7,708 research outputs found
Deposition in supercritical fluids: from silver to semiconductors
No full textThere is great interest in developing new routes to novel functional materials, particularly for heterogeneous nanocomposites of metals or semiconductors with polymeric hosts. Supercritical fluids have become important media for the synthesis of such nanocomposites largely because of their unique properties, but also through their perceived environmental benefits over conventional routes. In this feature article, we focus on the deposition of silver and semiconductor nanoparticles into polymer substrates by use of supercritical fluids. These processes develop nanocomposites with distinct characteristics for optical and biomedical applications. The preparation and characterisation of silver and semiconductor nanoparticles is described and a brief discussion is also extended to some other novel deposition systems in supercritical fluids
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Microscopic spacial effect on the dispersion polymerization in scCO2
No full textWe report for the first time the microscopic spacial effect on the dispersion polymerization of methyl methacrylate (MMA) in supercritical carbon dioxide (scCO2). A variety of different-sized high-pressure vessels including microstructured holey optical fiber were employed to conduct the polymerization reactions. The molecular weights of the polymer products indicate that the function of the stabilizer and the process of chain growth are not significantly influenced. However, the SEM images show a gradual loss of the controlled morphology for the polymer products in reactors of dimension less than 1 mm under the same reaction conditions. This study provides a better understanding of the mechanism of the dispersion polymerization progress and gives a very important caution on the performance of microreactors.Short communication. Polymerization in supercritical CO2 is investigated, including unusual microfluidic reactors such as microstructured optical fibres. In microreactors of critical dimension <1 mm polymer chain growth is unchanged; however the morphology of the polymer is heavily modified. This provides an important caution on the performance of microreactors as a function of size.<br/
The scale-up of a tissue engineered porous hydroxyapatite polymer composite scaffold for use in bone repair: an ovine femoral condyle defect study
No full textThe development of an osteogenic bone graft substitute has important practical and cost implications in many branches of medicine where bone regeneration is required. Previous in vitro and small animal (murine) in vivo studies highlighted a porous hydroxyapatite/poly (dl‐lactic acid) composite scaffold in combination with skeletal stem cells (SSCs) as a potential bone graft substitute candidate. The aim of the current study was to scale up the bone cell‐scaffold construct to large animals and examine the potential for repair of a critical‐sized defect via an ovine model. SSC seeded scaffolds (and unseeded scaffold controls) were implanted bilaterally into ovine femoral condyle critical defects for 3 months. A parallel in vitro analysis of ovine SSC seeded scaffolds was also performed. Post mortem mechanical indentation testing showed the bone strengths of the defect sites were 20% (controls) and 11% (SSC seeded scaffolds) those of normal cancellous bone (p < 0.01). MicroCT analysis demonstrated new bone formation within all defects with a mean increase of 13.4% in the control scaffolds over the SSC seeded scaffolds (p = 0.14). Histological examination confirmed these findings, with enhanced quality new bone within the control defects. This study highlights important issues and steps to overcome in scale‐up and translation of tissue engineered products. The scaffold demonstrated encouraging results as an osteoconductive matrix; however, further work is required with cellular protocols before any human trials
Steven Bialer and Patti Smith, July 1978
No full textMusician, poet, and author Patti Smith sits on a bed in a hotel room in July 1978. The photograph was taken by Don Hamerman as part of a session for "Unicorn Times," an alternative performing arts periodical in Washington, D.C. Steven Bialer, the Design Director for "Unicorn Times," is seated on the bed next to Smith
Steven Garber
No full textSteven Garber speaks on the importance and value of truth.
Steven Garber is the principal of The Washington Institute for Faith, Vocation & Culture, which is focused on reframing the way people understand life, especially the meaning of vocation and the common good. A consultant to foundations, corporations and educational institutions, he is a teacher of many people in many places. The author of The Fabric of Faithfulness: Weaving Together Belief and Behavior, and Visions of Vocation: Common Grace for the Common Good, he is also a contributor to the books, Faith Goes to Work: Reflections from the Marketplace, and Get Up Off Your Knees: Preaching the U2 Catalogue. He lives with his wife Meg in Virginia
Steven Yedinak Interview
No full textLTC (RET) Steven M. Yedinak commissioned in the U. S. Army Infantry in 1963 and subsequently spent 26 years in Special Forces and Airborne Infantry. He served two combat tours in Vietnam (1966-67 & 1971-1972), and started the Mobile Guerrilla Force. He is the author of Hard to Forget: An American with the Mobile Guerrilla Force in Vietnam (Random House, 1998). He retired from the Army in 1989
Gamification is broken. An interview with Steven Poole
No full textSteven Poole is the author of Trigger Happy (2000. New York, NY: Arcade Publish), Unspeak (2006. New York, NY: Grove Press), and You Aren’t What You Eat (2012. In press). He has written extensively on books, culture, and videogames for The Guardian and other publications
Steven Pinker on language and thought
No full textEducação Superior::Linguística, Letras e Artes::LinguísticaThis video presents an exclusive preview of Steven Pinker's book: the stuff of thought. The author looks at language and how it expresses what goes on in our minds and how the words we choose communicate much more than we realize. For Steven Pinker, the brilliance of the mind lies in the way it uses just two processes to turn the finite building blocks of our language into infinite meanings. The first is metaphor: we take a concrete idea and use it as a stand-in for abstract thoughts. The second is combination: we combine ideas according to rules, like the syntactic rules of language, to create new thoughts out of old one
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