1,009 research outputs found
NASA Light-Emitting Diodes for the Prevention of Oral Mucositis in Pediatric Bone Marrow Transplant Patients
Objective: The purpose of this study was to determine the effects of prophylactic near-infrared light therapy from light-emitting diodes (LEDs) in pediatric bone marrow transplant (BMT) recipients.
Background Data: Oral mucositis (OM) is a frequent side effect of chemotherapy that leads to increased morbidity. Near-infrared light has been shown to produce biostimulatory effects in tissues, and previous results using nearinfrared lasers have shown improvement in OM indices. However, LEDs may hold greater potential for clinical applications.
Materials and Methods: We recruited 32 consecutive pediatric patients undergoing myeloablative therapy in preparation for BMT. Patients were examined by two of three pediatric dentists trained in assessing the Schubert oral mucositis index (OMI) for left and right buccal and lateral tongue mucosal surfaces, while the patients were asked to rate their current left and right mouth pain, left and right xerostomia, and throat pain. LED therapy consisted of daily treatment at a fluence of 4 J/cm2 using a 670-nm LED array held to the left extraoral epithelium starting on the day of transplant, with a concurrent sham treatment on the right. Patients were assessed before BMT and every 2–3 days through posttransplant day 14. Outcomes included the percentage of patients with ulcerative oral mucositis (UOM) compared to historical epidemiological controls, the comparison of left and right buccal pain to throat pain, and the comparison between sides of the buccal and lateral tongue OMI and buccal pain.
Results: The incidence of UOM was 53%, compared to an expected rate of 70–90%. There was also a 48% and 39% reduction of treated left and right buccal pain, respectively, compared to untreated throat pain at about posttransplant day 7 (p \u3c 0.05). There were no significant differences between sides in OMI or pain.
Conclusion: Although more studies are needed, LED therapy appears useful in the prevention of OM in pediatric BMT patients
Prospects of cold dark matter searches with an ultra-low-energy germanium detector
The report describes the research program on the development of
ultra-low-energy germanium detectors, with emphasis on WIMP dark matter
searches. A threshold of 100 eV is achieved with a 20 g detector array,
providing a unique probe to the low-mas WIMP. Present data at a surface
laboratory is expected to give rise to comparable sensitivities with the
existing limits at the WIMP-mass range. The projected
parameter space to be probed with a full-scale, kilogram mass-range experiment
is presented. Such a detector would also allow the studies of neutrino-nucleus
coherent scattering and neutrino magnetic moments.Comment: 3 pages, 4 figures, Proceedings of TAUP-2007 Conferenc
Prospects For Identifying Dark Matter With CoGeNT
It has previously been shown that the excess of events reported by the CoGeNT
collaboration could be generated by elastically scattering dark matter
particles with a mass of approximately 5-15 GeV. This mass range is very
similar to that required to generate the annual modulation observed by
DAMA/LIBRA and the gamma rays from the region surrounding the Galactic Center
identified within the data of the Fermi Gamma Ray Space Telescope. To
confidently conclude that CoGeNT's excess is the result of dark matter,
however, further data will likely be needed. In this paper, we make projections
for the first full year of CoGeNT data, and for its planned upgrade. Not only
will this body of data more accurately constrain the spectrum of nuclear recoil
events, and corresponding dark matter parameter space, but will also make it
possible to identify seasonal variations in the rate. In particular, if the
CoGeNT excess is the product of dark matter, then one year of CoGeNT data will
likely reveal an annual modulation with a significance of 2-3. The
planned CoGeNT upgrade will not only detect such an annual modulation with high
significance, but will be capable of measuring the energy spectrum of the
modulation amplitude. These measurements will be essential to irrefutably
confirming a dark matter origin of these events.Comment: 6 pages, 6 figure
Using 67Cu to Study the Biogeochemical Cycling of Copper in the Northeast Subarctic Pacific Ocean
