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In situ characterization of Ti-peroxy gel during formation on titanium surfaces in hydrogen peroxide containing solutions

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materials science and engineering C 2006年第8期26卷 1408-1411页

作者： Muyco, Julie J. Gray, Jeremy J. Ratto, Timothy V. Orme, Christine A. McKittrick, Joanna Frangos, John Lawrence Livermore National Laboratory Chemistry and Materials Science 7000 East Ave. L-350 Livermore CA 94550 United States University of California Mechanical and Aerospace Engineering Materials Science and Engineering Graduate Program 9500 Gilman Dr La Jolla CA 92093 United States La Jolla Bioengineering Institute 505 Coast Blvd. S. Ste. #405 La Jolla CA 92037 United States

Three possible functions of Ti-peroxy gel are: reduction of the inflammatory response through the reduction of hydrogen peroxide and other reactive oxygen species;creation of a favorable surface for calcium phosphate nucleation;and as a transitional layer between the compliant surrounding tissue and the stiff titanium. Traditional surface characterization techniques operate in high vacuum environments that alter the actual sample-solution interface. Our studies used techniques that allowed samples to remain in solution and be observed over time. Atomic force microscopy (AFM) force-distance curves, electrochemical impedance spectroscopy (EIS), and Raman spectroscopy were each used in situ to define kinetic and mechanical properties of Ti-peroxy gel as it formed over time on titanium during exposure to hydrogen peroxide. Our studies enabled us to monitor real-time changes in the native oxide layer on titanium in hydrogen peroxide containing solution, including the formation of a Ti-peroxy gel layer above the native oxide. Peaks attributed to Ti-peroxy gel were seen to emerge over the course of several hours using in situ Raman spectroscopy. Force-distance curves suggest a layer that thickens with time on the titanium sample surface. EIS data showed that changes in the surface layers could be monitored in solution over time. © 2005 Elsevier B.V. All rights reserved.

关键词： Gels

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Chitosan for biofunctionalization of microsystems

Chitosan for biofunctionalization of microsystems

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2006 IEEE/NLM Life science Systems and Applications Workshop, LiSA 2006

作者： Koev, Stephan T. Powers, Michael A. Badilita, Vlad Yi, Hyunmin Bentley, William E. Payne, Gregory F. Rubloff, Gary W. Ghodssi, Reza Department of Electrical and Computer Engineering University of Maryland College Park MD 20742 Department of Materials Science and Engineering University of Maryland College Park MD 20742 Department of Chemical Engineering University of Maryland College Park MD 20742 University of Maryland College Park MD 20742 University of Maryland College Park MD 20742 Bioengineering Graduate Program University of Maryland College Park MD 20742

ISBN: (纸本)1424402786

We present the use of the polysaccharide chitosan for immobilizing biomolecules on microfabricated device surfaces. The main advantages of chitosan are its abundance of primary amine groups and its ability to be electrodeposited. Biomolecules are easily attached to chitosan's amines by standard glutaraldehyde chemistry. The electrodeposition of chitosan allows accurate spatial and temporal control of biomolecule placement. We have demonstrated this biofunctionalization method for two different BioMEMS devices: a biophotonic sensor and a micromechanical biosensor. We have successfully assembled probe DNA on each of them and detected hybridization with target DNA as a demonstration of sensor operation. Here, we briefly present the fabrication procedure and testing results for both of these BioMEMS sensing devices. © 2006 IEEE.

关键词： Microsystems

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Ottenimento di silice amorfa a partire da pula di riso madiante estrazione

C e Ca

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C e Ca 2006年第2期36卷 141-145页

作者： Junkes, J.A. Della, V.P. Acchar, W. Oliveira, A.P.N. Hotza, D. Materials Science and Engineering Graduate Program Federal University of Santa Catarina Florianopolis Brazil Department of Physics Federal University of Rio Grande do Norte Natal Brazil Department of Chemical Engineering Federal University of Santa Catarina Florianopolis Brazil

Rice husk can be an interesting source of raw material for obtaining silica, due to its composition, availability and cost. The extraction process of silica from rice husk can be divided in two parts. First some components of rice husk are removed by acid leaching, using HCl, H2SO4, or a mixture of them, followed by calcination for burning out carbon compounds. The residue obtained after calcination is composed of about 95% amorphous silica. In this work, silica was produced from rice husk following the steps previously described, using leaching solutions of 10% HCl, 10% H 2SO4 and a mixture of 10% HCl and 10% H2SO 4. Calcination of leached materials was carried out at 600 or 700°C for 3 h. The silica powder obtained presented a mean particle size of 18 μm, around 98% amorphous SiO2 with a specific surface area of about 300 m2/g.

