No abstract

Young red tilapias were exposed for 96 h to each one of 6 concentrations of the pesticide Diazinon in order to determine the pesticide's acute toxicity level. After the ascertaining the lethal concentration (LC50) at 96 h, a level 10 times lower was selected for the bioaccumulation study of the pesticide in male and female specimens exposed for 9 days. The elimination process was carried out for 10 days beginning right after the conclusion of the accumulation process. Analytical procedures were developed and used for the studies of acute toxicity and bioaccumulation of Diazinon in red tilapia. A lethal concentration [LC50 (96 h)] of 3.85 mg/L was found, and steady-state accumulation, at a concentration of 28.45 mg/kg, was reached at 7.72 days. In the elimination process a concentration of 0.29 mg/kg was found in tilapia tissue by the sixth day after the fish were moved to clean water, and it continued to decrease quickly toward nondetectable levels.

BACKGROUND: Ewing sarcoma (ES) was a malignant tumor of bone or soft tissue. One of the few risk factors for developing ES is race, with a higher incidence noted in populations of European rather than African or Asian ancestry. The goal of the current study was to evaluate racial and ethnic differences in presentation and overall survival (OS) among patients diagnosed with ES before age 40 years. METHODS: Data from the Surveillance, Epidemiology, and End Results database identified 1715 patients aged <40 years who were diagnosed with ES between 1973 and 2005. Racial and ethnic group differences were compared using chi‐square tests. OS was estimated by Kaplan‐Meier analysis and compared using log‐rank tests and Cox models. RESULTS: Black patients had significantly more soft‐tissue tumors compared with white non‐Hispanic patients (P <.0001). Asian and white Hispanic patients were found to have an intermediate frequency of soft‐tissue tumors that also differed from white non‐Hispanic patients (P <.0001). White Hispanic patients presented with a higher proportion of larger tumors compared with white non‐Hispanic patients (P = .042). Black patients tended to be older than white non‐Hispanic patients (P = .012). Sex, frequency of pelvic tumors, and metastatic status did not appear to differ by ethnicity or race. OS was found to differ according to race and ethnicity. Even after controlling for known confounders, OS was significantly worse for black, Asian, and white Hispanic patients compared with white non‐Hispanic patients (P = .0031, P = .0182, and P = .0051, respectively). CONCLUSIONS: Ethnic and racial differences in characteristics and outcomes of patients with ES do exist. Understanding the etiology of these differences will require further study. Cancer 2010. © 2010 American Cancer Society.

In the present work, known concentration of sulfite aqueous solutions in the presence and absence of gallic acid was measured to corroborate the validity of modified Monier-Williams method. Free and bound-sulfite was estimated by differential pulse voltammetry. To our surprise, the modified Monier-Williams method (also known as aspiration method) showed to be very inaccurate for free-sulfite, although suitable for bound-sulfite determination. The differential pulse approach, using the standard addition method and a correction coefficient, proved to be swift, cheap, and very precise and accurate.

A novel methodology for the synthesis of silicon oxide mesoporous materials has been developed using soft reaction conditions, unlike other synthesis conditions present in the literature. The synthesis involves the use of the lyotropic liquid crystals formed by mixing the surfactant hexadecyltrimethylazanium (CTAB), sodium nitrate as catalyst, water and tetraethyl orthosilicate (TEOS) as the inorganic precursor. The silicon oxide samples were characterized by high-resolution transmission electron microscopy (HRTEM) and EDX analysis. The specific surface area of the powder and the pore size were determined by the BET method and were found to be 587 m 2 /g and 2-4 nm, respectively. The point of zero charge (pzc) determination using a zeta-meter apparatus was 3.1 showing the acid character of the surface. The template mesoporous SiO 2 samples can be used to prepare composite electrodes containing active mixed oxides, e.g. for lithium-ion batteries.