The current interest in returning human exploration to the Moon and Mars makes cost-effective and low-mass health monitoring sensors essential for spacecraft development. In space, there are many ...surface measurements that are required to monitor the condition of the spacecraft including: surface temperature, radiation dose, and impact. Through the use of tailored phosphors, these conditions can be monitored. Practical space-based phosphor sensors will depend heavily upon research investigating the resistance of phosphors to ionizing radiation and their ability to anneal or 'self-heal' from damage caused by ionizing radiation. For the present research, a group of lutetium orthophosphate (LuPO{sub 4}) crystals with dopants including europium, erbium, and neodymium were characterized. Cathodoluminescence (CL) testing was performed using the low energy electron system located at the NASA Marshall Space Flight Center in Huntsville, Alabama. The data were collected using an Ocean Optics HR4000 spectrometer and a fiber optic feed-through. Previous research has shown that increases in both beam energy and current density improved the CL fluorescence yield. While the total electron dose was small, the intention was to maximize the number of irradiated materials. Additionally, these samples were evaluated using a PTI Quantum Master Spectrophotometer to determine the photoluminescence emission spectra.
Perfluoroalkyl substances were determined in polar bears (Ursus maritimus) collected in East Greenland (69 degrees 00'N to 74 degrees 00"N) to compare with other populations and to examine effects of ...age and gender on concentrations of these contaminants. Hepatic tissue (n = 29) was analyzed for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate, heptadecafluorooctane sulfonamide (PFOSA), and perfluoroalkyl carboxylates (PFCAs) with C9-C15 perfluorinated carbon chains by liquid chromatography tandem mass spectrometry. Concentrations of PFOS found in samples from East Greenland (mean = 2,470+/-1,320 ng/g wet weight) were similar to Hudson Bay, Canada, and both populations had significantly greater concentrations than those reported for Alaska, suggesting a spatial trend. Male bears showed a significant increase in concentration up to age six for PFCAs with C10-C14 carbon chains (r2 > or = 0.50, p < or = 0.05). Significant correlations were found between adjacent chain length PFCAs, (e.g., PFNA to PFDA: p < 0.05; r2 = 0.90). This may indicate a common source for these chemicals, although the specifics of source and mode of transport are unknown. No significant correlations were found between concentrations of PFCAs in liver tissue and previously reported polychlorinated biphenyl (PCB) congeners analyzed in fat samples from the same bears.
The disposition of 5-4-14Cazacytidine, administered i.v. as a bolus or continuous infusion, was studied in cancer patients. After bolus, plasma 14C levels exhibited as multiphasic disappearance ...pattern; half-life (t1/2, beta phase) = 3.4 to 6.2 hr. Of 14C in plasma, less than 2% was associated with 5-4-14Cazacytidine 30 min after dose. The ratios of 14C levels were: red cells/plasma, approximately 0.8; leukocytes/plasma, 1.1 to 2.3; nucleic acids/leukocytes, 0.2 to 0.43; sputum/plasma, 0.05 to 0.17. Urinary excretion (3 days) accounted for 73 to 98% of 14C, LEss than 1% in feces. The relative concentration of 5-azacytidine in plasma with continuous infusion stayed higher than with bolus; urinary excretion was similar. Fewer side effects were observed with continuous infusion than with bolus. The stability of 5-azacytidine was determined in various media at several temperatures by thin layer chromatography and nuclear magnetic resonance. At 20 degrees in Ringer's lactate (pH 6.2), the t1/2 was 94 to 100 hr. Stability increased with lowering of temperature and pH. From our data we conclude that 5-azacytidine should be given by continuous infusion rather than as a bolus.
Global warming is expected to change fire regimes, likely increasing the severity and extent of wildfires in many ecosystems around the world. What will be the landscape-scale effects of these ...altered fire regimes? Within what theoretical contexts can we accurately assess these effects? We explore the possible effects of altered fire regimes on landscape patch dynamics, dominant species (tree, shrub, or herbaceous) and succession, sensitive and invasive plant and animal species and communities, and ecosystem function. Ultimately, we must consider the human dimension: what are the policy and management implications of increased fire disturbance, and what are the implications for human communities?