关键词： Hulls (seed coverings)

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SiO2-coated porous anodic alumina membrane for electroosmotic pumping

SiO2-coated porous anodic alumina membrane for electroosmoti...

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2006 ASME International Mechanical engineering Congress and Exposition, IMECE2006

作者： Vajandar, Saumitra K. Xu, Dongyan Li, Deyu Markov, Dmitry Wikswo, John Hofmeister, William Interdisciplinary Graduate Program in Materials Science Vanderbilt University Nashville TN 37235 United States Department of Mechanical Engineering Vanderbilt University Nashville TN 37235 United States Department of Physics and Astronomy Vanderbilt University Nashville TN 37235 United States Center for Laser Applications University of Tennessee Space Institute Tullahoma TN 37388 United States

ISBN: (纸本)0791837904

Electroosmotic pumping has been extensively used in biomedical lab-on-a-chip devices and micropumps for critical applications such as microelectronic cooling. In many applications, a high flow rate is a key requirement in desired performance so constant efforts have been made to increase the pumping flow rate through unit area to achieve the compact design. We report here an attempt of using SiO2-coated anodic porous alumina membrane as the material to achieve high electroosmotic pumping flow rate. High quality porous alumina membranes of controllable pore diameter in the range of 20-300 nm and pore length of 60-100 μm have been fabricated with electrochemical anodization. The pores are uniform and hexagonally packed with a high porosity of up to 50% and a tortuosity of a bare minimum of unity. In addition, the inner surface of the pores could be conformally coated with a thin layer (∼ 5 nm) of SiO2 with sol-gel chemistry to achieve a high zeta potential. Scanning electron microscopy of the cross section of the membrane verified these facts. Electroosmotic pumping performance of these membranes has been investigated using standard relevant aqueous electrolyte buffer solutions and results showed that SiO2-coated porous alumina could achieve a higher flow rate compared with other microporous materials such as glass frit and porous silicon reported in the literature. Copyright © 2006 by ASME.

关键词： Membranes

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Identifying dead regions in the cochlea through the TEN Test

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Brazilian Journal of Otorhinolaryngology 2006年第5期72卷 673-682页

作者： Jacob, Regina T.S. Fernandes, João Cândido Manfrinato, Jair Iório, Maria Cecília M. Doctor on Rehabilitation Science/Human Communication Disorders at the Sao Paulo University Craniofacial Anomalies Rehabilitation Hospital/Bauru Campus (HRAC/USP/Bauru) Speech Therapist of the CEDALVI/HRAC/USP Bauru. Lecturer at UNESP/Bauru Professor of the post-graduate program on Rehabilitation Science/Human Communication Disorders at HRAC/USP/Bauru. Doctor on Agricultural Science at UNESP/Botucatu Head of the Production Engineering Department at UNESP/Bauru. Doctor on Human Communication Disorders at the UNIFESP/EPM Adjunct Professor of the Speech Therapy Course at UNIFESP/EPM. Sao Paulo University Craniofacial Anomalies Rehabilitation Hospital/Bauru Campus.

An audiogram is not sufficient to indicate cochlear dead regions. Aim: To investigate cochlear dead regions in sensorineural hearing loss subjects using the TEN test. Site: CEDALVI/ HRAC-USP-Bauru/Sao Paulo/Brazil, August 2003 to February 2004. Study Design: A contemporary cross-sectional cohort study. Material and Methods: The TEN test was applied in three groups: G1(5 women with pure-tone thresholds within normal limits);G2(4 women and 5 men with moderate sensorineural flat hearing loss);G3(19 women and 24 men with mild to severe sloping sensorineural hearing loss). Results: In the G1 group the TEN value required to eliminate the test tone was, on average, close to the absolute threshold for all frequencies. No dead regions were found in the ears tested in group G2. 76 ears were tested in group G3, and six showed no evidence of dead regions in the cochlea. Conclusions:The TEN test was an effective test to indicate a dead region in the cochlea of subjects with sloping sensorineural hearing loss. There is evidence that pure-tone detection is different for subjects with high frequency sensorineural hearing loss and flat hearing loss;we observed a significant difference between the masked threshold and the absolute threshold only in sloping hearing loss and not for flat hearing loss. All Rights reserved 1933 / 2006 © Revista Brasileira de Otorrinolaringologia.

