Characterization of an Ambient Coarse Particle Concentrator Used for Human Exposure Studies: Aerosol Size Distributions,Chemical Composition,and Concentration Enrichment

The goals of the experiments described herein involve determining in real time the size, concentration enrichment, and chemical composition of coarse-mode (<2.5 μm) and fine-mode (>2.5 μm) particles within the nonconcentrated and concentrated flows of a coarse particle concentrator used for human exposure studies. The coarse particle concentrator was intended to concentrate ambient particles in the PM_10–2.5 size range before sending them into a human exposure chamber. The aerodynamic size and chemical composition of particles in the upstream and downstream flows of the concentrator were monitored with an aerosol time-of-f1ight mass spectrometer (ATOFMS) for fixed time intervals over the course of three days. Based on the ATOFMS results, it was found that there was no change in the composition of the ten major particle types observed in the upstream and downstream flows of the concentrator under normal operating conditions. Furthermore, no new particle types were detected downstream that were not detected upstream of the concentrator. A characterization of the aerosol chemical composition and its dependence on sampling conditions is also discussed. Aerosol size distributions were measured with three aerodynamic particle-sizing (APS) instruments sampling simultaneously from different regions of the concentrator. The APS size distributions were used to scale ATOFMS data and measure the ambient concentration factors for the coarse particle concentrator and the exposure chamber. The average concentration factor (ratio of inlet number concentration to the outlet number concentration) for the particle concentrator was 60 + 17 for the 2.5–7.2 μm size range before dilution and transport to the exposure chamber. It was observed that not only were coarse particles being concentrated but fine (<2.5 μm) particles were being concentrated as well, with concentration factors ranging from 2–46 for aerodynamic particle sizes from 0.54–2.5 μm.     

Cardiovascular effects in patrol officers are associated with fine particulate matter from brake wear and engine emissions

Background  

Exposure to fine particulate matter air pollutants (PM_2.5) affects heart rate variability parameters, and levels of serum proteins associated with inflammation, hemostasis and thrombosis. This study investigated sources potentially responsible for cardiovascular and hematological effects in highway patrol troopers.     

Detection of a genetic alteration and species identification of coho salmon (Oncorhynchus kisutch): a collaborative study

A PCR-based method for the identification of genetically modified coho salmon (Oncorhynchus kisutch) has been developed and evaluated by a collaborative study. The coho salmon contained an "all-salmon" gene-construct (OnMTGH1) consisting of the metallothionein-B-promoter fused to the full-length type-1 growth hormone gene, both from sockeye salmon (Oncorhynchus nerka). Two PCRs were performed. The first PCR served as a control for amplifiable DNA present in the sample, and at the same time as a tool for species identification by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) test. For this PCR, universal primers located in the mitochondrial cytochrome b gene were used. The second PCR, working with primers located within the construct, detected the genetic alteration. In a collaborative study with 15 laboratories, in each case the species and the genetic modification had been assigned correctly.     

Dependence of in vitro biocompatibility of ionomeric cements on ion release

The in vitro biocompatibility of a group of ionomeric cements (ICs) was evaluated with respect to their ion release properties. These ICs were made from a defined series of glasses with the general formula 1.5SiO20.5P2O5Al2O3(1.0-Z)CaO0.75CaF2 where Z was the mole fraction (ranging from 0–0.1) of an alkali metal oxide, either sodium or potassium or a mixture of both. For these alkali metal ICs, the amount of sodium released was directly related to the sodium content of the constituent glass. Similarly, the amount of potassium released was directly related to the potassium content. There was no correlation between the aluminum content of the glass and the aluminum ion release. Increasing the monovalent cation concentration, however, produced ICs with increased fluoride release. The biocompatibility of the ICs, as assessed by in vitro cell growth and viability measurements, was inversely proportional to aluminum ion release. Fluoride ion release, although important in terms of in vitro biocompatibility, would appear to be less important than aluminum ion release in determining the overall biocompatibility of the ICs studied. © 1998 Kluwer Academic Publishers     

Evidential fusion of sensor data for activity recognition in smart homes

Advances in technology have provided the ability to equip the home environment with a layer of technology to provide a truly ‘Smart Home’. These homes offer improved living conditions and levels of independence for the population who require support with both physical and cognitive functions. At the core of the Smart Home is a collection of sensing technology which is used to monitor the behaviour of the inhabitant and their interactions with the environment. A variety of different sensors measuring light, sound, contact and motion provide sufficient multi-dimensional information about the inhabitant to support the inference of activity determination. A problem which impinges upon the success of any information analysis is the fact that sensors may not always provide reliable information due to either faults, operational tolerance levels or corrupted data. In this paper we address the fusion process of contextual information derived from uncertain sensor data. Based on a series of information handling techniques, most notably the Dempster–Shafer theory of evidence and the Equally Weighted Sum operator, evidential contextual information is represented, analysed and merged to achieve a consensus in automatically inferring activities of daily living for inhabitants in Smart Homes. Within the paper we introduce the framework within which uncertainty can be managed and demonstrate the effects that the number of sensors in conjunction with the reliability level of each sensor can have on the overall decision making process.     

Diffusion and sorption of nitroplasticizers in vinyl copolymer elastomer and its composites

To study the aging behavior of cured vinyl copolymer elastomer (VCE) under thermal and nitroplasticizer (NP) environment, we investigated the sorption and diffusion of NP in VCE and its composites. The sorption kinetics of NP into VCE and its composites with respect to filler concentration (0–80%) and temperature (18–70°C) were investigated by conventional gravimetric method. The NP sorption process is endothermic. Kinetic studies show that Fickian diffusion can describe the NP sorption in the VCE polymer. The samples with a high filler concentration show more complicated behavior at low temperature than that at high temperature. The present article discusses the dependences of diffusion coefficient and other related parameters on the polymer concentration and morphological structures of the samples. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40729.