Lead poisoning from an unexpected source in a 4-month-old infant

Childhood lead poisoning is characteristically a disease that occurs between the second and third years of life, generally resulting from the child's ingestion of lead-based paint or dust. However, lead poisoning may also appear in the first year of life. The case of a 4-month-old infant is reported in which the preparation of infant formula in a lead-soldered samovar (urn) resulted in venous blood lead levels as high as 46 microg/dl. The samovar had been brought into the United States by the parents while on a visit to Iran. The infant was placed on chelation therapy with parenteral CaNa2EDTA followed by oral meso-2,3-dimercaptosuccinic acid (DMSA) and d-penicillamine. This resulted in a rapid and substantial reduction in the blood lead level. Lead poisoning in infancy may have unusual etiologies such as in utero transmission of lead by lead-poisoned women. Because sources of lead poisoning in infancy may be unusual, a detailed environmental investigation may be necessary to identify the exact source. Children exposed to lead in the first 2 years of life have a special vulnerability to the neurotoxicity of lead, with the risk of enduring developmental handicaps. Continued public health initiatives to remove lead from the environment, in conjunction with routine lead screening of young children, will be key in meeting the goal of the Centers for Disease Control and Prevention to eliminate childhood lead poisoning by the year 2011.     

A Progressive Deployment Strategy for Cooperative Adaptive Cruise Control to Improve Trafc Dynamics

Cooperative adaptive cruise control(CACC)vehicles are intelligent vehicles that use vehicular ad hoc networks(VANETs)to share trafc information in real time.Previous studies have shown that CACC could have an impact on increasing highway capacities at high market penetration.Since reaching a high CACC market penetration level is not occurring in the near future,this study presents a progressive deployment approach that demonstrates to have a great potential of reducing trafc congestions at low CACC penetration levels.Using a previously developed microscopic trafc simulation model of a freeway with an on-ramp—created to induce perturbations and trigger stop-and-go trafc,the CACC system s efect on the trafc performance is studied.The results show signifcance and indicate the potential of CACC systems to improve trafc characteristics which can be used to reduce trafc congestion.The study shows that the impact of CACC is positive and not only limited to a high market penetration.By giving CACC vehicles priority access to high-occupancy vehicle(HOV)lanes,the highway capacity could be signifcantly improved with a CACC penetration as low as 20%.     

Orientation suppression in fibers spun from polymer melt blends

The addition of very small amounts of carefully selected polymers by melt blending has been found to radically change the flow properties at spinning of conventional polymers such as polyethylene terephthalate, nylon 66, and polypropylene. This has a large effect on spun properties, especially at high wind-up speeds. The additive polymers used have included liquid crystal polymers, polyethlene, polyethylene glycol, and nylon 66. A major phenomen is a considerable lowering of spun orientation, or wind-up speed suppression. In order to activate the non-liquid crystal polymers to achieve this effect special spinning conditions are necessary. The mechanism is viewed as being nonuniform extensional flow in a two-phase system and not molecular interaction.     

Experimental technique using FTIR to estimate IR optical properties at variable temperatures: application to PMDA-ODA polyimide thin films from 100 to 380 degrees C

An experimental technique is presented to measure reflectance at high sample temperature with respect to room temperature in the infrared using Fourier transform infrared fitted with a reflectometer. Sample temperature artifacts are accounted for by sequential measurements taken with the lamp source on and with the lamp source off. The sequential measurements are shown mathematically to correct for the modulation of sample and detector thermal emissions. Further, the technique is applied to a polyimide (PMDA-ODA) film on a layer of gold deposited on a thermally oxidized Si wafer. It is shown that the optical properties (index of refraction and extinction coefficient) remain relatively constant with temperature (from room temperature to 380 degrees C) in the 4000-6000 cm(-1) spectral region. The significant changes that occur with temperature are the change in thickness of the film and also the spectral properties in the 2000-4000 cm(-1) region. Also, by using a Lorentz oscillator model, it is shown that this method is able to discern that spectral features corresponding to the OH stretching bands at 3630 and 3470 cm(-1) show significant variation with increasing temperature.