557 research outputs found

    Risks Posed by Reston, the Forgotten Ebolavirus

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    Out of the five members of the Ebolavirus family, four cause lifethreatening disease, whereas the fifth, Reston virus (RESTV), is nonpathogenic in humans. The reasons for this discrepancy remain unclear. In this review, we analyze the currently available information to provide a state-of-the-art summary of the factors that determine the human pathogenicity of Ebolaviruses. RESTV causes sporadic infections in cynomolgus monkeys and is found in domestic pigs throughout the Philippines and China. Phylogenetic analyses revealed that RESTV is most closely related to the Sudan virus, which causes a high mortality rate in humans. Amino acid sequence differences between RESTV and the other Ebolaviruses are found in all nine Ebolavirus proteins, though no one residue appears sufficient to confer pathogenicity. Changes in the glycoprotein contribute to differences in Ebolavirus pathogenicity but are not sufficient to confer pathogenicity on their own. Similarly, differences in VP24 and VP35 affect viral immune evasion and are associated with changes in human pathogenicity. A recent in silico analysis systematically determined the functional consequences of sequence variations between RESTV and human-pathogenic Ebolaviruses. Multiple positions in VP24 were differently conserved between RESTV and the other Ebolaviruses and may alter human pathogenicity. In conclusion, the factors that determine the pathogenicity of Ebolaviruses in humans remain insufficiently understood. An improved understanding of these pathogenicity-determining factors is of crucial importance for disease prevention and for the early detection of emergent and potentially human-pathogenic RESTVs

    Investigating summer thermal stratification in Lake Ontario

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    Summer thermal stratification in Lake Ontario is simulated using the 3D hydrodynamic model Environmental Fluid Dynamics Code (EFDC). Summer temperature differences establish strong vertical density gradients (thermocline) between the epilimnion and hypolimnion. Capturing the stratification and thermocline formation has been a challenge in modeling Great Lakes. Deviating from EFDC's original Mellor-Yamada (1982) vertical mixing scheme, we have implemented an unidimensional vertical model that uses different eddy diffusivity formulations above and below the thermocline (Vincon-Leite, 1991; Vincon-Leite et al., 2014). The model is forced with the hourly meteorological data from weather stations around the lake, flow data for Niagara and St. Lawrence rivers; and lake bathymetry is interpolated on a 2-km grid. The model has 20 vertical layers following sigma vertical coordinates. Sensitivity of the model to vertical layers' spacing is thoroughly investigated. The model has been calibrated for appropriate solar radiation coefficients and horizontal mixing coefficients. Overall the new implemented diffusivity algorithm shows some successes in capturing the thermal stratification with RMSE values between 2-3°C. Calibration of vertical mixing coefficients is under investigation to capture the improved thermal stratification

    Hydrophilic titanium surface‐induced macrophage modulation promotes pro‐osteogenic signalling

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    Objectives: As biomaterial‐induced modulation of mediators of the immune response may be a potential therapeutic approach to enhance wound healing events, the aim of this study was to delineate the effects of titanium surface modification on macrophage phenotype and function. Material and methods: Rodent bone marrow‐derived macrophages were polarized into M1 and M2 phenotypes and cultured on micro‐rough (SLA) and hydrophilic modified SLA (modSLA) titanium discs. Macrophage phenotype and cytokine secretion were subsequently assessed by immunostaining and ELISA, respectively. Osteoblast gene expression in response to culture in the M1 and M2 macrophage conditioned media was also evaluated over 7 days by RT‐PCR. Results: M1 macrophage culture on the modSLA surface promoted an M2‐like phenotype as demonstrated by marked CD163 protein expression, Arg1 gene expression and the secretion of cytokines that significantly upregulated in osteoblasts the expression of genes associated with the TGF‐ß/BMP signalling pathway and osteogenesis. In comparison, M2 macrophage culture on SLA surface promoted an inflammatory phenotype and cytokine profile that was not conducive for osteogenic gene expression. Conclusions: Macrophages are able to alter or switch their phenotype according to the signals received from the biomaterial surface. A hydrophilic micro‐rough titanium surface topography elicits a macrophage phenotype associated with reduced inflammation and enhanced pro‐osteogenic signalling

