Implementing an Environmental Contaminants Deliberation Module in General Chemistry.

Placing chemistry in the context of complex societal issues is one way to help students see the application of fundamental ideas in the general chemistry curriculum. Here, we describe the impact of an in-class deliberation on environmental contaminants, which encourages students to consider different perspectives when addressing the issue of water and soil quality in communities. Student surveys were used to analyze the quality of the deliberation and several key factors regarding student attitudes before and after the activity.

Improved hydrophobic subtraction model of reversed-phase liquid chromatography selectivity based on a large dataset with a focus on isomer selectivity.

Reversed-phase (RP) liquid chromatography is an important tool for the characterization of materials and products in the pharmaceutical industry. Method development is still challenging in this application space, particularly when dealing with closely-related compounds. Models of chromatographic selectivity are useful for predicting which columns out of the hundreds that are available are likely to have very similar, or different, selectivity for the application at hand.

Characterization of a high throughput approach for large scale retention measurement in liquid chromatography.

Many contemporary challenges in liquid chromatography-such as the need for "smarter" method development tools, and deeper understanding of chromatographic phenomena-could be addressed more efficiently and effectively with larger volumes of experimental retention data than are available. The paucity of publicly accessible, high-quality measurements needed for the development of retention models and simulation tools has largely been due to the high cost in time and resources associated with traditional retention measurement approaches. Recently we described an approach to improve the throughput of such measurements by using very short columns (typically 5 mm), while maintaining measurement accuracy.

Development of tandem-column liquid chromatographic methods for pharmaceutical compounds using simulations based on hydrophobic subtraction model parameters.

The liquid chromatography (LC) analysis of small molecule pharmaceutical compounds and related impurities is crucial in the development of new drug substances, but developing these separations is usually challenging due to analyte structural similarities. Tandem-column LC (TC-LC) has emerged as a powerful approach to achieve alternative separation selectivity compared to conventional single column separations. However, one of the bottlenecks associated with use of tandem column approaches is time-consuming column pair screening and selection.

Paleoclimate-induced stress on polar forested ecosystems prior to the Permian-Triassic mass extinction.

The end-Permian extinction (EPE) has been considered to be contemporaneous on land and in the oceans. However, re-examined floristic records and new radiometric ages from Gondwana indicate a nuanced terrestrial ecosystem response to EPE global change. Paleosol geochemistry and climate simulations indicate paleoclimate change likely caused the demise of the widespread glossopterid ecosystems in Gondwana.

Improvements in the predictive accuracy of the hydrophobic subtraction model of reversed-phase selectivity.

The hydrophobic subtraction model (HSM) for characterizing the selectivity of reversed-phase liquid chromatography (LC) columns has been used extensively by the LC community since it was first developed in 2002. Continuing interest in the model is due in part to the large, publicly available set of column descriptors that has been assembled over the past 18 years. In the work described in this report, we sought to refine the HSM with the goal of improving the predictive accuracy of the model without compromising its physico-chemical interpretability.

Simulation of elution profiles in liquid chromatography - II: Investigation of injection volume overload under gradient elution conditions applied to second dimension separations in two-dimensional liquid chromatography.

An important research direction in the continued development of two-dimensional liquid chromatography (2D-LC) is to improve the detection sensitivity of the method. This is especially important in applications where injection of large volumes of effluent from the first dimension (D) column into the second dimension (D) column leads to severe D peak broadening and peak shape distortion. For example, this is common when coupling two reversed-phase columns and the organic solvent content of the D mobile phase overwhelms the D column with each injection of D effluent, leading to low resolution in the second dimension.

Statistical analysis of the photodegradation of imazethapyr on the surface of extracted soybean (Glycine max) and corn (Zea mays) epicuticular waxes.

The photodegradation rate of the herbicide imazethapyr on epicuticular waxes of soybean and corn plants was investigated. Plant age, relative humidity, temperature, and number of light banks were varied during plant growth, analyzed statistically, and examined to determine if these factors had an effect on the photodegradation of imazethapyr. Through ultraviolet/visible (UV-Vis) and fluorescence spectroscopy, epicuticular wax characteristics of soybean and corn plants were explored, were used to confirm observations determined statistically, and explain correlations between the rate constants and the composition of the epicuticular waxes.

Simulation of elution profiles in liquid chromatography-I: Gradient elution conditions, and with mismatched injection and mobile phase solvents.

High-performance liquid chromatography (HPLC) simulators are effective method development tools. The goal of the present work was to design and implement a simple algorithm for simulation of liquid chromatographic separations that allows for characterization of the effect of injection solvent mismatch and injection solvent volume overload. The simulations yield full analyte profiles during solute migration and at elution, which enable a thorough physical understanding of the effects of method variables on chromatographic performance.

Youth experiences with multiple types of prejudice-based harassment.

Despite prejudice-based harassment's associations with serious physical and mental health risks, research examining multiple forms of harassment among children/adolescents is lacking. This study documents the prevalence of prejudice-based harassment (i.e.

Enhanced spatial resolution on figures versus grounds.

Much is known about the cues that determine figure-ground assignment, but less is known about the consequences of figure-ground assignment on later visual processing. Previous work has demonstrated that regions assigned figural status are subjectively more shape-like and salient than background regions. The increase in subjective salience of figural regions could be caused by a number of processes, one of which may be enhanced perceptual processing (e.