WorldWideScience

Sample records for characterization engineering status

  1. Status of the Combined Cycle Engine Rig

    Science.gov (United States)

    Saunders, Dave; Slater, John; Dippold, Vance

    2009-01-01

    Status for the past year is provided of the turbine-based Combined-Cycle Engine (CCE) Rig for the hypersonic project. As part of the first stage propulsion of a two-stage-to-orbit vehicle concept, this engine rig is designed with a common inlet that supplies flow to a turbine engine and a dual-mode ramjet / scramjet engine in an over/under configuration. At Mach 4 the inlet has variable geometry to switch the airflow from the turbine to the ramjet / scramjet engine. This process is known as inlet mode-transition. In addition to investigating inlet aspects of mode transition, the rig will allow testing of turbine and scramjet systems later in the test series. Fully closing the splitter cowl "cocoons" the turbine engine and increases airflow to the scramjet duct. The CCE Rig will be a testbed to investigate integrated propulsion system and controls technology objectives. Four phases of testing are planned to 1) characterize the dual inlet database, 2) collect inlet dynamics using system identification techniques, 3) implement an inlet control to demonstrate mode-transition scenarios and 4) demonstrate integrated inlet/turbine engine operation through mode-transition. Status of the test planning and preparation activities is summarized with background on the inlet design and small-scale testing, analytical CFD predictions and some details of the large-scale hardware. The final stages of fabrication are underway.

  2. Vortex Characterization for Engineering Applications

    Energy Technology Data Exchange (ETDEWEB)

    Jankun-Kelly, M; Thompson, D S; Jiang, M; Shannahan, B; Machiraju, R

    2008-01-30

    Realistic engineering simulation data often have features that are not optimally resolved due to practical limitations on mesh resolution. To be useful to application engineers, vortex characterization techniques must be sufficiently robust to handle realistic data with complex vortex topologies. In this paper, we present enhancements to the vortex topology identification component of an existing vortex characterization algorithm. The modified techniques are demonstrated by application to three realistic data sets that illustrate the strengths and weaknesses of our approach.

  3. US nuclear engineering education: Status and prospects

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This study, conducted under the auspices of the Energy Engineering Board of the National Research Council, examines the status of and outlook for nuclear engineering education in the United States. The study resulted from a widely felt concern about the downward trends in student enrollments in nuclear engineering, in both graduate and undergraduate programs. Concerns have also been expressed about the declining number of US university nuclear engineering departments and programs, the aging of their faculties, the appropriateness of their curricula and research funding for industry and government needs, the availability of scholarships and research funding, and the increasing ratio of foreign to US graduate students. A fundamental issue is whether the supply of nuclear engineering graduates will be adequate for the future. Although such issues are more general, pertaining to all areas of US science and engineering education, they are especially acute for nuclear engineering education. 30 refs., 12 figs., 20 tabs.

  4. Light-duty diesel engine development status and engine needs

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

    This report reviews, assesses, and summarizes the research and development status of diesel engine technology applicable to light-duty vehicles. In addition, it identifies specific basic and applied research and development needs in light-duty diesel technology and related health areas where initial or increased participation by the US Government would be desirable. The material presented in this report updates information provided in the first diesel engine status report prepared by the Aerospace Corporation for the Department of Energy in September, 1978.

  5. Status of Research in Biomedical Engineering 1968.

    Science.gov (United States)

    National Inst. of General Medical Sciences (NIH), Bethesda, MD.

    This status report is divided into eight sections. The first four represent the classical engineering or building aspects of bioengineering and deal with biomedical instrumentation, prosthetics, man-machine systems and computer and information systems. The next three sections are related to the scientific, intellectual and academic influence of…

  6. Biomedical engineering education--status and perspectives.

    Science.gov (United States)

    Magjarevic, Ratko; Zequera Diaz, Martha L

    2014-01-01

    Biomedical Engineering programs are present at a large number of universities all over the world with an increasing trend. New generations of biomedical engineers have to face the challenges of health care systems round the world which need a large number of professionals not only to support the present technology in the health care system but to develop new devices and services. Health care stakeholders would like to have innovative solutions directed towards solving problems of the world growing incidence of chronic disease and ageing population. These new solutions have to meet the requirements for continuous monitoring, support or care outside clinical settlements. Presence of these needs can be tracked through data from the Labor Organization in the U.S. showing that biomedical engineering jobs have the largest growth at the engineering labor market with expected 72% growth rate in the period from 2008-2018. In European Union the number of patents (i.e. innovation) is the highest in the category of biomedical technology. Biomedical engineering curricula have to adopt to the new needs and for expectations of the future. In this paper we want to give an overview of engineering professions in related to engineering in medicine and biology and the current status of BME education in some regions, as a base for further discussions.

  7. ISTAR: Project Status and Ground Test Engine Design

    Science.gov (United States)

    Quinn, Jason Eugene

    2003-01-01

    Review of the current technical and programmatic status of the Integrated System Test of an Airbreathing Rocket (ISTAR) project. November 2002 completed Phase 1 of this project: which worked the conceptual design of the X-43B demonstrator vehicle and Flight Test Engine (FTE) order to develop realistic requirements for the Ground Test Engine (GTE). The latest conceptual FTE and X-43B configuration is briefly reviewed. The project plan is to reduce risk to the GTE and FTE concepts through several tests: thruster, fuel endothermic characterization, engine structure/heat exchanger, injection characterization rig, and full scale direct connect combustion rig. Each of these will be discussed along with the project schedule. This discussion is limited due to ITAR restrictions on open literature papers.

  8. The present status of software engineering

    CERN Document Server

    Pressman, Roger S

    1991-01-01

    In this seminar, we will discuss the present status and future directions of software engeneering and CASE. Key topics to be discussed include: new paradigms for software engineering; software metrics; process assessment; the current state of analysis and design methods; reusability and re-engineering; formal methods. Among the questions to be answered are: How will software engineering change as the 1990s progress? What are the "technology drivers"? What will analysis, design, coding, testing, quality assurance and software management look like in the year 2000? How will CASE tools evolve in the 1990s and will they be as "integrated" as many people believe? How can you position your Organization to accommodate the coming changes?

  9. Current Status of the KSTAR Engineering

    Institute of Scientific and Technical Information of China (English)

    J. S. Bak; K. Kim; C. H. Choi; Y. K. Oh; B. C. Kim; N. I. Her; H. L. Yang; G. S. Lee; the KSTAR Team

    2004-01-01

    As there is substantial progress in the KSTAR tokamak engineering, all the major structures and sub-systems are under fabrication and in procurement phase. The vacuum vessel,port, cryostat cylinder, lid, and bellows are being rigorously fabricated in the factory. The lower part of the KSTAR such as cryostat base and gravity support has been almost finished in its fabrication. There are also great progresses and significant results in manufacturing of the superconducting magnet, including four Toroidal Field (TF) coils, lower and upper PF7 coils which are the largest Poloidal Field (PF) coils. The TF00 coil, which has been made for test and back-up of the TF magnet system, was successfully tested in the cool-down and current charging. As the fabrications and procurements of major structures have been actively proceeded, assembly works were also launched from Aug. 2003. More detailed description on these status, results, and plans will be described in this paper.

  10. Microbial alcohol dehydrogenases: identification, characterization and engineering

    NARCIS (Netherlands)

    Machielsen, M.P.

    2007-01-01

    Keywords: alcohol dehydrogenase, laboratory evolution, rational protein engineering, Pyrococcus furiosus, biocatalysis, characterization, computational design, thermostability.   Alcohol dehydrogeases (ADHs) catalyze the interconversion of alcohols, aldehydes and ketones. They display a wide variety

  11. Wind Energy Status and Future Wind Engineering Challenges: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Thresher, R.; Schreck, S.; Robinson, M.; Veers, P.

    2008-08-01

    This paper describes the current status of wind energy technology, the potential for future wind energy development and the science and engineering challenges that must be overcome for the technology to meet its potential.

  12. Electrical Characterization of Engineering Materials

    OpenAIRE

    Mohammad A. Alim

    1996-01-01

    Engineering material systems for smart components and novel device applications require a thorough understanding on the structure-property-processing relationships to optimize their performance. The factors determining performance characteristics of the multi-phase/component heterogeneous polycrystalline hybrid (MPCHPH) systems are not identical to devices based on single-crystal/single-junction (SCSJ) technology. Performing SCSJ-like data-analysis on the MPCHPH systems can lead to confusion ...

  13. Current status of duplex surface engineered Ti-based materials

    Institute of Scientific and Technical Information of China (English)

    T.Bell

    2004-01-01

    Industrial exploitation of the high specific strength and corrosion resistance of titanium were dominated historically by the technological advances which have been made in gas-turbine engine and aircraft components. Realization of the possible benefits in general engineering has been limited by the absence of any proven and reliable means of overcoming the poor wear resistance and galling tendency suffered by titanium alloys when in contact with other materials. This problem can only be addressed by optimizing and demonstrating industrially viable surface engineering processes for titanium in general engineering. The status of single and duplex surface engineering systems are reviewed. In addition, in order to fully realize the potential of advanced surface engineering of titanium components contact mechanics models are developed to enable the automotive engineers to design dynamically the loaded automotive engine and transmission components.

  14. Status on the Verification of Combustion Stability for the J-2X Engine Thrust Chamber Assembly

    Science.gov (United States)

    Casiano, Matthew; Hinerman, Tim; Kenny, R. Jeremy; Hulka, Jim; Barnett, Greg; Dodd, Fred; Martin, Tom

    2013-01-01

    Development is underway of the J -2X engine, a liquid oxygen/liquid hydrogen rocket engine for use on the Space Launch System. The Engine E10001 began hot fire testing in June 2011 and testing will continue with subsequent engines. The J -2X engine main combustion chamber contains both acoustic cavities and baffles. These stability aids are intended to dampen the acoustics in the main combustion chamber. Verification of the engine thrust chamber stability is determined primarily by examining experimental data using a dynamic stability rating technique; however, additional requirements were included to guard against any spontaneous instability or rough combustion. Startup and shutdown chug oscillations are also characterized for this engine. This paper details the stability requirements and verification including low and high frequency dynamics, a discussion on sensor selection and sensor port dynamics, and the process developed to assess combustion stability. A status on the stability results is also provided and discussed.

  15. Electrical Characterization of Engineering Materials

    Directory of Open Access Journals (Sweden)

    Mohammad A. Alim

    1996-01-01

    Full Text Available Engineering material systems for smart components and novel device applications require a thorough understanding on the structure-property-processing relationships to optimize their performance. The factors determining performance characteristics of the multi-phase/component heterogeneous polycrystalline hybrid (MPCHPH systems are not identical to devices based on single-crystal/single-junction (SCSJ technology. Performing SCSJ-like data-analysis on the MPCHPH systems can lead to confusion in delineating simultaneously operative phenomena when “physical geometrical factors”are used in normalizing the as-measured electrical parameters or electrical quantities. Such an analytical approach can vitiate interpretation when microstructural inhomogeneity plays a key role in determining the electrical path. The advantage of using the as-measured electrical parameters or electrical quantities constituting the “immittance function” is emphasized. The “state of normalization” using physical geometrical factors can only be executed for a specific phenomenon when isolated from the total electrical behavior.

  16. Heat engine regenerators: Research status and needs

    Energy Technology Data Exchange (ETDEWEB)

    Hutchinson, R.A.

    1987-08-01

    The rapidly oscillating, variable density flows of regenerative heat engines provide a class of poorly understood unsteady flow and heat transfer problems. These problems are not currently amenable to direct experimental resolution. Experiences in engine development and test programs and efforts to develop analysis tools point to the regenerator as a key area of insufficient understanding. Focusing on flow and heat transfer in regenerators, this report discusses similarity parameters for the flows and reviews the experimental data currently available for Stirling analysis. Then a number of experimental results are presented from recent fundamental fluid mechanical and thermal investigations that shed additional light on the functioning of heat engine regenerators. Suggestions are made for approaches for further measurement and analysis efforts.

  17. Current Status of Tissue Engineering Heart Valve.

    Science.gov (United States)

    Shinoka, Toshiharu; Miyachi, Hideki

    2016-11-01

    The development of surgically implantable heart valve prostheses has contributed to improved outcomes in patients with cardiovascular disease. However, there are drawbacks, such as risk of infection and lack of growth potential. Tissue-engineered heart valve (TEHV) holds great promise to address these drawbacks as the ideal TEHV is easily implanted, biocompatible, non-thrombogenic, durable, degradable, and ultimately remodels into native-like tissue. In general, three main components used in creating a tissue-engineered construct are (1) a scaffold material, (2) a cell type for seeding the scaffold, and (3) a subsequent remodeling process driven by cell accumulation and proliferation, and/or biochemical and mechanical signaling. Despite rapid progress in the field over the past decade, TEHVs have not been translated into clinical applications successfully. To successfully utilize TEHVs clinically, further elucidation of the mechanisms for TEHV remodeling and further translational research outcome evaluations will be required. Tissue engineering is a major breakthrough in cardiovascular medicine that holds amazing promise for the future of reconstructive surgical procedures. In this article, we review the history of regenerative medicine, advances in the field, and state-of-the-art in valvular tissue engineering. © The Author(s) 2016.

  18. Uprated OMS engine status and future applications

    Science.gov (United States)

    Boyd, W. C.; Brasher, W. L.

    1986-01-01

    The baseline Orbital Maneuvering Engine (OME) of the Space Shuttle has the potential for significant performance uprating, leading to increased Shuttle performance capability. The approach to uprating that is being pursued at the NASA Lyndon B. Johnson Space Center is the use of a gas generator-driven turbopump to increase OME operating pressure. A higher pressure engine can have a greater nozzle expansion ratio in the same envelope and at the same thrust level, giving increased engine Isp. The results of trade studies and analyses that have led to the preferred uprated OME configuration are described. The significant accomplishments of a pre-development component demonstration program are also presented, including descriptions of test hardware and discussion of test results. It is shown that testing to date confirms the capability of the preferred uprated OME configuration to meet or exceed performance and life requirements. Potential future activities leading up to a full-scale development program are described, and the capability for the uprated OME to be used in future storable propellant upper stages is discussed.

  19. Status of CEFR Engineering Development in 2001

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In 2001, under the leadership of the Ministry of Science and Technology, the Commission of Science Technology and Industry for National Defense and the China National Nuclear Corporation, and the supervising of the National Nuclear Safety Administration, the China experimental fast reactor (CEFR) as one of the important items of the national "863" high technology project, has been made a remarkable progress by the hard work of the designers, the constructors and administrators of China Institute of Atomic Energy(CIAE).On March 14th, CEFR engineering has been approved to construct continuously by National

  20. Status of the CALICE AHCAL engineering prototype

    Energy Technology Data Exchange (ETDEWEB)

    Eldwan, Brianne [DESY (Germany); Collaboration: CALICE-D-Collaboration

    2015-07-01

    In the CALICE Collaboration are developed calorimeters for a future e{sup +}e{sup -} Linear Collider. One approach is called Particle Flow which requires highly granular calorimeters thus to achieve a jet energy resolution of 3-4%. The CALICE Collaboration is developing concepts and prototypes for Particle Flow optimized calorimeters with various readout technologies. The Analog Hadronic Calorimeter (AHCAL) is one of the concepts based on 3 x 3 cm{sup 2} scintillator tiles with Silicon Photomultipliers. The performance and suitability has been proven in the former physics prototype. The current focus of the second generation engineering prototype is on the full scalability of the detector. In 2014, two test beam periods happened at the PS at CERN, with an iron stack structure designed for the final detector (1 m{sup 3}) and 15 active layers (including 3 ScECAL layers). This talk focuses on the engineering prototype commissioning phase before testbeam, the monitoring of the calorimeter during data taking and a first look into the data taken at the PS.

  1. U.S. Nuclear Engineering Education: Status and Prospects.

    Science.gov (United States)

    National Academy of Sciences - National Research Council, Washington, DC. Commission on Engineering and Technical Systems.

    This study examines the status of and outlook for nuclear engineering (NE) in the United States. The study resulted from a concern about the downward trends in student enrollments in NE, in both graduate and undergraduate programs. Concerns have also been expressed about the declining number of U.S. university NE departments and programs, the…

  2. Characterizing SI Engine Transient Fuel Consumption in ALPHA

    Science.gov (United States)

    Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation.

  3. Characterizing SI Engine Transient Fuel Consumption in ALPHA

    Science.gov (United States)

    Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation.

  4. Molecular Tissue Engineering:Concepts,Status and Challenge

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Tissue engineering has confronted many difficulties mainly as follows:1)How to modulate the adherence,proliferation,and oriented differentiation of seed cells, especially that of stemcells. 2) Massive preparation and sustained controllable delivery of tissue inducing factors or plasmid DNA, such as growth factors, angiogenesis stimulators,and so on. 3) Development of "intelligent biomimetic materials" as extracellular matrix with a good superficial and structural compatibility as well as biological activity to stimulate predictable, controllable and desirable responses under defined conditions.Molecular biology is currently one of the most exciting fields of research across life sciences,and the advances in it also bring a bright future for tissue engineering to overcome these difficulties.In recent years,tissue engineering benefits a lot from molecular biology.Only a comprehensive understanding of the involved ingredients of tissue engineering (cells,tissue inducing factors,genes,biomaterials) and the subtle relationships between them at molecular level can lead to a successful manipulation of reparative processes and a better biological substitute.Molecular tissue engineering,the offspring of the tissue engineering and molecular biology,has gained an increasing importance in recent years.It offers the promise of not simply replacing tissue,but improving the restoration.The studies presented in this article put forward this new concept for the first time and provide an insight into the basic principles,status and challenges of this emerging technology.

  5. Characterization of Flow Bench Engine Testing

    Science.gov (United States)

    Voris, Alex; Riley, Lauren; Puzinauskas, Paul

    2015-11-01

    This project was an attempt at characterizing particle image velocimetry (PIV) and swirl-meter test procedures. The flow direction and PIV seeding were evaluated for in-cylinder steady state flow of a spark ignition engine. For PIV seeding, both wet and dry options were tested. The dry particles tested were baby powder, glass particulate, and titanium dioxide. The wet particles tested were fogs created with olive oil, vegetable oil, DEHS, and silicon oil. The seeding was evaluated at 0.1 and 0.25 Lift/Diameter and at cylinder pressures of 10, 25 and 40 inches of H2O. PIV results were evaluated through visual and fluid momentum comparisons. Seeding particles were also evaluated based on particle size and cost. It was found that baby powder and glass particulate were the most effective seeding options for the current setup. The oil fogs and titanium dioxide were found to deposit very quickly on the mock cylinder and obscure the motion of the particles. Based on initial calculations and flow measurements, the flow direction should have a negligible impact on PIV and swirl-meter results. The characterizations found in this project will be used in future engine research examining the effects of intake port geometry on in-cylinder fluid motion and exhaust gas recirculation tolerances. Thanks to NSF site grant #1358991.

  6. Mechanisms Engineering Test Loop - Phase 1 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Kultgen, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Grandy, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Hvasta, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Lisowski, D. [Argonne National Lab. (ANL), Argonne, IL (United States); Toter, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Borowski, A. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    This report documents the current status of the Mechanisms Engineering Test Loop (METL) as of the end of FY2016. Currently, METL is in Phase I of its design and construction. Once operational, the METL facility will test small to intermediate-scale components and systems in order to develop advanced liquid metal technologies. Testing different components in METL is essential for the future of advanced fast reactors as it will provide invaluable performance data and reduce the risk of failures during plant operation.

  7. 76 FR 5780 - Determination of Regulated Status of Alfalfa Genetically Engineered for Tolerance to the...

    Science.gov (United States)

    2011-02-02

    ... Animal and Plant Health Inspection Service Determination of Regulated Status of Alfalfa Genetically... regulated status of alfalfa genetically engineered for tolerance to the herbicide glyphosate based on APHIS... decision and determination on the petition regarding the regulated status of alfalfa genetically engineered...

  8. Characterization of surface hydrophobicity of engineered nanoparticles.

    Science.gov (United States)

    Xiao, Yao; Wiesner, Mark R

    2012-05-15

    The surface chemistry of nanoparticles, including their hydrophobicity, is a key determinant of their fate, transport and toxicity. Engineered NPs often have surface coatings that control the surface chemistry of NPs and may dominate the effects of the nanoparticle core. Suitable characterization methods for surface hydrophobicity at the nano-scale are needed. Three types of methods, surface adsorption, affinity coefficient and contact angle, were investigated in this study with seven carbon and metal based NPs with and without coatings. The adsorption of hydrophobic molecules, Rose Bengal dye and naphthalene, on NPs was used as one measure of hydrophobicity and was compared with the relative affinity of NPs for octanol or water phases, analogous to the determination of octanol-water partition coefficients for organic molecules. The sessile drop method was adapted for measuring contact angle of a thin film of NPs. Results for these three methods were qualitatively in agreement. Aqueous-nC(60) and tetrahydrofuran-nC(60) were observed to be more hydrophobic than nano-Ag coated with polyvinylpyrrolidone or gum arabic, followed by nano-Ag or nano-Au with citrate-functionalized surfaces. Fullerol was shown to be the least hydrophobic of seven NPs tested. The advantages and limitations of each method were also discussed.

  9. Status of the Boeing Dish Engine Critical Component Project

    Energy Technology Data Exchange (ETDEWEB)

    Brau, H.W.; Diver, R.B.; Nelving, H.; Stone, K.W.

    1999-01-08

    The Boeing Company's Dish Engine Critical Component (DECC) project started in April of 1998. It is a continuation of a solar energy program started by McDonnell Douglas (now Boeing) and United Stirling of Sweden in the mid 1980s. The overall objectives, schedule, and status of this project are presented in this paper. The hardware test configuration, hardware background, operation, and test plans are also discussed. A summary is given of the test data, which includes the daily power performance, generated energy, working-gas usage, mirror reflectivity, solar insolation, on-sun track time, generating time, and system availability. The system performance based upon the present test data is compared to test data from the 1984/88 McDonnell Douglas/United Stirling AB/Southem California Edison test program. The test data shows that the present power, energy, and mirror performance is comparable to when the hardware was first manufactured 14 years ago.

  10. SIM-Lite: status of the engineering progress toward flight

    Science.gov (United States)

    Dekens, Frank G.; Bloemhof, Eric E.; Dubovitsky, Serge; Eldred, Daniel; Goullioud, Renaud; Jeganathan, Muthu; Nicaise, Fabien; Zhao, Feng

    2008-07-01

    We present an overview of the ongoing progress towards flight readiness of the SIM project. We summarize the engineering milestones that have been completed in the last two years, namely: the Brass-Board Internal and External Metrology Beam Launchers, the Brass-Board Metrology Source, and the Instrument Communication Hardware/Software Architecture Demonstration. We also show other progress such as: the life test of the bass-screw and PZT actuators, building the Metrology Fiducials and the Single Strut Test Article. We status the ongoing work on the Brass-Board Fast Steering Mirror and the Brass-Board Astrometric Beam Combiner. We end with a proposed path towards finishing the Brass-Board suite.

  11. Civil engineering status report for the ATLAS & CMS worksites

    CERN Document Server

    Rammer, H; CERN. Geneva. ST Division

    2003-01-01

    Construction work on the civil engineering contracts at Point 1 and Point 5 started in 1998. The new surface buildings and underground structures are necessary to accommodate the ATLAS and CMS detectors for the LHC Project. The principal underground works at both points consist of two new shafts, two caverns along with a number of small connection tunnels and galleries. At Point 1, the works are 90% complete. Most of the surface buildings as well as the shafts and one of the two new caverns have been completed, and the construction of the second cavern is well underway. At Point 5, the works are 70% complete. Most of the surface buildings as well as the shafts and the pillar have been completed. With excavation of the two large caverns complete, the concreting of the final linings has started. The aim of this paper is to present the status of the civil engineering on these worksites and in particular the challenges encountered constructing the experimental caverns.

  12. Systems biology characterization of engineered tissues.

    Science.gov (United States)

    Rajagopalan, Padmavathy; Kasif, Simon; Murali, T M

    2013-01-01

    Tissue engineering and molecular systems biology are inherently interdisciplinary fields that have been developed independently so far. In this review, we first provide a brief introduction to tissue engineering and to molecular systems biology. Next, we highlight some prominent applications of systems biology techniques in tissue engineering. Finally, we outline research directions that can successfully blend these two fields. Through these examples, we propose that experimental and computational advances in molecular systems biology can lead to predictive models of bioengineered tissues that enhance our understanding of bioengineered systems. In turn, the unique challenges posed by tissue engineering will usher in new experimental techniques and computational advances in systems biology.

  13. Radiological Characterization and Final Facility Status Report Tritium Research Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, T.B.; Gorman, T.P.

    1996-08-01

    This document contains the specific radiological characterization information on Building 968, the Tritium Research Laboratory (TRL) Complex and Facility. We performed the characterization as outlined in its Radiological Characterization Plan. The Radiological Characterization and Final Facility Status Report (RC&FFSR) provides historic background information on each laboratory within the TRL complex as related to its original and present radiological condition. Along with the work outlined in the Radiological Characterization Plan (RCP), we performed a Radiological Soils Characterization, Radiological and Chemical Characterization of the Waste Water Hold-up System including all drains, and a Radiological Characterization of the Building 968 roof ventilation system. These characterizations will provide the basis for the Sandia National Laboratory, California (SNL/CA) Site Termination Survey .Plan, when appropriate.

  14. A Novel Gas Turbine Engine Health Status Estimation Method Using Quantum-Behaved Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Xinyi Yang

    2014-01-01

    Full Text Available Accurate gas turbine engine health status estimation is very important for engine applications and aircraft flight safety. Due to the fact that there are many to-be-estimated parameters, engine health status estimation is a very difficult optimization problem. Traditional gas path analysis (GPA methods are based on the linearized thermodynamic engine performance model, and the estimation accuracy is not satisfactory on conditions that the nonlinearity of the engine model is significant. To solve this problem, a novel gas turbine engine health status estimation method has been developed. The method estimates degraded engine component parameters using quantum-behaved particle swarm optimization (QPSO algorithm. And the engine health indices are calculated using these estimated component parameters. The new method was applied to turbine fan engine health status estimation and is compared with the other three representative methods. Results show that although the developed method is slower in computation speed than GPA methods it succeeds in estimating engine health status with the highest accuracy in all test cases and is proven to be a very suitable tool for off-line engine health status estimation.

  15. E-ELT site characterization status

    Science.gov (United States)

    Vernin, J.; Muñoz-Tuñon, C.; Sarazin, M.

    2008-07-01

    The site selection for the future European Large Telescope (E-ELT) is a key issue within the European proposal funded by the EC, within the "ELT Design Study" proposal. The organization, working scheme and baseline frameworks are reviewed. For the definition of the working package WP12000 "Site Characterization" important use has been done of previous works in the definition of techniques and tools for the study of the atmosphere above observing sites. We have also taken advantage of the number of data already available which have naturally defined a ranking among the known places which have also been taken as a base line for pre-selecting the candidate sites. The work will last 4 years, started in 2005 and is organized in subtasks whose main objectives are the following: WP12100: To characterize two top astronomical sites (ORM and North-Paranal) and to explore 3 other alternatives (Macon in Argentina, Izana in Spain and Aklim in Morocco) suitable to install an ELT under the best conditions (Dome C is been currently under investigation, and no particular effort will be put in this site, but rather its atmospheric properties will be compared to the above mentioned sites). WP12200 is dedicated to design, build and operate a standard equipment in all the sites and to perform long term campaign. WP12300 will investigate wavefront properties over large baselines (50-100 m) corresponding to the size of the future ELT, as well as the fine characterization of the optical turbulence within the boundary layer.

  16. Characterization of lubrication oil emissions from aircraft engines.

    Science.gov (United States)

    Yu, Zhenhong; Liscinsky, David S; Winstead, Edward L; True, Bruce S; Timko, Michael T; Bhargava, Anuj; Herndon, Scott C; Miake-Lye, Richard C; Anderson, Bruce E

    2010-12-15

    In this first ever study, particulate matter (PM) emitted from the lubrication system overboard breather vent for two different models of aircraft engines has been systematically characterized. Lubrication oil was confirmed as the predominant component of the emitted particulate matter based upon the characteristic mass spectrum of the pure oil. Total particulate mass and size distributions of the emitted oil are also investigated by several high-sensitivity aerosol characterization instruments. The emission index (EI) of lubrication oil at engine idle is in the range of 2-12 mg kg(-1) and increases with engine power. The chemical composition of the oil droplets is essentially independent of engine thrust, suggesting that engine oil does not undergo thermally driven chemical transformations during the ∼4 h test window. Volumetric mean diameter is around 250-350 nm for all engine power conditions with a slight power dependence.

  17. Genetic engineering in Cowpea (Vigna unguiculata): history, status and prospects.

    Science.gov (United States)

    Citadin, Cristiane T; Ibrahim, Abdulrazak B; Aragão, Francisco J L

    2011-01-01

    In the last three decades, a number of attempts have been made to develop reproducible protocols for generating transgenic cowpea that permit the expression of genes of agronomic importance. Pioneer works focused on the development of such systems vis-à-vis an in vitro culture system that would guarantee de novo regeneration of transgenic cowpea arising from cells amenable to one form of gene delivery system or another, but any such system has eluded researchers over the years. Despite this apparent failure, significant progress has been made in generating transgenic cowpea, bringing researchers much nearer to their goal than thirty years ago. Now, various researchers have successfully established transgenic procedures for cowpea with evidence of inherent transgenes of interest, effected by progenies in a Mendelian fashion. New opportunities have thus emerged to optimize existing protocols and devise new strategies to ensure the development of transgenic cowpea with desirable agronomic traits. This review chronicles the important milestones in the last thirty years that have marked the evolution of genetic engineering of cowpea. It also highlights the progress made and describes new strategies that have arisen, culminating in the current status of transgenic technologies for cowpea.

  18. Biochemical Engineering Education in Japan - A Survey of the Status as It Is.

    Science.gov (United States)

    Unno, Hajime

    2000-01-01

    Summary of the survey questionnaire on biochemical engineering education in Japanese universities. The questionnaire was distributed to the academic professors whose research fields included biochemical engineering. The questionnaire was intended to sufficiently realize the present status of biochemical engineering education in Japan. (Author/SAH)

  19. Evaluation of mass spectrometric techniques for characterization of engineered proteins

    DEFF Research Database (Denmark)

    Roepstorff, P; Schram, K H; Andersen, Jens S.;

    1995-01-01

    Mass spectrometric characterization of engineered proteins has been examined using bovine recombinant Acyl-CoA-Binding Protein (rACBP), [15N]-labeled rACBP, and a number of sequence variants of ACBP produced by site-directed mutagenesis. The mass spectrometric techniques include ESIMS and MALDIMS...... was obtained by LC-ESIMS and by direct mixture analysis by MALDIMS. The latter technique was favorable in terms of sensitivity and speed. A general strategy for mass spectrometric characterization of engineered proteins is suggested....

  20. The status and challenges of Industrial Engineering in South Africa

    Directory of Open Access Journals (Sweden)

    Schutte, Cornelius S. L.

    2016-05-01

    Full Text Available The industrial engineering discipline in South Africa is examined by introducing the context of the discipline and by revisiting its history. The drivers influencing the context and future of industrial engineering in South Africa are also considered, and the discipline is analysed in terms of the following aspects: university qualifications, employment in industry sectors, race and gender profiles, use and competence in industry, and income profiles. The analysis is based on a recent survey sent to practising industrial engineers, on membership data from the Southern African Institute for Industrial Engineering (SAIIE, and on two internal SAIIE investigations. The study concludes that the success of transformation, particularly in terms of race, has been limited. The results also indicate that there are an almost equal number of black and white industrial engineers, yet the majority of black industrial engineers have technical qualifications, while the majority of white industrial engineers have academic qualifications. The results indicate that this limits the use of black industrial engineers in industry and, consequently, the success of their careers. This in turn means that there are fewer black role models to attract young black students to the discipline. Some preliminary opportunities to unlock the increased transformation of the profession are identified.

  1. Growth of Engineering Education in India: Status, Issues, and Challenges

    Science.gov (United States)

    Choudhury, Pradeep Kumar

    2016-01-01

    This article examines the growth of engineering education in India in the post-economic reform period using the secondary data published by Ministry of Human Resource Development, University Grants Commission and All India Council for Technical Education. Particularly, this article has focused on three important dimensions of engineering and…

  2. Semiconductor/dielectric interface engineering and characterization

    Science.gov (United States)

    Lucero, Antonio T.

    The focus of this dissertation is the application and characterization of several, novel interface passivation techniques for III-V semiconductors, and the development of an in-situ electrical characterization. Two different interface passivation techniques were evaluated. The first is interface nitridation using a nitrogen radical plasma source. The nitrogen radical plasma generator is a unique system which is capable of producing a large flux of N-radicals free of energetic ions. This was applied to Si and the surface was studied using x-ray photoelectron spectroscopy (XPS). Ultra-thin nitride layers could be formed from 200-400° C. Metal-oxide-semiconductor capacitors (MOSCAPs) were fabricated using this passivation technique. Interface nitridation was able to reduce leakage current and improve the equivalent oxide thickness of the devices. The second passivation technique studied is the atomic layer deposition (ALD) diethylzinc (DEZ)/water treatment of sulfur treated InGaAs and GaSb. On InGaAs this passivation technique is able to chemically reduce higher oxidation states on the surface, and the process results in the deposition of a ZnS/ZnO interface passivation layer, as determined by XPS. Capacitance-voltage (C-V) measurements of MOSCAPs made on p-InGaAs reveal a large reduction in accumulation dispersion and a reduction in the density of interfacial traps. The same technique was applied to GaSb and the process was studied in an in-situ half-cycle XPS experiment. DEZ/H2O is able to remove all Sb-S from the surface, forming a stable ZnS passivation layer. This passivation layer is resistant to further reoxidation during dielectric deposition. The final part of this dissertation is the design and construction of an ultra-high vacuum cluster tool for in-situ electrical characterization. The system consists of three deposition chambers coupled to an electrical probe station. With this setup, devices can be processed and subsequently electrically characterized

  3. Applications of Engineering Seismology for Site Characterization

    Institute of Scientific and Technical Information of China (English)

    Oz Yilmaz; Murat Eser; Mehmet Berilgen

    2009-01-01

    We determined the seismic model of the soil column within a residential project site in Istanbul, Turkey. Specifically, we conducted a refraction seismic survey at 20 locations using a receiver spread with 484.5-Hz vertical geophones at 2-m intervals. We applied nonlinear tomography to first-arrival times to estimate the P-wave velocity-depth profiles and performed Rayleigh-wave inversion to estimate the S-wave velocity-depth profiles down to a depth of 30 m at each of the locations. We then combined the seismic velocities with the geotechnical borehole information regarding the lithology of the soil column and determined the site-specific geotechnical earthquake engineering parameters for the site. Specifically, we computed the maximum soil amplification ratio, maximum surface-bedrock acceleration ratio, depth interval of significant acceleration, maximum soil-rock response ratio, and design spectrum periods TA-TB. We conducted reflection seismic surveys along five line traverses with lengths between 150 and 300 m and delineated landslide failure surfaces within the site. We recorded shot gathers at 2-m intervals along each of the seismic line traverses using a receiver spread with 4 840-Hz vertical geophones at 2-m intervals. We applied nonlinear tomograpby to first-arrival times to estimate a P-wave velocity-depth model and analyzed the reflected waves to obtain a seismic image of the deep near-surface along each of the line traverses.

  4. Research status of key techniques for shock-induced combustion ramjet(shcramjet) engine

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    As one of the most promising propulsion systems in the future,shock-induced combustion ramjet engine can remedy the disadvantages in the integrated design of scramjet engine and airframe.It can shorten the length of the combustor,lighten the structure weight of the engine and keep better performance in a broad range of flight Mach number.The elementary principle of shock-induced combustion ramjet engine is introduced.The key technologies of this kind of propulsion system are described,while their research status is presented in detail.Suggestion on the development of shcramjet engine in China is put forward.

  5. Characterizing Vineyard Water Status Variability in a Premium Winegrape Vineyard

    Science.gov (United States)

    Smart, David; Carvahlo, Angela

    2017-04-01

    One of the biggest challenges in viticulture and winemaking is managing and optimizing yield and quality across vineyard blocks that show high spatial variability. Studies have shown that zonal management of vine water status can contribute significantly to improving overall fruit quality and improving uniformity. Vine water status is a major parameter for vine management because it affects both wine quality and yield. In order to optimize vineyard management and harvesting practices, it is necessary to characterize vineyard variability in terms of water status. Establishing a targeted irrigation program first requires spatially characterizing the variability in vine water status of a vineyard. In California, due to the low or no rainfall during the active growing season, the majority of vineyards implement some type of irrigation management program. As water supplies continue to decrease as a consequence of persistent drought, establishing efficient and targeted water use programs is of growing importance in California. The aim of this work was to characterize the spatial variability of plant-water relations across a non-uniform 4 ha block in Napa Valley with the primary objective of establishing vineyard irrigation management zones. The study plot was divided into three sections, designated the North, Middle and South sections, each at about 1.3 hectares. Stem (Ψstem) and midday (Ψl) leaf water potential and predawn (ΨPD) water potential were measured at 36 locations within the block at 14 (Ψl), 10 (ΨPD) and 2 (Ψstem) points in time throughout the growing season. Of the three techniques utilized to evaluate water status, ΨPD and Ψstem were the most sensitive indicators of water stress conditions. An integrated overview of water use efficiency over the growing season was assessed by measuring the leaf carbon isotope ratio of δ13C. Fully mature leaves were sampled from 280 vines and results show, similarly to ΨPD and Ψstem, that the North section (-28

  6. The status and challenges of Industrial Engineering in South Africa

    OpenAIRE

    Schutte, Cornelius S. L.; Kennon, Denzil; Bam, Wouter

    2016-01-01

    The industrial engineering discipline in South Africa is examined by introducing the context of the discipline and by revisiting its history. The drivers influencing the context and future of industrial engineering in South Africa are also considered, and the discipline is analysed in terms of the following aspects: university qualifications, employment in industry sectors, race and gender profiles, use and competence in industry, and income profiles. The analysis is based on a recent survey ...

  7. Uprated OMS Engine Status-Sea Level Testing Results

    Science.gov (United States)

    Bertolino, J. D.; Boyd, W. C.

    1990-01-01

    The current Space Shuttle Orbital Maneuvering Engine (OME) is pressure fed, utilizing storable propellants. Performance uprating of this engine, through the use of a gas generator driven turbopump to increase operating pressure, is being pursued by the NASA Johnson Space Center (JSC). Component level design, fabrication, and test activities for this engine system have been on-going since 1984. More recently, a complete engine designated the Integrated Component Test Bed (ICTB), was tested at sea level conditions by Aerojet. A description of the test hardware and results of the sea level test program are presented. These results, which include the test condition operating envelope and projected performance at altitude conditions, confirm the capability of the selected Uprated OME (UOME) configuration to meet or exceed performance and operational requirements. Engine flexibility, demonstrated through testing at two different operational mixture ratios, along with a summary of projected Space Shuttle performance enhancements using the UOME, are discussed. Planned future activities, including ICTB tests at simulated altitude conditions, and recommendations for further engine development, are also discussed.

  8. Bacteria engineered for fuel ethanol production: current status

    Energy Technology Data Exchange (ETDEWEB)

    Dien, B.S.; Cotta, M.A. [National Center for Agricultural Utilization Research, Agricultural Research Service, USDA, Peoria, IL (United States); Jeffries, T.W. [Inst. for Microbial and Biochemical Technology, Forest Service, Forest Products Lab., USDA, Madison, WI (United States)

    2004-07-01

    The lack of industrially suitable microorganisms for converting biomass into fuel ethanol has traditionally been cited as a major technical roadblock to developing a bioethanol industry. In the last two decades, numerous microorganisms have been engineered to selectively produce ethanol. Lignocellulosic biomass contains complex carbohydrates that necessitate utilizing microorganisms capable of fermenting sugars not fermentable by brewers' yeast. The most significant of these is xylose. The greatest successes have been in the engineering of gram-negative bacteria: Escherichia coli, Klebsiella oxytoca, and Zymomonas mobilis. E. coli and K. oxytoca are naturally able to use a wide spectrum of sugars, and work has concentrated on engineering these strains to selectively produce ethanol. Z. mobilis produces ethanol at high yields, but ferments only glucose and fructose. Work on this organism has concentrated on introducing pathways for the fermentation of arabinose and xylose. The history of constructing these strains and current progress in refining them are detailed in this review. (orig.)

  9. Undergraduate engineering student experiences: Comparing sex, gender and switcher status

    Science.gov (United States)

    Fergen, Brenda Sue

    This dissertation explores undergraduate engineering experiences, comparing men with women and switchers with non-switchers. Factors related to a chilly academic climate and gender-role socialization are hypothesized to contribute to variations in men's and women's academic experiences and persistence rates. Both quantitative and qualitative data are utilized in an effort to triangulate the findings. Secondary survey data, acquired as result of a 1992 Academic Environment Survey, were utilized to test the hypothesis that sex is the most important predictor (i.e., demographic variable) of perceptions of academic climate. Regression analyses show that sex by itself is not always a significant determinant. However, when sex and college (engineering vs. other) are combined into dummy variables, they are statistically significant in models where sex was not significant alone. This finding indicates that looking at sex differences alone may be too simplistic. Thirty personal interviews were conducted with a random stratified sample of undergraduate students from the 1993 engineering cohort. The interview data indicate that differences in childhood socialization are important. With regard to persistence, differences in socialization are greater for switchers vs. non-switchers than men vs. women. Thus, gender-role socialization does not appear to play as prominent a role in women's persistence as past literature would indicate. This may be due to the self-selection process that occurs among women who choose to pursue engineering. Other aspects of childhood socialization such as parents' level of educational and occupation, students' high school academic preparation and knowledge of what to expect of college classes appear to be more important. In addition, there is evidence that, for women, male siblings play an important role in socialization. There is also evidence that women engineering students at Midwestern University face a chilly academic climate. The factors which

  10. Catastrophe theory and its application status in mechanical engineering

    Directory of Open Access Journals (Sweden)

    Jinge LIU

    Full Text Available Catastrophe theory is a kind of mathematical method which aims to apply and interpret the discontinuous phenomenon. Since its emergence, it has been widely used to explain a variety of emergent phenomena in the fields of natural science, social science, management science and some other science and technology fields. Firstly, this paper introduces the theory of catastrophe in several aspects, such as its generation, radical principle, basic characteristics and development. Secondly, it summarizes the main applications of catastrophe theory in the field of mechanical engineering, focusing on the research progress of catastrophe theory in revealing catastrophe of rotor vibration state, analyzing friction and wear failure, predicting metal fracture, and so on. Finally, it advises that later development of catastrophe theory should pay more attention to the combination of itself with other traditional nonlinear theories and methods. This paper provides a beneficial reference to guide the application of catastrophe theory in mechanical engineering and related fields for later research.

  11. The Efficiency of the Smoke Meter at Characterizing Engine Emissions

    Science.gov (United States)

    Paladino, Jonathan D.

    1997-01-01

    The effectiveness of a smoke meter's ability to characterize the particulate emissions of a jet fuel combustor was evaluated using the University of Missouri-Rolla Mobile Aerosol Sampling System (UMR-MASS). A burner simulating an advanced jet engine combustor design was used to generate typical combustion particulates, which were then analyzed by the smoke meter. The same particulates were then size discriminated to ascertain the effective impact of aerosol diameter on smoke number readings.

  12. Status report on a real time Engine Diagnostics Console for rocket engine exhaust plume monitoring

    Science.gov (United States)

    Bircher, F. E.; Gardner, D. G.; Vandyke, D. B.; Harris, A. B.; Chenevert, D. J.

    1990-01-01

    This paper describes the work done on the Engine Diagnostics Console during the past year of development at Stennis Space Center. The Engine Diagnostics Console (EDC) is a hardware and software package which provides near real time monitoring of rocket engine exhaust plume emissions during ground testing. The long range goal of the EDC development program is to develop an instrument that can detect engine degradation leading to catastrophic failure, and respond by taking preventative measures. The immediate goal for the past year's effort is the ability to process spectral data, taken from a rocket engine's exhaust plume, and to identify in an automated and high speed manner, the elemental species and multielemental materials that are present in the exhaust plume.

  13. Status report - DARPA/NASA convertible turbofan/turboshaft engine program

    Science.gov (United States)

    Bellin, A. I.; Brooks, A.

    1983-01-01

    A development status report is presented for the NASA/Defense Advanced Research Projects Agency convertible turbofan-turboshaft engine, which can power a high speed rotorcraft in vertical flight, as well as in horizontal flight up to speeds of Mach 0.85. The basis for this development program is a modified TF34-GE-400 engine. Program objectives include both the demonstration of dual output mode (jet thrust and shaft horsepower) capability and the development of a control system which will operate the engine in either mode and convert operation between the modes.

  14. Carbonate reservoir characterization. A geologic-engineering analysis. Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Chilingarian, G.V. [School of Engineering, University of Southern California, Los Angeles (United States); Mazzullo, S.J. [Geology Department, Wichita State University, Wichita (United States); Rieke, H.H. [Petroleum Engineering Department, University of Southwestern Louisiana, Lafayette (United States); Dominguez, G.C.; Samaniego, F. [eds.

    1996-12-31

    This second volume on carbonate reservoirs completes the two-volume treatise on this important topic to petroleum engineers and geologists. The two volumes form a complete and modern reference work to the properties and production behavior of carbonate petroleum reservoirs. This volume contains valuable glossaries to geologic and petroleum engineering terms providing exact definitions for writers and speakers. Professors will find a useful appendix devoted to questions and problems that can be used for teaching assignments as well as a guide for lecture development. In addition, there is a chapter devoted to core analysis of carbonate rocks which is ideal for laboratory instruction. Managers and production engineers will find a review of the latest laboratory technology for carbonate formation evaluation in the chapter on core analysis. The modern classification of carbonate rocks is presented with petroleum production performance and overall characterization using seismic and well test analyses. Separate chapters are devoted to the important naturally fractured and chalk reservoirs. Throughout the book, the emphasis is on formation evaluation and performance. The importance of carbonate reservoirs lies in the fact that they contain as much as 50% of the total petroleum reserves of the world. This is sometimes masked by the uniquely different properties and production performance characteristics of carbonate reservoirs because of their heterogeneity and the immense diversity that exists among them. This two-volume treatise brings together the wide variety of approaches to the study of carbonate reservoirs and, therefore, will fit the needs of managers, engineers, geologists and teachers. figs., tabs., refs.

  15. Status of the Yucca Mountain site characterization program

    Energy Technology Data Exchange (ETDEWEB)

    Gertz, C.P.; Nelson, R.M. [Jacobs Engineering Group, Inc., Albuquerque, NM (United States); Blanchard, M.B. [Department of Energy, Las Vegas, NV (United States); Cloke, P.L. [Science Applications International Corporation, Las Vegas, NV (United States)

    1994-12-31

    By its very nature the Yucca Mountain Site Characterization Program (YMP) entails a complex set of activities and issues. Among these are planning for the Exploratory Studies Facility (ESF), site characterization surface-based testing, performance assessment, public outreach and information services, conceptual design of a potential repository, compliance with regulations, environmental issues, transportation of nuclear wastes, and systems engineering. Stringent safety and health standards apply to all these activities, which must also be carried out under rigorous quality assurance controls. This session includes individual papers on several of these topics. The present paper provides a less comprehensive overview. Project goals for fiscal year 1994 focus on the continuation of the following activities: Development of the ESF pursuant to the earliest possible determination of site suitability; advanced conceptual design of both the waste package and repository to the degree necessary for ESF development and the Mined Geologic Disposal system; implementation of the surface-based testing program pursuant to the earliest possible determination of site suitability; compilation of environmental data necessary for the earliest possible determination of site suitability; identification and pursuit of resolution of difficult technical issues that bear on the overall suitability of the site; support for development of a design for standardized spent-fuel containers for storage, transportation, and disposal; needed compliance with all applicable YMP commitments and Department of Energy order and regulations to ensure safety and regulatory compliance for all parts of the program; and definition and implementation of cost reduction initiatives consistent with the overall goals of the Project.

  16. Status of MODIS spatial and spectral characterization and performance

    Science.gov (United States)

    Link, Dan; Wang, Zhipeng; Xiong, Xiaoxiong

    2016-05-01

    Since launch, both Terra and Aqua MODIS instruments have continued to operate and make measurements of the earth's top of atmospheric (TOA) radiances and reflectance. MODIS collects data in 36 spectral bands covering wavelengths from 0.41 to 14.4 μm. These spectral bands and detectors are located on four focal plane assemblies (FPAs). MODIS on-board calibrators (OBC) include a spectro-radiometric calibration assembly (SRCA), which was designed to characterize and monitor sensor spatial and spectral performance, such as on-orbit changes in the band-to-band registration (BBR), modulation transfer function (MTF), spectral band center wavelengths (CW) and bandwidths (BW). In this paper, we provide a status update of MODIS spatial and spectral characterization and performance, following a brief description of SRCA functions and on-orbit calibration activities. Sensor spatial and spectral performance parameters derived from SRCA measurements are introduced and discussed. Results show that on-orbit spatial performance has been very stable for both Terra and Aqua MODIS instruments. The large BBR shifts in Aqua MODIS, an issue identified pre-launch, have remained the same over its entire mission. On-orbit changes in CW and BW are less than 0.5 nm and 1 nm, respectively, for most VIS/NIR spectral bands of both instruments.

  17. Development Status of High-Thrust Density Electrostatic Engines

    Science.gov (United States)

    Patterson, Michael J.; Haag, Thomas W.; Foster, John E.; Young, Jason A.; Crofton, Mark W.

    2017-01-01

    Ion thruster technology offers the highest performance and efficiency of any mature electric propulsion thruster. It has by far the highest demonstrated total impulse of any technology option, demonstrated at input power levels appropriate for primary propulsion. It has also been successfully implemented for primary propulsion in both geocentric and heliocentric environments, with excellent ground/in-space correlation of both its performance and life. Based on these attributes there is compelling reasoning to continue the development of this technology: it is a leading candidate for high power applications; and it provides risk reduction for as-yet unproven alternatives. As such it is important that the operational limitations of ion thruster technology be critically examined and in particular for its application to primary propulsion its capabilities relative to thrust the density and thrust-to-power ratio be understood. This publication briefly addresses some of the considerations relative to achieving high thrust density and maximizing thrust-to-power ratio with ion thruster technology, and discusses the status of development work in this area being executed under a collaborative effort among NASA Glenn Research Center, the Aerospace Corporation, and the University of Michigan.

  18. Subsidence characterization and modeling for engineered facilities in Arizona, USA

    Science.gov (United States)

    Rucker, M. L.; Fergason, K. C.; Panda, B. B.

    2015-11-01

    Several engineered facilities located on deep alluvial basins in southern Arizona, including flood retention structures (FRS) and a coal ash disposal facility, have been impacted by up to as much as 1.8 m of differential land subsidence and associated earth fissuring. Compressible basin alluvium depths are as deep as about 300 m, and historic groundwater level declines due to pumping range from 60 to more than 100 m at these facilities. Addressing earth fissure-inducing ground strain has required alluvium modulus characterization to support finite element modeling. The authors have developed Percolation Theory-based methodologies to use effective stress and generalized geo-material types to estimate alluvium modulus as a function of alluvium lithology, depth and groundwater level. Alluvial material modulus behavior may be characterized as high modulus gravel-dominated, low modulus sand-dominated, or very low modulus fines-dominated (silts and clays) alluvium. Applied at specific aquifer stress points, such as significant pumping wells, this parameter characterization and quantification facilitates subsidence magnitude modeling at its' sources. Modeled subsidence is then propagated over time across the basin from the source(s) using a time delay exponential decay function similar to the soil mechanics consolidation coefficient, only applied laterally. This approach has expanded subsidence modeling capabilities on scales of engineered facilities of less than 2 to more than 15 km.

  19. Tracer Methods for Characterizing Fracture Creation in Engineered Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Peter [Energy & Geoscience Institute at the University of Utah, Salt Lake City, UT (United States); Harris, Joel [Univ. of Utah, Salt Lake City, UT (United States)

    2014-05-08

    The aim of this proposal is to develop, through novel high-temperature-tracing approaches, three technologies for characterizing fracture creation within Engineered Geothermal Systems (EGS). The objective of a first task is to identify, develop and demonstrate adsorbing tracers for characterizing interwell reservoir-rock surface areas and fracture spacing. The objective of a second task is to develop and demonstrate a methodology for measuring fracture surface areas adjacent to single wells. The objective of a third task is to design, fabricate and test an instrument that makes use of tracers for measuring fluid flow between newly created fractures and wellbores. In one method of deployment, it will be used to identify qualitatively which fractures were activated during a hydraulic stimulation experiment. In a second method of deployment, it will serve to measure quantitatively the rate of fluid flowing from one or more activated fracture during a production test following a hydraulic stimulation.

  20. Status of Undergraduate Engineering Education in India--An Analysis of Accredited Engineering Programmes

    Science.gov (United States)

    Viswanadhan, K. G.

    2008-01-01

    National Board of Accreditation (NBA), a body constituted by the All India Council for Technical Education (AICTE) is responsible for the accreditation of Technical education programmes in India. NBA evaluates the performance of engineering programmes quantitatively by assessing 70 variables grouped under a set of 8 predefined criteria, and…

  1. Letter of Intent for RPP Characterization Program Process Engineering and Hanford Analytical Services and Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    ADAMS, M.R.

    2000-02-25

    The Characterization Project level of success achieved by the River Protection Project (RPP) is determined by the effectiveness of several organizations across RPP working together. The requirements, expectations, interrelationships, and performance criteria for each of these organizations were examined in order to understand the performances necessary to achieve characterization objectives. This Letter of Intent documents the results of the above examination. It formalizes the details of interfaces, working agreements, and requirements for obtaining and transferring tank waste samples from the Tank Farm System (RPP Process Engineering, Characterization Project Operations, and RPP Quality Assurance) to the characterization laboratory complex (222-S Laboratory, Waste Sampling and Characterization Facility, and the Hanford Analytical Service Program) and for the laboratory complex analysis and reporting of analytical results.

  2. Engineering

    National Research Council Canada - National Science Library

    Includes papers in the following fields: Aerospace Engineering, Agricultural Engineering, Chemical Engineering, Civil Engineering, Electrical Engineering, Environmental Engineering, Industrial Engineering, Materials Engineering, Mechanical...

  3. MELiSSA Food Characterization general approach and current status

    Science.gov (United States)

    Weihreter, Martin; Chaerle, Laury; Secco, Benjamin; Molders, Katrien; van der Straeten, Dominique; Duliere, Eric; Pieters, Serge; Maclean, Heather; Dochain, Denis; Quinet, Muriel; Lutts, Stanley; Graham, Thomas; Stasiak, Michael; Rondeau Vuk, Theresa; Zheng, Youbin; Dixon, Mike; Laniau, Martine; Larreture, Alain; Timsit, Michel; Aronne, Giovanna; Barbieri, Giancarlo; Buonomo, Roberta; Veronica; Paradiso, Roberta; de Pascale, Stafania; Galbiati, Massimo; Troia, A. R.; Nobili, Matteo; Bucchieri, Lorenzo; Page, Valérie; Feller, Urs; Lasseur, Christophe

    . Available MELiSSA closed environment crop growth data were used to develop a first photosynthetic model representing the basic carbon fixation mechanisms. This model will be further elaborated in the course of this study to predict yield, oxygen production and transpi-ration. As an ultimate goal the model is intended to simulate the composition of the different plant organs (root, shoot, fruit/seed or tuber) for each crop under various conditions. For the validation of this model an extensive amount of data sets are needed. Current plant growth bench test setups will provide part of the required data. To gain more precise and detailed datasets, a highly closed plant growth chamber (Plant Characterization Unit, PCU) is under development. The PCU will provide accurate mass balances for carbon, water, oxygen and other elements with statistical reliability. This reliability is achieved through a high degree of closure and environment homogeneity. The PCU will also provide data for the above described plant characterization studies. The general work approach, the current status and future steps will be illustrated.

  4. Status of several Stirling loss characterization efforts and their significance for Stirling space power development

    Science.gov (United States)

    Tew, Roy C., Jr.

    1988-01-01

    NASA-Lewis and other U.S. Government agencies have supported experimental and analytical programs for the characterization of Stirling cycle engines' thermodynamic losses, with a view to the improvement of Stirling engine design capabilities. The Space Power Demonstrator Engine is noted to have benefited from these efforts; test data and model predictions suggest that even greater performance improvements would be obtainable through additional modifications of engine regenerator and heater hardware.

  5. Physical characterization of hydroxyapatite porous scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, S., E-mail: smsilva@ineb.up.pt [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalurgica e Materiais, Porto (Portugal); Rodriguez, M.A.; Pena, P.; De Aza, A.H.; De Aza, S. [Instituto de Ceramica y Vidrio, CSIC, 28049-Cantoblanco, Madrid (Spain); Ferraz, M.P. [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Faculdade de Ciencias da Saude da Universidade Fernando Pessoa, Rua Carlos da Maia, 296, 4200-150 Porto (Portugal); Monteiro, F.J. [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalurgica e Materiais, Porto (Portugal)

    2009-06-01

    The present study refers to the preparation and characterization of porous hydroxyapatite scaffolds to be used as matrices for bone regeneration or as specific release vehicles. Ceramics are widely used for bone tissue engineering purposes and in this study, hydroxyapatite porous scaffolds were produced using the polymer replication method. Polyurethane sponges were used as templates and impregnated with a ceramic slurry at different ratios, and sintered at 1300 deg. C following a specific thermal cycle. The characteristics of the hydroxyapatite porous scaffolds and respective powder used as starting material, were investigated by using scanning electron microscopy, particle size distribution, X-ray diffraction, Fourier transformed infrared spectroscopy and compressive mechanical testing techniques. It was possible to produce highly porous hydroxyapatite scaffolds presenting micro and macropores and pore interconnectivity.

  6. Characterization of the Advanced Stirling Radioisotope Generator Engineering Unit 2

    Science.gov (United States)

    Lewandowski, Edward J.; Oriti, Salvatore M.; Schifer, Niholas A.

    2016-01-01

    Significant progress was made developing the Advanced Stirling Radioisotope Generator (ASRG) 140-W radioisotope power system. While the ASRG flight development project has ended, the hardware that was designed and built under the project is continuing to be tested to support future Stirling-based power system development. NASA Glenn Research Center recently completed the assembly of the ASRG Engineering Unit 2 (EU2). The ASRG EU2 consists of the first pair of Sunpower's Advanced Stirling Convertor E3 (ASC-E3) Stirling convertors mounted in an aluminum housing, and Lockheed Martin's Engineering Development Unit (EDU) 4 controller (a fourth-generation controller). The ASC-E3 convertors and Generator Housing Assembly (GHA) closely match the intended ASRG Qualification Unit flight design. A series of tests were conducted to characterize the EU2, its controller, and the convertors in the flight-like GHA. The GHA contained an argon cover gas for these tests. The tests included measurement of convertor, controller, and generator performance and efficiency; quantification of control authority of the controller; disturbance force measurement with varying piston phase and piston amplitude; and measurement of the effect of spacecraft direct current (DC) bus voltage on EU2 performance. The results of these tests are discussed and summarized, providing a basic understanding of EU2 characteristics and the performance and capability of the EDU 4 controller.

  7. [Current status of bone/cartilage tissue engineering towards clinical applications].

    Science.gov (United States)

    Ohgushi, Hajime

    2014-10-01

    Osteo/chondrogenic differentiation capabilities are seen after in vivo implantation of mesenchymal stem cells (MSCs), which are currently used for the patients having bone/cartilage defects. Importantly, the differentiation capabilities are induced by culturing technology, resulting in in vitro bone/cartilage formation. Especially, the in vitro bone tissue is useful for bone tissue regeneration. For cartilage regeneration, culture expanded chondrocytes derived from patient's normal cartilage are also used for the patients having cartilage damages. Recently, the cultured chondrocytes embedded in atelocollagen gel are obtainable as tissue engineered products distributed by Japan Tissue Engineering Co. Ltd. The products are available in the well-regulated hospitals by qualified orthopedic surgeons. The criteria for these hospitals/surgeons have been established. This review paper focuses on current status of bone/cartilage tissue engineering towards clinical applications in Japan.

  8. The fractal characterization of wear particles in relation to the wear status

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The topography and distribution of wear particles produced in the wear process containmuch information about the wear status. Fractal geometry is applied in this paper to describe thewear particle accumulation in order to characterize the wear status change. The sliding wear test isperformed on a pin-on-disc apparatus using steel disc and brass pin. The investigation resultsshow that wear particle accumulation presents a strong bi-fractal behavior. Also, the fractal dimen-sion varies in correspondence to the wear status change. A new fractal index characterizing thewear particle accumulation is put forward. The wear tests of brass pin demonstrate that the fractalindex is effective in describing the wear status change.

  9. Molecular engineering and characterization of self-assembled biorecognition surfaces

    Science.gov (United States)

    Pan, Sheng

    The development of molecular engineering techniques for the fabrication of biomaterial surfaces is of importance in the field of biomaterials. It offers opportunities for better understanding of biological processes on material surfaces and rational design of contemporary biomaterials. Our work in this area aims to develop novel engineering strategies to design biorecognition surfaces via self-assembly and surface derivatization. Fundamental issues regarding self-assembled monolayer (SAM) structure, formation kinetics, and chemical derivatization were investigated systematically using electron spectroscopy for chemical analysis (ESCA), time-of-flight secondary ion mass spectrometry (TOF-SIMS), infrared reflection absorption spectroscopy (IRAS), atomic force microscopy (AFM), and contact angle measurements. Novel engineering concepts based on multifunctionality and statistical pattern matching were introduced and applied to develop biomimetic surfaces. Our study illustrated that molecules underwent structural transition and orientation development during self-assembly formation, from a disordered, low-density, more liquid-like structure to a highly ordered, closed-packed crystalline-like structure. Surface properties, such as wettability and the reactivity of outermost functional groups can be related to film structure, packing density, as well as molecular orientation. Given the order and organization of SAMs, the accessibility and reactivity of the outermost functional groups, reaction kinetics, stoichiometry, and SAMs stability were studied systematically by surface derivatization of trifluoroacetic anhydride (TFAA). The TFAA derivatization reactions exhibited rapid kinetics on the hydroxyl-terminated SAMs. The data from complementary surface analytical techniques consistently indicated a nearly complete surface reaction. Biomimetic surfaces were made by random immobilization of amino acid of arginine (R), glycine (G), and aspartic acid (D) on well-defined SAMs

  10. Microwell engineering characterization for mammalian cell culture process development.

    Science.gov (United States)

    Barrett, Timothy A; Wu, Andrew; Zhang, Hu; Levy, M Susana; Lye, Gary J

    2010-02-01

    Experimentation in shaken microplate formats offers a potential platform technology for the rapid evaluation and optimization of cell culture conditions. Provided that cell growth and antibody production kinetics are comparable to those found in currently used shake flask systems then the microwell approach offers the possibility to obtain early process design data more cost effectively and with reduced material requirements. This work describes a detailed engineering characterization of liquid mixing and gas-liquid mass transfer in microwell systems and their impact on suspension cell cultures. For growth of murine hybridoma cells producing IgG1, 24-well plates have been characterized in terms of energy dissipation (P/V) (via Computational Fluid Dynamics, CFD), fluid flow, mixing and oxygen transfer rate as a function of shaking frequency and liquid fill volume. Predicted k(L)a values varied between 1.3 and 29 h(-1); liquid-phase mixing time, quantified using iodine decolorization experiments, varied from 1.7 s to 3.5 h; while the predicted P/V ranged from 5 to 35 W m(-3). CFD simulations of the shear rate predicted hydrodynamic forces will not be detrimental to cells. For hybridoma cultures however, high shaking speeds (>250 rpm) were shown to have a negative impact on cell growth, while a combination of low shaking speed and high well fill volume (120 rpm, 2,000 microL) resulted in oxygen limited conditions. Based on these findings a first engineering comparison of cell culture kinetics in microwell and shake flask formats was made at matched average energy dissipation rates. Cell growth kinetics and antibody titer were found to be similar in 24-well microtiter plates and 250 mL shake flasks. Overall this work has demonstrated that cell culture performed in shaken microwell plates can provide data that is both reproducible and comparable to currently used shake flask systems while offering at least a 30-fold decrease in scale of operation and material

  11. Seminar to Discuss the Present Status of Vision Engineering for the Dade County Board of Public Instruction.

    Science.gov (United States)

    Pancoast, Ferendino, Grafton and Skeels, Architects, Miami, FL.

    Proceedings of a seminar on the present status of vision engineering and the possible effects on criteria for school planning. A discussion by Dr. H. Richard Blackwell on vision engineering is included. Topics of discussion include--(1) broad aspects of the effect of light upon sight, (2) lighting variables and task visibility, (3) lighting…

  12. Acoustic Characterization of Compact Jet Engine Simulator Units

    Science.gov (United States)

    Doty, Michael J.; Haskin, Henry H.

    2013-01-01

    Two dual-stream, heated jet, Compact Jet Engine Simulator (CJES) units are designed for wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. The newly fabricated CJES units are characterized with a series of acoustic and flowfield investigations to ensure successful operation with minimal rig noise. To limit simulator size, consistent with a 5.8% HWB model, the CJES units adapt Ultra Compact Combustor (UCC) technology developed at the Air Force Research Laboratory. Stable and controllable operation of the combustor is demonstrated using passive swirl air injection and backpressuring of the combustion chamber. Combustion instability tones are eliminated using nonuniform flow conditioners in conjunction with upstream screens. Through proper flow conditioning, rig noise is reduced by more than 20 dB over a broad spectral range, but it is not completely eliminated at high frequencies. The low-noise chevron nozzle concept designed for the HWB test shows expected acoustic benefits when installed on the CJES unit, and consistency between CJES units is shown to be within 0.5 dB OASPL.