关键词： Cochlea Dead cochlear regions Hearing aids Hearing loss

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Transforming K-12 education via the collaborative large-scale engineering analysis network for environmental research (CLEANER) project

Transforming K-12 education via the collaborative large-scal...

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113th Annual ASEE Conference and Exposition, 2006

作者： Eschenbach, Elizabeth Johnson, James H. Brus, Chris Carlson, Patricia Giammar, Dan Grauer, Bette Hotaling, Liesl Oguntimein, Gbekeloluwa Safferman, Steven Wentling, Tim Humboldt State University United States Department of Environmental Resources Engineering Humboldt State University United States Howard University United States Department of Environmental Engineering College of Engineering Architecture and Computer Sciences Howard University United States Board of Scientific Counselors Executive Committee U.S. Environmental Protection Agency Office of Research and Development United States EPA's Science Advisory Board Department of Energy-sponsored HBCU/MI Environmental Technology Consortium Board Environmental Studies and Toxicology and the Engineering Council of the American Society for Engineering Education United States University of Iowa United States Program University of Iowa United States Rose-Hulman Institute of Technology United States Department of Rhetoric Rose-Hulman Institute ot Technology U.S. Air Forcer United States Army's Aberdeen Proving Ground NASA's Classroom of the Future Wheeling WV United States Washington University United States Department of Civil Engineering Washington University St. Louis United States Environmental Engineering Science Program Center for Materials Innovation United States McPherson High School United States McPherson High School McPherson KS United States Stevens Institute of Technology United States Stevens Institute of Technology United States Morgan State University United States Michigan State University United States Biosystems and Agricultural Engineering Department Michigan State University United States University of Dayton United States U.S. EPA Office of Research and Development United States National Center for Supercomputing Applications United States Department of Information Science Graduate School of Library and Information Science National Center for Supercomputing Applications University of Illinois United States

The Collaborative Large-scale engineering Analysis Network for Environmental Research (CLEANER) Project Office has been established with funding from the National science Foundation (NSF) to the University of Illinois Urbana-Champaign (UIUC) and a coalition of 11 other institutions. The project office is coordinating the creation of a strategic plan consisting of research, cyberinfrastructure, and education plans that set forth a roadmap for the collaborative engineering analysis network for the study of environmental problems. This report will be completed by July 2007 and requires input from K-12 educators, administrators and other stakeholders in K-12 education. This paper describes the CLEANER project, provides an example of the CLEANER Education Committee's vision for the K-12 area and lists contacts for further information. The intention of this paper is to elicit input from the K-12 engineering education community, including K-12 educators, on how the CLEANER Education Plan could better meet the future needs of K-12 students and educators © American Society for engineering Education, 2006.

关键词： engineering education

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Chitosan for Biofunctionalization of Microsystems

Chitosan for Biofunctionalization of Microsystems

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IEEE/NLM Life science Systems and Applications Workshop

作者： Stephan T. Koev Michael A. Powers Vlad Badilita Hyunmin Yi William E. Bentley Gregory F. Payne Gary W. Rubloff Reza Ghodssi Institute for Systems Research ISR University of Maryland College Park MD USA University System of Maryland Adelphi MD US Department of Materials Science and Engineering University of Maryland College Park MD USA Department of Chemical Engineering University of Maryland College Park MD 20742 University of Maryland Biotechnology Institute (UMBI) University of Maryland College Park MD 20742 Bioengineering Graduate Program University of Maryland College Park MD 20742 University of Maryland College Park MD USA University of Maryland Biotechnology Institute College Park MD USA Institute for Systems Research (ISR) University of Maryland College Park MD 20742 Department of Materials Science and Engineering University of Maryland College Park MD 20742 Department of Electrical and Computer Engineering University of Maryland College Park MD 20742 Institute for Systems Research (ISR) University of Maryland College Park MD 20742

ISBN: (纸本)1424402778

We present the use of the polysaccharide chitosan for immobilizing biomolecules on microfabricated device surfaces. The main advantages of chitosan are its abundance of primary amine groups and its ability to be electrodeposited. Biomolecules are easily attached to chitosan 's amines by standard glutaraldehyde chemistry. The electrodeposition of chitosan allows accurate spatial and temporal control of biomolecule placement. We have demonstrated this biofunctionalization method for two different bioMEMS devices: a biophotonic sensor and a micromechanical biosensor. We have successfully assembled probe DNA on each of them and detected hybridization with target DNA as a demonstration of sensor operation. Here, we briefly present the fabrication procedure and testing results for both of these bioMEMS sensing devices

