502 What is MELC? Microemulsions are stable, isotropically clear solutions consisting of an oil (such as octane) and water stabilized by a surfactant and co-surfactant. To form such a mixture the interfacial tension between the oil and water has to be decreased by the addition of both a surfactant and a cosurfactant. Sodium dodecyl sulphate (SDS) is a common and widely used surfactant.1,2 Mediu...

Speciation of arsenic (As) in well water and contaminated soil in the blackfoot disease endemic area has been studied by extended X-ray absorption fine structural (EXAFS) spectroscopy in the present work. Experimentally, we found that arsenic in the well water possessed an As-O bond distance of 1.72 A with a coordination number (CN) of 4.3. In the blackfoot disease area, arsenic with a high oxi...

The cyclic nitramine explosives hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX) were examined in field and microcosm soil samples to determine their patterns of degradation and environmental fates. A number of analytical techniques, including solid-phase microextraction with on-fiber derivatization, gas chromatography-mass spectrometry, gas...

effects of temperature and percentage of organic modifier were studied on retention and selectivity in rp-hplc using solvation parameter model. the system constants were determined by multiple linear regression analysis from experimental values in the retention factor for a group of different solutes with known descriptors by computer using the program spss/pc. the experimental results showed t...

conclusions this method could be feasibly used for purification of large quantities of allicin from garlic extract. results semi-preparative hplc yielded a distinct peak with a retention time of 12.28 minutes. the purity (≥ 95%) and biological activity (p > 0.05) of purified allicin were comparable to the standard allicin. purified allicin produced same peak areas compared to the standard allic...

In case-control research where there are multiple case groups, standard analyses fail to make use of all available information. Multiple events case-control (MECC) studies provide a new approach to sampling from a cohort and are useful when it is desired to study multiple types of events in the cohort. In this design, subjects in the cohort who develop any event of interest are sampled, as well...