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Four quantitative structure-activity relationships were developed for toxicity of selected photosynthesis (PHS) inhibitors and acetolactate synthase (ALS) inhibitors to Chlorella Vulgaris and Raphidocelis subcapitata using a mechanism-based approach. These models have good fitness and predictive ability. The potential of electron transfer, intermolecular interactions with weak electron-transfer, and intermolecular dispersive interactions between PHS inhibitors and the active site of action are key factors influencing the toxicity of these PHS inhibitors. Intermolecular weak electron-transfer interactions and intermolecular dispersive interactions mainly determine the toxicity of these ALS inhibitors. Sulfonyl is an important functional group governing the toxicity of ALS inhibitors investigated. [ABSTRACT FROM AUTHOR]

Owing to the importance of octanol--air partition coefficients (KOA) in describing the partition of organic pollutants from air to environmental organic phases, the paucity of KOA data at different environmental temperatures, and the difficulty or high expenditures involved in experimental determination, the development of predictive models for KOA is necessary. Approaches such as this are greatly needed to evaluate the environmental fate of the ever-increasing list of production chemicals. Partial least squares (PLS) regression with 18 molecular structural descriptors was used to develop predictive models based on directly measured KOA values of selected chlorobenzenes, polychlorinated biphenyls (PCBs), polychlorinated naphthalenes, polychlorinated dibenzo-pdioxins/ dibenzofurans, polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons, and organochlorine pesticides (OPs). An optimization procedure resulted in two temperature-dependent universal predictive models that explained at least 91% of the variance of log KOA. Model 1 was the more general of the two models that could be used for all the persistent organic pollutant (POP) classes investigated. Although model 1 performed poorly for select OPs, this was attributed to wide variability in structural types within this subset of POPs and their diversity compared to the other POP classes that were investigated. The exclusion of the structurally complex OP subset resulted in a more precise model, model 5. Intermolecular dispersive interactions (induced dipole--induced dipole forces) between octanol and solute molecules play a decisive role in governing KOA and its temperature dependence. Further investigations are needed to better characterize the steric structures of the POPs under study, especially of OPs. [ABSTRACT FROM AUTHOR]

Studies the active species and catalytic properties of CuO/CeO2-TiO2 catalysts for NO+CO reaction. Determination of the surface area of catalysts; Performance of gas chromatography using a thermal conductivity detector; Examination of the structural properties of titanium dioxide.

Background/aims: To evaluate the benefits of the tumor thrombus types system on determining treatments and prognosis of hepatocellular carcinoma patients (HCC) with tumor thrombi in the portal vein., Methodology: According to anatomic features of the portal vein in the liver and tumor thrombus of HCC developing modes, a uniform tumor thrombus types system (types I-IV) was first recommended. 84 HCC patients with portal vein tumor thrombi, which from January 2000 to January 2003 in the Eastern Hepatobiliary Surgery Hospital, were divided into I-IV groups according to types I-IV of the tumor thrombus system. The median survival periods and effectiveness of surgical resection or non-resection for I-IV groups were retrospectively observed., Results: The median survival periods for patients of group I (n=17), II (n=26), III (n=35) and group IV (n=6) were 10.1, 7.2, 5.7 and 3.0 months, respectively (p = 0.0001). From tumor thrombus type I to type III, the patients received surgical resection were better than that of non-resection (P = 0.0006). Among the patients receiving resection treatment, resection of tumor thrombus type I had the best effects, while for patients with tumor thrombus type IV, the results were not good. In case of non-resection treatments, the survival periods of patients with tumor thrombi type I, II and III were similar, which supposed that TACE may be of little effects on tumor thrombi., Conclusions: Types of tumor thrombus system suggested may be helpful to determine the treatments and prognosis of HCC patients with tumor thrombi in the portal vein.