Electron exchange capacity of pyrogenic dissolved organic matter (pyDOM): complementarity of square-wave voltammetry in DMSO and mediated chronoamperometry in water.

Pyrogenic dissolved organic matter (pyDOM) is derived from black carbon, which is important in the global carbon cycle and other biogeochemical redox processes. The electron-exchange capacity (EEC) of pyDOM has been characterized in water using mediated chronoamperometry (MCA), which gives precise results under specific operational conditions, but the broader significance of these EECs is less clear. In this study, we described a novel but complementary electrochemical approach to quantify EECs of pyDOM without mediation using square-wave voltammetry (SWV) in dimethyl sulfoxide (DMSO).

Influence of Organic Ligands on the Redox Properties of Fe(II) as Determined by Mediated Electrochemical Oxidation.

Fe(II) has been extensively studied due to its importance as a reductant in biogeochemical processes and contaminant attenuation. Previous studies have shown that ligands can alter aqueous Fe(II) redox reactivity but their data interpretation is constrained by the use of probe compounds. Here, we employed mediated electrochemical oxidation (MEO) as an approach to directly quantify the extent of Fe(II) oxidation in the absence and presence of three model organic ligands (citrate, nitrilotriacetic acid, and ferrozine) across a range of potentials () and pH, thereby manipulating oxidation over a broad range of fixed thermodynamic conditions.

Spatial distribution and biogeochemistry of redox active species in arctic sedimentary porewaters and seeps.

Redox active species in Arctic lacustrine sediments play an important, regulatory role in the carbon cycle, yet there is little information on their spatial distribution, abundance, and oxidation states. Here, we use voltammetric microelectrodes to quantify the concentrations of redox-active species at high vertical resolution (mm to cm) in the benthic porewaters of an oligotrophic Arctic lake (Toolik Lake, AK, USA). Mn(II), Fe(II), O, and Fe(III)-organic complexes were detected as the major redox-active species in these porewaters, indicating both Fe(II) oxidation and reductive dissolution of Fe(III) and Mn(IV) minerals.

A three-dimensional parametric adult head model with representation of scalp shape variability under hair.

Modeling the shape of the scalp and face is essential for the design of protective helmets and other head-borne equipment. However, head anthropometry studies using optical scanning rarely capture scalp shape because of hair interference. Data on scalp shape is available from bald men, but female data are generally not available.

Comparison of univariate and multivariate anthropometric design requirements methods for flight deck design application.

Designing aircraft cockpits to accommodate the wide range of body sizes and shapes existing in the world population has always been a difficult problem for crew station engineers. There is no consensus on the best method for obtaining measurements for body forms that statistically represent the variation within a population. The aim of this research is to compare the two most commonly used anthropometric approaches for dimension specification and flight deck design: the boundary cases multivariate and the percentile univariate.

A durable and inexpensive pump profiler to monitor stratified water columns with high vertical resolution.

A pump profiling system for real time sample collection has been constructed for a cost of <$1000 (USD) and mated with a ship's rosette that has conductivity, temperature, depth (CTD) and other sensors. The system permits the collection of ~15 L of water in one minute without exposure to O from air for discrete sampling of chemical, microbial and other constituents as well as for real time analyses using sensors. We also coupled a shipboard voltammetry system with solid-state microelectrodes to detect dissolved O and HS.

Morphology of Modern Arrowhead Tips on Human Skin Analog.

Archery has experienced a recent resurgence in participation and has seen increases in archery range attendance and in children and young adults seeking archery lessons. Popular literature and movies prominently feature protagonists well versed in this form of weaponry. Periodic homicide cases in the United States involving bows are reported, and despite this and the current interest in the field, there are no manuscripts published on a large series of arrow wounds.

Current and Future Challenges in Group Therapy.

This article reviews changes and considers challenges in group therapy since AGPA's 50 anniversary 25 years ago. The authors acknowledge the many important changes that have occurred in research, theory, and practice in the last two and a half decades, but focus on four topics: treating trauma with cultural sensitivity; the impact of technology on groups; challenges for LGBTQ clients in group; and the future for psychodynamic groups. The authors review the literature and provide recommendations on how to address the challenges.

Achieving synergy between chemical oxidation and stabilization in a contaminated soil.

Eight in situ solidification/stabilization (ISS) amendments were tested to promote in situ chemical oxidation (ISCO) with activated persulfate (PS) in a contaminated soil. A 3% (by weight) dose of all ISS amendments selected for this study completely activated a 1.5% dose of PS within 3 h by raising temperatures above 30 °C (heat activation) and/or increasing pH above 10.

The effects of oral contraceptive use on muscle stiffness across the menstrual cycle.

Objective: To determine the effect of oral contraceptives (OC) on hamstring neuromechanics and lower extremity stiffness across the menstrual cycle (MC).

Design: Causal comparative.

Setting: Research laboratory.

Posttraumatic exogenous Nocardia endophthalmitis.

Purpose: To report a case of posttraumatic exogenous Nocardia endophthalmitis.

Design: Interventional case report.

Method: A 46-year-old man presented with counting fingers vision, severe eye pain, hypopyon, and an iris mass consistent with endophthalmitis following a penetrating injury to the left eye.

Perturbations of plasma cortisol and DHEA-S following discontinuation of cocaine use in cocaine addicts.

Changes in plasma levels of cortisol and dehydroepiandrosterone sulfate (DHEA-S) following cocaine discontinuation were assessed in hospitalized chronic cocaine users. Measurements were performed after 6, 9, 18 and 21 days of abstinence. Repeated measures ANOVAs revealed significant time effects for cortisol (P<0.