David J. Loftus

Toxicity of lunar dust

The formation, composition and physical properties of lunar dust are incompletely characterised with regard to human health. While the physical and chemical determinants of dust toxicity for materials such as asbestos, quartz, volcanic ashes and urban particulate matter have been the focus of substantial research efforts, lunar dust properties, and therefore lunar dust toxicity may differ substantially. In this contribution, past and ongoing work on dust toxicity is reviewed, and major knowledge gaps that prevent an accurate assessment of lunar dust toxicity are identified. Finally, a range of studies using ground-based, low-gravity, and in situ measurements is recommended to address the identified knowledge gaps. Because none of the curated lunar samples exist in a pristine state that preserves the surface reactive chemical aspects thought to be present on the lunar surface, studies using this material carry with them considerable uncertainty in terms of fidelity. As a consequence, in situ data on lunar dust properties will be required to provide ground truth for ground-based studies quantifying the toxicity of dust exposure and the associated health risks during future manned lunar missions.

NASA Radiation Biomarker WorkshopSeptember 27–28, 2007

Abstract Straume, T., Amundson, S. A., Blakely, W. F., Burns, F. J., Chen, A., Dainiak, N., Franklin, S., Leary, J. A., Loftus, D. J., Morgan, W. F., Pellmar, T. C., Stolc, V., Turteltaub, K. W., Vaughan, A. T., Vijayakumar, S. and Wyrobek, A. J. NASA Radiation Biomarker Workshop. September 27–28, 2007. Radiat. Res. 170, 393–405 (2008). A summary is provided of presentations and discussions at the NASA Radiation Biomarker Workshop held September 27–28, 2007 at NASA Ames Research Center in Mountain View, CA. Invited speakers were distinguished scientists representing key sectors of the radiation research community. Speakers addressed recent developments in the biomarker and biotechnology fields that may provide new opportunities for health-related assessment of radiation-exposed individuals, including those exposed during long-duration space travel. Topics discussed included the space radiation environment, biomarkers of radiation sensitivity and individual susceptibility, molecular signatures of low-dose responses, multivariate analysis of gene expression, biomarkers in biodefense, biomarkers in radiation oncology, biomarkers and triage after large-scale radiological incidents, integrated and multiple biomarker approaches, advances in whole-genome tiling arrays, advances in mass spectrometry proteomics, radiation biodosimetry for estimation of cancer risk in a rat skin model, and confounding factors. A summary of conclusions is provided at the end of the report.

Morphological and chemical changes of aerosolized E. coli treated with a dielectric barrier discharge

This study presents the morphological and chemical modification of the cell structure of aerosolized Escherichia coli treated with a dielectric barrier discharge (DBD). Exposure to DBD results in severe oxidation of the bacteria, leading to the formation of hydroxyl groups and carbonyl groups and a significant reduction in amine functionalities and phosphate groups. Near edge x-ray absorption fine structure (NEXAFS) measurements confirm the presence of additional oxide bonds upon DBD treatment, suggesting oxidation of the outer layer of the cell wall. Electron microscopy images show that the bacteria undergo physical distortion to varying degrees, resulting in deformation of the bacterial structure. The electromagnetic field around the DBD coil causes severe damage to the cell structure, possibly resulting in leakage of vital cellular materials. The oxidation and chemical modification of the bacterial components are evident from the Fourier transform infrared spectroscopy and NEXAFS results. The bacterial reculture experiments confirm inactivation of airborne E. coli upon treating with DBD.

Biomarker-Detection Technologies for Comprehensive Medical Diagnosis During Deep-Space Missions

Abstract: Human deep-space missions to Mars and beyond will require development of a compact device that can provide comprehensive in-flight medical diagnostic capability to support the health of astronauts. Key features should include the ability to handle multiple sample types (blood, saliva, breath), and the ability to measure virtually any biomarker, including future biomarkers that may emerge. Here we identify compatible technologies and their associated patents that can be integrated to create such a device, to provide essential hematology information (blood cell counts, white cell differential) and to detect proteins and other biomolecules needed to assess spaceflight medical conditions. The ability to analyze breath and saliva specimens is a priority. These specimens are fully non-invasive hence no risk is associated with sampling and can provide rapid health assessment information that could be critical for urgent medical issues that may arise during EVA, prior to removal of the spacesuit. In addition to space applications, the device we envision would have applications for health care on Earth, in the military, in developing countries, and other settings with limited access to conventional medical resources.

Meeting Report--NASA Radiation Biomarker Workshop

A summary is provided of presentations and discussions from the NASA Radiation Biomarker Workshop held September 27-28, 2007, at NASA Ames Research Center in Mountain View, California. Invited speakers were distinguished scientists representing key sectors of the radiation research community. Speakers addressed recent developments in the biomarker and biotechnology fields that may provide new opportunities for health-related assessment of radiation-exposed individuals, including for long-duration space travel. Topics discussed include the space radiation environment, biomarkers of radiation sensitivity and individual susceptibility, molecular signatures of low-dose responses, multivariate analysis of gene expression, biomarkers in biodefense, biomarkers in radiation oncology, biomarkers and triage following large-scale radiological incidents, integrated and multiple biomarker approaches, advances in whole-genome tiling arrays, advances in mass-spectrometry proteomics, radiation biodosimetry for estimation of cancer risk in a rat skin model, and confounding factors. Summary conclusions are provided at the end of the report.

Creation of Statistically Equivalent Periodic Unit Cells for Protein-Bound Soils

In 2010, NASA was directed to develop technologies to reduce the cost and risk of space exploration and send humans beyond the International Space Station. A central challenge to long-duration space missions is a lack of available construction materials in situ. This work focuses on a novel class of composites that can be produced extraterrestrially in situ by desiccating a mixture of soil, water, and protein binder to create a strong, versatile material. To date, experimental tests of mechanical properties have shown significant variability among samples.This paper focuses on the creation of Statistically Equivalent Periodic Unit Cells (SEPUC) to stochastically model protein-bound composites for the purpose of creating FE models that provide insights into experimental results. Model inputs include the soil granulometry and volume fractions of the phases. Ellipsoidal particles are placed, and protein coatings and bridges are created, using a Level Set based Random Sequential Addition algorithm. Each image is assigned a statistical descriptor and a simple genetic algorithm is used to optimize for a statistical descriptor close to that of experimental specimens.The framework is validated by comparing experimental images of protein-bound soils obtained by micro-CT scanning with those obtained through the SEPUC framework.Copyright