23 research outputs found
Cumulative Distribution of Ballistic Impact Failures of Common Twisted-Pair Data Cables at Orbital Speeds
Data wire cable runs are a significant presence on the exterior of the International Space Station (ISS), and continued ISS mission support requires detailed assessment of cables due to micrometeoroid and orbit debris (MMOD) impact. These data wire cables are twisted-pair cables consisting of two 22AWG stranded conductors and fillers inside a tight fitting braided copper shield. The copper shield and its contents are covered with a jacket that has a nominal outer diameter of 3.76 mm and beta-cloth tape. The ISS engineering community has identified two loss-of-function mechanisms for these cables: open circuits due to severed conductors within the cable, and short circuits due to contact between conductors or grounded components. As these data cables are low power systems, short circuits are not expected to burn away the contact, so both open and short circuits are considered permanent loss-of-function for the cable. A total of ninety-seven impact experiments have been performed into these cables to develop a statistical model for the failure of these cables to be used in reliability studies. The experimental work has yielded cumulative distribution functions for these cables for steel and aluminum components of the orbital debris environment at representative speeds and impact obliquities
Exploring New Models for Cardiovascular Risk Reduction: The Heart Outcomes Prevention and Evaluation 4 (HOPE 4) Canada Pilot Study.
BACKGROUND: There is a gap between evidence and practice in the management of cardiovascular (CV) risk. Previous research indicated benefits from community-based, multi-faceted interventions to screen, diagnose, and manage CV risk in people with hypertension. METHODS: The Heart Outcomes Prevention and Evaluation 4 Canada pilot study (HOPE 4) was a quasi-experimental pre-post interventional study, involving one community each in Hamilton, Ontario and Surrey, British Columbia, Canada. Individuals aged ≥50 years with newly diagnosed or poorly controlled hypertension were included. The intervention was comprised of: (i) simplified diagnostic/treatment algorithms implemented by community health workers (firefighters in British Columbia and community health workers in Ontario) guided by decision support and counselling software; (ii) recommendations for evidence-based CV medications and lifestyle modifications; and (iii) support from family/friends to promote healthy behaviours. The intervention was developed as part of the international Heart Outcomes Prevention and Evaluation 4 Canada pilot study trial and adapted to the Canadian context. The primary outcome was the change in Framingham Risk Score 10-year CV disease risk estimate between baseline and 6 months. RESULTS: Between 2016 and 2017, a total of 193 participants were screened, with 37 enrolled in Surrey, and 19 in Hamilton. Mean age was 69 years (standard deviation 11), with 54% female, 27% diabetic, and 73% with a history of hypertension. An 82% follow-up level had been obtained at 6 months. Compared to baseline, there were significant improvements in the Framingham Risk Score 10-year risk estimate (30.6% vs 24.7%, P < 0.01), and systolic blood pressure (153.1 vs 136.7 mm Hg, P < 0.01). No significant changes in lipids or healthy behaviours were noted. CONCLUSIONS: A comprehensive approach to health care delivery, using a community-based intervention with community health workers, supported by mobile-health technologies, has the potential to significantly reduce cardiovascular risk, but further evaluation is warranted
Targeted Transcriptome Analysis of Beef Cattle Persistently Infected with Bovine Viral Diarrhea Virus
Background: Bovine viral diarrhea virus (BVDV) is an endemic virus of North American cattle populations with significant economic and animal health impacts. While BVDV infection has a myriad of clinical manifestations, a unique and problematic outcome is the establishment of a persistently infected (PI) animal following in utero viral infection. While it is well established that PI animals serve as a constant reservoir of BVDV, the mechanism for the maintained infection remains unknown despite multiple theories. Objective: The purpose of this study was to use transcriptome analysis to investigate the long-term immune status of adult PI cattle and offer insight into the potential mechanistic establishment of persistent BVDV infection. Methods: Peripheral blood mononuclear cells were collected from PI beef cattle (N = 6) and controls (N = 6) for targeted RNAseq analysis using 54 immune-related genes followed by pathway enrichment analysis. Results: Analysis revealed 29 differentially expressed genes (FDR < 0.05, fold change ≥ 2), representing 14 significant KEGG pathways between groups (FDR < 0.05). Transcriptome changes indicated chronic upregulation of interferon-gamma (IFNG) with an unexpected expression of related genes. Conclusions: These results provide novel insight into understanding the adult PI immune system and indicate maintained stimulation resulting from virus-mediated dysregulation
Biofilm Bacterial Community Structure in Streams Affected by Acid Mine Drainage▿ †
We examined the bacterial communities of epilithic biofilms in 17 streams which represented a gradient ranging from relatively pristine streams to streams highly impacted by acid mine drainage (AMD). A combination of automated ribosomal intergenic spacer analysis with multivariate analysis and ordination provided a sensitive, high-throughput method to monitor the impact of AMD on stream bacterial communities. Significant differences in community structure were detected among neutral to alkaline (pH 6.7 to 8.3), acidic (pH 3.9 to 5.7), and very acidic (pH 2.8 to 3.5) streams. DNA sequence analysis revealed that the acidic streams were generally dominated by bacteria related to the iron-oxidizing genus Gallionella, while the organisms in very acidic streams were less diverse and included a high proportion of acidophilic eukaryotes, including taxa related to the algal genera Navicula and Klebsormidium. Despite the presence of high concentrations of dissolved metals (e.g., Al and Zn) and deposits of iron hydroxide in some of the streams studied, pH was the most important determinant of the observed differences in bacterial community variability. These findings confirm that any restoration activities in such systems must focus on dealing with pH as the first priority
