89 research outputs found
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Tritium and noble-gas fission products in the nuclear fuel cycle. I. Reactors
Chemical Engineering Division waste management programs. Quarterly report, January--March 1975
Development work on the study of consolidation techniques for Zircaloy fuel-cladding hulls included scouting tests on volatility schemes for separating the zirconium as the volatile tetrachloride and ignition tests on several Zircaloy materials to further characterize the pyrophoric behavior of Zircaloy. All tests were with nonirradiated metal pending acquisition of irradiated samples. Installation is nearly complete of a glovebox facility for studies on the salvage of alpha-contaminated metals by pyrochemical methods. Disposal of a major portion of fission product tritium formed in light water reactor fuels by deep- well injection of the low-level aqueous waste from plants reprocessing such fuels is being evaluated. The question of siting is a very important factor in determining the feasibility of this particular disposal option. A review is given of the status of information for U. S. sedimentary basins, the areas most likely to be generally suitable for siting of waste wells. Work on the reliability of high-level-waste canisters included an examination of creep, shot- peening, and subcooling of the filler canister below storage temperatures, as methods of relieving stresses induced in canisters due to differential contraction of canister and glass during cooling. A method was investigated for relieving stresses in calcine-filled canisters. Properties of fission product oxides were examined to elucidate possible adverse corrosive effects at the canister-waste interface. (LK
PCR-DGGE assessment of the bacterial diversity of breast milk in women with lactational infectious mastitis
<p>Abstract</p> <p>Background</p> <p>Infectious mastitis is a common condition during lactation and in fact, represents one of the main causes leading to a precocious weaning. The number of studies dealing with lactational mastitis is low and, up to now, the etiological diagnosis is frequently made on the basis of unspecific clinical signs. The aim of this study was to investigate the microbial diversity of breast milk in 20 women with lactational mastitis employing culture-dependent and culture-independent (PCR-DGGE) approaches.</p> <p>Methods</p> <p>Breast milk samples were cultured in different media to investigate the presence of bacteria and/or yeasts, and a total of 149 representative isolates were identified to the species level by 16S rRNA gene PCR sequencing. The microorganisms recovered were compared with those found by PCR-DGGE analysis. To identify the DGGE profiles two reference markers of different microbial species were constructed. Sequence analysis of unknown bands was also performed.</p> <p>Results</p> <p>Staphylococci were the dominant bacterial group and <it>Staphylococcus epidermidis </it>was the dominant species. In a lower number of samples, other bacteria (mainly streptococci and a few gram-negative species) were also identified. Globally, PCR-DGGE results showed a good correlation with those obtained by culture-based methods. However, although DNA bands corresponding to different lactic acid bacteria were detected, such bacteria could not be isolated from the milk samples.</p> <p>Conclusion</p> <p>Staphylococci seem to be the main etiological agents of human lactational mastitis. The combined use of culture and molecular techniques allowed a better characterization of the bacterial diversity in milk from women suffering from infectious mastitis. Our results suggest that this condition could be the result of a disbiotic process where some of the bacterial species usually present in human milk outgrow (staphylococci) while others disappear (lactobacilli or lactococci).</p
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Argonne National Laboratory Reports
Report of the Argonne National Laboratory Chemical Engineering Division on fuel-cycle studies including pyro-chemical separation of plutonium and americium oxides from contaminated materials of construction such as steel, advanced solvent extraction techniques in the development of centrifugal contactors for use in Purex processes, and a review and evaluation of the encapsulation of high-level waste in a metal matrix
Complete Sequencing and Pan-Genomic Analysis of Lactobacillus delbrueckii subsp. bulgaricus Reveal Its Genetic Basis for Industrial Yogurt Production
Lactobacillus delbrueckii subsp. bulgaricus (Lb. bulgaricus) is an important species of Lactic Acid Bacteria (LAB) used for cheese and yogurt fermentation. The genome of Lb. bulgaricus 2038, an industrial strain mainly used for yogurt production, was completely sequenced and compared against the other two ATCC collection strains of the same subspecies. Specific physiological properties of strain 2038, such as lysine biosynthesis, formate production, aspartate-related carbon-skeleton intermediate metabolism, unique EPS synthesis and efficient DNA restriction/modification systems, are all different from those of the collection strains that might benefit the industrial production of yogurt. Other common features shared by Lb. bulgaricus strains, such as efficient protocooperation with Streptococcus thermophilus and lactate production as well as well-equipped stress tolerance mechanisms may account for it being selected originally for yogurt fermentation industry. Multiple lines of evidence suggested that Lb. bulgaricus 2038 was genetically closer to the common ancestor of the subspecies than the other two sequenced collection strains, probably due to a strict industrial maintenance process for strain 2038 that might have halted its genome decay and sustained a gene network suitable for large scale yogurt production
Evaluation of bacteriocinogenic activity, safety traits and biotechnological potential of fecal lactic acid bacteria (LAB), isolated from Griffon Vultures (Gyps fulvus subsp. fulvus)
The Earth: Plasma Sources, Losses, and Transport Processes
This paper reviews the state of knowledge concerning the source of magnetospheric plasma at Earth. Source of plasma, its acceleration and transport throughout the system, its consequences on system dynamics, and its loss are all discussed. Both observational and modeling advances since the last time this subject was covered in detail (Hultqvist et al., Magnetospheric Plasma Sources and Losses, 1999) are addressed
Geomagnetic disturbances may be environmental risk factor for multiple sclerosis: an ecological study of 111 locations in 24 countries
Observations of Closed Magnetic Flux Embedded in the Lobes During Periods of Northward IMF
The high latitude, lobe regions of the magnetosphere are often assumed to contain cool, low energy plasma populations. However, during periods of northward Interplanetary Magnetic Field, energetic plasma populations have occasionally been observed. We present three cases when Cluster observed uncharacteristically “hot” plasma populations in the lobe. For two of the three events, we present simultaneous observations of the plasma sheet observed by Double Star. The similarity between the plasma in the lobe and the plasma sheet suggests that the mechanism that produces plasma at high latitudes is likely to be tail reconnection, resulting in a trapped “wedge” of closed flux about the noon-midnight meridian. Complementary images from Imager for Magnetopause to Aurora Global Exploration and DMSP/Special Sensor Ultraviolet Spectrographic Imager show that transpolar arcs, which form in each event in at least one hemisphere, directly intersect the footprint of the Cluster spacecraft in all three events. The intersection of the Cluster footprint with the transpolar arcs is synchronous with the observation of the energetic plasma populations in the lobe. This further supports the conclusion that it is likely this energetic plasma observed in the high latitude lobe regions of magnetosphere is on closed field lines
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