Photooxidative degradation of polyethylene containing flame retardants by monochromatic light

Photodegradation of incombustible polymer materials [high-density (HD) and low-density (LD) polyethylene (PE) containing 0.5 to 2.0 phr of decabromodiphenyl ether (DBDE) or tetrabromobisphenol A (TBA) as a flame retardant] were studied using an Okazaki Large Spectrograph (OLS). Samples were irradiated in air at 23°C with monochromatic light of wavelengths at 260, 280, 300, 320, 340, and 360 nm. Ultraviolet and Fourier transform infrared (FTIR) spectra were taken to estimate the chemical changes caused by photoirradiation. Molecular weight change was followed by gel permeation chromatography (GPC) measurements. It was found that the photostability of PE samples was reduced by the addition of flame retardants. The threshold wavelengths of photodegradation are 320 nm and 360 nm for PE–TBA samples and PE–DBDE samples, respectively. Main-chain scission is favored when the irradiation was carried out with the light of wavelength 300 nm for HDPE–DBDE and HDPE–TBA samples. The most effective irradiation wavelengths for crosslinking are found to be 300 nm and 280 nm for LDPE–DBDE and LDPE–TBA samples, respectively. 1995 John Wiley & Sons, Inc.     

Synthesis of KTiOPO4 (KTP) Thin Films Using Metallo-organics

Crack-free and highly transparent KTiOPO₄ (KTP) thin films were synthesized by the sol-gel method using a homogeneous precursor solution prepared from ("BuO)₂-P(O)(OH), Ti(OEt)₄, and KOEt in EtOH. Precipitated powders from the solution crystallized directly to KTP above 550°C. Polycrystalline KTP thin films were obtained at 600°C on various substrates. On NdAlO₃(100) substrates, KTP films with (101) and (240) preferred orientations were formed at 600°C. KTP films on glass substrates showed a refractive index of 1.75 and an absorption edge of 350 nm. KTP films exhibited the second harmonic generation of the 532 nm light on irradiaton with 1064 nm light.     

Effect of amorphous silica nanoparticles on in vitro RANKL-induced osteoclast differentiation in murine macrophages

Amorphous silica nanoparticles (nSP) have been used as a polishing agent and/or as a remineralization promoter for teeth in the oral care field. The present study investigates the effects of nSP on osteoclast differentiation and the relationship between particle size and these effects. Our results revealed that nSP exerted higher cytotoxicity in macrophage cells compared with submicron-sized silica particles. However, tartrate-resistant acid phosphatase (TRAP) activity and the number of osteoclast cells (TRAP-positive multinucleated cells) were not changed by nSP treatment in the presence of receptor activator of nuclear factor κB ligand (RANKL) at doses that did not induce cytotoxicity by silica particles. These results indicated that nSP did not cause differentiation of osteoclasts. Collectively, the results suggested that nanosilica exerts no effect on RANKL-induced osteoclast differentiation of RAW264.7 cells, although a detailed mechanistic examination of the nSP70-mediated cytotoxic effect is needed.     

Studies on drug-induced lipidosis: VII. Effects of bis-β-diethylaminoethylether of hexestrol,chloroquine, homochlorocyclizine,prenylamine, and diazacholesterol on the lipid composition of rat liver and kidney

4,4′-Bis (β-diethylaminoethoxy)-α,β-diethyldiphenylethane (DH), which had been shown to induce a type of lipidosis resembling Niemann-Pick disease, was given to rats at a dose of 20, 50, 100, and 150 mg/kg body weight per day for 1 or 2 weeks. An enlargement of the liver with marked increases in free cholesterol, total phospholipids, and phosphatidylinositol took place by administration of a larger dose. The increase in bis (monoacylglyceryl) phosphate (BMGP), which is peculiar to this kind of drug-induced lipidosis, was dependent upon the dose of the drug as well as the length of time. Similar changes were also observed in kidney. Among several other drugs tested, chloroquine and diazacholesterol brough on as much increase in BMGP as treatement with DH.     

Accumulation of acidic phospholipids in a case of hyperlipidemia with hepatosplenomegaly

The results of studies made on an adult patient with hepatosplenomegaly, hyperlipidemia and accumulation of acidic phospholipids in the liver are presented. Storage of a lipoid substance was demonstrated histologically in lymph nodes, the liver and the bone marrow. Lipid analysis of the biopsy specimen from the liver revealed marked elevations of free cholesterol and two classes of acidic phospholipids: phosphatidyl inositol and another one which was tentatively identified as lysobisphosphatidic acid. Electron microscopic examination showed cytoplasmic inclusions with concentrically laminated structure.