  13. TESTING AND CHARACTERIZATION OF ENGINEERED FORMS OF MONOSODIUM TITANATE (MST)

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K.; Nash, C.; Hobbs, D.

    2012-05-14

    Engineered forms of MST and mMST were prepared at ORNL using an internal gelation process. Samples of these two materials were characterized at SRNL to examine particle size and morphology, peroxide content, tapped densities, and Na, Ti, and C content. Batch contact tests were also performed to examine the performance of the materials. The {sup E}mMST material was found to contain less than 10% of the peroxide found in a freshly prepared batch of mMST. This was also evidenced in batch contact testing with both simulated and actual waste, where little difference in performance was seen between the two engineered materials, {sup E}MST and {sup E}mMST. Based on these results, attempts were made to increase the peroxide content of the materials by post-treatment with hydrogen peroxide. The peroxide treatment resulted in a slight ({approx}10%) increase in peroxide content; however, the peroxide:Ti molar ratio was still much lower ({approx}0.1 X) than what is seen in a freshly prepared batch of mMST. Testing with simulated waste showed the performance of the peroxide treated materials was improved. Batch contact tests were also performed with an earlier (2003) prepared lot of {sup E}MST to examine the effect of ionic strength on the performance of the material. In general the results showed a decrease in removal performance with increasing ionic strength, which is consistent with previous testing with MST. A Sr loading isotherm was also determined, and the {sup E}MST material was found to reach a Sr loading as high as 13.2 wt % after 100 days of contact at a phase ratio of 20000 mL/g. At the typical MST phase ratio of 2500 mL/g (0.4 g/L), a Sr loading of 2.64 wt % was reached after 506 hours of contact. Samples of {sup E}MST and the post-peroxide treated {sup E}mMST were also tested in a column configuration using simulated waste solution. The breakthrough curves along with analysis of the sorbent beds at the conclusion of the experiments showed that the peroxide treated

  14. Cloning, characterization, and engineering of fungal L-arabinitol dehydrogenases.

    Science.gov (United States)

    Kim, Byoungjin; Sullivan, Ryan P; Zhao, Huimin

    2010-07-01

    L-Arabinitol 4-dehydrogenase (LAD) catalyzes the conversion of L-arabinitol to L-xylulose with concomitant NAD(+) reduction in fungal L-arabinose catabolism. It is an important enzyme in the development of recombinant organisms that convert L: -arabinose to fuels and chemicals. Here, we report the cloning, characterization, and engineering of four fungal LADs from Penicillium chrysogenum, Pichia guilliermondii, Aspergillus niger, and Trichoderma longibrachiatum, respectively. The LAD from P. guilliermondii was inactive, while the other three LADs were NAD(+)-dependent and showed high catalytic activities, with P. chrysogenum LAD being the most active. T. longibrachiatum LAD was the most thermally stable and showed the maximum activity in the temperature range of 55-65 degrees C with the other LADs showed the maximum activity in the temperature range of 40-50 degrees C. These LADs were active from pH 7 to 11 with an optimal pH of 9.4. Site-directed mutagenesis was used to alter the cofactor specificity of these LADs. In a T. longibrachiatum LAD mutant, the cofactor preference toward NADP(+) was increased by 2.5 x 10(4)-fold, whereas the cofactor preference toward NADP(+) of the P. chrysogenum and A. niger LAD mutants was also drastically improved, albeit at the expense of significantly reduced catalytic efficiencies. The wild-type LADs and their mutants with altered cofactor specificity could be used to investigate the functionality of the fungal L-arabinose pathways in the development of recombinant organisms for efficient microbial L-arabinose utilization.

  15. Development Status for the Stennis Space Center LIDAR Product Characterization Range

    Science.gov (United States)

    Zanoni, Vicki; Berglund, Judith; Ross, Kenton

    2004-01-01

    The presentation describes efforts to develop a LIDAR in-flight product characterization range at Stennis Space Center as the next phase of the NASA Verification and Validation activities. It describes the status of surveying efforts on targets of interest to LIDAR vendors as well as the potential guidelines that will be used for product characterization.

  16. DebriSat Fragment Characterization System and Processing Status

    Science.gov (United States)

    Rivero, M.; Shiotani, B.; M. Carrasquilla; Fitz-Coy, N.; Liou, J. C.; Sorge, M.; Huynh, T.; Opiela, J.; Krisko, P.; Cowardin, H.

    2016-01-01

    The DebriSat project is a continuing effort sponsored by NASA and DoD to update existing break-up models using data obtained from hypervelocity impact tests performed to simulate on-orbit collisions. After the impact tests, a team at the University of Florida has been working to characterize the fragments in terms of their mass, size, shape, color and material content. The focus of the post-impact effort has been the collection of 2 mm and larger fragments resulting from the hypervelocity impact test. To date, in excess of 125K fragments have been recovered which is approximately 40K more than the 85K fragments predicted by the existing models. While the fragment collection activities continue, there has been a transition to the characterization of the recovered fragments. Since the start of the characterization effort, the focus has been on the use of automation to (i) expedite the fragment characterization process and (ii) minimize the effects of human subjectivity on the results; e.g., automated data entry processes were developed and implemented to minimize errors during transcription of the measurement data. At all steps of the process, however, there is human oversight to ensure the integrity of the data. Additionally, repeatability and reproducibility tests have been developed and implemented to ensure that the instrumentations used in the characterization process are accurate and properly calibrated.

  17. Current status of engineered T-cell therapy for synovial sarcoma.

    Science.gov (United States)

    Dallos, Matthew; Tap, William D; D'Angelo, Sandra P

    2016-09-01

    Synovial sarcoma is a rare soft tissue sarcoma characterized by a t(X;18) translocation, which results in a SYT-SSX gene fusion. In the metastatic setting, chemotherapy has limited, durable efficacy prompting the necessity for new therapeutic modalities. One emerging new strategy involves T-cell-directed therapy such as tumor-infiltrating lymphocytes or the development of T cells that are genetically engineered to express a T-cell receptor against a cancer testis antigen. Of these approaches, engineered T cells that recognize NY-ESO-1 are the furthest along in development. Completed and on-going clinical trials have shown promise and there are efforts to continue to optimize the current approach.

  18. Processing and characterization of piezoelectric polymers for tissue engineering applications

    OpenAIRE

    Ribeiro, Clarisse Marta Oliveira

    2012-01-01

    Tese de doutoramento em Ciências (ramo de conhecimento em Física) In the last decades, the biomaterials and tissue engineering interdisciplinary research fields have been two of the most dynamic ones and have attracted increasing attention by the scientific community. With the advancements in the tissue engineering field the necessity of study and develop a wide variety of biomaterials with different properties has emerged. Among the different types of materials, polymers hav...

  19. Los Alamos National Laboratory Yucca Mountain Site Characterization Project 1994 quality program status report

    Energy Technology Data Exchange (ETDEWEB)

    Bolivar, S.L.

    1996-03-01

    This status report is for calendar year 1994. It summarizes the annual activities and accomplishments of the Los Alamos National Laboratory Yucca Mountain Site Characterization Project (YMP or Project) quality assurance program. By identifying the accomplishments of the quality program, a baseline is established that will assist in decision making, improve administrative controls and predictability, and allow us to annually identify adverse trends and to evaluate improvements. This is the fourth annual status report.

  20. Engineering status of the superconducting end cap toroid magnets for the ATLAS experiment at LHC

    CERN Document Server

    Baynham, D Elwyn; Carr, F S; Courthold, M J D; Cragg, D A; Densham, C J; Evans, D; Holtom, E; Rochford, J; Sole, D; Towndrow, Edwin F; Warner, G P

    2000-01-01

    The ATLAS experiment at LHC, CERN will utilise a large, superconducting, air-cored toroid magnet system for precision muon measurements. The magnet system will consist of a long barrel and two end-cap toroids. Each end-cap toroid will contain eight racetrack coils mounted as a single cold mass in cryostat vessel of ~10 m diameter. The project has now moved from the design/specification stage into the fabrication phase. This paper presents the engineering status of the cold masses and vacuum vessels that are under fabrication in industry. Final designs of cold mass supports, cryogenic systems and control/protection systems are presented. Planning for toroid integration, test and installation is described. (3 refs).

  1. Characterization of electrical stimulation electrodes for cardiac tissue engineering.

    Science.gov (United States)

    Tandon, Nina; Cannizzaro, Chris; Figallo, Elisa; Voldman, Joel; Vunjak-Novakovic, Gordana

    2006-01-01

    Electrical stimulation has been shown to improve functional assembly of cardiomyocytes in vitro for cardiac tissue engineering. The goal of this study was to assess the conditions of electrical stimulation with respect to the electrode geometry, material properties and charge-transfer characteristics at the electrode-electrolyte interface. We compared various biocompatible materials, including nanoporous carbon, stainless steel, titanium and titanium nitride, for use in cardiac tissue engineering bioreactors. The faradaic and non-faradaic charge transfer mechanisms were assessed by electrochemical impedance spectroscopy (EIS), studying current injection characteristics, and examining surface properties of electrodes with scanning electron microscopy. Carbon electrodes were found to have the best current injection characteristics. However, these electrodes require careful handling because of their limited mechanical strength. The efficacy of various electrodes for use in 2-D and 3-D cardiac tissue engineering systems with neonatal rat cardiomyocytes is being determined by assessing cell viability, amplitude of contractions, excitation thresholds, maximum capture rate, and tissue morphology.

  2. Characterizing Distributed Concurrent Engineering Teams: A Descriptive Framework for Aerospace Concurrent Engineering Design Teams

    Science.gov (United States)

    Chattopadhyay, Debarati; Hihn, Jairus; Warfield, Keith

    2011-01-01

    As aerospace missions grow larger and more technically complex in the face of ever tighter budgets, it will become increasingly important to use concurrent engineering methods in the development of early conceptual designs because of their ability to facilitate rapid assessments and trades in a cost-efficient manner. To successfully accomplish these complex missions with limited funding, it is also essential to effectively leverage the strengths of individuals and teams across government, industry, academia, and international agencies by increased cooperation between organizations. As a result, the existing concurrent engineering teams will need to increasingly engage in distributed collaborative concurrent design. This paper is an extension of a recent white paper written by the Concurrent Engineering Working Group, which details the unique challenges of distributed collaborative concurrent engineering. This paper includes a short history of aerospace concurrent engineering, and defines the terms 'concurrent', 'collaborative' and 'distributed' in the context of aerospace concurrent engineering. In addition, a model for the levels of complexity of concurrent engineering teams is presented to provide a way to conceptualize information and data flow within these types of teams.

  3. Los Alamos National Laboratory Yucca Mountain Site Characterization Project 1995 quality program status report

    Energy Technology Data Exchange (ETDEWEB)

    Bolivar, S.L.

    1996-07-01

    This status report summarizes the activities and accomplishments of the Los Alamos National Laboratory Yucca Mountain Site Characterization Project`s (YMP`s) quality assurance program for January 1 to September 30, 1995. The report includes major sections on program activities and trend analysis.

  4. Characterization of hair follicle development in engineered skin substitutes.

    Directory of Open Access Journals (Sweden)

    Penkanok Sriwiriyanont

    Full Text Available Generation of skin appendages in engineered skin substitutes has been limited by lack of trichogenic potency in cultured postnatal cells. To investigate the feasibility and the limitation of hair regeneration, engineered skin substitutes were prepared with chimeric populations of cultured human keratinocytes from neonatal foreskins and cultured murine dermal papilla cells from adult GFP transgenic mice and grafted orthotopically to full-thickness wounds on athymic mice. Non-cultured dissociated neonatal murine-only skin cells, or cultured human-only skin keratinocytes and fibroblasts without dermal papilla cells served as positive and negative controls respectively. In this study, neonatal murine-only skin substitutes formed external hairs and sebaceous glands, chimeric skin substitutes formed pigmented hairs without sebaceous glands, and human-only skin substitutes formed no follicles or glands. Although chimeric hair cannot erupt readily, removal of upper skin layer exposed keratinized hair shafts at the skin surface. Development of incomplete pilosebaceous units in chimeric hair corresponded with upregulation of hair-related genes, LEF1 and WNT10B, and downregulation of a marker of sebaceous glands, Steroyl-CoA desaturase. Transepidermal water loss was normal in all conditions. This study demonstrated that while sebaceous glands may be involved in hair eruption, they are not required for hair development in engineered skin substitutes.

  5. Curiosity’s robotic arm-mounted Mars Hand Lens Imager (MAHLI): Characterization and calibration status

    Science.gov (United States)

    Edgett, Kenneth S.; Caplinger, Michael A.; Maki, Justin N.; Ravine, Michael A.; Ghaemi, F. Tony; McNair, Sean; Herkenhoff, Kenneth E.; Duston, Brian M.; Wilson, Reg G.; Yingst, R. Aileen; Kennedy, Megan R.; Minitti, Michelle E.; Sengstacken, Aaron J.; Supulver, Kimberley D.; Lipkaman, Leslie J.; Krezoski, Gillian M.; McBride, Marie J.; Jones, Tessa L.; Nixon, Brian E.; Van Beek, Jason K.; Krysak, Daniel J.; Kirk, Randolph L.

    2015-01-01

    MAHLI (Mars Hand Lens Imager) is a 2-megapixel, Bayer pattern color CCD camera with a macro lens mounted on a rotatable turret at the end of the 2-meters-long robotic arm aboard the Mars Science Laboratory rover, Curiosity. The camera includes white and longwave ultraviolet LEDs to illuminate targets at night. Onboard data processing services include focus stack merging and data compression. Here we report on the results and status of MAHLI characterization and calibration, covering the pre-launch period from August 2008 through the early months of the extended surface mission through February 2015. Since landing in Gale crater in August 2012, MAHLI has been used for a wide range of science and engineering applications, including distinction among a variety of mafic, siliciclastic sedimentary rocks; investigation of grain-scale rock, regolith, and eolian sediment textures and structures; imaging of the landscape; inspection and monitoring of rover and science instrument hardware concerns; and supporting geologic sample selection, extraction, analysis, delivery, and documentation. The camera has a dust cover and focus mechanism actuated by a single stepper motor. The transparent cover was coated with a thin film of dust during landing, thus MAHLI is usually operated with the cover open. The camera focuses over a range from a working distance of 2.04 cm to infinity; the highest resolution images are at 13.9 µm per pixel; images acquired from 6.9 cm show features at the same scale as the Mars Exploration Rover Microscopic Imagers at 31 µm/pixel; and 100 µm/pixel is achieved at a working distance of ~26.5 cm. The very highest resolution images returned from Mars permit distinction of high contrast silt grains in the 30–40 µm size range. MAHLI has performed well; the images need no calibration in order to achieve most of the investigation’s science and engineering goals. The positioning and repeatability of robotic arm placement of the MAHLI camera head have

  6. Characterization of coal-water slurry fuel sprays from diesel engine injectors

    Energy Technology Data Exchange (ETDEWEB)

    Caton, J.A.; Kihm, K.D.

    1993-06-01

    Experiments were conducted to characterize coal-water slurry fuel sprays from diesel engine injectors. Since the combustion event is a strong function of the fuel spray, full characterization of the spray is a necessity for successful engine design and for modeling of the combustion process. Two experimental facilities were used at TAMU to study the injection of coal slurry fuels. The first experimental facility incorporates General Electric locomotive engine components (injection pump, fuel line, and nozzle) and a specially designed diaphragm to separate the abrasive coal slurry fuel from the moving parts of the pump. The second experimental facility is based on an accumulator injector from General Electric. Instrumentation includes instantaneous needle lift and fuel line pressure. A pressurized visualization chamber was used to provide a spray environment which simulated the engine gas density and permitted the use of spray diagnostic techniques. The study was divided into two phases: (1) overall characterization of the spray, and (2) detailed droplet size and size distribution characterization. In addition to this overall characterization of the spray, the second phase of this study characterized the details of the atomization quality.

  7. Eliciting and characterizing students' mental models within the context of engineering design

    Science.gov (United States)

    Dankenbring, Chelsey

    Recently, science education reform documents have called for the incorporation of engineering principles and practices into the K-12 science standards and curriculum. One way this has been done is through the use of engineering design tasks as a way for students to apply their scientific understandings to real-world problems. However, minimal studies have documented students' conceptions within the context of engineering design. Thus, the first chapter of this thesis outlines the steps taken to develop a draw-and-explain item that elicited students' mental models regarding the cause of the four seasons after finishing an engineering design task. Students' mental models regarding the reason for the seasons are also described. The second chapter characterizes students' conceptions regarding sun-Earth relationships, specifically the amount of daylight hours throughout the year, for students who completed either an engineering design task or more traditional learning activities. Results from these studies indicate that draw-and-explain items are an effective way of obtaining students' mental models and that students harbor a variety of alternate conceptions on astronomy related concepts within various learning contexts. Implications from this study include the need for further research regarding how engineering design is used in the classroom and how engineering design facilitates science learning. Also, professional development that allows in-service teachers to gain experience teaching engineering design is needed, as are teacher preparation programs that expose pre-service teachers to engineering design.

  8. Thermal Characterization of Nanostructures and Advanced Engineered Materials

    Science.gov (United States)

    Goyal, Vivek Kumar

    Continuous downscaling of Si complementary metal-oxide semiconductor (CMOS) technology and progress in high-power electronics demand more efficient heat removal techniques to handle the increasing power density and rising temperature of hot spots. For this reason, it is important to investigate thermal properties of materials at nanometer scale and identify materials with the extremely large or extremely low thermal conductivity for applications as heat spreaders or heat insulators in the next generation of integrated circuits. The thin films used in microelectronic and photonic devices need to have high thermal conductivity in order to transfer the dissipated power to heat sinks more effectively. On the other hand, thermoelectric devices call for materials or structures with low thermal conductivity because the performance of thermoelectric devices is determined by the figure of merit Z=S2sigma/K, where S is the Seebeck coefficient, K and sigma are the thermal and electrical conductivity, respectively. Nanostructured superlattices can have drastically reduced thermal conductivity as compared to their bulk counterparts making them promising candidates for high-efficiency thermoelectric materials. Other applications calling for thin films with low thermal conductivity value are high-temperature coatings for engines. Thus, materials with both high thermal conductivity and low thermal conductivity are technologically important. The increasing temperature of the hot spots in state-of-the-art chips stimulates the search for innovative methods for heat removal. One promising approach is to incorporate materials, which have high thermal conductivity into the chip design. Two suitable candidates for such applications are diamond and graphene. Another approach is to integrate the high-efficiency thermoelectric elements for on-spot cooling. In addition, there is strong motivation for improved thermal interface materials (TIMs) for heat transfer from the heat-generating chip

  9. Characterization of human myoblast cultures for tissue engineering.

    Science.gov (United States)

    Stern-Straeter, Jens; Bran, Gregor; Riedel, Frank; Sauter, Alexander; Hörmann, Karl; Goessler, Ulrich Reinhart

    2008-01-01

    Skeletal muscle tissue engineering, a promising specialty, aims at the reconstruction of skeletal muscle loss. In vitro tissue engineering attempts to achieve this goal by creating differentiated, functional muscle tissue through a process in which stem cells are extracted from the patient, e.g. by muscle biopsies, expanded and differentiated in a controlled environment, and subsequently re-implanted. A prerequisite for this undertaking is the ability to cultivate and differentiate human skeletal muscle cell cultures. Evidently, optimal culture conditions must be investigated for later clinical utilization. We therefore analysed the proliferation of human cells in different environments and evaluated the differentiation potential of different culture media. It was shown that human myoblasts have a higher rate of proliferation in the alamarBlue assay when cultured on gelatin-coated culture flasks rather than polystyrene-coated flasks. We also demonstrated that myoblasts treated with a culture medium with a high concentration of growth factors [growth medium (GM)] showed a higher proliferation compared to cultures treated with a culture medium with lower amounts of growth factors [differentiation medium (DM)]. Differentiation of human myoblast cell cultures treated with GM and DM was analysed until day 16 and myogenesis was verified by expression of MyoD, myogenin, alpha-sarcomeric actin and myosin heavy chain by semi-quantitative RT-PCR. Immunohistochemical staining for desmin, Myf-5 and alpha-sarcomeric actin was performed to verify the myogenic phenotype of extracted satellite cells and to prove the maturation of cells. Cultures treated with DM showed positive staining for alpha-sarcomeric actin. Notably, markers of differentiation were also detected in cultures treated with GM, but there was no formation of myotubes. In the enzymatic assay of creatine phosphokinase, cultures treated with DM showed a higher activity, evidencing a higher degree of differentiation

  10. Engineered Materials Characterization Report for the Yucca Mountain Site Characterization Project, Volume 3, Revision 1, Corrosion Data and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    McCright, R D

    1998-04-01

    The Engineered Materials Characterization Report (EMCR) serves as a source of information on the properties of materials proposed as elements in the engineered barrier system (EBS) for the Yucca Mountain nuclear waste repository. Volume 3 covered the corrosion data and modeling efforts. The present report is a revision to Volume 3 and updates information on the corrosion (and other degradation modes) behavior of candidate materials for the various components of the EBS. It also includes work on the performance modeling of these materials. Work is reported on metallic barriers, basket materials, packing/backfill/invert materials, and non-metallic materials.

  11. Ultrasound Imaging Techniques for Spatiotemporal Characterization of Composition, Microstructure, and Mechanical Properties in Tissue Engineering.

    Science.gov (United States)

    Deng, Cheri X; Hong, Xiaowei; Stegemann, Jan P

    2016-08-01

    Ultrasound techniques are increasingly being used to quantitatively characterize both native and engineered tissues. This review provides an overview and selected examples of the main techniques used in these applications. Grayscale imaging has been used to characterize extracellular matrix deposition, and quantitative ultrasound imaging based on the integrated backscatter coefficient has been applied to estimating cell concentrations and matrix morphology in tissue engineering. Spectral analysis has been employed to characterize the concentration and spatial distribution of mineral particles in a construct, as well as to monitor mineral deposition by cells over time. Ultrasound techniques have also been used to measure the mechanical properties of native and engineered tissues. Conventional ultrasound elasticity imaging and acoustic radiation force imaging have been applied to detect regions of altered stiffness within tissues. Sonorheometry and monitoring of steady-state excitation and recovery have been used to characterize viscoelastic properties of tissue using a single transducer to both deform and image the sample. Dual-mode ultrasound elastography uses separate ultrasound transducers to produce a more potent deformation force to microscale characterization of viscoelasticity of hydrogel constructs. These ultrasound-based techniques have high potential to impact the field of tissue engineering as they are further developed and their range of applications expands.

  12. Life Finder Detectors; Detector Needs and Status for Spectroscopic Biosignature Characterization

    Science.gov (United States)

    Rauscher, Bernard J.; Bolcar, Matthew R.; Clampin, Mark; Domagal-Goldman, Shawn; McElwain, Michael W.; Moseley, Samuel H.; Stahle, Carl; Stark, Christopher C.; Thronson, Harley A.

    2016-01-01

    The search for life on other worlds looms large in NASA's future. Outside our solar system, direct spectroscopic biosignature characterization using very large UV-Optical-IR telescopes with coronagraphs or starshades is a core technique to both AURA's High Definition Space Telescope (HDST) concept and NASA's 30-year strategic plan. These giant space observatories require technological advancements in several areas, one of which is detectors. In this presentation, we review the detector requirements for spectroscopic biosignature characterization and discuss the status of some existing and proposed detector technologies for meeting them.

  13. 76 FR 8707 - Syngenta Seeds, Inc.; Determination of Nonregulated Status for Corn Genetically Engineered To...

    Science.gov (United States)

    2011-02-15

    ..., ``Introduction of Organisms and Products Altered or Produced Through Genetic Engineering Which Are Plant Pests or... produced through genetic engineering that are plant pests or that there is reason to believe are...

  14. Engineering of Carbon Nanotube Actuators and Tools for Their Characterization

    Science.gov (United States)

    Kozlov, Mikhail; Chang, Heping; Cui, Changxing; Liu, Lo-Min; Morris, Bob; Spinks, Geoff; Khayrullin, Ilyas; Zakhidov, Anvar; Iqbal, Zafar; Baughman, Ray

    2000-03-01

    We report comparative data on electromechanical response as a function of voltage for carbon actuators based on single-wall and multi-wall nanotubes, graphite and nanotube-polymer composites. The measurements were carried out in aqueous NaCl electrolyte, under variable load, in broad voltage and temperature ranges. A specially designed tensile tester provided isometric conditions for sample characterization. Data on stress-strain generation, elastic constants, and thermal expansion was obtained from our apparatus. Measurements show that isometric stress generation in an actuator based on low-surface- area graphite is less than 0.01 MPa, whereas for single-wall nanotubes this stress readily exceeds 0.7 MPa. Experimental data are compared with predictions for the dimensional changes in carbon nanotubes caused by charge injection and temperature variation. Tensile, cantilever and helical actuation mechanisms in single-wall nanotubes are discussed.

  15. Physico-chemical characterization of collagen scaffolds for tissue engineering

    Directory of Open Access Journals (Sweden)

    B.H. León-Mancilla

    2016-02-01

    Full Text Available The objective was to research the physical and chemical properties of collagen scaffolds (CS obtained from bone matrix Nukbone® subject to a demineralization process using hydrochloric acid. The CS samples were characterized by optical and scanning electron microscopy, elemental chemical analysis, X-ray diffraction, spectroscopy Infrared, thermal analysis, differential scanning calorimetry and nitrogen adsorption. The microanalysis were used to set the macro- and microstructures of CS. They showed that the CS retained the morphology of Nukbone® with interconnected pores and their size between 100 and 500 μm, and it is composed of 20% by weight of HA and the rest is collagen type I. By infrared spectroscopy the functional groups of collagen type I (amide A – 3285, B – 2917, I – 1633, II – 1553 and III – 1239 cm−1 were identified. By thermal analysis it was determined that the phenomenon of denaturation of the collagen type I began in the range of 75–85 °C and burned above 200 °C.

  16. Diesel engine technology `98. Status and trends; Dieselmotorentechnik 98. Aktueller Stand und Entwicklungstendenzen

    Energy Technology Data Exchange (ETDEWEB)

    Essers, U. [ed.] [Stuttgart Univ. (Germany)

    1998-09-01

    This book reviews important aspects of modern diesel engines. Renowned university scientists and competent experts from the car and components industry present trends in diesel engineering. The current state of the art is outlined, and the potential and solutions for future requirements are outlined. Contents: Direct injection in diesel engines - radial piston injection pumps for modern diesel engines in passenger cars - common rail injection - electronic control of diesel engines - supercharging of diesel engines - direct-injection diesel engines with supercharger - aldehyde emissions of diesel engines - exhaust regulations for industrial vehicles - combustion diagnosis in diesel engines - soot formation - direct-injection diesel engines and spark ignition engines - trends in passenger car development. (orig.) [Deutsch] Der Band beleuchtet wichtige Aspekte der modernen Dieselmotoren. Namhafte Wissenschaftler von verschiedenen Hochschulen und kompetente Fachexperten aus der Fahrzeug- und Zubehoerindustrie berichten ueber Entwicklungstendenzen auf dem Gebiet der Dieselmotorentechnik. Der aktuelle Stand der Entwicklung wird aufgezeigt. Potential und Loesungsansaetze fuer kuenftige Anforderungen werden diskutiert. Inhalt: Direkteinspritzung bei Dieselmotoren - Radialkolben-Verteilereinspritzpumpen fuer moderne Pkw-DI-Dieselmotoren - Common Rail-Einspritzung - Elektronische Dieselregelung - Aufladung von Dieselmotoren - Pkw-DI-Dieselmotor mit VTG-Lader - Aldehydemission von Dieselmotoren - Abgasgesetzgebung fuer Nfz-Dieselmotoren - Verbrennungsdiagnostik im Dieselmotor - Russbildung - DI-Dieselmotor und DI-Ottomotor - Wohin geht die PkW-Motorentwicklung? (orig.)

  17. Motivation, characterization, and strategy for tissue engineering the temporomandibular joint disc.

    Science.gov (United States)

    Detamore, Michael S; Athanasiou, Kyriacos A

    2003-12-01

    The purpose of this review is to serve as the standard point of reference in guiding researchers investigating the tissue engineering of the temporomandibular joint (TMJ) disc. Tissue engineering of the TMJ disc is in its infancy, and currently there exists a gap between the tissue engineering community and the TMJ characterization community. The primary goal is to help bridge that gap by consolidating the characterization studies here as a reference to researchers attempting to tissue engineer the TMJ disc. A brief review of TMJ anatomy is provided, along with a description of relevant pathology, current treatment, and a rationale for engineering the TMJ disc. The biochemical composition and organization of the disc are reviewed, including glycosaminoglycan (GAG) and collagen content. The collagen of the disc is almost exclusively type I and primarily runs anteroposteriorly through the center and in a ringlike fashion around the periphery. The GAG content is approximately an order of magnitude less than that of hyaline cartilage, and although the distribution is not entirely clear, it seems as though chondroitin and dermatan sulfate are by far the primary GAGs. Cellular characterization and mechanical properties under compression, tension, and shear are reviewed as well. The cells of the disc are not chondrocytes, but rather resemble fibrocytes and fibrochondrocytes and may be of the same lineage. Mechanically, the disc is certainly anisotropic and nonhomogeneous. Finally, a review of efforts in tissue engineering and cell culture studies of the disc is provided and we close with a description of the direction we envision/propose for successful tissue engineering of the TMJ disc.

  18. Experimental characterization of a small custom-built double-acting gamma-type stirling engine

    Science.gov (United States)

    Intsiful, Peter; Mensah, Francis; Thorpe, Arthur

    This paper investigates characterization of a small custom-built double-acting gamma-type stirling engine. Stirling-cycle engine is a reciprocating energy conversion machine with working spaces operating under conditions of oscillating pressure and flow. These conditions may be due to compressibility as wells as pressure and temperature fluctuations. In standard literature, research indicates that there is lack of basic physics to account for the transport phenomena that manifest themselves in the working spaces of reciprocating engines. Previous techniques involve governing equations: mass, momentum and energy. Some authors use engineering thermodynamics. None of these approaches addresses this particular engine. A technique for observing and analyzing the behavior of this engine via parametric spectral profiles has been developed, using laser beams. These profiles enabled the generation of pv-curves and other trajectories for investigating the thermos-physical and thermos-hydrodynamic phenomena that manifest in the exchangers. The engine's performance was examined. The results indicate that with current load of 35.78A, electric power of 0.505 kW was generated at a speed of 240 rpm and 29.50 percent efficiency was obtained. Nasa grants to Howard University NASA/HBCU-NHRETU & CSTEA.

  19. Status, Vision, and Challenges of an Intelligent Distributed Engine Control Architecture

    Science.gov (United States)

    Behbahani, Alireza; Culley, Dennis; Garg, Sanjay; Millar, Richard; Smith, Bert; Wood, Jim; Mahoney, Tim; Quinn, Ronald; Carpenter, Sheldon; Mailander, Bill; Battestin, Gary; Roney, Walter; Bluish, Colin; Rhoden, William; Storey, Bill

    2007-01-01

    A Distributed Engine Control Working Group (DECWG) consisting of the Department of Defense (DoD), the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) and industry has been formed to examine the current and future requirements of propulsion engine systems. The scope of this study will include an assessment of the paradigm shift from centralized engine control architecture to an architecture based on distributed control utilizing open system standards. Included will be a description of the work begun in the 1990's, which continues today, followed by the identification of the remaining technical challenges which present barriers to on-engine distributed control.

  20. 78 FR 13302 - Syngenta Biotechnology, Inc.; Determination of Nonregulated Status of Corn Genetically Engineered...

    Science.gov (United States)

    2013-02-27

    ... Products Altered or Produced Through Genetic Engineering Which Are Plant Pests or Which There Is Reason to... movement, or release into the environment) of organisms and products altered or produced through genetic engineering that are plant pests or that there is reason to believe are plant pests. Such...

  1. Characterizing learning-through-service students in engineering by gender and academic year

    Science.gov (United States)

    Carberry, Adam Robert

    Service is increasingly being viewed as an integral part of education nationwide. Service-based courses and programs are growing in popularity as opportunities for students to learn and experience their discipline. Widespread adoption of learning-through-service (LTS) in engineering is stymied by a lack of a body of rigorous research supporting the effectiveness of these experiences. In this study, I examine learning-through-service through a nationwide survey of engineering undergraduate and graduate students participating in a variety of LTS experiences. Students (N = 322) participating in some form of service -- service-learning courses or extra-curricular service programs -- from eighty-seven different institutions across the United States completed a survey measuring demographic information (institution, gender, academic year, age, major, and grade point average), self-perceived sources of learning (service and traditional coursework), engineering epistemological beliefs, personality traits, and self-concepts (self-efficacy, motivation, expectancy, and anxiety) toward engineering design. Responses to the survey were used to characterize engineering LTS students and identify differences in these variables in terms of gender and academic year. The overall findings were that LTS students perceived their service experience to be a beneficial source for learning professional skills and, to a lesser degree, technical skills, held moderately sophisticated engineering epistemological beliefs, and were generally outgoing, compassionate, and adventurous. Self-perceived sources of learning, epistemological beliefs, and personality traits were shown to be poor predictors of student engineering achievement. Self-efficacy, motivation, and outcome expectancy toward engineering design were generally high for all LTS students; most possessed rather low anxiety levels toward engineering design. These trends were generally consistent between genders and across the five academic

  2. FY 93 site characterization status report and data package for the carbon tetrachloride site

    Energy Technology Data Exchange (ETDEWEB)

    Rohay, V.J. [Westinghouse Hanford Co., Richland, WA (United States)

    1993-09-28

    This report provides the status and accomplishments from fiscal year site characterization activities conducted as part of the 200 West Area Carbon Tetrachloride Expedited Response Action and the Volatile Organic Compounds - Arid Integrated Demonstration. The report includes or references all available raw data collected as part of these tasks. During fiscal year 1993, the 200 West Area Carbon Tetrachloride Expedited Response Action and the Volatile Organic Compounds - Arid Integrated Demonstration programs focused on the carbon tetrachloride plume in the unsaturated zone underlying the 200 West Area at the Hanford Site in southeast Washington.

  3. The Status of Technology and Engineering Education in the United States: A Fourth Report of the Findings from the States (2011-12)

    Science.gov (United States)

    Moye, Johnny J.; Dugger, William E., Jr.; Starkweather, Kendall N.

    2012-01-01

    Technology and engineering education continues to evolve as it becomes more apparent that students need this information to become more successful in college and careers. The International Technology and Engineering Educators Association (ITEEA ) has tracked the status of technology education in the United States in three separate studies over the…

  4. Analysis of Uncertainty and Variability in Finite Element Computational Models for Biomedical Engineering: Characterization and Propagation.

    Science.gov (United States)

    Mangado, Nerea; Piella, Gemma; Noailly, Jérôme; Pons-Prats, Jordi; Ballester, Miguel Ángel González

    2016-01-01

    Computational modeling has become a powerful tool in biomedical engineering thanks to its potential to simulate coupled systems. However, real parameters are usually not accurately known, and variability is inherent in living organisms. To cope with this, probabilistic tools, statistical analysis and stochastic approaches have been used. This article aims to review the analysis of uncertainty and variability in the context of finite element modeling in biomedical engineering. Characterization techniques and propagation methods are presented, as well as examples of their applications in biomedical finite element simulations. Uncertainty propagation methods, both non-intrusive and intrusive, are described. Finally, pros and cons of the different approaches and their use in the scientific community are presented. This leads us to identify future directions for research and methodological development of uncertainty modeling in biomedical engineering.

  5. Characterizing Design Process Interfaces as Organization Networks: Insights for Engineering Systems Management

    DEFF Research Database (Denmark)

    Ruiz, Pedro Parraguez; Eppinger, Steven; Maier, Anja

    2016-01-01

    and interpret the effect of those characteristics on interface problems. As a result, we show how structural and compositional aspects of the organization networks between information-dependent activities provide valuable insights to better manage complex engineering design processes. The proposed approach...... is applied to the development of a power plant, analyzing 79 process interfaces. The study reveals a relationship between the structure and composition of the process interfaces and reported interface problems. Implications of this approach include the integration of information about process......The engineering design literature has provided guidance on how to identify and analyze design activities and their information dependencies. However, a systematic characterization of process interfaces between engineering design activities is missing, and the impact of structural and compositional...

  6. Status of Testing and Characterization of CMS Alloy 617 and Alloy 230

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Santella, Michael L [ORNL; Battiste, Rick [ORNL; Terry, Totemeier [Idaho National Laboratory (INL); Denis, Clark [Idaho National Laboratory (INL)

    2006-08-01

    Status and progress in testing and characterizing CMS Alloy 617 and Alloy 230 tasks in FY06 at ORNL and INL are described. ORNL research has focused on CMS Alloy 617 development and creep and tensile properties of both alloys. In addition to refurbishing facilities to conduct tests, a significant amount of creep and tensile data on Alloy 230, worth several years of research funds and time, has been located and collected from private enterprise. INL research has focused on the creep-fatigue behavior of standard chemistry Alloy 617 base metal and fusion weldments. Creep-fatigue tests have been performed in air, vacuum, and purified Ar environments at 800 and 1000 C. Initial characterization and high-temperature joining work has also been performed on Alloy 230 and CCA Alloy 617 in preparation for creep-fatigue testing.

  7. Low-Temperature Performance of Chinese Automotive Engine Oils-Status and Perspectives

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Performance of automotive engine oils at low temperature has been extensively investigated in the last 50 years. The resulting understanding of engine oil rheology has been used to devise bench tests that predict their performance under cold starting conditions. Cold starting the engine has been essentially overcome for passenger car engines with fuel injection but pumpability of the engine oil has grown more demanding. Two tests (MRV TP1 and the Scanning Brookfield Technique with Gelation Index measurement) have become the measures of quality in pumpability response at low temperatures. As such they have become ASTM Methods and are included in a number of international specifications such as SAE J300 and ILSAC/API GF-1, 2, 3, and 4 accompanied by appropriate limits.For a number of years, the Institute of Materials (IOM) has generated a database for Asia-Pacific engine oils for IOM Subscribers. This database can be used to assess and compare the performance of Chinese engine oils at low temperature to one another and to the larger world of engine oils also covered by the IOM database. This IOM survey of Asia-Pacific provides a complete 36-test analysis of 300 passenger car engine oils from the region including a wide range of chemical analysis, rheological measurements and performance assessments. In this paper we concentrate on the low temperature analysis of the rheology of samples collected in China since 2000.The important factors affecting formulation of engine oils in China today are:1. The recent inclusion of the MRV TP-1 and Scanning Brookfield Gelation Index requirements in China's National Standards for engine oil quality; 2. The availability of higher quality oils; 3. The higher treat rate of additives will require increased attention from the formulators in the selection of VI Improvers and Pour Point Depressants (PPDs). In the latter case, new PPDs are likely to be required to provide formulators with robust and economical solutions to face these new

  8. Multi-scale mechanical characterization of scaffolds for heart valve tissue engineering.

    Science.gov (United States)

    Argento, G; Simonet, M; Oomens, C W J; Baaijens, F P T

    2012-11-15

    Electrospinning is a promising technology to produce scaffolds for cardiovascular tissue engineering. Each electrospun scaffold is characterized by a complex micro-scale structure that is responsible for its macroscopic mechanical behavior. In this study, we focus on the development and the validation of a computational micro-scale model that takes into account the structural features of the electrospun material, and is suitable for studying the multi-scale scaffold mechanics. We show that the computational tool developed is able to describe and predict the mechanical behavior of electrospun scaffolds characterized by different microstructures. Moreover, we explore the global mechanical properties of valve-shaped scaffolds with different microstructural features, and compare the deformation of these scaffolds when submitted to diastolic pressures with a tissue engineered and a native valve. It is shown that a pronounced degree of anisotropy is necessary to reproduce the deformation patterns observed in the native heart valve.

  9. The Design and Research of the Operation Status Detector for Marine Engine Room Power Plant Based on Noise

    Directory of Open Access Journals (Sweden)

    Li Hang

    2016-01-01

    Full Text Available Designed in this paper, based on the noise of ship engine room power plant running status of detector, is mainly used in the operation of the power plant of acoustic shell size to determine when the machine running state, this device is composed of signal disposal and alarm display adjustment part of two parts. Detector that can show the size of the voice, if exceed the set limit alarm value, the detector can sound an alarm, to remind staff equipment fails, it shall timely inspection maintenance, improve the safety of the operation of the ship.

  10. Emerging Microfluidic Tools for Functional Cellular Immunophenotyping: A New Potential Paradigm for Immune Status Characterization

    Directory of Open Access Journals (Sweden)

    Weiqiang eChen

    2013-04-01

    Full Text Available Rapid, accurate, and quantitative characterization of immune status of patients is of utmost importance for disease diagnosis and prognosis, evaluating efficacy of immunotherapeutics and tailoring drug treatments. Immune status of patients is often dynamic and patient-specific, and such complex heterogeneity has made accurate, real-time measurements of patient immune status challenging in the clinical setting. Recent advances in microfluidics have demonstrated promising applications of microfluidics for immune monitoring with minimum sample requirement and rapid functional immunophenotyping capability. This review will highlight recent developments of microfluidic platforms that can perform rapid and accurate cellular functional assays on patient immune cells. We will also discuss the future potential of integrated microfluidics to perform rapid, accurate, and sensitive cellular functional assays at a single-cell resolution on different types or subpopulations of immune cells, to provide an unprecedented level of information depth on the distribution of immune cell functionalities. We envision that such microfluidic immunophenotyping tools will allow comprehensive and systems-level immunomonitoring, unlocking the potential to transform experimental clinical immunology into an information-rich science.

  11. Latest status of the clinical and industrial applications of cell sheet engineering and regenerative medicine.

    Science.gov (United States)

    Egami, Mime; Haraguchi, Yuji; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

    2014-01-01

    Cell sheet engineering, which allows tissue engineering to be realized without the use of biodegradable scaffolds as an original approach, using a temperature-responsive intelligent surface, has been applied in regenerative medicine for various tissues, and a number of clinical studies have been already performed for life-threatening diseases. By using the results and findings obtained from the initial clinical studies, additional investigative clinical studies in several tissues with cell sheet engineering are currently in preparation stage. For treating many patients effectively by cell sheet engineering, an automated system integrating cell culture, cell-sheet fabrication, and layering is essential, and the system should include an advanced three-dimensional suspension cell culture system and an in vitro bioreactor system to scale up the production of cultured cells and fabricate thicker vascularized tissues. In this paper, cell sheet engineering, its clinical application, and further the authors' challenge to develop innovative cell culture systems under newly legislated regulatory platform in Japan are summarized and discussed.

  12. Spatiotemporal Characterization of Extracellular Matrix Microstructures in Engineered Tissue: A Whole-Field Spectroscopic Imaging Approach.

    Science.gov (United States)

    Xu, Zhengbin; Ozcelikkale, Altug; Kim, Young L; Han, Bumsoo

    2013-02-01

    Quality and functionality of engineered tissues are closely related to the microstructures and integrity of their extracellular matrix (ECM). However, currently available methods for characterizing ECM structures are often labor-intensive, destructive, and limited to a small fraction of the total area. These methods are also inappropriate for assessing temporal variations in ECM structures. In this study, to overcome these limitations and challenges, we propose an elastic light scattering approach to spatiotemporally assess ECM microstructures in a relatively large area in a nondestructive manner. To demonstrate its feasibility, we analyze spectroscopic imaging data obtained from acellular collagen scaffolds and dermal equivalents as model ECM structures. For spatial characterization, acellular scaffolds are examined after a freeze/thaw process mimicking a cryopreservation procedure to quantify freezing-induced structural changes in the collagen matrix. We further analyze spatial and temporal changes in ECM structures during cell-driven compaction in dermal equivalents. The results show that spectral dependence of light elastically backscattered from engineered tissue is sensitively associated with alterations in ECM microstructures. In particular, a spectral decay rate over the wavelength can serve as an indicator for the pore size changes in ECM structures, which are at nanometer scale. A decrease in the spectral decay rate suggests enlarged pore sizes of ECM structures. The combination of this approach with a whole-field imaging platform further allows visualization of spatial heterogeneity of EMC microstructures in engineered tissues. This demonstrates the feasibility of the proposed method that nano- and micrometer scale alteration of the ECM structure can be detected and visualized at a whole-field level. Thus, we envision that this spectroscopic imaging approach could potentially serve as an effective characterization tool to nondestructively, accurately

  13. A Status Report on the Global Research in Microbial Metabolic Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Joe, Min Ho; Lim, Sang Yong; Kim, Dong Ho

    2008-09-15

    Biotechnology industry is now a global 'Mega-Trend' and metabolic engineering technology has important role is this area. Therefore, many countries has made efforts in this field to produce top value added bio-products efficiently using microorganisms. It has been applied to increase the production of chemicals that are already produced by the host organism, to produce desired chemical substances from less expensive feedstock, and to generate products that are new to the host organism. Recent experimental advances, the so-called '-omics' technologies, mainly functional genomics, proteomics and metabolomics, have enabled wholesale generation of new genomic, transcriptomic, proteomic, and metabolomic data. This report provides the insights of the integrated view of metabolism generated by metabolic engineering for biotechnological applications of microbial metabolic engineering.

  14. Modified chitosan hydrogels as drug delivery and tissue engineering systems: present status and applications

    Directory of Open Access Journals (Sweden)

    Tapan Kumar Giri

    2012-10-01

    Full Text Available Chitosan, a natural cationic polysaccharide, is prepared industrially by the hydrolysis of the aminoacetyl groups of chitin, a naturally available marine polymer. Chitosan is a non-toxic, biocompatible and biodegradable polymer and has attracted considerable interest in a wide range of biomedical and pharmaceutical applications including drug delivery, cosmetics, and tissue engineering. The primary hydroxyl and amine groups located on the backbone of chitosan are responsible for the reactivity of the polymer and also act as sites for chemical modification. However, chitosan has certain limitations for use in controlled drug delivery and tissue engineering. These limitations can be overcome by chemical modification. Thus, modified chitosan hydrogels have gained importance in current research on drug delivery and tissue engineering systems. This paper reviews the general properties of chitosan, various methods of modification, and applications of modified chitosan hydrogels.

  15. Life-cycle assessment of engineered nanomaterials: A literature review of assessment status

    DEFF Research Database (Denmark)

    Miseljic, Mirko; Olsen, Stig Irving

    2014-01-01

    The potential environmental impacts of engineered nanomaterials (ENMs), and their engineered nanoparticles (ENPs), have, in recent years, been a cause of concern. Life-cycle assessment (LCA) is a highly qualified tool to assess products and systems and has an increasing extent been applied to ENMs....... However, still only 29 case studies on LCA of ENMs have been published in journals and this article investigates these studies. Generally, data on production of ENMs as well as the coverage of the life cycle are limited. In particular, within use and disposal stages data are scarce due to many unknowns...

  16. Radiological, physical, and chemical characterization of transuranic wastes stored at the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Apel, M.L.; Becker, G.K.; Ragan, Z.K.; Frasure, J.; Raivo, B.D.; Gale, L.G.; Pace, D.P.

    1994-03-01

    This document provides radiological, physical and chemical characterization data for transuranic radioactive wastes and transuranic radioactive and hazardous (i.e., mixed) wastes stored at the Idaho National Engineering Laboratory and considered for treatment under the Private Sector Participation Initiative Program (PSPI). Waste characterization data are provided in the form of INEL Waste Profile Sheets. These documents provide, for each content code, information on waste identification, waste description, waste storage configuration, physical/chemical waste composition, radionuclide and associated alpha activity waste characterization data, and hazardous constituents present in the waste. Information is provided for 139 waste streams which represent an estimated total volume of 39,380{sup 3} corresponding to a total mass of approximately 19,000,000 kg. In addition, considerable information concerning alpha, beta, gamma, and neutron source term data specific to Rocky Flats Plant generated waste forms stored at the INEL are provided to assist in facility design specification.

  17. 77 FR 41350 - Monsanto Co.; Determination of Nonregulated Status of Soybean Genetically Engineered To Produce...

    Science.gov (United States)

    2012-07-13

    ... article under our regulations governing the introduction of certain genetically engineered organisms. Our....aphis.usda.gov/biotechnology/not_reg.html and are posted with the previous notice and the comments we..., Biotechnology Regulatory Services, APHIS, 4700 River Road Unit 147, Riverdale, MD 20737-1236; (301) 851-3954...

  18. 76 FR 78232 - Monsanto Co.; Determination of Nonregulated Status for Soybean Genetically Engineered To Have a...

    Science.gov (United States)

    2011-12-16

    ... the introduction of certain genetically engineered organisms. Our determination is based on our.../biotechnology/not_reg.html and are posted with the previous notice and the comments we received on the... INFORMATION CONTACT: Mr. Evan Chestnut, Policy Analyst, Biotechnology Regulatory Services, APHIS, 4700 River...

  19. Supplementation with engineered Lactococcus lactis improves the folate status in deficient rats

    NARCIS (Netherlands)

    LeBlanc, J.G.; Sybesma, W.F.H.; Starrenburg, M.; Sesma, F.; Vos, de W.M.; Giori, de G.S.; Hugenholtz, J.

    2010-01-01

    Objective: The aim of this study was to establish the bioavailability of different folates produced by engineered Lactococcus lactis strains using a rodent depletion-repletion bioassay. Methods: Rats were fed a folate-deficient diet, which produces a reversible subclinical folate deficiency,

  20. Avco Lycoming/NASA contract status. [on reduction of emissions from aircraft piston engines

    Science.gov (United States)

    Duke, L. C.

    1976-01-01

    The standards promulgated by the Environmental Protection Agency (EPA) for carbon monoxide (CO), unburned hydrocarbon (HC), and oxides-of-nitrogen (NOx) emissions were the basis in a study of ways to reduce emissions from aircraft piston engines. A variable valve timing system, ultrasonic fuel atomization, and ignition system changes were postulated.

  1. Metabolic engineering of Saccharomyces cerevisiae for production of carboxylic acids: current status and challenges.

    Science.gov (United States)

    Abbott, Derek A; Zelle, Rintze M; Pronk, Jack T; van Maris, Antonius J A

    2009-12-01

    To meet the demands of future generations for chemicals and energy and to reduce the environmental footprint of the chemical industry, alternatives for petrochemistry are required. Microbial conversion of renewable feedstocks has a huge potential for cleaner, sustainable industrial production of fuels and chemicals. Microbial production of organic acids is a promising approach for production of chemical building blocks that can replace their petrochemically derived equivalents. Although Saccharomyces cerevisiae does not naturally produce organic acids in large quantities, its robustness, pH tolerance, simple nutrient requirements and long history as an industrial workhorse make it an excellent candidate biocatalyst for such processes. Genetic engineering, along with evolution and selection, has been successfully used to divert carbon from ethanol, the natural endproduct of S. cerevisiae, to pyruvate. Further engineering, which included expression of heterologous enzymes and transporters, yielded strains capable of producing lactate and malate from pyruvate. Besides these metabolic engineering strategies, this review discusses the impact of transport and energetics as well as the tolerance towards these organic acids. In addition to recent progress in engineering S. cerevisiae for organic acid production, the key limitations and challenges are discussed in the context of sustainable industrial production of organic acids from renewable feedstocks.

  2. Characterization of Thermal Stability of Synthetic and Semi-Synthetic Engine Oils

    Directory of Open Access Journals (Sweden)

    Anand Kumar Tripathi

    2015-03-01

    Full Text Available Engine oils undergo oxidative degradation and wears out during service. Hence it is important to characterize ageing of engine oils at different simulated conditions to evaluate the performance of existing oils and also design new formulations. This work focuses on characterizing the thermo-oxidative degradation of synthetic and semi-synthetic engine oils aged at 120, 149 and 200 °C. Apparent activation energy of decomposition of aged oils evaluated using the isoconversional Kissinger-Akahira-Sunose technique was used as a thermal stability marker. The temporal variation of stability at different ageing temperatures was corroborated with kinematic viscosity, oxidation, sulfation and nitration indices, total base number, antiwear additive content and molecular structure of the organic species present in the oils. At the lowest temperature employed, synthetic oil underwent higher rate of oxidation, while semi-synthetic oil was stable for longer time periods. At higher temperatures, the initial rate of change of average apparent activation energy of synthetic oil correlated well with a similar variation in oxidation number. A mixture of long chain linear, branched, and cyclic hydrocarbons were observed when semi-synthetic oil was degraded at higher temperatures.

  3. Development and characterization of decellularized human nasoseptal cartilage matrix for use in tissue engineering.

    Science.gov (United States)

    Graham, M Elise; Gratzer, Paul F; Bezuhly, Michael; Hong, Paul

    2016-10-01

    Reconstruction of cartilage defects in the head and neck can require harvesting of autologous cartilage grafts, which can be associated with donor site morbidity. To overcome this limitation, tissue-engineering approaches may be used to generate cartilage grafts. The objective of this study was to decellularize and characterize human nasoseptal cartilage with the aim of generating a biological scaffold for cartilage tissue engineering. Laboratory study using nasoseptal cartilage. Remnant human nasoseptal cartilage specimens were collected and subjected to a novel decellularization treatment. The decellularization process involved several cycles of enzymatic detergent treatments. For characterization, decellularized and fresh (control) specimens underwent histological, biochemical, and mechanical analyses. Scanning electron microscopy and biocompatibility assay were also performed. The decellularization process had minimal effect on glycosaminoglycan content of the cartilage extracellular matrix. Deoxyribonucleic acid (DNA) analysis revealed the near-complete removal of genomic DNA from decellularized tissues. The effectiveness of the decellularization process was also confirmed on histological and scanning electron microscopic analyses. Mechanical testing results showed that the structural integrity of the decellularized tissue was maintained, and biocompatibility was confirmed. Overall, the current decellularization treatment resulted in significant reduction of genetic/cellular material with preservation of the underlying extracellular matrix structure. This decellularized material may serve as a potential scaffold for cartilage tissue engineering. N/A. Laryngoscope, 126:2226-2231, 2016. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  4. Detailed Characterization of Particulate Matter Emitted by Lean-Burn Gasoline Direct Injection Engine

    Energy Technology Data Exchange (ETDEWEB)

    Zelenyuk, Alla; Wilson, Jacqueline M.; Imre, Dan G.; Stewart, Mark L.; Muntean, George G.; Storey, John; Prikhodko, Vitaly; Lewis, Samuel T.; Eibl, Mary; Parks, James E.

    2017-08-01

    This study presents detailed characterization of the chemical and physical properties of PM emitted by a 2.0L BMW lean-burn turbocharged GDI engine operated under a number of combustion strategies that include lean homogeneous, lean stratified, stoichiometric, and fuel rich conditions. We characterized PM number concentrations, size distributions, and the size, mass, compositions, and effective density of fractal and compact individual exhaust particles. For the fractal particles, these measurements yielded fractal dimension, average diameter of primary spherules, and number of spherules, void fraction, and dynamic shape factors as function of particle size. Overall, the PM properties were shown to vary significantly with engine operation condition. Lean stratified operation yielded the most diesel-like size distribution and the largest PM number and mass concentrations, with nearly all particles being fractal agglomerates composed of elemental carbon with small amounts of ash and organics. In contrast, stoichiometric operation yielded a larger fraction of ash particles, especially at low speed and low load. Three distinct forms of ash particles were observed, with their fractions strongly dependent on engine operating conditions: sub-50 nm ash particles, abundant at low speed and low load, ash-containing fractal particles, and large compact ash particles that significantly contribute to PM mass loadings

  5. Characterizing Design Cognition of High School Students: Initial Analyses Comparing Those with and without Pre-Engineering Experiences

    Science.gov (United States)

    Wells, John; Lammi, Matthew; Gero, John; Grubbs, Michael E.; Paretti, Marie; Williams, Christopher

    2016-01-01

    Reported in this article are initial results from of a longitudinal study to characterize the design cognition and cognitive design styles of high school students with and without pre-engineering course experience over a 2-year period, and to compare them with undergraduate engineering students. The research followed a verbal protocol analysis…

  6. Characterization of biomass producer gas as fuel for stationary gas engines in combined heat and power production

    DEFF Research Database (Denmark)

    Ahrenfeldt, Jesper

    2008-01-01

    The aim of this project has been the characterization of biomass producer gas as a fuel for stationary gas engines in heat and power production. More than 3200 hours of gas engine operation, with producer gas as fuel, has been conducted at the biomass gasification combined heat and power (CHP...

  7. The design status of the liquid lithium target facility of IFMIF at the end of the engineering design activities

    Energy Technology Data Exchange (ETDEWEB)

    Nitti, F.S., E-mail: francesco.nitti@enea.it [IFMIF/EVEDA Project Team, Rokkasho Japan (Japan); Ibarra, A. [CIEMAT, Madrid (Spain); Ida, M. [IHI Corporation, Tokyo (Japan); Favuzza, P. [ENEA Research Center Firenze (Italy); Furukawa, T. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Groeschel, F. [KIT Research Center, Karlsruhe (Germany); Heidinger, R. [F4E Research Center, Garching (Germany); Kanemura, T. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Knaster, J. [IFMIF/EVEDA Project Team, Rokkasho Japan (Japan); Kondo, H. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Micchiche, G. [ENEA Research Center, Brasimone (Italy); Sugimoto, M. [JAEA Research Center, Rokkasho Japan (Japan); Wakai, E. [JAEA Research Center, Tokai-mura, Ibaraki (Japan)

    2015-11-15

    Highlights: • Results of validation and design activity for the Li loop facility of IFMIF. • Demonstration of Li target stability, with surface disturbance <1 mm. • Demonstration of start-up and shut down procedures of Li loop. • Complete design of the heat removal system and C and O purification system. • Conceptual design of N and H isotopes purification systems. - Abstract: The International Fusion Material Irradiation Facility (IFMIF) is an experimental facility conceived for qualifying and characterizing structural materials for nuclear fusion applications. The Engineering Validation and Engineering Design Activity (EVEDA) is a fundamental step towards the final design. It presented two mandates: the Engineering Validation Activities (EVA), still on-going, and the Engineering Design Activities (EDA) accomplished on schedule in June 2013. Five main facilities are identified in IFMIF, among which the Lithium Target Facility constituted a technological challenge overcome thanks to the success of the main validation challenges impacting the design. The design of the liquid Lithium Target Facility at the end of the EDA phase is here detailed.

  8. Characterization of the New Status of Nador Lagoon (Morocco after the Implementation of the Management Plan

    Directory of Open Access Journals (Sweden)

    Najih Mohamed

    2017-01-01

    Full Text Available The present study was carried out in 2011 with the aims of (1 evaluating the changes in sedimentary distribution that occurred in Nador lagoon seabed (Morocco after the implementation of the lagoon management plan in 2009; and (2 characterizing its new sedimentary status in 2011. Due to the lack of a baseline, we used the 1992 sedimentary status for comparison. The seabed surface sediment distribution showed a great change between 1992 and 2011. We found the same four sediment facies, which were present in 1992, namely: mud, sandy mud, muddy sand, and fine sand. However, in 2011, mud covered more than 54% of the lagoon seabed surface, mostly located in the middle part of the seabed, whereas in 1992, more than 80% of the lagoon seabed was covered by sandy mud. The sediments’ characteristics showed moderately to poorly sorted facies (S0, ranging between platykurtic and leptokurtic (SK and with various symmetry indices (SG. The organic matter content in sediment has strongly decreased, from values higher than 20% in most areas in 1992 to a mean value of 3.9% in 2011, ranging from 0.2% to 10.4%, thus confirming that the management actions implemented in 2009 were likely effective in reducing the organic pollution.

  9. JANNAF "Test and Evaluation Guidelines for Liquid Rocket Engines": Status and Application

    Science.gov (United States)

    Parkinson, Douglas; VanLerberghe, Wayne M.; Rahman, Shamim A.

    2017-01-01

    For many decades, the U.S. rocket propulsion industrial base has performed remarkably in developing complex liquid rocket engines that can propel critical payloads into service for the nation, as well as transport people and hardware for missions that open the frontiers of space exploration for humanity. This has been possible only at considerable expense given the lack of detailed guidance that captures the essence of successful practices and knowledge accumulated over five decades of liquid rocket engine development. In an effort to provide benchmarks and guidance for the next generation of rocket engineers, the Joint Army Navy NASA Air Force (JANNAF) Interagency Propulsion Committee published a liquid rocket engine (LRE) test and evaluation (T&E) guideline document in 2012 focusing on the development challenges and test verification considerations for liquid rocket engine systems. This document has been well received and applied by many current LRE developers as a benchmark and guidance tool, both for government-driven applications as well as for fully commercial ventures. The USAF Space and Missile Systems Center (SMC) has taken an additional near-term step and is directing activity to adapt and augment the content from the JANNAF LRE T&E guideline into a standard for potential application to future USAF requests for proposals for LRE development initiatives and launch vehicles for national security missions. A draft of this standard was already sent out for review and comment, and is intended to be formally approved and released towards the end of 2017. The acceptance and use of the LRE T&E guideline is possible through broad government and industry participation in the JANNAF liquid propulsion committee and associated panels. The sponsoring JANNAF community is expanding upon this initial baseline version and delving into further critical development aspects of liquid rocket propulsion testing at the integrated stage level as well as engine component level, in

  10. Challenges of river basin management: Current status of, and prospects for, the River Danube from a river engineering perspective.

    Science.gov (United States)

    Habersack, Helmut; Hein, Thomas; Stanica, Adrian; Liska, Igor; Mair, Raimund; Jäger, Elisabeth; Hauer, Christoph; Bradley, Chris

    2016-02-01

    In the Danube River Basin multiple pressures affect the river system as a consequence of river engineering works, altering both the river hydrodynamics and morphodynamics. The main objective of this paper is to identify the effects of hydropower development, flood protection and engineering works for navigation on the Danube and to examine specific impacts of these developments on sediment transport and river morphology. Whereas impoundments are characterised by deposition and an excess of sediment with remobilisation of fine sediments during severe floods, the remaining five free flowing sections of the Danube are experiencing river bed erosion of the order of several centimetres per year. Besides the effect of interruption of the sediment continuum, river bed degradation is caused by an increase in the sediment transport capacity following an increase in slope, a reduction of river bed width due to canalisation, prohibition of bank erosion by riprap or regressive erosion following base level lowering by flood protection measures and sediment dredging. As a consequence, the groundwater table is lowered, side-arms are disconnected, instream structures are lost and habitat quality deteriorates affecting the ecological status of valuable floodplains. The lack of sediments, together with cutting off meanders, leads also to erosion of the bed of main arms in the Danube Delta and coastal erosion. This paper details the causes and effects of river engineering measures and hydromorphological changes for the Danube. It highlights the importance of adopting a basin-wide holistic approach to river management and demonstrates that past management in the basin has been characterised by a lack of integration. To-date insufficient attention has been paid to the wide-ranging impacts of river engineering works throughout the basin: from the basin headwaters to the Danube Delta, on the Black Sea coast. This highlights the importance of new initiatives that seek to advance knowledge

  11. Current status of genetic engineering in cotton (Gossypium hirsutum L): an assessment.

    Science.gov (United States)

    Chakravarthy, Vajhala S K; Reddy, Tummala Papi; Reddy, Vudem Dashavantha; Rao, Khareedu Venkateswara

    2014-06-01

    Cotton is considered as the foremost commercially important fiber crop and is deemed as the backbone of the textile industry. The productivity of cotton crop, worldwide, is severely hampered by the occurrence of pests, weeds, pathogens apart from various environmental factors. Several beneficial agronomic traits, viz., early maturity, improved fiber quality, heat tolerance, etc. have been successfully incorporated into cotton varieties employing conventional hybridization and mutation breeding. Crop losses, due to biotic factors, are substantial and may be reduced through certain crop protection strategies. In recent years, pioneering success has been achieved through the adoption of modern biotechnological approaches. Genetically engineered cotton varieties, expressing Bacillus thuringiensis cry genes, proved to be highly successful in controlling the bollworm complex. Various other candidate genes responsible for resistance to insect pests and pathogens, tolerance to major abiotic stress factors such as temperature, drought and salinity, have been introduced into cotton via genetic engineering methods to enhance the agronomic performance of cotton cultivars. Furthermore, genes for improving the seed oil quality and fiber characteristics have been identified and introduced into cotton cultivars. This review provides a brief overview of the various advancements made in cotton through genetic engineering approaches.

  12. Eleventh symposium on energy engineering sciences: Proceedings. Solid mechanics and processing: Analysis, measurement and characterization

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    The Eleventh Symposium on Energy Engineering Sciences was held on May 3--5, 1993, at the Argonne National Laboratory, Argonne, Illinois. These proceedings include the program, list of participants, and the papers that were presented during the eight technical sessions held at this meeting. This symposium was organized into eight technical sessions: Surfaces and interfaces; thermophysical properties and processes; inelastic behavior; nondestructive characterization; multiphase flow and thermal processes; optical and other measurement systems; stochastic processes; and large systems and control. Individual projects were processed separately for the databases.

  13. Characterization of hybrid lighting systems of the Electrical Engineering Building in the Industrial University of Santander

    Science.gov (United States)

    Galvis, D.; Exposito, C.; Osma, G.; Amado, L.; Ordóñez, G.

