234 research outputs found

    Computer programs to model three dimensional structure of the MMC

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    Abstract This study presents two computer programs contributing to the spatial description of the composite alloy structure. In one program the structure of an alloy suspension composite is generated (reinforced with SiC particles) on the basis of the results of metallographic measurements, while the other program visualizes the model obtained in the pseudo-3D space. The work is part of research aimed at the description of quality parameters of metallic composites

    Properties of Sonochemically Prepared CuInxGa1-xS2 and CuInxGa1-xSe2

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    Nanoparticles of chalcopyrites copper indium gallium sul de (CuInxGa1xS2 or CIGS) and copper indium gallium selenide (CuInxGa1xSe2 or CIGSe) were fabricated sonochemically. They were characterized by Xray di raction, scanning electron microscopy, energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy, selected area electron di raction, and di use re ectance spectroscopy. The electrical and photoelectrical properties of the fabricated nanomaterials were investigated

    Abrasion Resistance of S235, S355, C45, AISI 304 and Hardox 500 Steels with Usage of Garnet, Corundum and Carborundum Abrasives

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    В статті містяться результати випробувань основних типів сталей при терті по нежорстко закріплених частинках абразивуВ статье содержаться результаты испытаний основных типов сталей при трении о нежостко закрепленные абразивные частицыThe article contains the results of tests of the main types of steels by friction on non-rigidly fixed abrasive particles. The steel presents a wide field of application. The abrasive wear resistance of steel relies mainly on the microstructure, hardness as well as on the abrasive material properties. Moreover, the selection of a abrasion-resistant grade of steel still seems to be a crucial and unsolved problem, especially due to the fact that the actual operating conditions can be affected by the presence of different abrasive materials. The aim of this work was to determine the effect of different abrasive grit materials i.e. garnet, corundum and carborundum on the abrasive wear result of a commonly used in industry practice steels i.e. S235, S355, C45, AISI 304 and Hardox 500. The microstructure of the steel was investigated using light optical microscopy. Moreover, hardness was measured with Vickers hardness tester. Additionally, the size and morphology of the abrasive materials were characterized. The abrasion tests were conducted with the usage of T-07 tribotester (dry sand rubber wheel). The results demonstrate that the hardness and structure of steels and hardness of abrasive grids influenced the wear results. The abrasive wear behavior of steels was dominated by microscratching and microcutting wear mechanisms. The highest mass loss was obtained for garnet, corundum, and carborundum, respectively. The usage of various abrasives results in different abrasion resistance for each tested steel grade. The AISI 304 austenitic stainless steel presents an outstanding abrasive wear resistance while usage of corundum and Hardox 500 while using a garnet as abrasive material. The C45 carbon steel was less resistant than AISI 304 for all three examined abrasives. The lowest resistance to wear in garnet and carborundum was obtained for the S235JR and S355J2 ferritic-perlitic carbon steels and in corundum for Hardox 500 which has tempered martensitic structure

    Preventing Fetal Alcohol Spectrum Disorder in Aboriginal Communities: A Methods Development Project

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    The authors describe their three-year project working collaboratively with Aboriginal communities to prevent fetal alcohol spectrum disorder

    Influence of environment on the corrosion of glass–metal connections

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    'Glass sensors' of the eighteenth century Backer glass and the sixteenth century enamel from Limoges have been chosen for a series of experiments. Combinations of these materials with different base materials such as copper and bronze has been investigated. To create surface changes on the 'glass sensor', a corrosion process was induced in a controlled environment. A variety of corrosive agents such as hydrochloric acid, sulfuric acid, water and formaldehyde were used. The sample immersed in the corrosive solution was exposed alternately to light and high temperature for a total of 38 weeks. During this period, macroscopic and microscopic observations were made and series of tests such as SEM/EDS and Raman spectroscopy were performed on the surface of the samples. ICP-MS methods were used to determine the change in the chemical composition of the solutions where the samples had corroded. The primary aim of this study was to identify the impact of a number of external corrosive variables such as temperature, humidity and local environment to identify the most damaging environments for glass–metal objects. The obtained results showed the chemical and physical phenomena acting on the surface of the glass, metal or in the place of their joints. Information obtained on this study was used to explain the influence of the environment on the surface of glass–metal materials. Results can be used in the design of conservation work as well as for sustainable conservation

    Who's minding the shop? The role of Canadian research ethics boards in the creation and uses of registries and biobanks

