Heteroaggregation of nanoparticles with naturally occurring colloids has been shown to be an important process in nanoparticle fate and transport in the aquatic environment. The advent of a functional assay to measure heteroaggregation attachment efficiencies has opened the door for further mechanistic studies. It is well known that natural organic...
This study investigates the relationship between total and ionic copper in samples taken from the Tualatin River and wastewater treatment facilities (WWTFs) that discharge into the Tualatin River. Copper speciation was analyzed by determining conditional stability constants and densities of copper binding ligands on the dissolved organic matter (DOM) in...
Low concentrations of dissolved copper have proven to be harmful to a number of aquatic organisms, with recent research highlighting detrimental effects to endangered salmonid species. Stormwater runoff can represent a significant source of copper to surface waters, necessitating cost-effective alternatives to current stormwater best management practices (BMPs). This study...
Nanoparticles are becoming increasingly important in numerous technological fields but evidence shows that they can be toxic to many organisms. To predict their fate and transport in the environment, nanoparticle attachment to naturally occurring colloids must be examined. This study investigated citrate-capped gold nanoparticle (Cit-AuNP) heteroaggregation with two model colloids...
Understanding the aggregation behavior of engineered nanomaterials (ENMs) in aqueous environments is essential to understanding their fate, transport, and toxicity. Because naturally occurring colloids will likely be present at much higher concentrations than ENMs in environmental systems, heteroaggregation and attachment with these natural colloids could significantly influence ENM fate and...
Current best management practices (BMPs) for stormwater treatment are not able to adequately remove heavy metals to levels which do not adversely affect aquatic life. Copper is commonly found in highway stormwater runoff, with the primary source being brake pad wear. Copper is of particular concern due to inhibitory effects...
Copper and zinc are heavy metals commonly present in highway stormwater runoff. Discharge of these metals to surface waters inhabited by sensitive aquatic species including threatened and endangered salmonids has necessitated the need for improved treatment techniques. Although copper is of the greater toxicological concern, zinc is often present at...
Coagulation and flocculation are commonly used in drinking water treatment
as a means of destabilizing and aggregating particles and promoting adsorption of
dissolved organic carbon (DOC). In practice, jar tests are used to determine optimal
conditions for the removal of turbidity and DOC. However, beyond the inferences
that can be...
Low levels of copper have been shown to impair the olfactory system of threatened and
endangered (T&E) salmon, decreasing their predator avoidance behavior and likely
increasing mortality. However, only dissolved copper (dissCu) present as the cupric ion
(Cu2+) and weakly complexed species are truly bioavailable. Previous studies indicate the
vast...
The purpose of this research was to measure the copper-binding behavior of Dissolved Organic Matter (DOM) contained in Pulp and Paper (P&P) wastewater effluent and evaluate the Biotic Ligand Model’s (BLM) ability to quantify copper speciation in P&P influenced waters. A copper ion selective electrode was used to measure copper...
In order to better predict the aggregation state of nanomaterials, the factors that influence aggregation must be understood. The combined effects of natural and engineered coatings have been shown to factor into nanoparticle aggregation behavior in preliminary research. In this study, aggregation behaviors of gold nanoparticles with two different engineered...
The adsorption of natural organic matter (NOM) to the surfaces of natural colloids
and engineered nanoparticles is known to strongly influence, and in some cases control,
their surface properties and aggregation behavior. As a result, the understanding of
nanoparticle fate, transport and toxicity in natural systems must include a fundamental...
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JeffreyA. Nason
The adsorption of natural organic matter (NOM) to the surfaces of
The purpose of this investigation was to determine the validity and
reliability of the Nicholas Manual Muscle Tester (NMMT), a portable
dynamometer, as a measure of the isometric strength in women with arthritis.
Female subjects (N=13; 66 ± 13.89 yrs.) with arthritis were tested for
isometric muscle strength on the...
The purpose of this study was to compare the levels of bone
mineral density (BMD) of the whole body (WB) and proximal
femurs of physically active men with spinal cord injuries (SCI) to
nonactive men with spinal cord injuries. Also, the lean muscle
mass (LMM) of active men with SCI...
Balance is the ability to establish an equilibrium between the body and its environment. Balance is a key component which is associated with a variety of movements and postural control. Children with cerebral palsy (CP) have difficulties with movement and postural control due to physical and neurological limitations. The purpose...
The purpose of this study was to determine if a 5-month
progressive-resistance exercise program would affect measures
of activities of daily living (ADLs) and functional stability
in elderly women. All subjects were ambulatory women, 80 to
93 years old, who lived in assisted-care facilities. Eight
exercise and 7 control subjects...
Logging and forest thinning operations generate large amounts of residues in the form of small trees, branches and foliage that are usually left on the ground to decay or are burned. These resources are readily available, but it is uneconomical to remove them from the forest. The potential utilization of...