    2016-07-01

    This paper presents an analysis of hybrid lighting systems of Electrical Engineering Building in the Industrial University of Santander, which is a pilot of green building for warm- tropical conditions. Analysis of lighting performance of inner spaces is based on lighting curves obtained from characterization of daylighting systems of these spaces. A computation tool was made in Excel-Visual Basic to simulate the behaviour of artificial lighting system considering artificial control system, user behaviour and solar condition. Also, this tool allows to estimate the electrical energy consumption of the lighting system for a day, a month and a year.

  14. Assembly and characterization of megaTALs for hyperspecific genome engineering applications.

    Science.gov (United States)

    Boissel, Sandrine; Scharenberg, Andrew M

    2015-01-01

    Rare-cleaving nucleases have emerged as valuable tools for creating targeted genomic modification for both therapeutic and research applications. MegaTALs are novel monomeric nucleases composed of a site-specific meganuclease cleavage head with additional affinity and specificity provided by a TAL effector DNA binding domain. This fusion product facilitates the transformation of meganucleases into hyperspecific and highly active genome engineering tools that are amenable to multiplexing and compatible with multiple cellular delivery methods. In this chapter, we describe the process of assembling a megaTAL from a meganuclease, as well as a method for characterization of nuclease cleavage activity in vivo using a fluorescence reporter assay.

  15. Characterization of the human plasma phosphoproteome using linear ion trap mass spectrometry and multiple search engines.

    Science.gov (United States)

    Carrascal, Montserrat; Gay, Marina; Ovelleiro, David; Casas, Vanessa; Gelpí, Emilio; Abian, Joaquin

    2010-02-05

    Major plasma protein families play different roles in blood physiology and hemostasis and in immunodefense. Other proteins in plasma can be involved in signaling as chemical messengers or constitute biological markers of the status of distant tissues. In this respect, the plasma phosphoproteome holds potentially relevant information on the mechanisms modulating these processes through the regulation of protein activity. In this work we describe for the first time a collection of phosphopeptides identified in human plasma using immunoaffinity separation of the seven major serum protein families from other plasma proteins, SCX fractionation, and TiO(2) purification prior to LC-MS/MS analysis. One-hundred and twenty-seven phosphosites in 138 phosphopeptides mapping 70 phosphoproteins were identified with FDR < 1%. A high-confidence collection of phosphosites was obtained using a combined search with the OMSSA, SEQUEST, and Phenyx search engines.

  16. A Model-Free Diagnosis Approach for Intake Leakage Detection and Characterization in Diesel Engines

    Directory of Open Access Journals (Sweden)

    Ghaleb Hoblos

    2015-07-01

    Full Text Available Feature selection is an essential step for data classification used in fault detection and diagnosis processes. In this work, a new approach is proposed, which combines a feature selection algorithm and a neural network tool for leak detection and characterization tasks in diesel engine air paths. The Chi square classifier is used as the feature selection algorithm and the neural network based on Levenberg-Marquardt is used in system behavior modeling. The obtained neural network is used for leak detection and characterization. The model is learned and validated using data generated by xMOD. This tool is used again for testing. The effectiveness of the proposed approach is illustrated in simulation when the system operates on a low speed/load and the considered leak affecting the air path is very small.

  17. PICASSO VISION instrument design, engineering model test results, and flight model development status

    Science.gov (United States)

    Näsilä, Antti; Holmlund, Christer; Mannila, Rami; Näkki, Ismo; Ojanen, Harri J.; Akujärvi, Altti; Saari, Heikki; Fussen, Didier; Pieroux, Didier; Demoulin, Philippe

    2016-10-01

    PICASSO - A PICo-satellite for Atmospheric and Space Science Observations is an ESA project led by the Belgian Institute for Space Aeronomy, in collaboration with VTT Technical Research Centre of Finland Ltd, Clyde Space Ltd. (UK) and Centre Spatial de Liège (BE). The test campaign for the engineering model of the PICASSO VISION instrument, a miniaturized nanosatellite spectral imager, has been successfully completed. The test results look very promising. The proto-flight model of VISION has also been successfully integrated and it is waiting for the final integration to the satellite platform.

  18. Martian Surface Boundary Layer Characterization: Enabling Environmental Data for Science, Engineering and Human Exploration

    Science.gov (United States)

    England, C.

    2000-01-01

    For human or large robotic exploration of Mars, engineering devices such as power sources will be utilized that interact closely with the Martian environment. Heat sources for power production, for example, will use the low ambient temperature for efficient heat rejection. The Martian ambient, however, is highly variable, and will have a first order influence on the efficiency and operation of all large-scale equipment. Diurnal changes in temperature, for example, can vary the theoretical efficiency of power production by 15% and affect the choice of equipment, working fluids, and operating parameters. As part of the Mars Exploration program, missions must acquire the environmental data needed for design, operation and maintenance of engineering equipment including the transportation devices. The information should focus on the variability of the environment, and on the differences among locations including latitudes, altitudes, and seasons. This paper outlines some of the WHY's, WHAT's and WHERE's of the needed data, as well as some examples of how this data will be used. Environmental data for engineering design should be considered a priority in Mars Exploration planning. The Mars Thermal Environment Radiator Characterization (MTERC), and Dust Accumulation and Removal Technology (DART) experiments planned for early Mars landers are examples of information needed for even small robotic missions. Large missions will require proportionately more accurate data that encompass larger samples of the Martian surface conditions. In achieving this goal, the Mars Exploration program will also acquire primary data needed for understanding Martian weather, surface evolution, and ground-atmosphere interrelationships.

  19. Characterization of pediatric microtia cartilage: a reservoir of chondrocytes for auricular reconstruction using tissue engineering strategies.

    Science.gov (United States)

    Melgarejo-Ramírez, Y; Sánchez-Sánchez, R; García-López, J; Brena-Molina, A M; Gutiérrez-Gómez, C; Ibarra, C; Velasquillo, C

    2016-09-01

    The external ear is composed of elastic cartilage. Microtia is a congenital malformation of the external ear that involves a small reduction in size or a complete absence. The aim of tissue engineering is to regenerate tissues and organs clinically implantable based on the utilization of cells and biomaterials. Remnants from microtia represent a source of cells for auricular reconstruction using tissue engineering. To examine the macromolecular architecture of microtia cartilage and behavior of chondrocytes, in order to enrich the knowledge of this type of cartilage as a cell reservoir. Auricular cartilage remnants were obtained from pediatric patients with microtia undergoing reconstructive procedures. Extracellular matrix composition was characterized using immunofluorescence and histological staining methods. Chondrocytes were isolated and expanded in vitro using a mechanical-enzymatic protocol. Chondrocyte phenotype was analyzed using qualitative PCR. Microtia cartilage preserves structural organization similar to healthy elastic cartilage. Extracellular matrix is composed of typical cartilage proteins such as type II collagen, elastin and proteoglycans. Chondrocytes displayed morphological features similar to chondrocytes derived from healthy cartilage, expressing SOX9, COL2 and ELN, thus preserving chondral phenotype. Cell viability was 94.6 % during in vitro expansion. Elastic cartilage from microtia has similar characteristics, both architectural and biochemical to healthy cartilage. We confirmed the suitability of microtia remnant as a reservoir of chondrocytes with potential to be expanded in vitro, maintaining phenotypical features and viability. Microtia remnants are an accessible source of autologous cells for auricular reconstruction using tissue engineering strategies.

  20. Optical characterization of nano-sized organic carbon particles emitted from a small gasoline engine

    Institute of Scientific and Technical Information of China (English)

    Bireswar Paul; Amitava Datta; Aparna Datta; Abhijit Saha

    2013-01-01

    The nano-sized organic carbon (NOC) particles emitted from a small gasoline engine were characterized using various ex situ optical techniques to assess their hazardous impact.The exhaust gas was sampled iso-kinetically by a quartz probe and passed through de-ionized water to gather the hydrophilic carbonaceous particulates as hydrosol.The hydrodynamic diameter of the particles ranged between 1.7 and 3.6 nm at no load,with a mean diameter of 2.4 nm.The particle size in the engine exhaust was found to increase at higher loads,which is attributed to coagulation of the particles.The chemical structure of the particles was analyzed using UV-vis and infra-red spectroscopy.Both the band gap energy and oscillator strength data evaluated from the UV-vis absorbance showed that the NOC particles contained polyaromatic hydrocarbon structures with three to five aromatic rings.Infra-red spectroscopy analysis further confirmed the presence of aliphatic and carbonyl functionalities in the aromatic structures of the particles.The fine size of the particles,their high number concentration for the type of the engine under study and their structural features,make the particles extremely hazardous for environment and health.

  1. Martian Surface Boundary Layer Characterization: Enabling Environmental Data for Science, Engineering and Human Exploration

    Science.gov (United States)

    England, C.

    2000-01-01

    For human or large robotic exploration of Mars, engineering devices such as power sources will be utilized that interact closely with the Martian environment. Heat sources for power production, for example, will use the low ambient temperature for efficient heat rejection. The Martian ambient, however, is highly variable, and will have a first order influence on the efficiency and operation of all large-scale equipment. Diurnal changes in temperature, for example, can vary the theoretical efficiency of power production by 15% and affect the choice of equipment, working fluids, and operating parameters. As part of the Mars Exploration program, missions must acquire the environmental data needed for design, operation and maintenance of engineering equipment including the transportation devices. The information should focus on the variability of the environment, and on the differences among locations including latitudes, altitudes, and seasons. This paper outlines some of the WHY's, WHAT's and WHERE's of the needed data, as well as some examples of how this data will be used. Environmental data for engineering design should be considered a priority in Mars Exploration planning. The Mars Thermal Environment Radiator Characterization (MTERC), and Dust Accumulation and Removal Technology (DART) experiments planned for early Mars landers are examples of information needed for even small robotic missions. Large missions will require proportionately more accurate data that encompass larger samples of the Martian surface conditions. In achieving this goal, the Mars Exploration program will also acquire primary data needed for understanding Martian weather, surface evolution, and ground-atmosphere interrelationships.

  2. Genetically engineered virus-resistant plants in developing countries: current status and future prospects.

    Science.gov (United States)

    Reddy, D V R; Sudarshana, M R; Fuchs, M; Rao, N C; Thottappilly, G

    2009-01-01

    Plant viruses cause severe crop losses worldwide. Conventional control strategies, such as cultural methods and biocide applications against arthropod, nematode, and plasmodiophorid vectors, have limited success at mitigating the impact of plant viruses. Planting resistant cultivars is the most effective and economical way to control plant virus diseases. Natural sources of resistance have been exploited extensively to develop virus-resistant plants by conventional breeding. Non-conventional methods have also been used successfully to confer virus resistance by transferring primarily virus-derived genes, including viral coat protein, replicase, movement protein, defective interfering RNA, non-coding RNA sequences, and protease, into susceptible plants. Non-viral genes (R genes, microRNAs, ribosome-inactivating proteins, protease inhibitors, dsRNAse, RNA modifying enzymes, and scFvs) have also been used successfully to engineer resistance to viruses in plants. Very few genetically engineered (GE) virus resistant (VR) crops have been released for cultivation and none is available yet in developing countries. However, a number of economically important GEVR crops, transformed with viral genes are of great interest in developing countries. The major issues confronting the production and deregulation of GEVR crops in developing countries are primarily socio-economic and related to intellectual property rights, biosafety regulatory frameworks, expenditure to generate GE crops and opposition by non-governmental activists. Suggestions for satisfactory resolution of these factors, presumably leading to field tests and deregulation of GEVR crops in developing countries, are given.

  3. DNA assembler: a synthetic biology tool for characterizing and engineering natural product gene clusters.

    Science.gov (United States)

    Shao, Zengyi; Zhao, Huimin

    2012-01-01

    The majority of existing antibacterial and anticancer drugs are natural products or their derivatives. However, the characterization and engineering of these compounds are often hampered by limited ability to manipulate the corresponding biosynthetic pathways. Recently, we developed a genomics-driven, synthetic biology-based method, DNA assembler, for discovery, characterization, and engineering of natural product biosynthetic pathways (Shao, Luo, & Zhao, 2011). By taking advantage of the highly efficient yeast in vivo homologous recombination mechanism, this method synthesizes the entire expression vector containing the target biosynthetic pathway and the genetic elements needed for DNA maintenance and replication in individual hosts in a single-step manner. In this chapter, we describe the general guidelines for construct design. By using two distinct biosynthetic pathways, we demonstrate that DNA assembler can perform multiple tasks, including heterologous expression, introduction of single or multiple point mutations, scar-less gene deletion, generation of product derivatives, and creation of artificial gene clusters. As such, this method offers unprecedented flexibility and versatility in pathway manipulations.

  4. High resolution characterization of engineered nanomaterial dispersions in complex media using tunable resistive pulse sensing technology.

    Science.gov (United States)

    Pal, Anoop K; Aalaei, Iraj; Gadde, Suresh; Gaines, Peter; Schmidt, Daniel; Demokritou, Philip; Bello, Dhimiter

    2014-09-23

    In vitro toxicity assessment of engineered nanomaterials (ENM), the most common testing platform for ENM, requires prior ENM dispersion, stabilization, and characterization in cell culture media. Dispersion inefficiencies and active aggregation of particles often result in polydisperse and multimodal particle size distributions. Accurate characterization of important properties of such polydisperse distributions (size distribution, effective density, charge, mobility, aggregation kinetics, etc.) is critical for understanding differences in the effective dose delivered to cells as a function of time and dispersion conditions, as well as for nano-bio interactions. Here we have investigated the utility of tunable nanopore resistive pulse sensing (TRPS) technology for characterization of four industry relevant ENMs (oxidized single-walled carbon nanohorns, carbon black, cerium oxide and nickel nanoparticles) in cell culture media containing serum. Harvard dispersion and dosimetry platform was used for preparing ENM dispersions and estimating delivered dose to cells based on dispersion characterization input from dynamic light scattering (DLS) and TRPS. The slopes of cell death vs administered and delivered ENM dose were then derived and compared. We investigated the impact of serum protein content, ENM concentration, and cell medium on the size distributions. The TRPS technology offers higher resolution and sensitivity compared to DLS and unique insights into ENM size distribution and concentration, as well as particle behavior and morphology in complex media. The in vitro dose-response slopes changed significantly for certain nanomaterials when delivered dose to cells was taken into consideration, highlighting the importance of accurate dispersion and dosimetry in in vitro nanotoxicology.

  5. Characterization of Fibrin and Collagen Gels for Engineering Wound Healing Models

    Directory of Open Access Journals (Sweden)

    Oihana Moreno-Arotzena

    2015-04-01

    Full Text Available Hydrogels are used for 3D in vitro assays and tissue engineering and regeneration purposes. For a thorough interpretation of this technology, an integral biomechanical characterization of the materials is required. In this work, we characterize the mechanical and functional behavior of two specific hydrogels that play critical roles in wound healing, collagen and fibrin. A coherent and complementary characterization was performed using a generalized and standard composition of each hydrogel and a combination of techniques. Microstructural analysis was performed by scanning electron microscopy and confocal reflection imaging. Permeability was measured using a microfluidic-based experimental set-up, and mechanical responses were analyzed by rheology. We measured a pore size of 2.84 and 1.69 μm for collagen and fibrin, respectively. Correspondingly, the permeability of the gels was 1.00·10−12 and 5.73·10−13 m2. The shear modulus in the linear viscoelastic regime was 15 Pa for collagen and 300 Pa for fibrin. The gels exhibited strain-hardening behavior at ca. 10% and 50% strain for fibrin and collagen, respectively. This consistent biomechanical characterization provides a detailed and robust starting point for different 3D in vitro bioapplications, such as collagen and/or fibrin gels. These features may have major implications for 3D cellular behavior by inducing divergent microenvironmental cues.

  6. Assessing Nebraska playa wetland inundation status during 1985-2015 using Landsat data and Google Earth Engine.

    Science.gov (United States)

    Tang, Zhenghong; Li, Yao; Gu, Yue; Jiang, Weiguo; Xue, Yuan; Hu, Qiao; LaGrange, Ted; Bishop, Andy; Drahota, Jeff; Li, Ruopu

    2016-12-01

    Playa wetlands in Nebraska provide globally important habitats for migratory waterfowl. Inundation condition is an important indicator of playa wetland functionality. However, there is a lack of long-term continuous monitoring records for playa wetlands. The objective of this study was to determine a suitable index for Landsat images to map the playa inundation status in March and April during 1985-2015. Four types of spectral indices-negative normalized vegetation index, Normalized Difference Water Index (NDWI), modified NDWI, and Tasseled Cap Wetness-Greenness Difference (TCWGD)-were evaluated to detect playa inundation conditions from Landsat images. The results indicate that the TCWGD is the most suitable index for distinguishing playa inundation status. By using Landsat images and Google Earth Engine, we mapped the spring inundation condition of Nebraska playas during 1985-2015. The results show that the total inundated areas were 176.79 km(2) in spring migratory season, representing 18.92% of the total area of playa wetlands. There were 9898 wetlands inundated at least once in either March or April during the past 30 years, representing 29.41% of a total of 33,659 historical wetlands. After comparing the historical hydric soil footprints and the inundated areas, the results indicate that the hydrological conditions of the majority of playas in Nebraska have changed. The inundated wetlands are candidates for protection and/or partial restoration, and the un-inundated wetlands need more attention for wetland restoration. Wetlands in areas enrolled in conservation easements had a significantly high level of playa inundation status than non-conserved wetlands during spring migratory seasons in the past decades.These conservation easements only count for 4.29% of the total footprint areas, but they have contributed 20.82% of the inundation areas in Nebraska during the past 30 years.

  7. High Frequency Acoustic Response Characterization and Analysis of the Deep Throttling Common Extensible Cryogenic Engine

    Science.gov (United States)

    Casiano, M. J.

    2011-01-01

    The Common Extensive Cryogenic Engine program demonstrated the operation of a deep throttling engine design. The program, spanning five years from August 2005 to July 2010, funded testing through four separate engine demonstration test series. Along with successful completion of multiple objectives, a discrete response of approximately 4000 Hz was discovered and explored throughout the program. The typical low-amplitude acoustic response was evident in the chamber measurement through almost every operating condition; however, at certain off-nominal operating conditions, the response became discrete with higher amplitude. This paper summarizes the data reduction, characterization, and analysis of the 4,000 Hz response for the entire program duration, using the large amount of data collected. Upon first encountering the response, new objectives and instrumentation were incorporated in future test series to specifically collect 4,000 Hz data. The 4,000 Hz response was identified as being related to the first tangential acoustic mode by means of frequency estimation and spatial decomposition. The latter approach showed that the effective node line of the mode was aligned with the manifold propellant inlets with standing waves and quasi-standing waves present at various times. Contour maps that contain instantaneous frequency and amplitude trackings of the response were generated as a significant improvement to historical manual approaches of data reduction presentation. Signal analysis and dynamic data reduction also uncovered several other features of the response including a stable limit cycle, the progressive engagement of subsequent harmonics, the U-shaped time history, an intermittent response near the test-based neutral stability region, other acoustic modes, and indications of modulation with a separate subsynchronous response. Although no engine damage related to the acoustic mode was noted, the peak-to-peak fluctuating pressure amplitude achieved 12.1% of the

  8. Characterization of TEMPO-oxidized bacterial cellulose scaffolds for tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Honglin [School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Xiong, Guangyao [School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang, Jiangxi 330013 (China); Hu, Da [School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Ren, Kaijing [Department of Joint Surgery, Tianjin Hospital, Tianjin 300211 (China); Yao, Fanglian; Zhu, Yong [School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Gao, Chuan [School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Wan, Yizao, E-mail: yzwantju@126.com [School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

    2013-12-16

    Introduction of active groups on the surface of bacterial cellulose (BC) nanofibers is one of the promising routes of tailoring the performance of BC scaffolds for tissue engineering. This paper reported the introduction of aldehyde groups to BC nanofibers by 2,2,6,6-tetramethylpyperidine-1-oxy radical (TEMPO)-mediated oxidation and evaluation of the potential of the TEMPO-oxidized BC as tissue engineering scaffolds. Periodate oxidation was also conducted for comparison. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses were carried out to determine the existence of aldehyde groups on BC nanofibers and the crystallinity. In addition, properties relevant to scaffold applications such as morphology, fiber diameter, mechanical properties, and in vitro degradation were characterized. The results indicated that periodate oxidation could introduce free aldehyde to BC nanofibers and the free aldehyde groups on the TEMPO-oxidized BC tended to transfer to acetal groups. It was also found that the advantageous 3D structure of BC scaffolds remained unchanged and that no significant changes in morphology, fiber diameter, tensile structure and in vitro degradation were found after TEMPO-mediated oxidation while significant differences were observed upon periodate oxidation. The present study revealed that TEMPO-oxidation could impart BC scaffolds with new functions while did not degrade their intrinsic advantages. - Highlights: • TEMPO-mediated oxidation on BC scaffold for tissue engineering use was conducted. • TEMPO-mediated oxidation did not degrade the intrinsic advantages of BC scaffold. • TEMPO-mediated oxidation could impart BC scaffold with new functional groups. • Feasibility of TEMPO-oxidized BC as tissue engineering scaffold was confirmed.

  9. Present Status and Future Prospects of Geothermal Development in Italy with an Appendix on Reservoir Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Cataldi, R.; Calamai, A.; Neri, G.; Manetti, G.

    1983-12-15

    This paper consists of two parts and an appendix. In the first part a review is made of the geothermal activity in Italy from 1975 to 1982, including electrical and non-electrical applications. Remarks then follow on the trends that occurred and the operational criteria that were applied in the same period, which can be considered a transitional period of geothermal development in Italy. Information on recent trends and development objectives up to 1990 are given in the second part of the paper, together with a summary on program activities in the various geothermal areas of Italy. The appendix specifically reviews the main reseroir engineering activities carried out in the past years and the problems likely to be faced in the coming years in developing Itallian fields.

  10. Status on Technology Development of Optic Fiber-Coupled Laser Ignition System for Rocket Engine Applications

    Science.gov (United States)

    Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew; Bossard, John

    2003-01-01

    To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concept: not only offer system simplicity, but also enhance the combustion performance. Test results have shown that chamber performance is markedly high even at a low chamber length-to-diameter ratio. This incentive can be translated to a convenience in the thrust chamber packaging.

  11. The status of soil mapping for the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Olson, G.L.; Lee, R.D. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Jeppesen, D.J. [Department of Interior, Idaho Falls, ID (United States)

    1995-01-01

    This report discusses the production of a revised version of the general soil map of the 2304-km{sup 2} (890-mi{sup 2}) Idaho National Engineering Laboratory (INEL) site in southeastern Idaho and the production of a geographic information system (GIS) soil map and supporting database. The revised general soil map replaces an INEL soil map produced in 1978 and incorporates the most current information on INEL soils. The general soil map delineates large soil associations based on National Resources Conservation Services [formerly the Soil Conservation Service (SCS)] principles of soil mapping. The GIS map incorporates detailed information that could not be presented on the general soil map and is linked to a database that contains the soil map unit descriptions, surficial geology codes, and other pertinent information.

  12. Status report. Characterization of Weld Residual Stresses on a Full-Diameter SNF Interim Storage Canister Mockup.

    Energy Technology Data Exchange (ETDEWEB)

    Enos, David [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Bryan, Charles R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    This report documents the mockup specifications and manufacturing processes; the initial cutting of the mockup into three cylindrical pieces for testing and the measured strain changes that occurred during the cutting process; and the planned weld residual stress characterization activities and the status of those activities.

  13. Report on the present status of scientific and engineering accelerators in Japan (I)

    CERN Document Server

    2003-01-01

    For the purpose to know the present status of possible joint researches in use of accelerators in Japan, the Specialist Committee of Quantum Beam conducted a questionnaire to 69 organizations, of which 54 answered. The organizations have 97 accelerator facilities, which had 108 machines for research and educational purpose, and 7 for medical use. Of 97 facilities, 86 are found open for joint and cooperative researches. Based on the questionnaire results, following discussions are made: Definition and classification of quantum beam; Positioning of accelerators for research purpose among all machines in Japan (Increase of accelerator usage, economical scale and social contribution); Usage form of accelerators for research purpose (sort of accelerators, sort of secondary ions like neutron, synchrotron radiation, positron, radioisotope beam, muon and neutrino, high current accelerator for fusion, measurement and analyses, new elements, PET and gamma-ray); and The questionnaire results of the accelerators for rese...

  14. Discussion on engineering cost status and stage management%谈工程造价的现状与阶段管理

    Institute of Scientific and Technical Information of China (English)

    张星魁

    2012-01-01

    This paper briefly analyzes the development status of domestic engineering cost,points out problems existing in current domestic engineering cost,and describes the management points of engineering cost at various phases,so as to promote the development of domestic engineering cost and to improve the stage management level of engineering cost.%对我国工程造价的发展现状进行了简要分析,指出了目前国内工程造价存在的问题,阐述了工程造价各阶段的管理要点,以期促进我国工程造价的发展,提高工程造价的阶段管理水平。

  15. Status of the laboratory infrastructure for detector calibration and characterization at the European XFEL

    Science.gov (United States)

    Raab, N.; Ballak, K.-E.; Dietze, T.; Ekmedzič, M.; Hauf, S.; Januschek, F.; Kaukher, A.; Kuster, M.; Lang, P. M.; Münnich, A.; Schmitt, R.; Sztuk-Dambietz, J.; Turcato, M.

    2016-12-01

    The European X-ray Free Electron Laser (XFEL.EU) will provide unprecedented peak brilliance and ultra-short and spatially coherent X-ray pulses in an energy range of 0.25 to 25 keV . The pulse timing structure is unique with a burst of 2700 pulses of 100 fs length at a temporal distance of 220 ns followed by a 99.4 ms gap. To make optimal use of this timing structure and energy range a great variety of detectors are being developed for use at XFEL.EU, including 2D X-ray imaging cameras that are able to detect images at a rate of 4.5 MHz, provide dynamic ranges up to 105 photons per pulse per pixel under different operating conditions and covering a large range of angular resolution \\cite{requirements,Markus}. In order to characterize, commission and calibrate this variety of detectors and for testing of detector prototypes the XFEL.EU detector group is building up an X-ray test laboratory that allows testing of detectors with X-ray photons under conditions that are as similar to the future beam line conditions at the XFEL.EU as is possible with laboratory sources [1]. A total of four test environments provide the infrastructure for detector tests and calibration: two portable setups that utilize low power X-ray sources and radioactive isotopes, a test environment where a commercial high power X-ray generator is in use, and a pulsed X-ray/electron source which will provide pulses as short as 25 ns in XFEL.EU burst mode combined with target anodes of different materials. The status of the test environments, three of which are already in use while one is in commissioning phase, will be presented as well as first results from performance tests and characterization of the sources.

  16. Status of volcanism studies for the Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Crowe, B.; Perry, F.; Murrell, M.; Poths, J.; Valentine, G.A. [Los Alamos National Lab., NM (United States); Wells, S. [Univ. of California, Riverside, CA (United States); Bowker, L.; Finnegan, K. [Univ. of Nevada, Las Vegas, NV (United States); Geissman, J.; McFadden, L.

    1995-02-01

    Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. Geophysical data are described for the YMR and are used as an aid to understand the distribution of basaltic volcanic centers. Chapter 4 discusses the petrologic and geochemical features of basaltic volcanism in the YMR, the southern Great Basin and the Basin and Range province. The long time of activity and characteristic small volume of the Postcaldera basalt of the YMR result in one of the lowest eruptive rates in a volcanic field in the southwest United States. Chapter 5 summarizes current concepts of the segregation, ascent, and eruption of basalt magma. Chapter 6 summarizes the history of volcanism studies (1979 through early 1994), including work for the Yucca Mountain Site Characterization Project and overview studies by the state of Nevada and the Nuclear Regulatory Commission. Chapter 7 summarizes probabilistic volcanic hazard assessment using a three-part conditional probability model. Chapter 8 describes remaining volcanism work judged to be needed to complete characterization studies for the YMR. Chapter 9 summarizes the conclusions of this volcanism status report.

  17. Use of Adult Stem Cells for Cartilage Tissue Engineering: Current Status and Future Developments

    Directory of Open Access Journals (Sweden)

    Catherine Baugé

    2015-01-01

    Full Text Available Due to their low self-repair ability, cartilage defects that result from joint injury, aging, or osteoarthritis, are the most often irreversible and are a major cause of joint pain and chronic disability. So, in recent years, researchers and surgeons have been working hard to elaborate cartilage repair interventions for patients who suffer from cartilage damage. However, current methods do not perfectly restore hyaline cartilage and may lead to the apparition of fibro- or hypertrophic cartilage. In the next years, the development of new strategies using adult stem cells, in scaffolds, with supplementation of culture medium and/or culture in low oxygen tension should improve the quality of neoformed cartilage. Through these solutions, some of the latest technologies start to bring very promising results in repairing cartilage from traumatic injury or chondropathies. This review discusses the current knowledge about the use of adult stem cells in the context of cartilage tissue engineering and presents clinical trials in progress, as well as in the future, especially in the field of bioprinting stem cells.

  18. NASA Engineering Safety Center NASA Aerospace Flight Battery Systems Working Group 2007 Proactive Task Status

    Science.gov (United States)

    Manzo, Michelle A.

    2007-01-01

    In 2007, the NASA Engineering Safety Center (NESC) chartered the NASA Aerospace Flight Battery Systems Working Group to bring forth and address critical battery-related performance/manufacturing issues for NASA and the aerospace community. A suite of tasks identifying and addressing issues related to Ni-H2 and Li-ion battery chemistries was submitted and selected for implementation. The current NESC funded are: (1) Wet Life of Ni-H2 Batteries (2) Binding Procurement (3) NASA Lithium-Ion Battery Guidelines (3a) Li-Ion Performance Assessment (3b) Li-Ion Guidelines Document (3b-i) Assessment of Applicability of Pouch Cells for Aerospace Missions (3b-ii) High Voltage Risk Assessment (3b-iii) Safe Charge Rates for Li-Ion Cells (4) Availability of Source Material for Li-Ion Cells (5) NASA Aerospace Battery Workshop This presentation provides a brief overview of the tasks in the 2007 plan and serves as an introduction to more detailed discussions on each of the specific tasks.

  19. Engineering Geological and Petrographic Characterization of Migmatites Belonging to the Calabria-Peloritani Orogen (Southern Italy)

    Science.gov (United States)

    Pappalardo, G.; Punturo, R.; Mineo, S.; Ortolano, G.; Castelli, F.

    2016-04-01

    The laboratory characterization of migmatite rocks, affected by tunneling works in southern Calabria (Italy), has been carried out with the purpose of investigating the relationship between some potentially interdependent petrographic and petrophysical features with the mechanical behavior of the excavated rocks. Mineralogical and petrographic investigation allowed estimating the modal composition of the rock and the grain size of the constituting minerals, as well as examining the intergranular contacts and associated microfractures. The velocity of seismic waves within the specimens has been measured and calculated, along with the elastic properties of the rock. Specimens were also characterized from the physical-mechanical point of view and their mode of failure was considered. Results show that the mechanical behavior of migmatites varies within the sample population, although the specimens belong to the same sampling area. It is controlled by both porosity and modal composition of the rock. Thus, primary minerals were grouped with respect to their elastic properties; their abundance/deficiency within the specimen controls its mechanical strength. This is also reflected in the modes of failure associated to different strength values. This is a new consideration in the laboratory characterization of this rock type, largely cropping out in several contexts worldwide. Results should be taken into account before starting engineering works, in order to avoid errors resulting from considering this rock as a homogeneous material from the mechanical and petrographic points of view.

  20. Engineered materials characterization report, volume 3 - corrosion data and modeling update for viability assessments

    Energy Technology Data Exchange (ETDEWEB)

    McCright, R D

    1998-06-30

    This Engineered Materials Characterization Report (EMCR), Volume 3, discusses in considerable detail the work of the past 18 months on testing the candidate materials proposed for the waste-package (WP) container and on modeling the performance of those materials in the Yucca Mountain (YM) repository setting This report was prepared as an update of information and serves as one of the supporting documents to the Viability Assessment (VA) of the Yucca Mountain Project. Previous versions of the EMCR have provided a history and background of container-materials selection and evaluation (Volume I), a compilation of physical and mechanical properties for the WP design effort (Volume 2), and corrosion-test data and performance-modeling activities (Volume 3). Because the information in Volumes 1 and 2 is still largely current, those volumes are not being revised. As new information becomes available in the testing and modeling efforts, Volume 3 is periodically updated to include that information.

  1. Synthesis, characterization and foaming of PHEA-PLLA, a new graft copolymer for biomedical engineering.

    Science.gov (United States)

    Carfì Pavia, Francesco; La Carrubba, Vincenzo; Brucato, Valerio; Palumbo, Fabio Salvatore; Giammona, Gaetano

    2014-08-01

    In this study a chemical grafting procedure was set up in order to link high molecular weight poly L-lactic acid (PLLA) chains to the hydrophilic α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) backbone. A graft copolymer named PHEA-g-PLLA (or simply PHEA-PLLA) was obtained bearing a degree of derivatization of 1.0 mol.% of PLLA as grafted chain. This new hybrid derivative offers both the opportune crystallinity necessary for the production of scaffolds trough a thermally induced phase separation (TIPS) technique and the proper chemical reactivity to perform further functionalizations with bio-effectors and drugs. PHEA-PLLA porous scaffolds for tissue engineering applications were successfully obtained via TIPS and characterized. Structures with an open porosity and a good level of interconnection were detected. As the applicability of the scaffold is mainly dependent on its pore size, preliminary studies about the mechanisms governing scaffold's pore diameter were carried out.

  2. Alginate/polyoxyethylene and alginate/gelatin hydrogels: preparation, characterization, and application in tissue engineering.

    Science.gov (United States)

    Aroguz, Ayse Z; Baysal, Kemal; Adiguzel, Zelal; Baysal, Bahattin M

    2014-05-01

    Hydrogels are attractive biomaterials for three-dimensional cell culture and tissue engineering applications. The preparation of hydrogels using alginate and gelatin provides cross-linked hydrophilic polymers that can swell but do not dissolve in water. In this work, we first reinforced pure alginate by using polyoxyethylene as a supporting material. In an alginate/PEO sample that contains 20 % polyoxyethylene, we obtained a stable hydrogel for cell culture experiments. We also prepared a stable alginate/gelatin hydrogel by cross-linking a periodate-oxidized alginate with another functional component such as gelatin. The hydrogels were found to have a high fluid uptake. In this work, preparation, characterization, swelling, and surface properties of these scaffold materials were described. Lyophilized scaffolds obtained from hydrogels were used for cell viability experiments, and the results were presented in detail.

  3. Experimental method to characterize the strain dependent permeability of tissue engineering scaffolds.

    Science.gov (United States)

    Nasrollahzadeh, Naser; Pioletti, Dominique P

    2016-11-07

    Permeability is an overarching mechanical parameter encompassing the effects of porosity, pore size, and interconnectivity of porous structures. This parameter directly influences transport of soluble particles and indirectly regulates fluid pressure and velocity in tissue engineering scaffolds. The permeability also contributes to the viscoelastic behavior of visco-porous material under loading through frictional drag mechanism. We propose a straightforward experimental method for permeability characterization of tissue engineering scaffolds. In the developed set-up a step-wise spacer was designed to facilitate measurement of the permeability under different compressive strains while maintaining similar experimental conditions during the successive measurements. As illustration of the method, we measured the permeability of scaffolds presenting different average pore sizes and subjected to different compression values. Results showed an exponential relationship between the permeability and the average pore size of the scaffolds. Furthermore, the trend of the permeability decrease with compressive strains was depending on pore sizes of the scaffolds. The permeability also appeared to play a role in relaxation behavior of the scaffolds.

  4. Preparation and characterization of 2,3-dialdehyde bacterial cellulose for potential biodegradable tissue engineering scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Li Jian; Wan Yizao [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Li Lianfeng [Technical Institute of Physics and Chemistry of CAS, Beijing 100080 (China); Liang Hui [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Wang Jiehua, E-mail: jiehuaw_tju@yahoo.com [School of Agriculture and Bioengineering, Tianjin University, Tianjin 300072 (China)

    2009-06-01

    Bacterial cellulose (BC) is suitable for applications as scaffolds in tissue engineering due to its unique properties. However, BC is not enzymatically degradable in vivo and this has become an essential limiting factor in its potential applications. In this work, BC was modified by periodate oxidation to give rise to a biodegradable 2,3-dialdehyde bacterial cellulose (DABC). After characterization by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, thin-film X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS), we demonstrated that the modified DABC nano-network was able to degrade into porous scaffold with micro-sized pores in water, phosphate buffered saline (PBS) and the simulated body fluid (SBF). The degradation process began from the oxidized amorphous part of the network and concurrently hydroxyapatite formed on the scaffold surface during the process in SBF. Our data also demonstrated that the tensile mechanical properties of the DABC nano-network were suitable for its use in tissue engineering scaffolds.

  5. Isolation and characterization of canine perivascular stem/stromal cells for bone tissue engineering.

    Science.gov (United States)

    James, Aaron W; Zhang, Xinli; Crisan, Mihaela; Hardy, Winters R; Liang, Pei; Meyers, Carolyn A; Lobo, Sonja; Lagishetty, Venu; Childers, Martin K; Asatrian, Greg; Ding, Catherine; Yen, Yu-Hsin; Zou, Erin; Ting, Kang; Peault, Bruno; Soo, Chia

    2017-01-01

    For over 15 years, human subcutaneous adipose tissue has been recognized as a rich source of tissue resident mesenchymal stem/stromal cells (MSC). The isolation of perivascular progenitor cells from human adipose tissue by a cell sorting strategy was first published in 2008. Since this time, the interest in using pericytes and related perivascular stem/stromal cell (PSC) populations for tissue engineering has significantly increased. Here, we describe a set of experiments identifying, isolating and characterizing PSC from canine tissue (N = 12 canine adipose tissue samples). Results showed that the same antibodies used for human PSC identification and isolation are cross-reactive with canine tissue (CD45, CD146, CD34). Like their human correlate, canine PSC demonstrate characteristics of MSC including cell surface marker expression, colony forming unit-fibroblast (CFU-F) inclusion, and osteogenic differentiation potential. As well, canine PSC respond to osteoinductive signals in a similar fashion as do human PSC, such as the secreted differentiation factor NEL-Like Molecule-1 (NELL-1). Nevertheless, important differences exist between human and canine PSC, including differences in baseline osteogenic potential. In summary, canine PSC represent a multipotent mesenchymogenic cell source for future translational efforts in tissue engineering.

  6. Fabrication and mechanical characterization of a polyvinyl alcohol sponge for tissue engineering applications.

    Science.gov (United States)

    Karimi, A; Navidbakhsh, M; Faghihi, S

    2014-05-01

    Polyvinyl alcohol (PVA) sponges are widely used for clinical applications, including ophthalmic surgical treatments, wound healing and tissue engineering. There is, however, a lack of sufficient data on the mechanical properties of PVA sponges. In this study, a biomechanical method is used to characterize the elastic modulus, maximum stress and strain as well as the swelling ratio of a fabricated PVA sponge (P-sponge) and it is compared with two commercially available PVA sponges (CENEFOM and EYETEC). The results indicate that the elastic modulus of the P-sponge is 5.32% and 13.45% lower than that of the CENEFOM and EYETEC sponges, while it bears 4.11% more and 10.37% less stress compared to the CENEFOM and EYETEC sponges, respectively. The P-sponge shows a maximum strain of 32% more than the EYETEC sponge as well as a 26.78% higher swelling ratio, which is a significantly higher absorbency compared to the CENEFOM. It is believed that the results of this study would help for a better understanding of the extension, rupture and swelling mechanism of PVA sponges, which could lead to crucial improvement in the design and application of PVA-based materials in ophthalmic and plastic surgeries as well as wound healing and tissue engineering.

  7. Engineered biochar from biofuel residue: characterization and its silver removal potential.

    Science.gov (United States)

    Yao, Ying; Gao, Bin; Wu, Feng; Zhang, Cunzhong; Yang, Liuyan

    2015-05-20

    A novel approach was used to prepare engineered biochar from biofuel residue (stillage from bagasse ethanol production) through slow pyrolysis. The obtained biochar was characterized for its physicochemical properties as well as silver sorption ability. Sorption experimental data showed that engineered biochar quickly and efficiently removed silver ion (Ag(+)) from aqueous solutions with a Langmuir maximum capacity of 90.06 mg/g. The high sorption of Ag(+) onto the biochar was attributed to both reduction and surface adsorption mechanisms. The reduction of Ag(+) by the biochar was confirmed with scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses of the postsorption biochar, which clearly showed the presence of metallic silver nanoparticles on the surface of the carbon matrix. An antimicrobial ability test indicated that silver-laden biochar effectively inhibited the growth of Escherichia coli, while the original biochar without silver nanoparticles promoted growth. Thus, biochar, prepared from biofuel residue materials, could be potentially applied not only to remove Ag(+) from aqueous solutions but also to produce a new value-added nanocomposite with antibacterial ability.

  8. Characterizing interdisciplinarity of researchers and research topics using web search engines.

    Directory of Open Access Journals (Sweden)

    Hiroki Sayama

    Full Text Available Researchers' networks have been subject to active modeling and analysis. Earlier literature mostly focused on citation or co-authorship networks reconstructed from annotated scientific publication databases, which have several limitations. Recently, general-purpose web search engines have also been utilized to collect information about social networks. Here we reconstructed, using web search engines, a network representing the relatedness of researchers to their peers as well as to various research topics. Relatedness between researchers and research topics was characterized by visibility boost-increase of a researcher's visibility by focusing on a particular topic. It was observed that researchers who had high visibility boosts by the same research topic tended to be close to each other in their network. We calculated correlations between visibility boosts by research topics and researchers' interdisciplinarity at the individual level (diversity of topics related to the researcher and at the social level (his/her centrality in the researchers' network. We found that visibility boosts by certain research topics were positively correlated with researchers' individual-level interdisciplinarity despite their negative correlations with the general popularity of researchers. It was also found that visibility boosts by network-related topics had positive correlations with researchers' social-level interdisciplinarity. Research topics' correlations with researchers' individual- and social-level interdisciplinarities were found to be nearly independent from each other. These findings suggest that the notion of "interdisciplinarity" of a researcher should be understood as a multi-dimensional concept that should be evaluated using multiple assessment means.

  9. Development and characterization of a full-thickness acellular porcine cornea matrix for tissue engineering.

    Science.gov (United States)

    Du, Liqun; Wu, Xinyi

    2011-07-01

    Our aim was to produce a natural, acellular matrix from porcine cornea for use as a scaffold in developing a tissue-engineered cornea replacement. Full-thickness, intact porcine corneas were decellularized by immersion in 0.5% (wt/vol) sodium dodecyl sulfate. The resulting acellular matrices were then characterized and examined specifically for completeness of the decellularization process. Histological analyses of decellularized corneal stromas showed that complete cell and α-Gal removal was achieved, while the major structural proteins including collagen type I and IV, laminin, and fibronectin were retained. DAPI staining did not detect any residual DNA within the matrix, and the DNA contents, which reflect the presence of cellular materials, were significantly diminished in the decellularized cornea. The collagen content of the decellularized cornea was well maintained compared with native tissues. Uniaxial tensile testing indicated that decellularization did not significantly compromise the ultimate tensile strength of the tissue (P > 0.05). In vitro cytotoxicity assays using rabbit corneal fibroblast cultures excluded the presence of soluble toxins in the biomaterial. In vivo implantation to rabbit interlamellar stromal pockets showed good biocompability. In summary, a full-thickness natural acellular matrix retaining the major structural components and strength of the cornea has been successfully developed. The matrix is biocompatible with cornea-derived cells and has potential for use in corneal transplantation and tissue-engineering applications. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  10. Characterizing interdisciplinarity of researchers and research topics using web search engines.

    Science.gov (United States)

    Sayama, Hiroki; Akaishi, Jin

    2012-01-01

    Researchers' networks have been subject to active modeling and analysis. Earlier literature mostly focused on citation or co-authorship networks reconstructed from annotated scientific publication databases, which have several limitations. Recently, general-purpose web search engines have also been utilized to collect information about social networks. Here we reconstructed, using web search engines, a network representing the relatedness of researchers to their peers as well as to various research topics. Relatedness between researchers and research topics was characterized by visibility boost-increase of a researcher's visibility by focusing on a particular topic. It was observed that researchers who had high visibility boosts by the same research topic tended to be close to each other in their network. We calculated correlations between visibility boosts by research topics and researchers' interdisciplinarity at the individual level (diversity of topics related to the researcher) and at the social level (his/her centrality in the researchers' network). We found that visibility boosts by certain research topics were positively correlated with researchers' individual-level interdisciplinarity despite their negative correlations with the general popularity of researchers. It was also found that visibility boosts by network-related topics had positive correlations with researchers' social-level interdisciplinarity. Research topics' correlations with researchers' individual- and social-level interdisciplinarities were found to be nearly independent from each other. These findings suggest that the notion of "interdisciplinarity" of a researcher should be understood as a multi-dimensional concept that should be evaluated using multiple assessment means.

  11. Tri-State Synfuels Project Review: Volume 12. Fluor project status. [Proposed Henderson, Kentucky coal to gasoline plant; engineering

    Energy Technology Data Exchange (ETDEWEB)

    1982-06-01

    The purpose of this report is to document and summarize activities associated with Fluor's efforts on the Tri-State Synfuels Project. The proposed facility was to be coal-to-transport fuels facility located in Henderson, Kentucky. Tri-State Synfuels Company was participating in the project as a partner of the US Department of Energy per terms of a Cooperative Agreement resulting from DOE's synfuel's program solicitation. Fluor's initial work plan called for preliminary engineering and procurement services to the point of commitment for construction for a Sasol Fischer-Tropsch plant. Work proceeded as planned until October 1981 when results of alternative coal-to-methanol studies revealed the economic disadvantage of the Synthol design for US markets. A number of alternative process studies followed to determine the best process configuration. In January 1982 Tri-State officially announced a change from Synthol to a Methanol to Gasoline (MTG) design basis. Further evaluation and cost estimates for the MTG facility eventually led to the conclusion that, given the depressed economic outlook for alternative fuels development, the project should be terminated. Official announcement of cancellation was made on April 13, 1982. At the time of project cancellation, Fluor had completed significant portions of the preliminary engineering effort. Included in this report are descriptions and summaries of Fluor's work during this project. In addition location of key project data and materials is identified and status reports for each operation are presented.

  12. Los Alamos National Laboratory Yucca Mountain Site Characterization Project 1992 quality program status report

    Energy Technology Data Exchange (ETDEWEB)

    Bolivar, S.L.; Burningham, A.; Chavez, P. [and others

    1994-03-01

    This status report summarizes the activities and accomplishments of the Los Alamos Yucca Mountain Site Characterization Project`s quality assurance program for calendar year 1992. The report includes major sections on Program Activities and Trend Analysis. Program Activities are discussed periodically at quality meetings. The most significant issue addressed in 1992 has been the timely revision of quality administrative procedures. The procedure revision process was streamlined from 55 steps to 7. The number of forms in procedures was reduced by 38%, and the text reduced by 29%. This allowed revision in 1992 of almost half of all implementing procedures. The time necessary to complete the revision process (for a procedure) was reduced from 11 months to 3 months. Other accomplishments include the relaxation of unnecessarily strict training requirements, requiring quality assurance reviews only from affected organizations, and in general simplifying work processes. All members of the YMP received training to the new Orientation class Eleven other training classed were held. Investigators submitted 971 records to the Project and only 37 were rejected. The software program has 115 programs approved for quality-affecting work. The Project Office conducted 3 audits and 1 survey of Los Alamos activities. We conducted 14 audits and 4 surveys. Eight corrective action reports were closed, leaving only one open. Internally, 22 deficiencies were recognized. This is a decrease from 65 in 1991. Since each deficiency requires about 2 man weeks to resolve, the savings are significant. Problems with writing acceptable deficiency reports have essentially disappeared. Trend reports for 1992 were examined and are summarized herein. Three adverse trends have been closed; one remaining adverse trend will be closed when the affected procedures are revised. The number of deficiencies issued to Los Alamos compared to other participants is minimal.

  13. Integrated geologic and engineering reservoir characterization of the Hutton Sandstone, Jackson region, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, D.S.; Holtz, M.H.; Yeh, J. [Univ. of Texas, Austin, TX (United States)] [and others

    1996-08-01

    An integrated geologic and engineering reservoir characterization study of the Hutton Sandstone was completed for the Jackson region, Eromanga Basin, Australia. Our approach involves four principal steps: (1) determine reservoir architecture within a high-resolution sequence stratigraphic framework, (2) investigate trends in reservoir fluid flow, (3) integrate fluid flow trends with reservoir architecture to identify fundamental reservoir heterogeneities, and (4) identify opportunities for reserve growth. Contrary to the existing perception, the Hutton Sandstone, a continental-scale bed-load fluvial system, does not behave as a large, homogeneous tank in which pistonlike displacement of produced oil occurs unimpeded by vertical migration of the aquifer. The sequence stratigraphic analysis identified numerous thin but widespread shale units, deposited during lacustrine flooding events that periodically interrupted episodes of coarse clastic Hutton deposition. These shales represent chronostratigraphically significant surfaces. More importantly, the trends established in reservoir fluid flow from monitoring aquifer encroachment, production response to water shut-off workovers, and differential depletion in Repeat Formation Tests indicate that these shale units act as efficient barriers to vertical fluid flow. Erosion of the upper part of the Hutton reservoir by the younger Birkhead mixed-load fluvial system caused further stratigraphic complexity and introduced additional barriers to vertical and lateral migration of mobile oil and aquifer encroachment. This integrated characterization targeted strategic infill and step-out drilling and recompletion candidates.

  14. Production and characterization of engineered alginate-based microparticles containing ECM powder for cell/tissue engineering applications.

    Science.gov (United States)

    Mazzitelli, Stefania; Luca, Giovanni; Mancuso, Francesca; Calvitti, Mario; Calafiore, Riccardo; Nastruzzi, Claudio; Johnson, Scott; Badylak, Stephen F

    2011-03-01

    A method for the production of engineered alginate-based microparticles, containing extracellular matrix and neonatal porcine Sertoli cells (SCs), is described. As a source for extracellular matrix, a powder form of isolated and purified urinary bladder matrix (UBM) was employed. We demonstrated that the incorporation of UBM does not significantly alter the morphological and dimensional characteristics of the microparticles. The alginate microparticles were used for SC encapsulation as an immunoprotective barrier for transplant purposes, while the co-entrapped UBM promoted retention of cell viability and function. These engineered microparticles could represent a novel approach to enhancing immunological acceptance and increasing the functional life-span of the entrapped cells for cell/tissue engineering applications. In this respect, it is noteworthy that isolated neonatal porcine SCs, administered alone in highly biocompatible microparticles, led to diabetes prevention and reversion in nonobese diabetic (NOD) mice.

  15. Changes in seed water status as characterized by NMR in developing soybean seed grown under moisture stress conditions

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, P., E-mail: pkrishnan@iari.res.in; Singh, Ravender; Verma, A.P.S.; Joshi, D.K.; Singh, Sheoraj

    2014-02-21

    Highlights: • In developing soybean seeds, moisture stress resulted in more proportion of water to bound state. • These changes are further corroborated by concomitant changes in seed metabolites. • Thus there exists a moisture stress and development stage dependence of seed tissue water status. - Abstract: Changes in water status of developing seeds of Soybean (Glycine max L. Merrill.) grown under different moisture stress conditions were characterized by proton nuclear magnetic resonance (NMR)- spin–spin relaxation time (T{sub 2}). A comparison of the seed development characteristics, composition and physical properties indicated that, characteristics like seed weight, seed number/ear, rate of seed filling increased with development stages but decreased with moisture stress conditions. The NMR- spin–spin relaxation (T{sub 2}) component like bound water increased with seed maturation (40–50%) but decreased with moisture stress conditions (30–40%). The changes in seed water status to increasing levels of moisture stress and seed maturity indicates that moisture stress resulted in more proportion of water to bound state and intermediate state and less proportion of water in free-state. These changes are further corroborated by significant changes in protein and starch contents in seeds under high moisture stress treatments. Thus seed water status during its development is not only affected by development processes but also by moisture stress conditions. This study strongly indicated a clear moisture stress and development stage dependence of seed tissue water status in developing soybean seeds.

  16. Synthesis and characterization of a novel chitosan/montmorillonite/hydroxyapatite nanocomposite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Katti, Kalpana S; Katti, Dinesh R; Dash, Rajalaxmi [Department of Civil Engineering, North Dakota State University, Fargo, ND 58105 (United States)], E-mail: Kalpana.katti@ndsu.edu

    2008-09-01

    Recently, biopolymer-based nanocomposites have been replacing synthetic polymer composites for various biomedical applications. This is often because of the biocompatible and biodegradable behavior of natural polymers. Several studies have been reported pertaining to the synthesis and characterization of chitosan(chi)/montmorillonite(MMT) and chitosan (chi)/hydroxyapatite (HAP) for tissue engineering applications. In the present work, a biopolymer-based novel nanocomposite chitosan/montmorillonite (MMT)/hydroxyapatite (HAP) was developed for biomedical applications. The composite was prepared from chitosan, unmodified MMT and HAP precipitate in aqueous media. The properties of the composites were investigated using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). Nanomechanical properties were measured using nanoindentation. Cell culture experiments were also conducted in order to ascertain the biocompatibility of the composite. The XRD results indicate that an intercalated structure was formed with an increase in d-spacing of montmorillonite. FTIR studies provide the evidence of molecular interaction among the three different constituents of the composite. AFM images show well-distributed nanoparticles in the chitosan matrix. The composites also exhibit a significant enhancement in nanomechanical property as compared to pure chitosan as well as the chi/HAP and chi/MMT composites. The TGA results indicate that an intercalated nanocomposite was formed with improved thermal properties even compared to chi/MMT composites. The results of cell culture experiments show that the composite is biocompatible and has a better cell proliferation rate compared to chi/HAP composites. This work represents the design of a novel clay-chitosan-hydroxyapatite composite with improved mechanical properties that has potential applications in bone tissue engineering.

  17. Synthesis and characterization of CaO-loaded electrospun matrices for bone tissue engineering.

    Science.gov (United States)

    Münchow, Eliseu A; Pankajakshan, Divya; Albuquerque, Maria T P; Kamocki, Krzysztof; Piva, Evandro; Gregory, Richard L; Bottino, Marco C

    2016-11-01

    This study aims to synthesize and characterize biodegradable polymer-based matrices loaded with CaO nanoparticles for osteomyelitis treatment and bone tissue engineering. Poly(ε-caprolactone) (PCL) and PCL/gelatin (1:1, w/w) solutions containing CaO nanoparticles were electrospun into fibrous matrices. Scanning (SEM) and transmission (TEM) electron microscopy, Fourier transformed infrared (FTIR), energy dispersive X-ray spectroscopy (EDS), contact angle (CA), tensile testing, and antibacterial activity (agar diffusion assay) against Staphylococcus aureus were performed. Osteoprecursor cell (MC3T3-E1) response (i.e., viability and alkaline phosphatase expression/ALP) and infiltration into the matrices were evaluated. CaO nanoparticles were successfully incorporated into the fibers, with the median fiber diameter decreasing after CaO incorporation. The CA decreased with the addition of CaO, and the presence of gelatin made the matrix very hydrophilic (CA = 0°). Increasing CaO concentrations progressively reduced the mechanical properties (p ≤ 0.030). CaO-loaded matrices did not display consistent antibacterial activity. MC3T3-E1 cell viability demonstrated the highest levels for CaO-loaded matrices containing gelatin after 7 days in culture. An increased ALP expression was consistently seen for PCL/CaO matrices when compared to PCL and gelatin-containing counterparts. Despite inconsistent antibacterial activity, CaO nanoparticles can be effectively loaded into PCL or PCL/gelatin fibers without negatively affecting the overall performance of the matrices. More importantly, CaO incorporation enhanced cell viability as well as differentiation capacity, as demonstrated by an increased ALP expression. CaO-loaded electrospun matrices show potential for applications in bone tissue engineering.

  18. Thermal compression and characterization of three-dimensional nonwoven PET matrices as tissue engineering scaffolds.

    Science.gov (United States)

    Li, Y; Ma, T; Yang, S T; Kniss, D A

    2001-03-01

    Nonwoven fibrous matrices have been widely used as scaffolds in tissue engineering, and modification of microstructure of these matrices is needed to organize cells in three-dimensional space with spatially balanced proliferation and differentiation required for functional tissue development. The method of thermal compression of nonwoven polyethylene terephthalate (PET) fabrics was developed and key parameters of temperature, pressure, and compression duration were evaluated in this study. The permanent deformation was obtained at elevated temperature under pressure and the viscoelastic compressional behaviors were observed, characterized by a distinct apparent modulus change in glass transition temperature region. A liquid extrusion method was further employed to analyze both pore size and its distribution for matrices with porosity ranging from 84 to 93%. It is also found that a more uniformly distributed pore size was resulted from thermal compression and the isotropic nature of nonwoven fabrics was preserved because of the proportional reduction of the pore by compression. The thermally compressed fabric matrices with two different pore sizes (15 and 20 microm in pore radius) were used to culture human trophoblast ED27 and NIH 3T3 cells. It was found that cells cultured in the different pore-size PET matrices had different cell spatial organization and proliferation rates. The smaller pores in the matrix allowed cells to spread better and proliferate faster, while cells in the larger pores tended to form large aggregates and had lower proliferation rate. The thermal compression technique also can be applied to other synthetic fibrous matrices including biodegradable polymers used in tissue engineering to modify the microstructure according to their viscoelastic properties.

  19. Electrochemical preparation and characterization of PNIPAM-HAp scaffolds for bone tissue engineering.

    Science.gov (United States)

    Ribeiro, Charlene Aparecida; Martins, Marcos Vinicius Surmani; Bressiani, Ana Helena; Bressiani, José Carlos; Leyva, Maria Elena; de Queiroz, Alvaro Antonio Alencar

    2017-12-01

    In the last decade, a variety of methods for fabrication of three-dimensional biomimetic scaffolds based on hydrogels have been developed for tissue engineering. However, many methods require the use of catalysts which compromises the biocompatibility of the scaffolds. The electrochemical polymerization (ECP) of acrylic monomers has received an increased attention in recent years due to its versatility in the production of highly biocompatible coatings for the electrodes used in medical devices. The main aim of this work was the use of ECP as scaffold fabrication technique to produce highly porous poly(N-isopropylacrylamide) (PNIPAM)/hydroxyapatite (HAp) composite for bone tissue regeneration. The prepared PNIPAM-HAp porous scaffolds were characterized by SEM, FTIR, water swelling, porosity measurements and X-ray diffraction (XRD) techniques. FTIR indicates that ECP promotes a successful conversion of NIPAM to PNIPAM. The water swelling and porosity were shown to be controlled by the HAp content in PNIPAM-HAp scaffolds. The PNIPAM-HAp scaffolds exhibited no cytotoxicity to MG63 cells, showing that ECP are potentially useful for the production of PNIPAM-HAp scaffolds. To address the osteomyelitis, a significant complication in orthopedic surgeries, PNIPAM-HAp scaffolds were loaded with the antibiotic oxacillin. The oxacillin release and the bacterial killing activity of the released oxacillin from PNIPAM-HAp against S. aureus and P. aeruginosa were demonstrated. These observations demonstrate that ECP are promising technique for the production of non-toxic, biocompatible PNIPAM-HAp scaffolds for tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Relaxor-based ferroelectric single crystals: growth, domain engineering, characterization and applications

    Science.gov (United States)

    Sun, Enwei; Cao, Wenwu

    2014-01-01

    techniques, domain engineering concept, and full-matrix property characterization all the way to device innovations. It outlines a truly encouraging story in materials science in the modern era. All key references are provided and 30 complete sets of material parameters for different types of relaxor-PT single crystals are listed in the Appendix. It is the intension of this review article to serve as a resource for those who are interested in basic research and practical applications of these relaxor-PT single crystals. In addition, possible mechanisms of giant piezoelectric properties in these domain-engineered relaxor-PT systems will be discussed based on contributions from polarization rotation and charged domain walls. PMID:25061239

  1. Relaxor-based ferroelectric single crystals: growth, domain engineering, characterization and applications.

    Science.gov (United States)

    Sun, Enwei; Cao, Wenwu

    2014-08-01

    techniques, domain engineering concept, and full-matrix property characterization all the way to device innovations. It outlines a truly encouraging story in materials science in the modern era. All key references are provided and 30 complete sets of material parameters for different types of relaxor-PT single crystals are listed in the Appendix. It is the intension of this review article to serve as a resource for those who are interested in basic research and practical applications of these relaxor-PT single crystals. In addition, possible mechanisms of giant piezoelectric properties in these domain-engineered relaxor-PT systems will be discussed based on contributions from polarization rotation and charged domain walls.

  2. Characterization of Gas-Phase Organics Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry: Aircraft Turbine Engines.

    Science.gov (United States)

    Kilic, Dogushan; Brem, Benjamin T; Klein, Felix; El-Haddad, Imad; Durdina, Lukas; Rindlisbacher, Theo; Setyan, Ari; Huang, Rujin; Wang, Jing; Slowik, Jay G; Baltensperger, Urs; Prevot, Andre S H

    2017-03-17

    Nonmethane organic gas emissions (NMOGs) from in-service aircraft turbine engines were investigated using a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) at an engine test facility at Zurich Airport, Switzerland. Experiments consisted of 60 exhaust samples for seven engine types (used in commercial aviation) from two manufacturers at thrust levels ranging from idle to takeoff. Emission indices (EIs) for more than 200 NMOGs were quantified, and the functional group fractions (including acids, carbonyls, aromatics, and aliphatics) were calculated to characterize the exhaust chemical composition at different engine operation modes. Total NMOG emissions were highest at idling with an average EI of 7.8 g/kg fuel and were a factor of ∼40 lower at takeoff thrust. The relative contribution of pure hydrocarbons (particularly aromatics and aliphatics) of the engine exhaust decreased with increasing thrust while the fraction of oxidized compounds, for example, acids and carbonyls increased. Exhaust chemical composition at idle was also affected by engine technology. Older engines emitted a higher fraction of nonoxidized NMOGs compared to newer ones. Idling conditions dominated ground level organic gas emissions. Based on the EI determined here, we estimate that reducing idle emissions could substantially improve air quality near airports.

  3. Petrofacies Analysis - A Petrophysical Tool for Geologic/Engineering Reservoir Characterization

    Science.gov (United States)

    Watney, W.L.; Guy, W.J.; Doveton, J.H.; Bhattacharya, S.; Gerlach, P.M.; Bohling, G.C.; Carr, T.R.

    1998-01-01

    Petrofacies analysis is defined as the characterization and classification of pore types and fluid saturations as revealed by petrophysical measurements of a reservoir. The word "petrofacies" makes an explicit link between petroleum engineers' concerns with pore characteristics as arbiters of production performance and the facies paradigm of geologists as a methodology for genetic understanding and prediction. In petrofacies analysis, the porosity and resistivity axes of the classical Pickett plot are used to map water saturation, bulk volume water, and estimated permeability, as well as capillary pressure information where it is available. When data points are connected in order of depth within a reservoir, the characteristic patterns reflect reservoir rock character and its interplay with the hydrocarbon column. A third variable can be presented at each point on the crossplot by assigning a color scale that is based on other well logs, often gamma ray or photoelectric effect, or other derived variables. Contrasts between reservoir pore types and fluid saturations are reflected in changing patterns on the crossplot and can help discriminate and characterize reservoir heterogeneity. Many hundreds of analyses of well logs facilitated by spreadsheet and object-oriented programming have provided the means to distinguish patterns typical of certain complex pore types (size and connectedness) for sandstones and carbonate reservoirs, occurrences of irreducible water saturation, and presence of transition zones. The result has been an improved means to evaluate potential production, such as bypassed pay behind pipe and in old exploration wells, or to assess zonation and continuity of the reservoir. Petrofacies analysis in this study was applied to distinguishing flow units and including discriminating pore type as an assessment of reservoir conformance and continuity. The analysis is facilitated through the use of colorimage cross sections depicting depositional sequences

  4. Processing and characterization of chitosan/PVA and methylcellulose porous scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Kanimozhi, K. [Department of Chemistry, Auxilium College, Vellore 632 006 (India); Khaleel Basha, S. [Department of Biochemistry, C. Abdul Hakeem College, Melvisharam 632 509 (India); Sugantha Kumari, V., E-mail: sheenasahana04@gmail.com [Department of Chemistry, Auxilium College, Vellore 632 006 (India)

    2016-04-01

    Biomimetic porous scaffold chitosan/poly(vinyl alcohol) CS/PVA containing various amounts of methylcellulose (MC) (25%, 50% and 75%) incorporated in CS/PVA blend was successfully produced by a freeze drying method in the present study. The composite porous scaffold membranes were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), swelling degree, porosity, degradation of films in Hank's solution and the mechanical properties. Besides these characterizations, the antibacterial activity of the prepared scaffolds was tested, toward the bacterial species Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). FTIR, XRD and DSC demonstrated that there was strong intermolecular hydrogen bonding between the molecules of CS/PVA and MC. The crystalline microstructure of the scaffold membranes was not well developed. SEM images showed that the morphology and diameter of the scaffolds were mainly affected by the weight ratio of MC. By increasing the MC content in the hybrid scaffolds, their swelling capacity and porosity increased. The mechanical properties of these scaffolds in dry and swollen state were greatly improved with high swelling ratio. The elasticity of films was also significantly improved by the incorporation of MC, and the scaffolds could also bear a relative high tensile strength. These findings suggested that the developed scaffold possess the prerequisites and can be used as a scaffold for tissue engineering. - Highlights: • The porous scaffolds of CS/PVA containing different MC contents were fabricated. • Addition of MC improved the compatibility between CS and PVA. • The mechanical properties of these scaffolds were greatly improved with high swelling ratio. • Biocompatibility test showed that the different MC content scaffolds had no cytotoxicity.