    Numerical modeling of thermal bar and stratification pattern in Lake Ontario using the EFDC model

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    Thermal bar is an important phenomenon in large, temperate lakes like Lake Ontario. Spring thermal bar formation reduces horizontal mixing, which in turn, inhibits the exchange of nutrients. Evolution of the spring thermal bar through Lake Ontario is simulated using the 3D hydrodynamic model Environmental Fluid Dynamics Code (EFDC). The model is forced with the hourly meteorological data from weather stations around the lake, flow data for Niagara and St. Lawrence rivers, and lake bathymetry. The simulation is performed from April to July, 2011; on a 2-km grid. The numerical model has been calibrated by specifying: appropriate initial temperature and solar radiation attenuation coefficients. The existing evaporation algorithm in EFDC is updated to modified mass transfer approach to ensure correct simulation of evaporation rate and latent heatflux. Reasonable values for mixing coefficients are specified based on sensitivity analyses. The model simulates overall surface temperature profiles well (RMSEs between 1-2°C). The vertical temperature profiles during the lake mixed phase are captured well (RMSEs < 0.5°C), indicating that the model sufficiently replicates the thermal bar evolution process. An update of vertical mixing coefficients is under investigation to improve the summer thermal stratification pattern. Keywords: Hydrodynamics, Thermal BAR, Lake Ontario, GIS

    Persistent colonization with Tannerella forsythensis and loss of attachment in adolescents

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    Colonization with Tannerella forsythensis may characterize the conversion of periodontally healthy sites into diseased sites. This three-year study describes the prevalence of T forsythensis and its relationship to clinical loss of attachment (LOA) in a group of adolescents considered at risk of developing early chronic periodontitis. Adolescents with (LOA+) and without (LOA-) loss of attachment were examined at baseline and 1.5 and 3 yrs subsequently. On each occasion, attachment loss was measured on selected teeth, and the presence of T. forsythensis in their subgingival plaque samples was determined by PCR. T. forsythensis prevalence in LOA+ subjects at baseline (64%) increased to 82% and 86% on subsequent examinations. In contrast, prevalence of T. forsythensis in LOA- subjects was always significantly lower (25%, 36%, and 32%, respectively). The odds of loss of attachment were 8.16 times greater in subjects infected with T. forsythensis at each examination. These results suggest that T. forsythensis is strongly associated with loss of attachment in this adolescent population

    Assessment of reporting quality of conference abstracts in sports injury prevention according to CONSORT and STROBE criteria and their subsequent publication rate as full papers

