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Search Results: 1 - 10 of 12436 matches for " Graybill Christopher "
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Lymphocyte Depletion in Experimental Hemorrhagic Shock in Swine
Hawksworth Jason S,Graybill Christopher,Brown Trevor S,Gillern Suzanne M
Journal of Inflammation , 2012, DOI: 10.1186/1476-9255-9-34
Abstract: Background Hemorrhagic shock results in systemic activation of the immune system and leads to ischemia-reperfusion injury. Lymphocytes have been identified as critical mediators of the early innate immune response to ischemia-reperfusion injury, and immunomodulation of lymphocytes may prevent secondary immunologic injury in surgical and trauma patients. Methods Yorkshire swine were anesthetized and underwent a grade III liver injury with uncontrolled hemorrhage to induce hemorrhagic shock. Experimental groups were treated with a lymphocyte depletional agent, porcine polyclonal anti-thymocyte globulin (PATG) (n = 8) and compared to a vehicle control group (n = 9). Animals were observed over a 3 day survival period. Circulating lymphocytes were examined with FACS analysis for CD3/CD4/CD8, and central lymphocytes with mesenteric lymph node and spleen staining for CD3. Circulating and lung tissue16 infiltrating neutrophils were measured. Circulating CD3 lymphocytes in the blood and in central lymphoid organs (spleen/lymph node) were stained and evaluated using FACS analysis. Immune-related gene expression from liver tissue was quantified using RT-PCR. Results The overall survival was 22% (2/9) in the control and 75% (6/8) in the PATG groups, p = 0.09; during the reperfusion period (following hemorrhage) survival was 25% (2/8) in the control and 100% (6/6) in the PATG groups, p = 0.008. Mean blood loss and hemodynamic profiles were not significantly different between the experimental and control groups. Circulating CD3+CD4+ lymphocytes were significantly depleted in the PATG group compared to control. Lymphocyte depletion in the setting of hemorrhagic shock also significantly decreased circulating and lung tissue infiltrating neutrophils, and decreased expression of liver ischemia gene expression. Conclusions Lymphocyte manipulation with a depletional (PATG) strategy improves reperfusion survival in experimental hemorrhagic shock using a porcine liver injury model. This proof of principle study paves the way for further development of immunomodulation approaches to ameliorate secondary immune injury following hemorrhagic shock.
Lymphocyte Modulation with FTY720 Improves Hemorrhagic Shock Survival in Swine
Jason S. Hawksworth, J. Christopher Graybill, Trevor S. Brown, Shannon M. Wallace, Thomas A. Davis, Doug K. Tadaki, Eric A. Elster
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034224
Abstract: The inflammatory response to severe traumatic injury results in significant morbidity and mortality. Lymphocytes have recently been identified as critical mediators of the early innate immune response to ischemia-reperfusion injury. Experimental manipulation of lymphocytes following hemorrhagic shock may prevent secondary immunologic injury in surgical and trauma patients. The objective of this study is to evaluate the lymphocyte sequestration agent FTY720 as an immunomodulator following experimental hemorrhagic shock in a swine liver injury model. Yorkshire swine were anesthetized and underwent a grade III liver injury with uncontrolled hemorrhage to induce hemorrhagic shock. Experimental groups were treated with a lymphocyte sequestration agent, FTY720, (n = 9) and compared to a vehicle control group (n = 9). Animals were observed over a 3 day survival period after hemorrhage. Circulating total leukocyte and neutrophil counts were measured. Central lymphocytes were evaluated with mesenteric lymph node and spleen immunohistochemistry (IHC) staining for CD3. Lung tissue infiltrating neutrophils were analyzed with myeloperoxidase (MPO) IHC staining. Relevant immune-related gene expression from liver tissue was quantified using RT-PCR. The overall survival was 22.2% in the vehicle control and 66.7% in the FTY720 groups (p = 0.081), and reperfusion survival (period after hemorrhage) was 25% in the vehicle control and 75% in the FTY720 groups (p = 0.047). CD3+ lymphocytes were significantly increased in mesenteric lymph nodes and spleen in the FTY720 group compared to vehicle control, indicating central lymphocyte sequestration. Lymphocyte disruption significantly decreased circulating and lung tissue infiltrating neutrophils, and decreased expression of liver immune-related gene expression in the FTY720 treated group. There were no observed infectious or wound healing complications. Lymphocyte sequestration with FTY720 improves survival in experimental hemorrhagic shock using a porcine liver injury model. These results support a novel and clinically relevant lymphocyte immunomodulation strategy to ameliorate secondary immune injury in hemorrhagic shock.
Can Aging in Place Be Cost Effective? A Systematic Review
Erin M. Graybill, Peter McMeekin, John Wildman
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0102705
Abstract: Purpose of the Study To systematically review cost, cost-minimization and cost-effectiveness studies for assisted living technologies (ALTs) that specifically enable older people to ‘age in place’ and highlight what further research is needed to inform decisions regarding aging in place. Design People aged 65+ and their live-in carers (where applicable), using an ALT to age in place at home opposed to a community-dwelling arrangement. Methods Studies were identified using a predefined search strategy on two key economic and cost evaluation databases NHS EED, HEED. Studies were assessed using methods recommended by the Campbell and Cochrane Economic Methods Group and presented in a narrative synthesis style. Results Eight eligible studies were identified from North America spread over a diverse geographical range. The majority of studies reported the ALT intervention group as having lower resource use costs than the control group; though the low methodological quality and heterogeneity of the individual costs and outcomes reported across studies must be considered. Implications The studies suggest that in some cases ALTs may reduce costs, though little data were identified and what there were was of poor quality. Methods to capture quality of life gains were not used, therefore potential effects on health and wellbeing may be missed. Further research is required using newer developments such as the capabilities approach. High quality studies assessing the cost-effectiveness of ALTs for ageing in place are required before robust conclusion on their use can be drawn.