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    <p>Abstract</p> <p>Background</p> <p>The amount of research utilizing health information has increased dramatically over the last ten years. Many institutions have extensive biobank holdings collected over a number of years for clinical and teaching purposes, but are uncertain as to the proper circumstances in which to permit research uses of these samples. Research Ethics Boards (REBs) in Canada and elsewhere in the world are grappling with these issues, but lack clear guidance regarding their role in the creation of and access to registries and biobanks.</p> <p>Methods</p> <p>Chairs of 34 REBS and/or REB Administrators affiliated with Faculties of Medicine in Canadian universities were interviewed. Interviews consisted of structured questions dealing with diabetes-related scenarios, with open-ended responses and probing for rationales. The two scenarios involved the development of a diabetes registry using clinical encounter data across several physicians' practices, and the addition of biological samples to the registry to create a biobank.</p> <p>Results</p> <p>There was a wide range of responses given for the questions raised in the scenarios, indicating a lack of clarity about the role of REBs in registries and biobanks. With respect to the creation of a registry, a minority of sites felt that consent was not required for the information to be entered into the registry. Whether patient consent was required for information to be entered into the registry and the duration for which the consent would be operative differed across sites. With respect to the creation of a biobank linked to the registry, a majority of sites viewed biobank information as qualitatively different from other types of personal health information. All respondents agreed that patient consent was needed for blood samples to be placed in the biobank but the duration of consent again varied.</p> <p>Conclusion</p> <p>Participants were more attuned to issues surrounding biobanks as compared to registries and demonstrated a higher level of concern regarding biobanks. As registries and biobanks expand, there is a need for critical analysis of suitable roles for REBs and subsequent guidance on these topics. The authors conclude by recommending REB participation in the creation of registries and biobanks and the eventual drafting of comprehensive legislation.</p

    Urinary EpCAM in urothelial bladder cancer patients: characterisation and evaluation of biomarker potential

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    Background: Epithelial cell adhesion molecule is overexpressed in bladder tumours and released from bladder cancer cells in vitro. We test the hypotheses that urinary EpCAM could act as a biomarker for primary bladder cancer detection and risk stratification. Methods: Epithelial cell adhesion molecule was measured by ELISA in urine from 607 patients with primary bladder tumours and in urine from 53 non-cancer controls. Mann–Whitney tests and ROC analyses were used to determine statistical significance and discrimination between non-cancer controls and different stages and grades of disease. Multivariable modelling and Kaplan–Meier analyses were used to determine prognostic significance. The structure of urinary EpCAM was investigated by western blotting and mass spectrometry. Results: Urinary EpCAM levels increase with stage and grade of bladder cancer. Alongside grade and stage, elevated urinary EpCAM is an independent indicator of poor prognosis with a hazard ratio of 1.76 for bladder cancer-specific mortality. The soluble form of EpCAM in urine is the extracellular domain generated by cleavage between ala243 and gly244. Further studies are required to define the influence of other urinary tract malignancies and benign urological conditions on urinary EpCAM. Conclusion: The extracellular domain of EpCAM is shed into urine by bladder tumours. Urinary EpCAM is a strong indicator of bladder cancer-specific survival, and may be useful within a multi-marker panel for disease detection or as a stand-alone marker to prioritise the investigation and treatment of patients. The mechanisms and effects of EpCAM cleavage in bladder cancer are worthy of further investigation, and may identify novel therapeutic targets

    Combined Tumor Cell-Based Vaccination and Interleukin-12 Gene Therapy Polarizes the Tumor Microenvironment in Mice

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    Tumor progression depends on tumor milieu, which influences neovasculature formation and immunosuppression. Combining immunotherapy with antiangiogenic/antivascular therapy might be an effective therapeutic approach. The aim of our study was to elaborate an anticancer therapeutic strategy based on the induction of immune response which leads to polarization of tumor milieu. To achieve this, we developed a tumor cell-based vaccine. CAMEL peptide was used as a B16-F10 cell death-inducing agent. The lysates were used as a vaccine to immunize mice bearing B16-F10 melanoma tumors. To further improve the therapeutic effect of the vaccine, we combined it with interleukin (IL)-12 gene therapy. IL-12, a cytokine with antiangiogenic properties, activates nonspecific and specific immune responses. We observed that combined therapy is significantly more effective (as compared with monotherapies) in inhibiting tumor growth. Furthermore, the tested combination polarizes the tumor microenvironment, which results in a switch from a proangiogenic/immunosuppressive to an antiangiogenic/immunostimulatory one. The switch manifests itself as a decreased number of tumor blood vessels, increased levels of tumor-infiltrating CD4+, CD8+ and NK cells, as well as lower level of suppressor lymphocytes (Treg). Our results suggest that polarizing tumor milieu by such combined therapy does inhibit tumor growth and seems to be a promising therapeutic strategy

    Corrosion challenges towards a sustainable society

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    A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate-resilient energy systems and infrastructures brings with it a long-term direction, so as a result the long-term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind "Corrosion Challenges Towards a Sustainable Society" presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics
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