关键词： DNA Biosensors Molecular biophysics Probes Micromechanical devices Optical sensors Optical surface waves Optical interferometry Assembly Biomedical optical imaging

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PEG/protein co-immobilized gold colloids

PEG/protein co-immobilized gold colloids

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54th SPSJ Symposium on Macromolecules

作者： Nagasaki, Yukio Yoshinaga, Kenji Ishii, Takehiko Iijima, Michihiro Aboshi, Fumiko Sakura, Takeshi Takahashi, Tadahito Kataoka, Kazunori Tsukuba Research Center for Interdisciplinary Materials Science University of Tsukuba 1-1-1 Tenn-noudai Tsukuba Ibaraki 305-8573 Japan Department of Materials Science Tokyo University of Science Oyama National College of Technology Preventure Program JST Department of Materials Science and Engineering Graduate School of Engineering University of Tokyo

Gold colloid possessing both lipase and PEG tethered chains on the surface was prepared by the adsorption of lipase, followed by the immobilization of the PEG/polycation block copolymer on the colloid surface. The obtained colloid showed a high dispersion stability at a high salt concentration. The enzymatic activity of the lipase on the colloid complex retained intact. Surprisingly, more than 95% of the initial enzymatic activity was retained after repeated thermal treatments (5 times) at 58°C for 10 min. The PEG condensed layer between the immobilized enzyme on the gold colloid may prevent the denaturation of the enzyme at high temperature.

关键词： Colloids

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Nanocrystalline material in toroidal cores for current transformer: Analytical study and computational simulations

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materials Research 2005年第4期8卷 395-400页

作者： Luciano, Benedito Antonio Cavalcante de Albuquerque, João Marcelo Benício de Castro, Walman Moreira Afonso, Conrado Ramos Department of Electrical Engineering CEEI/UFCG P.B. 10105 58109 970 Campina Grande - PB Brazil Department of Mechanical Engineering CCT/UFCG P.B. 10105 58109-970 Campina Grande - PB Brazil Department of Materials Engineering Pos-Graduate Program in Materials Science Engineering UFSCar Via Washington Luís km 235 13565-905 São Carlos - SP Brazil

Based on electrical and magnetic properties, such as saturation magnetization, initial permeability, and coercivity, in this work are presented some considerations about the possibilities of applications of nanocrystalline alloys in toroidal cores for current transformers. It is discussed how the magnetic characteristics of the core material affect the performance of the current transformer. From the magnetic characterization and the computational simulations, using the finite element method (FEM), it has been verified that, at the typical CT operation value of flux density, the nanocrystalline alloys properties reinforce the hypothesis that the use of these materials in measurement CT cores can reduce the ratio and phase errors and can also improve its accuracy class. © 2005.

关键词： Steel

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Developing an atomic-level understanding of the mechanisms that govern CO2 sequestration mineral carbonation reaction processes

Developing an atomic-level understanding of the mechanisms t...

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2005 TMS Annual Meeting

作者： McKelvy, Michael J. Chizmeshya, Andrew V. G. Diefenbacher, Jason Béarat, Hamdallah Carpenter, R.W. Wolf, George Gormley, Deirdre Center for Solid State Science Arizona State University Tempe AZ 85287 United States Science and Engineering of Materials Graduate Program Arizona State University Tempe AZ 85287 United States Department of Chemistry and Biochemistry Arizona State University Tempe AZ 85287 United States

Mineral carbonation is an emerging CO2 sequestration candidate technology, which produces environmentally benign and geologically stable materials. The primary challenge is economically viable process development. Serpentine and olivine minerals are candidate feedstock materials of interest, due to their wide availability, low-cost, and rapid mineral carbonation potential. Cost-effectively enhancing their carbonation reactivity is critical to reducing mineral sequestration process cost. We will discuss our recent research into the mechanisms that govern serpentine and olivine mineral carbonation reaction processes, including in situ observations of the mineral carbonation process and a novel mechanistic approach to enhance carbonation reactivity that avoids the cost of mineral activation. Our goal is to develop the necessary atomic-level understanding to engineer improved carbonation materials and processes to reduce process cost.

关键词： Chemical reactions

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