Perfluoroalkyl substances were determined in polar bears (Ursus maritimus) collected in East Greenland (69°00′N to 74°00′'N) to compare with other populations and to examine effects of age and gender ...on concentrations of these contaminants. Hepatic tissue (n = 29) was analyzed for perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate, heptadecafluorooctane sulfonamide (PFOSA), and perfluoroalkyl carboxylates (PFCAs) with C9–C15 perfluorinated carbon chains by liquid chromatography tandem mass spectrometry. Concentrations of PFOS found in samples from East Greenland (mean = 2,470 ± 1,320 ng/g wet weight) were similar to Hudson Bay, Canada, and both populations had significantly greater concentrations than those reported for Alaska, suggesting a spatial trend. Male bears showed a significant increase in concentration up to age six for PFCAs with C10–C14 carbon chains (r2 ≥ 0.50, p ≤ 0.05). Significant correlations were found between adjacent chain length PFCAs, (e.g., PFNA to PFDA: p < 0.05; r2 = 0.90). This may indicate a common source for these chemicals, although the specifics of source and mode of transport are unknown. No significant correlations were found between concentrations of PFCAs in liver tissue and previously reported polychlorinated biphenyl (PCB) congeners analyzed in fat samples from the same bears.
High-dose intravenous gammaglobulin (IVIgG) was given to 12 children and adults with chronic idiopathic thrombocytopenic purpura (ITP) to avoid splenectomy or because they either failed to respond to ...or required maintenance with high doses of steroids and/or immunosuppressives. The average platelet count increase to initial therapy was 239,500/μ1 (range 23,000–790,000). A concomitant IgG Fc receptor blockade, measured by IgG-sensitized 51Cr-labeled autologous erythrocytes, was seen in 11 of 11 patients tested, both splenectomized and not splenecto-mized, lasting 3–4 wk. Six or more months after treatment, 2 children are in remission, 2 children and 2 adults are stable requiring no therapy with platelet counts of approximately 50,000 and 30,000, respectively, 3 children require maintenance IVIgG therapy at 2–10-wk intervals, and 1 child and 2 adults have become refractory to further IVIgG. Splenectomy was not performed in 4 children. Two adults were able to discontinue daily prednisone. The 3 patients who became unresponsive to Swiss Red Cross gammaglobulin (IgSRK) therapy did so in conjunction with a markedly elevated platelet-associated IgG and IgM. Serum IgM increased an average of 103 mg/dl after the IVIgG infusions. No significant side effects were seen.
Quantitative determination of the elemental composition of metals and other solids by glow discharge mass spectrometry requires a calibration factor for each element. In past work, these factors, ...called relative ion yields (RIYs), have been determined experimentally from the mass spectra of standards of certified composition. The RIYs of some elements were found to be over 10 times larger than the RIYs of other elements. In this study a simple calculation of the RIYs of the elements within the same sample is derived from a theoretical framework which takes into account the combined effects of sputtering and ionization. The ionization function involves the electron affinity and the first ionization potential of each element, plus two unknown parameters. By favorable selection of a temperature parameter and a chemical-potential parameter, the RIYs calculated by this method were found to agree satisfactority with the experimental RIYs of former work. The temperature of 16,000 K (used in this work) corresponds to an average electron energy of ∼ 2 eV.
To determine risk factors for Mycobacterium xenopi isolation in patients following a pseudo-outbreak of infection with the organism.
Retrospective cohort analysis of mycobacteriology laboratory ...specimen records and frequency-matched case-control study of hospital patients.
General community hospital.
For the case-control study, 13 case patients and 39 randomly selected controls with mycobacterial cultures negative for M xenopi, frequency matched by specimen source, whose specimens were submitted from June 1990 through June 1991.
Between June 1990 and June 1991, M xenopi was isolated from 13 clinical specimens processed at a midwestern hospital, including sputum (n = 6), bronchial washings (2), urine (4), and stool (1). None of the patients with M xenopi-positive specimens had apparent mycobacterial disease, although five received antituberculosis drug therapy for a range of one to six months. Specimens collected in a nonsterile manner were more likely to grow the organism than those collected aseptically (3.1% versus 0, relative risk = infinity, P = 0.003). M xenopi isolation was attributed to exposure of clinical specimens to tap water, including rinsing of bronchoscopes with tap water after disinfection, irrigation with tap water during colonoscopy, gargling with tap water before sputum collection, and collecting urine in recently rinsed bedpans. M xenopi was isolated from tap water in 20 of 24 patient rooms tested, the endoscopy suite, and the central hot water mixing tank, but not from water in the microbiology laboratory. The pseudo-outbreak occurred following a decrease in the hot water temperature from 130 degrees F to 120 degrees F in 1989.
Maintenance of a higher water temperature and improved specimen collection protocols and instrument disinfection procedures probably would have prevented this pseudo-outbreak.
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