10 research outputs found

    Liquid-phase sintering of medical-grade P558 stainless steel using a new biocompatible eutectic additive

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    Cataloged from PDF version of article.One of the effective approaches to reduce residual pores in powder metallurgy parts is activated liquidphase sintering process using proper additives. In this work, for the first time, a new biocompatible additive (Mn–11.5 wt.% Si, a eutectic alloy) is experimented for liquid-phase sintering of nanocrystalline/amorphous P558 stainless steel powders. It is realized that by increasing the sintering aid content and temperature, the density is effectively increased: a sharp densification progress when the sintering temperature increases from 1000 °C to 1050 °C and a slower densification rate when it exceeds 1050 °C. This preliminary study opens up the development of high-density medical-grade stainless steels produced by powder metallurgy, where suitable additives can lower sintering temperature and time, which is promising for retarding grain growth and commercial applications. © 2012 Elsevier B.V. All rights reserve

    Microstructural characterization of medical-grade stainless steel powders prepared by mechanical alloying and subsequent annealing

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    Cataloged from PDF version of article.The harmful effect of nickel ions released from conventional stainless steel implants has provided a high level of motivation for the further development of nickel-free stainless steels. In this paper, the microstructure of medical-grade nickel-free stainless steel powders, with the chemical composition of ASTM F2581, is studied during mechanical alloying and subsequent annealing. Rietveld X-ray diffraction and transmission electron microscopy evaluations reflect nanocrystallization, austenitization and amorphization of the powders due to mechanical activation. It is also realized that annealing of the as-milled powder can develop a single austenitic structure with nanometric crystallite sizes, implying a considerable inherent resistance to grain growth. This study demonstrates the merit of mechanical alloying and subsequent annealing in the development of nanostructured medical-grade stainless steels. (C) 2012 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserve

    Educational Needs of Nurses in Intensive Care Unit for Poisoned Patients

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    Objectives: Poisoned patients are at risk of impaired ventilation in many situations. The purpose of this descriptive study was to investigate the impact of educational workshops on nurses' knowledge, confidence, and attitude in taking care of poisoned patients. Materials and Methods: This descriptive study was performed on 60 nursing staff in the intensive care unit (ICU) for poisoned patients in Imam Reza (p) hospital, Mashhad, Iran. Data was gathered by a researcher-designed questionnaire. Studied scales included perceived importance and novelty of educational meeting, matching with professional and educational needs, illustration of practical and knowledge weaknesses and strength and finally satisfaction in holding regular workshops annually. Two, half day workshops were held and various items were taught with various methods. The knowledge of participants was assessed by pretests and post-tests consisting of 12 items related to workshop topics. The impact of these educational meetings was evaluated and the results were analyzed by the SPSS software. Results: According to the results, workshops improved awareness of nurses about their weakness and strength points, professional knowledge and their interest and attention; likewise all participants had the same opinion about a strong need to hold similar workshops more than once and preferably 2 to 3 times annually. Conclusion: It seems that short educational courses in small groups for reviewing the old data and recent findings in the context of critical care are useful in order to promote the knowledge and skills of ICU staff in taking care of poisoned patient

    Functional foods as source of bioactive principles. Some marked examples

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    Functional foods are those that have a beneficial effect on health beyond the basic function of nutrition, helping to promote better health conditions and to reduce the risk of various diseases. This concept was created in Japan in the 1980s and is widely used around the world. The regulation of these products is made by different authorities and has not been defined yet in many countries. The field of food production has increased and changed considerably in the last decades, since the consumers believe that foods, besides satisfy hunger and to provide necessary nutrients for humans, also contribute directly to improve their health conditions. The present chapter will focus with marked examples the main categories of functional foods and respective therapeutic potential (cardioprotective, hepatoprotective, hypolipidemic, antioxidant, anticancer, anti-inflammatory properties, etc.) as well as the active principles responsible for the medicinal properties (flavonoids, alkaloids, terpenes, etc.), including curcuma, garlic, olive oil, grape, broccoli, and probiotic, among others

    Metal-based Lewis acid catalysts for conversion of a variety of aldehydes with acetic anhydride to gem 1,1-diacetates

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