Wireless sensor network based system for underground chemical plume tracking, A

A real-time subsurface chemical plume monitoring and tracking system is being developed that uses wireless-sensor networking to automatically extract data from underground chemical sensors. This system is aimed at tracking plumes caused by the release of toxic chemicals and biological agents into the environment as a result of accidental spills and improper disposal. Current practice involves manual collection of samples from monitoring wells followed by laboratory analysis, an expensive process taking days to weeks; such a delay reduces the effectiveness of mitigation techniques as well. Virtual Sensor Networks (VSN), a novel resource efficient approach for sensor networking being developed to track the migrating underground plumes, will be applicable to a broad class of problems. Laboratory based experiments and simulations are in progress to demonstrate the feasibility of the approach for large-scale plume tracking.This research is supported in part by Army Research Office and the National Science Foundation.1st place, ISTeC Student Research Poster Contest (April 7, 2008)

Scalable Preparation and Differential Pharmacologic and Toxicologic Profiles of Primaquine Enantiomers

Hematotoxicity in individuals genetically deficient in glucose-6-phosphate dehydrogenase (G6PD) activity is the major limitation of primaquine (PQ), the only antimalarial drug in clinical use for treatment of relapsing Plasmodium vivax malaria. PQ is currently clinically used in its racemic form. A scalable procedure was developed to resolve racemic PQ, thus providing pure enantiomers for the first time for detailed preclinical evaluation and potentially for clinical use. These enantiomers were compared for antiparasitic activity using several mouse models and also for general and hematological toxicities in mice and dogs. (+)-(S)-PQ showed better suppressive and causal prophylactic activity than (−)-(R)-PQ in mice infected with Plasmodium berghei. Similarly, (+)-(S)-PQ was a more potent suppressive agent than (−)-(R)-PQ in a mouse model of Pneumocystis carinii pneumonia. However, at higher doses, (+)-(S)-PQ also showed more systemic toxicity for mice. In beagle dogs, (+)-(S)-PQ caused more methemoglobinemia and was toxic at 5 mg/kg of body weight/day given orally for 3 days, while (−)-(R)-PQ was well tolerated. In a novel mouse model of hemolytic anemia associated with human G6PD deficiency, it was also demonstrated that (−)-(R)-PQ was less hemolytic than (+)-(S)-PQ for the G6PD-deficient human red cells engrafted in the NOD-SCID mice. All these data suggest that while (+)-(S)-PQ shows greater potency in terms of antiparasitic efficacy in rodents, it is also more hematotoxic than (−)-(R)-PQ in mice and dogs. Activity and toxicity differences of PQ enantiomers in different species can be attributed to their different pharmacokinetic and metabolic profiles. Taken together, these studies suggest that (−)-(R)-PQ may have a better safety margin than the racemate in human

Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces

Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO2 thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 degrees C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value. (C) 2016 Elsevier B.V. All rights reserved

Electrical and complex dielectric behaviour of composite polymer electrolyte based on PEO, alumina and tetrapropylammonium iodide

In this study, the electrical, dielectric and morphological analysis of composite solid polymer electrolytes containing polyethylene oxide, alumina nano-fillers and tetrapropylammonium iodide are conducted. The temperature dependence of conductivity shows activation energy of 0.23, 0.20 and 0.29 eV for electrolytes containing 0, 5 and 15 wt.% alumina, respectively, when data fitted to the Arrhenius equation. These activation energy values are in good agreement with those determined from dielectric measurements. The result confirms the fact that conductivity is activated by both the mobility and the charge carrier density. The conductivity isotherms demonstrated the existence of two peaks, at 5 and 15 wt.% Al2O3 composition. The highest conductivity values of 2.4 × 10−4, 3.3 × 10−4 and 4.2 × 10−4 S cm−1 are obtained for the sample with 5 wt.% Al2O3 at 0, 12 and 24 °C, respectively, suggesting an enhancement of conductivity compared with that of alumina free samples