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    <p>Abstract</p> <p>Background</p> <p>The preliminary results of a study are usually presented as an abstract in conference meetings. The reporting quality of those abstracts and the relationship between their study designs and full paper publication rate is unknown. We hypothesized that randomized controlled trials are more likely to be published as full papers than observational studies.</p> <p>Methods</p> <p>154 oral abstracts presented at the World Congress of Sports Injury Prevention 2005 Oslo and the corresponding full paper publication were identified and analysed. The main outcome measures were frequency of publication, time to publication, impact factor, CONSORT (for Consolidated Standards of Reporting Trials) score, STROBE (for Strengthening the Reporting of Observational Studies in Epidemiology) score, and minor and major inconsistencies between the abstract and the full paper publication.</p> <p>Results</p> <p>Overall, 76 of the 154 (49%) presented abstracts were published as full papers in a peer-reviewed journal with an impact factor of 1.946 ± 0.812. No significant difference existed between the impact factor for randomized controlled trials (2.122 ± 1.015) and observational studies (1.913 ± 0.765, p = 0.469). The full papers for the randomized controlled trials were published after an average (SD) of 17 months (± 13 months); for observational studies, the average (SD) was 12 months (± 14 months) (p = 0.323). A trend was observed in this study that a higher percentage of randomized controlled trial abstracts were published as full papers (71% vs. 47%, p = 0.078) than observational trials. The reporting quality of abstracts, published as full papers, significantly increased compared to conference abstracts both in randomized control studies (CONSORT: 5.7 ± 0.7 to 7.2 ± 1.3; p = 0.018, CI -2.7 to -0.32) and in observational studies (STROBE: 8.2 ± 1.3 to 8.6 ± 1.4; p = 0.007, CI -0.63 to -0.10). All of the published abstracts had at least one minor inconsistency (title, authors, research center, outcome presentation, conclusion), while 65% had at least major inconsistencies (study objective, hypothesis, study design, primary outcome measures, sample size, statistical analysis, results, SD/CI). Comparing the results of conference and full paper; results changed in 90% vs. 68% (randomized, controlled studies versus observational studies); data were added (full paper reported more result data) in 60% vs. 30%, and deleted (full paper reported fewer result data) in 40% vs. 30%.</p> <p>Conclusions</p> <p>No significant differences with respect to type of study (randomized controlled versus observational), impact factor, and time to publication existed for the likelihood that a World Congress of Sports Injury conference abstract could be published as a full paper.</p

    Bisphosphonate-related osteonecrosis of jaw (BRONJ): diagnostic criteria and possible pathogenic mechanisms of an unexpected anti-angiogenic side effect.

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    Recently, bisphosphonates (BPs) have been widely used in medical practice as anti-resorptive agents owing to their anti-osteoclatic action. In addition, these compounds are also used for their analgesic action and their potential anti-tumour effect. Patients treated with BPs may subsequently develop osteonecrosis of the jaw or maxillary bone after minor local trauma including dental work, recently labelled as bisphosphonate osteonecrosis of jaw (BRONJ). However, the etiopathogenic mechanisms of this pathological condition are poorly understood. Although, several pathways have been proposed for BRONJ occurrence, no single model can explain all morphological changes observed at the macro- and microscopic level. Recent research suggests that BPs may promote an anti-angiogenic effect which contributes directly to the clinical features associated with BRONJ. Remarkably, the anti-angiogenic effect promoting BRONJ might be in keeping with the anti-neoplastic action of BPs. The current review, presents clinical diagnostic criteria. In addition, based on our own experience we describe the histopathological criteria for diagnosis of BRONJ and the possible pathways which may lead to this frustrating pathological condition

    Relative influences of human nutrient sources, the Pacific Ocean, and climate change on Salish Sea dissolved oxygen through 2070

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    The Department of Ecology and Pacific Northwest National Laboratory evaluated future dissolved oxygen scenarios within the Salish Sea using a circulation and water quality model of Puget Sound, the Strait of Georgia, and the Strait of Juan de Fuca. A recently published report summarizes relative contributions of human nutrient sources, the Pacific Ocean, and climate factors on dissolved oxygen both now and through 2070. Human nitrogen contributions from the U.S. and Canada to the Salish Sea have the greatest impacts on dissolved oxygen in portions of South and Central Puget Sound. Marine point sources cause greater impacts on oxygen than human influences on river inflows now and into the future. Most of the Salish Sea reflects a relatively low impact from human sources, although that will increase as loads increase. The Pacific Ocean strongly influences dissolved oxygen concentrations under both current and future conditions. If 50-year declining trends in North Pacific Ocean dissolved oxygen continue, Salish Sea dissolved oxygen would decline far more than from human nutrient loads. Climate change will alter the timing of freshwater flow reaching the Salish Sea, as provided by the University of Washington Climate Impacts Group. This would alter estuarine circulation patterns, potentially worsening impacts in some regions but lessening others. Future air temperature increases would further decrease dissolved oxygen, particularly in shallow inlets. This is the first assessment of how Salish Sea dissolved oxygen concentrations respond to population increases, ocean conditions, and climate change. Additional analyses are needed to link sediment-water interactions and increase scientific certainty
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