3,315 research outputs found
Vestibular selection criteria development
The experimental elicitation of motion sickness using a short arm centrifuge or a rotating chair surrounded by a striped cylindrical enclosure failed to reveal any systematic group or consistent individual relationship between changes in heart rate, blood pressure, and body temperature and the appearance of symptoms of motion sickness. A study of the influence of vision on susceptability to motion sickness during sudden stop simulation shows that having the eyes open during any part of the sudden stop assessment is more stressful than having them closed throughout the test. Subjects were found to be highly susceptible to motion sickness when tested in free fall and in high force phases of flight. The effect of touch and pressure cues on body orientation during rotation and in parabolic flight are considered as sensory as well as motor adaptation
Investigation of nickel hydrogen battery technology for the RADARSAT spacecraft
The low Earth orbit (LEO) operations of the RADARSAT spacecraft require high performance batteries to provide energy to the payload and platform during eclipse period. Nickel Hydrogen cells are currently competing with the more traditional Nickel Cadmium cells for high performance spacecraft applications at geostationary Earth orbit (GEO) and Leo. Nickel Hydrogen cells appear better suited for high power applications where high currents and high Depths of Discharge are required. Although a number of GEO missions have flown with Nickel Hydrogen batteries, it is not readily apparent that the LEO version of the Nickel Hydrogen cell is able to withstand the extended cycle lifetime (5 years) of the RADARSAT mission. The problems associated with Nickel Hydrogen cells are discussed in the contex of RADARSAT mission and a test program designed to characterize cell performance is presented
Impact of glucuronide interferences on therapeutic drug monitoring of posaconazole by tandem mass spectrometry
Background: Posaconazole is a novel antifungal drug for oral application intended especially for therapy of invasive mycoses. Due to variable gastrointestinal absorption, adverse side effects, and suspected drug-drug interactions, therapeutic drug monitoring (TDM) of posaconazole is recommended. Method: A fast ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for quantification of posaconazole with a run-time <3 min was developed and compared to a LC-MS/MS method and HPLC method with fluorescence detection. Results: During evaluation of UPLC-MS/MS, two earlier eluting peaks were observed in the MRM trace of posaconazole. This was only seen in patient samples, but not in spiked calibrator samples. Comparison with LC-MS/MS disclosed a significant bias with higher concentrations measured by LC-MS/MS, while UPLC-MS/MS showed excellent agreement with the commercially available HPLC method. In the LC-MS/MS procedure, comparably wide and left side shifted peaks were noticed. This could be ascribed to in-source fragmentation of conjugate metabolites during electrospray ionisation. Precursor and product ion scans confirmed the assumption that the additional compounds are posaconazole glucuronides. Reducing the cone voltage led to disappearance of the glucuronide peaks. Slight modification of the LC-MS/MS method enabled separation of the main interference, leading to significantly reduced deviation. Conclusions: These results highlight the necessity to reliably eliminate interference from labile drug metabolites for correct TDM results, either by sufficient separation or selective MS conditions. The presented UPLC-MS/MS method provides a reliable and fast assay for TDM of posaconazole. Clin Chem Lab Med 2010; 48:1723-31
Pair breaking by nonmagnetic impurities in the noncentrosymmetric superconductor CePt3Si
We have studied the effect of Ge substitution and pressure on the
heavy-fermion superconductor CePt3Si. Ge substitution on the Si site acts as
negative chemical pressure leading to an increase in the unit-cell volume but
also introduces chemical disorder. We carried out electrical resistivity and ac
heat-capacity experiments under hydrostatic pressure on CePt3Si1-xGex (x=0,
0.06). Our experiments show that the suppression of superconductivity in
CePt3Si1-xGex is mainly caused by the scattering potential, rather than volume
expansion, introduced by the Ge dopants. The antiferromagnetic order is
essentially not affected by the chemical disorder.Comment: 4 pages, 4 figure
Designing for Behavior and Culture in Local Food Systems
Although food systems and design may seem like they do not have much in common, design is as essential to the human experience as food. Herbert Simon is quoted as saying, Everyone designs who devises courses of action aimed at changing existing situations into preferred ones.
This view positions design to help address current issues around behavior and culture in local food systems. In this paper, we analyze the approaches of various common and emerging models in the local food movement through several design lenses. We highlight opportunities for innovation in local food initiatives by using design-based thinking tools that can influence behavior and culture around food. Finally, we present two case studies and provide actionable takeaways that can be used by local constituents. With a view toward fostering interdisciplinary dialogue around pressing food systems issues, the authors feel design is an important and accessible practice in the formulation of culture and behavior that can bring valuable insights to this discussion.https://scholarworks.uvm.edu/fss2014/1015/thumbnail.jp
Radiation Rates for Low Z Impurities in Edge Plasmas
The role of impurity radiation in the reduction of heat loads on divertor
plates in present experiments such as DIII-D, JET, JT-60, ASDEX, and Alcator
C-Mod, and in planned experiments such as ITER and TPX places a new degree of
importance on the accuracy of impurity radiation emission rates for electron
temperatures below 250 eV for ITER and below 150 eV for present experiments. We
have calculated the radiated power loss using a collisional radiative model for
Be, B, C, Ne and Ar using a multiple configuration interaction model which
includes density dependent effects, as well as a very detailed treatment of the
energy levels and meta-stable levels. The "collisional radiative" effects are
very important for Be at temperatures below 10 eV. The same effects are present
for higher Z impurities, but not as strongly. For some of the lower Z elements,
the new rates are about a factor of two lower than those from a widely used,
simpler average-ion package (ADPAK) developed for high Z ions and for higher
temperatures. Following the approach of Lengyel for the case where electron
heat conduction is the dominant mechanism for heat transport along field lines,
our analysis indicates that significant enhancements of the radiation losses
above collisional radiative model rates due to such effects as rapid recycling
and charge exchange recombination will be necessary for impurity radiation to
reduce the peak heat loads on divertor plates for high heat flux experiments
such as ITER.Comment: Preprint for the 11th PSI meeting, gzipped postscript with 11
figures, 14 page
Functional Characterisation of Alpha-Galactosidase A Mutations as a Basis for a New Classification System in Fabry Disease
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The study has been supported partially by an unrestricted scientific grant from Shire Human Genetic Therapies (Germany
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