High Purity Americium-241 for Fuel Cycle R&D Program

Previously the U.S. Department of Energy released Am-241 for various applications such as smoke detectors and Am-Be neutron sources for oil wells. At this date there is a shortage of usable, higher purity Am-241 in metal and oxide form available in the United States. Recently, the limited source of Am-241 has been from Russia with production being contracted to existing customers. The shortage has resulted in the price per gram rising dramatically over the last few years. DOE-NE currently has need for high purity Am-241 metal and oxide to fabricate fuel pellets for reactor testing in the Fuel Cycle R&D program. All the available high purity americium has been gathered from within the DOE system of laboratories. However, this is only a fraction of the projected needs of FCRD over the next 10 years. Therefore, FCR&D has proposed extraction and purification concepts to extract Am-241 from a mixed AmO2-PuO2 feedstock stored at the Savannah River Site. The most simple extraction system is based upon high temperature reduction using lanthanum metal with concurrent evaporation and condensation to produce high purity Am metal. Metallic americium has over a four order of magnitude higher vapor pressure than plutonium. Results from small-scale reduction experiments are presented. These results confirm thermodynamic predictions that at 1000 deg C metallic lanthanum reduces both PuO2 and AmO2. Faster kinetics are expected for temperatures up to about 1500 deg C

Oxidation Protection of Uranium Nitride Fuel using Liquid Phase Sintering

Two methods are proposed to increase the oxidation resistance of uranium nitride (UN) nuclear fuel. These paths are: (1) Addition of USi{sub x} (e.g. U3Si2) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with various compounds (followed by densification via Spark Plasma Sintering or Liquid Phase Sintering) that will greatly increase oxidation resistance. The advantages (high thermal conductivity, very high melting point, and high density) of nitride fuel have long been recognized. The sodium cooled BR-10 reactor in Russia operated for 18 years on uranium nitride fuel (UN was used as the driver fuel for two core loads). However, the potential advantages (large power up-grade, increased cycle lengths, possible high burn-ups) as a Light Water Reactor (LWR) fuel are offset by uranium nitride's extremely low oxidation resistance (UN powders oxidize in air and UN pellets decompose in hot water). Innovative research is proposed to solve this problem and thereby provide an accident tolerant LWR fuel that would resist water leaks and high temperature steam oxidation/spalling during an accident. It is proposed that we investigate two methods to increase the oxidation resistance of UN: (1) Addition of USi{sub x} (e.g. U{sub 3}Si{sub 2}) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with compounds (followed by densification via Spark Plasma Sintering) that will greatly increase oxidation resistance

Fabrication of Dual Phase Magnesia-Zirconia Ceramics Doped with Plutonia and Erbia

Dual phase magnesia-zirconia ceramics doped with plutonia and erbia are being evaluated as an inert matrix fuel (IMF) for light water reactors (LWR). The motivation for this work is to develop an IMF with a thermal conductivity superior to that of the fuels based on single-phase yttria stabilized zirconia. The innovative fuel developed at INL is comprised of two major phases: pure MgO and quaternary solid solution consisting of MgO, ZrO{sub 2}, Er{sub 2}O{sub 3} and PuO{sub 2}. Pure MgO phase acts as an efficient heat conductor. It has been shown [1] that dual phase MgO-ZrO{sub 2} ceramics have the thermal conductivity superior to that of UO{sub 2} and have notable chemical resistance to water at the temperature of 573 K and pressure 8.6 MPa, which makes them attractive for use as an IMF matrix in LWRs

Transmission of Staphylococcus aureus between health-care workers, the environment, and patients in an intensive care unit: a longitudinal cohort study based on whole-genome sequencing

Background: Health-care workers have been implicated in nosocomial outbreaks of Staphylococcus aureus, but the dearth of evidence from non-outbreak situations means that routine health-care worker screening and S aureus eradication are controversial. We aimed to determine how often S aureus is transmitted from health-care workers or the environment to patients in an intensive care unit (ICU) and a high-dependency unit (HDU) where standard infection control measures were in place. Methods: In this longitudinal cohort study, we systematically sampled health-care workers, the environment, and patients over 14 months at the ICU and HDU of the Royal Sussex County Hospital, Brighton, England. Nasal swabs were taken from health-care workers every 4 weeks, bed spaces were sampled monthly, and screening swabs were obtained from patients at admission to the ICU or HDU, weekly thereafter, and at discharge. Isolates were cultured and their whole genome sequenced, and we used the threshold of 40 single-nucleotide variants (SNVs) or fewer to define subtypes and infer recent transmission. Findings: Between Oct 31, 2011, and Dec 23, 2012, we sampled 198 health-care workers, 40 environmental locations, and 1854 patients; 1819 isolates were sequenced. Median nasal carriage rate of S aureus in health-care workers at 4-weekly timepoints was 36·9% (IQR 35·7–37·3), and 115 (58%) health-care workers had S aureus detected at least once during the study. S aureus was identified in 8–50% of environmental samples. 605 genetically distinct subtypes were identified (median SNV difference 273, IQR 162–399) at a rate of 38 (IQR 34–42) per 4-weekly cycle. Only 25 instances of transmission to patients (seven from health-care workers, two from the environment, and 16 from other patients) were detected. Interpretation: In the presence of standard infection control measures, health-care workers were infrequently sources of transmission to patients. S aureus epidemiology in the ICU and HDU is characterised by continuous ingress of distinct subtypes rather than transmission of genetically related strains. Funding: UK Medical Research Council, Wellcome Trust, Biotechnology and Biological Sciences Research Council, UK National Institute for Health Research, and Public Health England