Microbial copper (Cu) nutrition and dissolved Cu speciation were surveyed along Line P, a coastal to open ocean transect that extends from the coast of British Columbia, Canada, to the high-nutrient-low-chlorophyll (HNLC) zone of the northeast subarctic Pacific Ocean. Steady-state size fractionated Cu uptake rates and Cu:C assimilation ratios were determined at in situ Cu concentrations and speciation using a 67Cu tracer method. The cellular Cu:C ratios that we measured (~30 µmol Cu mol C-1) are similar to recent estimates using synchrotron x-ray fluorescence (SXRF), suggesting that the 67Cu method can determine in situ metabolic Cu demands. We examined how environmental changes along the Line P transect influenced Cu metabolism in the sub-microplankton community. Cellular Cu:C assimilation ratios and uptake rates were compared with net primary productivity, bacterial abundance and productivity, total dissolved Cu, Cu speciation, and a suite of other chemical and biological parameters. Total dissolved Cu concentrations ([Cu]d) were within a narrow range (1.46 to 2.79 nM), and Cu was bound to a ~5-fold excess of strong ligands with conditional stability constants ( ) of ~1014. Free Cu2+ concentrations were low (pCu 14.4 to 15.1), and total and size fractionated net primary productivity (NPPV; µg C L-1 d-1) were negatively correlated with inorganic Cu concentrations ([Cu′]). We suggest this is due to greater Cu′ drawdown by faster growing phytoplankton populations. Using the relationship between [Cu′] drawdown and NPPV, we calculated a regional photosynthetic Cu:C drawdown export ratio between 1.5 and 15 µmol Cu mol C-1, and a mixed layer residence time (2.5 to 8 years) that is similar to other independent estimates (2-12 years). Total particulate Cu uptake rates were between 22 and 125 times faster than estimates of Cu export; this is possibly mediated by rapid cellular Cu uptake and efflux by phytoplankton and bacteria or the effects of grazers and bacterial remineralization on dissolved Cu. These results provide a more detailed understanding of the interactions between Cu speciation and microorganisms in seawater, and present evidence that marine phytoplankton modify Cu speciation in the open ocean
The inverse hazard law: Blood pressure, sexual harassment, racial discrimination, workplace abuse and occupational exposures in US low-income black, white and Latino workers
http://dx.doi.org/10.1016/j.socscimed.2008.09.03
Experimental constraints on a dark matter origin for the DAMA annual modulation effect
A claim for evidence of dark matter interactions in the DAMA experiment has
been recently reinforced. We employ a new type of germanium detector to
conclusively rule out a standard isothermal galactic halo of Weakly Interacting
Massive Particles (WIMPs) as the explanation for the annual modulation effect
leading to the claim. Bounds are similarly imposed on a suggestion that dark
pseudoscalars mightlead to the effect. We describe the sensitivity to light
dark matter particles achievable with our device, in particular to
Next-to-Minimal Supersymmetric Model candidates.Comment: v4: introduces recent results from arXiv:0807.3279 and
arXiv:0807.2926. Sensitivity to pseudoscalars is revised in light of the
first. Discussion on the subject adde
Detrital-Zircon Geochronology of the Metasedimentary Rocks of North-Western Graham Land
Metasedimentary rocks constitute an important but comparatively poorly understood part of the Antarctic Peninsula. Herein we report single-grain U-Pb detrital-zircon ages from samples of the Trinity Peninsula and Botany Bay Groups of north-western Graham Land. All studied samples are dominated by a large and narrowly defined population of late Palaeozoic zircons. Significant early–middle Palaeozoic and minor Neoproterozoic and Mesoproterozoic sub-populations constitute the majority of pre-Carboniferous grains. These detrital-zircon age populations are consistent with sediment derivation entirely from western Gondwana sources. Despite the clear Gondwana signatures, our data suggest that the Trinity Peninsula Group province was either a parautochthonous peri-Gondwanan terrane later accreted to the Antarctic Peninsula, or a significant topographic barrier precluded voluminous sediment contributions from the interior of Gondwana. Statistical comparisons with similar metasedimentary complexes of southern South America, the South Shetland Islands and eastern New Zealand indicate a diversity of sediment provenance not previously recognized, but may provide a means to better determine the pre-break-up configuration of western Gondwana. Although insufficient to definitively restore Antarctic Peninsula components adjacent to South American complexes, some Trinity Peninsula Group samples exhibit robust affinities to the Miers Bluff Formation in the South Shetland Islands and the Duque de York and Main Range Metamorphic Complexes of the Patagonian Andes
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