1,041 research outputs found

    Effect of debris size on the tribological performance of thermally sprayed coatings

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    This research aims to assess the effect of the debris particle size on the tribological performance and lubrication regime parameters of a Ni-based alloy coating. This is a key industrial problem, and its resolution can contribute to better machine endurance and proper maintenance. The debris particles are simulated by hard Al2O3 particles of size ranging from nanometers to 45 μm and dispersed in an oil lubricant. The coating studied is NiCrBSi deposited by flame spraying technique followed by the Surface Flame Melting (SFM) process. The counterpart disk sample was fabricated from quenched and tempered F-5220 steel (in line with A681(O1) ASTM). This pair was tested under linear sliding contact. Our results show that the addition of alumina particles contributes to a significant increase in wear, particularly for the largest particles (micrometric size). In the case of micrometric particles, it is possible to observe the formation of higher surface roughness, numerous microgrooves, and plastic flow of NiCrBSi coating perpendicular to the sliding direction, resulting in higher loss of volume. It was found that the actual surface roughness (obtained as a function of the debris particle size) allows better identification and prediction of the lubrication regime for wear processes instead of the traditional approach that uses the initial surface roughness as a parameter

    Voltammetry as a rapid screening method for NPS identification

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    Designer drugs, also commonly known as new psychoactive substances (NPS), are increasingly in their prevalence and a challenge to toxicologists and forensic chemists. Synthetic cannabinoids (SCs) are among the largest group of NPS that have emerged in the illicit drug market all over the world. SCs may consist of different chemicals prepared in laboratories and herbal mixtures that said to be incense and not-for-human-consumption. The main aim of this paper is to investigate the use of electrochemical based methods for screening some of the emerging types of SC. More specifically, the paper takes electrochemistry approach called voltammetry to perform the detection and analysis of SCs whereby the main subjects for screening include STS-135 and 5F-ADB-PINACA. The expected result is that those compounds that belong to the same class should indicate almost similar behaviour to help achieve its objective, the paper reviews a number of recent publications relating to forensic drug analysis and much attention to electrochemical sensor methods

    Effect of fire smoke on some biochemical parameters in firefighters of Saudi Arabia

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    <p>Abstract</p> <p>Background</p> <p>Firefighters who are facing fires, are frequently exposed to hazardous materials including carbon monoxide, hydrogen cyanide, hydrogen chloride, benzene, sulphur dioxide, etc. This study aimed to evaluate some relevant serum biochemical and blood hematological changes in activity involved firefighters in comparison to normal subjects.</p> <p>Subjects and Methods</p> <p>Two groups of male firefighters volunteered to participate in the study. The first included 28 firefighters from Jeddah, while the second included 21 firefighters from Yanbu, with overall age ranged 20–48 years. An additional group of 23 male non-firefighters volunteered from both cities as normal control subjects, of age range 20–43 years. Blood samples were collected from all volunteer subjects and investigated for some relevant serum biochemical and blood hematological changes.</p> <p>Results</p> <p>The results obtained showed that, there were statistically significant differences in liver function, kidney function, serum lipid profile, cortisol, creatine kinase, lactate dehydrogenase, iron and its biologically active derivatives, and blood picture in firefighters as compared with the normal control group. These results indicate that, fire smoke mainly affects serum biochemical and blood hematological parameters. Such results might point out to the need for more health protective and prophylactic measures to avoid such hazardous health effects that might endanger firefighters under their highly drastic working conditions.</p> <p>Conclusion</p> <p>Besides using of personal protective equipments for firefighters to protect them against exposure to toxic materials of fire smoke, it is recommended that, firefighters must be under continuous medical follow up through a standard timetabled medical laboratory investigations to allow for early detection of any serum biochemical or blood hematological changes that might happen during their active service life and to allow for early treatment whenever necessary.</p

    Harris lines of the tibia across centuries: a comparison of two populations, medieval and contemporary in Central Europe

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    Objective: To determine the incidence of Harris lines in two medieval populations which inhabited the Canton of Berne, in Central Switzerland, and to compare the results with those of a contemporary population living in the same geographical area. A simplified method is described for measuring the age of the individual at the time of formation of Harris lines, with possible future applications. Design and patients: Radiographs of 112 well-preserved tibiae of skeletons of two medieval populations from the eighth to fifteenth centuries were reviewed for the incidence of Harris lines. The results were compared with those of 138 current patients living in the same geographic location in Central Switzerland. Age and gender of the medieval individual were determined using known anthropological methods. Age of bone at the time of formation of Harris lines was estimated according to the method of Maat. Results: Harris lines were found in 88 of 112 (80%) of the examined medieval skeletons and in 28 of 138 (20%) of the living individuals. Higher incidences of Harris lines were found at the age of 2years and at ages between 8 and 12years in both populations. No gender difference was found regarding the incidence of Harris lines. In both populations the occurrence of Harris lines was associated with certain diseases such as degenerative bone disease, trauma, osteoporosis, rheumatoid arthritis, peripheral vascular diseases, rickets and bony deformities. Conclusion: A high incidence of Harris lines was found in the medieval population, perhaps reflecting difficult living and hygienic conditions, but also the poor care and neglect of the children population. Measuring the age of the individual at the time of formation of Harris lines is simple and may have future clinical applications in the paediatric population for medico-legal purposes. The application of Harris lines as a marker in follow-up of osteoporosis may need further evaluatio