  5. Petrofacies analysis - the petrophysical tool for geologic/engineering reservoir characterization

    Energy Technology Data Exchange (ETDEWEB)

    Watney, W.L.; Guy, W.J.; Gerlach, P.M. [Kansas Geological Survey, Lawrence, KS (United States)] [and others

    1997-08-01

    Petrofacies analysis is defined as the characterization and classification of pore types and fluid saturations as revealed by petrophysical measures of a reservoir. The word {open_quotes}petrofacies{close_quotes} makes an explicit link between petroleum engineers concerns with pore characteristics as arbiters of production performance, and the facies paradigm of geologists as a methodology for genetic understanding and prediction. In petrofacies analysis, the porosity and resistivity axes of the classical Pickett plot are used to map water saturation, bulk volume water, and estimated permeability, as well as capillary pressure information, where it is available. When data points are connected in order of depth within a reservoir, the characteristic patterns reflect reservoir rock character and its interplay with the hydrocarbon column. A third variable can be presented at each point on the crossplot by assigning a color scale that is based on other well logs, often gamma ray or photoelectric effect, or other derived variables. Contrasts between reservoir pore types and fluid saturations will be reflected in changing patterns on the crossplot and can help discriminate and characterize reservoir heterogeneity. Many hundreds of analyses of well logs facilitated by spreadsheet and object-oriented programming have provided the means to distinguish patterns typical of certain complex pore types for sandstones and carbonate reservoirs, occurrences of irreducible water saturation, and presence of transition zones. The result has been an improved means to evaluate potential production such as bypassed pay behind pipe and in old exploration holes, or to assess zonation and continuity of the reservoir. Petrofacies analysis is applied in this example to distinguishing flow units including discrimination of pore type as assessment of reservoir conformance and continuity. The analysis is facilitated through the use of color cross sections and cluster analysis.

  6. Characterization Data Package for Containerized Sludge Samples Collected from Engineered Container SCS-CON-210

    Energy Technology Data Exchange (ETDEWEB)

    Fountain, Matthew S.; Fiskum, Sandra K.; Baldwin, David L.; Daniel, Richard C.; Bos, Stanley J.; Burns, Carolyn A.; Carlson, Clark D.; Coffey, Deborah S.; Delegard, Calvin H.; Edwards, Matthew K.; Greenwood, Lawrence R.; Neiner, Doinita; Oliver, Brian M.; Pool, Karl N.; Schmidt, Andrew J.; Shimskey, Rick W.; Sinkov, Sergey I.; Snow, Lanee A.; Soderquist, Chuck Z.; Thompson, Christopher J.; Trang-Le, Truc LT; Urie, Michael W.

    2013-09-10

    This data package contains the K Basin sludge characterization results obtained by Pacific Northwest National Laboratory during processing and analysis of four sludge core samples collected from Engineered Container SCS-CON-210 in 2010 as requested by CH2M Hill Plateau Remediation Company. Sample processing requirements, analytes of interest, detection limits, and quality control sample requirements are defined in the KBC-33786, Rev. 2. The core processing scope included reconstitution of a sludge core sample distributed among four to six 4-L polypropylene bottles into a single container. The reconstituted core sample was then mixed and subsampled to support a variety of characterization activities. Additional core sludge subsamples were combined to prepare a container composite. The container composite was fractionated by wet sieving through a 2,000 micron mesh and a 500-micron mesh sieve. Each sieve fraction was sampled to support a suite of analyses. The core composite analysis scope included density determination, radioisotope analysis, and metals analysis, including the Waste Isolation Pilot Plant Hazardous Waste Facility Permit metals (with the exception of mercury). The container composite analysis included most of the core composite analysis scope plus particle size distribution, particle density, rheology, and crystalline phase identification. A summary of the received samples, core sample reconstitution and subsampling activities, container composite preparation and subsampling activities, physical properties, and analytical results are presented. Supporting data and documentation are provided in the appendices. There were no cases of sample or data loss and all of the available samples and data are reported as required by the Quality Assurance Project Plan/Sampling and Analysis Plan.

  7. A novel characterization of organic molecular crystal structures for the purpose of crystal engineering.

    Science.gov (United States)

    Thomas, Noel W

    2015-08-01

    A novel analytical approach is proposed for the characterization of organic molecular crystal structures where close packing is an important factor. It requires the identification of a unique reference axis within the crystal, along which three-dimensional space is divided into close-packed blocks (CPB) and junction zones (JZ). The degree of close packing along the reference axis is quantified by a two-dimensional packing function, ϕ2D, of symmetry determined by the space group. Values of ϕ2D reflect the degree of area-filling in planes perpendicular to this axis. The requirement of close packing within CPB allows the planar structures perpendicular to the reference axis to be analysed as tessellations of area-filling molecular-based cells (MBC), which are generally hexagonal. The form of these cells reflects the molecular shape in the cross-section, since their vertices are given by the centres of the voids between molecules. There are two basic types of MBC, Type 1, of glide or pseudo-glide symmetry, and Type 2, which is formed by lattice translations alone and generally requires a short unit-cell axis. MBC at layers of special symmetry are used to characterize the structures in terms of equivalent ellipses with parameters aell, bell and χell. The ratio aell/bell allows the established α, β, γ classification to be integrated into the current framework. The values of parameters aell and bell arising from all the structures considered, polynuclear aromatic hydrocarbons (PAH), substituted anthracenes and anthraquinones (SAA) and 2-benzyl-5-benzylidene (BBCP) are mapped onto a universal curve. The division of three-dimensional space into CPB and JZ is fundamentally useful for crystal engineering, since the structural perturbations brought about by substitution at hydrogen positions located within JZ are minimal. A contribution is also made to ongoing debate concerning the adoption of polar space groups, isomorphism and polymorphism.

  8. A plume capture technique for the remote characterization of aircraft engine emissions.

    Science.gov (United States)

    Johnson, G R; Mazaheri, M; Ristovski, Z D; Morawska, L

    2008-07-01

    A technique for capturing and analyzing plumes from unmodified aircraft or other combustion sources under real world conditions is described and applied to the task of characterizing plumes from commercial aircraft during the taxiing phase of the Landing/Take-Off (LTO) cycle. The method utilizes a Plume Capture and Analysis System (PCAS) mounted in a four-wheel drive vehicle which is positioned in the airfield 60 to 180 m downwind of aircraft operations. The approach offers low test turnaround times with the ability to complete careful measurements of particle and gaseous emission factors and sequentially scanned particle size distributions without distortion due to plume concentration fluctuations. These measurements can be performed for individual aircraft movements at five minute intervals. A Plume Capture Device (PCD) collected samples of the naturally diluted plume in a 200 L conductive membrane conforming to a defined shape. Samples from over 60 aircraft movements were collected and analyzed in situ for particulate and gaseous concentrations and for particle size distribution using a Scanning Particle Mobility Sizer (SMPS). Emission factors are derived for particle number, NO(x), and PM2.5 for a widely used commercial aircraft type, Boeing 737 airframes with predominantly CFM56 class engines, during taxiing. The practical advantages of the PCAS include the capacity to perform well targeted and controlled emission factor and size distribution measurements using instrumentation with varying response times within an airport facility, in close proximity to aircraft during their normal operations.

  9. Characterization of Synthetic GTL Jet Fuel for use in Gas Turbine Engines

    Science.gov (United States)

    Sadr, Reza; Kannaiyan, Kumaran

    2010-11-01

    Stringent emission regulations have instigated the search for alternative-clean source of energy. Recently, Gas-to-Liquid (GTL) fuel has grabbed the global attention by its clean combustion characteristics owing to the absence of aromatics and Sulphur. However, this will introduce potential risks and benefits. Last fall Qatar airways has proven the feasibility of using GTL as a potential alternative clean fuel by a 3200 mile flight using a fuel blend of 50% JetA + 50% GTL. Researchers from Texas A & M University at Qatar (TAMUQ) in collaboration with their counterparts in Rolls-Royce (RR), UK, and German Aerospace Laboratory (DLR) are in a joint effort to establish an in-depth characterization of the combustion performance of GTL fuel in gas turbine engines. In TAMUQ, the research focus is to investigate the spray characteristics of GTL fuels. The results will be compared with that of standard fuel and correlate with combustion results to gain insights on GTL performance. This will help designers to optimize the nozzle geometry to improve the combustor performance. The objective of this talk is to introduce this ongoing effort and to discuss the experimental facility and preliminary results.

  10. Distortion Optimization of Engine Cylinder Liner Using Spectrum Characterization and Parametric Analysis

    Directory of Open Access Journals (Sweden)

    Zhaohui Yang

    2016-01-01

    Full Text Available In an automotive powertrain system, the cylinder liner is one of the most critical components which possesses the intricate structural configurations coupled with complex pattern of various operational loads. This paper attempts to develop a concrete and practical procedure for the optimization of cylinder liner distortion for achieving future requirements regarding exhaust emissions, fuel economy, and oil consumptions. First, numerical calculation based on finite element method (FEM and computational fluid dynamics (CFD is performed to capture the mechanism of cylinder liner distortion under actual engine operation conditions. Then, a spectrum analysis approach is developed to describe the distribution characteristic of operational loads (thermal and mechanical around the circumference of a distorted cylinder bore profile; the FFT procedure provides an efficient way to implement this calculation. With this approach, a relationship between the dominant order of distortion and special operational load is obtained; the design features which are critically relative to cylinder liner distortion are also identified through spectrum analysis. After characterizing the variation tendency of each dominant order of distortion through parametric analysis, a new design scheme is established to implement the distortion optimization. Simulation results indicate that a much better solution is obtained by using the proposed scheme.

  11. 浅谈建筑工程招投标市场现状%Discussion on the status of market of inviting and submitting of building engineering

    Institute of Scientific and Technical Information of China (English)

    王燕军

    2009-01-01

    Through investigating and analyzing the market of inviting and subraitting of building engineering, the problems existing in present market of inviting and submitting of building engineering were generalized, the principle reasons of the phenomena were studied, the counter-measures to improve and complete market status of inviting and submitting of building engineering were proposed, so as to better standard building market order.%通过对建筑工程招投标市场的调查分析,归纳了当前建筑工程招投标市场存在的问题,研究了存在这些现象的主要原因,并提出了改进和完善建筑工程招投标市场现状的对策,从而更好地规范建筑市场秩序.

  12. Non destructive characterization of cracks in concrete by ultrasonic auscultation of civil engineering structures

    Energy Technology Data Exchange (ETDEWEB)

    Quiviger, A.; Payan, C.; Chaix, J.F.; Zardan, J.P.; Garnier, V. [EDF, LCND (France); Salin, J. [EDF Paris (France)

    2011-07-01

    Concrete Non Destructive Characterisation is one of the important issues to evaluate the life duration in the present and future civil engineering structures. The damaging modes of the structures often imply the phases of the appearance and after growth of the cracks. We have to detect, identify and characterize them. The characterization result must lead to a diagnosis of the criticality of a crack regarding to the integrity of the structure and its ability to fulfill its function. The Non Destructive Evaluation techniques are numerous but the ultrasonic ones are able to give an answer to both the characterization and the follow-up of the defect on site. Yet if this method is potentially relevant to detect and identify the cracks in the concrete, we have today a certain amount of locks to remove in order to offer robust and reproducible industrial solutions. These locks range from research points like the description of the real propagation of linear or non linear ultrasonic waves in a heterogeneous material, to more industrial concepts such as the development of devices designed to be applied in the concrete control. For this purpose, we present our latest works on this topic. We develop an overview of the problem: first, to extract the most important theoretical solutions to analyse an unstopping and closed crack in concrete with an only one face access. Then we suggest a methodology to apply one of these solutions on site. A first step of this work after having chosen a solution is to check the ability of the technique to detect a crack, and its sensitivity to the length, depth and opening of the crack. We have developed an experimental plan based on theoretical concept to compare the linear and non linear survey on a set of specimens composed of concrete beams cracked to different depths. We describe the devices and give the latest results. The non linear technique is able to extract information on the size of the cracks. It is an important step to progress in

  13. Synthesis and characterization of polyglycerols dendrimers for applications in tissue engineering biological

    Energy Technology Data Exchange (ETDEWEB)

    Passos, E.D.; Queiroz, A.A.A. de [Universidade Federal de Itajuba (UNIFEI), MG (Brazil)

    2014-07-01

    Full text: Introduction: Over the last twenty years is the growing development in the manufacture of synthetic scaffold in tissue engineering applications. These new materials are based on polyglycerol dendrimers (PGLD's). PGLD's are highly functional polymers with hydroxymethyl side groups, fulfill all structural prerequisites to replace poly(ethylene glycol)s in medical applications. Furthermore, since these materials are based on naturally occurring compounds that degrades over time in the body and can be safely excreted. The objective of this work was the synthesis, physicochemical, biological characterization of HPGL's with potential use as scaffolds in tissue engineering. HPGL's with oligomeric cores, of diglycerol triglycerol and tetraglycerol was used. Theoretical and Experimental Simulation Details: The synthesis of PGLD procedures involves the etherification of glycerol through anionic polymerization of glycidol. The PGLD's were characterized by chromatographic techniques (SEC and HPLC), spectroscopic (FTIR, 1H-NMR and 13C - NMR) electrochemical (zeta potential) and thermal analysis (DSC and TGA) techniques. The structure- activity relationships (SAR's) of compound prototype and its analogs were studied to determine the generation number (G) of the molecule responsible for the biological activity on the adhesion and cell proliferation process. A detailed study of the structure of PGLD's of G=0-4 was performed using the Hyperchem 7. 5 and Gromacs 4 software packages. The biocompatibility studies were studied by scanning electron microscopy (SEM) and fluorescence microscopy (EPF) technique after PGLD (G=0-4) blood contact. The overall electro-negativity/total charge density, dipole moment, frontier orbital's (HOMO - LUMO) and electrostatic potential maps (EPM) were calculated. The most stable form of the resulting compounds was determined by estimating the hydration energy and energy conformation. Results and

  14. Cross Sectional Characterization of Factors Associated with Pediatric HIV Status Disclosure in Southern Ethiopia.

    Directory of Open Access Journals (Sweden)

    Birkneh Tilahun Tadesse

    Full Text Available Disclosure of HIV positive status to children and adolescents is a complex process. However, disclosure has been found to be associated with improved outcomes. The objective of the current study was to identify the predictors that facilitate disclosure of HIV status to children and adolescents and to study the reasons for non-disclosure.Interviews of caregivers and reviews of records were done to collect data on caregiver and child information and details regarding the disclosure status of children. Bivariate analysis was done to test the association between HIV status disclosure and different caregiver and child factors. To identify the independent predictors of disclosure, we did multivariable logistic regression.A total of 177 children attending an HIV clinic were included. The mean age of the participants was 10.1 years (SD = 2.8, and about half (50.8% were female. Most caregivers, 137 (77.8% stated that disclosure of HIV status to children is important and should be done. However, disclosure had only been made to 59 (33.3% of the participants. Child age more than 10 years [AOR = 6.7; 95%CI: 1.73-26.01], duration of HIV diagnosis of 5 years or more [AOR = 4.4; 95%CI: 1.26-15.06] and taking a zidovudin (AZT based regimen [AOR = 3.5; 95%CI: 1.31-9.53] predicted HIV positive status disclosure. Additionally, length of treatment of caregivers of more than 14 years [AOR = 3.9; 95%CI: 1.07-14.61], disclosure of caregiver's HIV status to children and/or others [AOR = 4.7; 95%CI: 1.19-18.74], and the child's inquiry about their condition [AOR = 4.5; 95%CI: 1.16-17.43] increased the odds of disclosure.The rate of disclosure among HIV infected children in southern Ethiopia is low. Primarily time-based factors were associated with the probability of HIV positive status disclosure and a specific regimen which has not been found previously. Further qualitative research may elucidate more on these factors; educational strategies may address some of these

  15. Characterization Of Superconducting Samples With SIC System For Thin Film Developments: Status And Recent Results

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, H. Lawrence [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Valente-Feliciano, Anne-Marie [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Xiao, Binping [Brookhaven National Lab, Upton, NY (United States); Eremeev, Grigory V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-02-01

    Within any thin film development program directed towards SRF accelerating structures, there is a need for an RF characterization device that can provide information about RF properties of small samples. The current installation of the RF characterization device at Jefferson Lab is Surface Impedance Characterization (SIC) system. The data acquisition environment for the system has recently been improved to allow for automated measurement, and the system has been routinely used for characterization of bulk Nb, films of Nb on Cu, MgB{sub 2}, NbTiN, Nb{sub 3}Sn films, etc. We present some of the recent results that illustrate present capabilities and limitations of the system.

  16. The pipeline still leaks and more than you think: a status report on gender diversity in biomedical engineering.

    Science.gov (United States)

    Chesler, Naomi C; Barabino, Gilda; Bhatia, Sangeeta N; Richards-Kortum, Rebecca

    2010-05-01

    While the percentage of women in biomedical engineering is higher than in many other technical fields, it is far from being in proportion to the US population. The decrease in the proportion of women and underrepresented minorities in biomedical engineering from the bachelors to the masters to the doctoral levels is evidence of a still leaky pipeline in our discipline. In addition, the percentage of women faculty members at the assistant, associate and full professor levels remain disappointingly low even after years of improved recruitment of women into biomedical engineering at the undergraduate level. Worse, the percentage of women graduating with undergraduate degrees in biomedical engineering has been decreasing nationwide for the most recent three year span for which national data are available. Increasing diversity in biomedical engineering is predicted to have significant research and educational benefits. The barriers to women's success in biomedical engineering and strategies for overcoming these obstacles-and fixing the leaks in the pipeline-are reviewed.

  17. Analysis of uncertainty and variability in finite element computational models for biomedical engineering:characterization and propagation

    Directory of Open Access Journals (Sweden)

    Nerea Mangado

    2016-11-01

    Full Text Available Computational modeling has become a powerful tool in biomedical engineering thanks to its potential to simulate coupled systems. However, real parameters are usually not accurately known and variability is inherent in living organisms. To cope with this, probabilistic tools, statistical analysis and stochastic approaches have been used. This article aims to review the analysis of uncertainty and variability in the context of finite element modeling in biomedical engineering. Characterization techniques and propagation methods are presented, as well as examples of their applications in biomedical finite element simulations. Uncertainty propagation methods, both non-intrusive and intrusive, are described. Finally, pros and cons of the different approaches and their use in the scientific community are presented. This leads us to identify future directions for research and methodological development of uncertainty modeling in biomedical engineering.

  18. Bioethanol-gasoline fuel blends: exhaust emissions and morphological characterization of particulate from a moped engine.

    Science.gov (United States)

    Seggiani, Maurizia; Prati, M Vittoria; Costagliola, M Antonietta; Puccini, Monica; Vitolo, Sandra

    2012-08-01

    This study was aimed at evaluating the effects of gasoline-ethanol blends on the exhaust emissions in a catalyst-equipped four-stroke moped engine. The ethanol was blended with unleaded gasoline in at percentages (10, 15, and 20% v/v). The regulated pollutants and the particulate matter emissions were evaluated over the European ECE R47 driving cycle on the chassis dynamometer bench. Particulate matter was characterized in terms of total mass collected on filters and total number ofparticles in the range 7 nm-10 microm measured by electrical low-pressure impactor (ELPI). In addition, particle-phase polycyclic aromatic hydrocarbons (PAHs) emissions were evaluated to assess the health impact of the emitted particulate. Finally, an accurate morphological analysis was performed on the particulate by high-resolution transmission electron microscope (TEM) equipped with a digital image-processing/data-acquisition system. In general, CO emission reductions of 60-70% were obtained with 15 and 20% v/v ethanol blends, while the ethanol use did not reduce hydrocarbon (HC) and NOx emissions. No evident effect of ethanol on the particulate mass emissions and associated PAHs emissions was observed. Twenty-one PAHs were quantified in the particulate phase with emissions ranging from 26 to 35 microg/km and benzo[a]pyrene equivalent (BaPeq) emission factors from 2.2 to 4.1 microg/km. Both particulate matter and associated PAHs with higher carcinogenic risk were mainly emitted in the submicrometer size range (<0.1 microm). On the basis of the TEM observations, no relevant effect of the ethanol use on the particulate morphology was evidenced, showing aggregates composed ofprimary particles with mean diameters in the range 17.5-32.5 nm.

  19. Analytical characterization of engineered ZnO nanoparticles relevant for hazard assessment

    Energy Technology Data Exchange (ETDEWEB)

    Bragaru, Adina, E-mail: adina.bragaru@imt.ro; Kusko, Mihaela [National Institute for Research and Development in Microtechnologies, Laboratory of Nanobiotechnology (Romania); Vasile, Eugeniu [SC METAV CD (Romania); Simion, Monica; Danila, Mihai; Ignat, Teodora; Mihalache, Iuliana; Pascu, Razvan; Craciunoiu, Florea [National Institute for Research and Development in Microtechnologies, Laboratory of Nanobiotechnology (Romania)

    2013-01-15

    The optoelectronic properties of zinc oxide nanoparticles (ZnO-NPs) have determined development of novel applications in catalysis, paints, wave filters, UV detectors, transparent conductive films, solar cells, or sunscreens. While the immediate advantages of using nano-ZnO in glass panel coatings and filter screens for lamps, as protecting products against bleaching, have been demonstrated, the potential environmental effect of the engineered NPs and the associated products was not fully estimated; this issue being of utmost importance, as these materials will be supplied to the market in quantities of tons per year, equating to thousands of square meters. In this study, ZnO-NPs with commercial name Zincox Trade-Mark-Sign have been subjected to a comprehensive characterization, relevant for hazard assessment, using complementary physico-chemical methods. Therefore, the morphological investigations have been corroborated with XRD pattern analyses and UV-Vis absorption related properties resulting an excellent correlation between the geometrical sizes revealed by microscopy (8.0-9.0 nm), and, respectively, the crystallite size (8.2-9.5 nm) and optical size (7.8 nm) calculated from the last two techniques' data. Furthermore, the hydrodynamic diameter of ZnO-NPs and stability of aqueous dispersions with different concentration of nanoparticles have been analyzed as function of significant solution parameters, like concentration, pH and solution ionic strength. The results suggest that solution chemistry exerts a strong influence on ZnO dissolution stability, the complete set of analyses providing useful information toward better control of dosage during biotoxicological tests.

  20. Development and characterization of novel electrically conductive PANI-PGS composites for cardiac tissue engineering applications.

    Science.gov (United States)

    Qazi, Taimoor H; Rai, Ranjana; Dippold, Dirk; Roether, Judith E; Schubert, Dirk W; Rosellini, Elisabetta; Barbani, Niccoletta; Boccaccini, Aldo R

    2014-06-01

    Cardiovascular diseases, especially myocardial infarction, are the leading cause of morbidity and mortality in the world, also resulting in huge economic burdens on national economies. A cardiac patch strategy aims at regenerating an infarcted heart by providing healthy functional cells to the injured region via a carrier substrate, and providing mechanical support, thereby preventing deleterious ventricular remodeling. In the present work, polyaniline (PANI) was doped with camphorsulfonic acid and blended with poly(glycerol-sebacate) at ratios of 10, 20 and 30vol.% PANI content to produce electrically conductive composite cardiac patches via the solvent casting method. The composites were characterized in terms of their electrical, mechanical and physicochemical properties. The in vitro biodegradability of the composites was also evaluated. Electrical conductivity increased from 0Scm(-1) for pure PGS to 0.018Scm(-1) for 30vol.% PANI-PGS samples. Moreover, the conductivities were preserved for at least 100h post fabrication. Tensile tests revealed an improvement in the elastic modulus, tensile strength and elasticity with increasing PANI content. The degradation products caused a local drop in pH, which was higher in all composite samples compared with pure PGS, hinting at a buffering effect due to the presence of PANI. Finally, the cytocompatibility of the composites was confirmed when C2C12 cells attached and proliferated on samples with varying PANI content. Furthermore, leaching of acid dopants from the developed composites did not have any deleterious effect on the viability of C2C12 cells. Taken together, these results confirm the potential of PANI-PGS composites for use as substrates to modulate cellular behavior via electrical stimulation, and as biocompatible scaffolds for cardiac tissue engineering applications. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Engineering characterization of ground motion. Task I. Effects of characteristics of free-field motion on structural response

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, R.P.; Short, S.A.; Merz, K.L.; Tokarz, F.J.; Idriss, I.M.; Power, M.S.; Sadigh, K.

    1984-05-01

    This report presents the results of the first task of a two-task study on the engineering characterization of earthquake ground motion for nuclear power plant design. The overall objective of this study is to develop recommendations for methods for selecting design response spectra or acceleration time histories to be used to characterize motion at the foundation level of nuclear power plants. Task I of the study develops a basis for selecting design response spectra, taking into account the characteristics of free-field ground motion found to be significant in causing structural damage.

  2. Engineered Hybrid Scaffolds of Poly(vinyl alcohol/Bioactive Glass for Potential Bone Engineering Applications: Synthesis, Characterization, Cytocompatibility, and Degradation

    Directory of Open Access Journals (Sweden)

    Hermes S. Costa

    2012-01-01

    Full Text Available The synthesis, characterization, preliminary cytocompatibility, and degradation behavior of the hybrids based on 70% Poly(vinyl alcohol and 30% bioactive glass (58SiO2–33CaO–9P2O5, BaG with macroporous tridimensional structure is reported for the first time. The effect of glutaraldehyde covalent crosslinker in the organic-inorganic nanostructures produced and, as a consequence, tailoring the hybrids properties was investigated. The PVA/BaG hybrids scaffolds are characterized by Fourier transform infrared spectroscopy (FTIR, scanning electron microscopy (SEM, X-ray diffraction (XRD, and X-ray Microcomputed tomography analysis (μCT. Cytotoxicity assessment is performed by the MTT method with VERO cell culture. Additionally, the hybrid in vitro degradation assay is conducted by measuring the mass loss by soaking in deionized water at 37°C for up to 21 days. The results have clearly shown that it is possible to modify the PVA/BaG hybrids properties and degradation behavior by engineering the structure using different concentrations of the chemical crosslinker. Moreover, these hybrid crosslinked nanostructures have presented 3D hierarchical pore size architecture varying within 10–450 μm and a suitable cytocompatibility for potential use in bone tissue engineering applications.

  3. The possibilities for measurement and characterization of diesel engine fine particles: A review

    Directory of Open Access Journals (Sweden)

    Petrović Velimir S.

    2011-01-01

    Full Text Available This review paper considers possible instrumentation for diesel engine fine particles exhaust emission evaluation. The modern diesel engines have extremely low particles emission almost at the level of measurement error of existing gravimetric measurement method. Since coarse particles are eliminated by new engine technologies, fine particles, with very negative effects on human health, dominate in the emission of current diesel engine. Therefore, it is necessary not only to measure mass of emitted particles but also to investigate other important particle characteristics as: particles number, particle size, particle number and mass distribution, particle active surface, particle composition etc. Therefore, existing measurement technologies used in aerosol science can be used also to study diesel engine particles properties. This most common instrumentation in aerosol technique is shortly reviewed in the paper with special attention on candidate instruments included in EU program on portable emissions measurement systems (PEMS.

  4. Characterization of Fasciola spp. in Myanmar on the basis of spermatogenesis status and nuclear and mitochondrial DNA markers.

    Science.gov (United States)

    Ichikawa, Madoka; Bawn, Saw; Maw, Ni Ni; Htun, Lat Lat; Thein, Myint; Gyi, Aung; Sunn, Kyaw; Katakura, Ken; Itagaki, Tadashi

    2011-12-01

    Fasciola spp. in Myanmar were characterized on the basis of spermatogenesis status and DNA markers of nuclear internal transcribed spacer 1 (ITS1) and mitochondrial NADH dehydrogenase subunit 1 (nad1). We collected 88 adult flukes from Yangon, Lashio, and Myitkyina. Spermatogenesis status was analyzed by the presence of sperm in the seminal vesicles, and 8 aspermic and 80 spermic flukes were detected. The flukes were identified on the basis of spermatogenesis status and ITS1 types which were analyzed by a PCR-RFLP method, and 80 spermic flukes were identified as F. gigantica. A very low detection rate of aspermic Fasciola sp. indicated that they are not established in Myanmar. In phylogenetic analyses, the 7 aspermic Fasciola sp. from Myitkyina displayed a haplotype in nad1 sequence, which was identical to that of aspermic Fasciola sp. from other Asian countries including China. Therefore, they were probably introduced from China through an infected domestic ruminant. On the other hand, 17 nad1 haplotypes detected in F. gigantica belonged to 2 clades unique to Myanmar, each with a distinct founder haplotype in a network analysis. This indicated a unique history of F. gigantica introduction into Myanmar involving ancient artificial movements of domestic ruminants.

  5. Characterizing demographics, injury severity, and intubation status for patients transported by air or ground ambulance to a rural burn center.

    Science.gov (United States)

    Ahmed, Azeemuddin; Van Heukelom, Paul; Harland, Karisa; Denning, Gerene; Liao, Junlin; Born, Janelle; Latenser, Barbara

    2014-01-01

    Our study was designed to characterize intubation status among patients transported by air or ground ambulance to a rural burn center. A retrospective chart review of patients arriving at our burn center from January 1, 2005 to December 31, 2009 was completed. Descriptive and multivariate analyses were performed. During the study period, 259 air and 590 ground ambulance patients met inclusion criteria. Air ambulance patients were older and had higher total body surface area burned, lower Glasgow Coma scores, longer lengths of stay, and more frequent inhalation injuries. Approximately 10% of patients arriving by air were intubated after burn center admission, and 49% of intubated patients were extubated within 24 hours of admission. These values were 2% and 40%, respectively, for patients transported by ground. Increasing age and air ambulance transport increased the overall likelihood of change in intubation status. The likelihood of intubation by burn center providers increased with age, with suspicion of inhalation injury, and for patients transported by air. The likelihood of extubation within 24 hours of burn center admission increased with age, decreased with suspected inhalation injury, and was independent of transport mode. Among our patient population, more severely injured patients were being transported by air ambulance. However, age, suspicion of inhalation injury, and mode of transport showed a complex pattern of associations with changes in intubation status, and illustrate the need to develop better prehospital guidelines for intubation in burn patients.

  6. Seismic Hazard Characterization at the DOE Savannah River Site (SRS): Status report

    Energy Technology Data Exchange (ETDEWEB)

    Savy, J.B.

    1994-06-24

    The purpose of the Seismic Hazard Characterization project for the Savannah River Site (SRS-SHC) is to develop estimates of the seismic hazard for several locations within the SRS. Given the differences in the geology and geotechnical characteristics at each location, the estimates of the seismic hazard are to allow for the specific local conditions at each site. Characterization of seismic hazard is a critical factor for the design of new facilities as well as for the review and potential retrofit of existing facilities at SRS. The scope of the SRS seismic hazard characterization reported in this document is limited to the Probabilistic Seismic Hazard Analysis (PSHA). The goal of the project is to provide seismic hazard estimates based on a state-of-the-art method which is consistent with developments and findings of several ongoing studies which are deemed to bring improvements in the state of the seismic hazard analyses.

  7. The Current Status of Germplum Database: a Tool for Characterization of Plum Genetic Resources in Romania

    Directory of Open Access Journals (Sweden)

    Monica Harta

    2016-11-01

    Full Text Available In Romania, Prunus genetic resources are kept in collections of varieties, populations and biotypes, mainly located in research and development institutes or fruit growing stations and, in the last years, by some private enterprises. Creating the experimental model for the Germplum database based on phenotypic descriptors and SSR molecular markers analysis is an important and topical objective for the efficient characterization of genetic resources and also for establishing a public-private partnership for the effective management of plum germplasm resources in Romania. The technical development of the Germplum database was completed and data will be added continuously after characterizing each new accession.

  8. Functional expression and characterization of plant ABC transporters in Xenopus laevis oocytes for transport engineering purposes

    DEFF Research Database (Denmark)

    Xu, Deyang; Veres, Dorottya; Belew, Zeinu Mussa

    2016-01-01

    Transport engineering in bioengineering is aimed at efficient export of the final product to reduce toxicity and feedback inhibition and to increase yield. The ATP-binding cassette (ABC) transporters with their highly diverse substrate specificity and role in cellular efflux are potentially suita...... provided will hopefully contribute to more successful transport engineering in synthetic biology.......Transport engineering in bioengineering is aimed at efficient export of the final product to reduce toxicity and feedback inhibition and to increase yield. The ATP-binding cassette (ABC) transporters with their highly diverse substrate specificity and role in cellular efflux are potentially...... suitable in transport engineering approaches, although their size and high number of introns make them notoriously difficult to clone. Here, we report a novel in planta “exon engineering” strategy for cloning of full-length coding sequence of ABC transporters followed by methods for biochemical...

  9. Radiological, physical, and chemical characterization of low-level alpha contaminated wastes stored at the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Apel, M.L.; Becker, G.K.; Ragan, Z.K.; Frasure, J.; Raivo, B.D.; Gale, L.G.; Pace, D.P.

    1994-03-01

    This document provides radiological, physical, and chemical characterization data for low-level alpha-contaminated radioactive and low-level alpha-contaminated radioactive and hazardous (i.e., mixed) wastes stored at the Idaho National Engineering Laboratory and considered for treatment under the Private Sector Participation Initiative Program. Waste characterization data are provided in the form of INEL Waste Profile Sheets. These documents provide, for each content code, information on waste identification, waste description, waste storage configuration, physical/chemical waste composition, radionuclide and associated alpha activity waste characterization data, and hazardous constituents present in the waste. Information is provided for 97 waste streams which represent an estimated total volume of 25,450 m 3 corresponding to a total mass of approximately 12,000,000 kg. In addition, considerable information concerning alpha, beta, gamma, and neutron source term data specific to Rocky Flats-generated waste forms stored at the INEL are provided to assist in facility design specification.

  10. Engineering ceramics

    CERN Document Server

    Bengisu, Murat

    2001-01-01

    This is a comprehensive book applying especially to junior and senior engineering students pursuing Materials Science/ Engineering, Ceramic Engineering and Mechanical Engineering degrees. It is also a reference book for other disciplines such as Chemical Engineering, Biomedical Engineering, Nuclear Engineering and Environmental Engineering. Important properties of most engineering ceramics are given in detailed tables. Many current and possible applications of engineering ceramics are described, which can be used as a guide for materials selection and for potential future research. While covering all relevant information regarding raw materials, processing properties, characterization and applications of engineering ceramics, the book also summarizes most recent innovations and developments in this field as a result of extensive literature search.

  11. Characterization of Material Response During Arc-Jet Testing with Optical Methods Status and Perspectives

    Science.gov (United States)

    Winter, Michael

    2012-01-01

    The characterization of ablation and recession of heat shield materials during arc jet testing is an important step towards understanding the governing processes during these tests and therefore for a successful extrapolation of ground test data to flight. The behavior of ablative heat shield materials in a ground-based arc jet facility is usually monitored through measurement of temperature distributions (across the surface and in-depth), and through measurement of the final surface recession. These measurements are then used to calibrate/validate materials thermal response codes, which have mathematical models with reasonably good fidelity to the physics and chemistry of ablation, and codes thus calibrated are used for predicting material behavior in flight environments. However, these thermal measurements only indirectly characterize the pyrolysis processes within an ablative material pyrolysis is the main effect during ablation. Quantification of pyrolysis chemistry would therefore provide more definitive and useful data for validation of the material response codes. Information of the chemical products of ablation, to various levels of detail, can be obtained using optical methods. Suitable optical methods to measure the shape and composition of these layers (with emphasis on the blowing layer) during arc jet testing are: 1) optical emission spectroscopy (OES) 2) filtered imaging 3) laser induced fluorescence (LIF) and 4) absorption spectroscopy. Several attempts have been made to optically measure the material response of ablative materials during arc-jet testing. Most recently, NH and OH have been identified in the boundary layer of a PICA ablator. These species are suitable candidates for a detection through PLIF which would enable a spatially-resolved characterization of the blowing layer in terms of both its shape and composition. The recent emission spectroscopy data will be presented and future experiments for a qualitative and quantitative

  12. Characterization of tissue-engineered posterior corneas using second- and third-harmonic generation microscopy.

    Directory of Open Access Journals (Sweden)

    Louis Jay

    Full Text Available Three-dimensional tissues, such as the cornea, are now being engineered as substitutes for the rehabilitation of vision in patients with blinding corneal diseases. Engineering of tissues for translational purposes requires a non-invasive monitoring to control the quality of the resulting biomaterial. Unfortunately, most current methods still imply invasive steps, such as fixation and staining, to clearly observe the tissue-engineered cornea, a transparent tissue with weak natural contrast. Second- and third-harmonic generation imaging are well known to provide high-contrast, high spatial resolution images of such tissues, by taking advantage of the endogenous contrast agents of the tissue itself. In this article, we imaged tissue-engineered corneal substitutes using both harmonic microscopy and classic histopathology techniques. We demonstrate that second- and third-harmonic imaging can non-invasively provide important information regarding the quality and the integrity of these partial-thickness posterior corneal substitutes (observation of collagen network, fibroblasts and endothelial cells. These two nonlinear imaging modalities offer the new opportunity of monitoring the engineered corneas during the entire process of production.

  13. Characterization of tissue-engineered posterior corneas using second- and third-harmonic generation microscopy.

    Science.gov (United States)

    Jay, Louis; Bourget, Jean-Michel; Goyer, Benjamin; Singh, Kanwarpal; Brunette, Isabelle; Ozaki, Tsuneyuki; Proulx, Stéphanie

    2015-01-01

    Three-dimensional tissues, such as the cornea, are now being engineered as substitutes for the rehabilitation of vision in patients with blinding corneal diseases. Engineering of tissues for translational purposes requires a non-invasive monitoring to control the quality of the resulting biomaterial. Unfortunately, most current methods still imply invasive steps, such as fixation and staining, to clearly observe the tissue-engineered cornea, a transparent tissue with weak natural contrast. Second- and third-harmonic generation imaging are well known to provide high-contrast, high spatial resolution images of such tissues, by taking advantage of the endogenous contrast agents of the tissue itself. In this article, we imaged tissue-engineered corneal substitutes using both harmonic microscopy and classic histopathology techniques. We demonstrate that second- and third-harmonic imaging can non-invasively provide important information regarding the quality and the integrity of these partial-thickness posterior corneal substitutes (observation of collagen network, fibroblasts and endothelial cells). These two nonlinear imaging modalities offer the new opportunity of monitoring the engineered corneas during the entire process of production.

  14. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Hao-Yang [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States); Salick, Max R. [Department of Engineering Physics, University of Wisconsin–Madison, WI (United States); Jing, Xin [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States); Jacques, Brianna R. [Department of Biology, University of Wisconsin–River Falls, WI (United States); Crone, Wendy C. [Department of Engineering Physics, University of Wisconsin–Madison, WI (United States); Peng, Xiang-Fang, E-mail: pmxfpeng@scut.edu.cn [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Turng, Lih-Sheng, E-mail: turng@engr.wisc.edu [Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States)

    2013-12-01

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. - Highlights: • Microcellular injection molding was used to fabricate tissue engineering scaffolds. • TPU/PLA tissue engineering scaffolds with tunable properties were fabricated. • Multiple test methods were used to characterize the scaffolds. • The biocompatibility of the scaffolds was confirmed by fibroblast cell culture. • Scaffolds produced have the potential to be used in multiple tissue applications.

  15. CHARACTERIZATION OF BENTONITE FOR ENGINEERED BARRIER SYSTEMS IN RADIOACTIVE WASTE DISPOSAL SITES

    Directory of Open Access Journals (Sweden)

    Dubravko Domitrović

    2012-07-01

    Full Text Available Engineered barrier systems are used in radioactive waste disposal sites in order to provide better protection of humans and the environment from the potential hazards associated with the radioactive waste disposal. The engineered barrier systems usually contain cement or clay (bentonite because of their isolation properties and long term performance. Quality control tests of clays are the same for all engineering barrier systems. Differences may arise in the required criteria to be met due for different application. Prescribed clay properties depend also on the type of host rocks. This article presents radioactive waste management based on best international practice. Standard quality control procedures for bentonite used as a sealing barrier in radioactive waste disposal sites are described as some personal experiences and results of the index tests (free swelling index, water adsorption capacity, plasticity limits and hydraulic permeability of bentonite (the paper is published in Croatian.

  16. Characterization of the current status of ichthyofauna in the Techa river

    Energy Technology Data Exchange (ETDEWEB)

    Pryakhin, E.; Tryapitsina, G.; Akleyev, A. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation); Rudolfsen, G. [Norwegian Radiation Protection Authority - NRPA, and University of Tromsoe (Norway); Teien, H.C. [Norwegian University of Life Sciences - UMB, Center of Excellence in Environmental Radioactivity - CERAD (Norway)

    2014-07-01

    Within the period from 1949 to 1956 industrial non-technological low-level radioactive wastes of Mayak PA were released into the Techa River and associated wetland (Chelyabinsk Oblast, Russia). Over the whole period 76 millions m{sup 3} of effluents were discharged with total activity of about 1.1*10{sup 17} Bq. Ichthyofauna is one of the groups of hydrobionts which are most sensitive to the impact of a wide range of adverse environmental factors, including radioactive contamination of the water ecosystems. In the years 2011 - 2013 the research into the status of the ichthyofauna of the Techa River due to long term exposure to radionuclides was conducted. Sampling and fish catching were performed twice a year (in may during spawning and in august during feeding) at three sampling stations with different levels of radioactive contamination: in the upper reaches (RT1), in the middle reaches (RT2), and in the low reaches (RT3) of the river. At each station, samples of water, bottom sediments, zooplankton, zoo-benthos, algae, and fish (roach, perch, and pike) were collected. {sup 137}Cs, {sup 90}Sr and {sup 3}H were determined in all samples. The following parameters were measured in each fish specimen: weight and size of the body, age, sex, fin color, sperm motility during spawning, and morphometric parameters. Hematologic, cytogenetic, cytologic investigations of the studied fish specimen were also conducted. In spring, samples of sperm were taken from male fish at stations RT1 and in a River Mias (RM) as a control for the determination of sperm mobility. The content of {sup 137}Cs, {sup 90}Sr and {sup 3}H in water of the Techa River at different sampling stations (2012) is given in the Table 1. ERICA Assessment Tool was used for the calculation of absorbed dose rate in a body of fish with in approximation of the equilibrium distribution of radionuclides in an organism and in the surrounding medium (Table 2). The following biological effects, which could be

  17. Septic Encephalopathy Characterized by Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion and Early Nonconvulsive Status Epilepticus

    Directory of Open Access Journals (Sweden)

    Hiroshi Yamaguchi

    2016-01-01

    Full Text Available Infection, whether viral or bacterial, can result in various forms of brain dysfunction (encephalopathy. Septic encephalopathy (SE is caused by an excessive immune reaction to infection, with clinical features including disturbed consciousness and seizures. Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD is usually accompanied by viral infection in children and is characterized by biphasic seizures and impaired consciousness. The initial neurologic symptom of AESD is typically a febrile seizure that frequently lasts longer than 30 minutes. However, the possible forms this seizure takes are unclear. For example, it is unknown if nonconvulsive status epilepticus (NCSE could be an early seizure symptomatic of AESD. In addition, thus far no cases of combined SE and AESD have been reported. Here, we describe the first reported case of SE with AESD that notably demonstrated NCSE as an early seizure.

  18. Characterization of the Water Quality Status on a Stretch of River Lérez around a Small Hydroelectric Power Station

    Directory of Open Access Journals (Sweden)

    Enrique Valero

    2012-10-01

    Full Text Available The renewable energy emerged as a solution to the environmental problems caused by the conventional sources of energy. Small hydropower (SHP is claimed to cause negligible effects on the ecosystem, although some environmental values are threatened and maintenance of an adequate water quality should be ensured. This work provides a characterization of the water quality status in a river stretch around a SHP plant on river Lérez, northwest Spain, for four years after its construction. The ecological and chemical status of the water as well as the ecological quality of the riparian habitat, were used as measures of quality. Data were compared with the water quality requirements. The variations in the quality parameters were analyzed over time and over the river sections with respect to the SHP plant elements. Two years after construction, the temperature and dissolved oxygen values achieved conditions for salmonid water and close to the reference condition, while pH values were low. The Iberian Biological Monitoring Working Party (IBMWP index showed a positive trend from two years after the construction and stabilized at “unpolluted or not considerably altered water”. Quality parameters did not present significant differences between sampling points. The SHP plant construction momentarily altered the quality characteristics of the water.

  19. Fabrication and Characterization of Spongy Denuded Amniotic Membrane Based Scaffold for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Ehsan Taghiabadi

    2015-01-01

    Full Text Available Objective: As a biological tissue material, amniotic membrane (AM has low immunogenicity and to date has been widely adopted in clinical practice. However, some features such as low biomechanical consistency and rapid biodegradation is limited the application of AM. Therefore, in this study, we fabricated a novel three-dimensional (3D spongy scaffold made of the extracellular matrix (ECM of denuded AM. Due to their unique characteristics which are similar to the skin, these scaffolds can be considered as an alternative option in skin tissue engineering. Materials and Methods: In this experimental study, cellular components of human amniotic membrane (HAM were removed with 0.03% (w/v sodium dodecyl sulphate (SDS. Quantitative analysis was performed to determine levels of Glycosaminoglycans (GAGs, collagen, and deoxyribonucleic acid (DNA. To increase the low efficiency and purity of the ECM component, especially collagen and GAG, we applied an acid solubilization procedure hydrochloridric acid (HCl 0.1 M with pepsin (1 mg/ml. In the present experiment 1-ethyl-3-(3-dimethyl aminopropyl carbodiimide hydrochloride (EDC/N-hydroxysuccinimide (NHS cross linker agent was used to improve the mechanical properties of 3D lyophilized AM scaffold. The spongy 3D AM scaffolds were specified, by scanning electron microscopy, hematoxylin and eosin (H&E staining, a swelling test, and mechanical strength and in vitro biodegradation tests. Human fetal fibroblast culture systems were used to establish that the scafolds were cytocompatible. Results: Histological analysis of treated human AM showed impressive removal of cellular components. DNA content was diminished after treatment (39 ± 4.06 μg/ml vs. 341 ± 29.60 μg/ml. Differences were observed between cellular and denude AM in matrix collagen (478 ± 18.06 μg/mg vs. 361 ± 27.47 μg/mg.With the optimum concentration of 1 mM NHS/EDC ratio1:4, chemical cross-linker agent could significantly increase the

  20. Characterization of the Methylation Status of and Myogenic Regulator Factors in Cell Myogenic Differentiation

    Directory of Open Access Journals (Sweden)

    Zhe Chao

    2016-07-01

    Full Text Available Epigenetic processes in the development of skeletal muscle have been appreciated for over a decade. DNA methylation is a major epigenetic modification important for regulating gene expression and suppressing spurious transcription. Up to now, the importance of epigenetic marks in the regulation of Pax7 and myogenic regulatory factors (MRFs expression is far less explored. In the present study, semi-quantitative the real-time polymerase chain reaction (RT-PCR analyses showed MyoD and Myf5 were expressed in activated and quiescent C2C12 cells. MyoG was expressed in a later stage of myogenesis. Pax7 was weakly expressed in differentiated C2C12 cells. To further understand the regulation of expression of these genes, the DNA methylation status of Pax7, MyoD, and Myf5 was determined by bisulfite sequencing PCR. During the C2C12 myoblasts fusion process, the changes of promoter and exon 1 methylation of Pax7, MyoD, and Myf5 genes were observed. In addition, an inverse relationship of low methylation and high expression was found. These results suggest that DNA methylation may be an important mechanism regulating Pax7 and MRFs transcription in cell myogenic differentiation.

  1. Bulk Combinatorial Synthesis and High Throughput Characterization for Rapid Assessment of Magnetic Materials: Application of Laser Engineered Net Shaping (LENS™)

    Science.gov (United States)

    Geng, J.; Nlebedim, I. C.; Besser, M. F.; Simsek, E.; Ott, R. T.

    2016-07-01

    A bulk combinatorial approach for synthesizing alloy libraries using laser engineered net shaping (LENS™; i.e., 3D printing) was utilized to rapidly assess material systems for magnetic applications. The LENS™ system feeds powders in different ratios into a melt pool created by a laser to synthesize samples with bulk (millimeters) dimensions. By analyzing these libraries with autosampler differential scanning calorimeter/thermal gravimetric analysis and vibrating sample magnetometry, we are able to rapidly characterize the thermodynamic and magnetic properties of the libraries. The Fe-Co binary alloy was used as a model system and the results were compared with data in the literature.

  2. Engineering industrial oil biosynthesis: cloning and characterization of Kennedy pathway acyltransferases from novel oilseed species

    Science.gov (United States)

    For more than twenty years, various industrial, governmental, and academic laboratories have developed and refined genetic engineering strategies aimed at manipulating lipid metabolism in plants and microbes. The goal of these projects is to produce renewable specialized oils that can effectively c...

  3. Minimal analytical characterization of engineered nanomaterials needed for hazard assessment in biological matrices

    NARCIS (Netherlands)

    Bouwmeester, H.; Lynch, I.; Marvin, H.J.P.; Dawson, K.A.; Berges, M.; Braguer, D.; Byrne, H.J.; Casey, A.; Chambers, G.; Clift, M.J.D.; Elia, G.; Fernandes, T.F.; fjellsbo, L.B.; Hatto, P.; Juillerat, L.; Klein, C.; Kreyling, W.G.; Nickel, C.; Riediker, M.; Stone, V.

    2011-01-01

    This paper presents the outcomes from a workshop of the European Network on the Health and Environmental Impact of Nanomaterials (NanoImpactNet). During the workshop, 45 experts in the field of safety assessment of engineered nanomaterials addressed the need to systematically study sets of

  4. Characterizing Twitter Communication--A Case Study of International Engineering Academic Units

    Science.gov (United States)

    Palmer, Stuart

    2014-01-01

    Engineering academic units might engage with social media for a range of purposes including for general communication with students, staff, alumni, other important stakeholders and the wider community at large; for student recruitment and for marketing and promotion more generally. This paper presents an investigation into the use of Twitter by…

  5. Development and characterization of poly(ε-caprolactone) hollow fiber membranes for vascular tissue engineering

    NARCIS (Netherlands)

    Diban-Ibrahim Gomez, Nazely; Haimi, Suvi; Bolhuis-Versteeg, Lydia A.M.; Da Silva Teixeira, Sandra; Miettinen, S.; Poot, Andreas A.; Grijpma, Dirk W.; Stamatialis, Dimitrios

    2013-01-01

    The fabrication of tissue-engineered scaffolds for small-caliber blood vessels still remains a challenge. In the present work, we prepared poly(ε-caprolactone) (PCL) hollow fiber (HF) membranes, suitable for small-diameter blood vessel regeneration, by a phase separation spinning technique. The diff

  6. Chemistry Characterization of Jet Aircraft Engine Particulate by XPS: Results from APEX III

    Science.gov (United States)

    Vander Wal, Randy L.; Bryg, Victoria M.

    2014-01-01

    This paper reports XPS analysis of jet exhaust particulate from a B737, Lear, ERJ, and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and platforms. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20 percent or more. By lower resolution survey scans various elements including transition metals are identified along with lighter elements such as S, N, and O in the form of oxides. Burning additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their presence can be used as a tracer for identifying soots from aircraft engines as well as diagnostic for monitoring engine performance and wear.

  7. Crosslinked type II collagen matrices: preparation, characterization, and potential for cartilage engineering.

    NARCIS (Netherlands)

    Pieper, J.S.; Kraan, P.M. van der; Hafmans, T.G.M.; Kamp, J.; Buma, P.; Susante, J.L.C. van; Berg, W.B. van den; Veerkamp, J.H.; Kuppevelt, A.H.M.S.M. van

    2002-01-01

    The limited intrinsic repair capacity of articular cartilage has stimulated continuing efforts to develop tissue engineered analogues. Matrices composed of type II collagen and chondroitin sulfate (CS), the major constituents of hyaline cartilage, may create an appropriate environment for the genera

  8. Characterizing Twitter Communication--A Case Study of International Engineering Academic Units

    Science.gov (United States)

    Palmer, Stuart

    2014-01-01

    Engineering academic units might engage with social media for a range of purposes including for general communication with students, staff, alumni, other important stakeholders and the wider community at large; for student recruitment and for marketing and promotion more generally. This paper presents an investigation into the use of Twitter by…

  9. Toxicological characterization of diesel engine emissions using biodiesel and a closed soot filter

    NARCIS (Netherlands)

    Kooter, Ingeborg M.; van Vugt, Marcel A. T. M.; Jedynska, Aleksandra D.; Tromp, Peter C.; Houtzager, Marc M. G.; Verbeek, Ruud P.; Kadijk, Gerrit; Mulderij, Mariska; Krul, Cyrille A. M.

    2011-01-01

    This study was designed to determine the toxicity (oxidative stress, cytotoxicity, genotoxicity) in extracts of combustion aerosols. A typical Euro Ill heavy truck engine was tested over the European Transient Cycle with three different fuels: conventional diesel EN590, biodiesel EN14214 as 8100 and

  10. Chemistry characterization of jet aircraft engine particulate matter by XPS: Results from APEX III

    Science.gov (United States)

    Vander Wal, Randy L.; Bryg, Victoria M.; Huang, Chung-Hsuan

    2016-09-01

    This paper reports X-ray photoelectron spectroscopy (XPS) analysis of jet exhaust particulate matter (PM) from a B737, Lear, ERJ and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and powers. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20% or more. By survey scans various elements including transition metals are identified along with lighter elements such as S, N and O in the form of oxides. Additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their collective presence could serve as an environmental tracer for identifying PM originating from aircraft engines and serving as a diagnostic for engine performance and wear.

  11. Establishment and characterization of human engineered cells stably expressing large extracellular matrix proteins.

    Science.gov (United States)

    Kwon, Daekee; Kang, Gwang-Sik; Han, Dong Keun; Park, Kwideok; Kim, Jae-Hwan; Lee, Soo-Hong

    2014-01-01

    Commercially available extracellular matrix (ECM) hydrogel-coated culture plates have been used to study the relationship between the ECM microenvironment and stem cell behavior. However, it is unclear whether ECM-coated dishes mimic the natural ECM microenvironment because the architecture of the ECM is constructed of randomly distributed fibers. The purpose of this study was the production and confirmation of human engineered cell lines stably expressing large ECM proteins such as collagen I/II and fibronectin. First, large (over 10 kb) ECM vectors encoding human collagen I/II and fibronectin were constructed and the circular vectors were linearized. Second, the linear ECM vectors were introduced into immortalized human embryonic kidney cells using various transfection methods. The polyethylenimine and liposome methods showed higher efficiencies than electroporation for transfection of these large vectors. Third, human ECM engineered cells were established by stable integration of the vector into the genomic DNA and resulted in stable overexpression of mRNA and proteins. In summary, human engineered cell lines stably expressing large ECM proteins such as human collagen I/II and fibronectin were successfully prepared, and secretion of the ECM components into the surrounding environment was confirmed by immunocytochemistry. Thus, human ECM engineered cells naturally secreting ECM components could be valuable for studying the relationship between the native ECM microenvironment and stem cell behavior.

  12. Dynamic material characterization by combining ballistic testing and an engineering model

    NARCIS (Netherlands)

    Carton, E.P.; Roebroeks, G.H.J.J.; Wal, R. van der

    2013-01-01

    At TNO several energy-based engineering models have been created for various failure mechanism occurring in ballistic testing of materials, like ductile hole growth, denting, plugging, etc. Such models are also under development for ceramic and fiberbased materials (fabrics). As the models are

  13. Using Learning Analytics to Characterize Student Experimentation Strategies in Engineering Design

    Science.gov (United States)

    Vieira, Camilo; Goldstein, Molly Hathaway; Purzer, Senay; Magana, Alejandra J.

    2016-01-01

    Engineering design is a complex process both for students to participate in and for instructors to assess. Informed designers use the key strategy of conducting experiments as they test ideas to inform next steps. Conversely, beginning designers experiment less, often with confounding variables. These behaviours are not easy to assess in…

  14. Toxicological characterization of diesel engine emissions using biodiesel and a closed soot filter

    NARCIS (Netherlands)

    Kooter, I.M.; Vugt, M.A.T.M. van; Jedynska, A.D.; Tromp, P.C.; Houtzager, M.M.G.; Verbeek, R.P.; Kadijk, G.; Mulderij, M.; Krul, C.A.M.

    2011-01-01

    This study was designed to determine the toxicity (oxidative stress, cytotoxicity, genotoxicity) in extracts of combustion aerosols. A typical Euro III heavy truck engine was tested over the European Transient Cycle with three different fuels: conventional diesel EN590, biodiesel EN14214 as B100 and

  15. Toxicological characterization of diesel engine emissions using biodiesel and a closed soot filter

    NARCIS (Netherlands)

    Kooter, I.M.; Vugt, M.A.T.M. van; Jedynska, A.D.; Tromp, P.C.; Houtzager, M.M.G.; Verbeek, R.P.; Kadijk, G.; Mulderij, M.; Krul, C.A.M.

    2011-01-01

    This study was designed to determine the toxicity (oxidative stress, cytotoxicity, genotoxicity) in extracts of combustion aerosols. A typical Euro III heavy truck engine was tested over the European Transient Cycle with three different fuels: conventional diesel EN590, biodiesel EN14214 as B100 and

  16. Toxicological characterization of diesel engine emissions using biodiesel and a closed soot filter

    NARCIS (Netherlands)

    Kooter, Ingeborg M.; van Vugt, Marcel A. T. M.; Jedynska, Aleksandra D.; Tromp, Peter C.; Houtzager, Marc M. G.; Verbeek, Ruud P.; Kadijk, Gerrit; Mulderij, Mariska; Krul, Cyrille A. M.

    2011-01-01

    This study was designed to determine the toxicity (oxidative stress, cytotoxicity, genotoxicity) in extracts of combustion aerosols. A typical Euro Ill heavy truck engine was tested over the European Transient Cycle with three different fuels: conventional diesel EN590, biodiesel EN14214 as 8100 and

  17. 78 FR 51706 - Bayer CropScience LP; Determination of Nonregulated Status of Soybean Genetically Engineered for...

    Science.gov (United States)

    2013-08-21

    ... regulated article under our regulations governing the introduction of certain genetically engineered....aphis.usda.gov/biotechnology/not_reg.html under APHIS Petition Number 09-328-01p and are posted with the..., Biotechnology Environmental Analysis Branch, Environmental Risk Analysis Programs, Biotechnology Regulatory...

  18. Ampelographic Characterization and Sanitary Status of Grapevine Cultivar ‘Prč bijeli’ (Vitis vinifera L.

    Directory of Open Access Journals (Sweden)

    Goran Zdunić

    2008-06-01

    Full Text Available ‘Prč bijeli’ is an old Croatian autochthonous grapevine cultivar (Vitis vinifera L., which has not been ampelographically characterized in detail until now. Ampelographic description was performed following 52 morphological, 22 phyllometric and seven bunches dimension characteristics. ‘Prč bijeli’ showed acceptable yield and a must composition suitable for oenological purposes, with low acidity value and medium sugar content. The following synonyms were established: ‘Ćimavica’, ‘Parč’ and ‘Muškat’. The results of sanitary analysis (ELISA test on four viruses on twenty-seven vines revealed that 92.6 % samples were GLRaV-3 positive, while ArMV was not detected. Only one vine was free of the tested viruses.

  19. Characterization of neural stemness status through the neurogenesis process for bone marrow mesenchymal stem cells.

    Science.gov (United States)

    Mohammad, Maeda H; Al-Shammari, Ahmed M; Al-Juboory, Ahmad Adnan; Yaseen, Nahi Y

    2016-01-01

    The in vitro isolation, identification, differentiation, and neurogenesis characterization of the sources of mesenchymal stem cells (MSCs) were investigated to produce two types of cells in culture: neural cells and neural stem cells (NSCs). These types of stem cells were used as successful sources for the further treatment of central nervous system defects and injuries. The mouse bone marrow MSCs were used as the source of the stem cells in this study. β-Mercaptoethanol (BME) was used as the main inducer of the neurogenesis pathway to induce neural cells and to identify NSCs. Three types of neural markers were used: nestin as the immaturation stage marker, neurofilament light chain as the early neural marker, and microtubule-associated protein 2 as the maturation marker through different time intervals in the neurogenesis process starting from the MSCs, (as undifferentiated cells), NSCs, production stages, and toward neuron cells (as differentiated cells). The results of different exposure times to BME of the neural markers analysis done by immunocytochemistry and real time-polymerase chain reaction helped us to identify the exact timing for the neural stemness state. The results showed that the best exposure time that may be used for the production of NSCs was 6 hours. The best maintenance media for NSCs were also identified. Furthermore, we optimized exposure to BME with different times and concentrations, which could be an interesting way to modulate specific neuronal differentiation and obtain autologous neuronal phenotypes. This study was able to characterize NSCs in culture under differentiation for neurogenesis in the pathway of the neural differentiation process by studying the expressed neural genes and the ability to maintain these NSCs in culture for further differentiation in thousands of functional neurons for the treatment of brain and spinal cord injuries and defects.

  20. Mechanical Characterization of Tissue-Engineered Cartilage Using Microscopic Magnetic Resonance Elastography

    Science.gov (United States)

    Yin, Ziying; Schmid, Thomas M.; Yasar, Temel K.; Liu, Yifei; Royston, Thomas J.

    2014-01-01

    Knowledge of mechanical properties of tissue-engineered cartilage is essential for the optimization of cartilage tissue engineering strategies. Microscopic magnetic resonance elastography (μMRE) is a recently developed MR-based technique that can nondestructively visualize shear wave motion. From the observed wave pattern in MR phase images the tissue mechanical properties (e.g., shear modulus or stiffness) can be extracted. For quantification of the dynamic shear properties of small and stiff tissue-engineered cartilage, μMRE needs to be performed at frequencies in the kilohertz range. However, at frequencies greater than 1 kHz shear waves are rapidly attenuated in soft tissues. In this study μMRE, with geometric focusing, was used to overcome the rapid wave attenuation at high frequencies, enabling the measurement of the shear modulus of tissue-engineered cartilage. This methodology was first tested at a frequency of 5 kHz using a model system composed of alginate beads embedded in agarose, and then applied to evaluate extracellular matrix development in a chondrocyte pellet over a 3-week culture period. The shear stiffness in the pellet was found to increase over time (from 6.4 to 16.4 kPa), and the increase was correlated with both the proteoglycan content and the collagen content of the chondrocyte pellets (R2=0.776 and 0.724, respectively). Our study demonstrates that μMRE when performed with geometric focusing can be used to calculate and map the shear properties within tissue-engineered cartilage during its development. PMID:24266395

  1. Electrical engineering design using characterized elements; Conception en genie electrique a l'aide d'elements caracterises

    Energy Technology Data Exchange (ETDEWEB)

    Demni, H.E.

    2004-10-15

    This work treats systematic design of energy transformation structures used in Electrical Engineering. We propose an approach dedicated to design by association of characterized elements. Starting from a set of specifications, the designer has to define a coherent structure by assembling predefined elements. Within this framework, we adopt a characterization approach that takes into account various criteria necessary for design. Then, this approach allowed us to develop methodologies for designing electric energy transformation structures. These methodologies were used to implement a software application based on three tools: a data base as an elements library, a graphic tool allowing the construction of energy transformation structures, an expert module which helps the designer in his work. (author)

  2. Current Status and Characterization of CANDU Spent Fuel for Geological Disposal System Design

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Dong Keun; Lee, Seung Woo; Cha, Jeong Hun; Choi, Jong Won; Choi, Heui Joo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Yang [SK Engineering and Construction, Seoul (Korea, Republic of)

    2008-06-15

    Inventories to be disposed of, reference turn up, and source terms for CANDU spent fuel were evaluated for geological disposal system design. The historical and projected inventory by 2040 is expected to be 14,600 MtU under the condition of 30-year lifetime for unit 1 and 40-year lifetime for other units in Wolsong site. As a result of statistical analysis for discharge burnup of the spent fuels generated by 2007, average and stand deviation revealed 6,987 MWD/MtU and 1,167, respectively. From this result, the reference burnup was determined as 8,100 MWD/MtU which covers 84% of spent fuels in total. Source terms such as nuclide concentration for a long-term safety analysis, decay heat, thermo-mechanical analysis, and radiation intensity and spectrum was characterized by using ORIGEN-ARP containing conservativeness in the aspect of decay heat up to several thousand years. The results from this study will be useful for the design of storage and disposal facilities.

  3. Optimization of keratin/alginate scaffold using RSM and its characterization for tissue engineering.

    Science.gov (United States)

    Gupta, Pratima; Nayak, Kush Kumar

    2016-04-01

    The scaffold for tissue engineering was fabricated from a binary blend of keratin/alginate. The concentration and ratio of keratin and alginate was optimized by response surface methodology in a scaffold. The structural compatibility between keratin and alginate was examined by X-ray diffractometer and Fourier transforms infrared spectroscopy. Apparent porosity of the scaffold was calculated by Archimedes principles and its observed value of was found 96.25 ± 0.04%. The pore size of the scaffold was observed in the range between 10 and 200 μm. Tensile strength (0.33 ± 0.26 MPa) and percent of elongation at break (23.33 ± 2.52%) are the reported mechanical strength of the scaffold. Positive antimicrobial activity and in vitro degradation further confirms the fabrication of a scaffold required for tissue engineering application.