Assembly and Irradiation Modeling of Residual Stresses in Low-Enriched Uranium Foil-Based Annular Targets for Molybdenum-99 Production
Srisharan G. Govindarajan,Brian S. Graybill,Philip F. Makarewicz,Zhentao Xie,Gary L. Solbrekken
Science and Technology of Nuclear Installations , 2013, DOI: 10.1155/2013/673535
Abstract: This paper considers a composite cylindrical structure, with low-enriched uranium (LEU) foil enclosed between two aluminum 6061-T6 cylinders. A recess is cut all around the outer circumference of the inner tube to accommodate the LEU foil of open-cross section. To obtain perfect contact at the interfaces of the foil and the tubes, an internal pressure is applied to the inner tube, thereby plastically and elastically deforming it. The residual stresses resulting from the assembly process are used along with a thermal stress model to predict the stress margins in the cladding during irradiation. The whole process was simulated as a steady-state two-dimensional problem using the commercial finite element code Abaqus FEA. The irradiation behavior of the annular target has been presented, and the effect of the assembly residual stresses has been discussed. 1. Introduction The majority of the molybdenum-99 (Mo-99) produced internationally is extracted from high-enriched uranium (HEU) dispersion targets that have been irradiated. Mo-99 is the parent isotope of the radioactive tracer, technetium-99?m, which is used in medical imaging procedures. The high concentration U-235 in HEU-based targets makes them potential items of interest for rogue individuals. To alleviate the potential of proliferation issues, low-enriched uranium (LEU) targets are being mandated. Unfortunately the conversion of HEU- to LEU- based dispersion targets is accompanied by a reduction in Mo-99 production given today’s dispersion target technology. An increase in the density of uranium is needed in LEU-based targets in order to recover the loss in Mo-99 production per target [1]. One strategy to increase the uranium density is to use an LEU metal foil placed within the 6061-T6 aluminum cladding [2]. A second advantage of the LEU foil-based target is that it allows for the potential of the LEU foil to be removed after irradiation so that it can be dissolved by itself, reducing the liquid waste that would be generated by dissolving the entire target, including the 6061-T6 aluminum cladding. In this paper the aluminum 6061-T6 cladding will be simply referred to as “aluminum cladding.” The function of the target is to contain the fission products and to effectively dissipate the generated fission heat to the reactor coolant. For dispersion target designs there is generally little concern about heat getting dissipated to the coolant as the target structure offers little resistance to heat transfer. However, for the disassemble-able LEU foil target; there is a potential of the cladding to
What Role Can Propinquity Play in the Development of New National Allegiances? Immigrant Latinos Establishing Ties to the United States through Out-Group Contact  [PDF]
Christopher Olds
Advances in Applied Sociology (AASoci) , 2012, DOI: 10.4236/aasoci.2012.21002
Abstract: Contact theory has primarily been applied to the study of interactions between Blacks and Whites, with particular emphasis on changes in the attitudes of Whites towards Blacks. How individual contact with an out-group can influence not just attitudes, but also actual behavior, has not been thoroughly explored. Through an analysis of the 2006 Latino National Survey, using a measure that contrasts the intensity of individual social interaction with various ethnic and racial groups, the study shows that a high intensity of friendly social contact with African-Americans increases the likelihood Latino immigrants will establish a closer link to the social and political structures of the United States. Latino immigrants are potentially experiencing movement towards deprovincialization through high levels of friendly social interaction with African-Americans. The development of friendly personal interactions with an out-group stigmatized in the mother country can help Latino immigrants develop an optimistic view of life in the host country.
Net primary production and carbon cycling in coast redwood forests of central California  [PDF]
Christopher Potter
Open Journal of Ecology (OJE) , 2012, DOI: 10.4236/oje.2012.23018
Abstract: A simulation model to estimate net primary productivity (NPP) has been combined with in situ measurements of soil carbon dioxide (CO2) emissions and leaf litter pools in three coast redwood forest stands on the central California coast. Monthly NPP was predicted from the CASA model using 250-meter resolution vegetation index (VI) inputs. Annual NPP was predicted to vary from 380 g·C·m-2·yr-1 to 648 g·C·m-2·yr-1 at central coast redwood sites over the years 2007 to 2010. Measured soil respiration rates at between 0.5 to 2.2 g·C·m-2·d-1 were slightly below the range of measurements previously reported for a second-growth mixed (redwood and Douglas-fir) conifer forests. Although warm monthly temperatures at the southern-most redwood forest sites evidently results in elevated stress levels to sustained redwood growth into the dry summer months of June and July, these redwood stands appear to sequester CO2 from that atmosphere into forest biomass for a net positive ecosystem carbon balance each year.
Ten Years of Vegetation Change in Northern California Marshlands Detected Using Landsat Satellite Image Analysis  [PDF]
Christopher Potter
Journal of Water Resource and Protection (JWARP) , 2013, DOI: 10.4236/jwarp.2013.55048
Abstract:

The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detect changes in perennial vegetation cover at marshland sites in Northern California reported to have undergone restoration between 1999 and 2009. Results showed extensive contiguous areas of restored marshland plant cover at 10 of the 14 sites selected. Gains in either woody shrub cover and/or from a recovery of herbaceous cover that remains productive and evergreen on a year round basis could be mapped out from the image results. However, LEDAPS may not be highly sensitive changes in wetlands that have been restored mainly with seasonal herbaceous cover (e.g., vernal pools), due to the ephemeral nature of the plant greenness signal. Based on this evaluation, the LEDAPS methodology would be capable of fulfilling a pressing need for consistent, continual, low-cost monitoring of changes in marshland ecosystems of the Pacific Flyway.

Ex Post Efficient Set Mathematics  [PDF]
Christopher Adcock
Journal of Mathematical Finance (JMF) , 2013, DOI: 10.4236/jmf.2013.31A019
Abstract:

This paper considers efficient set mathematics for the case where the covariance matrix of asset returns is assumed known but ex ante the vector of expected returns is replaced by an estimated or forecast value. It is shown that the ex post mean and variance differ from the standard results. Consequently the maximum Sharpe ratio portfolio also differs from the standard result. However, even with uncertainty about the vector of expected returns, subject to the assumptions made about the joint distribution of actual returns and estimated mean returns, ex post Sharpe ratio maximisers hold the ex post market portfolio. The properties of the zero beta portfolio are similar to the standard results leading to a capital market line. The ex post Capital Asset Pricing Model incorporates an intercept and the betas are not the same as those computed ex ante. The results are illustrated with an example.

 

Mortality and motivations: Clinicians’ integrity engaging death within complex cultural context  [PDF]
Christopher Jenner
Open Journal of Nursing (OJN) , 2013, DOI: 10.4236/ojn.2013.31011
Abstract:

This broad ranging discussion examines the clinical encounter and deconstructs psychological and cultural context and implications, finally honoring the comprehensive awareness that the clinician requires for best practice in encountering mortality. Clinicians engage client disease and dying presentions, and ultimate mortality. Communicating mortality openly or subliminally is not always conscious. Mortality awareness can produce stress and untoward behaviors. Psychological mortality avoidance, citing Kierke-gaard’s existential paradox, and the death (in both senses) of Joseph Campbell’s cultural hero illumine socio-cultural elements including the elusive “good death”, sequestration of death from society, and the concept of managing death in volume. Cultural diversity awareness and the concept of transcendence clarify outlier and hybrid cultural client presentations demanding maximal clinician flexibility. Mortality Salience Theory predicts contracted world view when confronted with mortality, demanding sensitivity to a variety of responses. A hospice approach may not be best for some, despite a lack of new alternative to that paradigm. Managing mortality awareness and dying stresses the clinician by the weight and loneliness of perhaps unpopular decisions, by responsibility to community in managing death, and by the take-home exposure of the clinician’s family to the concept of death and mortality. Aptitude for managing death depends on clinician self awareness and a good match with practice venue. Clinician integrity and consciousness of motives and responses allows engagement or deferral as necessary without threat to identity.

Regional Analysis of NASA Satellite Greenness Trends for Ecosystems of Arctic Alaska  [PDF]
Christopher Potter
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.59085
Abstract:

Trends in the growing season MODerate resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) time-series were analyzed for the period from 2000 to 2010 to understand landscape-level patterns of vegetation change in ecosystems of arctic Alaska. We compared datasets for vegetation cover types, wetland cover classes, wildfire boundaries since the 1940s, permafrost type, and elevation to identify the most likely combination of factors driving regional changes in habitat quality and ecosystem productivity. Approximately 57% of all arctic ecosystem areas in Alaska were detected with significant (p < 0.05) positive or negative MODIS growing season EVI trends from 2000 to 2010. Nearly all (99%) of these ecosystem areas (covering 178,050 km2) were detected with significant positive growing season EVI trends. The vast majority of the arctic Alaska region detected with significant positive growing season EVI trends was classified as upland tundra cover, although non-forested wetlands (marshes, bogs, fens, and floodplains) were co-located on 8% of that area. Herbaceous wetlands were co-located on 55% of the total area detected with significant negative growing season EVI trends, mostly on the arctic coastal plain and foothills. This evidence supports the hypothesis that temperature (warming) has markedly enhanced the rates of upland tundra vegetation growth across most of arctic Alaska over recent years.

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