On the notion of home and the goals of palliative care

The notion of home is well known from our everyday experience, and plays a crucial role in all kinds of narratives about human life, but is hardly ever systematically dealt with in the philosophy of medicine and health care. This paper is based upon the intuitively positive connotation of the term “home.” By metaphorically describing the goal of palliative care as “the patient’s coming home,” it wants to contribute to a medical humanities approach of medicine. It is argued that this metaphor can enrich our understanding of the goals of palliative care and its proper objectives. Four interpretations of “home” and “coming home” are explored: (1) one’s own house or homelike environment, (2) one’s own body, (3) the psychosocial environment, and (4) the spiritual dimension, in particular, the origin of human existence. Thinking in terms of coming home implies a normative point of view. It represents central human values and refers not only to the medical-technical and care aspects of health care, but also to the moral context

Awards, Archives, and Affects: Tropes in the World Press Photo Contest 2009 - 2011

__Abstract__ Photography contests have assumed an increasingly significant public role in the context of the global surge of mass-mediated war reporting. This study focuses on the recurrence of visual tropes in press photographs awarded in the annual contest World Press Photo (WPP) in the years 2009–11. By tropes, we mean conventions (e.g. a mourning woman, a civilian facing soldiers, a distressed witness to an atrocity) that remain unchanged despite their travels across the visual sphere, gaining professional and public recognition and having a strong affective impact. We contend that photography contests such as the WPP influence and organize a process of generic understanding of war, disaster and atrocity that is based on a number of persistent tropes, such as the mourner, the protester or the survivor amidst chaos and ruins. We further show that these tropes are gendered along traditional conceptions of femininity and masculinity, appealing strongly to both judges and wider audiences. The evidence for our claim comes from an analysis of the photographs that won awards, observation of the judging sessions, semi-structured interviews with three jury chairmen, and public commentary on the juries’ choices (blogs, newspapers and websites)

Production of Extracellular Traps against Aspergillus fumigatus In Vitro and in Infected Lung Tissue Is Dependent on Invading Neutrophils and Influenced by Hydrophobin RodA

Aspergillus fumigatus is the most important airborne fungal pathogen causing life-threatening infections in immunocompromised patients. Macrophages and neutrophils are known to kill conidia, whereas hyphae are killed mainly by neutrophils. Since hyphae are too large to be engulfed, neutrophils possess an array of extracellular killing mechanisms including the formation of neutrophil extracellular traps (NETs) consisting of nuclear DNA decorated with fungicidal proteins. However, until now NET formation in response to A. fumigatus has only been demonstrated in vitro, the importance of neutrophils for their production in vivo is unclear and the molecular mechanisms of the fungus to defend against NET formation are unknown. Here, we show that human neutrophils produce NETs in vitro when encountering A. fumigatus. In time-lapse movies NET production was a highly dynamic process which, however, was only exhibited by a sub-population of cells. NETosis was maximal against hyphae, but reduced against resting and swollen conidia. In a newly developed mouse model we could then demonstrate the existence and measure the kinetics of NET formation in vivo by 2-photon microscopy of Aspergillus-infected lungs. We also observed the enormous dynamics of neutrophils within the lung and their ability to interact with and phagocytose fungal elements in situ. Furthermore, systemic neutrophil depletion in mice almost completely inhibited NET formation in lungs, thus directly linking the immigration of neutrophils with NET formation in vivo. By using fungal mutants and purified proteins we demonstrate that hydrophobin RodA, a surface protein making conidia immunologically inert, led to reduced NET formation of neutrophils encountering Aspergillus fungal elements. NET-dependent killing of Aspergillus-hyphae could be demonstrated at later time-points, but was only moderate. Thus, these data establish that NET formation occurs in vivo during host defence against A. fumigatus, but suggest that it does not play a major role in killing this fungus. Instead, NETs may have a fungistatic effect and may prevent further spreading

Oxidation Protection of Uranium Nitride Fuel using Liquid Phase Sintering

Two methods are proposed to increase the oxidation resistance of uranium nitride (UN) nuclear fuel. These paths are: (1) Addition of USi{sub x} (e.g. U3Si2) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with various compounds (followed by densification via Spark Plasma Sintering or Liquid Phase Sintering) that will greatly increase oxidation resistance. The advantages (high thermal conductivity, very high melting point, and high density) of nitride fuel have long been recognized. The sodium cooled BR-10 reactor in Russia operated for 18 years on uranium nitride fuel (UN was used as the driver fuel for two core loads). However, the potential advantages (large power up-grade, increased cycle lengths, possible high burn-ups) as a Light Water Reactor (LWR) fuel are offset by uranium nitride's extremely low oxidation resistance (UN powders oxidize in air and UN pellets decompose in hot water). Innovative research is proposed to solve this problem and thereby provide an accident tolerant LWR fuel that would resist water leaks and high temperature steam oxidation/spalling during an accident. It is proposed that we investigate two methods to increase the oxidation resistance of UN: (1) Addition of USi{sub x} (e.g. U{sub 3}Si{sub 2}) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with compounds (followed by densification via Spark Plasma Sintering) that will greatly increase oxidation resistance