The in vivo and in vitro metabolic profile of 99mTc-NC100668, a new tracer for imaging venous thrombo-embolism: Identification and biodistribution of the principal radiolabelled metabolite
99mTc-NC100668, an agent for imaging venous thromboembolism : The effect of anticoagulant or thrombolytic therapy on the uptake and retention of radioactivity in blood clots in vivo
BACKGROUND: The purpose of this study was to evaluate the uptake of Tc-NC100668 into blood clots and elucidate the potential for medications commonly used to treat thromboembolism to interfere with the uptake and retention of Tc-NC100668. METHODS: Tc-NC100668 in vivo uptake and retention in a range of blood clot of various ages (up to 4 h old) and in the presence of anticoagulants or thrombolytic therapies was measured in a rat model of deep vein thrombosis. RESULTS: Tc-NC100668 was rapidly absorbed into and retained by blood clots and was not significantly affected by the presence of unfractionated or low molecular weight heparin or thrombin inhibitor. Tissue plasminogen activator reduced the uptake of Tc-NC100668 into blood clot by a factor of 3 when adjusted to allow for changes in the weight of the blood clot. CONCLUSIONS: This study has demonstrated that the uptake and retention of Tc-NC100668 into blood clots in the rat model of deep vein thrombosis is rapid and maintained over at least a 4 h post-injection period. It has been shown that Tc-NC100668 is retained in blood clots even in the presence of therapeutic doses of those anticoagulant and thrombolytic therapies typically used to treat pulmonary embolism and venous thrombosis.</p
The biodistribution of NC100668 and the effect of excess NC100668 on the biodistribution and kidney retention of Tc-99m-NC100668 in the rat
INTRODUCTION: (99m)Tc-NC100668 is being developed to aid the diagnosis of thromboemboli. The purpose of this study was to investigate if the presence of excess NC100668 interferes with the biodistribution and blood clot uptake of (99m)Tc-NC100668. The secondary aim was to investigate the causes underlying the kidney retention of (99m)Tc-NC100668. METHODS: The uptake of a (14)C-labelled analogue of NC100668, as well as (99m)Tc-NC100668, into plasma (in vitro) and blood (in vivo) clots was determined. The biodistribution of (99m)Tc-NC100668 at a range of NC100668 doses was studied in normal Wistar rats and those bearing experimentally induced deep venous thrombosis. The biodistribution of a negative control peptide and (99m)Tc-NC100668 plus L-lysine was studied in healthy male Wistar rats. RESULTS: The biodistribution as well as plasma clot uptake of [Asn-U-(14)C]NC100668 and (99m)Tc-NC100668 was similar. Apart from some reduction in kidney retention, the biodistribution and uptake of radioactivity into the blood clot were not significantly affected by the presence of up to 1000 times the clinical dose of NC100668. Kidney retention of radioactivity could be more effectively reduced by coadministration of 889 microg/kg NC100668 than 450 mg/kg L-lysine. A negative control peptide with no affinity for FXIIIa demonstrated very little kidney retention. CONCLUSIONS: The biodistribution and blood clot uptake of (99m)Tc-NC100668 and [Asn-U-(14)C]NC100668 are similar. With the exception of the kidneys, (99m)Tc-NC100668 biodistribution and blood clot uptake are unaffected by the presence of unlabelled NC100668. The kidney retention of radioactivity is probably due to transglutaminase activity and, to a lesser extent, nonspecific charge-mediated endocytosis.</p
Surface and subsurface fault mapping in the Yorkshire Wolds, UK
&lt;p&gt;The Flamborough Head Fault Zone (FHFZ) marks the southern extent of the Cleveland Basin and the northern margin of the Market Weighton Block, England. It is a regionally-significant structural zone which has undergone a complex history of Mesozoic-Cenozoic extension and compression. It is predominantly comprised of east-west trending faults which form a graben that is dissected by north-south trending faults, including the southern extension to the Peak Trough, the Hunmanby Fault. To the west, FHFZ links with the Howardian Fault System and offshore, in the east, it is truncated by the north-south trending Dowsing Fault. The FHFZ is well exposed and described from coastal cliff sections at Flamborough Head but the inland development of the faults have hitherto been poorly explored predominantly due to limited inland-exposure.&lt;/p&gt;&lt;p&gt;The region around the FHFZ is underlain by the Chalk Group, a 500&amp;#160;m thick limestone succession. The Chalk Group is a principal aquifer that is the main source of water supply in East Yorkshire. The geometry and physical characteristics of the Chalk succession, including the effects of faulting, influence groundwater flow across the region. A range of modern data and recent geological research highlight that considerable changes can be made to the region&amp;#8217;s current geological maps and subsurface understanding. Ensuring these features are better-documented is key for up-dating groundwater models to enable more confident decisions about land-use, water management and environmental regulation.&lt;/p&gt;&lt;p&gt;A multi-faceted approach to geological mapping has been undertaken in the region by the British Geological Survey (BGS), in collaboration with the Environment Agency. Remote sensing and field mapping of the superficial deposits has better characterised the extent and nature of these deposits and identified potential recharge &amp;#8216;windows&amp;#8217; into the bedrock. Remote sensing, targeted field mapping, palaeontological analysis, passive seismic and 2D onshore seismic interpretation have been integrated to produce a new map of the Chalk succession, which reveals the inland extension of the FHFZ in unprecedented detail. Combining these techniques has enabled us to bridge the gap between the surface geology and deeper subsurface structure, increase our understanding of the geology of the region and produce an improved conceptual model at a range of depths which will be used to better manage water resources.&lt;/p&gt;
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