  4. Mechanical characterization and non-linear elastic modeling of poly(glycerol sebacate) for soft tissue engineering.

    Science.gov (United States)

    Mitsak, Anna G; Dunn, Andrew M; Hollister, Scott J

    2012-07-01

    Scaffold tissue engineering strategies for repairing and replacing soft tissue aim to improve reconstructive and corrective surgical techniques whose limitations include suboptimal mechanical properties, fibrous capsule formation and volume loss due to graft resorption. An effective tissue engineering strategy requires a scaffolding material with low elastic modulus that behaves similarly to soft tissue, which has been characterized as a nonlinear elastic material. The material must also have the ability to be manufactured into specifically designed architectures. Poly(glycerol sebacate) (PGS) is a thermoset elastomer that meets these criteria. We hypothesize that the mechanical properties of PGS can be modulated through curing condition and architecture to produce materials with a range of stiffnesses. To evaluate this hypothesis, we manufactured PGS constructs cured under various conditions and having one of two architectures (solid or porous). Specimens were then tensile tested according to ASTM standards and the data were modeled using a nonlinear elastic Neo-Hookean model. Architecture and testing conditions, including elongation rate and wet versus dry conditions, affected the mechanical properties. Increasing curing time and temperature led to increased tangent modulus and decreased maximum strain for solid constructs. Porous constructs had lower nonlinear elastic properties, as did constructs of both architectures tested under simulated physiological conditions (wetted at 37 °C). Both solid and porous PGS specimens could be modeled well with the Neo-Hookean model. Future studies include comparing PGS properties to other biological tissue types and designing and characterizing PGS scaffolds for regenerating these tissues.

  5. The design, fabrication and characterization of fluidic membranes for micro-engines with the aim of frequency lowering

    Science.gov (United States)

    Chutani, R.; Formosa, F.; de Labachelerie, M.; Badel, A.; Lanzetta, F.

    2016-12-01

    This paper describes the design, microfabrication and linear dynamic characterization of low frequency thick membranes as a potential technological solution for resonant micro-engines, for which classical pistons cannot be used. The proposed structure is called a hybrid fluid-membrane and consists of two thin flexible membranes that encapsulate an incompressible fluid. Lower frequency structures, compared to geometrically equivalent single layer membranes, are thus obtained. Each flexible membrane is based on a composite structure which comprises a silicon planar logarithmic spiral spring embedded in a room temperature vulcanization silicone polymer. Thus, the stiffness and sealing features are dissociated for a better design control. The developed realization and assembly process is demonstrated at the wafer level. The process involves the anodic bonding of multiple stacks of silicon/glass structures, fluid filling and sealing. Various dimensions of hybrid fluid-membranes are successfully fabricated. Their dynamic characterization underlines the agreement between experimental and theoretical results. The results provide the opportunity for the design and fabrication of low frequency membranes to match the dynamics requirements of micro-engines.

  6. Characterization of Pulse Detonation Engine Performance with Varying Free Stream Stagnation Pressure Levels

    Science.gov (United States)

    2006-03-01

    compressible 38 flow equations. The Quad 4 cylinder head is a standard cylinder head with a dual overhead camshaft . As when installed in an...automobile engine each camshaft independently opens and closes a set of 8 purge and 8 fill valves. The camshaft lobes are each geometrically designed for...given lift and duration. The lift of a camshaft lobe refers to the overall distance the valve will be moved off the seat at maximum lift. The

  7. Functional characterization of detergent-decellularized equine tendon extracellular matrix for tissue engineering applications.

    Directory of Open Access Journals (Sweden)

    Daniel W Youngstrom

    Full Text Available Natural extracellular matrix provides a number of distinct advantages for engineering replacement orthopedic tissue due to its intrinsic functional properties. The goal of this study was to optimize a biologically derived scaffold for tendon tissue engineering using equine flexor digitorum superficialis tendons. We investigated changes in scaffold composition and ultrastructure in response to several mechanical, detergent and enzymatic decellularization protocols using microscopic techniques and a panel of biochemical assays to evaluate total protein, collagen, glycosaminoglycan, and deoxyribonucleic acid content. Biocompatibility was also assessed with static mesenchymal stem cell (MSC culture. Implementation of a combination of freeze/thaw cycles, incubation in 2% sodium dodecyl sulfate (SDS, trypsinization, treatment with DNase-I, and ethanol sterilization produced a non-cytotoxic biomaterial free of appreciable residual cellular debris with no significant modification of biomechanical properties. These decellularized tendon scaffolds (DTS are suitable for complex tissue engineering applications, as they provide a clean slate for cell culture while maintaining native three-dimensional architecture.

  8. Fabrication and mechanical characterization of 3D electrospun scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Wright, L D; Young, R T; Andric, T; Freeman, J W, E-mail: jwfreeman@vt.ed [Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

    2010-10-01

    Electrospinning is a polymer processing technique that produces fibrous structures comparable to the extracellular matrix of many tissues. Electrospinning, however, has been severely limited in its tissue engineering capabilities because this technique has produced few three-dimensional structures. Sintering of electrospun materials provides a method to fabricate unique architectures and allow much larger structures to be made. Electrospun mats were sintered into strips and cylinders, and their tensile and compressive mechanical properties were measured. In addition, electrospun materials with salt pores (salt embedded within the material and then leached out) were fabricated to improve porosity of the electrospun materials for tissue engineering scaffolds. Sintered electrospun poly(d,l-lactide) and poly(l-lactide) (PDLA/PLLA) materials have higher tensile mechanical properties (modulus: 72.3 MPa, yield: 960 kPa) compared to unsintered PLLA (modulus: 40.36 MPa, yield: 675.5 kPa). Electrospun PDLA/PLLA cylinders with and without salt-leached pores had compressive moduli of 6.69 and 26.86 MPa, respectively, and compressive yields of 1.36 and 0.56 MPa, respectively. Sintering of electrospun materials is a novel technique that improves electrospinning application in tissue engineering by increasing the size and types of electrospun structures that can be fabricated.

  9. Characterization and Effect of Using Mahua Oil Biodiesel as Fuel in Compression Ignition Engine

    Institute of Scientific and Technical Information of China (English)

    N.Kapilan; T.P.Ashok Babu; R.P.Reddy

    2009-01-01

    There is an increasing interest in India, to search for suitable alternative fuels that are environment friendly. This led to the choice of Mahua Oil (MO) as one of the main alternative fuels to diesel. In this investigation, Mahua Oil Biodiesel (MOB) and its blend with diesel were used as fuel in a single cylinder, direct injection and com-pression ignition engine. The MOB was prepared from MO by transesterification using methanol and potassium hydroxide. The fuel properties of MOB are close to the diesel and confirm to the ASTM standards. From the en-gine test analysis, it was observed that the MOB, B5 and B20 blend results in lower CO, HC and smoke emis-sions as compared to diesel. But the B5 and B20 blends results in higher efficiency as compared to MOB. Hence MOB or blends of MOB and diesel 035 or B20) can be used as a substitute for diesel in diesel engines used in transportation as well as in the agriculture sector.

  10. Status Report on the Microbial Characterization of Halite and Groundwater Samples from the WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Swanson, Juliet S. [Los Alamos National Laboratory; Reed, Donald T. [Los Alamos National Laboratory; Ams, David A. [Los Alamos National Laboratory; Norden, Diana [Ohio State University; Simmons, Karen A. [Los Alamos National Laboratory

    2012-07-10

    This report summarizes the progress made in the ongoing task of characterizing the microbial community structures within the WIPP repository and in surrounding groundwaters. Through cultivation and DNA-based identification, the potential activity of these organisms is being inferred, thus leading to a better understanding of their impact on WIPP performance. Members of the three biological domains - Bacteria, Archaea, and Eukarya (in this case, Fungi) - that are associated with WIPP halite have been identified. Thus far, their activity has been limited to aerobic respiration; anaerobic incubations are underway. WIPP halite constitutes the near-field microbial environment. We expect that microbial activity in this setting will proceed from aerobic respiration, through nitrate reduction to focus on sulfate reduction. This is also the current WIPP performance assessment (PA) position. Sulfate reduction can occur at extremely high ionic strengths, and sulfate is available in WIPP brines and in the anhydrite interbeds. The role of methanogenesis in the WIPP remains unclear, due to both energetic constraints imposed by a high-salt environment and substrate selectivity, and it is no longer considered in PA. Archaea identified in WIPP halite thus far fall exclusively within the family Halobacteriaceae. These include Halobacterium noricense, cultivated from both low- and high-salt media, and a Halorubrum-like species. The former has also been detected in other salt mines worldwide; the latter likely constitutes a new species. Little is known of its function, but it was prevalent in experiments investigating the biodegradation of organic complexing agents in WIPP brines. Bacterial signatures associated with WIPP halite include members of the phylum Proteobacteria - Halomonas, Pelomonas, Limnobacter, and Chromohalobacter - but only the latter has been isolated. Also detected and cultivated were Salinicoccus and Nesterenkonia spp. Fungi were also isolated from halite. Although

  11. Estimation of Membrane Hydration Status for Standby Proton Exchange Membrane Fuel Cell Systems by Impedance Measurement: First Results on Variable Temperature Stack Characterization

    DEFF Research Database (Denmark)

    Bidoggia, Benoit; Kær, Søren Knudsen

    2013-01-01

    Fuel cells are getting growing interest in both backup systems and electric vehicles. Although these systems are characterized by periods of standby, they must be able to start at any instant in the shortest possible time. However, the membranes of which proton exchange membrane fuel cells are made...... way for estimating the hydration status and the temperature of its membrane before the system is started up. A summarizing table with the complete characterization of the fuel cell stack is included in this article....

  12. Combined heart rate variability and dynamic measures for quantitatively characterizing the cardiac stress status during cycling exercise.

    Science.gov (United States)

    Chen, Szi-Wen; Liaw, Jiunn-Woei; Chang, Ya-Ju; Chuang, Li-Ling; Chien, Chun-Tse

    2015-08-01

    In this study, we aimed to seek for different ways of measuring cardiac stress in terms of heart rate variability (HRV) and heart rate (HR) dynamics, and to develop a novel index that can effectively summarize the information reflected by these measures to continuously and quantitatively characterize the cardiac stress status during physical exercise. Standard deviation, spectral measure of HRV as well as a nonlinear detrended fluctuation analysis (DFA) based fractal-like behavior measure of HR dynamics were all evaluated on the RR time series derived from windowed electrocardiogram (ECG) data for the subjects undergoing cycling exercise. We recruited eleven young healthy subjects in our tests. Each subject was asked to maintain a fixed speed under a constant load during the pedaling test. We obtained the running estimates of the standard deviation of the normal-to-normal interval (SDNN), the high-fidelity power spectral density (PSD) of HRV, and the DFA scaling exponent α, respectively. A trend analysis and a multivariate linear regression analysis of these measures were then performed. Numerical experimental results produced by our analyses showed that a decrease in both SDNN and α was seen during the cycling exercise, while there was no significant correlation between the standard lower frequency to higher frequency (LF-to-HF) spectral power ratio of HRV and the exercise intensity. In addition, while the SDNN and α were both negatively correlated with the Borg rating of perceived exertion (RPE) scale value, it seemed that the LF-to-HF power ratio might not have substantial impact on the Borg value, suggesting that the SDNN and α may be further used as features to detect the cardiac stress status during the physical exercise. We further approached this detection problem by applying a linear discriminant analysis (LDA) to both feature candidates for the task of cardiac stress stratification. As a result, a time-varying parameter, referred to as the cardiac

  13. Construction and characterization of VL-VH tail-parallel genetically engineered antibodies against staphylococcal enterotoxins.

    Science.gov (United States)

    He, Xianzhi; Zhang, Lei; Liu, Pengchong; Liu, Li; Deng, Hui; Huang, Jinhai

    2015-03-01

    Staphylococcal enterotoxins (SEs) produced by Staphylococcus aureus have increasingly given rise to human health and food safety. Genetically engineered small molecular antibody is a useful tool in immuno-detection and treatment for clinical illness caused by SEs. In this study, we constructed the V(L)-V(H) tail-parallel genetically engineered antibody against SEs by using the repertoire of rearranged germ-line immunoglobulin variable region genes. Total RNA were extracted from six hybridoma cell lines that stably express anti-SEs antibodies. The variable region genes of light chain (V(L)) and heavy chain (V(H)) were cloned by reverse transcription PCR, and their classical murine antibody structure and functional V(D)J gene rearrangement were analyzed. To construct the eukaryotic V(H)-V(L) tail-parallel co-expression vectors based on the "5'-V(H)-ivs-IRES-V(L)-3'" mode, the ivs-IRES fragment and V(L) genes were spliced by two-step overlap extension PCR, and then, the recombined gene fragment and V(H) genes were inserted into the pcDNA3.1(+) expression vector sequentially. And then the constructed eukaryotic expression clones termed as p2C2HILO and p5C12HILO were transfected into baby hamster kidney 21 cell line, respectively. Two clonal cell lines stably expressing V(L)-V(H) tail-parallel antibodies against SEs were obtained, and the antibodies that expressed intracytoplasma were evaluated by enzyme-linked immunosorbent assay, immunofluorescence assay, and flow cytometry. SEs can stimulate the expression of some chemokines and chemokine receptors in porcine IPEC-J2 cells; mRNA transcription level of four chemokines and chemokine receptors can be blocked by the recombinant SE antibody prepared in this study. Our results showed that it is possible to get functional V(L)-V(H) tail-parallel genetically engineered antibodies in same vector using eukaryotic expression system.

  14. Characterizing Observed Limit Cycles in the Cassini Main Engine Guidance Control System

    Science.gov (United States)

    Rizvi, Farheen; Weitl, Raquel M.

    2011-01-01

    The Cassini spacecraft dynamics-related telemetry during long Main Engine (ME) burns has indicated the presence of stable limit cycles between 0.03-0.04 Hz frequencies. These stable limit cycles cause the spacecraft to possess non-zero oscillating rates for extended periods of time. This indicates that the linear ME guidance control system does not model the complete dynamics of the spacecraft. In this study, we propose that the observed limit cycles in the spacecraft dynamics telemetry appear from a stable interaction between the unmodeled nonlinear elements in the ME guidance control system. Many nonlinearities in the control system emerge from translating the linear engine gimbal actuator (EGA) motion into a spacecraft rotation. One such nonlinearity comes from the gear backlash in the EGA system, which is the focus of this paper. The limit cycle characteristics and behavior can be predicted by modeling this gear backlash nonlinear element via a describing function and studying the interaction of this describing function with the overall dynamics of the spacecraft. The linear ME guidance controller and gear backlash nonlinearity are modeled analytically. The frequency, magnitude, and nature of the limit cycle are obtained from the frequency response of the ME guidance controller and nonlinear element. In addition, the ME guidance controller along with the nonlinearity is simulated. The simulation response contains a limit cycle with similar characterstics as predicted analytically: 0.03-0.04 Hz frequency and stable, sustained oscillations. The analytical and simulated limit cycle responses are compared to the flight telemetry for long burns such as the Saturn Orbit Insertion and Main Engine Orbit Trim Maneuvers. The analytical and simulated limit cycle characteristics compare well with the actual observed limit cycles in the flight telemetry. Both have frequencies between 0.03-0.04 Hz and stable oscillations. This work shows that the stable limit cycles occur

  15. Characterizing human pluripotent-stem-cell-derived vascular cells for tissue engineering applications.

    Science.gov (United States)

    Kusuma, Sravanti; Facklam, Amanda; Gerecht, Sharon

    2015-02-15

    Tissue-engineered constructs are rendered useless without a functional vasculature owing to a lack of nutrients and oxygen. Cell-based approaches to reconstruct blood vessels can yield structures that mimic native vasculature and aid transplantation. Vascular derivatives of human induced pluripotent stem cells (hiPSCs) offer opportunities to generate patient-specific therapies and potentially provide unlimited amounts of vascular cells. To be used in engineered vascular constructs and confer therapeutic benefit, vascular derivatives must exhibit additional key properties, including extracellular matrix (ECM) production to confer structural integrity and growth factor production to facilitate integration. In this study, we examine the hypothesis that vascular cells derived from hiPSCs exhibit these critical properties to facilitate their use in engineered tissues. hiPSCs were codifferentiated toward early vascular cells (EVCs), a bicellular population of endothelial cells (ECs) and pericytes, under varying low-oxygen differentiation conditions; subsequently, ECs were isolated and passaged. We found that EVCs differentiated under low-oxygen conditions produced copious amounts of collagen IV and fibronectin as well as vascular endothelial growth factor and angiopoietin 2. EVCs differentiated under atmospheric conditions did not demonstrate such abundant ECM expression, but exhibited greater expression of angiopoietin 1. Isolated ECs could proliferate up to three passages while maintaining the EC marker vascular endothelial cadherin. Isolated ECs demonstrated an increased propensity to produce ECM compared with their EVC correlates and took on an arterial-like fate. These findings illustrate that hiPSC vascular derivates hold great potential for therapeutic use and should continue to be a preferred cell source for vascular construction.

  16. Fuel and engine characterization study of catalytically cracked waste transformer oil

    KAUST Repository

    Prasanna Raj Yadav, S.

    2015-05-01

    This research work targets on the effective utilization of WTO (waste transformer oil) in a diesel engine and thereby, reducing the environmental problems caused by its disposal into open land. The novelty of the work lies in adoption of catalytic cracking process to chemically treat WTO, wherein waste fly ash has been considered as a catalyst for the first time. Interestingly, both the oil and catalyst used are waste products, enabling reduction in total fuel cost and providing additional benefit of effective waste management. With the considerable token that use of activated fly ash as catalyst requires lower reaction temperature, catalytic cracking was performed only in the range of 350-400°C. As a result of this fuel treatment process, the thermal and physical properties of CCWTO (catalytically cracked waste transformer oil), as determined by ASTM standard methods, were found to be agreeable for its use in a diesel engine. Further, FTIR analysis of CCWTO discerned the presence of essential hydrocarbons such as carbon and hydrogen. From the experimental investigation of CCWTO - diesel blends in a diesel engine, performance and combustion characteristics were shown to be improved, with a notable increase in BTE (brake thermal efficiency) and PHRR (peak heat release rate) for CCWTO 50 by 7.4% and 13.2%, respectively, than that of diesel at full load condition. In the same note, emissions such as smoke, HC (hydrocarbon) and CO (carbon monoxide) were noted to be reduced at the expense of increased NOx (nitrogen oxides) emission. © 2015 Elsevier Ltd. All rights reserved.

  17. Preparation and characterization of LPPS NiCoCrAlYTa coatings for gas turbine engine

    Institute of Scientific and Technical Information of China (English)

    洪瑞江; 周克崧; 王德政; 朱晖朝; 邝子奇

    2001-01-01

    NiCoCrAlYTa coatings have been deposited onto an aircraft gas turbine engine blade using a LPPS unit equipped with a computerized robot. Optimal processing conditions, including spray parameters, the trajectory of the robot, and the synchronized movements between the torch and the blade, have been developed for superior coating properties. Transferred-arc treatment, providing a preheating and a cleaning of the substrate surface, enhances the adherence of the coatings to the substrate. The resulting LPPS coatings show dense and uniform characteristics with ideal hardness, and good corrosion resistance to cycle oxidation.

  18. Characterizing the time-perspective of nations with search engine query data.

    Science.gov (United States)

    Noguchi, Takao; Stewart, Neil; Olivola, Christopher Y; Moat, Helen Susannah; Preis, Tobias

    2014-01-01

    Vast quantities of data on human behavior are being created by our everyday internet usage. Building upon a recent study by Preis, Moat, Stanley, and Bishop (2012), we used search engine query data to construct measures of the time-perspective of nations, and tested these measures against per-capita gross domestic product (GDP). The results indicate that nations with higher per-capita GDP are more focused on the future and less on the past, and that when these nations do focus on the past, it is more likely to be the distant past. These results demonstrate the viability of using nation-level data to build psychological constructs.

  19. Characterization of aluminium-based water treatment residual for potential phosphorus removal in engineered wetlands

    OpenAIRE

    Babatunde, A.O.; Zhao, Y.Q.; Burke, A. M.; Morris, M. A.; HANRAHAN, J.P.

    2009-01-01

    Aluminium-based water treatment residual (Al-WTR) is the most widely generated residual from water treatment facilities worldwide. It is regarded as a by-product of no reuse potential and landfilled. This study assessed Al-WTR as a potential phosphate-removing substrate in engineered wetlands for wastewater treatment. Results indicate the specific surface area ranged from 28.0 m2 g-1 to 41.4 m2 g-1 and this increased with increasing particle size. X-ray Diffraction (XRD), Fourier transform in...

  20. Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program FY-98 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, Alan Keith; Mc Cray, John Alan; Rogers, Adam Zachary; Simmons, R. F.; Palethorpe, S. J.

    1999-03-01

    The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to near-surface disposal. During fiscal year 1998, three grout formulations were studied for low-activity wastes derived from INTEC liquid sodium-bearing waste. Compressive strength and leach results are presented for phosphate bonding cement, acidic grout, and alkaline grout formulations. In an additional study, grout formulations are recommended for stabilization of the INTEC underground storage tank residual heels.

  1. Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program, FY-98 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, A.K.; Rogers, A.Z.; McCray, J.A.; Simmons, R.F.; Palethorpe, S.J.

    1999-03-01

    The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to near-surface disposal. During fiscal year 1998, three grout formulations were studied for low-activity wastes derived from INTEC liquid sodium-bearing waste. Compressive strength and leach results are presented for phosphate bonding cement, acidic grout, and alkaline grout formulations. In an additional study, grout formulations are recommended for stabilization of the INTEC underground storage tank residual heels.

  2. Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program FY-99 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, Alan Keith; Mc Cray, John Alan; Kirkham, Robert John; Pao, Jenn Hai; Hinckley, Steve Harold

    1999-10-01

    The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to near-surface disposal. During fiscal year 1999, grout formulations were studied for transuranic waste derived from INTEC liquid sodium-bearing waste and for projected newly generated low-level liquid waste. Additional studies were completed on radionuclide leaching, microbial degradation, waste neutralization, and a small mockup for grouting the INTEC underground storage tank residual heels.

  3. Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program FY-99 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    A. K. Herbst; J. A. McCray; R. J. Kirkham; J. Pao; S. H. Hinckley

    1999-09-30

    The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to near-surface disposal. During fiscal year 1999, grout formulations were studied for transuranic waste derived from INTEC liquid sodium-bearing waste and for projected newly generated low-level liquid waste. Additional studies were completed on radionuclide leaching, microbial degradation, waste neutralization, and a small mockup for grouting the INTEC underground storage tank residual heels.

  4. Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program FY-2000 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, Alan Keith; Mc Cray, John Alan; Kirkham, Robert John; Pao, Jenn Hai; Argyle, Mark Don; Lauerhass, Lance; Bendixsen, Carl Lee; Hinckley, Steve Harold

    2000-11-01

    The Low-Activity Waste Process Technology Program anticipated that grouting will be used for disposal of low-level and transuranic wastes generated at the Idaho Nuclear Technology Engineering Center (INTEC). During fiscal year 2000, grout formulations were studied for transuranic waste derived from INTEC liquid sodium-bearing waste and for projected newly generated low-level liquid waste. Additional studies were completed using silica gel and other absorbents to solidify sodium-bearing wastes. A feasibility study and conceptual design were completed for the construction of a grout pilot plant for simulated wastes and demonstration facility for actual wastes.

  5. Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program FY-2000 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, A.K.; McCray, J.A.; Kirkham, R.J.; Pao, J.; Argyle, M.D.; Lauerhass, L.; Bendixsen, C.L.; Hinckley, S.H.

    2000-10-31

    The Low-Activity Waste Process Technology Program anticipated that grouting will be used for disposal of low-level and transuranic wastes generated at the Idaho Nuclear Technology Engineering Center (INTEC). During fiscal year 2000, grout formulations were studied for transuranic waste derived from INTEC liquid sodium-bearing waste and for projected newly generated low-level liquid waste. Additional studies were completed using silica gel and other absorbents to solidify sodium-bearing wastes. A feasibility study and conceptual design were completed for the construction of a grout pilot plant for simulated wastes and demonstration facility for actual wastes.

  6. Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program, FY-98 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, A.K.; Rogers, A.Z.; McCray, J.A.; Simmons, R.F.; Palethorpe, S.J.

    1999-03-01

    The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to near-surface disposal. During fiscal year 1998, three grout formulations were studied for low-activity wastes derived from INTEC liquid sodium-bearing waste. Compressive strength and leach results are presented for phosphate bonding cement, acidic grout, and alkaline grout formulations. In an additional study, grout formulations are recommended for stabilization of the INTEC underground storage tank residual heels.

  7. Idaho Nuclear Technology and Engineering Center Low-Activity Waste Process Technology Program FY-98 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, A.K.; McCray, J.A.; Rogers, A.Z.; Simmons, R.F.; Palethrope, S.J.

    1999-03-01

    The Low-Activity Waste Process Technology Program at the Idaho Nuclear Technology and Engineering Center (INTEC) anticipates that large volumes of low-level/low-activity wastes will need to be grouted prior to near-surface disposal. During fiscal year 1998, three grout formulations were studied for low-activity wastes derived from INTEC liquid sodium-bearing waste. Compressive strength and leach results are presented for phosphate bonding cement, acidic grout, and alkaline grout formulations. In an additional study, grout formulations are recommended for stabilization of the INTEC underground storage tank residual heels.

  8. Idaho Nuclear Technology and Engineering Center Sodium-Bearing Waste Treatment Research and Development FY-2002 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, Alan Keith; Deldebbio, John Anthony; Mc Cray, John Alan; Kirkham, Robert John; Olson, Lonnie Gene; Scholes, Bradley Adams

    2002-09-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) is considering several optional processes for disposal of liquid sodium-bearing waste. During fiscal year 2002, immobilization-related research included of grout formulation development for sodium-bearing waste, absorption of the waste on silica gel, and off-gas system mercury collection and breakthrough using activated carbon. Experimental results indicate that sodium-bearing waste can be immobilized in grout at 70 weight percent and onto silica gel at 74 weight percent. Furthermore, a loading of 11 weight percent mercury in sulfur-impregnated activated carbon was achieved with 99.8% off-gas mercury removal efficiency.

  9. Linker engineering for fusion protein construction: Improvement and characterization of a GLP-1 fusion protein.

    Science.gov (United States)

    Kong, Yuelin; Tong, Yue; Gao, Mingming; Chen, Chen; Gao, Xiangdong; Yao, Wenbing

    2016-01-01

    Protein engineering has been successfully applied in protein drug discovery. Using this technology, we previously have constructed a fusion protein by linking the globular domain of adiponectin to the C-terminus of a glucagon-like peptide-1 (GLP-1) analog. Herein, to further improve its bioactivity, we reconstructed this fusion protein by introducing linker peptides of different length and flexibility. The reconstructed fusion proteins were overexpressed in Escherichia coli and purified using nickel affinity chromatography. Their agonist activity towards receptors of GLP-1 and adiponectin were assessed in vitro by using luciferase assay and AMP-activated protein kinase (AMPK) immunoblotting, respectively. The effects of the selected fusion protein on glucose and lipid metabolism were evaluated in mice. The fusion protein reconstructed using a linker peptide of AMGPSSGAPGGGGS showed high potency in activating GLP-1 receptor and triggering AMPK phosphorylation via activating the adiponectin receptor. Remarkably, the optimized fusion protein was highly effective in lowering blood glucose and lipids in mice. Collectively, these findings demonstrate that the bioactivity of this GLP-1 fusion protein can be significantly promoted by linker engineering, and indicate that the optimized GLP-1 fusion protein is a promising lead structure for anti-diabetic drug discovery.

  10. Design, fabrication and characterization of oxidized alginate-gelatin hydrogels for muscle tissue engineering applications.

    Science.gov (United States)

    Baniasadi, Hossein; Mashayekhan, Shohreh; Fadaoddini, Samira; Haghirsharifzamini, Yasamin

    2016-07-01

    In this study, we reported the preparation of self cross-linked oxidized alginate-gelatin hydrogels for muscle tissue engineering. The effect of oxidation degree (OD) and oxidized alginate/gelatin (OA/GEL) weight ratio were examined and the results showed that in the constant OA/GEL weight ratio, both cross-linking density and Young's modulus enhanced by increasing OD due to increment of aldehyde groups. Furthermore, the degradation rate was increased with increasing OD probably due to decrement in alginate molecular weight during oxidation reaction facilitated degradation of alginate chains. MTT cytotoxicity assays performed on Wharton's Jelly-derived umbilical cord mesenchymal stem cells cultured on hydrogels with OD of 30% showed that the highest rate of cell proliferation belong to hydrogel with OA/GEL weight ratio of 30/70. Overall, it can be concluded from all obtained results that the prepared hydrogel with OA/GEL weight ratio and OD of 30/70 and 30%, respectively, could be proper candidate for use in muscle tissue engineering. © The Author(s) 2016.

  11. Synthesis and characterization of crosslinked gellan/PVA nanofibers for tissue engineering application.

    Science.gov (United States)

    Vashisth, Priya; Pruthi, Vikas

    2016-10-01

    Electrospun nanofibers based on gellan are considered as promising biomaterial for tissue engineering and wound healing applications. However, major hurdles in usage of these nanofibers are their poor stability and deprived structural consistency in aqueous medium which is a prerequisite for their application in the biomedical sector. In this investigation, three dimensional nanofibers, consisting of gellan and PVA have been fabricated and then stabilized under various crosslinking conditions in order to improve their physiochemical stability. The impacts of different crosslinking procedures on the gellan/PVA nanofibers were examined in terms of changes in morphological, mechanical, swelling and biological properties. Superior tensile strength and strain was recorded in case of crosslinked nanofibers as compared to non-crosslinked nanofibers. Contact angles and swelling properties of fabricated gellan/PVA nanofibers were found to vary with the crosslinking method. All crosslinking conditions were evaluated with regard to their response towards human dermal fibroblast (3T3L1) cells. Biocompatibility studies suggested that the fabricated crosslinked gellan/PVA nanofibers hold a great prospective in the biomedical engineering arena.

  12. Engineered antibody CH2 domains binding to nucleolin: Isolation, characterization and improvement of aggregation.

    Science.gov (United States)

    Li, De-Zhi; Gong, Rui; Zheng, Jun; Chen, Xi-Hai; Dimitrov, Dimiter S; Zhao, Qi

    2017-02-12

    Smaller recombinant antibody fragments are now emerging as alternatives of conventional antibodies. Especially, immunoglobulin (Ig) constant CH2 domain and engineered CH2 with improved stability are promising as scaffolds for selection of specific binders to various antigens. We constructed a yeast display library based on an engineered human IgG1 CH2 scaffold with diversified loop regions. A group of CH2 binders were isolated from this yeast display library by panning against nucleolin, which is a tumor-associated antigen involved in cell proliferation, tumor cell growth and angiogenesis. Out of 20 mutants, we selected 3 clones exhibiting relatively high affinities to nucleolin on yeasts. However, recombinant CH2 mutants aggregated when they were expressed. To find the mechanism of the aggregation, we employed computational prediction approaches through structural homology models of CH2 binders. The analysis of potential aggregation prone regions (APRs) and solvent accessible surface areas (ASAs) indicated two hydrophobic residues, Val264 and Leu309, in the β-sheet, in which replacement of both charged residues led to significantly decrease of the protein aggregation. The newly identified CH2 binders could be improved to use as candidate therapeutics or research reagents in the future.

  13. Fabrication and characterization of regenerated silk scaffolds reinforced with natural silk fibers for bone tissue engineering.

    Science.gov (United States)

    Mobini, Sahba; Hoyer, Birgit; Solati-Hashjin, Mehran; Lode, Anja; Nosoudi, Nasim; Samadikuchaksaraei, Ali; Gelinsky, Michael

    2013-08-01

    We introduce a novel Bombyx mori silk-based composite material developed for bone tissue engineering. Three-dimensional scaffolds were fabricated by embedding of natural degummed silk fibers in a matrix of regenerated fibroin, followed by freeze-drying. Different ratios of fibers to fibroin were investigated with respect to their influence on mechanical and biological properties. For all scaffold types, an interconnected porous structure suitable for cell penetration was proven by scanning electron microscopy. Compressive tests, carried out in static and cyclic mode under dry as well as wet conditions, revealed a strong impact of fiber reinforcement on compressive modulus and compressive stress. Cell culture experiments with human mesenchymal stem cells demonstrated that the fiber/fibroin composite scaffolds support cell attachment, proliferation, as well as differentiation along the osteoblastic lineage. Considering the excellent mechanical and biological properties, novel fiber/fibroin scaffolds appear to be an interesting structure for prospect studies in bone tissue engineering. Copyright © 2013 Wiley Periodicals, Inc.

  14. Cardiac tissue engineering: cell seeding, cultivation parameters, and tissue construct characterization.

    Science.gov (United States)

    Carrier, R L; Papadaki, M; Rupnick, M; Schoen, F J; Bursac, N; Langer, R; Freed, L E; Vunjak-Novakovic, G

    1999-09-01

    Cardiac tissue engineering has been motivated by the need to create functional tissue equivalents for scientific studies and cardiac tissue repair. We previously demonstrated that contractile cardiac cell-polymer constructs can be cultivated using isolated cells, 3-dimensional scaffolds, and bioreactors. In the present work, we examined the effects of (1) cell source (neonatal rat or embryonic chick), (2) initial cell seeding density, (3) cell seeding vessel, and (4) tissue culture vessel on the structure and composition of engineered cardiac muscle. Constructs seeded under well-mixed conditions with rat heart cells at a high initial density ((6-8) x 10(6) cells/polymer scaffold) maintained structural integrity and contained macroscopic contractile areas (approximately 20 mm(2)). Seeding in rotating vessels (laminar flow) rather than mixed flasks (turbulent flow) resulted in 23% higher seeding efficiency and 20% less cell damage as assessed by medium lactate dehydrogenase levels (p laminar and dynamic, yielded constructs with a more active, aerobic metabolism as compared to constructs cultured in mixed or static flasks. After 1-2 weeks of cultivation, tissue constructs expressed cardiac specific proteins and ultrastructural features and had approximately 2-6 times lower cellularity (p < 0.05) but similar metabolic activity per unit cell when compared to native cardiac tissue.

  15. Fabrication and characterization of biomimetic multichanneled crosslinked-urethane-doped polyester tissue engineered nerve guides.

    Science.gov (United States)

    Tran, Richard T; Choy, Wai Man; Cao, Hung; Qattan, Ibrahim; Chiao, Jung-Chih; Ip, Wing Yuk; Yeung, Kelvin Wai Kwok; Yang, Jian

    2014-08-01

    Biomimetic scaffolds that replicate the native architecture and mechanical properties of target tissues have been recently shown to be a very promising strategy to guide cellular growth and facilitate tissue regeneration. In this study, porous, soft, and elastic crosslinked urethane-doped polyester (CUPE) tissue engineered nerve guides were fabricated with multiple longitudinally oriented channels and an external non-porous sheath to mimic the native endoneurial microtubular and epineurium structure, respectively. The fabrication technique described herein is highly adaptable and allows for fine control over the resulting nerve guide architecture in terms of channel number, channel diameter, porosity, and mechanical properties. Biomimetic multichanneled CUPE guides were fabricated with various channel numbers and displayed an ultimate peak stress of 1.38 ± 0.22 MPa with a corresponding elongation at break of 122.76 ± 42.17%, which were comparable to that of native nerve tissue. The CUPE nerve guides were also evaluated in vivo for the repair of a 1 cm rat sciatic nerve defect. Although histological evaluations revealed collapse of the inner structure from CUPE TENGs, the CUPE nerve guides displayed fiber populations and densities comparable with nerve autograft controls after 8 weeks of implantation. These studies are the first report of a CUPE-based biomimetic multichanneled nerve guide and warrant future studies towards optimization of the channel geometry for use in neural tissue engineering.

  16. Crank angle resolved flow field characterization of a heavy-duty one-cylinder optical engine

    Energy Technology Data Exchange (ETDEWEB)

    Van der Meyden, T.J.

    2009-03-15

    Soot and nitric oxide (NOx) production are the main negative aspects of Diesel combustion. This is why new combustion strategies are being investigated, such as Premixed Charge Compression Ignition (PCCI). PCCI is one of the most promising combustion strategies for internal combustion engines in the future, since PCCI combustion is able to realize very low soot and nitric oxide emissions. PCCI combines the efficiency of a diesel and the low particulate emission of an Otto engine. To achieve PCCI combustion with limited heat release rates, the influence of charge stratification on combustion should be investigated. In this work, the first steps to achieve that goal are made. The first step is to determine in-cylinder velocities by measuring flow fields using Particle Image Velocimetry (PIV). The test setup consists of a one-cylinder optically accessible heavy duty engine driven by an electrical motor. The upper part of the liner and piston bottom are both made of sapphire. For PIV measurements a 10 Hz Nd:YAG Continuum Surelite laser is used with pulse energies of 140 mJ. The used camera is a Kodak Megaplus ES 1.0 CCD with 1008 x 1018 pixels. The seeding particles are produced from silicon oil using Laskin nozzles and have a diameter of about 0.7 im. Pre- and post- processing and the evaluation of the recorded PIV images is done using the commercially available software program PIVview (Pivtec). The velocity analysis is done using the commercial software program Tecplot. More knowledge is gathered on the in-cylinder velocities, aimed at a future detailed study on the effect of charge stratification in PCCI combustion. Ensemble averaged velocities, vorticities and strain rates, turbulence intensities and turbulent kinetic energies as a function of the crank angle, engine speed, measurement height and compression ratio have been investigated. Velocity and turbulence appear to be proportional to the engine speed. The position of the ensemble averaged swirl center as a

  17. Dielectric engineering: Characterization, development and process damage minimization of various silicon oxides

    NARCIS (Netherlands)

    Ackaert, Jan Germain Gabriel

    2004-01-01

    Over the various chapters, this thesis describes the characterization and development of a number of applications of silicon dioxides. An oxynitride is developed allowing a much higher SiGe epitaxial deposition rate in a bipolar process. Also a tunneloxide for non volatile memory application is

  18. Influence of overtime work, sleep duration, and perceived job characteristics on the physical and mental status of software engineers.

    Science.gov (United States)

    Nishikitani, Mariko; Nakao, Mutsuhiro; Karita, Kanae; Nomura, Kyoko; Yano, Eiji

    2005-10-01

    To investigate the impact of overtime work, sleep duration, and perceived job characteristics on physical and mental status, a cross-sectional study was conducted on 377 workers (average age; 28 years old) in an information-technology (IT) company, engaged in consultation, system integration solution, and data management relevant to IT system. The psychophysical outcomes of overtime work were assessed using the Hamilton Depression Scale (HDS), Profile of Mood Status (POMS), major physical symptoms, and overtime work data for the preceding three-months. Sleep duration was directly asked by a physician. A job strain index was defined as the ratio of job-demands to job-control scores evaluated using the Job Content Questionnaire (JCQ). In a univariate analysis, overtime work was significantly related with HDS scores, POMS anger-hostility scores, and the total physical symptom count in both sexes (all p job strain index. Sleep duration was negatively related to the symptom count in men and to POMS tension-anxiety scores in women (both p job strain index was positively related to POMS anger-hostility scores in both sexes and to HDS scores and POMS tension-anxiety scores in men (all p job strain index seemed to be better indicators for physical and mental distress in overloaded workers.

  19. Engineering soluble insect and plant cytochromes P450 for biochemical characterization

    DEFF Research Database (Denmark)

    Jensen, Mikael Kryger

    the cytochrome P450 (CYP) 79 and CYP405 family in plants and insects respectively, which convert the amino acid into its corresponding oxime through two sequential (N)-hydroxylation’s followed by a dehydration, decarboxylation and isomerization step. Enzymes from both families display a high degree of substrate...... specificity, unlike many mammalian cytochromes P450. CYP405A2 from Zygaena filipendulae and CYP79D3 from Lotus corniculatus both convert isoleucine and valine into their corresponding oximes, but neither will convert leucine neatly illustrating the high degree of specificity the enzymes possess. Previous work...... substrate specificity in the CYP79 and CYP405 families we chose to initiate a large-scale project, attempting to express and purify multiple P450s with the aim of obtaining crystal structures. The research presented in this thesis demonstrates how to engineer plant and insect microsomal cytochromes P450...

  20. Characterization of the Engineering Flow in a Miniaturised Bioreactor by Computational Fluid Dynamics

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hu; Parviz Ayazi Shamlou

    2004-01-01

    Three approaches based on computational fluid dynamics(CFD) techniques have been assessed for their ability to describe the engineering flow environment in a miniaturized mechanically agitated bioreactor. The three approaches tested were the source-sink(SS), the multiple reference frames(MRF) and the sliding grids (SG). In all the cases, the predictions of the velocity components agree with reported experimental data.However, the analysis of the results of the turbulent intensities predicted by the three approaches indicates the MRF and the SG techniques under predicted turbulent intensities are comparable to both experimental measurements and the SS method. The predicted power number and pumping number based on the SS approach are closer to typical reported experimental values compared to those obtained from the MRF and SG methods.

  1. Characterization of typical platelet injector flow configurations. [liquid propellant rocket engines

    Science.gov (United States)

    Hickox, C. E.

    1975-01-01

    A study to investigate the hydraulic atomization characteristics of several novel injector designs for use in liquid propellant rocket engines is presented. The injectors were manufactured from a series of thin stainless steel platelets through which orifices were very accurately formed by a photoetching process. These individual platelets were stacked together and the orifices aligned so as to produce flow passages of prescribed geometry. After alignment, the platelets were bonded into a single, 'platelet injector', unit by a diffusion bonding process. Because of the complex nature of the flow associated with platelet injectors, it was necessary to use experimental techniques, exclusively, throughout the study. Large scale models of the injectors were constructed from aluminum plates and the appropriate fluids were modeled using a glycerol-water solution. Stop-action photographs of test configurations, using spark-shadowgraph or stroboscopic back-lighting, are shown.

  2. Engineering and characterization of a packaged high-T c superconducting terahertz source module

    Science.gov (United States)

    Tsujimoto, Manabu; Doi, Takuji; Kuwano, Genki; Elarabi, Asem; Kakeya, Itsuhiro

    2017-06-01

    We present an effective engineering technique for compactly packaging high-T c superconducting continuous-wave terahertz source modules. A terahertz-emitting device, which consists of stacks of intrinsic Josephson junctions in single crystalline Bi2Sr2CaCu2O{}8+δ , bias electrodes, a collimating lens, and other components, is packaged into a single finger-sized assembly. The rigid and stable structure used for the packaging guarantees physical and chemical stability with good thermal contact, and provides reproducible characteristics with a high yield rate. The coherent terahertz waves can be emitted from the back side of the base crystal without significant screening. The intuitive results obtained from the numerical simulation are consistent with the observed thermal properties. The modules are easy to use, and thus intended for all users unfamiliar with superconducting electronic devices.

  3. Characterization of decellularized scaffold derived from porcine meniscus for tissue engineering applications

    Science.gov (United States)

    Gao, Shuang; Yuan, Zhiguo; Xi, Tingfei; Wei, Xiaojuan; Guo, Quanyi

    2016-06-01

    Menisci are fundamental fibrocartilaginous organs in knee joints. The injury in meniscus can impair normal knee function and predisposes patients to osteoarthritis. This study prepared decellularized meniscus scaffolds using a 1% (w/w) sodium dodecyl sulfate solution and sufficient rinsing steps. Complete cell removal was verified by hematoxylin and eosin staining and DNA content assay. Decellularized menisci had accordant tension properties to intact ones, but with declined compression properties. This occurred because the collagen fiber was not damaged but glycosaminoglycans was significantly lost during the decellularization process, which was confirmed by biochemical assay and histology staining. In vitro cytotoxicity assay demonstrated that decellularized meniscus scaffolds have no toxicity on L929 murine fibroblasts and porcine chondrocytes. Further experiment showed that porcine chondrocytes could adhere and proliferate on the scaffold surface, and some cells even could infiltrate into the scaffold. All results showed the potential of this decellularized meniscus to be the scaffolds in tissue engineering.

  4. Preparation and characterization of aloe vera blended collagen-chitosan composite scaffold for tissue engineering applications.

    Science.gov (United States)

    Jithendra, Panneerselvam; Rajam, Abraham Merlin; Kalaivani, Thambiran; Mandal, Asit Baran; Rose, Chellan

    2013-08-14

    Collagen-Chitosan (COL-CS) scaffolds supplemented with different concentrations (0.1-0.5%) of aloe vera (AV) were prepared and tested in vitro for their possible application in tissue engineering. After studying the microstructure and mechanical properties of all the composite preparations, a 0.2% AV blended COL-CS scaffold was chosen for further studies. Scaffolds were examined by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA) to understand the intermolecular interactions and their influence on the thermal property of the complex composite. Swelling property in phosphate buffered saline (pH 7.4) and in vitro biodegradability by collagenase digestion method were monitored to assess the stability of the scaffold in a physiological medium in a hydrated condition, and to assay its resistance against enzymatic forces. The scanning electron microscope (SEM) image of the scaffold samples showed porous architecture with gradual change in their morphology and reduced tensile properties with increasing aloe vera concentration. The FTIR spectrum revealed the overlap of the AV absorption peak with the absorption peak of COL-CS. The inclusion of AV to COL-CS increased the thermal stability as well as hydrophilicity of the scaffolds. Cell culture studies on the scaffold showed enhanced growth and proliferation of fibroblasts (3T3L1) without exhibiting any toxicity. Also, normal cell morphology and proliferation were observed by fluorescence microscopy and SEM. The rate of cell growth in the presence/absence of aloe vera in the scaffolds was in the order: COL-CS-AV > COL-CS > TCP (tissue culture polystyrene plate). These results suggested that the aloe vera gel-blended COL-CS scaffolds could be a promising candidate for tissue engineering applications.

  5. Chemical engineering and structural and pharmacological characterization of the α-scorpion toxin OD1.

    Science.gov (United States)

    Durek, Thomas; Vetter, Irina; Wang, Ching-I Anderson; Motin, Leonid; Knapp, Oliver; Adams, David J; Lewis, Richard J; Alewood, Paul F

    2013-01-01

    Scorpion α-toxins are invaluable pharmacological tools for studying voltage-gated sodium channels, but few structure-function studies have been undertaken due to their challenging synthesis. To address this deficiency, we report a chemical engineering strategy based upon native chemical ligation. The chemical synthesis of α-toxin OD1 was achieved by chemical ligation of three unprotected peptide segments. A high resolution X-ray structure (1.8 Å) of synthetic OD1 showed the typical βαββ α-toxin fold and revealed important conformational differences in the pharmacophore region when compared with other α-toxin structures. Pharmacological analysis of synthetic OD1 revealed potent α-toxin activity (inhibition of fast inactivation) at Nav1.7, as well as Nav1.4 and Nav1.6. In addition, OD1 also produced potent β-toxin activity at Nav1.4 and Nav1.6 (shift of channel activation in the hyperpolarizing direction), indicating that OD1 might interact at more than one site with Nav1.4 and Nav1.6. Investigation of nine OD1 mutants revealed that three residues in the reverse turn contributed significantly to selectivity, with the triple OD1 mutant (D9K, D10P, K11H) being 40-fold more selective for Nav1.7 over Nav1.6, while OD1 K11V was 5-fold more selective for Nav1.6 than Nav1.7. This switch in selectivity highlights the importance of the reverse turn for engineering α-toxins with altered selectivity at Nav subtypes.

  6. Geologic and Engineering Characterization of East Ford Field, Reeves County, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, Shirley P.; Flanders, William A.; Guzman, Jose I.; Zirczy, Helena

    1999-08-16

    The objective of this Class III project is to demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover a higher percentage of the original oil in place through geologically based field development. The project focused on reservoir characterization of the East Ford unit, a representative Delaware Mountain Group field that produces from the upper Bell Canyon Formation (Ramsey Sandstone). The field, discovered in 1960, is operated by Oral Petco, Inc., as the East Ford unit: it contained an estimated 18.4 million barrels (MMbbl) of original oil in place.

  7. Short-Term and Long-Term Technology Needs/Matching Status at Idaho National Engineering and Environmental Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    S. L. Claggett

    1999-12-01

    This report identifies potential technology deployment opportunities for the Environmental Management (EM) programs at the Idaho National Engineering and Environmental Laboratory (INEEL). The focus is on identifying candidates for Accelerated Site Technology Deployment (ASTD) proposals within the Environmental Restoration and Waste Management areas. The 86 technology needs on the Site Technology Coordination Group list were verified in the field. Six additional needs were found, and one listed need was no longer required. Potential technology matches were identified and then investigated for applicability, maturity, cost, and performance. Where promising, information on the technologies was provided to INEEL managers for evaluation. Eleven potential ASTD projected were identified, seven for near-term application and four for application within the next five years.

  8. The current status of iPS cells in cardiac research and their potential for tissue engineering and regenerative medicine.

    Science.gov (United States)

    Martins, Ana M; Vunjak-Novakovic, Gordana; Reis, Rui L

    2014-04-01

    The recent availability of human cardiomyocytes derived from induced pluripotent stem (iPS) cells opens new opportunities to build in vitro models of cardiac disease, screening for new drugs, and patient-specific cardiac therapy. Notably, the use of iPS cells enables studies in the wide pool of genotypes and phenotypes. We describe progress in reprogramming of induced pluripotent stem (iPS) cells towards the cardiac lineage/differentiation. The focus is on challenges of cardiac disease modeling using iPS cells and their potential to produce safe, effective and affordable therapies/applications with the emphasis of cardiac tissue engineering. We also discuss implications of human iPS cells to biological research and some of the future needs.

  9. Block copolymers : controlling nanostructure to generate functional materials : synthesis, characterization, and engineering

    OpenAIRE

    Epps, Thomas H.; O'Reilly, Rachel K.

    2016-01-01

    n this perspective, we survey recent advances in the synthesis and characterization of block copolymers, discuss several key materials opportunities enabled by block copolymers, and highlight some of the challenges that currently limit further realization of block copolymers in promising nanoscale applications. One significant challenge, especially as the complexity and functionality of designer macromolecules increases, is the requirement of multiple complementary techniques to fully charact...

  10. Geologic and engineering characterization of Geraldine Ford field, Reeves and Culberson Counties, Texas. Topical report -- 1997

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, S.P.; Malik, M.A.; Asquith, G.B.; Barton, M.D.; Cole, A.G.; Gogas, J.; Clift, S.J.; Guzman, J.I.

    1998-04-01

    The objective of this Class III project is to demonstrate that detailed reservoir characterization of clastic reservoirs in basinal sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover more of the original oil in place by strategic infill-well placement and geologically based field development. The study focused on Geraldine Ford field, which produces from the upper Bell Canyon formation (Ramsey sandstone). Petrophysical characterization of the Ford Geraldine unit was accomplished by integrating core and log data and quantifying petrophysical properties from wireline logs. The petrophysical data were used to map porosity, permeability, net pay, water saturation, mobile oil saturation, and other reservoir properties. Once the reservoir-characterization study was completed, a demonstration area of approximately 1 mi{sup 2} in the northern part of the unit was chosen for reservoir modeling/simulation. A quarter of a five-spot injection pattern in the demonstration area was selected for flow simulations, and two cases of permeability distribution were considered, one using stochastic permeability distribution generated by conditional simulation and the other using layered permeabilities. Flow simulations were performed using UTCOMP, an isothermal, three-dimensional, compositional simulator for miscible gas flooding. Results indicate that 10--30% (1 to 3 MMbbl) of remaining oil in place in the demonstration area can be produced by CO{sub 2} injection.

  11. Nanoimaging: photophysical and pharmaceutical characterization of poly-lactide-co-glycolide nanoparticles engineered with quantum dots

    Science.gov (United States)

    Pederzoli, F.; Ruozi, B.; Pracucci, E.; Signore, G.; Zapparoli, Mauro; Forni, F.; Vandelli, M. A.; Ratto, G.; Tosi, G.

    2016-01-01

    Quantum dots (QDs) and polymeric nanoparticles (NPs) are considered good binomials for the development of multifunctional nanomedicines for multimodal imaging. Fluorescent imaging of QDs can monitor the behavior of QD-labeled NPs in both cells and animals with high temporal and spatial resolutions. The comprehension of polymer interaction with the metallic QD surface must be considered to achieve a complete chemicophysical characterization of these systems and to describe the QD optical properties to be used for their unequivocal identification in the tissue. In this study, by comparing two different synthetic procedures to obtain polymeric nanoparticles labeled with QDs, we investigated whether their optical properties may change according to the formulation methods, as a consequence of the different polymeric environments. Atomic force microscopy, transmission electron microscopy, confocal and fluorescence lifetime imaging microscopy characterization demonstrated that NPs modified with QDs after the formulation process (post-NPs-QDs) conserved the photophysical features of the QD probe. In contrast, by using a polymer modified with QDs to formulate NPs (pre-NPs-QDs), a significant quenching of QD fluorescence and a blueshift in its emission spectra were observed. Our results suggest that the packaging of QDs into the polymeric matrix causes a modification of the QD optical properties: these effects must be characterized in depth and carefully considered when developing nanosystems for imaging and biological applications.

  12. Preparation and comparative characterization of keratin-chitosan and keratin-gelatin composite scaffolds for tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Balaji, S.; Kumar, Ramadhar; Sripriya, R.; Kakkar, Prachi; Ramesh, D. Vijaya [Bio-products Laboratory, Biomaterial Division (India); Reddy, P. Neela Kanta [Bioorganic and Neurochemistry Department, Central Leather Research Institute, Central Leather Research Institute, Adyar, Chennai-20 (India); Sehgal, P.K., E-mail: sehgal_pk@yahoo.co.in [Bio-products Laboratory, Biomaterial Division (India)

    2012-05-01

    We report fabrication of three dimensional scaffolds with well interconnected matrix of high porosity using keratin, chitosan and gelatin for tissue engineering and other biomedical applications. Scaffolds were fabricated using porous Keratin-Gelatin (KG), Keratin-Chitosan (KC) composites. The morphology of both KG and KC was investigated using SEM. The scaffolds showed high porosity with interconnected pores in the range of 20-100 {mu}m. They were further tested by FTIR, DSC, CD, tensile strength measurement, water uptake and swelling behavior. In vitro cell adhesion and cell proliferation tests were carried out to study the biocompatibility behavior and their application as an artificial skin substitute. Both KG and KC composite scaffolds showed similar properties and patterns for cell proliferation. Due to rapid degradation of gelatin in KG, we found that it has limited application as compared to KC scaffold. We conclude that KC scaffold owing to its slow degradation and antibacterial properties would be a better substrate for tissue engineering and other biomedical application. Highlights: Black-Right-Pointing-Pointer Extraction of reduced keratin from horn meal. Black-Right-Pointing-Pointer Preparation of keratin-gelatin and keratin-chitosan composite scaffolds. Black-Right-Pointing-Pointer Characterizations of the composite scaffolds. Black-Right-Pointing-Pointer Comparative cytotoxicity analysis on NIH3T3 fibroblasts.

  13. TRAIL-engineered pancreas-derived mesenchymal stem cells: characterization and cytotoxic effects on pancreatic cancer cells.

    Science.gov (United States)

    Moniri, M R; Sun, X-Y; Rayat, J; Dai, D; Ao, Z; He, Z; Verchere, C B; Dai, L-J; Warnock, G L

    2012-09-01

    Mesenchymal stem cells (MSCs) have attracted great interest in cancer therapy owing to their tumor-oriented homing capacity and the feasibility of autologous transplantation. Currently, pancreatic cancer patients face a very poor prognosis, primarily due to the lack of therapeutic strategies with an effective degree of specificity. Anticancer gene-engineered MSCs specifically target tumor sites and can produce anticancer agents locally and constantly. This study was performed to characterize pancreas-derived MSCs and investigate the effects of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-engineered MSCs on pancreatic cancer cells under different culture conditions. Pancreas-derived MSCs exhibited positive expression on CD44, CD73, CD95, CD105, negative on CD34 and differentiated into adipogenic and osteogenic cells. TRAIL expression was assessed by both enzyme-linked immunosorbent assay and western blot analysis. Different patterns of TRAIL receptor expression were observed on the pancreatic cancer cell lines, including PANC1, HP62, ASPC1, TRM6 and BXPC3. Cell viability was assessed using a real-time monitoring system. Pancreatic cancer cell death was proportionally related to conditioned media from MSC(nsTRAIL) and MSC(stTRAIL). The results suggest that MSCs exhibit intrinsic inhibition of pancreatic cancer cells and that this effect can be potentiated by TRAIL-transfection on death receptor-bearing cell types.

  14. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding.

    Science.gov (United States)

    Mi, Hao-Yang; Salick, Max R; Jing, Xin; Jacques, Brianna R; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

    2013-12-01

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications.

  15. A Fully Nonmetallic Gas Turbine Engine Enabled by Additive Manufacturing, Part II: Additive Manufacturing and Characterization of Polymer Composites

    Science.gov (United States)

    Chuang, Kathy C.; Grady, Joseph E.; Arnold, Steven M.; Draper, Robert D.; Shin, Eugene; Patterson, Clark; Santelle, Tom; Lao, Chao; Rhein, Morgan; Mehl, Jeremy

    2015-01-01

    This publication is the second part of the three part report of the project entitled "A Fully Nonmetallic Gas Turbine Engine Enabled by Additive Manufacturing" funded by NASA Aeronautics Research Institute (NARI). The objective of this project was to conduct additive manufacturing to produce aircraft engine components by Fused Deposition Modeling (FDM), using commercially available polyetherimides-Ultem 9085 and experimental Ultem 1000 mixed with 10% chopped carbon fiber. A property comparison between FDM-printed and injection molded coupons for Ultem 9085, Ultem 1000 resin and the fiber-filled composite Ultem 1000 was carried out. Furthermore, an acoustic liner was printed from Ultem 9085 simulating conventional honeycomb structured liners and tested in a wind tunnel. Composite compressor inlet guide vanes were also printed using fiber-filled Ultem 1000 filaments and tested in a cascade rig. The fiber-filled Ultem 1000 filaments and composite vanes were characterized by scanning electron microscope (SEM) and acid digestion to determine the porosity of FDM-printed articles which ranged from 25 to 31%. Coupons of Ultem 9085, experimental Ultem 1000 composites and XH6050 resin were tested at room temperature and 400F to evaluate their corresponding mechanical properties. A preliminary modeling was also initiated to predict the mechanical properties of FDM-printed Ultem 9085 coupons in relation to varied raster angles and void contents, using the GRC-developed MAC/GMC program.

  16. Quantitative Characterization of Configurational Space Sampled by HIV-1 Nucleocapsid Using Solution NMR, X-ray Scattering and Protein Engineering.

    Science.gov (United States)

    Deshmukh, Lalit; Schwieters, Charles D; Grishaev, Alexander; Clore, G Marius

    2016-06-03

    Nucleic-acid-related events in the HIV-1 replication cycle are mediated by nucleocapsid, a small protein comprising two zinc knuckles connected by a short flexible linker and flanked by disordered termini. Combining experimental NMR residual dipolar couplings, solution X-ray scattering and protein engineering with ensemble simulated annealing, we obtain a quantitative description of the configurational space sampled by the two zinc knuckles, the linker and disordered termini in the absence of nucleic acids. We first compute the conformational ensemble (with an optimal size of three members) of an engineered nucleocapsid construct lacking the N- and C-termini that satisfies the experimental restraints, and then validate this ensemble, as well as characterize the disordered termini, using the experimental data from the full-length nucleocapsid construct. The experimental and computational strategy is generally applicable to multidomain proteins. Differential flexibility within the linker results in asymmetric motion of the zinc knuckles which may explain their functionally distinct roles despite high sequence identity. One of the configurations (populated at a level of ≈40 %) closely resembles that observed in various ligand-bound forms, providing evidence for conformational selection and a mechanistic link between protein dynamics and function.

  17. Characterization, engineering, and reliability of nano-scale high-k dielectrics and semiconductors interfaces

    Science.gov (United States)

    Seo, Kang-Ill

    The continued scaling of silicon complementary metal-oxide-semiconductor devices has lead to a need to replace the SiO2 gate insulator with high-k dielectric oxides, such as ZrO2 and HfO 2-based materials, to maintain a smaller leakage current without losing electrostatic gate control of the channel region. The main objectives of this dissertation are to understand the physical and electronic structure of the high-k/semiconductor interfaces, and based on that understanding, to develop new techniques that can modify or passivate the high-k /semiconductor interfaces for improved performance and reliability. First, we investigated chemical bonding structures and valence band alignments at the high-k (HfO2) and semiconductor (Si, Ge) interfaces using Synchrotron radiation photoemission spectroscopy. We found that highly non-stoichiometric GeOx exists at the HfO2/Ge interface, while stoichiometric SiOx was analyzed at the HfO 2/Si interface. From the valence band spectra the valence band offsets between HfO2 and Si or Ge were determined. Second, we demonstrated that the Zr-silicate interfacial layer (IL) can be formed between ZrO2 and a Si substrate by controlling the solid state reaction between Zr and an underlying SiO2/Si substrate. Incorporation of the metal-silicate layer improved the electrical properties, and reduced the stack equivalent oxide thickness. We also determined changes in chemical bonding at the HfO2/Si interface and associated electrical properties after the SiO2 IL is gettered by a Ti metal overlayer. We found that the removal of a part of SiO2 IL by oxygen-gettering Ti electrodes may be a promising approach for engineering ultrathin EOT without provoking a significant increase in interface trap density. Finally, for the first time, we developed a new technique to incorporate fluorine in high-k stack (HfO2/SiO2), and discovered that the negative bias temperature instability problems, such as positive charge trapping, interface trap generation, and C

  18. PV LED ENGINE characterization lab for stand alone light-to-light systems

    DEFF Research Database (Denmark)

    Poulsen, Peter Behrensdorff; Thorsteinsson, Sune; Lindén, Johannes

    2015-01-01

    PV-powered lighting systems, light-to-light systems (L2L), offer outdoor lighting where it is elsewhere cumbersome to enable lighting. Application of these systems at high latitudes, where the difference in day length between summer and winter is large and the solar energy is low requires smart d...... are presented. Furthermore, a laboratory has been build to characterize these systems up to 200 Wp from “nose to tail” in great details to support improvement of the systems and to make accurate field performance predictions by the dimensioning tool....

  19. Extensive Characterization and Comparison of Endothelial Cells Derived from Dermis and Adipose Tissue: Potential Use in Tissue Engineering.

    Science.gov (United States)

    Monsuur, Hanneke N; Weijers, Ester M; Niessen, Frank B; Gefen, Amit; Koolwijk, Pieter; Gibbs, Susan; van den Broek, Lenie J

    2016-01-01

    Tissue-engineered constructs need to become quickly vascularized in order to ensure graft take. One way of achieving this is to incorporate endothelial cells (EC) into the construct. The adipose tissue stromal vascular fraction (adipose-SVF) might provide an alternative source for endothelial cells as adipose tissue can easily be obtained by liposuction. Since adipose-EC are now gaining more interest in tissue engineering, we aimed to extensively characterize endothelial cells from adipose tissue (adipose-EC) and compare them with endothelial cells from dermis (dermal-EC). The amount of endothelial cells before purification varied between 4-16% of the total stromal population. After MACS selection for CD31 positive cells, a >99% pure population of endothelial cells was obtained within two weeks of culture. Adipose- and dermal-EC expressed the typical endothelial markers PECAM-1, ICAM-1, Endoglin, VE-cadherin and VEGFR2 to a similar extent, with 80-99% of the cell population staining positive. With the exception of CXCR4, which was expressed on 29% of endothelial cells, all other chemokine receptors (CXCR1, 2, 3, and CCR2) were expressed on less than 5% of the endothelial cell populations. Adipose-EC proliferated similar to dermal-EC, but responded less to the mitogens bFGF and VEGF. A similar migration rate was found for both adipose-EC and dermal-EC in response to bFGF. Sprouting of adipose-EC and dermal-EC was induced by bFGF and VEGF in a 3D fibrin matrix. After stimulation of adipose-EC and dermal-EC with TNF-α an increased secretion was seen for PDGF-BB, but not uPA, PAI-1 or Angiopoietin-2. Furthermore, secretion of cytokines and chemokines (IL-6, CCL2, CCL5, CCL20, CXCL1, CXCL8 and CXCL10) was also upregulated by both adipose- and dermal-EC. The similar characteristics of adipose-EC compared to their dermal-derived counterpart make them particularly interesting for skin tissue engineering. In conclusion, we show here that adipose tissue provides for an

  20. Dynamic characterization of partially saturated engineered porous media and gas diffusion layers using hydraulic admittance

    Science.gov (United States)

    Cheung, Perry; Fairweather, Joseph D.; Schwartz, Daniel T.

    2012-09-01

    Simple laboratory methods for determining liquid water distribution in polymer electrolyte membrane fuel cell gas diffusion layers (GDLs) are needed to engineer better GDL materials. Capillary pressure vs. liquid saturation measurements are attractive, but lack the ability to probe the hydraulic interconnectivity and distribution within the pore structure. Hydraulic admittance measurements of simple capillary bundles have recently been shown to nicely measure characteristics of the free-interfaces and hydraulic path. Here we examine the use of hydraulic admittance with a succession of increasingly complex porous media, starting with a laser-drilled sample with 154 asymmetric pores and progress to the behavior of Toray TGP-H090 carbon papers. The asymmetric laser-drilled sample clearly shows hydraulic admittance measurements are sensitive to sample orientation, especially when examined as a function of saturation state. Finite element modeling of the hydraulic admittance is consistent with experimental measurements. The hydraulic admittance spectra from GDL samples are complex, so we examine trends in the spectra as a function of wet proofing (0% and 40% Teflon loadings) as well as saturation state of the GDL. The presence of clear peaks in the admittance spectra for both GDL samples suggests a few pore types are largely responsible for transporting liquid water.

