Saltwater intrusion in coastal aquifer ??? comparison between the CIP and MOC simulation technique

Proper management and evaluation of environmental effects for coastal groundwater aquifers require accurate estimation of salt and fresh water movement. For this we compare two numerical methods to study saltwater intrusion. The two numerical methods are the CIP (constrained interpolation profile) and the MOC (method of characteristics). The two numerical methods are used to solve the salt transport equation. The two methods are applied and compared to saltwater intrusion experiments for confined and unconfined aquifer case studies. It is found that for both cases, the CIP-method is superior in terms of calculation time while keeping an acceptable numerical accuracy.     

Total mercury intake from fish and shellfish by Japanese people

Elevated mercury concentrations have been reported in fish in recent years. Japanese people eat a great deal of raw fishes and shellfishes as “Sashimi” and “Sushi”. The action level of large predatory fish such as tuna with total mercury levels exceeding the Japanese maximum permitted limit of 0.4 ppm is exempted from regulation in Japan. Therefore, current total mercury intake from fish and shellfish of Japanese people is unknown. The purpose of this investigation was to estimate the total mercury intake from fish and shellfish. It was found that the mean total mercury concentration of 1.11 ppm in tuna of eatable base as Sashimi or Sushi was clearly higher than the normal level. The mean total mercury intake from fish and shellfish was 0.17mg per capita per week . According to the hypothesis that 75% of total mercury in fish and shellfish is methylmercury, the weekly intake of 0.13 mg as methylmercury was corresponding amount to about 74% of provisional tolerable weekly intake 0.17 mg of methylmercury set by the Welfare Ministry of Japan.     

Pharmacogenomics of the human ABC transporter ABCG2: from functional evaluation to drug molecular design

In the post-genome-sequencing era, emerging genomic technologies are shifting the paradigm for drug discovery and development. Nevertheless, drug discovery and development still remain high-risk and high-stakes ventures with long and costly timelines. Indeed, the attrition of drug candidates in preclinical and development stages is a major problem in drug design. For at least 30% of the candidates, this attrition is due to poor pharmacokinetics and toxicity. Thus, pharmaceutical companies have begun to seriously re-evaluate their current strategies of drug discovery and development. In that light, we propose that a transport mechanism-based design might help to create new, pharmacokinetically advantageous drugs, and as such should be considered an important component of drug design strategy. Performing enzyme- and/or cell-based drug transporter, interaction tests may greatly facilitate drug development and allow the prediction of drug–drug interactions. We recently developed methods for high-speed functional screening and quantitative structure–activity relationship analysis to study the substrate specificity of ABC transporters and to evaluate the effect of genetic polymorphisms on their function. These methods would provide a practical tool to screen synthetic and natural compounds, and these data can be applied to the molecular design of new drugs. In this review article, we present an overview on the genetic polymorphisms of human ABC transporter ABCG2 and new camptothecin analogues that can circumvent AGCG2-associated multidrug resistance of cancer.     

A fate model of pathogenic viruses in a composting toilet based on coliphage inactivation

A composting toilet using sawdust as a matrix has the potential to trap pathogens that might occasionally be contained in human feces. Therefore, care should be taken when handling the sawdust. It should also be noted that pathogenic viruses tend to have stronger tolerance than pathogenic bacteria. The fates of several species of coliphages, T4, , Q and MS2, in sawdust were investigated as a viral model. The fates of coliphages were significantly different among them, and they changed in response to temperature and the water content of the sawdust. As the results, T4 coliphage had the strongest tolerance and Q had the weakest one in sawdust. It was estimated the days required to decrease virus to a safe level based on a risk assessment. According to the rates of Q and T4, 15 days and 167 days were required respectively for a safe level of infection risk based on actually operated composting toilet condition. Thus, it was significantly different depending on the species and sawdust conditions.