No abstract

We present here the results of photocatalytic interface reactions between the catalysts shown in the title and acetic acid or alcohol (methanol, ethanol, and 2-propanol) in aqueous solution. Irrespective of loaded metal species in the platinum group, the same radical intermediates, a methyl radical CCH3) and a carboxymethyl radical eCH2COOH), were recognized by observation of their ESR absorption from aqueous solution of the acetic acid at room temperature. Moreover transient intermediates of a-hydroxymethyl radical (*CH2OH), -hydroxyethyl radical (CH3"CHOH), and -hydroxypropyl radical (CH3"COHCH3) were observed in reactions with organic ingredients of methanol, ethanol and 2-propanol, respectively. Our results suggest that a photocatalytic active site in the generation of the radical intermediates under UV illumination is not on the metal surface but the Ti02 surface of the photocatalysts. As a "preintermediate", existence of a hydroxyl radical ("OH) was presumed on the surface of the photocatalyst; the radical is created by electron transfer from a hydroxy anion (OH-) to an electron hole (p+) of Ti02.Thus, the most probable photocatalytic reaction mechanism has been proposed which indicates the resultant electron transfer from OH~to H+ over the photoexcited M/Ti02.

No abstract

The expression of the murine double minute-2 (MDM2) gene, the product of which binds to and inactivates p53, was studied in 60 patients with B-cell chronic lymphocytic leukemia (B-CLL) or non-Hodgkin's lymphoma (B-NHL). Northern blot analysis showed that the level of MDM2 gene expression was low in normal human B-cells, whereas 17 of the patients (28.3%) with B-CLL or NHL had more than 10-fold higher levels of MDM2 gene expression than that observed in normal B cells. Immunohistochemical analysis confirmed MDM2 overexpression at the cellular protein level. MDM2 gene overexpression was found more frequently in patients with the low-grade type of lymphoma (56.5%) than in those with intermediate-/high-grade types (10.8%) (P = .001). Moreover, MDM2 overexpression was found significantly more frequently in patients at advanced clinical stages. Simultaneous analysis of p53 gene mutation showed that three patients had both MDM2 gene overexpression and p53 gene mutation. The results of the present study suggest that MDM2 gene overexpression may play an important role in the tumorigenicity and/or disease progression of CLL and low-grade lymphomas of B-cell origin.

Soil organic carbon (SOC) is one of the important measures of soil fertility and sustainability in arable lands. With continuous CO 2 flux measurements, this study assessed the SOC decomposition and its environmental controls at both half-hourly and season-long scales in a single-crop rice (Oryza sativa L.) paddy during three fallow periods between 2004 and 2007. Measurements were made on a gray lowland soil sited in eastern Japan using the eddy covariance method. Ecosystem respiration was strongly affected by soil water content measured at 0-0Á1 m depth. At 0Á5 m 3 m À 3 or more of soil water content, the baseline of ecosystem respiration decreased by 50% compared with that at 0Á2 m 3 m À 3 . The effect was quantified at half-hourly scale using an empirical multiple regression model, together with the soil surface temperature and the time after residue incorporation. At season-long scale, net biome production, which is equivalent to the change in the SOC pool during the fallow period, was estimated from the flux and ancillary data at 150 g C m À 2 in 2004-2005, 70 g m À 2 in 2005-2006, and 270 g C m À 2 in 2006-2007. Apparently, as much as 46 to 79% of the soil organic matter incorporated (crop residues, ratoon, and stable manure) was decomposed during the fallow period. Precipitation, or associated soil water content, was important for the carbon balance of the field at season-long scale because of its large interannual variability and relatively low permeability of the paddy soil.