  1. Preparation and characterization of chitosan-natural nano hydroxyapatite-fucoidan nanocomposites for bone tissue engineering.

    Science.gov (United States)

    Lowe, Baboucarr; Venkatesan, Jayachandran; Anil, Sukumaran; Shim, Min Suk; Kim, Se-Kwon

    2016-12-01

    Solid three dimensional (3D) composite scaffolds for bone tissue engineering were prepared using the freeze-drying method. The scaffolds were composed of chitosan, natural nano-hydroxyapatite (nHA) and fucoidan in the following combinations: chitosan, chitosan-fucoidan, chitosan-nHA, and chitosan-nHA-fucoidan. Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and optical microscopy (OM) were used to determine the physiochemical constituents and the morphology of the scaffolds. The addition of nHA into the chitosan-fucoidan composite scaffold reduced the water uptake and water retention. FT-IR analysis confirmed the presence of a phosphate group in the chitosan-nHA-fucoidan scaffold. This group is present because of the presence of nHA (isolated via alkaline hydrolysis from salmon fish bones). Microscopic results indicated that the dispersion of nHA and fucoidan in the chitosan matrix was uniform with a pore size of 10-400μm. The composite demonstrated a suitable micro architecture for cell growth and nutrient supplementation. This compatibility was further elucidated in vitro using periosteum-derived mesenchymal stem cells (PMSCs). The cells demonstrated high biocompatibility and excellent mineralization for the chitosan-nHA-fucoidan scaffold. We believe that a chitosan-nHA-fucoidan composite is a promising biomaterial for the scaffold that can be used for bone tissue regeneration.

  2. Synthesis, characterization and in vitro cytotoxicity assessment of hydroxyapatite from different bioresources for tissue engineering application

    Indian Academy of Sciences (India)

    Sudip Mondal; Rajashree Bardhan; Biswanath Mondal; Apurba Dey; Sudit S Mukhopadhyay; Syamal Roy; Rajan Guha; Koushik Roy

    2012-08-01

    In the present study, hydroxyapatite (HAp) is synthesized from different biosources like eggshell, fish scale and bovine bone in a cost effective and ecofriendly way. HAp materials were synthesized from eggshell by wet precipitation method whereas thermal decomposition method was applied in case of fish scale and bovine bone. The phase purity and crystallinity of different calcined HAp powder were determined by XRD and FTIR analyses. The thermogravimetric analysis was carried out to show thermal stability of HAp powder. Average grain sizes of sintered samples were in submicron range. The morphology of the powders were observed under scanning electron microscopy (SEM). The dried powders were wet ball milled for several hours and surfactants like Triton-X small fillers (2 / 4 mm long rod-shaped) were made for in vitro testing. In order to verify the biocompatibility of HAp powders, cytotoxicity evaluation was carried out in RAW macrophage like cell line media for an incubation period of 72 h. The cell attachment studies on HAp compacts show an excellent affinity between cells and compact surface. These results proved high biocompatibility of HAp powders obtained fromdifferent biosources for tissue engineering applications.

  3. Characterization of Bone Marrow Mononuclear Cells on Biomaterials for Bone Tissue Engineering In Vitro

    Directory of Open Access Journals (Sweden)

    Dirk Henrich

    2015-01-01

    Full Text Available Bone marrow mononuclear cells (BMCs are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma, demineralized bone matrix (DBM, and bovine cancellous bone (BS were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo.

  4. Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques

    Directory of Open Access Journals (Sweden)

    Birmania Heredia Rivera

    2016-10-01

    Full Text Available Particulate matter accumulated on car engine air-filters (CAFs was examined in order to investigate the potential use of these devices as efficient samplers for collecting street level air that people are exposed to. The morphology, microstructure, and chemical composition of a variety of particles were studied using scanning electron microscopy (SEM and energy-dispersive X-ray (EDX. The particulate matter accumulated by the CAFs was studied in two categories; the first was of removed particles by friction, and the second consisted of particles retained on the filters. Larger particles with a diameter of 74–10 µm were observed in the first category. In the second one, the detected particles had a diameter between 16 and 0.7 µm. These particles exhibited different morphologies and composition, indicating mostly a soil origin. The elemental composition revealed the presence of three groups: mineral (clay and asphalt, metallic (mainly Fe, and biological particles (vegetal and animal debris. The palynological analysis showed the presence of pollen grains associated with urban plants. These results suggest that CAFs capture a mixture of atmospheric particles, which can be analyzed in order to monitor urban air. Thus, the continuous availability of large numbers of filters and the retroactivity associated to the car routes suggest that these CAFs are very useful for studying the high traffic zones within a city.

  5. Production characterization and working characteristics in DICI engine of Pongamia biodiesel.

    Science.gov (United States)

    Srinivasa Rao, M; Anand, R B

    2015-11-01

    Renewable energy plays a predominant role in solving the current energy requirement problems and biodiesel is a promising alternative fuel to tide over the energy crisis and conserve fossil fuels. The present work investigates an eco-friendly substitute for the replacement of fossil fuels and the experiments are designed to determine the effects of a catalyst in the biodiesel production processes. Pongamia pinnata oil was utilized to produce the biodiesel by using catalysts namely KOH and NaOH and the properties of the fuel were found by using Carbon Hydrogen Nitrogen Sulfur (CHNS) elemental analysis, Fourier Transform Infrared (FTIR) Spectroscopy, Gas Chromatography & Mass Spectrometry (GC-MS), and Proton Nuclear Magnetic Resonance ((1)H NMR) Spectroscopy and the thermophysical properties were compared with those of neat diesel. In continuation, the working characteristics of the biodiesel and biodiesel-water emulsions were accomplished in a four stroke compression ignition engine and the results were compared to those of neat diesel. It was found that the exhaust emission characteristics like brake specific carbon monoxide (BSCO), brake specific hydrocarbons (BSHC) and smoke opacity were better for neat biodiesel (except brake specific nitric oxide BSNO) than those of neat diesel.

  6. Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques

    Science.gov (United States)

    Heredia Rivera, Birmania; Gerardo Rodriguez, Martín

    2016-01-01

    Particulate matter accumulated on car engine air-filters (CAFs) was examined in order to investigate the potential use of these devices as efficient samplers for collecting street level air that people are exposed to. The morphology, microstructure, and chemical composition of a variety of particles were studied using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The particulate matter accumulated by the CAFs was studied in two categories; the first was of removed particles by friction, and the second consisted of particles retained on the filters. Larger particles with a diameter of 74–10 µm were observed in the first category. In the second one, the detected particles had a diameter between 16 and 0.7 µm. These particles exhibited different morphologies and composition, indicating mostly a soil origin. The elemental composition revealed the presence of three groups: mineral (clay and asphalt), metallic (mainly Fe), and biological particles (vegetal and animal debris). The palynological analysis showed the presence of pollen grains associated with urban plants. These results suggest that CAFs capture a mixture of atmospheric particles, which can be analyzed in order to monitor urban air. Thus, the continuous availability of large numbers of filters and the retroactivity associated to the car routes suggest that these CAFs are very useful for studying the high traffic zones within a city. PMID:27706087

  7. In vitro and in vivo analysis and characterization of engineered spinal neural implants (Conference Presentation)

    Science.gov (United States)

    Shor, Erez; Shoham, Shy; Levenberg, Shulamit

    2016-03-01

    Spinal cord injury is a devastating medical condition. Recent developments in pre-clinical and clinical research have started to yield neural implants inducing functional recovery after spinal cord transection injury. However, the functional performance of the transplants was assessed using histology and behavioral experiments which are unable to study cell dynamics and the therapeutic response. Here, we use neurophotonic tools and optogenetic probes to investigate cellular level morphology and activity characteristics of neural implants over time at the cellular level. These methods were used in-vitro and in-vivo, in a mouse spinal cord injury implant model. Following previous attempts to induce recovery after spinal cord injury, we engineered a pre-vascularized implant to obtain better functional performance. To image network activity of a construct implanted in a mouse spinal cord, we transfected the implant to express GCaMP6 calcium activity indicators and implanted these constructs under a spinal cord chamber enabling 2-photon chronic in vivo neural activity imaging. Activity and morphology analysis image processing software was developed to automatically quantify the behavior of the neural and vascular networks. Our experimental results and analyses demonstrate that vascularized and non-vascularized constructs exhibit very different morphologic and activity patterns at the cellular level. This work enables further optimization of neural implants and also provides valuable tools for continuous cellular level monitoring and evaluation of transplants designed for various neurodegenerative disease models.

  8. PCL/alginate composite scaffolds for hard tissue engineering: fabrication, characterization, and cellular activities.

    Science.gov (United States)

    Kim, Yong Bok; Kim, Geun Hyung

    2015-02-09

    Alginates have been used widely in biomedical applications because of good biocompatibility, low cost, and rapid gelation in the presence of calcium ions. However, poor mechanical properties and fabrication-ability for three-dimensional shapes have been obstacles in hard-tissue engineering applications. To overcome these shortcomings of alginates, we suggest a new composite system, consisting of a synthetic polymer, poly(ε-caprolactone), and various weight fractions (10-40 wt %) of alginate. The fabricated composite scaffolds displayed a multilayered 3D structure, consisting of microsized composite struts, and they provided a 100% offset for each layer. To show the feasibility of the scaffold for hard tissue regeneration, the composite scaffolds fabricated were assessed not only for physical properties, including surface roughness, tensile strength, and water absorption and wetting, but also in vitro osteoblastic cellular responses (cell-seeding efficiency, cell viability, fluorescence analyses, alkaline phosphatase (ALP) activity, and mineralization) by culturing with preosteoblasts (MC3T3-E1). Due to the alginate components in the composites, the scaffolds showed significantly enhanced wetting behavior, water-absorption (∼12-fold), and meaningful biological activities (∼2.1-fold for cell-seeding efficiency, ∼2.5-fold for cell-viability at 7 days, ∼3.4-fold for calcium deposition), compared with a pure PCL scaffold.

  9. Preparation and Characterization of a Novel Decellularized Fibrocartilage "Book" Scaffold for Use in Tissue Engineering.

    Directory of Open Access Journals (Sweden)

    Liyun Guo

    Full Text Available At the tendon-to-bone insertion, there is a unique transitional structure: tendon, non-calcified fibrocartilage, calcified fibrocartilage, and bone. The reconstruction of this special graded structure after defects or damage is an important but challenging task in orthopedics. In particular, reconstruction of the fibrocartilage zone has yet to be successfully achieved. In this study, the development of a novel book-shape scaffold derived from the extracellular matrix of fibrocartilage was reported. Specifically, fibrocartilage from the pubic symphysis was obtained from rabbits and sliced into the shape of a book (dimensions: 10 mm × 3 mm × 1 mm with 10 layers, each layer (akin to a page of a book with a thickness of 100-μm. These fibrocartilage "book" scaffolds were decellularized using sequentially 3 freeze-thaw cycles, 0.1% Triton X-100 with 1.5 M KCl, 0.25% trypsin, and a nuclease. Histology and DNA quantification analysis confirmed substantial removal of cells from the fibrocartilage scaffolds. Furthermore, the quantities of DNA, collagen, and glycosaminoglycan in the fibrocartilage were markedly reduced following decellularization. Scanning electron microscopy confirmed that the intrinsic ultrastructure of the fibrocartilage tissue was well preserved. Therefore, the results of this study suggest that the novel "book" fibrocartilage scaffold could have potential applications in tissue engineering.

  10. Characterization and mechanical performance study of silk/PVA cryogels: towards nucleus pulposus tissue engineering.

    Science.gov (United States)

    Neo, Puay Yong; Shi, Pujiang; Goh, James Cho-Hong; Toh, Siew Lok

    2014-10-20

    Poly (vinyl) alcohol (PVA) cryogels are reported in the literature for application in nucleus pulposus (NP) replacement strategies. However, these studies are mainly limited to acellular approaches-in part due to the high hydrophilicity of PVA gels that renders cellular adhesion difficult. Silk is a versatile biomaterial with excellent biocompatibility. We hypothesize that the incorporation of silk with PVA will (i) improve the cell-hosting abilities of PVA cryogels and (ii) allow better tailoring of physical properties of the composite cryogels for an NP tissue engineering purpose. 5% (wt/vol) PVA is blended with 5% silk fibroin (wt/vol) to investigate the effect of silk : PVA ratios on the cryogels' physical properties. Results show that the addition of silk results in composite cryogels that are able to swell to more than 10 times its original dry weight and rehydrate to at least 70% of its original wet weight. Adding at least 20% silk significantly improves surface hydrophobicity and is correlated with an improvement in cell-hosting abilities. Cell-seeded cryogels also display an increment in compressive modulus and hoop stress values. In all, adding silk to PVA creates cryogels that can be potentially used as NP replacements.

  11. Grout testing and characterization for shallow-land burial trenches at the Idaho National Engineering Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Tallent, O.K.; Sams, T.L.; Tamura, T.; Godsey, T.T.; Francis, C.L.; McDaniel, E.W.

    1986-10-01

    An investigation was conducted to develop grout formulations suitable for in situ stabilization of low-level and transuranic (TRU) waste in shallow-land burial trenches at Idaho National Engineering Laboratory (INEL). The acceptabilities of soil, ordinary particulate, and fine particulate grouts were evaluated based on phase separation, compressive strength, freeze/thaw, penetration resistance, rheological, water permeability, column, and other tests. Soil grouts with soil-to-cement weight ratios from 0.91 to 1.60 were found to be suitable for open trench or drum disposal. Ordinary particulate grouts containing type I,II Portland cement, class C fly ash, bentonite, water, and a fluidizer were formulated to fill large voids within the soil/waste matrix of a closed shallow-land burial trench. Fine particulate grouts containing fine (mean particle size, 9.6 m) cement and water were formulated to fill smaller voids and to establish a grout-soil barrier to prevent water intrusion into the grouted waste trench. Solution, or chemical grouts, were evaluated as possible substitutes for the fine particulate grouts.

  12. Preparation and characterization of bionic bone structure chitosan/hydroxyapatite scaffold for bone tissue engineering.

    Science.gov (United States)

    Zhang, Jiazhen; Nie, Jingyi; Zhang, Qirong; Li, Youliang; Wang, Zhengke; Hu, Qiaoling

    2014-01-01

    Three-dimensional oriented chitosan (CS)/hydroxyapatite (HA) scaffolds were prepared via in situ precipitation method in this research. Scanning electron microscopy (SEM) images indicated that the scaffolds with acicular nano-HA had the spoke-like, multilayer and porous structure. The SEM of osteoblasts which were polygonal or spindle-shaped on the composite scaffolds after seven-day cell culture showed that the cells grew, adhered, and spread well. The results of X-ray powder diffractometer and Fourier transform infrared spectrometer showed that the mineral particles deposited in the scaffold had phase structure similar to natural bone and confirmed that particles were exactly HA. In vitro biocompatibility evaluation indicated the composite scaffolds showed a higher degree of proliferation of MC3T3-E1 cell compared with the pure CS scaffolds and the CS/HA10 scaffold was the highest one. The CS/HA scaffold also had a higher ratio of adhesion and alkaline phosphate activity value of osteoblasts compared with the pure CS scaffold, and the ratio increased with the increase of HA content. The ALP activity value of composite scaffolds was at least six times of the pure CS scaffolds. The results suggested that the composite scaffolds possessed good biocompatibility. The compressive strength of CS/HA15 increased by 33.07% compared with the pure CS scaffold. This novel porous scaffold with three-dimensional oriented structure might have a potential application in bone tissue engineering.

  13. Engineering and Characterization of a Fluorescent Native-Like HIV-1 Envelope Glycoprotein Trimer

    Directory of Open Access Journals (Sweden)

    Kwinten Sliepen

    2015-10-01

    Full Text Available Generation of a stable, soluble mimic of the HIV-1 envelope glycoprotein (Env trimer on the virion surface has been considered an important first step for developing a successful HIV-1 vaccine. Recently, a soluble native-like Env trimer (BG505 SOSIP.664 has been described. This protein has facilitated major advances in the HIV-1 vaccine field, since it was the first Env immunogen that induced consistent neutralizing antibodies against a neutralization-resistant (tier 2 virus. Moreover, BG505 SOSIP.664 enabled elucidation of the atomic resolution structure of the Env trimer and facilitated the isolation and characterization of new broadly neutralizing antibodies against HIV-1. Here, we designed and characterized the BG505 SOSIP.664 trimer fused to fluorescent superfolder GFP (sfGFP, a GFP variant that allows efficient folding (BG505 SOSIP.664-sfGFP. Despite the presence of the sfGFP, the Env protein largely retained its morphology, antigenicity, glycan composition, and thermostability. In addition, we show that BG505 SOSIP.664-sfGFP can be used for fluorescence-based assays, such as flow cytometry.

  14. Novel isolation and biochemical characterization of immortalized fibroblasts for tissue engineering vocal fold lamina propria.

    Science.gov (United States)

    Chen, Xia; Thibeault, Susan L

    2009-06-01

    Tissue regeneration of the vocal fold lamina propria extracellular matrix (ECM) will be facilitated by the use of suitable vocal fold fibroblast (VFF) cell lines in appropriate model systems. Primary human VFFs (hVFFs) were steadily transduced by a retroviral vector containing human telomerase reverse transcriptase (hTERT) gene; immortalized cells grew and divided vigorously for more than 120 days. Biochemical characterization of the six transduced lines included, at different time points, expression of hTERT, telomerase activity, telomere lengths, and transcript levels of ECM constituents. Telomere lengths of the transfected lines were elongated and stable. Gene expression levels of collagen Ialpha1, collagen Ialpha2, collagen VIalpha3, elastin, and fibronectin were measured between the transduced cell clones and the primary hVFFs to verify transcription. Absence of inter- and intraspecies contamination was confirmed with DNA fingerprinting and karyotype analysis. Cell morphology, growth, and transcription expression were examined on 2D scaffolds-collagen, fibronectin, and hyaluronic acid. Immortalized hVFFs demonstrated normal attachment and spread on 2D scaffolds. Collagen Ialpha1, collagen Ialpha2, collagen VIalpha3, elastin, and fibronectin transcript expression was measured from immortalized hVFFs, for all surfaces. This is the first report of immortalization and biochemical characterization of hVFFs, providing a novel and invaluable tool for tissue regeneration applications in the larynx.

  15. Highly active engineered-enzyme oriented monolayers: formation, characterization and sensing applications

    Directory of Open Access Journals (Sweden)

    Patolsky Fernando

    2011-06-01

    Full Text Available Abstract Background The interest in introducing ecologically-clean, and efficient enzymes into modern industry has been growing steadily. However, difficulties associated with controlling their orientation, and maintaining their selectivity and reactivity is still a significant obstacle. We have developed precise immobilization of biomolecules, while retaining their native functionality, and report a new, fast, easy, and reliable procedure of protein immobilization, with the use of Adenylate kinase as a model system. Methods Self-assembled monolayers of hexane-1,6-dithiol were formed on gold surfaces. The monolayers were characterized by contact-angle measurements, Elman-reagent reaction, QCM, and XPS. A specifically designed, mutated Adenylate kinase, where cysteine was inserted at the 75 residue, and the cysteine at residue 77 was replaced by serine, was used for attachment to the SAM surface via spontaneously formed disulfide (S-S bonds. QCM, and XPS were used for characterization of the immobilized protein layer. Curve fitting in XPS measurements used a Gaussian-Lorentzian function. Results and Discussion Water contact angle (65-70°, as well as all characterization techniques used, confirmed the formation of self-assembled monolayer with surface SH groups. X-ray photoelectron spectroscopy showed clearly the two types of sulfur atom, one attached to the gold (triolate and the other (SH/S-S at the ω-position for the hexane-1,6-dithiol SAMs. The formation of a protein monolayer was confirmed using XPS, and QCM, where the QCM-determined amount of protein on the surface was in agreement with a model that considered the surface area of a single protein molecule. Enzymatic activity tests of the immobilized protein confirmed that there is no change in enzymatic functionality, and reveal activity ~100 times that expected for the same amount of protein in solution. Conclusions To the best of our knowledge, immobilization of a protein by the method

  16. Characterization of a genetically engineered mouse model of hemophilia A with complete deletion of the F8 gene.

    Science.gov (United States)

    Chao, B N; Baldwin, W H; Healey, J F; Parker, E T; Shafer-Weaver, K; Cox, C; Jiang, P; Kanellopoulou, C; Lollar, P; Meeks, S L; Lenardo, M J

    2016-02-01

    ESSENTIALS: Anti-factor VIII (FVIII) inhibitory antibody formation is a severe complication in hemophilia A therapy. We genetically engineered and characterized a mouse model with complete deletion of the F8 coding region. F8(TKO) mice exhibit severe hemophilia, express no detectable F8 mRNA, and produce FVIII inhibitors. The defined background and lack of FVIII in F8(TKO) mice will aid in studying FVIII inhibitor formation. The most important complication in hemophilia A treatment is the development of inhibitory anti-Factor VIII (FVIII) antibodies in patients after FVIII therapy. Patients with severe hemophilia who express no endogenous FVIII (i.e. cross-reacting material, CRM) have the greatest incidence of inhibitor formation. However, current mouse models of severe hemophilia A produce low levels of truncated FVIII. The lack of a corresponding mouse model hampers the study of inhibitor formation in the complete absence of FVIII protein. We aimed to generate and characterize a novel mouse model of severe hemophilia A (designated the F8(TKO) strain) lacking the complete coding sequence of F8 and any FVIII CRM. Mice were created on a C57BL/6 background using Cre-Lox recombination and characterized using in vivo bleeding assays, measurement of FVIII activity by coagulation and chromogenic assays, and anti-FVIII antibody production using ELISA. All F8 exonic coding regions were deleted from the genome and no F8 mRNA was detected in F8(TKO) mice. The bleeding phenotype of F8(TKO) mice was comparable to E16 mice by measurements of factor activity and tail snip assay. Similar levels of anti-FVIII antibody titers after recombinant FVIII injections were observed between F8(TKO) and E16 mice. We describe a new C57BL/6 mouse model for severe hemophilia A patients lacking CRM. These mice can be directly bred to the many C57BL/6 strains of genetically engineered mice, which is valuable for studying the impact of a wide variety of genes on FVIII inhibitor formation on a

  17. Biocompatible multilayer capsules engineered with a graphene oxide derivative: synthesis, characterization and cellular uptake

    Science.gov (United States)

    Del Mercato, Loretta L.; Guerra, Flora; Lazzari, Gianpiero; Nobile, Concetta; Bucci, Cecilia; Rinaldi, Rosaria

    2016-03-01

    Graphene-based capsules have strong potential for a number of applications, including drug/gene delivery, tissue engineering, sensors, catalysis and reactors. The ability to integrate graphene into carrier systems with three-dimensional (3D) geometry may open new perspectives both for fundamental tests of graphene mechanics and for novel (bio)technological applications. However, the assembly of 3D complexes from graphene or its derivatives is challenging because of its poor stability under biological conditions. In this work, we attempted to integrate a layer of graphene oxide derivative into the shell of biodegradable capsules by exploiting a facile layer-by-layer (LbL) protocol. As a first step we optimized the LbL protocol to obtain colloidal suspensions of isolated capsules embedding the graphene oxide derivative. As a following step, we investigated in detail the morphological properties of the hybrid capsules, and how the graphene oxide derivative layer influences the porosity and the robustness of the multilayer composite shells. Finally, we verified the uptake of the capsules modified with the GO derivative by two cell lines and studied their intracellular localization and biocompatibility. As compared to pristine capsules, the graphene-modified capsules possess reduced porosity, reduced shell thickness and a higher stability against osmotic pressure. They show remarkable biocompatibility towards the tested cells and long-term colloidal stability and dispersion. By combining the excellent mechanical properties of a graphene oxide derivative with the high versatility of the LbL method, robust and flexible biocompatible polymeric capsules with novel characteristics have been fabricated.Graphene-based capsules have strong potential for a number of applications, including drug/gene delivery, tissue engineering, sensors, catalysis and reactors. The ability to integrate graphene into carrier systems with three-dimensional (3D) geometry may open new perspectives

  18. Seismic characterization of select engineered nanoparticles in essentially saturated glass beads

    Science.gov (United States)

    Rajabdeen, Mohamed Nihad

    2011-12-01

    A laboratory testing apparatus was developed for the study of seismic body wave propagation through nanoparticles dispersed in pore fluid that is essentially saturating glass beads. First, the responses of water-saturated glass bead specimens were studied to establish baseline signatures. Then the seismic responses in the presence of engineered nanoparticles of various concentrations dispersed in the pore fluid of the specimen chamber were studied to observe variances from baseline. The testing apparatus incorporates piezoceramic bender elements to actuate and receive seismic body waves through a cylindrical column filled with glass beads and back-saturated at ambient pressure with liquid. The system was calibrated in air, water, and water-saturated glass beads. System repeatability was checked after the system was saturated and flushed once to soak and seat the beads. The water-saturated glass bead specimens were tested for compression, shear, and spectral response, from which baseline signatures were established. Criteria were proposed to evaluate the detectability of nanoparticle dispersions. Nanoparticle dispersions of zinc oxide (nZnO), titanium dioxide (nTiO 2), and silver (nAg) were tested. The testing system showed itself to be capable of registering subtle changes in the response caused by varying consolidation states of the glass beads and pore fluid content. The presence of nZnO was detectable for all the test methods except compression wave arrivals, nAg was detectable only by compression wave amplitude and spectral response and nTiO2 showed only subtle detectability for spectral response.

  19. Surface engineering and characterization of quantum dots and its application in living cell imaging

    Directory of Open Access Journals (Sweden)

    Han QIU

    2016-06-01

    Full Text Available Objective  Surface modification of hydrophobic nanoparticles is a key process for their application in the biological medicine fields. The aim of present study is to prepare the immunofluorescent probes by conjugation of hydrophilic surface-engineered quantum dots (QDs and monoclonal antibody for use of fluorescence labeled cells tracing. Methods  The bovine serum albumin (BSA with excellent water-solubility and biocompatibility was employed as the emulsifying agent, and used for surface modification of hydrophobic QDs under ultrasonication. The diameter, fluorescence spectrum and cytotoxicity of BSA-coated QDs (BSA-triP.QDs were analyzed. Then the BSA-coated QDs were conjugated with trastuzumab, which can be recognized and bound specifically to HER2. SKBR-3 breast cancer cells, with over-expression of HER-2, were labeled with hydrophilic QDstrastuzumab and imaged on a fluorescence planar imaging system. Results  The experimental results revealed that BSA as the emulsifying agent, combined with other polymers, can effectively phase transfer hydrophobic QDs. The BSA functionalized QDs exhibited excellent colloidal stability with fine hydrodynamic size distribution (about 70nm in a wide range of pH and ionic strengths values. Moreover, no significant cytotoxic effect was observed in SKBR-3 cells treated with BSA-coated QDs. After being coupled with trastuzumab, the hydrophilic QDs can be used as an immunofluorescence probe for HER2-positive breast cancer cell imaging. Conclusions  The advantages of BSA-coated QDs include straight forward synthesis, high colloidal stability, and promising immunofluorescence characteristic when coupled with specific antibody. These are therefore proved to be ideal nano systems for biomedical labeling, targeting, and imaging. DOI: 10.11855/j.issn.0577-7402.2016.05.04

  20. Characterizing the Transport of a Novel, Engineered Nanoparticle for Use in Remediation of Hydrophobic Contaminants

    Science.gov (United States)

    Sanders, J. E.; Miller, G. R.

    2015-12-01

    Magnetic shell crosslinked knedel-like nanoparticles (MSCKs) were originally engineered to aid in the cleanup of oil spills. These polymeric particles are spherical and approximately 70 nm in diameter. MSCKs have a hydrophobic shell and hydrophilic core which encapsulates suspended iron oxide nanoparticles, rendering them magnetic. MSCKs operate like discrete surfactant packets: increasing the mobility and apparent solubility of hydrophobic species, but do so within the confines of discrete particles which can then be recovered by filtration or magnetic removal. MSCKs accomplish this via sequestration of hydrophobic species from through the hydrophilic shell and into the hydrophobic core where hydrocarbon contaminants are entropically stabilized. In batch reactor testing, MSCKs have been shown to sequester crude oil up to ten times their mass (1000 mg of oil per 100 mg of MSCKs). This study examines the transport characteristics and contaminant sequestration capabilities of MSCKs in saturated porous media, in order to establish their potential for use in groundwater remediation. Baseline MSCK transport parameters were determined via one dimensional impulse column experiments. MSCKs were readily transported in saturated sand, with an average recovery rate of 99%. In the presence of 10% clay particles, recovery was reduced to 68%. MSCKs were able to completely sequester an aqueous phase pollutant (8.7 mg/L m-xylene), although it further reduced their recovery rate to 61% in sand and 53% in clay. The presence of a free phase contaminant (5% of pore space occupied by mineral oil) reduced MSCKs recovery in sand to 53%. The MSCKs recovered in the effluent had sequestered the mineral at ratios far below their capability (3-10 mg of oil per 100 mg of MSCKs). Overall, this study indicated that MSCKs show a number of promising attributes for use in remediation. However, further manipulation of their chemical and morphological properties is needed, with the objective of

  1. Biocompatible multilayer capsules engineered with a graphene oxide derivative: synthesis, characterization and cellular uptake.

    Science.gov (United States)

    del Mercato, Loretta L; Guerra, Flora; Lazzari, Gianpiero; Nobile, Concetta; Bucci, Cecilia; Rinaldi, Rosaria

    2016-04-14

    Graphene-based capsules have strong potential for a number of applications, including drug/gene delivery, tissue engineering, sensors, catalysis and reactors. The ability to integrate graphene into carrier systems with three-dimensional (3D) geometry may open new perspectives both for fundamental tests of graphene mechanics and for novel (bio)technological applications. However, the assembly of 3D complexes from graphene or its derivatives is challenging because of its poor stability under biological conditions. In this work, we attempted to integrate a layer of graphene oxide derivative into the shell of biodegradable capsules by exploiting a facile layer-by-layer (LbL) protocol. As a first step we optimized the LbL protocol to obtain colloidal suspensions of isolated capsules embedding the graphene oxide derivative. As a following step, we investigated in detail the morphological properties of the hybrid capsules, and how the graphene oxide derivative layer influences the porosity and the robustness of the multilayer composite shells. Finally, we verified the uptake of the capsules modified with the GO derivative by two cell lines and studied their intracellular localization and biocompatibility. As compared to pristine capsules, the graphene-modified capsules possess reduced porosity, reduced shell thickness and a higher stability against osmotic pressure. They show remarkable biocompatibility towards the tested cells and long-term colloidal stability and dispersion. By combining the excellent mechanical properties of a graphene oxide derivative with the high versatility of the LbL method, robust and flexible biocompatible polymeric capsules with novel characteristics have been fabricated.

  2. Toxicological characterization of diesel engine emissions using biodiesel and a closed soot filter

    Science.gov (United States)

    Kooter, Ingeborg M.; van Vugt, Marcel A. T. M.; Jedynska, Aleksandra D.; Tromp, Peter C.; Houtzager, Marc M. G.; Verbeek, Ruud P.; Kadijk, Gerrit; Mulderij, Mariska; Krul, Cyrille A. M.

    2011-03-01

    This study was designed to determine the toxicity (oxidative stress, cytotoxicity, genotoxicity) in extracts of combustion aerosols. A typical Euro III heavy truck engine was tested over the European Transient Cycle with three different fuels: conventional diesel EN590, biodiesel EN14214 as B100 and blends with conventional diesel (B5, B10, and B20) and pure plant oil DIN51605 (PPO). In addition application of a (wall flow) diesel particulate filter (DPF) with conventional diesel EN590 was tested. The use of B100 or PPO as a fuel or the DPF reduced particulate matter (PM) mass and numbers over 80%. Similarly, significant reduction in the emission of chemical constituents (EC 90%, (oxy)-PAH 70%) were achieved. No significant changes in nitro-PAH were observed. The use of B100 or PPO led to a NOx increase of about 30%, and no increase for DPF application. The effects of B100, PPO and the DPF on the biological test results vary strongly from positive to negative depending on the biological end point. The oxidative potential, measured via the DTT assay, of the B100 and PPO or DPF emissions is reduced by 95%. The cytotoxicity is increased for B100 by 200%. The measured mutagenicity, using the Ames assay test with TA98 and YG1024 strains of Salmonella typhimurium indicate a dose response for the nitroarene sensitive YG1024 strain for B100 and PPO (fold induction: 1.6). In summary B100 and PPO have good potential for the use as a second generation biofuel resulting in lower PM mass, similar to application of a DPF, but caution should be made due to potential increased toxicity. Besides regulation via mass, the biological reactivity of exhaust emissions of new (bio)fuels and application of new technologies, needs attention. The different responses of different biological tests as well as differences in results between test laboratories underline the need for harmonization of test methods and international cooperation.

  3. Mechanical characterization of a customized decellularized scaffold for vascular tissue engineering.

    Science.gov (United States)

    Sheridan, W S; Duffy, G P; Murphy, B P

    2012-04-01

    Several challenges persist when attempting to utilize decellularized tissue as a scaffold for vascular tissue engineering. Namely: poor cell infiltration/migration, excessive culture times associated with repopulating the scaffolds, and the achievement of a quiescent medial layer. In an attempt to create an optimum vascular scaffold, we customized the properties of decellularized porcine carotid arteries by: (i) creating cavities within the medial layer to allow direct injection of cells, and (ii) controlling the amount of collagen digestion to increase the porosity. Histological examination of our customized scaffold revealed a highly porous tissue structure containing consistent medial cavities running longitudinally through the porous scaffold wall. Mechanical testing of the customized scaffold showed that our minimal localized disruption to the ECM does not have a detrimental effect on the bulk mechanical response of the tissue. The results demonstrate that an increased stiffness and reduced distensibility occurs after decellularization when compared to the native tissue, however post scaffold customization we can revert the scaffold tensile properties back to that of the native tissue. This most noteworthy result occurs in the elastin dominant phase of the tensile response of the scaffold, indicating that no disruption has occurred to the elastin network by our decellularization and customization techniques. Additionally, the bulk seeding potential of the customized scaffold was demonstrated by direct injection of human smooth muscle cells through the medial cavities. The optimum cell dispersion was observed in the highest porosity scaffold, with large cell numbers retained within the medial layer after 24 h static culture. In summary, this study presents a novel customized decellularized vascular scaffold that has the capability of bulk seeding the media, and in tandem to this method, the porosity of the scaffold has been increased without compromising the

  4. Preparation and Characterization of Collagen-GAGs Bioactive Matrices for Tissue Engineering

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Collagen materials were crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) in the presence of chondroitin sulfate (CS), one of glycosaminoglycans (GAGs). PVA and chitosan were also blended with collagen. The physical and chemical properties of the matrices were characterized by SEM, DSC, and ESCA. L929 cells were implanted on the matrices to show the cytotoxic and the biological characters of the materials. The results indicate that EDC is an effective and non-cytotoxic cross-link reagent, which can replace the common dialdehyde reagent. The attachment of CS can improve the stability of collagen and accelerate cell growth.The addition of PVA can prepare porous matrices with smaller bore size. There are reactions between the chitosan and collagen, and the composite has good biological character. The presence of chitosan can also increase the amount of incorporated CS.

  5. Synthesis and Characterization of Nanodiamond Reinforced Chitosan for Bone Tissue Engineering

    Science.gov (United States)

    Sun, Yu; Yang, Qiaoqin; Wang, Haidong

    2016-01-01

    Multifunctional tissue scaffold material nanodiamond (ND)/chitosan (CS) composites with different diamond concentrations from 1 wt % to 5 wt % were synthesized through a solution casting method. The microstructure and mechanical properties of the composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and nanoindentation. Compared with pristine CS, the addition of ND resulted in a significant improvement of mechanical properties, including a 239%, 276%, 321%, 333%, and 343% increase in Young’s modulus and a 68%, 96%, 114%, 118%, and 127% increase in hardness when the ND amount was 1 wt %, 2 wt %, 3 wt %, 4 wt %, and 5 wt %, respectively. The strong interaction between ND surface groups and the chitosan matrix plays an important role in improving mechanical properties. PMID:27649252

  6. Engineering and characterization of mesoporous silica-coated magnetic particles for mercury removal from industrial effluents

    Science.gov (United States)

    Dong, Jie; Xu, Zhenghe; Wang, Feng

    2008-03-01

    Mesoporous silica coatings were synthesized on dense liquid silica-coated magnetite particles using cetyl-trimethyl-ammonium chloride (CTAC) as molecular templates, followed by sol-gel process. A specific surface area of the synthesized particles as high as 150 m 2/g was obtained. After functionalization with mercapto-propyl-trimethoxy-silane (MPTS) through silanation reaction, the particles exhibited high affinity of mercury in aqueous solutions. Atomic force microscopy (AFM), zeta potential measurement, thermal gravimetric analysis (TGA), analytical transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and atomic absorption spectroscopy (AAS) were used to characterize the synthesis processes, surface functionalization, and mercury adsorption on the synthesized magnetite particles. The loading capacity of the particles for mercury was determined to be as high as 14 mg/g at pH 2. A unique feature of strong magnetism of the synthesized nanocomposite particles makes the subsequent separation of the magnetic sorbents from complex multiphase suspensions convenient and effective.

  7. Estimation of Membrane Hydration Status for Standby Proton Exchange Membrane Fuel Cell Systems by Impedance Measurement: First Results on Stack Characterization

    DEFF Research Database (Denmark)

    Bidoggia, Benoit; Kær, Søren Knudsen

    Fuel cells have started replacing traditional lead-acid battery banks in backup systems. Although these systems are characterized by long periods of standby, they must be able to start at any instant in the shortest time. In the case of low temperature proton exchange membrane fuel cell systems......, a precise estimation of hydration status of the fuel cell during standby is important for a fast and safe startup. In this article, the measurement of the complex impedance of the fuel cell is suggested as a method to estimate the membrane hydration status. A 56-cell fuel cell stack has been symmetrically...... was applied, and the relationship between module of impedance and relative humidity was found. The results showed that measuring the impedance of a fuel cell during standby can be a viable way for estimating the hydration status of its membrane....

  8. Use of a Ni60Ti shape memory alloy for active jet engine chevron application: I. Thermomechanical characterization

    Science.gov (United States)

    Hartl, D. J.; Lagoudas, D. C.; Calkins, F. T.; Mabe, J. H.

    2010-01-01

    A shape memory alloy (SMA) with a composition of Ni60Ti40 (wt%) was chosen for the fabrication of active beam elements intended for use as cyclic actuators and incorporated into a morphing aerospace structure. The active structure is a variable-geometry chevron (VGC) designed to reduce jet engine noise in the take-off flight regime while maintaining efficiency in the cruise regime. This two-part work addresses the training, characterization and derived material properties of the new nickel-rich composition, the assessment of the actuation properties of the active beam actuator and the accurate analysis of the VGC and its subcomponents using a model calibrated from the material characterization. The characterization performed in part I of this work was intended to provide quantitative information used to predict the response of SMA beam actuators of the same composition and with the same heat treatment history. Material in the form of plates was received and ASTM standard tensile testing coupons were fabricated and tested. To fully characterize the material response as an actuator, various thermomechanical experiments were performed. Properties such as actuation strain and transformation temperatures as a function of applied stress were of primary interest. Results from differential scanning calorimetry, monotonic tensile loading and constant stress thermal loading for the as-received, untrained material are first presented. These show lower transformation temperatures, higher elastic stiffnesses (60-90 GPa) and lower recoverable transformation strains (≈1.5%) when compared to equiatomic NiTi (Nitinol). Stabilization (training) cycles were applied to the tensile specimens and characterization tests were repeated for the stable (trained) material. The effects of specimen training included the saturation of cyclically generated irrecoverable plastic strains and a broadening of the thermal transformation hysteresis. A set of final derived material properties for this

  9. Characterization and mapping of very fine particles in an engine machining and assembly facility.

    Science.gov (United States)

    Heitbrink, William A; Evans, Douglas E; Peters, Thomas M; Slavin, Thomas J

    2007-05-01

    Very fine particle number and mass concentrations were mapped in an engine machining and assembly facility in the winter and summer. A condensation particle counter (CPC) was used to measure particle number concentrations in the 0.01 microm to 1 microm range, and an optical particle counter (OPC) was used to measure particle number concentrations in 15 channels between 0.3 microm and 20 microm. The OPC measurements were used to estimate the respirable mass concentration. Very fine particle number concentrations were estimated by subtracting the OPC particle number concentrations from 0.3 microm to 1 microm from the CPC number concentrations. At specific locations during the summer visit, an electrical low pressure impactor was used to measure particle size distribution from 0.07 microm to 10 microm in 12 channels. The geometric mean ratio of respirable mass concentration estimated from the OPC to the gravimetrically measured mass concentration was 0.66 with a geometric standard deviation of 1.5. Very fine particle number concentrations in winter were substantially greater where direct-fire natural gas heaters were operated (7.5 x 10(5) particles/cm(3)) than where steam was used for heat (3 x 10(5) particles/cm(3)). During summer when heaters were off, the very fine particle number concentrations were below 10(5) particles/cm(3), regardless of location. Elevated very fine particle number concentrations were associated with machining operations with poor enclosures. Whereas respirable mass concentrations did not vary noticeably with season, they were greater in areas with poorly fitting enclosures (0.12 mg/m(3)) than in areas where state-of-the-art enclosures were used (0.03 mg/m(3)). These differences were attributed to metalworking fluid mist that escaped from poorly fitting enclosures. Particles generated from direct-fire natural gas heater operation were very small, with a number size distribution modal diameter of less than 0.023 microm. Aerosols generated by

  10. Engineering Science, Skills, and Bildung

    DEFF Research Database (Denmark)

    Christensen, Jens

    The background for the book is a quest for a thorough analysis of engineering, engineering science, and engineering education. Focusing on the concepts of engineering science, skills, and Bildung, the book investigates the real challenges that are confronting engineering today, and discusses how...... to respond to these. Thereby, the book offers a complex and nuanced basis for debates on the actual status and the future directions of engineering science, engineering education, and the everyday practice of engineers....

  11. Fabrication and characterization of electrospun osteon mimicking scaffolds for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Andric, T. [Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Sampson, A.C. [Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Freeman, J.W., E-mail: jwfreeman@vt.edu [Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States)

    2011-01-01

    Skeletal loss and bone deficiencies are a major worldwide problem with over 600,000 procedures performed in the US alone annually, making bone one of the most transplanted tissues, second to blood only. Bone is a composite tissue composed of organic matrix, inorganic bone mineral, and water. Structurally bone is organized into two distinct types: trabecular (or cancellous) and cortical (or compact) bones. Trabecular bone is characterized by an extensive interconnected network of pores. Cortical bone is composed of tightly packed units, called osteons, oriented parallel along to the axis of the bone. While the majority of scaffolds attempt to replicate the structure of the trabecular bone, fewer attempts have been made to create scaffolds to mimic the structure of cortical bone. The aim of this study was to develop a technique to fabricate scaffolds that mimic the organization of an osteon, the structural unit of cortical bone. We successfully built a rotating stage for PGA fibers and utilized it for collecting electrospun nanofibers and creating scaffolds. Resulting scaffolds consisted of concentric layers of electrospun PLLA or gelatin/PLLA nanofibers wrapped around PGA microfiber core with diameters that ranged from 200 to 600 {mu}m. Scaffolds were mineralized by incubation in 10x simulated body fluid, and scaffolds composed of 10%gelatin/PLLA had significantly higher amounts of calcium phosphate. The electrospun scaffolds also supported cellular attachment and proliferation of MC3T3 cells over the period of 28 days.

  12. Characterization of slow-gelling alginate hydrogels for intervertebral disc tissue-engineering applications.

    Science.gov (United States)

    Growney Kalaf, Emily A; Flores, Reynaldo; Bledsoe, J Gary; Sell, Scott A

    2016-06-01

    Reversal of intervertebral disc degeneration can have a potentially monumental effect on spinal health. As such, the goal of this research is to create an injectable, cellularized alginate-based nucleus pulposus that will restore disc function; with the primary goal of creating an alginate gel with tailorable rates of gelation to improve functionality over standard CaCl2 crosslinking techniques. Gelation characteristics of 1% sodium alginate were analyzed over various molar concentrations of a 1:2 ratio of CaCO3:glucono-δ-lactone (GDL), with 10% CaCl2 as the control crosslinker. Alginate construct characterization for all concentrations was performed via ultimate and cyclic compressive testing over a 28day degradation period in PBS. Dehydration, swell testing, and albumin release kinetics were determined, and cytotoxicity and cell homogeneity tests showed promise for cellularization strategies. Overall, the 30 and 60mM GDL alginate concentrations presented the most viable option for use in further studies, with a gelation time between 10 and 30min, low hysteresis over control, low percent change in thickness and weight under both PBS degradation and swelling conditions, and stable mechanical properties over 28days in vitro.

  13. Reaction engineering of co-condensing (methyl)ethoxysilane mixtures: Kinetic characterization and modeling

    Energy Technology Data Exchange (ETDEWEB)

    RANKIN,STEPHEN E.; MCCORMICK,ALON V.

    2000-01-26

    Molecular homogeneity frequently plays a decisive role in the effective application of organically modified silicate copolymers. However, methods of directly characterizing copolymerization extent in siloxanes generated from mixed alkoxysilanes are not always available or convenient. The authors present an alternative tool for determining kinetic parameters for models of alkoxysilane hydrolytic copolycondensation. Rather than restricting attention to single step batch reactors, they use a semibatch reactor with varying time of injection of one component. They describe the fitting method and show that all necessary kinetic parameters can be determined from a series of ordinary {sup 29}Si NMR data in a straightforward case study: copolymerization of dimethyldiethoxy silane and trimethylethoxysilane. Under conditions providing no direct {sup 29}Si NMR signature of copolymerization, they find kinetic trends consistent with those previously reported. As further validation, the results of a new series of experiments (varying the ratio of mono-functional to difunctional monomer) are predicted by the semibatch copolymerization model and measured parameters. Based on these results, they are able to calculate the molecular homogeneity in the copolymer products investigated. Even for this relatively simple system, the optimal injection time is a complex function of residence time, but early injection of the faster-condensing monomer gives the best homogeneity at long residence times.

  14. Engineering and Characterization of Collagen Networks Using Wet Atomic Force Microscopy and Environmental Scanning Electron Microscopy

    Science.gov (United States)

    Osborn, Jenna; Coffey, Tonya; Conrad, Brad; Burris, Jennifer; Hester, Brooke

    2014-03-01

    Collagen is an abundant protein and its monomers covalently crosslink to form fibrils which form fibers which contribute to forming macrostructures like tendon or bone. While the contribution is well understood at the macroscopic level, it is not well known at the fibril level. We wish to study the mechanical properties of collagen for networks of collagen fibers that vary in size and density. We present here a method to synthesize collagen networks from monomers and that allows us to vary the density of the networks. By using biotynilated collagen and a surface that is functionalized with avidin, we generate two-dimensional collagen networks across the surface of a silicon wafer. During network synthesis, the incubation time is varied from 30 minutes to 3 hours or temperature is varied from 25°C to 45°C. The two-dimensional collagen network created in the process is characterized using environmental atomic force microscopy (AFM) and scanning electron microscopy (SEM). The network density is measured by the number of strands in one frame using SPIP software. We expect that at body temperature (37°C) and with longer incubation times, the network density should increase.

  15. C-terminal engineering of CXCL12 and CCL5 chemokines: functional characterization by electrophysiological recordings.

    Directory of Open Access Journals (Sweden)

    Antoine Picciocchi

    Full Text Available Chemokines are chemotactic cytokines comprised of 70-100 amino acids. The chemokines CXCL12 and CCL5 are the endogenous ligands of the CXCR4 and CCR5 G protein-coupled receptors that are also HIV co-receptors. Biochemical, structural and functional studies of receptors are ligand-consuming and the cost of commercial chemokines hinders their use in such studies. Here, we describe methods for the expression, refolding, purification, and functional characterization of CXCL12 and CCL5 constructs incorporating C-terminal epitope tags. The model tags used were hexahistidines and Strep-Tag for affinity purification, and the double lanthanoid binding tag for fluorescence imaging and crystal structure resolution. The ability of modified and purified chemokines to bind and activate CXCR4 and CCR5 receptors was tested in Xenopus oocytes expressing the receptors, together with a Kir3 G-protein activated K(+ channel that served as a reporter of receptor activation. Results demonstrate that tags greatly influence the biochemical properties of the recombinant chemokines. Besides, despite the absence of any evidence for CXCL12 or CCL5 C-terminus involvement in receptor binding and activation, we demonstrated unpredictable effects of tag insertion on the ligand apparent affinity and efficacy or on the ligand dissociation. These tagged chemokines should constitute useful tools for the selective purification of properly-folded chemokines receptors and the study of their native quaternary structures.

  16. Nanoscopic and redox characterization of engineered horse cytochrome C chemisorbed on a bare gold electrode.

    Science.gov (United States)

    Andolfi, Laura; Caroppi, Paola; Bizzarri, Anna Rita; Piro, Maria Cristina; Sinibaldi, Federica; Ferri, Tommaso; Polticelli, Fabio; Cannistraro, Salvatore; Santucci, Roberto

    2007-06-01

    In this paper, we exploit the potential offered by site-directed mutagenesis to achieve direct adsorption of horse cyt c on a bare gold electrode surface. To this issue, the side chain T102 has been replaced by a cysteine. T102 is close to the surface exposed C-terminal residue (E104), therefore the T102C mutation is expected to generate an exposed cysteine side chain able to facilitate protein binding to the electrode via the sulphur atom (analogously to what observed for yeast iso-1-cyt c). Scanning Tunnelling and Tapping Mode Atomic Force Microscopy measurements show that the T102C mutant stably adsorbs on an Au(111) surface and retains the morphological characteristics of the native form. Cyclic voltammetry reveals that the adsorbed variant is electroactive; however, the heterogeneous electron transfer with the electrode surface is slower than that observed for yeast iso-1-cyt c. We ascribe it to differences in the tertiary architecture of the two proteins, characterized by different flexibility and stability. In particular, the region where the N- and C-terminal helices get in contact (and where the mutation occurs) is analyzed in detail, since the interactions between these two helices are considered crucial for the stability of the overall protein fold.

  17. Fabrication and characterization of gels with integrated channels using 3D printing with microfluidic nozzle for tissue engineering applications.

    Science.gov (United States)

    Attalla, R; Ling, C; Selvaganapathy, P

    2016-02-01

    The lack of a simple and effective method to integrate vascular network with engineered scaffolds and tissue constructs remains one of the biggest challenges in true 3D tissue engineering. Here, we detail the use of a commercially available, low-cost, open-source 3D printer modified with a microfluidic print-head in order to develop a method for the generation of instantly perfusable vascular network integrated with gel scaffolds seeded with cells. The print-head features an integrated coaxial nozzle that allows the fabrication of hollow, calcium-polymerized alginate tubes that can be easily patterned using 3D printing techniques. The diameter of the hollow channel can be precisely controlled and varied between 500 μm - 2 mm by changing applied flow rates or print-head speed. These channels are integrated into gel layers with a thickness of 800 μm - 2.5 mm. The structural rigidity of these constructs allows the fabrication of multi-layered structures without causing the collapse of hollow channels in lower layers. The 3D printing method was fully characterized at a range of operating speeds (0-40 m/min) and corresponding flow rates (1-30 mL/min) were identified to produce precise definition. This microfluidic design also allows the incorporation of a wide range of scaffold materials as well as biological constituents such as cells, growth factors, and ECM material. Media perfusion of the channels causes a significant viability increase in the bulk of cell-laden structures over the long-term. With this setup, gel constructs with embedded arrays of hollow channels can be created and used as a potential substitute for blood vessel networks.

  18. Fabrication and characterization of PCL/gelatin composite nanofibrous scaffold for tissue engineering applications by electrospinning method

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, Sneh [Department of Polymer and Process Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 (India); Dinda, Amit Kumar [Department of Pathology, All India Institute of Medical Science, New Delhi, 110029 (India); Mishra, Narayan Chandra, E-mail: mishrawise@googlemail.com [Department of Polymer and Process Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 (India)

    2013-04-01

    In the present study, composite nanofibrous tissue engineering-scaffold consisting of polycaprolactone and gelatin, was fabricated by electrospinning method, using a new cost-effective solvent mixture: chloroform/methanol for polycaprolactone (PCL) and acetic acid for gelatin. The morphology of the nanofibrous scaffold was investigated by using field emission scanning electron microscopy (FE-SEM) which clearly indicates that the morphology of nanofibers was influenced by the weight ratio of PCL to gelatin in the solution. Uniform fibers were produced only when the weight ratio of PCL/gelatin is sufficiently high (10:1). The scaffold was further characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis, and X-ray diffraction (XRD). FT-IR and TG analysis indicated some interactions between PCL and gelatin molecules within the scaffold, while XRD results demonstrated crystalline nature of PCL/gelatin composite scaffold. Cytotoxicity effect of scaffold on L929 mouse fibroblast cells was evaluated by MTT assay and cell proliferation on the scaffold was confirmed by DNA quantification. Positive results of MTT assay and DNA quantification L929 mouse fibroblast cells indicated that the scaffold made from the combination of natural polymer (gelatin) and synthetic polymer (PCL) may serve as a good candidate for tissue engineering applications. - Highlights: ► PCL/Gelatin scaffold was successfully fabricated by electrospinning method. ► PCL in CHCl{sub 3}/CH{sub 3}OH and gelatin in acetic acid: a novel polymer-solvent system. ► The morphology of nanofibers was influenced by the weight ratio of PCL/gelatin. ► Chemical interactions between PCL and gelatin molecules enhanced cell growth. ► Cell culture studies indicate the suitability of scaffold for tissue regeneration.

  19. Engineering salidroside biosynthetic pathway in hairy root cultures of Rhodiola crenulata based on metabolic characterization of tyrosine decarboxylase.

    Science.gov (United States)

    Lan, Xiaozhong; Chang, Kai; Zeng, Lingjiang; Liu, Xiaoqiang; Qiu, Fei; Zheng, Weilie; Quan, Hong; Liao, Zhihua; Chen, Min; Huang, Wenlin; Liu, Wanhong; Wang, Qiang

    2013-01-01

    Tyrosine decarboxylase initializes salidroside biosynthesis. Metabolic characterization of tyrosine decarboxylase gene from Rhodiola crenulata (RcTYDC) revealed that it played an important role in salidroside biosynthesis. Recombinant 53 kDa RcTYDC converted tyrosine into tyramine. RcTYDC gene expression was induced coordinately with the expression of RcUDPGT (the last gene involved in salidroside biosynthesis) in SA/MeJA treatment; the expression of RcTYDC and RcUDPGT was dramatically upregulated by SA, respectively 49 folds and 36 folds compared with control. MeJA also significantly increased the expression of RcTYDC and RcUDPGT in hairy root cultures. The tissue profile of RcTYDC and RcUDPGT was highly similar: highest expression levels found in stems, higher expression levels in leaves than in flowers and roots. The gene expressing levels were consistent with the salidroside accumulation levels. This strongly suggested that RcTYDC played an important role in salidroside biosynthesis in R. crenulata. Finally, RcTYDC was used to engineering salidroside biosynthetic pathway in R. crenulata hairy roots via metabolic engineering strategy of overexpression. All the transgenic lines showed much higher expression levels of RcTYDC than non-transgenic one. The transgenic lines produced tyramine, tyrosol and salidroside at higher levels, which were respectively 3.21-6.84, 1.50-2.19 and 1.27-3.47 folds compared with the corresponding compound in non-transgenic lines. In conclusion, RcTYDC overexpression promoted tyramine biosynthesis that facilitated more metabolic flux flowing toward the downstream pathway and as a result, the intermediate tyrosol was accumulated more that led to the increased production of the end-product salidroside.

  20. Engineering salidroside biosynthetic pathway in hairy root cultures of Rhodiola crenulata based on metabolic characterization of tyrosine decarboxylase.

    Directory of Open Access Journals (Sweden)

    Xiaozhong Lan

    Full Text Available Tyrosine decarboxylase initializes salidroside biosynthesis. Metabolic characterization of tyrosine decarboxylase gene from Rhodiola crenulata (RcTYDC revealed that it played an important role in salidroside biosynthesis. Recombinant 53 kDa RcTYDC converted tyrosine into tyramine. RcTYDC gene expression was induced coordinately with the expression of RcUDPGT (the last gene involved in salidroside biosynthesis in SA/MeJA treatment; the expression of RcTYDC and RcUDPGT was dramatically upregulated by SA, respectively 49 folds and 36 folds compared with control. MeJA also significantly increased the expression of RcTYDC and RcUDPGT in hairy root cultures. The tissue profile of RcTYDC and RcUDPGT was highly similar: highest expression levels found in stems, higher expression levels in leaves than in flowers and roots. The gene expressing levels were consistent with the salidroside accumulation levels. This strongly suggested that RcTYDC played an important role in salidroside biosynthesis in R. crenulata. Finally, RcTYDC was used to engineering salidroside biosynthetic pathway in R. crenulata hairy roots via metabolic engineering strategy of overexpression. All the transgenic lines showed much higher expression levels of RcTYDC than non-transgenic one. The transgenic lines produced tyramine, tyrosol and salidroside at higher levels, which were respectively 3.21-6.84, 1.50-2.19 and 1.27-3.47 folds compared with the corresponding compound in non-transgenic lines. In conclusion, RcTYDC overexpression promoted tyramine biosynthesis that facilitated more metabolic flux flowing toward the downstream pathway and as a result, the intermediate tyrosol was accumulated more that led to the increased production of the end-product salidroside.

  1. Characterizing Impacts and Implications of Proposals for Solar Radiation Management, a Form of Climate Engineering

    Science.gov (United States)

    Ricke, Katharine L.

    different ways. Hence the use of SRM to stabilize climate in all regions simultaneously may not be possible. Regional diversity in the response to different levels of SRM could complicate what is already a very challenging problem of global governance, and could make consensus about the "optimal" level of geo-engineering difficult, if not impossible, to achieve. The second experiment modeled SRM using a perturbed physics ensemble with a wide range of temperature responses and climate sensitivities, all of which are consistent with observed recent warming. The analysis shows that the efficacy and distribution of effects of SRM varies with the temperature response of the model. Models that produce more global warming are also generally more sensitive to SRM, so the amount of modification of the Earth's energy balance needed to meet any given climate stabilization criteria appear to be relatively insensitive to climate sensitivity. While in the more sensitive models, SRM is generally less successful in returning regional climates to their unperturbed states the longer it is used to compensate for rising greenhouse gases, it is also where SRM is most effective relative to a no SRM alternative. SRM does not prevent further acidification of the oceans and this fact, coupled with the fact that SRM can only slow, never halt, changes to regional climate states, makes SRM untenable as a long-term solution to the problems caused by rising GHGs in the atmosphere. Much more research on SRM is needed before any conclusions on whether or not to deploy it are reached, but this work suggests that regional inequities in climate response are probably not the main impediment to its effective implementation. While SRM can never perfectly correct for regional climate change, these experiments suggest that it generally reduces (rather than exacerbates) changes to regional temperature and precipitation and greatly reduces the rate of temperature change. Considering the slow progress society has

  2. Production, Characterization and Potential Uses of a 3D Tissue-engineered Human Esophageal Mucosal Model.

    Science.gov (United States)

    Green, Nicola H; Corfe, Bernard M; Bury, Jonathan P; MacNeil, Sheila

    2015-05-18

    The incidence of both esophageal adenocarcinoma and its precursor, Barrett's Metaplasia, are rising rapidly in the western world. Furthermore esophageal adenocarcinoma generally has a poor prognosis, with little improvement in survival rates in recent years. These are difficult conditions to study and there has been a lack of suitable experimental platforms to investigate disorders of the esophageal mucosa. A model of the human esophageal mucosa has been developed in the MacNeil laboratory which, unlike conventional 2D cell culture systems, recapitulates the cell-cell and cell-matrix interactions present in vivo and produces a mature, stratified epithelium similar to that of the normal human esophagus. Briefly, the model utilizes non-transformed normal primary human esophageal fibroblasts and epithelial cells grown within a porcine-derived acellular esophageal scaffold. Immunohistochemical characterization of this model by CK4, CK14, Ki67 and involucrin staining demonstrates appropriate recapitulation of the histology of the normal human esophageal mucosa. This model provides a robust, biologically relevant experimental model of the human esophageal mucosa. It can easily be manipulated to investigate a number of research questions including the effectiveness of pharmacological agents and the impact of exposure to environmental factors such as alcohol, toxins, high temperature or gastro-esophageal refluxate components. The model also facilitates extended culture periods not achievable with conventional 2D cell culture, enabling, inter alia, the study of the impact of repeated exposure of a mature epithelium to the agent of interest for up to 20 days. Furthermore, a variety of cell lines, such as those derived from esophageal tumors or Barrett's Metaplasia, can be incorporated into the model to investigate processes such as tumor invasion and drug responsiveness in a more biologically relevant environment.

  3. Report on Status of Shipment of High Fluence Austenitic Steel Samples for Characterization and Stress Corrosion Crack Testing

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Scarlett R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    The goal of the Mechanisms of Irradiation Assisted Stress Corrosion Cracking (IASCC) task in the LWRS Program is to conduct experimental research into understanding how multiple variables influence the crack initiation and crack growth in materials subjected to stress under corrosive conditions. This includes understanding the influences of alloy composition, radiation condition, water chemistry and metallurgical starting condition (i.e., previous cold work or heat treatments and the resulting microstructure) has on the behavior of materials. Testing involves crack initiation and growth testing on irradiated specimens of single-variable alloys in simulated Light Water Reactor (LWR) environments, tensile testing, hardness testing, microstructural and microchemical analysis, and detailed efforts to characterize localized deformation. Combined, these single-variable experiments will provide mechanistic understanding that can be used to identify key operational variables to mitigate or control IASCC, optimize inspection and maintenance schedules to the most susceptible materials/locations, and, in the long-term, design IASCC-resistant materials. In support of this research, efforts are currently underway to arrange shipment of “free” high fluence austenitic alloys available through Électricité de France (EDF) for post irradiation testing at the Oak Ridge National Laboratory (ORNL) and IASCC testing at the University of Michigan. These high fluence materials range in damage values from 45 to 125 displacements per atom (dpa). The samples identified for transport to the United States, which include nine, no-cost, 304, 308 and 316 tensile bars, were relocated from the Research Institute of Atomic Reactors (RIAR) in Dimitrovgrad, Ulyanovsk Oblast, Russia, and received at the Halden Reactor in Halden, Norway, on August 23, 2016. ORNL has been notified that a significant amount of work is required to prepare the samples for further shipment to Oak Ridge, Tennessee. The

  4. Characterizing Strain Variation in Engineered E. coli Using a Multi-Omics-Based Workflow

    DEFF Research Database (Denmark)

    Brunk, Elizabeth; George, Kevin W.; Alonso-Gutierrez, Jorge

    2016-01-01

    to pathway engineering; and demonstrates how biological mechanisms underlying strain variation can be exploited as an engineering strategy to increase product yield. As a proof of concept, we present the analysis of eight engineered strains producing three biofuels: isopentenol, limonene, and bisabolene......Python notebooks....

  5. Integrated, multidisciplinary reservoir characterization, modeling and engineering leading to enhanced oil recovery from the Midway-Sunset field, California

    Energy Technology Data Exchange (ETDEWEB)

    Schamel, S.; Forster, C.; Deo, M. (Univ. of Utah, Salt Lake City, UT (United States)) (and others)

    1996-01-01

    The Pru Fee property is developed in a heavy oil, Class III (slope and basin clastic sand), reservoir of the Midway-Sunset field, San Joaquin Basin, California. Wells on the property were shut-in with an estimated 85% of the original oil remaining in place because the reservoir failed to respond to conventional cyclic steaming. Producibility problems are attributed to the close proximity of the property to the margin of the field. Specific problems include complex reservoir geometry, thinning pay, bottom water, and dipping beds. These problems are likely common at the margins of the Midway-Sunset and other Class III reservoirs. This project forms the first step in returning the property to production and explores strategies that might be applied elsewhere. Reservoir characterization, modeling, and engineering methods are integrated to design, simulate, and implement a pilot steam flood. A new drillhole provides good quality, core through the pay zone and a full suite of geophysical logs. Correlations between geological and petrophysical data are used to extrapolate reservoir conditions from older logs and yield a 3-dimensional petrophysical model. Numerical results illustrate how each producibility problem might influence production and provide a framework for designing the pilot steam flood. This first phase illustrates how a multidisciplinary team can use established technologies in developing the detailed petrophysical, geological, and numerical models needed to enhance oil recovery from marginal areas of Class III reservoirs.

  6. Integrated, multidisciplinary reservoir characterization, modeling and engineering leading to enhanced oil recovery from the Midway-Sunset field, California

    Energy Technology Data Exchange (ETDEWEB)

    Schamel, S.; Forster, C.; Deo, M. [Univ. of Utah, Salt Lake City, UT (United States)] [and others

    1996-12-31

    The Pru Fee property is developed in a heavy oil, Class III (slope and basin clastic sand), reservoir of the Midway-Sunset field, San Joaquin Basin, California. Wells on the property were shut-in with an estimated 85% of the original oil remaining in place because the reservoir failed to respond to conventional cyclic steaming. Producibility problems are attributed to the close proximity of the property to the margin of the field. Specific problems include complex reservoir geometry, thinning pay, bottom water, and dipping beds. These problems are likely common at the margins of the Midway-Sunset and other Class III reservoirs. This project forms the first step in returning the property to production and explores strategies that might be applied elsewhere. Reservoir characterization, modeling, and engineering methods are integrated to design, simulate, and implement a pilot steam flood. A new drillhole provides good quality, core through the pay zone and a full suite of geophysical logs. Correlations between geological and petrophysical data are used to extrapolate reservoir conditions from older logs and yield a 3-dimensional petrophysical model. Numerical results illustrate how each producibility problem might influence production and provide a framework for designing the pilot steam flood. This first phase illustrates how a multidisciplinary team can use established technologies in developing the detailed petrophysical, geological, and numerical models needed to enhance oil recovery from marginal areas of Class III reservoirs.

