Tea catechins modulate the glucose transport system in 3T3-L1 adipocytes

In this study, we investigated the effects of tea catechins on the translocation of glucose transporter (GLUT) 4 in 3T3-L1 adipocytes. We found that the ethyl acetate fraction of green tea extract, containing abundant catechins, most decreased insulin-induced glucose uptake activity in 3T3-L1 cells. When the cells were treated with 50 μM catechins in the absence or presence of insulin for 30 min, nongallate-type catechins increased glucose uptake activity without insulin, whereas gallate-type catechins decreased insulin-induced glucose uptake activity. (-)-Epicatechin (EC) and (-)-epigallocatechin (EGC), nongallate-type catechins, increased glucose uptake activity in the dose- and time-dependent manner, whereas (-)-catechin 3-gallate (Cg) and (-)-epigallocatechin 3-gallate (EGCg), gallate-type catechins, decreased insulin-induced glucose uptake activity in the dose- and time-dependent manner. When the cells were treated with 50 μM catechins for 30 min, EC and EGC promoted GLUT4 translocation, whereas Cg and EGCg decreased the insulin-induced translocation in the cells. EC and EGC increased phosphorylation of PKCλ/ζ without phosphorylation of insulin receptor (IR) and Akt. Wortmannin and LY294002, inhibitors for phosphatidylinositol 3'-kinase (PI3K), decreased EC- and EGC-induced glucose uptake activity in the cells. Cg and EGCg decreased phosphorylation of PKCλ/ζ in the presence of insulin without affecting insulin-induced phosphorylation of IR, and Akt. Therefore, EC and EGC promote the translocation of GLUT4 through activation of PI3K, and Cg and EGCg inhibit insulin-induced translocation of GLUT4 by the insulin signaling pathway in 3T3-L1 cells.     

Sweet and bitter constituents of Wilbrandia species

Two novel cucurbitane glycosides, wilbrandisides A and B were isolated as sweet-taste substances from the root of Wilbrandia species (Cucurbitaceae) along with seven known cucurbitane glycosides. Their structures were determined by spectroscopic means, including two-dimensional NMR experiments. Their sweet-taste properties were evaluated by a human sensory panel test. Consequently, wilbrandiside A was shown to be 28 times sweeter than sucrose and was the compound having the most potent sweet taste of all the cucurbitane glycosides isolated from this plant.     

A Thin Carbon‐Fiber Web as a Scaffold for Bone‐Tissue Regeneration

Due to the rapid progress being made in tissue regeneration therapy, biomaterials used as scaffolds are expected to play an important role in future clinical application. We report the development of a 3D web (sheet) consisting of high‐purity carbon fibers in a nanoscale structure. When the thin carbon‐fiber web (TCFW) and recombinant human bone morphogenetic protein 2 (rhBMP‐2) composite is implanted in the murine back muscle, new ectopic bone is formed, and the values of the bone mineral content and bone mineral density are significantly higher than those obtained with a collagen sheet. Observation of the interface between the carbon fibers and bone matrix reveal that the fibers are directly integrated into the bone matrix, indicating high bone‐tissue compatibility. Further, the rhBMP‐2/TCFW composite repairs a critical‐size bone defect within a short time period. These results suggest that the TCFW functions as an effective scaffold material and will play an important role in tissue regeneration in the future.     

Calcium phosphate coating formed in infusion fluid mixture to enhance fixation strength of titanium screws

A novel technique was developed to coat a calcium phosphate (CaP) layer on titanium screws with a titanium oxide surface layer, using infusion fluids officially approved for clinical use. A calcium-containing solution, a phosphate-containing solution, and a sodium bicarbonate solution prepared from the infusion fluids were mixed at a Ca/P molar ratio of 2.0. Each screw was immersed in 10 mL of the resulting mixture at 37 °C for 2 days. A low-crystalline apatite layer (Ca/P molar ratio = 1.681 ± 0.038) was formed on the screws. The layer consisted of a few 100 nm diameter particles fixed on the screw surface. In animal experiments, the screws were percutaneously implanted in both proximal tibial metaphyses of rabbits. The insertion torque was not significantly different between the CaP-coated screws (0.132 ± 0.002 Nm, n = 10) and uncoated screws (0.140 ± 0.002 Nm, n = 10) (p = 0.5785). After the insertion torque test, the apatite layer remained on the surface of the screws, which means that the apatite layer survived the friction of screw insertion. The extraction torque of the screws in the CaP-coated group (0.239 ± 0.066 Nm, n = 19) was significantly higher (by 29.9%) than that in the uncoated group (0.184 ± 0.062 Nm, n = 18) 4 weeks after the operations (p = 0.0132). Histologically, a larger amount of new bone formation was observed around the CaP-coated screws than that around the uncoated screws. Even after the removal of the screw, the CaP layer remained on the screw at the site where soft tissues were attached. The coating technique with the use of the infusion fluids is an effective method of improving bone-screw interface strength.     

