Calculation of Precipitable Water for Stratospheric Observatory for Infrared Astronomy Aircraft (SOFIA): Airplane in the Night Sky

Stratospheric Observatory for Infrared Astronomy, or SOFIA, is the new generation airborne observatory station based at NASA s Dryden Aircraft Operations Facility, Palmdale, CA, to study the universe. Since the observatory detects infrared energy, water vapor is a concern in the atmosphere due to its known capacity to absorb infrared energy emitted by astronomical objects. Although SOFIA is hoping to fly above 99% of water vapor in the atmosphere it is still possible to affect astronomical observation. Water vapor is one of the toughest parameter to measure in the atmosphere, several atmosphere modeling are used to calculate water vapor loading. The water vapor loading, or Precipitable water, is being calculated by Matlab along the planned flight path. Over time, these results will help SOFIA to plan flights to regions of lower water vapor loading and hopefully improve the imagery collection of these astronomical features

Bioinspired silica as drug delivery systems and their biocompatibility

Silica nanoparticles have been shown to have great potential as drug delivery systems (DDS), however, their fabrication often involves harsh chemicals and energy intensive laborious methods. This work details the employment of a bioinspired "green" method for the controlled synthesis of silica, use of the products to entrap and release drug molecules and their cytotoxicity in order to develop novel DDS. Bioinspired silica synthesis occurs at pH 7, room temperature and in less than 5 minutes, resulting in a rapid, cheaper and greener route. Drugs were loaded into silica during the silica formation, thus allowing a one step and one pot method for simultaneous silica synthesis and drug loading. We established that the drug release profile can be modulated by synthetic parameters, which can allow design of tailored DDS. A systematic investigation using a two level factorial design was adopted in order to identify the key synthetic parameters and quantify their effects on silica formation, drug loading and drug release. The observation that these new DDS are considerably less cytotoxic than their current counterparts, and exhibit additional benefits such as green synthesis and ease of functionalization, strengthens the argument for their future use in DDS and other biomedical applications. © 2014 the Partner Organisations

The Secondary Photoelectron Effect: Gamma Ray Ionisation Enhancement in Tissues from High Atomic Number Elements

The absorption of gamma rays is roughly proportional to the fifth power of the atomic number of an element. This immediately raises the issue of tissue ionisation enhancement effects from photoelectron production by elements of high atomic number incorporated into living tissue. The issue was raised in the 1950s in relation to calcium in the bone but has received little attention since then. New results, derived from mathematical modelling carried out at the University of Ulster, of photoemission from nanoparticles of gold and uranium are presented. These show that significant ionisation enhancement effects can occur when incorporated particles of high atomic number are exposed to natural background gamma radiation, effects which increase sharply at the lower energy end of the spectrum, around 150 keV. The effects must also occur for molecular species. The general problem is discussed, with reference to the literature, and approximate enhancement factors are derived for the effect. The implications for the evolutionary selection of elements by life are explored

Error by design: Methods for predicting device usability

This paper introduces the idea of predicting ‘designer error’ by evaluating devices using Human Error Identification (HEI) techniques. This is demonstrated using Systematic Human Error Reduction and Prediction Approach (SHERPA) and Task Analysis For Error Identification (TAFEI) to evaluate a vending machine. Appraisal criteria which rely upon user opinion, face validity and utilisation are questioned. Instead a quantitative approach, based upon signal detection theory, is recommended. The performance of people using SHERPA and TAFEI are compared with heuristic judgement and each other. The results of these studies show that both SHERPA and TAFEI are better at predicting errors than the heuristic technique. The performance of SHERPA and TAFEI are comparable, giving some confidence in the use of these approaches. It is suggested that using HEI techniques as part of the design and evaluation process could help to make devices easier to use

Very Low Dose Fetal Exposure to Chernobyl Contamination Resulted in Increases in Infant Leukemia in Europe and Raises Questions about Current Radiation Risk Models

Following contamination from the Chernobyl accident in April 1986 excess infant leukemia (0–1 y) was reported from five different countries, Scotland, Greece, Germany, Belarus and Wales and Scotland combined. The cumulative absorbed doses to the fetus, as conventionally assessed, varied from 0.02 mSv in the UK through 0.06 mSv in Germany, 0.2 mSv in Greece and 2 mSv in Belarus, where it was highest. Nevertheless, the effect was real and given the specificity of the cohort raised questions about the safety of applying the current radiation risk model of the International Commission on Radiological Protection (ICRP) to these internal exposures, a matter which was discussed in 2000 by Busby and Cato [7,8] and also in the reports of the UK Committee examining Radiation Risk from Internal Emitters. Data on infant leukemia in the United Kingdom, chosen on the basis of the cohorts defined by the study of Greece were supplied by the UK Childhood Cancer Research Group. This has enabled a study of leukemia in the combined infant population of 15,466,845 born in the UK, Greece, and Germany between 1980 and 1990. Results show a statistically significant excess risk RR = 1.43 (95% CI 1.13 < RR < 1.80 (2-tailed); p = 0.0025) in those born during the defined peak exposure period of 01/07/86 to 31/12/87 compared with those born between 01/01/80 and 31/12/85 and 01/01/88 and 31/12/90. The excess risks in individual countries do not increase monotonically with the conventionally calculated doses, the relation being biphasic, increasing sharply at low doses and falling at high doses. This result is discussed in relation to fetal/cell death at higher doses and also to induction of DNA repair. Since the cohort is chosen specifically on the basis of exposure to internal radionuclides, the result can be expressed as evidence for a significant error in the conventional modeling for such internal fetal exposures

Critical perspectives on ‘consumer involvement’ in health research: epistemological dissonance and the know-do gap

Researchers in the area of health and social care (both in Australia and internationally) are encouraged to involve consumers throughout the research process, often on ethical, political and methodological grounds, or simply as ‘good practice’. This paper presents findings from a qualitative study in the UK of researchers’ experiences and views of consumer involvement in health research. Two main themes are presented in the paper. Firstly, we explore the ‘know-do gap’ which relates to the tensions between researchers’ perceptions of the potential benefits of, and their actual practices in relation to, consumer involvement. Secondly, we focus on one of the reasons for this ‘know-do gap’, namely epistemological dissonance. Findings are linked to issues around consumerism in research, lay/professional knowledges, the (re)production of professional and consumer identities and the maintenance of boundaries between consumers and researchers

Searching for a Stochastic Background of Gravitational Waves with LIGO

The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is $\Omega_{\rm GW} < 6.5 \times 10^{-5}$. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

Search for gravitational wave bursts in LIGO's third science run

We report on a search for gravitational wave bursts in data from the three LIGO interferometric detectors during their third science run. The search targets subsecond bursts in the frequency range 100-1100 Hz for which no waveform model is assumed, and has a sensitivity in terms of the root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published in Classical and Quantum Gravit