Vectec Solutions (United States)

Biological control is one of the methods available for control of Aedes aegypti populations. We used experimental microcosms to evaluate the effects of actual predation and predation risk by dragonfly larvae (Odonata) on larval development, adult longevity, and adult size of Ae. aegypti. We used six treatments: control, removal, variable density cues (Cues VD), fixed density cues (Cues FD), variable density predator (Predator VD), and fixed density predator (Predator FD) (n = 5 each). Predator treatments received one dragonfly larva. Cue treatments were composed of crushed Ae. aegypti larvae released into the microcosm. For the FD treatments, we maintained a larval density of 200 individuals. The average mortality of Ae. aegypti larvae in the Predator VD treatment was used as the standard mortality for the other treatments. Mosquitoes from the Predator VD and Cues VD treatments developed faster, and adults were larger and had greater longevity compared to all other treatments, likely due to the higher food availability from larval density reduction. High larval density negatively affected larval developmental time, adult size, and longevity. Males were less sensitive to density-dependent effects. Results from this study suggest that the presence of predators may lead to the emergence of adult mosquitoes with greater fitness, causing an overall positive effect on Ae. aegypti population growth rates.

Railroad operations are complex processes incorporating several different decisions in order to move a railcar from one location to another. These decisions are often made separately without the ability to easily understand the impact of one decision on another. For example, if a new train is added, and another removed, will the expected connections of the traffic from those trains to subsequent trains still be acceptable, will the network capacity still be sufficient, and will the yards be able to handle the changes in workload? The role of the network simulation capability is to allow analysts to understand how all these disparate pieces fit together, primarily in the context of evaluating operating plan designs and contingency planning.

Hypothermia has represented the foundation of organ preservation, since it was demonstrated that hypothermia reduces the metabolic needs of an organ. At approximately 4°C, the utilization of oxygen is only 5% of that at normothermia. The inability to supply oxygen lead to our current reliance on hypothermia. A new perfusate has been developed which can be used without traditional hypothermia. An increased PO2 is provided by a perfluorochemical emulsion (PFOB, Alliance Pharmaceutical Corp.). The available oxygen can be more effectively utilized because preservation at warmer temperatures (25°C & 32°C) means the cell membranes are in a more normal fluid state. We have demonstrated that kidneys can be preserved at warmer temperatures with stable flow dynamics, O2-consumption and diuresis for time periods of at least 18 hours. METHODS-Fifty canine and 40 bovine kidneys have been studied, at two temperatures (25°C & 32°C) for time periods ranging from 3 to 18 hours. The kidneys were pumped on a modified Mox-100 at mean pressures ranging from 60-90 mmHg, resulting in vascular flow rates of 80-150cc/min. The renal perfusions were conducted at PO2 of 170–185 Torr to deliver oxygen at 7.7m1/min. RESULTS-The kidneys pumped at 25°C and 32°C demonstrated stable flow dynamics and diuresis for time periods of at least 18 hours. The renal metabolism occurring at the two temperatures was monitored as described below.

The world-wide shortage of organs for clinical transplantation is caused by the limited existing donor pool of heartbeating cadavers. Attempts to expand into the nonheartbeating cadaver population have been hindered by warm ischemic damage. We evaluated if a new Oxygent (Alliance Pharmaceutical Corp.) supplemented perfusate could be used to salvage canine kidneys postmortem. The kidneys preserved in the Oxygent perfusate could be maintained in situ for time points ranging from one-eight hours postmortem; enough time to declare death and obtain consent for organ donation. In contrast, the control kidneys yielded abnormal histologic findings and impaired flow dynamics. These results suggest that new perfusate may have significant potential to expand the existing organ donor pool.