Accelerated Aging of Plateau Burn Composite Propellant

Effects of accelerated aging at 60 °C on combustion characteristics, thermal decomposition, and mechanical properties of high burn rate composite propellant were studied in this paper. Although less change in burn rate was observed until aging period of two weeks, approximately 7% decrease was obtained at a pressure range from 9 MPa to 14 MPa after 32 weeks aging. The pressure range of the plateau-mesa burning was shifted to higher pressure region by the aging. Although heat of decomposition measured by DSC decreased only 2% in the value, activation energy of thermal decomposition decreased 11%, from 133.3 kJ/mol to 119.5 kJ/mol. Increased CO₂ and decreased HCN were also observed in the gaseous product distribution. Iron catalyzed processes involving AP and binder decomposition products were altered with a time of aging and it might generate the plateau burning pressure range shift. The sample kept 32 weeks, however, did not show any significant changes in mechanical properties.     

Preparation and Properties of Woodceramic Thin Films

Woodceramic thin films were prepared onto alumina sheet and glass slide substrates by conventional radio frequency sputtering in an argon plasma. A woodceramic disk, 100 mm in diameter, sintered at 850°C was used as a target. The deposition rate was about 90 nm/h for 200 W input power. Remarkable differences were observed in the characteristics of films depending on the substrate temperature. Films prepared below 100°C had insulating properties, > 106 cm, and had transmission in the visible region ( > 600 nm), and had smooth surfaces. Increasing the substrate temperature causes sharp a decrease in the film resistivity and the growth of grain was 3–5 m. The film prepared at 300°C had semiconductor characteristics with an energy gap of about 0.05 eV.     

Regeneration of granular activated carbon with adsorbed trichloroethylene using wet peroxide oxidation

The objective of this study is to clarify the regeneration of granular activated carbon (GAC) adsorbed trichloroethylene (TCE) using wet peroxide oxidation (WPO). TCE and TOC concentrations decreased during WPO, whereas Cl(-) accumulated in water indicating that TCE was not only decomposed but was also mineralized to Cl(-) and CO(2) using WPO. Regeneration efficiencies (q/q(0)) of GAC regenerated at 150, 165 and 180 degrees C (initial pH 4) were 0.36, 0.45, 0.48, respectively. In addition, regeneration efficiencies of GAC regenerated in the solution of various initial pH (2.5, 3.0, 4.0) at 180 degrees C were 0.71, 0.60, 0.48, respectively. These results suggest that regeneration of GAC is more effective at higher reaction temperature and lower initial pH of the solution. In the repeated regeneration of GAC, the adsorption capacity of GAC for TCE gradually decreased and regeneration efficiency of the regenerated GAC at sixth step was 0.40. The adsorption capacity loss of regenerated GAC is probably due to oxidation of GAC during WPO.     

Novel interconnection method using electrically conductive paste with fusible filler

A new class of electrically conductive adhesives (ECAs) was developed using fusible filler particles. Differential scanning calorimetry (DSC) was used to examine the curing behavior of the base resin material and the melting behavior of the filler particles. The formation of the interconnection before and after the curing process was observed by means of a microfocus x-ray system. The cross-sectional morphology of the electrical conduction path was investigated by optical microscopy. It is believed that the wetting and coalescence behavior of the molten filler particles are the main driving forces leading to the production of the interconnection between the electrodes. In addition, the metallurgical connections both between the particles and between the particles and the copper substrate were observed using scanning electron microscopy and electron probe microanalysis (EPMA).