Changes in urinary enzyme activity and histochemical findings in experimental tubular injury induced by gold sodium thiomalate

To elucidate the renal injury induced by gold treatment, we administered various doses of gold sodium thiomalate (GST) to Wistar rats and investigated alterations in the urinary enzyme activity, gamma-glutamyl transpeptidase (gamma GTP) and N-acetyl-beta-glucosaminidase (NAG) activity, and histochemical change of enzymes, gamma GTP, alkaline phosphatase (ALP) and acid phosphatase (ACP) activity in the renal tissue. The single administration of a large dose of gold salts induced acute tubular necrosis and enzyme leakage was detected histochemically without damage to the glomerulus. After chronic administration of small doses of gold salts, the urinary gamma GTP activities gradually increased, but urinary NAG activities did not. These findings suggested that the change in urinary enzyme activities, which leaked from inside of brushborder or lysosome, indicated the degree or localization of tubular damage, because renal tubules were selectively injured by gold salts.     

Preparation of phosphorus-containing silica glass for radiotherapy by co-implantation of phosphorus and nitrogen ions

P-31 can be activated to -emitter P-32 with 14.3 days half-life by neutron bombardment. A chemically durable glass containing a large amount of phosphorus is believed to be useful for in situ irradiation of cancers. When they are subjected to neutron bombardment and injected around the tumor, they can irradiate directly a cancer without giving radiation to normal tissues. In this study, a pure silica glass was implanted with phosphorus and nitrogen ions by a dose of 5×10¹⁶ cm^-2 at 30 and 14 keV, respectively, and subjected to two-step heat treatments at 400°C in H₂ and then at 900°C in O₂. In the first step, phosphorus colloids were grown in the silica glass. In the second step, the colloids were encapsulated in a SiO₂–P₂O₅ glass film formed at their surfaces and the structural damage produced by ion implantation was healed. It is speculated that the implanted nitrogen forms silicon oxynitride in the glass, strengthening the silica network and suppressing the evaporation of phosphorus during heat treatment. The prepared glass did not dissolve phosphorus or silicon, even after soaking in distilled water at 95°C for 7 days, and hence is believed to be useful for radiotherapy of cancers.     

The top-bottom effect of a tilted thick specimen and its influence on electron tomography

We present the top-bottom effect (TBE) of a 5 microm thick amorphous specimen in a 3 MV ultrahigh voltage electron microscope (ultra-HVEM) and its influence on the quality of electron tomography (ET). The 40-nm gold particles on the top surface of the specimen tilted at different angles have been observed to be of poorer image quality than those on the symmetrical bottom surface obtained by tilting and turning over the specimen. The point spread function of the gold-particle images was calculated using the increment Wiener filter and the image-quality variation was then evaluated. The TBE is shown to become more remarkable with the increase of the effective thickness of the tilted specimen or the decrease of the magnification of the ultra-HVEM. The ET simulation indicates that the TBE may generate approximately 4% distortion in the radial direction of a reconstructed sphere model.     

Magnetoplumbite-Corundum Phase Equilibria in the System Sr─Fe─Al─O at 1100°C

The phase relations in the region of the Fe₂O₃- and Al₂O₃-rich sides of the quaternary system SrO─Fe₂O₃–Al₂O₃–B₂O₃ and the location of conjugation lines between magnetoplumbite solid solution SrO·(6 − x)Fe₂O₃·xAl₂O₃ and corundum (α-Fe₂O₃, α-Al₂O₃) phases were determined at 1100°C in air by using the flux-growth method based on the Ostwald ripening mechanism. Activity–composition relations and the lattice parameters along the magnetoplumbite solid solutions were also obtained.     

Viscoelastic characteristics of short fiber reinforced polybutylene terephthalate

Mechanics of Time-Dependent Materials - The mechanical characteristics of short-fiber-reinforced thermoplastics should be evaluated based on viscoelastic theory because of the time and temperature...     

Dynamic change of copper in fly ash during de novo synthesis of dioxins

Although many researchers have reported that copper chloride is an important catalyst that generates relatively large amounts of dioxins in heat experiments involving model fly ash, details on the behavior of copper during the process are still unavailable. In this study, we used in situ XANES experiments involving one type of real fly ash, which originated from a municipal solid-waste incinerator (MSWI), and two fly ash models to investigate the behavior of copper in fly ash at temperatures that are suitable for de novo synthesis, which is the major formation route for dioxins during waste incineration and thermal processes. Cupric compounds in real fly ash and model fly ash A(CuCl2.2H2O + activated carbon (AC) + boron nitride (BN)) were reduced to cuprous compounds or elemental copper at low temperatures. The changes in the Cu XANES spectra of real fly ash were similar to those of model fly ash A and those of an oxychlorination catalyst. In model fly ash B (CuO + AC + KCl + BN), CuO did not vary dramatically in the temperature range studied. In this study, we found strong evidence that oxychlorination, the key mechanistic step in the formation of dioxins, occurred in both real MSWI and model fly ash.