Atmosphere of Wet Basements as a Novel Route for Potential Residential Exposure to 1,4-Dioxane Vapor.

Detection of 1,4-dioxane has been reported in shallow groundwater in neighborhoods of the city of Ann Arbor, Michigan. Michigan has a voluntary 1,4-dioxane shallow groundwater screening level based on its potential for vapor intrusion. Calculations show that if 1,4-dioxane-contaminated water were to enter a basement and evaporate, potentially unhealthy concentrations of 1,4-dioxane could arise in homes with damp basements under certain conditions.

Michigan's Gelman Site 1,4-Dioxane Groundwater Contamination: Still Spreading Decades after Detection.

Disposal practices of industrial wastewater by Gelman Sciences led to high concentrations of 1,4-dioxane in groundwater in Michigan, USA. Since discovery of off-site pollution in 1984, the contaminated groundwater prompted closure of over 124 private wells, closure of one municipal well, and prohibition of most groundwater uses in a large section of the city of Ann Arbor. Recent 1,4-dioxane detections in shallow groundwater in Ann Arbor and in township residential wells pose new exposure threats.

Operant psychology makes a splash--in marine mammal training (1955-1965).

Despite the wide spread use of operant conditioning within marine animal training, relatively little is known about this unique application of behavioral technology. This article explores the expansion of operant psychology to commercial marine animal training from 1955 to 1965, specifically at marine parks such as Marine Studios Florida, Marineland of the Pacific, Sea Life Park, and SeaWorld. The contributions of Keller and Marian Breland and their business Animal Behavior Enterprises (ABE) as well as other early practitioners of behavioral technology are reviewed.

Chemical activity as an integrating concept in environmental assessment and management of contaminants.

It is suggested that chemical activity in environmental media can serve as an integrating concept for holistic evaluations of contaminants, including their fate and effects. In support of this assertion, information underlying the thermodynamic principles and the relationships between monitored and modeled concentrations and activities are presented. The toxicological significance of activity is discussed, with emphasis on substances that exert baseline narcosis.

Sources and prevalence of pentachlorobenzene in the environment.

There are no longer any large scale uses of pentachlorobenzene (PeCB). Current emissions of PeCB to the environment are estimated to be about 121000kgy(-1), based on published information. The largest sources appear to be combustion of solid wastes, 32000kgy(-1), biomass burning, 45000kgy(-1) with degradation of an agricultural fungicide, quintozene, contributing 26000kgy(-1) and industrial releases less important.

Operant psychology goes to the fair: Marian and Keller Breland in the popular press, 1947-1966.

Marian and Keller Breland pioneered the application of operant psychology to commercial animal training during the 1940s and 1950s. The Brelands' story is relatively unknown in the history of behavior analysis. Using information from the Breland-Bailey papers, this paper describes the development and activities of Animal Behavior Enterprises (ABE), the Brelands' animal training business.

A new class of far-red and near-infrared biological labels based on alloyed semiconductor quantum dots.

Ternary cadmium selenium telluride quantum dots (CdSe(1-x)Tex, x = mole fraction of tellurium) have been prepared for potential use as constant-size biolabels with tunable fluorescence emission in the far-red and near-infrared (650-850 nm) spectral range. In contrast to particle size tuning reported for binary dots, we show that molar composition can be used to tune the optical and electronic properties of alloyed semiconductor nanocrystals without changing the particle size. A surprising finding is a nonlinear relationship between the composition and the absorption/emission energies, leading to new properties not obtainable from the parent CdSe and CdTe binary systems.

Hydrolytic stability of toluene diisocyanate and polymeric methylenediphenyl diisocyanate based polyureas under environmental conditions.

Polyureas were prepared by reacting toluene diisocyanate (TDI) or polymeric methylenediphenyl diisocyanate (PMDI) with water under prolonged vigorous mixing at room temperature. Hydrolytic degradation of these (powdered) TDI- and PMDI-based polyureas was studied by measuring the rates of formation of free toluenediamine (TDA) or methylenedianiline (MDA) in water as a function of time by utilizing HPLC. The heterogeneous hydrolysis reactions were carried out in glass reaction tubes under nitrogen with initial polyurea loadings of 2 g/L in deionized water or buffer solution.

Primary sources of selected POPs: regional and global scale emission inventories.

During the last decade, a number of studies have been devoted to the sources and emissions of Persistent Organic Pollutants (POPs) at regional and global scales. While significant improvements in knowledge have been achieved for some pesticides, the quantitative understanding of the emission processes and emission patterns for "non-pesticide" POPs are still considered limited. The key issues remaining for the non-pesticide POPs are in part determined by their general source classification.

Alloyed semiconductor quantum dots: tuning the optical properties without changing the particle size.

Alloyed semiconductor quantum dots (cadmium selenium telluride) with both homogeneous and gradient internal structures have been prepared to achieve continuous tuning of the optical properties without changing the particle size. Our results demonstrate that composition and internal structure are two important parameters that can be used to tune the optical and electronic properties of multicomponent, alloyed quantum dots. A surprising finding is a nonlinear relationship between the composition and the absorption/emission energies, leading to new properties not obtainable from the parent binary systems.

Fate and potential environmental effects of methylenediphenyl diisocyanate and toluene diisocyanate released into the atmosphere.

Information from a variety of sources has been collected and summarized to facilitate an overview of the atmospheric fate and potential environmental effects of emissions of methylenediphenyl diisocyanate (MDI) or toluene diisocyanate (TDI) to the atmosphere. Atmospheric emissions of both MDI and TDI are low, both in terms of concentration and mass, because of their low volatility and the need for careful control over all aspects of their lifecycle from manufacture through disposal. Typical emission losses for TDI are 25 g/t of TDI used in slabstock foam production.

Luminescent quantum dots for multiplexed biological detection and imaging.

Recent advances in nanomaterials have produced a new class of fluorescent labels by conjugating semiconductor quantum dots with biorecognition molecules. These nanometer-sized conjugates are water-soluble and biocompatible, and provide important advantages over organic dyes and lanthanide probes. In particular, the emission wavelength of quantum-dot nanocrystals can be continuously tuned by changing the particle size, and a single light source can be used for simultaneous excitation of all different-sized dots.