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Drinking water utilities rely on samples collected from the distribution system to provide assurance of water quality. If a water contamination incident is suspected, samples can be used to determine the source and extent of contamination. By determining the extent of contamination, the percentage of the population exposed to contamination, or areas of the system unaffected can be identified. Using water distribution system models for this purpose poses a challenge because significant uncertainty exists in the contamination scenarios (e.g., injection location, amount, duration, customer demands, contaminant characteristics). This article outlines an optimization framework to identify strategic sampling locations in water distribution systems. The framework seeks to identify the best sampling locations to quickly determine the extent of the contamination while considering uncertainty with respect to the contamination scenarios. The optimization formulations presented here solve for multiple optimal sampling locations simultaneously and efficiently, even for large systems with a large uncertainty space. These features are demonstrated in two case studies.

The separation of oxygen from nitrogen using metal-organic frameworks (MOFs) is of great interest for potential pressure-swing adsorption processes for the generation of purified O2 on industrial scales. This study uses ab initio molecular dynamics (AIMD) simulations to examine for the first time the pure-gas and competitive gas adsorption of O2 and N2 in the M2(dobdc) (M = Cr, Mn, Fe) MOF series with coordinatively unsaturated metal centers. Effects of metal, temperature, and gas composition are explored. This unique application of AIMD allows us to study in detail the adsorption/desorption processes and to visualize the process of multiple guests competitively binding to coordinatively unsaturated metal sites of a MOF.

Caloric restriction is the only known method of increasing lifespan in laboratory animals. The present study was conducted as part of a larger investigation into the effect of caloric restriction on longevity of rhesus monkeys as a model for human aging. This study focused on the effects of caloric restriction and aging on measures of middle-ear function measured with tympanometry. Peak compensated static acoustic admittance (peak Y(tm)) tended to be reduced with aging. For tympanometric width (TW), the effect of age was significant with TW increasing with age. Males had a trend of narrower TW than females. A significant age by sex interaction indicated that TW for males stays relatively constant, whereas TW for females increases with age. The equivalent ear canal volume (V(ea)) was significantly larger in male monkeys than in female monkeys, and marginally larger for the control monkeys than for the caloric restricted monkeys. These results parallel many findings in middle-ear function in aging humans. Longitudinal studies are planned.

Menkes' syndrome is an X-linked recessive multisystem disease which is usually fatal prior to 5 years of age. Though originally felt to be a disorder of copper deficiency, it now appears to be a copper storage disease, with the observed defects resulting from inappropriate systemic copper distribution. Disorders in the metabolism of metallothionein, a metalloprotein involved in cellular copper transport, may be the primary defect in this syndrome. This review summarizes the relevant clinical and pathologic findings seen in this condition to date. It also describes some of the abnormalities in the metabolism of copper and metallothionein in these infants.

This study investigated the feasibility of a prerecorded speech threshold procedure that was used in a picture-pointing format, and was administered to Spanish-speaking children by non-Spanish-speaking clinicians. The derived Spanish word list was compared for equivalency to English spondees on a group of bilingual adults. The test, administered to 16 children ages three to six years, resulted in good agreement between SRT and pure-tone average. The test was found to be feasible, rapid, and reliable.