John A. Pickrell

Nanocrystalline titanium dioxide and magnesium oxide in vitro dermal absorption in human skin

The dermal absorption potential of a nanocrystalline magnesium oxide (MgO) and titanium dioxide (TiO2) mixture in dermatomed human skin was assessed in vitro using Bronaugh-type flow-through diffusion cells. Nanocrystalline material was applied to the skin surface at a dose rate of  50 mg/cm2 as a dry powder, as a water suspension, and as a water/surfactant (sodium lauryl sulfate) suspension, for 8 hours. Dermal absorption of nanocrystalline MgO and TiO2 through human skin with intact, functional stratum corneum was not detectable under the conditions of this experiment.

Examining the risks and benefits of replacing traditional dose-response with hormesis.

In responding to Drs Calabrese and Baldwins question, ‘At what point, if ever, should hormesis be employed as the principal dose response default assumption in risk assessment?’, we examined the benefits of replacing traditional dose-response with hormesis. In general, hormesis provides more complete useful information for risk assessment than does traditional dose-response. A major limitation of using hormesis as a default assumption in risk estimation is the difficulty of differentiating complex low-level hormetic responses from the placebo effect. A second limitation is that hormesis merely further defines one response. Most toxicoses have many responses. The most complete information takes all responses and their connections into account.

Chamber for testing metered-dose propellant-driven aerosols of immunologically relevant proteins

A small aerosol chamber was developed for testing and delivery of aerosols of immunologically important proteins to the respiratory tracts of rodents. The chamber was designed to accommodate the small aerosol volumes produced by metered-dose propellant-driven aerosol canisters. Metered bursts of protein aerosols released into the chamber could be sampled for their particle sizes or used to expose the noses of up to six mice to the aerosols. The chamber consisted of a polyethylene tank with two removable plexiglass end plates. One end plate accommodated the propellant-driven, metered-dose, aerosol vial. The other end of the tank was fitted with a plate accepting aerosol sampling devices or a plate containing mouse restrainers. Uniform concentrations of aerosolized proteins were obtained at different positions in the chamber when sampled for particles of respirable size. Respirable-sized protein particles produced by propellant-driven aerosols ranged from 5 to 50% of total aerosolized protein. Propellant-driven aerosols of proteins released in the chamber produced aerosol particles equivalent to 15-26 micrograms of total protein exposure to the respiratory tract of each mouse. The chamber permitted aerosol releases without risk of operator exposure. This aerosol chamber will permit the testing of protein aerosols for their immunologic consequences to the respiratory tract. Potential proteins for testing in this device include immunizing vaccine antigens, immunomodulating cytokine proteins, and passive antibody aerosol therapies against respiratory infections.

Toxicity of nanomaterials

Abstract Nanotoxicology includes the study of adverse effects of nanomaterials on organisms and ecosystems. It is a challenging field because of the unique physical–chemical properties of materials at the nanoscale. At this scale the biological impacts of materials tend to be dependent on the unit size and shape of the material. Engineered nanomaterials are increasingly produced and utilized in a wide variety of products, and the uncertainties regarding their potential adverse health effects, which are associated with their unique properties, makes risk assessment challenging. Evidence of adverse health effects have been demonstrated in in vitro studies, in vivo studies, and in epidemiological studies. In many cases, however, the interpretation of available data is complicated by the use of very high doses to elicit cell responses and adverse effects; a lack of data relevant to chronic, low-dose exposures; complexities associated with nanomaterial characterization; and the dynamic nature of nanomaterials in the environment and in biological systems. The rate at which new nanomaterials with unique properties are developed is increasing and often outpaces the ability to characterize the potential adverse health risks associated with these materials. The growth of the nanomaterials and nanotechnology industries promises many benefits, which should be balanced by effective risk assessment. Emerging areas of nanotoxicological investigation include the interactions of nanomaterials with other toxicants, either by enhancing, or reducing adverse health risks as well as the potential adverse environmental effects associated with nanomaterials pollution.

Beyond Compliance and toward Sustainability: Advantages of Systems Environmental Engineering

New technologies are not only critical in supporting military and industrial success, but also play a significant role in advancing sustainable development. With the current global economic challenges, effective tools and partnerships which streamline the design and dissemination of these technologies are more important than ever. Accordingly, the systems environmental engineering approach utilized by the Urban Operations Laboratory (UOL), [comprised of M2 Technologies, Kansas State University, and CABEM Technologies], has facilitated innovative research, training, assessment, and product design for DoD and other stakeholders. Through strategic life-cycle environmental assessments (LCEA); programmatic environment, safety, and occupational health evaluations (PESHE); Health Hazard Assessments; and other proactive studies and reports, UOL has helped foster successful development and deployment of non-lethal technologies. More specifically, these efforts provide a framework for addressing complex environment, safety, and occupational health (ESOH) risks that affect personnel, infrastructure, property, and natural/cultural resources. Integrated analyses (comprehensive and transdisciplinary) involving flexible groups of subject matter experts, are employed in support of public and private collaborations with a focus on inputs, hazards, and constraints. This paper highlights the UOL process which can translate into advantages for a variety of projects (e.g., environmental, water, energy, infrastructure, etc.).