  7. Application of simple biomechanical and biochemical tests to heart valve leaflets: implications for heart valve characterization and tissue engineering.

    Science.gov (United States)

    Huang, Hsiao-Ying S; Balhouse, Brittany N; Huang, Siyao

    2012-11-01

    A simple biomechanical test with real-time displacement and strain mapping is reported, which provides displacement vectors and principal strain directions during the mechanical characterization of heart valve tissues. The maps reported in the current study allow us to quickly identify the approximate strain imposed on a location in the samples. The biomechanical results show that the aortic valves exhibit stronger anisotropic mechanical behavior than that of the pulmonary valves before 18% strain equibiaxial stretching. In contrast, the pulmonary valves exhibit stronger anisotropic mechanical behavior than aortic valves beyond 28% strain equibiaxial stretching. Simple biochemical tests are also conducted. Collagens are extracted at different time points (24, 48, 72, and 120 h) at different locations in the samples. The results show that extraction time plays an important role in determining collagen concentration, in which a minimum of 72 h of extraction is required to obtain saturated collagen concentration. This work provides an easy approach for quantifying biomechanical and biochemical properties of semilunar heart valve tissues, and potentially facilitates the development of tissue engineered heart valves.

  8. Facile synthesis, characterization, and antimicrobial activity of cellulose-chitosan-hydroxyapatite composite material: a potential material for bone tissue engineering.

    Science.gov (United States)

    Mututuvari, Tamutsiwa M; Harkins, April L; Tran, Chieu D

    2013-11-01

    Hydroxyapatite (HAp) is often used as a bone-implant material because it is biocompatible and osteoconductive. However, HAp possesses poor rheological properties and it is inactive against disease-causing microbes. To improve these properties, we developed a green method to synthesize multifunctional composites containing: (1) cellulose (CEL) to impart mechanical strength; (2) chitosan (CS) to induce antibacterial activity thereby maintaining a microbe-free wound site; and (3) HAp. In this method, CS and CEL were co-dissolved in an ionic liquid (IL) and then regenerated from water. HAp was subsequently formed in situ by alternately soaking [CEL+CS] composites in aqueous solutions of CaCl2 and Na2 HPO4 . At least 88% of IL used was recovered for reuse by distilling the aqueous washings of [CEL+CS]. The composites were characterized using FTIR, XRD, and SEM. These composites retained the desirable properties of their constituents. For example, the tensile strength of the composites was enhanced 1.9 times by increasing CEL loading from 20% to 80%. Incorporating CS in the composites resulted in composites which inhibited the growth of both Gram positive (MRSA, S. aureus and VRE) and Gram negative (E. coli and P. aeruginosa) bacteria. These findings highlight the potential use of [CEL+CS+HAp] composites as scaffolds in bone tissue engineering.

  9. PEGylation and pharmacological characterization of a potential anti-tumor drug, an engineered arginine deiminase originated from Pseudomonas plecoglossicida.

    Science.gov (United States)

    Zhang, Long; Liu, Menghan; Jamil, Serwanja; Han, Ruizhi; Xu, Guochao; Ni, Ye

    2015-02-01

    Arginine deiminase (ADI) has been studied as a potential anti-cancer agent for arginine-auxotrophic tumors. PEGylation is one of the best methods to formulate a bioconjugated protein with extended physical stability and reduced immunogenicity. Here, PEGylation and pharmacological properties of an engineered ADI originated from Pseudomonas plecoglossicida were studied. Among polyethylene glycol (PEG) reagents with succinimidyl ester groups varying in size and linkers, three PEGylated products with high yield and catalytic activity were further characterized, named ADI-SS(20 kDa), ADI-SC(20 kDa), and ADI-SPA(20 kDa). In the pharmacodynamic/pharmacokinetic (PD/PK) studies with ADI-SPA(20 kDa), a remarkable improvement in circulating half-life compared with native ADI was observed. ADI-SPA(20 kDa) injections via intravenous, intramuscular and subcutaneous routes all exhibited superior efficacy than native ADI on depleting serum arginine. Additionally, our results demonstrated that single ADI-SPA(20 kDa) administration of 5 U/mouse via intravenous injection could maintain serum arginine at an undetectable level for 5 days with a half-life of 53.2 h, representing 11-fold improvement in half-life than that of the native ADI. In a mice H22 hepatocarcinoma model, ADI-SPA(20 kDa) dosage of 5 U per 5 days showed an inhibition rate of 95.02% on tumor growth during 15-day treatments.

  10. Processing and characterization of diatom nanoparticles and microparticles as potential source of silicon for bone tissue engineering.

    Science.gov (United States)

    Le, Thi Duy Hanh; Bonani, Walter; Speranza, Giorgio; Sglavo, Vincenzo; Ceccato, Riccardo; Maniglio, Devid; Motta, Antonella; Migliaresi, Claudio

    2016-02-01

    Silicon plays an important role in bone formation and maintenance, improving osteoblast cell function and inducing mineralization. Often, bone deformation and long bone abnormalities have been associated with silica/silicon deficiency. Diatomite, a natural deposit of diatom skeleton, is a cheap and abundant source of biogenic silica. The aim of the present study is to validate the potential of diatom particles derived from diatom skeletons as silicon-donor materials for bone tissue engineering applications. Raw diatomite (RD) and calcined diatomite (CD) powders were purified by acid treatments, and diatom microparticles (MPs) and nanoparticles (NPs) were produced by fragmentation of purified diatoms under alkaline conditions. The influence of processing on the surface chemical composition of purified diatomites was evaluated by X-ray photoelectron spectroscopy (XPS). Diatoms NPs were also characterized in terms of morphology and size distribution by transmission electron microscopy (TEM) and Dynamic light scattering (DLS), while diatom MPs morphology was analyzed by scanning electron microscopy (SEM). Surface area and microporosity of the diatom particles were evaluated by nitrogen physisorption methods. Release of silicon ions from diatom-derived particles was demonstrated using inductively coupled plasma optical emission spectrometry (ICP/OES); furthermore, silicon release kinetic was found to be influenced by diatomite purification method and particle size. Diatom-derived microparticles (MPs) and nanoparticles (NPs) showed limited or no cytotoxic effect in vitro depending on the administration conditions.

  11. Synthesis and characterization of porous biphasic calcium phosphate scaffold from different porogens for possible bone tissue engineering applications

    Directory of Open Access Journals (Sweden)

    Amera A.

    2011-01-01

    Full Text Available By using the wet precipitation method, Biphasic calcium phosphate granules were synthesized with Ca/P ratio1.52 and controlled porosity, pore size distribution, and granule size. Microporosity was then obtained by adjusting sintering temperature while macroporosity was prepared by adding 1:3 wt% ratio of two normally used porogens (naphthalene and sugar and 2 newly introduced porogens (sago and lentil. Samples from each ratio were pressed into pellets and were fired at 500ºC for 2 hours with 0.5°C/minute heating rate (for removal of porogens and further sintered at 850°C for 2 hours with 5°C/minute before cooling down to room temperature. The granules were prepared by crushing and sieving BCP sintered pellets to get granules of sizes ranging from 250-500μm. X-rays diffraction (XRD, field emission scanning electron microscope (FESEM, particle size and porosity analyses were employed in order to characterize the granules. A round to oval shape pores with 200-400 μm size were obtained and identical to the prepared porogens’ particle size. This approach gives the desirable properties near to normal bone leading to a perfect osteogenesis for the purpose tissue engineering.

  12. Synthesis, characterization and antioxidant activity of a novel electroactive and biodegradable polyurethane for cardiac tissue engineering application.

    Science.gov (United States)

    Baheiraei, Nafiseh; Yeganeh, Hamid; Ai, Jafar; Gharibi, Reza; Azami, Mahmoud; Faghihi, Faezeh

    2014-11-01

    There has been a growing trend towards applying conducting polymers for electrically excitable cells to increase electrical signal propagation within the cell-loaded substrates. A novel biodegradable electroactive polyurethane containing aniline pentamer (AP-PU) was synthesized and fully characterized by spectroscopic methods. To tune the physico-chemical properties and biocompatibility, the AP-PU was blended with polycaprolactone (PCL). The presence of electroactive moieties and the electroactivity behavior of the prepared films were confirmed by UV-visible spectroscopy and cyclic voltammetry. A conventional four probe analysis demonstrated the electrical conductivity of the films in the semiconductor range (~10(-5)S/cm). MTT assays using L929 mouse fibroblast and human umbilical vein endothelial cells (HUVECs) showed that the prepared blend (PB) displayed more cytocompatibility compared with AP-PU due to the introduction of a biocompatible PCL moiety. The in vitro cell culture also confirmed that PB was as supportive as tissue culture plate. The antioxidant activity of the AP-PU was proved using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay by employing UV-vis spectroscopy. In vitro degradation tests conducted in phosphate-buffered saline, pH7.4 and pH5.5, proved that the films were also biodegradable. The results of this study have highlighted the potential application of this bioelectroactive polyurethane as a platform substrate to study the effect of electrical signals on cell activities and to direct desirable cell function for tissue engineering applications.

  13. Software engineering education in medical informatics.

    Science.gov (United States)

    Leven, F J

    1989-11-01

    Requirements and approaches of Software Engineering education in the field of Medical Informatics are described with respect to the impact of (1) experiences characterizing the "software misery", (2) status and tendencies in software methodology, and (3) educational status and needs in computer science education influenced by the controversy "theoretical versus practical education". Special attention is directed toward the growing importance of analysis, design methods, and techniques in the professional spectrum of Medical Informatics, the relevance of general principles of systems engineering in health care, the potential of non-procedural programming paradigms, and the intersection of Artificial Intelligence and education. Realizations of and experiences with programs in the field of Software Engineering are reported with respect to special requirements in Medical Informatics.

  14. Mod II engine development

    Science.gov (United States)

    Karl, David W.

    1987-01-01

    The Mod II engine, a four-cylinder, automotive Stirling engine utilizing the Siemens-Rinia double-acting concept, was assembled and became operational in January 1986. This paper describes the Mod II engine, its first assembly, and the subsequent development work done on engine components up to the point that engine performance characterization testing took place. Performance data for the engine are included.

  15. Method development for the characterization of transport processes of engineered nanoparticles in saturated soils with focus on silver nanoparticles

    OpenAIRE

    Braun, Anika

    2015-01-01

    With the growing amount of production and application of engineered nanoparticles, concerns are raising regarding the fate of the potentially toxic materials in the environment. In order to assess the potential of engineered nanoparticles for migration in soils and aquifers, an experimental study and subsequent mathematical modeling were carried out with the objective of the qualitative and quantitative description of the transport and deposition processes of engineered nanoparticles in water...

  16. Research Status on Application of Phosphogypsum in Road Engineering%磷石膏在道路工程应用的研究现状

    Institute of Scientific and Technical Information of China (English)

    谭明洋; 相利学; 李国龙

    2016-01-01

    磷石膏的堆存问题由来已久,至今仍未得到有效利用,将磷石膏用于道路工程建设中不仅可以消耗大量磷石膏,而且能够降低道路建设成本,同时缓解了环境压力。磷石膏在道路工程中应用的研究主要包括在路面基层材料中的应用和道路沥青中的应用两个方面。概述了磷石膏在道路工程中应用的研究现状,认为磷石膏在路面基层材料和沥青中应用的理论研究尚不足,此外,应充分考虑磷石膏的添加对路面基层材料和道路沥青各方面的影响,不能顾此失彼。%Phosphogypsum stacking problem has existed for a long time, and it has not yet been used up effectively. Phosphogypsum for road construction can consume a large amount of phosphogypsum, and reduce the cost of road construction, at the same time, ease the environmental pressure. The application of phosphogypsum in road base materials and road asphalt are the main aspects in road engineering. The research status of the application of phosphogypsum in road base material and road asphalt was summarized, it proposed that theoretical research was still insufficient, in addition, all the effects on performances should be considered when phosphogypsum was used in road construction.

  17. Preparation and characterization of multi-layer biodegradable nanofibers by coaxial electrospinning and their potential for tissue engineering

    Science.gov (United States)

    Liu, Wenwen

    As an evolution of conventional electrospinning, coaxial electrospinning became popular soon after its debut as a novel way to develop nanofibers with special structures, such as core-shell and hollow interior. In recent years, there has been an increasing interest in a modified coaxial electrospinning, tri-layer coaxial electrospinning, to develop more complex structures, such as multi-layer and nanowire-in-microtube. Previous studies have primarily concentrated on the fabrication of tri-layered inorganic fibers while studies on tri-layered coaxial polymeric fibers has not been reported until very recently. Our research focuses on the fabrication of core-shell and tri-layer structured biodegradable polymeric nanofibers with coaxial electrospinning. Different characterization methods have been applied to observe the internal structure in single nanofibers and the potential application of tri-layer coaxial electrospinning has been discussed. The material system consists of biodegradable natural polymer gelatin, synthetic polymers poly (epsilon-caprolactone) (PCL) and poly (lactic-co-glycolic acid) (PLGA). A uniquely designed three-needle concentric spinneret is developed to perform tri-layer coaxial electrospinning. Different kinds of core-shell structured nanofibers, including gelatin/PCL, PCL/gelatin, gelatin/PLGA and PCL/PLGA, have been fabricated with a customized coaxial electrospinning apparatus. Two kinds of tri-layer coaxial nanofibers, two-component ABA structured gelatin/PCL/gelatin biodegradable nanofibers and tri-component ABC structured gelatin/PCL/PLGA biodegradable nanofibers, have been developed with the customized three needle coaxial electrospinning setup. The core-shell and tri-layered structures of electrospun nanofibers have been characterized by several commonly used techniques, such as laser scanning confocal microscopy (LSCM) and transmission electron microscopy (TEM). Besides the conventional methods, other newer techniques, including

  18. Processing and characterization of diatom nanoparticles and microparticles as potential source of silicon for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Le, Thi Duy Hanh [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Bonani, Walter [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy); Speranza, Giorgio [Center for Materials and Microsystems, PAM-SE, Fondazione Bruno Kessler, Trento (Italy); Sglavo, Vincenzo; Ceccato, Riccardo [Department of Industrial Engineering, University of Trento, Trento (Italy); Maniglio, Devid; Motta, Antonella [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy); Migliaresi, Claudio, E-mail: claudio.migliaresi@unitn.it [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy)

    2016-02-01

    Silicon plays an important role in bone formation and maintenance, improving osteoblast cell function and inducing mineralization. Often, bone deformation and long bone abnormalities have been associated with silica/silicon deficiency. Diatomite, a natural deposit of diatom skeleton, is a cheap and abundant source of biogenic silica. The aim of the present study is to validate the potential of diatom particles derived from diatom skeletons as silicon-donor materials for bone tissue engineering applications. Raw diatomite (RD) and calcined diatomite (CD) powders were purified by acid treatments, and diatom microparticles (MPs) and nanoparticles (NPs) were produced by fragmentation of purified diatoms under alkaline conditions. The influence of processing on the surface chemical composition of purified diatomites was evaluated by X-ray photoelectron spectroscopy (XPS). Diatoms NPs were also characterized in terms of morphology and size distribution by transmission electron microscopy (TEM) and Dynamic light scattering (DLS), while diatom MPs morphology was analyzed by scanning electron microscopy (SEM). Surface area and microporosity of the diatom particles were evaluated by nitrogen physisorption methods. Release of silicon ions from diatom-derived particles was demonstrated using inductively coupled plasma optical emission spectrometry (ICP/OES); furthermore, silicon release kinetic was found to be influenced by diatomite purification method and particle size. Diatom-derived microparticles (MPs) and nanoparticles (NPs) showed limited or no cytotoxic effect in vitro depending on the administration conditions. - Highlights: • Diatomite is a natural source of silica and has a potential as silicon-donor for bone regenerative applications. • Diatom particles derived from purified diatom skeletons were prepared by fragmentation under extreme alkaline condition. • Dissolution of diatom particles derived from diatom skeletons in DI water depend on purification method

  19. Synthesis, characterization and antioxidant activity of a novel electroactive and biodegradable polyurethane for cardiac tissue engineering application

    Energy Technology Data Exchange (ETDEWEB)

    Baheiraei, Nafiseh [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 1417755469 Tehran (Iran, Islamic Republic of); Yeganeh, Hamid, E-mail: h.yeganeh@ippi.ac.ir [Department of Polyurethane, Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran (Iran, Islamic Republic of); Ai, Jafar [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 1417755469 Tehran (Iran, Islamic Republic of); Brain and Spinal Injury Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Gharibi, Reza [Department of Polyurethane, Iran Polymer and Petrochemical Institute, P.O. Box: 14965/115, Tehran (Iran, Islamic Republic of); Azami, Mahmoud; Faghihi, Faezeh [Department of Tissue Engineering, School of Advanced Medical Technologies, Tehran University of Medical Sciences, 1417755469 Tehran (Iran, Islamic Republic of)

    2014-11-01

    There has been a growing trend towards applying conducting polymers for electrically excitable cells to increase electrical signal propagation within the cell-loaded substrates. A novel biodegradable electroactive polyurethane containing aniline pentamer (AP-PU) was synthesized and fully characterized by spectroscopic methods. To tune the physico-chemical properties and biocompatibility, the AP-PU was blended with polycaprolactone (PCL). The presence of electroactive moieties and the electroactivity behavior of the prepared films were confirmed by UV–visible spectroscopy and cyclic voltammetry. A conventional four probe analysis demonstrated the electrical conductivity of the films in the semiconductor range (∼ 10{sup −5} S/cm). MTT assays using L929 mouse fibroblast and human umbilical vein endothelial cells (HUVECs) showed that the prepared blend (PB) displayed more cytocompatibility compared with AP-PU due to the introduction of a biocompatible PCL moiety. The in vitro cell culture also confirmed that PB was as supportive as tissue culture plate. The antioxidant activity of the AP-PU was proved using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay by employing UV–vis spectroscopy. In vitro degradation tests conducted in phosphate-buffered saline, pH 7.4 and pH 5.5, proved that the films were also biodegradable. The results of this study have highlighted the potential application of this bioelectroactive polyurethane as a platform substrate to study the effect of electrical signals on cell activities and to direct desirable cell function for tissue engineering applications. - Highlights: • Straight forward methodology for synthesis of electroactive polyurethane • Biodegradability and non-toxicity through proper selection of starting materials • Supporting cell proliferation and attachment combined with antioxidant property.

  20. Screening-engineered Field-effect Photovoltaics and Synthesis, Characterization, and Applications of Carbon-based and Related Nanomaterials

    Science.gov (United States)

    Regan, William Raymond

    Carbon nanomaterials, and especially graphene (a 2D carbon allotrope), possess unique electronic, optical, and mechanical properties and allow access to both new physical phenomena and reinventions of familiar technologies. In the first part of this thesis (chapter 2), the low carrier density and high conductivity of graphene are used to repurpose the electric field effect (used for many decades in transistors) into a universally-applicable doping method for electrically-contacted semiconductors. This method, referred to as "screening-engineered field-effect photovoltaics" as the electric field doping is enabled by a carefully-designed poorly-screening electrode (e.g. graphene), is shown to open up many new low-cost and abundant semiconductors for use in high efficiency solar cells. We extend this method beyond ultrathin materials such as graphene and show that 1D nanowire electrodes made of any material also allow penetration of applied electric fields. The next part of this thesis (chapter 3) focuses on the fundamental properties of graphene -- its structure, synthesis, characterization, and manipulation -- and on using graphene as a building block for other nanostructures: grafold, graphene sandwiches and veils, and graphritos. In chapter 4, various graphene electronics are constructed and tested. Graphene field-effect transistors (FETs) and p-n junctions are fabricated to study the influence of the substrate on graphene carrier mobility and doping. Graphene nanoribbons and grafold FETs are made to investigate the effects of additional confinement on electronic transport. Chapter 5 summarizes synthesis methods and additional experiments with other nanomaterials, including dichalcogenides and chalcogenides (magnesium diboride, gallium selenide, and tin sulfide), carbon nanomaterials (carbon nanotubes and graphene), and copper oxide. Additional measurement and fabrication methods are discussed in appendix A.

  1. Construction and characterization of a tissue-engineered oral mucosa equivalent based on a chitosan-fish scale collagen composite.

    Science.gov (United States)

    Terada, Michiko; Izumi, Kenji; Ohnuki, Hisashi; Saito, Taro; Kato, Hiroko; Yamamoto, Marie; Kawano, Yoshiro; Nozawa-Inoue, Kayoko; Kashiwazaki, Haruhiko; Ikoma, Toshiyuki; Tanaka, Junzo; Maeda, Takeyasu

    2012-10-01

    This study was designed to (1) assess the in vitro biocompatibility of a chitosan-collagen composite scaffold (C3) constructed by blending commercial chitosan and tilapia scale collagen with oral mucosa keratinocytes, (2) histologically and immunohistochemically characterize an ex vivo-produced oral mucosa equivalent constructed using the C3 (EVPOME-C), and (3) compare EVPOME-C with oral mucosa constructs utilizing AlloDerm® (EVPOME-A), BioMend® Extend™ (EVPOME-B), and native oral mucosa. C3 scaffold had a well-developed fibril network and a sufficiently small porosity to prevent keratinocytes from growing inside the scaffold after cell-seeding. The EVPOME oral mucosa constructs were fabricated in a chemically defined culture system. After culture at an air-liquid interface, EVPOME-C and EVPOME-B had multilayered epithelium with keratinization, while EVPOME-A had a more organized stratified epithelium. Ki-67 and p63 immunolabeled cells in the basal layer of all EVPOMEs suggested a regenerative ability. Compared with native oral mucosa, the keratin 15 and 10/13 expression patterns in all EVPOMEs showed a less-organized differentiation pattern. In contrast to the β1-integrin and laminin distribution in EVPOME-A and native oral mucosa, the subcellular deposition in EVPOME-C and EVPOME-B indicated that complete basement membrane formation failed. These findings demonstrated that C3 has a potential application for epithelial tissue engineering and provides a new potential therapeutic device for oral mucosa regenerative medicine.

  2. Estimation of Membrane Hydration Status for Standby Proton Exchange Membrane Fuel Cell Systems by Impedance Measurement: First Results on Stack Characterization

    DEFF Research Database (Denmark)

    Bidoggia, Benoit; Kær, Søren Knudsen

    Fuel cells have started replacing traditional lead-acid battery banks in backup systems. Although these systems are characterized by long periods of standby, they must be able to start at any instant in the shortest time. In the case of low temperature proton exchange membrane fuel cell systems...... was applied, and the relationship between module of impedance and relative humidity was found. The results showed that measuring the impedance of a fuel cell during standby can be a viable way for estimating the hydration status of its membrane....

  3. A methodology of characterizing status and trend of land changes in oases: a case study of Sangong River watershed, Xinjiang, China.

    Science.gov (United States)

    Luo, G P; Zhou, C H; Chen, X; Li, Y

    2008-09-01

    Land change is often studied with Markov models to develop a probability transition matrix. The existing methods dependent on such matrixes cannot effectively characterize some important aspects associated with land change such as status, direction, trend and regional variations. This study presents mathematical models to quantify these elements, defining unbalanced, quasi-balanced and balanced status, one- and two-way transitions and the rising or falling trends. Using these models and remote-sensing imageries, the landscape was studied for a case area, the oasis of Sangong River in Xinjiang, Northwest China where typical arid conditions prevail. Land expansion and contraction among various land types and for the entire oasis were analyzed for the periods of 1978-1987, 1978-1998 and 1987-1998. The changes were closely related to a strong economic growth after the land-reform campaign and adoption of the market economy in China in the 1980s to early 1990s, a process not strictly Markovian that requires stationarity and randomness. Information on land-change status and trend is important for a better understanding of the underlying driving processes but also for land-use planning and decision-making.

  4. Fabrication and characterization of a rapid prototyped tissue engineering scaffold with embedded multicomponent matrix for controlled drug release

    DEFF Research Database (Denmark)

    Chen, Muwan; Le, Dang Q S; Hein, San

    2012-01-01

    Bone tissue engineering implants with sustained local drug delivery provide an opportunity for better postoperative care for bone tumor patients because these implants offer sustained drug release at the tumor site and reduce systemic side effects. A rapid prototyped macroporous polycaprolactone......, this scaffold can fulfill the requirements for both bone tissue engineering and local sustained release of an anticancer drug in vitro. These results suggest that the scaffold can be used clinically in reconstructive surgery after bone tumor resection. Moreover, by changing the composition and amount...... of individual components, the scaffold can find application in other tissue engineering areas that need local sustained release of drug....

  5. Preparation and characterization of oxidized alginate covalently cross-linked galactosylated chitosan scaffold for liver tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Chen Feng [College of Polymer Science and Engineering, Sichuan University, Chengdu, Sichuan 610065 (China); Suzhou Institute of Sichuan University, Suzhou 215123 (China); Tian Meng; Zhang Dongming; Wang Jianyun; Wang Qiguang [College of Polymer Science and Engineering, Sichuan University, Chengdu, Sichuan 610065 (China); Yu Xixun [College of Polymer Science and Engineering, Sichuan University, Chengdu, Sichuan 610065 (China); Suzhou Institute of Sichuan University, Suzhou 215123 (China); Zhang Xiaohua [College of Polymer Science and Engineering, Sichuan University, Chengdu, Sichuan 610065 (China); Wan Changxiu, E-mail: wanchangxiu@163.com [College of Polymer Science and Engineering, Sichuan University, Chengdu, Sichuan 610065 (China)

    2012-02-01

    Liver tissue engineering (LTE) requires a perfect extracellular matrix (ECM) for hepatocytes culture to maintain high level of liver-specific functions. Here, we reported a LTE scaffold derived from oxidized alginate covalently cross-linked galactosylated chitosan via Schiff base reaction, without employing any extraneous chemical cross-linking agent. The structure of galactosylated chitosan (GC) and oxidized alginate was confirmed by Fourier transformed infrared (FTIR) spectra, proton nuclear magnetic resonance ({sup 1}H-NMR) spectroscopy, X-ray diffraction (XRD) or thermogravimetric (TG) analysis. The structure and properties of a series of the scaffolds were characterized by FTIR, XRD, scanning electron microscopy (SEM), porosity, equilibrium swelling, mechanical properties, thermal stability and in vitro degradation. FTIR spectra confirmed the characteristic peak of Schiff base groups in the scaffolds and XRD indicated the scaffolds could be amorphous. SEM analysis showed that the scaffolds displayed highly porous surfaces with average pore size of 50-150 {mu}m and interconnected pore structure in the internal structure with average pore size of 100-250 {mu}m. Porosity measurement suggested the scaffolds had a porosity of about 70%. The compressive modulus of the scaffolds (hydrated) was in the range of 4.2-6.3 kPa. Further studies showed that, with the increase of the oxidized alginate content, the equilibrium swelling and in vitro degradation rate of the scaffolds decreased and the thermal stability slightly increased, which might mainly attribute to the difference of the degree of cross-linking and the nature properties of the raw materials. Additionally, the biocompatibility of the scaffolds was evaluated in vitro. The results showed that the hepatocytes cultured on the scaffolds had a typical spheroidal morphology, formed multi-cellular aggregates and presented perfect integration with the scaffolds, which suggested that the scaffolds may be potential

  6. Kinematic Stirling Engine Performance

    Science.gov (United States)

    Tew, J. R. C.

    1986-01-01

    Computer program developed for analyzing thermodynamic characteristics of kinematic Stirling engine. Computes time-varying piston positions, pressures, and gas temperatures in each of gas-control volumes into which engine working space is divided. Engine performance characterized by calculations of power and efficiency (both indicated and brake). Inputs to code are engine geometrical parameter, engine-operating conditions, and indexes that specify various options available.

  7. Characterization of diesel particles: effects of fuel reformulation, exhaust aftertreatment, and engine operation on particle carbon composition and volatility.

    Science.gov (United States)

    Alander, Timo J A; Leskinen, Ari P; Raunemaa, Taisto M; Rantanen, Leena

    2004-05-01

    Diesel exhaust particles are the major constituent of urban carbonaceous aerosol being linked to a large range of adverse environmental and health effects. In this work, the effects of fuel reformulation, oxidation catalyst, engine type, and engine operation parameters on diesel particle emission characteristics were investigated. Particle emissions from an indirect injection (IDI) and a direct injection (DI) engine car operating under steady-state conditions with a reformulated low-sulfur, low-aromatic fuel and a standard-grade fuel were analyzed. Organic (OC) and elemental (EC) carbon fractions of the particles were quantified by a thermal-optical transmission analysis method and particle size distributions measured with a scanning mobility particle sizer (SMPS). The particle volatility characteristics were studied with a configuration that consisted of a thermal desorption unit and an SMPS. In addition, the volatility of size-selected particles was determined with a tandem differential mobility analyzer technique. The reformulated fuel was found to produce 10-40% less particulate carbon mass compared to the standard fuel. On the basis of the carbon analysis, the organic carbon contributed 27-61% to the carbon mass of the IDI engine particle emissions, depending on the fuel and engine operation parameters. The fuel reformulation reduced the particulate organic carbon emissions by 10-55%. In the particles of the DI engine, the organic carbon contributed 14-26% to the total carbon emissions, the advanced engine technology, and the oxidation catalyst, thus reducing the OC/EC ratio of particles considerably. A relatively good consistency between the particulate organic fraction quantified with the thermal optical method and the volatile fraction measured with the thermal desorption unit and SMPS was found.

  8. Performance, Efficiency, and Emissions Characterization of Reciprocating Internal Combustion Engines Fueled with Hydrogen/Natural Gas Blends

    Energy Technology Data Exchange (ETDEWEB)

    Kirby S. Chapman; Amar Patil

    2007-06-30

    Hydrogen is an attractive fuel source not only because it is abundant and renewable but also because it produces almost zero regulated emissions. Internal combustion engines fueled by compressed natural gas (CNG) are operated throughout a variety of industries in a number of mobile and stationary applications. While CNG engines offer many advantages over conventional gasoline and diesel combustion engines, CNG engine performance can be substantially improved in the lean operating region. Lean operation has a number of benefits, the most notable of which is reduced emissions. However, the extremely low flame propagation velocities of CNG greatly restrict the lean operating limits of CNG engines. Hydrogen, however, has a high flame speed and a wide operating limit that extends into the lean region. The addition of hydrogen to a CNG engine makes it a viable and economical method to significantly extend the lean operating limit and thereby improve performance and reduce emissions. Drawbacks of hydrogen as a fuel source, however, include lower power density due to a lower heating value per unit volume as compared to CNG, and susceptibility to pre-ignition and engine knock due to wide flammability limits and low minimum ignition energy. Combining hydrogen with CNG, however, overcomes the drawbacks inherent in each fuel type. Objectives of the current study were to evaluate the feasibility of using blends of hydrogen and natural gas as a fuel for conventional natural gas engines. The experiment and data analysis included evaluation of engine performance, efficiency, and emissions along with detailed in-cylinder measurements of key physical parameters. This provided a detailed knowledge base of the impact of using hydrogen/natural gas blends. A four-stroke, 4.2 L, V-6 naturally aspirated natural gas engine coupled to an eddy current dynamometer was used to measure the impact of hydrogen/natural gas blends on performance, thermodynamic efficiency and exhaust gas emissions

  9. Commercial aircraft engine emissions characterization of in-use aircraft at Hartsfield-Jackson Atlanta International Airport.

    Science.gov (United States)

    Herndon, Scott C; Jayne, John T; Lobo, Prem; Onasch, Timothy B; Fleming, Gregg; Hagen, Donald E; Whitefield, Philip D; Miake-Lye, Richard C

    2008-03-15

    The emissions from in-use commercial aircraft engines have been analyzed for selected gas-phase species and particulate characteristics using continuous extractive sampling 1-2 min downwind from operational taxi- and runways at Hartsfield-Jackson Atlanta International Airport. Using the aircraft tail numbers, 376 plumes were associated with specific engine models. In general, for takeoff plumes, the measured NOx emission index is lower (approximately 18%) than that predicted by engine certification data corrected for ambient conditions. These results are an in-service observation of the practice of "reduced thrust takeoff". The CO emission index observed in ground idle plumes was greater (up to 100%) than predicted by engine certification data for the 7% thrust condition. Significant differences are observed in the emissions of black carbon and particle number among different engine models/technologies. The presence of a mode at approximately 65 nm (mobility diameter) associated with takeoff plumes and a smaller mode at approximately 25 nm associated with idle plumes has been observed. An anticorrelation between particle mass loading and particle number concentration is observed.

  10. Measurement and characterization of fully transient diesel fuel jet processes in an optical engine with production injectors

    Science.gov (United States)

    Neal, Nicholas; Rothamer, David

    2016-10-01

    The effects of transient rate-of-injection profiles on high-pressure diesel fuel jets have been studied in an optically accessible internal combustion engine. High-speed optical imaging measurements were applied over a range of ambient conditions, fuel types, and injection parameters. This paper demonstrates that during the early part of the injection, while the liquid core is disintegrating, the penetration is functionally linked to the inviscid orifice exit velocity up until a downstream distance hypothesized to be the jet breakup length. The jets then transitioned to a mixing dominated penetration behavior afterward. Therefore, for cases that exhibit transient rate-of-injection profiles, quasi-steady penetration analytical solutions for penetration have poor agreement with the empirical data. The development of an adaptive edgefinding algorithm for accurately detecting jets in engines is detailed. These findings indicate that empirical correlations widely used throughout the engine community for estimating jet penetration do not accurately represent actual injection parameters under transient conditions.

  11. Synthesis and characterization of electrospun polyvinyl alcohol nanofibrous scaffolds modified by blending with chitosan for neural tissue engineering

    Directory of Open Access Journals (Sweden)

    Naghavi Alhosseini S

    2012-01-01

    Full Text Available Sanaz Naghavi Alhosseini1, Fathollah Moztarzadeh1, Masoud Mozafari1, Shadnaz Asgari2, Masumeh Dodel3, Ali Samadikuchaksaraei4,5, Saeid Kargozar6, Newsha Jalali11Biomaterials Group, Faculty of Biomedical Engineering (Center of Excellence, Amirkabir University of Technology, Tehran, Iran; 2Neural Systems and Dynamics Laboratory, Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, CA, USA; 3Nanotechnology and Tissue Engineering Department, Stem Cell Technology Research Center, Tehran, Iran; 4Department of Biotechnology and Cellular and Molecular Research Center, Tehran University of Medical Sciences, Tehran, Iran; 5Biological Systems Engineering Laboratory, Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, London, UK; 6Department of Biotechnology, Tehran University of Medical Sciences, Tehran, IranAbstract: Among several attempts to integrate tissue engineering concepts into strategies to repair different parts of the human body, neuronal repair stands as a challenging area due to the complexity of the structure and function of the nervous system and the low efficiency of conventional repair approaches. Herein, electrospun polyvinyl alcohol (PVA/chitosan nanofibrous scaffolds have been synthesized with large pore sizes as potential matrices for nervous tissue engineering and repair. PVA fibers were modified through blending with chitosan and porosity of scaffolds was measured at various levels of their depth through an image analysis method. In addition, the structural, physicochemical, biodegradability, and swelling of the chitosan nanofibrous scaffolds were evaluated. The chitosan-containing scaffolds were used for in vitro cell culture in contact with PC12 nerve cells, and they were found to exhibit the most balanced properties to meet the basic required specifications for nerve cells. It could be concluded that addition of chitosan to the PVA

  12. 工民建工程施工管理的现状问题与对策%Analysis of the Status Problems and Countermeasures of Civil Engineering Construction Management

    Institute of Scientific and Technical Information of China (English)

    潘海滨

    2013-01-01

    笔者长期从事建筑工程现场施工管理工作,本文首先对我国目前工民建工程施工管理的现状进行了分析,并根据现状中存在的问题提出了相应的对策,以提高工程的施工管理质量。%In this article, the author engaged in site construct-ion management of engineering construction for a long time. This article first carries out the analysis of the status quo of Chinese current civil engineering construction management and put forward the corresponding countermeasures based on the problems in the current situation in order to improve the construction management quality of project.

  13. Science in Requirements Engineering

    National Research Council Canada - National Science Library

    Suhaimi Jaafar

    2014-01-01

    Based on a review of the articles about methodological principles, and some research classifications, in this work an overview of the nature and status of science in Requirements Engineering is done...

  14. Aircraft Emissions Characterization: TF41-A2, TF30-P103, and TF30-P109 Engines

    Science.gov (United States)

    1987-12-01

    heated (150oC) six-port valve ( Carle Instruments Model 5621) and onto the analytical column. The components in each trap were then flash-evaporated...TR-85-14, Air Force Engineering and Services Center, HQ AFESC/RWVS, Tyndall AFB, FL (1985). 8. Nebel , G. J., "Benzene in Auto Exhaust," J. Air Poll

  15. Characterization of emissions from commercial aircraft engines during the Aircraft Particle Emissions eXperiment (APEX) 1 to 3

    Science.gov (United States)

    The fine particulate matter emissions from aircraft operations at large airports located in areas of the U. S. designated as non-attainment for the National Ambient Air Quality Standard for PM-2.5 are of major environmental concern. PM emissions data for commercial aircraft engin...

  16. Development and characterization of a spheroidal coculture model of endothelial cells and fibroblasts for improving angiogenesis in tissue engineering

    DEFF Research Database (Denmark)

    Wenger, Andreas; Kowalewski, Nadja; Stahl, Andreas

    2005-01-01

    Neovascularization is a critical step in tissue engineering applications since implantation of voluminous grafts without sufficient vascularity results in hypoxic cell death of central tissues. We have developed a three-dimensional spheroidal coculture system consisting of human umbilical vein en...

  17. Report on Status of Shipment of High Fluence Austenitic Steel Samples for Characterization and Stress Corrosion Crack Testing

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Scarlett R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    The goal of the Mechanisms of Irradiation Assisted Stress Corrosion Cracking (IASCC) task in the LWRS Program is to conduct experimental research into understanding how multiple variables influence the crack initiation and crack growth in materials subjected to stress under corrosive conditions. This includes understanding the influences of alloy composition, radiation condition, water chemistry and metallurgical starting condition (i.e., previous cold work or heat treatments and the resulting microstructure) has on the behavior of materials. Testing involves crack initiation and growth testing on irradiated specimens of single-variable alloys in simulated Light Water Reactor (LWR) environments, tensile testing, hardness testing, microstructural and microchemical analysis, and detailed efforts to characterize localized deformation. Combined, these single-variable experiments will provide mechanistic understanding that can be used to identify key operational variables to mitigate or control IASCC, optimize inspection and maintenance schedules to the most susceptible materials/locations, and, in the long-term, design IASCC-resistant materials.

  18. Development, optimization and characterization of a full-thickness tissue engineered human oral mucosal model for biological assessment of dental biomaterials.

    Science.gov (United States)

    Moharamzadeh, K; Brook, I M; Van Noort, R; Scutt, A M; Smith, K G; Thornhill, M H

    2008-04-01

    Restorative dental materials and oral health care products come into direct contact with oral mucosa and can cause adverse reactions. In order to obtain an accurate risk assessment, the in vitro test model must reflect the clinical situation as closely as possible. The aim of this study was to develop and optimize a three-dimensional full-thickness engineered human oral mucosal model, which can be used for biological assessment of dental materials. In this study human oral fibroblasts and keratinocytes were isolated from patients and seeded onto a number of collagen-based and synthetic scaffolds using a variety of cell seeding techniques and grown at the air/liquid interface to construct human oral mucosa equivalents. Suitability of 10 different scaffolds for engineering human oral mucosa was evaluated in terms of biocompatibility, biostability, porosity, and the ability to mimic normal human oral mucosa morphology. Finally an optimized full-thickness engineered human oral mucosa was developed and characterized using transmission electron microscopy and immunostaining. The oral mucosa reconstruct resembled native human oral mucosa and it has the potential to be used as an accurate and reproducible test model in mucotoxicity and biocompatibility evaluation of dental materials.

  19. Space Shuttle Main Engine Low Pressure Oxidizer Turbo-Pump Inducer Dynamic Environment Characterization through Water Model and Hot-Fire Testing

    Science.gov (United States)

    Arellano, Patrick; Patton, Marc; Schwartz, Alan; Stanton, David

    2006-01-01

    The Low Pressure Oxidizer Turbopump (LPOTP) inducer on the Block II configuration Space Shuttle Main Engine (SSME) experienced blade leading edge ripples during hot firing. This undesirable condition led to a minor redesign of the inducer blades. This resulted in the need to evaluate the performance and the dynamic environment of the redesign, relative to the current configuration, as part of the design acceptance process. Sub-scale water model tests of the two inducer configurations were performed, with emphasis on the dynamic environment due to cavitation induced vibrations. Water model tests were performed over a wide range of inlet flow coefficient and pressure conditions, representative of the scaled operating envelope of the Block II SSME, both in flight and in ground hot-fire tests, including all power levels. The water test hardware, facility set-up, type and placement of instrumentation, the scope of the test program, specific test objectives, data evaluation process and water test results that characterize and compare the two SSME LPOTP inducers are discussed. In addition, dynamic characteristics of the two water models were compared to hot fire data from specially instrumented ground tests. In general, good agreement between the water model and hot fire data was found, which confirms the value of water model testing for dynamic characterization of rocket engine turbomachinery.

  20. Turbine Engine Research Center (TERC) Data System Enhancement and Test Article Evaluation. Delivery Order 0002: TERC Aeromechanical Characterization

    Science.gov (United States)

    2005-06-01

    problems associated with the design and operation of turbomachines becomes increasingly important as engineers strive to enhance their performance...frequency close to one of the natural frequencies since the blade-to-air density ratio of turbomachine blades is large, unlike aircraft wings. Flut- ter is...Greater control and understanding of flutter can significantly reduce cost in the design and development of turbomachines . Active flutter control

  1. Engineering and Functional Characterization of Fusion Genes Identifies Novel Oncogenic Drivers of Cancer. | Office of Cancer Genomics

    Science.gov (United States)

    Oncogenic gene fusions drive many human cancers, but tools to more quickly unravel their functional contributions are needed. Here we describe methodology permitting fusion gene construction for functional evaluation. Using this strategy, we engineered the known fusion oncogenes, BCR-ABL1, EML4-ALK, and ETV6-NTRK3, as well as 20 previously uncharacterized fusion genes identified in TCGA datasets.

  2. Characterization of particle size distribution from diesel engines fueled with palm-biodiesel blends and paraffinic fuel blends

    Science.gov (United States)

    Lin, Yuan-Chung; Lee, Chia-Fon; Fang, Tiegang

    Biodiesels are promoted as alternative fuels and their applications in diesel engines have been investigated by many researchers. However, the particle size distribution emitted from heavy-duty diesel engines fueled with palm-biodiesel blended with premium diesel fuel and paraffinic fuel blended with palm-biodiesel has seldom been addressed. Thus, five test fuels were used in this work to study the particle size distribution: D100 (premium diesel fuel), B100 (100% palm-biodiesel), B20 (20 vol% palm-biodiesel+80 vol% D100), BP9505 (95 vol% paraffinic fuel+5 vol% palm-biodiesel) and BP8020 (80 vol% paraffinic fuel+20 vol% palm-biodiesel). A Micro-Orifice Uniform Deposit Impactor (MOUDI) equipped with aluminum filters was used to collect size-resolved samples. Experimental results indicated that palm-biodiesel blends and paraffinic fuel blends could improve combustion efficiency in diesel engines, but pure palm-biodiesel could cause incomplete combustion. Adding palm-biodiesel to diesel fuel would slightly increase particles with diameter matter of BP9505 and BP8020 existed in coarse particles (diameter: 2.5-10 μm). Energy efficiency also increases significantly by 12.3-15.1% with the introduction of paraffinic fuel blends into the engine. Nevertheless, paraffinic fuel blends also reduce the emission of particulate matters by 36.0-38.4%. Carbon monoxide was decreased by 36.8-48.5%. Total hydrocarbon is 39.6-41.7% less than diesel fuel combustion. Nitrogen oxides emission is about 5% lower for paraffinic fuel. These results show that paraffinic fuel can be very competitive and replaced diesel fuels in the future.

  3. Fabrication and characterization of a rapid prototyped tissue engineering scaffold with embedded multicomponent matrix for controlled drug release

    Directory of Open Access Journals (Sweden)

    Chen M

    2012-08-01

    Full Text Available Muwan Chen,1,2 Dang QS Le,1,2 San Hein,2 Pengcheng Li,1 Jens V Nygaard,2 Moustapha Kassem,3 Jørgen Kjems,2 Flemming Besenbacher,2 Cody Bünger11Orthopaedic Research Lab, Aarhus University Hospital, Aarhus C, Denmark; 2Interdisciplinary Nanoscience Center (iNANO, Aarhus University, Aarhus C, Denmark; 3Department of Endocrinology and Metabolism, Odense University Hospital, Odense C, DenmarkAbstract: Bone tissue engineering implants with sustained local drug delivery provide an opportunity for better postoperative care for bone tumor patients because these implants offer sustained drug release at the tumor site and reduce systemic side effects. A rapid prototyped macroporous polycaprolactone scaffold was embedded with a porous matrix composed of chitosan, nanoclay, and β-tricalcium phosphate by freeze-drying. This composite scaffold was evaluated on its ability to deliver an anthracycline antibiotic and to promote formation of mineralized matrix in vitro. Scanning electronic microscopy, confocal imaging, and DNA quantification confirmed that immortalized human bone marrow-derived mesenchymal stem cells (hMSC-TERT cultured in the scaffold showed high cell viability and growth, and good cell infiltration to the pores of the scaffold. Alkaline phosphatase activity and osteocalcin staining showed that the scaffold was osteoinductive. The drug-release kinetics was investigated by loading doxorubicin into the scaffold. The scaffolds comprising nanoclay released up to 45% of the drug for up to 2 months, while the scaffold without nanoclay released 95% of the drug within 4 days. Therefore, this scaffold can fulfill the requirements for both bone tissue engineering and local sustained release of an anticancer drug in vitro. These results suggest that the scaffold can be used clinically in reconstructive surgery after bone tumor resection. Moreover, by changing the composition and amount of individual components, the scaffold can find application in other

  4. Local image variance of 7 Tesla SWI is a new technique for preoperative characterization of diffusely infiltrating gliomas: correlation with tumour grade and IDH1 mutational status

    Energy Technology Data Exchange (ETDEWEB)

    Grabner, Guenther [Medical University of Vienna, High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumours Unit (CCC-CNS), Vienna (Austria); Carinthia University of Applied Sciences, Department of Health Sciences and Social Work, Klagenfurt am Woerthersee (Austria); Kiesel, Barbara; Millesi, Matthias; Wurzer, Ayguel; Knosp, Engelbert; Wolfsberger, Stefan; Widhalm, Georg [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumours Unit (CCC-CNS), Vienna (Austria); Medical University of Vienna, Department of Neurosurgery, Vienna (Austria); Woehrer, Adelheid [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumours Unit (CCC-CNS), Vienna (Austria); Medical University of Vienna, Institute of Neurology, Vienna (Austria); Goed, Sabine [Medical University of Vienna, High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Mallouhi, Ammar [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumours Unit (CCC-CNS), Vienna (Austria); Medical University of Vienna, Department of Radiology, Vienna (Austria); Marosi, Christine; Preusser, Matthias [Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumours Unit (CCC-CNS), Vienna (Austria); Medical University of Vienna, Department of Internal Medicine I, Vienna (Austria); Trattnig, Siegfried [Medical University of Vienna, High Field Magnetic Resonance Centre, Department of Biomedical Imaging and Image-Guided Therapy, Vienna (Austria); Medical University of Vienna, Comprehensive Cancer Center, Central Nervous System Tumours Unit (CCC-CNS), Vienna (Austria)

    2017-04-15

    To investigate the value of local image variance (LIV) as a new technique for quantification of hypointense microvascular susceptibility-weighted imaging (SWI) structures at 7 Tesla for preoperative glioma characterization. Adult patients with neuroradiologically suspected diffusely infiltrating gliomas were prospectively recruited and 7 Tesla SWI was performed in addition to standard imaging. After tumour segmentation, quantification of intratumoural SWI hypointensities was conducted by the SWI-LIV technique. Following surgery, the histopathological tumour grade and isocitrate dehydrogenase 1 (IDH1)-R132H mutational status was determined and SWI-LIV values were compared between low-grade gliomas (LGG) and high-grade gliomas (HGG), IDH1-R132H negative and positive tumours, as well as gliomas with significant and non-significant contrast-enhancement (CE) on MRI. In 30 patients, 9 LGG and 21 HGG were diagnosed. The calculation of SWI-LIV values was feasible in all tumours. Significantly higher mean SWI-LIV values were found in HGG compared to LGG (92.7 versus 30.8; p < 0.0001), IDH1-R132H negative compared to IDH1-R132H positive gliomas (109.9 versus 38.3; p < 0.0001) and tumours with significant CE compared to non-significant CE (120.1 versus 39.0; p < 0.0001). Our data indicate that 7 Tesla SWI-LIV might improve preoperative characterization of diffusely infiltrating gliomas and thus optimize patient management by quantification of hypointense microvascular structures. (orig.)

  5. Engineered carbon (biochar) prepared by direct pyrolysis of Mg-accumulated tomato tissues: characterization and phosphate removal potential.

    Science.gov (United States)

    Yao, Ying; Gao, Bin; Chen, Jianjun; Zhang, Ming; Inyang, Mandu; Li, Yuncong; Alva, Ashok; Yang, Liuyan

    2013-06-01

    An innovative method was developed to produce engineered biochar from magnesium (Mg) enriched tomato tissues through slow pyrolysis in a N2 environment. Tomato plants treated with 25mM Mg accumulated much higher level of Mg in tissue, indicating Mg can be substantially enriched in tomato plants, and pyrolysis process further concentrated Mg in the engineered biochar (8.8% Mg). The resulting Mg-biochar composites (MgEC) showed better sorption ability to phosphate (P) in aqueous solutions compared to the other four tomato leaves biochars. Statistical analysis showed a strong and significant correlation between P removal rate and biochar Mg content (R(2)=0.78, and p<0.001), indicating the enriched Mg in the engineered biochar is the main factor controlling its P removal ability. SEM-EDX, XRD and XPS analyses showed that nanoscale Mg(OH)2 and MgO particles were presented on the surface of MgEC, which serve as the main adsorption sites for aqueous P.

  6. Design, analysis, and characterization of stress-engineered 3D microstructures comprised of PECVD silicon oxide and nitride

    Science.gov (United States)

    Pi, Chia-Hsing; Turner, Kevin T.

    2016-06-01

    Microelectromechanical systems (MEMS) are typically 2D or quasi-3D structures fabricated using surface and bulk micromachining processes. In this work, an approach for 3D structure fabrication based on stress engineering is demonstrated. Specifically, sub-mm 3D spherical cage-like structures are realized through the deformation of bilayers of residually-stressed silicon oxide and silicon nitride with micrometer-scale thicknesses. Analytical and finite models to predict the shape of stress-engineered structures based on geometry and residual stress are described and used for structure design. A systematic experimental study was performed to quantify residual stresses in silicon nitride films made by plasma-enhanced chemical vapor deposition (PECVD). The measurements show that the residual stress of PECVD silicon nitride can be tuned over a wide range of tensile stresses through the control of deposition parameters, such as flow rate and power. Stress engineered 3D cage-like structures comprised of PECVD silicon nitride and oxide films were fabricated. 3D structures with a range of curvatures were demonstrated. The measured geometry of the fabricated structures are in good agreement with predictions from analytical and finite element models.

  7. Engineering tribology

    CERN Document Server

    Stachowiak, Gwidon

    2013-01-01

    Engineering Tribology, 4th Edition is an established introductory reference focusing on the key concepts and engineering implications of tribology. Taking an interdisciplinary view, the book brings together the relevant knowledge from different fields needed to achieve effective analysis and control of friction and wear. Updated to cover recent advances in tribology, this new edition includes new sections on ionic and mesogenic lubricants, surface texturing, and multiscale characterization of 3D surfaces and coatings. Current trends in nanotribology are discussed, such as those relating to

  8. Development and Deployment of an Aerospace Recommended Practice (ARP) Compliant Measurement System for nvPM Certification Measurements of Aircraft Engines - Current Status.

    Science.gov (United States)

    Whitefield, P. D.; Hagen, D. E.; Lobo, P.; Miake-Lye, R. C.

    2015-12-01

    The Society of Automotive Engineers (SAE) Aircraft Exhaust Emissions Measurement Committee (E-31) has published an Aerospace Information Report (AIR) 6241 detailing the sampling system for the measurement of non-volatile particulate matter (nvPM) from aircraft engines (SAE 2013). The system is designed to operate in parallel with existing International Civil Aviation Organization (ICAO) Annex 16 compliant combustion gas sampling systems used for emissions certification from aircraft engines captured by conventional (Annex 16) gas sampling rakes (ICAO, 2008). The SAE E-31 committee is also working to ballot an Aerospace Recommended Practice (ARP) that will provide the methodology and system specification to measure nvPM from aircraft engines. The ARP is currently in preparation and is expected to be ready for ballot in 2015. A prototype AIR-compliant nvPM measurement system - The North American Reference System (NARS) has been built and evaluated at the MSTCOE under the joint sponsorship of the FAA, EPA and Transport Canada. It has been used to validate the performance characteristics of OEM AIR-compliant systems and is being used in engine certification type testing at OEM facilities to obtain data from a set of representative engines in the fleet. The data collected during these tests will be used by ICAO/CAEP/WG3/PMTG to develop a metric on which on the regulation for nvPM emissions will be based. This paper will review the salient features of the NARS including: (1) emissions sample transport from probe tip to the key diagnostic tools, (2) the mass and number-based diagnostic tools for nvPM mass and number concentration measurement and (3) methods employed to assess the extent of nvPM loss throughout the sampling system. This paper will conclude with a discussion of the recent results from inter-comparison studies conducted with other US - based systems that gives credence to the ARP's readiness for ballot.

  9. Genome scale engineering techniques for metabolic engineering.

    Science.gov (United States)

    Liu, Rongming; Bassalo, Marcelo C; Zeitoun, Ramsey I; Gill, Ryan T

    2015-11-01

    Metabolic engineering has expanded from a focus on designs requiring a small number of genetic modifications to increasingly complex designs driven by advances in genome-scale engineering technologies. Metabolic engineering has been generally defined by the use of iterative cycles of rational genome modifications, strain analysis and characterization, and a synthesis step that fuels additional hypothesis generation. This cycle mirrors the Design-Build-Test-Learn cycle followed throughout various engineering fields that has recently become a defining aspect of synthetic biology. This review will attempt to summarize recent genome-scale design, build, test, and learn technologies and relate their use to a range of metabolic engineering applications.

  10. Characterization of a newly established aggregation of the invasive ladybeetle Harmonia axyridis and current status of the invader in Spain

    Directory of Open Access Journals (Sweden)

    Xavier Pons

    2015-06-01

    Full Text Available The multicoloured Asian ladybeetle, Harmonia axyridis (Pallas, an invasive biocontrol agent introduced in North and South America, as well as in Europe for aphid control, drastically affected assemblages of native coccinellid species, local communities and people. Although the insect is common in several European countries and it was released in Spain for aphid control in 1995, no evidence of population establishment has been reported until 2011. In the present paper, 1 we summarize the records of the invasive ladybeetle in Spain and provide numerous new mentions, and 2 we follow for the first time an overwintering aggregation from autumn to spring and characterize some individual features which allow us to determine its phenology of the establishment and spreading. The results establish clearly that: 1 H. axyridis is (until now restricted to Catalonia (NE Spain but the invading process is in progress and the insect is able to occupy different habitats; 2 the ladybeetle overwinters successfully in Spain without significant natural mortality or parasitism; 3 the form succinea represents 73-81% of the overwintering individuals, and 4 the invasion takes probably its origin from Southern France. The potential impact of the invasion by H. axyridis in Spain is discussed.

  11. The status and characterization of Enteroramus dimorphus: a xylose-fermenting yeast attached to the gut of beetles.

    Science.gov (United States)

    Suh, Sung-Oui; White, Merlin M; Nguyen, Nhu H; Blackwell, Meredith

    2004-01-01

    Enteroramus dimorphus from the gut of the passalid beetle Odontotaenius disjunctus was described originally as a yeast-like fungus of unknown taxonomic affiliation. The fungus can be observed in situ, attached by a specialized cell to the beetle hindgut wall. In a recent study of yeast endosymbionts from a variety of beetles, we discovered that E. dimorphus is a member of the Pichia stipitis (Saccharomycetes) clade, known for xylose fermentation and assimilation. The closest relative of E. dimorphus is the PASS1 isolate, repeatedly acquired from passalid beetles in eastern North America from Pennsylvania to Louisiana. In addition to xylose fermentation and assimilation, these yeasts are characterized by the production of hat-shaped ascospores in culture, assimilation of a wide range of sugars, and synthesis of several vitamins. Enteroramus dimorphus, however, can be distinguished from close relatives by several physiological characteristics and rDNA sequences, which vary slightly from the more widespread PASS1 genotype. We present an amended description of E. dimorphus and discuss its symbiotic phase in association with O. disjunctus, including a holdfast that parallels those of unrelated symbiotic yeasts associated with nematodes.

  12. Characterization of a newly established aggregation of the invasive ladybeetle Harmonia axyridis and current status of the invader in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Pons, X.; Roca, M.; Lumbierres, B.; Lucas, E.

    2015-07-01

    The multicoloured Asian ladybeetle, Harmonia axyridis (Pallas), an invasive biocontrol agent introduced in North and South America, as well as in Europe for aphid control, drastically affected assemblages of native coccinellid species, local communities and people. Although the insect is common in several European countries and it was released in Spain for aphid control in 1995, no evidence of population establishment has been reported until 2011. In the present paper, 1) we summarize the records of the invasive ladybeetle in Spain and provide numerous new mentions, and 2) we follow for the first time an overwintering aggregation from autumn to spring and characterize some individual features which allow us to determine its phenology of the establishment and spreading. The results establish clearly that: 1) H. axyridis is (until now) restricted to Catalonia (NE Spain) but the invading process is in progress and the insect is able to occupy different habitats; 2) the ladybeetle overwinters successfully in Spain without significant natural mortality or parasitism; 3) the form succinea represents 73-81% of the overwintering individuals, and 4) the invasion takes probably its origin from Southern France. The potential impact of the invasion by H. axyridis in Spain is discussed. (Author)

  13. Local image variance of 7 Tesla SWI is a new technique for preoperative characterization of diffusely infiltrating gliomas: correlation with tumour grade and IDH1 mutational status.

    Science.gov (United States)

    Grabner, Günther; Kiesel, Barbara; Wöhrer, Adelheid; Millesi, Matthias; Wurzer, Aygül; Göd, Sabine; Mallouhi, Ammar; Knosp, Engelbert; Marosi, Christine; Trattnig, Siegfried; Wolfsberger, Stefan; Preusser, Matthias; Widhalm, Georg

    2017-04-01

    To investigate the value of local image variance (LIV) as a new technique for quantification of hypointense microvascular susceptibility-weighted imaging (SWI) structures at 7 Tesla for preoperative glioma characterization. Adult patients with neuroradiologically suspected diffusely infiltrating gliomas were prospectively recruited and 7 Tesla SWI was performed in addition to standard imaging. After tumour segmentation, quantification of intratumoural SWI hypointensities was conducted by the SWI-LIV technique. Following surgery, the histopathological tumour grade and isocitrate dehydrogenase 1 (IDH1)-R132H mutational status was determined and SWI-LIV values were compared between low-grade gliomas (LGG) and high-grade gliomas (HGG), IDH1-R132H negative and positive tumours, as well as gliomas with significant and non-significant contrast-enhancement (CE) on MRI. In 30 patients, 9 LGG and 21 HGG were diagnosed. The calculation of SWI-LIV values was feasible in all tumours. Significantly higher mean SWI-LIV values were found in HGG compared to LGG (92.7 versus 30.8; p Tesla SWI-LIV might improve preoperative characterization of diffusely infiltrating gliomas and thus optimize patient management by quantification of hypointense microvascular structures. • 7 Tesla local image variance helps to quantify hypointense susceptibility-weighted imaging structures. • SWI-LIV is significantly increased in high-grade and IDH1-R132H negative gliomas. • SWI-LIV is a promising technique for improved preoperative glioma characterization. • Preoperative management of diffusely infiltrating gliomas will be optimized.

  14. Development of rheological characterization and twin-screw extrusion/spiral winding processing methods for functionally-graded tissue engineering scaffolds and characterization of cell/biomaterial interactions

    Science.gov (United States)

    Ozkan, Seher

    Tissue engineering involves the fabrication of biodegradable scaffolds, on which various types of cells are grown, to provide tissue constructs for tissue repair/regeneration. Native tissues have complex structures, with functions and properties changing spatially and temporally, and require special tailoring of tissue engineering scaffolds to allow mimicking of their complex elegance. The understanding of the rheological behavior of the biodegradable polymer and the thermo-mechanical history that the polymer experiences during processing is critical in fabricating scaffolds with appropriate microstructural distributions. This study has first focused on the rheological material functions of various gel-like fluids including biofluids and hydrogels, which can emulate the viscoelastic behavior of biofluids. Viscoplasticity and wall slip were recognized as key attributes of such systems. Furthermore, a new technology base involving twin-screw extrusion/spiral winding (TSESW) process was developed for the shaping of functionally-graded scaffolds. This novel scaffold fabrication technology was applied to the development of polycaprolactone (PCL) scaffolds, incorporated with tricalcium phosphate nanoparticles and various porogens in graded fashion. The protein encapsulation and controlled release capabilities of the TSESW process was also demonstrated by dispersing bovine serum albumin (BSA) protein into the PCL matrix. Effects of processing conditions and porosity distributions on compressive properties, surface topography, encapsulation efficiency, release profiles and the secondary structure of BSA were investigated. The PCL scaffolds were determined to be biocompatible, with the proliferation rates of human fetal osteoblast cells (hFOB) increasing with increasing porosity and decreasing concentration of TCP. BSA proteins were determined to be denatured to a greater extent with melt extrusion in the 80-100°C range (in comparison to wet extrusion using organic

  15. Characterization of the Staphylococcal enterotoxin A: Vβ receptor interaction using human receptor fragments engineered for high affinity.

    Science.gov (United States)

    Sharma, P; Postel, S; Sundberg, E J; Kranz, D M

    2013-12-01

    Staphylococcal food poisoning is a gastrointestinal disorder caused by the consumption of food containing Staphylococcal enterotoxins. Staphylococcal enterotoxin A (SEA) is the most common enterotoxin recovered from food poisoning outbreaks in the USA. In addition to its enteric activity, SEA also acts as a potent superantigen through stimulation of T cells, although less is known about its interactions than the superantigens SEB, SEC and toxic shock syndrome toxin-1. To understand more about SEA:receptor interactions, and to develop toxin-detection systems for use in food testing, we engineered various SEA-binding receptor mutants. The extracellular domain of the receptor, a variable region of the beta chain (Vβ22) of the T-cell receptor, was engineered for stability as a soluble protein and for high affinity, using yeast-display technology. The highest affinity mutant was shown to bind SEA with a Kd value of 4 nM. This was a 25 000-fold improvement in affinity compared with the wild-type receptor, which bound to SEA with low affinity (Kd value of 100 µM), similar to other superantigen:Vβ interactions. The SEA:Vβ interface was centered around residues within the complementarity determining region 2 loop. The engineered receptor was specific for SEA, in that it did not bind to two other closely related enterotoxins SEE or SED, providing information on the SEA residues possibly involved in the interaction. The specificity and affinity of these high-affinity Vβ proteins also provide useful agents for the design of more sensitive and specific systems for SEA detection.

  16. Synthesis and Characterization of Tc(I) Carbonyl Nitrosyl Species Relevant to the Hanford Tank Waste: FY 2016 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Gabriel B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Martin, Thibaut J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wall, Nathalie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Walter, Eric D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-24

    Among long-lived radioactive constituents in the Hanford tank waste, Tc presents a unique challenge in that it exists predominantly in the liquid phase, generally in the anionic form of pertechnetate, TcO4-, which is highly volatile at low-activity waste (LAW) vitrification melter temperatures and mobile in the Hanford site’s subsurface environment. The complex behavior of Tc under storage, treatment, and immobilization conditions significantly affects its management options, which to-date remain uncertain. In strongly alkaline environments, Tc exists as pertechnetate, TcO4- (oxidation state +7), and in the reduced forms (oxidation state < +7) collectively known as non-pertechnetate species. Pertechnetate is a well-characterized, anionic Tc species that can be removed from LAW by anion exchange or solvent extraction methods. There is no definitive information on the origin of the non-pertechnetate Tc species, nor is there a comprehensive description of their composition and behavior. It has been recently proposed that the non-pertechnetate species can comprise Tc(I) metal center and carbonyl or mixed carbonyl nitrosyl ligands stabilizing low-valent Tc. Recent work by our group has significantly expanded this previous work, generating a series of Tc(I) carbonyl compounds and demonstrating that they can be generated from reduction of TcO4- in the simulated Hanford tank waste in presence of CO at elevated temperature (Levitskaia et al. 2014). These results are consistent with the previous proposal that [Tc(CO)3]+ species can be present in the Hanford tank waste and suggest that the low Tc(I) oxidation state is stabilized by the π-accepting ability of the CO ligands. The continuation work has been initiated to develop model Tc carbonyl nitrosyl compounds and investigate their potential presence in the Hanford tank wastes. This report summarizes our to-date results.

