TGF-β₁ regulates vascular endothelial cell functions such as proliferation and fibrinolytic activity; intracellular high-molecular-mass RSS, which are increased by TGF-β₁, may modulate the regulation activity in vascular endothelial cells.     

Characterization of BAMO/NMMO Copolymers

The compositions and microstructures, thermolyses, and sensitivities of 3,3-bis(azidomethyl)oxetane (BAMO) copolymers with 3-nitratomethyl-3-methyloxetane (NMMO) were characterized. The molar ratios of monomers fed in the copolymerizations were: BAMO/NMMO = 8/2, 7/3, and 6/4. The observed compositions were 81/19, 68/32, and 60/40, respectively. The relative compositions of trade microstructures were also exactly the same as theoretical values. The copolymerization of BAMO with NMMO behaved like an ideal system in the sense that the copolymer has approximately the same composition as the monomer fed. The microstructures of copolymers were also randomly arranged. Poly BAMO showed side chain decomposition in the initial stage of the thermolysis, on the other hand, backbone decomposition controlled the thermolysis of poly NMMO. The BAMO units and the NMMO units appeared to decompose more or less independently of one another and retained their individual decomposition characteristics despite being copolymerized. However, the heat generated by the NMMO decomposition, which occurred at 40°C lower than that of BAMO. activated the reaction of BAMO. Poly B/N(7/3) showed very interesting characteristics in sensitivities, mechanical properties, and the heat of decomposition.