    Bioactive metabolites in improved cowpea seeds

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    The International Institute of Tropical Agriculture (IITA) has developed some pest and disease resistant cowpeas. From these the seeds of 8 cowpea cultivars were extracted with ethanol, and partitioned into chloroform and water-soluble fractions, the water-soluble fraction was further extracted with ethyl acetate. Residues from ethanol, chloroform and ethyl acetate soluble fractions for each of the 8 cowpea cultivars were screened against brine shrimp larvae. The seed extracts of cowpea cultivars IT93K – 596 – 9 – 12, IT90K – 277 – 2 and IT93K – 452 – 1 were found to be most active, indicating that they contain cytotoxic compound(s).African Journal of Biotechnology Vol. 4 (6), pp. 513-516, 200

    Structural Heat Intercept, Insulation and Vibration Evaluation Rig (SHIIVER)

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    The Structural Heat Intercept, Insulation, and Vibration Evaluation Rig (SHIIVER) is a large scale cryogenic fluid management (CFM) test bed designed to scale CFM technologies for inclusion on large, in-space stages. A part of the evolvable Cryogenics (eCryo) project, SHIIVER is a technology development task that is supportive of future exploration propulsion needs. Technologies developed under the eCryo Project will play a critical role in enabling increasingly longer duration in-space missions beyond Low Earth Orbit (LEO)

    Health Information-Seeking Behavior of Seniors Who Use the Internet:A Survey

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    Background: The Internet is viewed as an important source for health information and a medium for patient empowerment. However, little is known about how seniors use the Internet in relation to other sources for health information.Objective: The aim was to determine which information resources seniors who use the Internet use and trust for health information, which sources are preferred, and which sources are used by seniors for different information needs.Methods: Questions from published surveys were selected based on their relevance to the study objectives. The Autonomy Preference Index was used to assess information needs and preferences for involvement in health decisions. Invitation to participate in this online survey was sent to the email list of a local senior organization (298 addresses) in the Netherlands.Results: There were 118 respondents with a median age of 72 years (IQR 67-78 years). Health professionals, pharmacists, and the Internet were the most commonly used and trusted sources of health information. Leaflets, television, newspapers, and health magazines were also important sources. Respondents who reported higher use of the Internet also reported higher use of other sources (PConclusions: For these seniors who use the Internet, the Internet was a preferred source of health information. Seniors who report higher use of the Internet also report higher use of other information resources and were also the primary consumers of paper-based resources. Respondents most frequently searched for health information after an appointment rather than to prepare for an appointment. Resources used varied by health topic. Future research should seek to confirm these findings in a general elderly population, investigate how seniors seek and understand information on the Internet, and investigate how to reach seniors who prefer not to use the Internet for health information.</p

    Influence of Al2O3 Particle Size on Microstructure, Mechanical Properties and Abrasive Wear Behavior of Flame-Sprayed and Remelted NiCrBSi Coatings

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    The influence of micrometric alumina (low surface area-to-volume ratio) and nanometric alumina (high surface area-to-volume ratio) on microstructure, hardness and abrasive wear of a NiCrBSi hardfacing alloy coating applied to an AISI 304 substrate using flame spraying (FS) combined with surface flame melting (SFM) is studied. Remelting after spraying improved the mechanical and tribological properties of the coatings. Microstructural characterization using XRD, SEM and EDS indicated that alumina additions produced similar phases (NiSi, Ni3B, CrC and Ni31Si12) regardless of the alumina size, but the phases differed in morphology, size distribution and relative proportions from one coating to another. The addition of 12 wt.% nanometric Al2O3 increased the phases concentration more than five- to sixfold and reduced the hard phases size about four-to threefold compared with NiCrBSi + 12 wt.% micrometric Al2O3. Nanoalumina led to reduced mass loss during abrasive wear compared to micrometric alumina and greater improvement in hardness

    Can harmonisation of outcomes bridge the translation gap for pre-clinical research? A systematic review of outcomes measured in mouse models of type 2 diabetes

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    Background: In pre-clinical research, systematic reviews have the potential to mitigate translational challenges by facilitating understanding of how pre-clinical studies can inform future clinical research. Yet their conduct is encumbered by heterogeneity in the outcomes measured and reported, and those outcomes may not always relate to the most clinically important outcomes. We aimed to systematically review outcomes measured and reported in pre-clinical in vivo studies of pharmacological interventions to treat high blood glucose in mouse models of type 2 diabetes. Methods: A systematic review of pre-clinical in vivo studies of pharmacological interventions aimed at addressing elevated blood glucose in mouse models of type 2 diabetes was completed. Studies were screened for eligibility and outcomes extracted from the included studies. The outcomes were recorded verbatim and classified into outcome domains using an existing outcome taxonomy. Outcomes were also compared to those identified in a systematic review of registered phase 3/4 clinical trials for glucose lowering interventions in people with type 2 diabetes. Results: Review of 280 included studies identified 532 unique outcomes across 19 domains. No single outcome, or domain, was measured in all studies and only 132 (21%) had also been measured in registered phase 3/4 clinical trials. A core outcome set, representing the minimum that should be measured and reported, developed for type 2 diabetes effectiveness clinical trials includes 18 core outcomes, of these 12 (71%) outcomes were measured and reported in one or more of the included pre-clinical studies. Conclusions: There is heterogeneity of outcomes reported in pre-clinical research. Harmonisation of outcomes across the research pathway using a core outcome set may facilitate interpretation, evidence synthesis and translational success, and may contribute to the refinement of the use of animals in research. Systematic review registration: The study was prospectively registered on the PROSPERO Database, registration number CRD4201810683
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