  17. Busted Butte Unsaturated Zone Transport Test: Fiscal Year 1998 Status Report Yucca Mountain Site Characterization Program Deliverable SPU85M4

    Energy Technology Data Exchange (ETDEWEB)

    Bussod, G.Y.; Turin, H.J.; Lowry, W.E.

    1999-11-01

    This report describes the status of the Busted Butte Unsaturated Zone Transport Test (UZTT) and documents the progress of construction activities and site and laboratory characterization activities undertaken in fiscal year 1998. Also presented are predictive flow-and-transport simulations for Test Phases 1 and 2 of testing and the preliminary results and status of these test phases. Future anticipated results obtained from unsaturated-zone (UZ) transport testing in the Calico Hills Formation at Busted Butte are also discussed in view of their importance to performance assessment (PA) needs to build confidence in and reduce the uncertainty of site-scale flow-and-transport models and their abstractions for performance for license application. The principal objectives of the test are to address uncertainties associated with flow and transport in the UZ site-process models for Yucca Mountain, as identified by the PA working group in February 1997. These include but are not restricted to: (1) The effect of heterogeneities on flow and transport in unsaturated and partially saturated conditions in the Calico Hills Formation. In particular, the test aims to address issues relevant to fracture-matrix interactions and permeability contrast boundaries; (2) The migration behavior of colloids in fractured and unfractured Calico Hills rocks; (3) The validation through field testing of laboratory sorption experiments in unsaturated Calico Hills rocks; (4) The evaluation of the 3-D site-scale flow-and-transport process model (i.e., equivalent-continuum/dual-permeability/discrete-fracture-fault representations of flow and transport) used in the PA abstractions for license application; and (5) The effect of scaling from lab scale to field scale and site scale.

  18. Characterization of the most abundant Lactobacillus species in chicken gastrointestinal tract and potential use as probiotics for genetic engineering.

    Science.gov (United States)

    Wang, Lei; Fang, Mingjian; Hu, Yanping; Yang, Yuxin; Yang, Mingming; Chen, Yulin

    2014-07-01

    The count and diffusion of Lactobacilli species in the different gastrointestinal tract (GI) regions of broilers were investigated by quantitative real-time polymerase chain reaction, and the probiotic characteristics of six L. reuteri species isolated from broilers' GI tract were also investigated to obtain the potential target for genetic engineering. Lactobacilli had the highest diversity in the crop and the lowest one in the cecum. Compared with the lower GI tract, more Lactobacilli were found in the upper GI tract. Lactobacillus reuteri, L. johnsonii, L. acidophilus, L. crispatus, L. salivarius, and L. aviarius were the predominant Lactobacillus species and present throughout the GI tract of chickens. Lactobacillus reuteri was the most abundant Lactobacillus species. Lactobacillus reuteri XC1 had good probiotic characteristics that would be a potential and desirable target for genetic engineering. © The Author 2014. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

  19. Preparation and characterization of a chitosan/galactosylated hyaluronic acid/heparin scaffold for hepatic tissue engineering.

    Science.gov (United States)

    Fan, Jinyong; Yang, Jun

    2017-04-01

    Cell culture microenvironment and hepatocyte-specific three-dimensional tissue-engineering scaffold play important roles for bioartificial liver devices. In the present study, highly porous sponge scaffolds composed of chitosan (CS) and galactosylated hyaluronic acid (GHA, galactose moieties were covalently coupled with hyaluronic acid through ethylenediamine), were prepared by freezing-drying technique. Because the growth factors specifically bind to heparin with a high affinity and biological stability of the growth factors are modulated by heparin. Heparin was added into CS/GHA scaffold under mild conditions. The effects of heparin on the morphology, structure, porosity, mechanical properties of the CS/GHA/heparin scaffold were studied. CS/GHA scaffold containing heparin maintains the porous structure and good mechanical properties. Furthermore, addition of heparin with the growth factors into the scaffold resulted in a significantly improved the microenvironment of cell growth and prolonged liver functions of the hepatocytes such as albumin secretion, urea synthesis and ammonia elimination. These results indicate that this CS/GHA/heparin scaffold is a potential candidate for liver tissue engineering.

  20. Cell-laden 3D bioprinting hydrogel matrix depending on different compositions for soft tissue engineering: Characterization and evaluation.

    Science.gov (United States)

    Park, Jisun; Lee, Sang Jin; Chung, Solchan; Lee, Jun Hee; Kim, Wan Doo; Lee, Jae Young; Park, Su A

    2017-02-01

    Cell-printing techniques that can construct three-dimensional (3D) structures with biocompatible materials and cells are of great interest for various biomedical applications, such as tissue engineering and drug-screening studies. For successful cell-printing with cells, bioinks are critical for both the processability of printing and the viability of printed cells. However, the influence of composition on 3D bio-printing with cells has not been well explored. In this study, we investigated different compositions of alginate bioinks by varying the concentrations of high molecular weight alginate (High Alg) and low molecular weight alginate (Low Alg). Bioinks of 3wt% alginate containing High Alg alone or a 1:2 (Low Alg:High Alg) composite allowed for the construction of 3D scaffolds with good processability and shapes. Cell-printing with fibroblasts and in vitro culture studies revealed good viability and growth of the printed cells after up to 7days of culture. Bioinks prepared with High and Low Alg at a 2:1 ratio exhibited better cell growth compared with those of other compositions. This study progresses the design and applications of alginate-based bioinks for cell-printing platforms in soft tissue engineering. Copyright © 2016. Published by Elsevier B.V.

  1. Polyurethane/fluor-hydroxyapatite nanocomposite scaffolds for bone tissue engineering. Part I: morphological, physical, and mechanical characterization

    Directory of Open Access Journals (Sweden)

    Azadeh Asefnejad

    2011-01-01

    Full Text Available Azadeh Asefnejad1, Aliasghar Behnamghader2, Mohammad Taghi Khorasani3, Babak Farsadzadeh11Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran; 2Materials and Energy Research Center, Tehran, Iran; 3Iran Polymer and Petrochemical Institute, Tehran, IranAbstract: In this study, new nano-fluor-hydroxyapatite (nFHA/polyurethane composite scaffolds were fabricated for potential use in bone tissue engineering. Polyester urethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and 1,4-butanediol as chain extender. Nano fluor-hydroxyapatite (nFHA was successfully synthesized by sol-gel method. The solid–liquid phase separation and solvent sublimation methods were used for preparation of the porous composites. Mechanical properties, chemical structure, and morphological characteristics of the samples were investigated by compressive test, Fourier transform infrared, and scanning electron microscopy (SEM techniques, respectively. The effect of nFHA powder content on porosity and pore morphology was investigated. SEM images demonstrated that the scaffolds were constituted of interconnected and homogeneously distributed pores. The pore size of the scaffolds was in the range 50–250 µm. The result obtained in this research revealed that the porosity and pore average size decreased and compressive modulus increased with nFHA percentage. Considering morphological, physical, and mechanical properties, the scaffold with a higher ratio of nFHA has suitable potential use in tissue regeneration.Keywords: polyester urethane, composite, fluor-hydroxyapatite, scaffold

  2. Engineering food crops to grow in harsh environments [v1; ref status: indexed, http://f1000r.es/5f1

    Directory of Open Access Journals (Sweden)

    Damar López-Arredondo

    2015-09-01

    Full Text Available Achieving sustainable agriculture and producing enough food for the increasing global population will require effective strategies to cope with harsh environments such as water and nutrient stress, high temperatures and compacted soils with high impedance that drastically reduce crop yield. Recent advances in the understanding of the molecular, cellular and epigenetic mechanisms that orchestrate plant responses to abiotic stress will serve as the platform to engineer improved crop plants with better designed root system architecture and optimized metabolism to enhance water and nutrients uptake and use efficiency and/or soil penetration. In this review we discuss such advances and how the generated knowledge could be used to integrate effective strategies to engineer crops by gene transfer or genome editing technologies.

  3. 肌肉组织工程研究现状及对运动性肌肉损伤的作用%Research status and effect of muscle tissue engineering on exercise-induced muscle injury

    Institute of Scientific and Technical Information of China (English)

    王鹏举

    2011-01-01

    背景:高水平快节奏的体育运动比赛中容易造成肌肉运动损伤,肌肉组织工程为其修复带来希望.目的:综述肌肉组织工程研究的现状,为运动性肌肉损伤组织工程学研究提供理论基础.方法:以"tissue engineering,anterior cruciate ligament repair,biological material scaffold,cytokines,seed cells"为关键词,采用计算机检索Pubmed数据库中1994-01/2010-12的相关文章.纳入与运动性肌肉损伤及肌肉组织工程相关的文章;排除重复研究或Meta分析类文章.结果与结论:共纳入15篇文献,目前的研究重点包括肌肉组织工程重建、细胞外基质复合材料、肌肉组织工程种子细胞的来源、基质支架4个方面.目前的研究表明肌肉组织工程对运动性肌肉损伤的治疗有良好的应用前景.但在实际应用中,肌肉组织工程的种子细胞的选择、支架材料的构建、细胞外基质复合材料研究和组织的相容性等仍是肌肉组织工程学方面的难点问题.%BACKGROUND: High levels of fast-paced sports game is Ifcetjr to cause muscle damage which is hopeful to repair because ofmuscle tissue engineering.OBJECTICE: To review the research status of muscle tissue engineering for tissue engineering exercise-induced muscle injurystudies provide a theoretical baric.METHODS: The articles torn PubMed database between January 1W4 and December 2010 were retrieved by computer with thekeywords of tissue engineering, anterior cruciate ligament repair, biological material scaffold, cytokines, seed cells." Atkfcsrelated to exercise-induced muscle damage and muscle tissue engineering were included. Meta-anarysisan dupftatestudieswere excluded.RESULTSAND CONCLUSION: Atotal of 15 literatures were included. Current researches projects in four areas includerebuilding muscle tissue, extracellular matrix composite materials, muscle tissue engineering seed cells sources, matrix scaffold.Current researches show that exercise-induced muscle

  4. Research Status of Genetic Engineering of Herbicide-resistant Plants%抗除草剂植物的基因工程研究现状

    Institute of Scientific and Technical Information of China (English)

    张化霜

    2011-01-01

    With the development of biological genetic engineering,transgenic herbicide-resistant crops have been widely planted all round the world,and great economic profits has been obtained.In this paper,the author reviewed the research of herbicide-resistant plants' genetic engineering as well as main measures and safety appraisal,and pointed out the development prospects of genetic engineering in herbicide-resistant plants.%随着生物基因工程的发展,转基因抗除草剂作物已在世界各地广泛种植并带来巨大的经济效益。综述了抗除草剂植物基因工程的研究概况、主要对策及安全性评估,并探讨了基因工程技术在抗除草剂植物中的发展前景。

  5. Reverse engineering of an affinity-switchable molecular interaction characterized by atomic force microscopy single-molecule force spectroscopy.

    Science.gov (United States)

    Anselmetti, Dario; Bartels, Frank Wilco; Becker, Anke; Decker, Björn; Eckel, Rainer; McIntosh, Matthew; Mattay, Jochen; Plattner, Patrik; Ros, Robert; Schäfer, Christian; Sewald, Norbert

    2008-02-19

    Tunable and switchable interaction between molecules is a key for regulation and control of cellular processes. The translation of the underlying physicochemical principles to synthetic and switchable functional entities and molecules that can mimic the corresponding molecular functions is called reverse molecular engineering. We quantitatively investigated autoinducer-regulated DNA-protein interaction in bacterial gene regulation processes with single atomic force microscopy (AFM) molecule force spectroscopy in vitro, and developed an artificial bistable molecular host-guest system that can be controlled and regulated by external signals (UV light exposure and thermal energy). The intermolecular binding functionality (affinity) and its reproducible and reversible switching has been proven by AFM force spectroscopy at the single-molecule level. This affinity-tunable optomechanical switch will allow novel applications with respect to molecular manipulation, nanoscale rewritable molecular memories, and/or artificial ion channels, which will serve for the controlled transport and release of ions and neutral compounds in the future.

  6. Fabrication and characterization of novel nano-biocomposite scaffold of chitosan–gelatin–alginate–hydroxyapatite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Chhavi, E-mail: chhavisharma19@gmail.com [Department of Polymer and Process Engineering, Indian Institute of Technology Roorkee, Roorkee (India); Dinda, Amit Kumar, E-mail: amit_dinda@yahoo.com [Department of Molecular Medicine and Biology, Jaslok Hospital and Research Centre, Mumbai 400 026 (India); Potdar, Pravin D., E-mail: ppotdar@jaslokhospital.net [Department of Pathology, All India Institute of Medical Sciences, New Delhi 110029 (India); Chou, Chia-Fu, E-mail: cfchou@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Taipei 11529, Taiwan (China); Mishra, Narayan Chandra, E-mail: mishrawise@gmail.com [Department of Polymer and Process Engineering, Indian Institute of Technology Roorkee, Roorkee (India)

    2016-07-01

    A novel nano-biocomposite scaffold was fabricated in bead form by applying simple foaming method, using a combination of natural polymers–chitosan, gelatin, alginate and a bioceramic–nano-hydroxyapatite (nHAp). This approach of combining nHAp with natural polymers to fabricate the composite scaffold, can provide good mechanical strength and biological property mimicking natural bone. Environmental scanning electron microscopy (ESEM) images of the nano-biocomposite scaffold revealed the presence of interconnected pores, mostly spread over the whole surface of the scaffold. The nHAp particulates have covered the surface of the composite matrix and made the surface of the scaffold rougher. The scaffold has a porosity of 82% with a mean pore size of 112 ± 19.0 μm. Swelling and degradation studies of the scaffold showed that the scaffold possesses excellent properties of hydrophilicity and biodegradability. Short term mechanical testing of the scaffold does not reveal any rupturing after agitation under physiological conditions, which is an indicative of good mechanical stability of the scaffold. In vitro cell culture studies by seeding osteoblast cells over the composite scaffold showed good cell viability, proliferation rate, adhesion and maintenance of osteoblastic phenotype as indicated by MTT assay, ESEM of cell–scaffold construct, histological staining and gene expression studies, respectively. Thus, it could be stated that the nano-biocomposite scaffold of chitosan–gelatin–alginate–nHAp has the paramount importance for applications in bone tissue-engineering in future regenerative therapies. - Highlights: • nHAp–chitosan–gelatin–alginate composite scaffold was successfully fabricated. • Foaming method, without surfactant, was applied successfully for fabricating the scaffold. • nHAp provided mechanical stability and nanotopographic features to scaffold matrix. • This scaffold shows good biocompatibility and proliferation with

  7. Characterization of In Vitro Engineered Human Adipose Tissues: Relevant Adipokine Secretion and Impact of TNF-α.

    Science.gov (United States)

    Aubin, Kim; Safoine, Meryem; Proulx, Maryse; Audet-Casgrain, Marie-Alice; Côté, Jean-François; Têtu, Félix-André; Roy, Alphonse; Fradette, Julie

    2015-01-01

    Representative modelling of human adipose tissue functions is central to metabolic research. Tridimensional models able to recreate human adipogenesis in a physiological tissue-like context in vitro are still scarce. We describe the engineering of white adipose tissues reconstructed from their cultured adipose-derived stromal precursor cells. We hypothesize that these reconstructed tissues can recapitulate key functions of AT under basal and pro-inflammatory conditions. These tissues, featuring human adipocytes surrounded by stroma, were stable and metabolically active in long-term cultures (at least 11 weeks). Secretion of major adipokines and growth factors by the reconstructed tissues was determined and compared to media conditioned by human native fat explants. Interestingly, the secretory profiles of the reconstructed adipose tissues indicated an abundant production of leptin, PAI-1 and angiopoietin-1 proteins, while higher HGF levels were detected for the human fat explants. We next demonstrated the responsiveness of the tissues to the pro-inflammatory stimulus TNF-α, as reflected by modulation of MCP-1, NGF and HGF secretion, while VEGF and leptin protein expression did not vary. TNF-α exposure induced changes in gene expression for adipocyte metabolism-associated mRNAs such as SLC2A4, FASN and LIPE, as well as for genes implicated in NF-κB activation. Finally, this model was customized to feature adipocytes representative of progressive stages of differentiation, thereby allowing investigations using newly differentiated or more mature adipocytes. In conclusion, we produced tridimensional tissues engineered in vitro that are able to recapitulate key characteristics of subcutaneous white adipose tissue. These tissues are produced from human cells and their neo-synthesized matrix elements without exogenous or synthetic biomaterials. Therefore, they represent unique tools to investigate the effects of pharmacologically active products on human stromal cells

  8. Characterization of polycyclic aromatic hydrocarbons from the diesel engine by adding light cycle oil to premium diesel fuel.

    Science.gov (United States)

    Lin, Yuan-Chung; Lee, Wen-Jhy; Chen, Chung-Bang

    2006-06-01

    Diesel fuels governed by U.S. regulations are based on the index of the total aromatic contents. Three diesel fuels, containing various fractions of light cycle oil (LCO) and various sulfur, total polyaromatic, and total aromatic contents, were used in a heavy-duty diesel engine (HDDE) under transient cycle test to assess the feasibility of using current indices in managing the emissions of polycyclic aromatic hydrocarbons (PAHs) from HDDE. The mean sulfur content in LCO is 20.8 times as much as that of premium diesel fuel (PDF). The mean total polyaromatic content in LCO is 28.7 times as much as that of PDF, and the mean total aromatic content in LCO is 2.53 times as much as that of PDF. The total polyaromatic hydrocarbon emission factors in the exhaust from the diesel engine, as determined using PDF L3.5 (3.5% LCO and 96.5% PDF), L7.5 (7.5% LCO and 92.5% PDF), and L15 (15% LCO and 85% PDF) were 14.3, 25.8, 44, and 101 mg L(-1), respectively. The total benzo(a)pyrene equivalent (BaPeq) emission factors in the exhaust from PDF, L3.5, L7.5, and L15 were 0.0402, 0.121, 0.219, and 0.548 mg L(-1), respectively. Results indicated that using L3.5 instead of PDF will result in an 80.4% and a 201% increase of emission for total PAHs and total BaPeq, respectively. The relationships between the total polyaromatic hydrocarbon emission factor and the two emission control indices, including fuel polyaromatic content and fuel aromatic content, suggest that both indices could be used feasibly to regulate total PAH emissions. These results strongly suggest that LCO used in the traveling diesel vehicles significantly influences PAH emissions.

  9. Fabrication, characterization and cellular compatibility of poly(hydroxy alkanoate composite nanofibrous scaffolds for nerve tissue engineering.

    Directory of Open Access Journals (Sweden)

    Elahe Masaeli

    Full Text Available Tissue engineering techniques using a combination of polymeric scaffolds and cells represent a promising approach for nerve regeneration. We fabricated electrospun scaffolds by blending of Poly (3-hydroxybutyrate (PHB and Poly (3-hydroxy butyrate-co-3- hydroxyvalerate (PHBV in different compositions in order to investigate their potential for the regeneration of the myelinic membrane. The thermal properties of the nanofibrous blends was analyzed by differential scanning calorimetry (DSC, which indicated that the melting and glass temperatures, and crystallization degree of the blends decreased as the PHBV weight ratio increased. Raman spectroscopy also revealed that the full width at half height of the band centered at 1725 cm(-1 can be used to estimate the crystalline degree of the electrospun meshes. Random and aligned nanofibrous scaffolds were also fabricated by electrospinning of PHB and PHBV with or without type I collagen. The influence of blend composition, fiber alignment and collagen incorporation on Schwann cell (SCs organization and function was investigated. SCs attached and proliferated over all scaffolds formulations up to 14 days. SCs grown on aligned PHB/PHBV/collagen fibers exhibited a bipolar morphology that oriented along the fiber direction, while SCs grown on the randomly oriented fibers had a multipolar morphology. Incorporation of collagen within nanofibers increased SCs proliferation on day 14, GDNF gene expression on day 7 and NGF secretion on day 6. The results of this study demonstrate that aligned PHB/PHBV electrospun nanofibers could find potential use as scaffolds for nerve tissue engineering applications and that the presence of type I collagen in the nanofibers improves cell differentiation.

  10. Characterization of In Vitro Engineered Human Adipose Tissues: Relevant Adipokine Secretion and Impact of TNF-α

    Science.gov (United States)

    Aubin, Kim; Safoine, Meryem; Proulx, Maryse; Audet-Casgrain, Marie-Alice; Côté, Jean-François; Têtu, Félix-André; Roy, Alphonse; Fradette, Julie

    2015-01-01

    Representative modelling of human adipose tissue functions is central to metabolic research. Tridimensional models able to recreate human adipogenesis in a physiological tissue-like context in vitro are still scarce. We describe the engineering of white adipose tissues reconstructed from their cultured adipose-derived stromal precursor cells. We hypothesize that these reconstructed tissues can recapitulate key functions of AT under basal and pro-inflammatory conditions. These tissues, featuring human adipocytes surrounded by stroma, were stable and metabolically active in long-term cultures (at least 11 weeks). Secretion of major adipokines and growth factors by the reconstructed tissues was determined and compared to media conditioned by human native fat explants. Interestingly, the secretory profiles of the reconstructed adipose tissues indicated an abundant production of leptin, PAI-1 and angiopoietin-1 proteins, while higher HGF levels were detected for the human fat explants. We next demonstrated the responsiveness of the tissues to the pro-inflammatory stimulus TNF-α, as reflected by modulation of MCP-1, NGF and HGF secretion, while VEGF and leptin protein expression did not vary. TNF-α exposure induced changes in gene expression for adipocyte metabolism-associated mRNAs such as SLC2A4, FASN and LIPE, as well as for genes implicated in NF-κB activation. Finally, this model was customized to feature adipocytes representative of progressive stages of differentiation, thereby allowing investigations using newly differentiated or more mature adipocytes. In conclusion, we produced tridimensional tissues engineered in vitro that are able to recapitulate key characteristics of subcutaneous white adipose tissue. These tissues are produced from human cells and their neo-synthesized matrix elements without exogenous or synthetic biomaterials. Therefore, they represent unique tools to investigate the effects of pharmacologically active products on human stromal cells

  11. Preparation and characterization of electrospun PLCL/Poloxamer nanofibers and dextran/gelatin hydrogels for skin tissue engineering.

    Directory of Open Access Journals (Sweden)

    Jian-feng Pan

    Full Text Available In this study, two different biomaterials were fabricated and their potential use as a bilayer scaffold for skin tissue engineering applications was assessed. The upper layer biomaterial was a Poly(ε-caprolactone-co-lactide/Poloxamer (PLCL/Poloxamer nanofiber membrane fabricated using electrospinning technology. The PLCL/Poloxamer nanofibers (PLCL/Poloxamer, 9/1 exhibited strong mechanical properties (stress/strain values of 9.37 ± 0.38 MPa/187.43 ± 10.66% and good biocompatibility to support adipose-derived stem cells proliferation. The lower layer biomaterial was a hydrogel composed of 10% dextran and 20% gelatin without the addition of a chemical crosslinking agent. The 5/5 dextran/gelatin hydrogel displayed high swelling property, good compressive strength, capacity to present more than 3 weeks and was able to support cells proliferation. A bilayer scaffold was fabricated using these two materials by underlaying the nanofibers and casting hydrogel to mimic the structure and biological function of native skin tissue. The upper layer membrane provided mechanical support in the scaffold and the lower layer hydrogel provided adequate space to allow cells to proliferate and generate extracellular matrix. The biocompatibility of bilayer scaffold was preliminarily investigated to assess the potential cytotoxicity. The results show that cell viability had not been affected when cocultured with bilayer scaffold. As a consequence, the bilayer scaffold composed of PLCL/Poloxamer nanofibers and dextran/gelatin hydrogels is biocompatible and possesses its potentially high application prospect in the field of skin tissue engineering.

  12. Polydimethylsiloxane films doped with NdFeB powder: magnetic characterization and potential applications in biomedical engineering and microrobotics.

    Science.gov (United States)

    Iacovacci, V; Lucarini, G; Innocenti, C; Comisso, N; Dario, P; Ricotti, L; Menciassi, A

    2015-12-01

    This work reports the fabrication, magnetic characterization and controlled navigation of film-shaped microrobots consisting of a polydimethylsiloxane-NdFeB powder composite material. The fabrication process relies on spin-coating deposition, powder orientation and permanent magnetization. Films with different powder concentrations (10 %, 30 %, 50 % and 70 % w/w) were fabricated and characterized in terms of magnetic properties and magnetic navigation performances (by exploiting an electromagnet-based platform). Standardized data are provided, thus enabling the exploitation of these composite materials in a wide range of applications, from MEMS/microrobot development to biomedical systems. Finally, the possibility to microfabricate free-standing polymeric structures and the biocompatibility of the proposed composite materials is demonstrated.

  13. Engineering geological characterization of volcanic rocks of ethiopian and sardinian highlands to be used as construction materials

    OpenAIRE

    Engidasew, Tesfaye Asresahagne

    2014-01-01

    This thesis presents the results of the study conducted on the “Geoengineering characterization of volcanic rocks from Ethiopian and Sardinian highlands to be used as construction materials”. Though, the two project areas are geographically far apart, both are partly covered with volcanic rocks mainly consisting of basic and subordinate felsic rocks. The research was conducted in two countries; part I, the Ethiopian Project area located on the northwestern central Highlands of ...

  14. Preparation and chemical and biological characterization of a pectin/chitosan polyelectrolyte complex scaffold for possible bone tissue engineering applications.

    Science.gov (United States)

    Coimbra, P; Ferreira, P; de Sousa, H C; Batista, P; Rodrigues, M A; Correia, I J; Gil, M H

    2011-01-01

    In this work, porous scaffolds obtained from the freeze-drying of pectin/chitosan polyelectrolyte complexes were prepared and characterized by FTIR, SEM and weight loss studies. Additionally, the cytotoxicity of the prepared scaffolds was evaluated in vitro, using human osteoblast cells. The results obtained showed that cells adhered to scaffolds and proliferated. The study also confirmed that the degradation by-products of pectin/chitosan scaffold are noncytotoxic.

  15. Characterization of inhalable, thoracic, and respirable fractions and ultrafine particle exposure during grinding, brazing, and welding activities in a mechanical engineering factory.

    Science.gov (United States)

    Iavicoli, Ivo; Leso, Veruscka; Fontana, Luca; Cottica, Danilo; Bergamaschi, Antonio

    2013-04-01

    To investigate the emission sources of fine and ultrafine particles (UFPs) during brazing, welding, and grinding in a mechanical engineering factory and to characterize UFP exposure by measuring size distributions, number, and surface area concentrations. Samplings lasted 4 hours and were conducted during 5 days using the Grimm 1.109 portable aerosol spectrometer, the Grimm portable NanoCheck™ 1.320, the electrical low pressure impactor, and the nanoparticle aerosol monitor AeroTrak™ 9000. Higher concentrations of fine particles were observed in welding and grinding activities. The highest values of UFP number and alveolar surface area concentrations were detected in the welding booth. Potential emission sources of fine particles and UFPs can be identified by the multifaceted approach outlined in this study. This sampling strategy provides important data on key UFP metrics.

  16. Fabrication and characterization of Antheraea pernyi silk fibroin-blended P(LLA-CL) nanofibrous scaffolds for peripheral nerve tissue engineering

    Science.gov (United States)

    Wang, Juan; Sun, Binbin; Bhutto, Muhammad Aqeel; Zhu, Tonghe; Yu, Kui; Bao, Jiayu; Morsi, Yosry; El-Hamshary, Hany; El-Newehy, Mohamed; Mo, Xiumei

    2017-03-01

    Electrospun nanofibers have gained widespreading interest for tissue engineering application. In the present study, ApF/P(LLA-CL) nanofibrous scaffolds were fabricated via electrospinning. The feasibility of the material as tissue engineering nerve scaffold was investigated in vitro. The average diameter increased with decreasing the blend ratio of ApF to P(LLA-CL). Characterization of 13C NMR and FTIR clarified that there is no obvious chemical bond reaction between ApF and P(LLA-CL). The tensile strength and elongation at break increased with the content increase of P(LLA-CL). The surface hydrophilic property of nanofibrous scaffolds enhanced with the increased content of ApF. Cell viability studies with Schwann cells demonstrated that ApF/P(LLA-CL) blended nanofibrous scaffolds significantly promoted cell growth as compare to P(LLA-CL), especially when the weight ratio of ApF to P(LLA-CL) was 25:75. The present work provides a basis for further studies of this novel nanofibrous material (ApF/P(LLA-CL)) in peripheral nerve tissue repair or regeneration.

  17. Fabrication and characterization of Antheraea pernyi silk fibroin-blended P(LLA-CL) nanofibrous scaffolds for peripheral nerve tissue engineering

    Science.gov (United States)

    Wang, Juan; Sun, Binbin; Bhutto, Muhammad Aqeel; Zhu, Tonghe; Yu, Kui; Bao, Jiayu; Morsi, Yosry; El-Hamshary, Hany; El-Newehy, Mohamed; Mo, Xiumei

    2017-01-01

    Electrospun nanofibers have gained widespreading interest for tissue engineering application. In the present study, ApF/P(LLA-CL) nanofibrous scaffolds were fabricated via electrospinning. The feasibility of the material as tissue engineering nerve scaffold was investigated in vitro. The average diameter increased with decreasing the blend ratio of ApF to P(LLA-CL). Characterization of 13C NMR and FTIR clarified that there is no obvious chemical bond reaction between ApF and P(LLA-CL). The tensile strength and elongation at break increased with the content increase of P(LLA-CL). The surface hydrophilic property of nanofibrous scaffolds enhanced with the increased content of ApF. Cell viability studies with Schwann cells demonstrated that ApF/P(LLA-CL) blended nanofibrous scaffolds significantly promoted cell growth as compare to P(LLA-CL), especially when the weight ratio of ApF to P(LLA-CL) was 25:75. The present work provides a basis for further studies of this novel nanofibrous material (ApF/P(LLA-CL)) in peripheral nerve tissue repair or regeneration.

  18. Molecular characterization, expression and methylation status analysis of BMP4 gene in skin tissue of Liaoning cashmere goat during hair follicle cycle.

    Science.gov (United States)

    Bai, Wen L; Dang, Yun L; Wang, Jiao J; Yin, Rong H; Wang, Ze Y; Zhu, Yu B; Cong, Yu Y; Xue, Hui L; Deng, Liang; Guo, Dan; Wang, Shi Q; Yang, Shu H

    2016-08-01

    Bone morphogenetic protein 4 (BMP4) is a member of the bone morphogenetic protein family (BMPs). It is involved in the development and cycle of hair follicle, as well as, is thought to be a potential candidate gene for cashmere traits in goats. In the present study, we isolated and characterized a full-length open reading frame (ORF) of BMP4 cDNA from the skin tissue of Liaoning cashmere goat, and investigated the transcriptional pattern and methylation status of BMP4 gene in skin tissue of this breed during different stages of hair follicle cycle. The sequence analysis indicated that the isolated cDNA was 1264-bp in length containing a complete ORF of 1230-bp. It encoded a precursor peptide of 409 amino acids with a signal peptide of 19 amino acids. The structural analysis indicated that goat BMP4 contains typical TGF-β propeptide and TGF-β domains. In skin tissue, BMP4 is generally transcribed in an ascendant pattern from anagen to telogen. The methylation level of 5' flanking regulatory region of BMP4 gene might be involved in its mRNA expression in skin tissue: a higher BMP4 methylation level in skin coincides with a lower expression of BMP4 mRNA. These results from the present work provided a foundation for further insight into the functional and regulatory characteristics of BMP4 in the development and cycle of hair follicle in Liaoning Cashmere goat.

  19. Characterization and engineering of the biosynthesis gene cluster for antitumor macrolides PM100117 and PM100118 from a marine actinobacteria: generation of a novel improved derivative.

    Science.gov (United States)

    Salcedo, Raúl García; Olano, Carlos; Gómez, Cristina; Fernández, Rogelio; Braña, Alfredo F; Méndez, Carmen; de la Calle, Fernando; Salas, José A

    2016-02-22

    PM100117 and PM100118 are glycosylated polyketides with remarkable antitumor activity, which derive from the marine symbiotic actinobacteria Streptomyces caniferus GUA-06-05-006A. Structurally, PM100117 and PM100118 are composed of a macrocyclic lactone, three deoxysugar units and a naphthoquinone (NQ) chromophore that shows a clear structural similarity to menaquinone. Whole-genome sequencing of S. caniferus GUA-06-05-006A has enabled the identification of PM100117 and PM100118 biosynthesis gene cluster, which has been characterized on the basis of bioinformatics and genetic engineering data. The product of four genes shows high identity to proteins involved in the biosynthesis of menaquinone via futalosine. Deletion of one of these genes led to a decay in PM100117 and PM100118 production, and to the accumulation of several derivatives lacking NQ. Likewise, five additional genes have been genetically characterized to be involved in the biosynthesis of this moiety. Moreover, the generation of a mutant in a gene coding for a putative cytochrome P450 has led to the production of PM100117 and PM100118 structural analogues showing an enhanced in vitro cytotoxic activity relative to the parental products. Although a number of compounds structurally related to PM100117 and PM100118 has been discovered, this is, to our knowledge, the first insight reported into their biosynthesis. The structural resemblance of the NQ moiety to menaquinone, and the presence in the cluster of four putative menaquinone biosynthetic genes, suggests a connection between the biosynthesis pathways of both compounds. The availability of the PM100117 and PM100118 biosynthetic gene cluster will surely pave a way to the combinatorial engineering of more derivatives.

  20. Infrared Camera Characterization of Bi-Propellant Reaction Control Engines during Auxiliary Propulsion Systems Tests at NASA's White Sands Test Facility in Las Cruces, New Mexico

    Science.gov (United States)

    Holleman, Elizabeth; Sharp, David; Sheller, Richard; Styron, Jason

    2007-01-01

    This paper describes the application of a FUR Systems A40M infrared (IR) digital camera for thermal monitoring of a Liquid Oxygen (LOX) and Ethanol bi-propellant Reaction Control Engine (RCE) during Auxiliary Propulsion System (APS) testing at the National Aeronautics & Space Administration's (NASA) White Sands Test Facility (WSTF) near Las Cruces, New Mexico. Typically, NASA has relied mostly on the use of ThermoCouples (TC) for this type of thermal monitoring due to the variability of constraints required to accurately map rapidly changing temperatures from ambient to glowing hot chamber material. Obtaining accurate real-time temperatures in the JR spectrum is made even more elusive by the changing emissivity of the chamber material as it begins to glow. The parameters evaluated prior to APS testing included: (1) remote operation of the A40M camera using fiber optic Firewire signal sender and receiver units; (2) operation of the camera inside a Pelco explosion proof enclosure with a germanium window; (3) remote analog signal display for real-time monitoring; (4) remote digital data acquisition of the A40M's sensor information using FUR's ThermaCAM Researcher Pro 2.8 software; and (5) overall reliability of the system. An initial characterization report was prepared after the A40M characterization tests at Marshall Space Flight Center (MSFC) to document controlled heat source comparisons to calibrated TCs. Summary IR digital data recorded from WSTF's APS testing is included within this document along with findings, lessons learned, and recommendations for further usage as a monitoring tool for the development of rocket engines.

  1. Engineering Stem Cells for Biomedical Applications.

    Science.gov (United States)

    Yin, Perry T; Han, Edward; Lee, Ki-Bum

    2016-01-07

    Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer.

  2. Engineering Encounters: Engineering Adaptations

    Science.gov (United States)

    Gatling, Anne; Vaughn, Meredith Houle

    2015-01-01

    Engineering is not a subject that has historically been taught in elementary schools, but with the emphasis on engineering in the "Next Generation Science Standards," curricula are being developed to explicitly teach engineering content and design. However, many of the scientific investigations already conducted with students have…

  3. Engineering Encounters: Engineering Adaptations

    Science.gov (United States)

    Gatling, Anne; Vaughn, Meredith Houle

    2015-01-01

    Engineering is not a subject that has historically been taught in elementary schools, but with the emphasis on engineering in the "Next Generation Science Standards," curricula are being developed to explicitly teach engineering content and design. However, many of the scientific investigations already conducted with students have…

  4. Discussion on the Asphalt Mixing Equipment Status of Traffic Engineering Machinery%浅议交通工程机械沥青搅拌设备现状

    Institute of Scientific and Technical Information of China (English)

    李新亚

    2013-01-01

    In the construction of asphalt pavement, asphalt mixing machine is one of the most important construction equ-ipment, its application market has a large range in our country. This paper discusses the asphalt mixing equipment status.%  在沥青路面的施工中,沥青混合料搅拌机械是最为重要的施工设备,在我国有着大范围的应用市场。在文中将对公路施工沥青搅拌设备的现状进行讨论。

  5. Characterization of partially hydrolyzed OCP crystals deposited in a gelatin matrix as a scaffold for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Ezoe, Yushi [Tohoku University Graduate School of Dentistry, Division of Oral and Maxillofacial Surgery (Japan); Anada, Takahisa [Tohoku University Graduate School of Dentistry, Division of Craniofacial Function Engineering (Japan); Yamazaki, Hajime [The Forsyth Institute, Department of Applied Oral Sciences, Center for Biomineralization (United States); Handa, Takuto; Kobayashi, Kazuhito; Takahashi, Tetsu [Tohoku University Graduate School of Dentistry, Division of Oral and Maxillofacial Surgery (Japan); Suzuki, Osamu, E-mail: suzuki-o@m.tohoku.ac.jp [Tohoku University Graduate School of Dentistry, Division of Craniofacial Function Engineering (Japan)

    2015-03-15

    The present study was designed to investigate how hydrolysis of octacalcium phosphate (OCP) into hydroxyapatite is affected by the presence of gelatin (Gel) molecules and how osteoblastic cells respond to the resultant OCP hydrolyzate/Gel composites as the hydrolysis advances. OCP was prepared from a solution containing calcium and phosphate ions and Gel molecules, having a composition to produce a 40 wt% OCP as a final co-precipitate as the OCP/Gel. The precipitate was further incubated up to 40 h to advance the hydrolysis of OCP. These precipitates were processed to mold OCP/Gel sponges through lyophilization and dehydrothermal treatment. Chemical analysis, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and selected area electron diffraction revealed that the hydrolysis of OCP/Gel composite in hot water advanced in a time-dependent manner and faster than hydrolysis of OCP alone. The effect of Gel on the OCP hydrolysis was further examined in the presence of distinct concentrations of Gel molecules in hot water, showing that the Gel enhanced the hydrolysis as the concentration increased. Proliferation and differentiation of mouse bone marrow stromal ST-2 cells on the hydrolyzed OCP/Gel composites were compatible with Gel sponge alone after 21 days of culture, suggesting that these composites could be a candidate as a scaffold in bone tissue engineering.

  6. Polyurethane/fluor-hydroxyapatite nanocomposite scaffolds for bone tissue engineering. Part I: morphological, physical, and mechanical characterization.

    Science.gov (United States)

    Asefnejad, Azadeh; Behnamghader, Aliasghar; Khorasani, Mohammad Taghi; Farsadzadeh, Babak

    2011-01-06

    In this study, new nano-fluor-hydroxyapatite (nFHA)/polyurethane composite scaffolds were fabricated for potential use in bone tissue engineering. Polyester urethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and 1,4-butanediol as chain extender. Nano fluor-hydroxyapatite (nFHA) was successfully synthesized by sol-gel method. The solid-liquid phase separation and solvent sublimation methods were used for preparation of the porous composites. Mechanical properties, chemical structure, and morphological characteristics of the samples were investigated by compressive test, Fourier transform infrared, and scanning electron microscopy (SEM) techniques, respectively. The effect of nFHA powder content on porosity and pore morphology was investigated. SEM images demonstrated that the scaffolds were constituted of interconnected and homogeneously distributed pores. The pore size of the scaffolds was in the range 50-250 μm. The result obtained in this research revealed that the porosity and pore average size decreased and compressive modulus increased with nFHA percentage. Considering morphological, physical, and mechanical properties, the scaffold with a higher ratio of nFHA has suitable potential use in tissue regeneration.

  7. Genetically engineered silk-collagen-like copolymer for biomedical applications: production, characterization and evaluation of cellular response.

    Science.gov (United States)

    Włodarczyk-Biegun, Małgorzata K; Werten, Marc W T; de Wolf, Frits A; van den Beucken, Jeroen J J P; Leeuwenburgh, Sander C G; Kamperman, Marleen; Cohen Stuart, Martien A

    2014-08-01

    Genetically engineered protein polymers (GEPP) are a class of multifunctional materials with precisely controlled molecular structure and property profile. Representing a promising alternative for currently used materials in biomedical applications, GEPP offer multiple benefits over natural and chemically synthesized polymers. However, producing them in sufficient quantities for preclinical research remains challenging. Here, we present results from an in vitro cellular response study of a recombinant protein polymer that is soluble at low pH but self-organizes into supramolecular fibers and physical hydrogels at neutral pH. It has a triblock structure denoted as C2S(H)48C2, which consists of hydrophilic collagen-inspired and histidine-rich silk-inspired blocks. The protein was successfully produced by the yeast Pichia pastoris in laboratory-scale bioreactors, and it was purified by selective precipitation. This efficient and inexpensive production method provided material of sufficient quantities, purity and sterility for cell culture study. Rheology and erosion studies showed that it forms hydrogels exhibiting long-term stability, self-healing behavior and tunable mechanical properties. Primary rat bone marrow cells cultured in direct contact with these hydrogels remained fully viable; however, proliferation and mineralization were relatively low compared to collagen hydrogel controls, probably because of the absence of cell-adhesive motifs. As biofunctional factors can be readily incorporated to improve material performance, our approach provides a promising route towards biomedical applications.

  8. Fabrication and characterization of a novel microparticle with gyrus-patterned surface and growth factor delivery for cartilage tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Huang Sha [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Wang Yijuan [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Liang Tang [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China); Jin Fang [Department of Orthodontics, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Liu Shouxin [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi' an 710062 (China); Jin Yan, E-mail: yanjin@fmmu.edu.cn [Department of Oral Histology and Pathology, School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Research and Development Center for Tissue Engineering, Fourth Military Medical University, Xi' an 710032 (China)

    2009-05-05

    Microparticles can serve as substrates for cell amplification and deliver the expanded cells to the site of the defect. It was hypothesized that a novel microparticle combined of sustained and localized delivery of proliferative growth factors and gyrus-patterned surface would influence the cell behaviours of adherence and expansion on the microparticle in the present study. To test the hypothesis, gelatin particles with diameter ranging from 280 to 350 {mu}m were fabricated and were modified by cryogenic freeze-drying treatment and basic fibroblast growth factor (bFGF) incorporation. The results of in vitro chondrocyte culture illustrated that cells could proliferate more obviously on the microparticles with bFGF addition, but no correlation between attachment rate and bFGF was observed. On the other hand, microparticles with gyrus-patterned surface demonstrated the highest cell attachment rate and higher rate of cell growth, in particular on bFGF combined ones. It seems to be a promising candidate as a chondrocyte microparticle and could be the potential application in cartilage tissue engineering.

  9. Chemical Synthesis, Characterization, and Biocompatibility Study of Hydroxyapatite/Chitosan Phosphate Nanocomposite for Bone Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Nabakumar Pramanik

    2009-01-01

    Full Text Available A novel bioanalogue hydroxyapatite (HAp/chitosan phosphate (CSP nanocomposite has been synthesized by a solution-based chemical methodology with varying HAp contents from 10 to 60% (w/w. The interfacial bonding interaction between HAp and CSP has been investigated through Fourier transform infrared absorption spectra (FTIR and x-ray diffraction (XRD. The surface morphology of the composite and the homogeneous dispersion of nanoparticles in the polymer matrix have been investigated through scanning electron microscopy (SEM and transmission electron microscopy (TEM, respectively. The mechanical properties of the composite are found to be improved significantly with increase in nanoparticle contents. Cytotoxicity test using murine L929 fibroblast confirms that the nanocomposite is cytocompatible. Primary murine osteoblast cell culture study proves that the nanocomposite is osteocompatible and highly in vitro osteogenic. The use of CSP promotes the homogeneous distribution of particles in the polymer matrix through its pendant phosphate groups along with particle-polymer interfacial interactions. The prepared HAp/CSP nanocomposite with uniform microstructure may be used in bone tissue engineering applications.

  10. Fabrication and characterization of novel nano-biocomposite scaffold of chitosan-gelatin-alginate-hydroxyapatite for bone tissue engineering.

    Science.gov (United States)

    Sharma, Chhavi; Dinda, Amit Kumar; Potdar, Pravin D; Chou, Chia-Fu; Mishra, Narayan Chandra

    2016-07-01

    A novel nano-biocomposite scaffold was fabricated in bead form by applying simple foaming method, using a combination of natural polymers-chitosan, gelatin, alginate and a bioceramic-nano-hydroxyapatite (nHAp). This approach of combining nHAp with natural polymers to fabricate the composite scaffold, can provide good mechanical strength and biological property mimicking natural bone. Environmental scanning electron microscopy (ESEM) images of the nano-biocomposite scaffold revealed the presence of interconnected pores, mostly spread over the whole surface of the scaffold. The nHAp particulates have covered the surface of the composite matrix and made the surface of the scaffold rougher. The scaffold has a porosity of 82% with a mean pore size of 112±19.0μm. Swelling and degradation studies of the scaffold showed that the scaffold possesses excellent properties of hydrophilicity and biodegradability. Short term mechanical testing of the scaffold does not reveal any rupturing after agitation under physiological conditions, which is an indicative of good mechanical stability of the scaffold. In vitro cell culture studies by seeding osteoblast cells over the composite scaffold showed good cell viability, proliferation rate, adhesion and maintenance of osteoblastic phenotype as indicated by MTT assay, ESEM of cell-scaffold construct, histological staining and gene expression studies, respectively. Thus, it could be stated that the nano-biocomposite scaffold of chitosan-gelatin-alginate-nHAp has the paramount importance for applications in bone tissue-engineering in future regenerative therapies.

  11. Fabrication and characterization of chitosan/OGP coated porous poly(ε-caprolactone) scaffold for bone tissue engineering.

    Science.gov (United States)

    Cui, Zhixiang; Lin, Luyin; Si, Junhui; Luo, Yufei; Wang, Qianting; Lin, Yongnan; Wang, Xiaofeng; Chen, Wenzhe

    2017-03-14

    As one of the stimulators on bone formation, osteogenic growth peptide (OGP) improves both proliferation and differentiation of the bone cells in vitro and in vivo. The aim of this work was the preparation of three dimensional porous poly(ε-caprolactone) (PCL) scaffold with high porosity, well interpore connectivity, and then its surface was modified by using chitosan (CS)/OGP coating for application in bone regeneration. In present study, the properties of porous PCL and CS/OGP coated PCL scaffold, including the microstructure, water absorption, porosity, hydrophilicity, mechanical properties, and biocompatibility in vitro were investigated. Results showed that the PCL and CS/OGP-PCL scaffold with an interconnected network structure have a porosity of more than 91.5, 80.8%, respectively. The CS/OGP-PCL scaffold exhibited better hydrophilicity and mechanical properties than that of uncoated PCL scaffold. Moreover, the results of cell culture test showed that CS/OGP coating could stimulate the proliferation and growth of osteoblast cells on CS/OGP-PCL scaffold. These finding suggested that the surface modification could be a effective method on enhancing cell adhesion to synthetic polymer-based scaffolds in tissue engineering application and the developed porous CS/OGP-PCL scaffold should be considered as alternative biomaterials for bone regeneration.

  12. Characterization, mechanical behavior and in vitro evaluation of a melt-drawn scaffold for esophageal tissue engineering.

    Science.gov (United States)

    Tan, Yu Jun; Yeong, Wai Yee; Tan, Xipeng; An, Jia; Chian, Kerm Sin; Leong, Kah Fai

    2016-04-01

    Tubular esophageal scaffolds with fiber diameter ranging from 13.9±1.7μm to 65.7±6.2μm were fabricated from the highly elastic poly(l-lactide-co-ε-caprolactone) (PLC) via a melt-drawing method. The morphology, crystallinity, thermal and mechanical properties of the PLC fibers were investigated. They were highly aligned and have a uniform diameter. PLC is found to be semicrystalline consisting of α- and β- lactide (LA) crystals. The crystallinity increases up to 16.8% with increasing melt-drawing speeds due to strain-induced crystallization. Modulus and strength increases while ductility decreases with an increase in crystallinity of the PLC samples. Moisture will not degrade the overall tensile properties but affect its tangent modulus at the low strain. L929 cells are able to attach and proliferate on the scaffolds very well. The cells seeded on the scaffolds show normal morphology with >90% cell viability after 6 days of culture. These results demonstrate that the PLC fibrous scaffold has good potential for use in esophageal tissue engineering application.

  13. Polyurethane/fluor-hydroxyapatite nanocomposite scaffolds for bone tissue engineering. Part I: morphological, physical, and mechanical characterization

    Science.gov (United States)

    Asefnejad, Azadeh; Behnamghader, Aliasghar; Khorasani, Mohammad Taghi; Farsadzadeh, Babak

    2011-01-01

    In this study, new nano-fluor-hydroxyapatite (nFHA)/polyurethane composite scaffolds were fabricated for potential use in bone tissue engineering. Polyester urethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and 1,4-butanediol as chain extender. Nano fluor-hydroxyapatite (nFHA) was successfully synthesized by sol-gel method. The solid–liquid phase separation and solvent sublimation methods were used for preparation of the porous composites. Mechanical properties, chemical structure, and morphological characteristics of the samples were investigated by compressive test, Fourier transform infrared, and scanning electron microscopy (SEM) techniques, respectively. The effect of nFHA powder content on porosity and pore morphology was investigated. SEM images demonstrated that the scaffolds were constituted of interconnected and homogeneously distributed pores. The pore size of the scaffolds was in the range 50–250 μm. The result obtained in this research revealed that the porosity and pore average size decreased and compressive modulus increased with nFHA percentage. Considering morphological, physical, and mechanical properties, the scaffold with a higher ratio of nFHA has suitable potential use in tissue regeneration. PMID:21289986

  14. Preparation, characterization and biological test of 3D-scaffolds based on chitosan, fibroin and hydroxyapatite for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Paulo Autran Leite; Resende, Cristiane Xavier [Departamento de Ciências de Materiais, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n. Jardim Rosa Elze, São Cristóvão, Sergipe CEP 49000-100 (Brazil); Dulce de Almeida Soares, Glória [Departamento de Ciências de Materiais, Universidade Federal do Rio de Janeiro, Av. Brigadeiro Trompowisk, s/n. Ilha do Fundão, Rio de Janeiro, Rio de Janeiro CEP 21900-000 (Brazil); Anselme, Karine [Institut de Science des Matériaux de Mulhouse (IS2M), CNRS LRC7228, 15, Jean Starcky Street, BP 2488, 68054 Mulhouse cedex (France); Almeida, Luís Eduardo, E-mail: lealmeida2009@gmail.com [Departamento de Ciências de Materiais, Universidade Federal de Sergipe, Av. Marechal Rondon, s/n. Jardim Rosa Elze, São Cristóvão, Sergipe CEP 49000-100 (Brazil)

    2013-08-01

    This work describes the preparation and characterization of porous 3D-scaffolds based on chitosan (CHI), chitosan/silk fibroin (CHI/SF) and chitosan/silk fibroin/hydroxyapatite (CHI/SF/HA) by freeze drying. The biomaterials were characterized by X-ray diffraction, attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy and energy dispersive spectroscopy. In addition, studies of porosity, pore size, contact angle and biological response of SaOs-2osteoblastic cells were performed. The CHI scaffolds have a porosity of 94.2 ± 0.9%, which is statistically higher than the one presented by CHI/SF/HA scaffolds, 89.7 ± 2.6%. Although all scaffolds were able to promote adhesion, growth and maintenance of osteogenic differentiation of SaOs-2 cells, the new 3D-scaffold based on CHI/SF/HA showed a significantly higher cell growth at 7 days and 21 days and the level of alkaline phosphatase at 14 and 21 days was statistically superior compared to other tested materials. - Highlights: • Preparation of 3D-scaffolds based on CHI, with or without addition of SF and HA. • Scaffolds exhibited interconnected porous structure (pore size superior to 50 μm). • The tripolyphosphate did not induce any significant cytotoxic response. • The CHI/SF/HA composite showed a higher cell growth and ALP activity.

  15. An integrated geologic and engineering reservoir characterization of the North Robertson (Clearfork) unit: A case study, part 1

    Energy Technology Data Exchange (ETDEWEB)

    Doublet, L.E.; Blasingame, T.A. [Texas A and M Univ., College Station, TX (United States); Pande, P.K.; Clark, M.B.; Nevans, J.W.

    1995-12-31

    Infill drilling of wells on a uniform spacing, without regard to reservoir performance and characterization, must become a process of the past. Such efforts do not optimize reservoir development as they fail to account for the complex nature of reservoir heterogeneities present in many low permeability carbonate reservoirs. New and emerging technologies such as cross-borehole tomography, geostatistical modeling, and rigorous decline type curve analysis can be used to quantify reservoir quality and the degree of interwell communication. These results can be used to develop a 3-D simulation model for prediction of infill locations. In this work, the authors will demonstrate the application of reservoir surveillance techniques to identify additional reservoir ``pay`` zones, and to monitor pressure and preferential fluid movement in the reservoir. These techniques are: long-term production and injection data analysis, pressure transient analysis, and advanced open and cased hole well log analysis. The major contribution of this paper is the summary of cost effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability carbonate reservoirs such as the North Robertson (Clearfork) Unit.

  16. 冶金工程设计的发展现状及展望%Current Status and Expectations of Metallurgical Engineering Design

    Institute of Scientific and Technical Information of China (English)

    张福明; 颉建新

    2014-01-01

    The Chinese metallurgical engineering design plays an important role for promoting sustainable development of metallurgical industry. China has already possessed the expertise of process design, plant design and equipment design as well as the technical know-how of system integration for modern large-scale steel plants, and it has created and put into application a dynamic-precision engineering system. A new generation of circulating steel plant, advanced by international standard, is designed and built. These metallurgical plants feature significantly high-efficient process, intensive produc-tion, large-scale equipment, etc. With the development of these metallurgical plants, a system of engineering philosophy, theory and method for metallurgical plant is established. And at the same time, significant breakthroughs in key-unit metal-lurgical technology and engineering integration are made;a series of scientific-technological achievements in various tech-nical fields of key technologies, common technologies and significant technologies are acquired, providing effective sup-port to the theory development and practice of the studies of metallurgical plant design. In the coming period, the metallur-gical process engineering and the theory and method of dynamic-precision should be centered, to establish a comprehen-sive system of philosophy, theory and design method for metallurgical plant design innovation.%冶金工程设计对促进冶金工业的可持续发展具有特殊的重要作用。中国已经具备了现代大型钢铁厂的流程设计、工艺设计、设备设计以及系统集成能力,创建并应用动态-精准设计体系,建立了现代冶金厂工程设计理念、理论和设计方法,设计建设了具有国际先进水平的新一代可循环钢铁厂,在流程高效化、生产集约化、装备大型化等方面取得显著成效。与此同时,冶金关键单元技术和工程化集成技术得到重点突破,在关键、共

  17. Preliminary Exploration of Practice Teaching Status in Unique Biological Engineering Talents Training%实践教学在生物工程专业特色人才培养中的作用初探

    Institute of Scientific and Technical Information of China (English)

    于大禹; 刘月华; 魏群; 赵晴潇

    2009-01-01

    从教学工作改革的角度出发,探讨了实践教学在生物工程特色人才培养中的重要作用;在实践教学的实验环节重新整合实验课程,实习环节加强实习基地建设,改革实习模式,注重创新创业能力培养,引导学生参与课外科研创新课题与创业活动.结果证明,以上改革有利于为生物工程专业培养出高素质、有特色的创新、创业型人才.%The important status of practice education in biological engineering talents training is discussed in this paper. The experiment courses system is reintegrated. Construction of ficldwork bases is enhanced, and practice mode is reformed. Innovation and entrepreneurial capacities of the students are improved, and they are introduced to participate in extracurricular research subjects and entrepreneurial actions. It is concluded that all of the reform steps above are beneficial to training high-quality, unique innovation and entrepreneurial bio-logical engineering talents..

  18. Engineering and Characterization of Peptides and Proteins at Surfaces and Interfaces: A Case Study in Surface-Sensitive Vibrational Spectroscopy.

    Science.gov (United States)

    Ding, Bei; Jasensky, Joshua; Li, Yaoxin; Chen, Zhan

    2016-06-21

    Understanding molecular structures of interfacial peptides and proteins impacts many research fields by guiding the advancement of biocompatible materials, new and improved marine antifouling coatings, ultrasensitive and highly specific biosensors and biochips, therapies for diseases related to protein amyloid formation, and knowledge on mechanisms for various membrane proteins and their interactions with ligands. Developing methods for measuring such unique systems, as well as elucidating the structure and function relationship of such biomolecules, has been the goal of our lab at the University of Michigan. We have made substantial progress to develop sum frequency generation (SFG) vibrational spectroscopy into a powerful technique to study interfacial peptides and proteins, which lays a foundation to obtain unique and valuable insights when using SFG to probe various biologically relevant systems at the solid/liquid interface in situ in real time. One highlighting feature of this Account is the demonstration of the power of combining SFG with other techniques and methods such as ATR-FTIR, surface engineering, MD simulation, liquid crystal sensing, and isotope labeling in order to study peptides and proteins at interfaces. It is necessary to emphasize that SFG plays a major role in these studies, while other techniques and methods are supplemental. The central role of SFG is to provide critical information on interfacial peptide and protein structure (e.g., conformation and orientation) in order to elucidate how surface engineering (e.g., to vary the structure) can ultimately affect surface function (e.g., to optimize the activity). This Account focuses on the most significant recent progress in research on interfacial peptides and proteins carried out by our group including (1) the development of SFG analysis methods to determine orientations of regular as well as disrupted secondary structures, and the successful demonstration and application of an isotope

  19. Improving Efficiency, Extending the Maximum Load Limit and Characterizing the Control-related Problems Associated with Higher Loads in a 6-Cylinder Heavy-duty Natural gas Engine

    OpenAIRE

    Kaiadi, Mehrzad; Tunestål, Per; Johansson, Bengt

    2010-01-01

    High EGR rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark ignition Natural Gas engines. With stoichiometric conditions a three way catalyst can be used which means that regulated emissions can be kept at very low levels. Most of the heavy duty NG engines are diesel engines which are converted for SI operation. These engine's components are in common with the diesel-engine which put limits on higher exh...

  20. Characterization of mechanical and biological properties of 3-D scaffolds reinforced with zinc oxide for bone tissue engineering.

    Science.gov (United States)

    Feng, Pei; Wei, Pingpin; Shuai, Cijun; Peng, Shuping

    2014-01-01

    A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP) scaffolds via selective laser sintering (SLS). We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO). Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam(1/2), and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF), indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially.

  1. Characterization of mechanical and biological properties of 3-D scaffolds reinforced with zinc oxide for bone tissue engineering.

    Directory of Open Access Journals (Sweden)

    Pei Feng

    Full Text Available A scaffold for bone tissue engineering should have highly interconnected porous structure, appropriate mechanical and biological properties. In this work, we fabricated well-interconnected porous β-tricalcium phosphate (β-TCP scaffolds via selective laser sintering (SLS. We found that the mechanical and biological properties of the scaffolds were improved by doping of zinc oxide (ZnO. Our data showed that the fracture toughness increased from 1.09 to 1.40 MPam(1/2, and the compressive strength increased from 3.01 to 17.89 MPa when the content of ZnO increased from 0 to 2.5 wt%. It is hypothesized that the increase of ZnO would lead to a reduction in grain size and an increase in density of the strut. However, the fracture toughness and compressive strength decreased with further increasing of ZnO content, which may be due to the sharp increase in grain size. The biocompatibility of the scaffolds was investigated by analyzing the adhesion and the morphology of human osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The scaffolds exhibited better and better ability to support cell attachment and proliferation when the content of ZnO increased from 0 to 2.5 wt%. Moreover, a bone like apatite layer formed on the surfaces of the scaffolds after incubation in simulated body fluid (SBF, indicating an ability of osteoinduction and osteoconduction. In summary, interconnected porous β-TCP scaffolds doped with ZnO were successfully fabricated and revealed good mechanical and biological properties, which may be used for bone repair and replacement potentially.

  2. Inferring Ancient Technology and Practices of the Elite Maya Kingship Through the Application of Materials Engineering Characterization Modalities

    Science.gov (United States)

    Cheung, Kristina Alyssa

    This project focuses on the characterization of materials from burial offerings and painted decoration in a royal Maya tomb at El Zotz, Guatemala, and their association with mortuary rituals. Archaeological findings included vessels, jade masks, organic materials (wood, cord, and textiles), specular hematite cubes, shells with powdered cinnabar, green (malachite) painted stucco assumed to have decorated the wooden bier where the king was resting, and caches of lip-to-lip Aguila Orange bowls containing human phalanges. This paper describes findings from non-invasive and non-destructive analytical techniques including XRF, VPSEM-EDS, and XRD, emphasizing the potential of these combined technologies in the identification of organic and inorganic markers to infer burial customs. The nature and location of the findings, the evidence of pigment coloration on the bones employing hematite and cinnabar, and the indication of exposure of the bones to high temperatures suggest highly complex, even protracted mortuary practices of Maya elite.

  3. Synthesis and characterization of novel elastomeric poly(D,L-lactide urethane) maleate composites for bone tissue engineering.

    Science.gov (United States)

    Mercado-Pagán, Angel E; Kang, Yunqing; Ker, Dai Fei Elmer; Park, Sangwon; Yao, Jeffrey; Bishop, Julius; Yang, Yunzhi

    2013-10-01

    Here, we report the synthesis and characterization of a novel 4-arm poly(lactic acid urethane)-maleate (4PLAUMA) elastomer and its composites with nano-hydroxyapatite (nHA) as potential weight-bearing composite. The 4PLAUMA/nHA ratios of the composites were 1:3, 2:5, 1:2 and 1:1. FTIR and NMR characterization showed urethane and maleate units integrated into the PLA matrix. Energy dispersion and Auger electron spectroscopy confirmed homogeneous distribution of nHA in the polymer matrix. Maximum moduli and strength of the composites of 4PLAUMA/nHA, respectively, are 1973.31 ± 298.53 MPa and 78.10 ± 3.82 MPa for compression, 3630.46 ± 528.32 MPa and 6.23 ± 1.44 MPa for tension, 1810.42 ± 86.10 MPa and 13.00 ± 0.72 for bending, and 282.46 ± 24.91 MPa and 5.20 ± 0.85 MPa for torsion. The maximum tensile strains of the polymer and composites are in the range of 5% to 93%, and their maximum torsional strains vary from 0.26 to 0.90. The composites exhibited very slow degradation rates in aqueous solution, from approximately 50% mass remaining for the pure polymer to 75% mass remaining for composites with high nHA contents, after a period of 8 weeks. Increase in ceramic content increased mechanical properties, but decreased maximum strain, degradation rate, and swelling of the composites. Human bone marrow stem cells and human endothelial cells adhered and proliferated on 4PLAUMA films and degradation products of the composites showed little-to-no toxicity. These results demonstrate that novel 4-arm poly(lactic acid urethane)-maleate (4PLAUMA) elastomer and its nHA composites may have potential applications in regenerative medicine.

  4. Computer Jet-Engine-Monitoring System

    Science.gov (United States)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1992-01-01

    "Intelligent Computer Assistant for Engine Monitoring" (ICAEM), computer-based monitoring system intended to distill and display data on conditions of operation of two turbofan engines of F-18, is in preliminary state of development. System reduces burden on propulsion engineer by providing single display of summary information on statuses of engines and alerting engineer to anomalous conditions. Effective use of prior engine-monitoring system requires continuous attention to multiple displays.

  5. Computer Jet-Engine-Monitoring System

    Science.gov (United States)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1992-01-01

    "Intelligent Computer Assistant for Engine Monitoring" (ICAEM), computer-based monitoring system intended to distill and display data on conditions of operation of two turbofan engines of F-18, is in preliminary state of development. System reduces burden on propulsion engineer by providing single display of summary information on statuses of engines and alerting engineer to anomalous conditions. Effective use of prior engine-monitoring system requires continuous attention to multiple displays.

  6. U.S. Department of Energy FreedomCar & Vehicle Technologies Program CARB Executive Order Exemption Process for a Hydrogen-fueled Internal Combustion engine Vehicle -- Status Report

    Energy Technology Data Exchange (ETDEWEB)

    2008-04-01

    The CARB Executive Order Exemption Process for a Hydrogen-fueled Internal Combustion Engine Vehicle was undertaken to define the requirements to achieve a California Air Resource Board Executive Order for a hydrogenfueled vehicle retrofit kit. A 2005 to 2006 General Motors Company Sierra/Chevrolet Silverado 1500HD pickup was assumed to be the build-from vehicle for the retrofit kit. The emissions demonstration was determined not to pose a significant hurdle due to the non-hydrocarbon-based fuel and lean-burn operation. However, significant work was determined to be necessary for Onboard Diagnostics Level II compliance. Therefore, it is recommended that an Experimental Permit be obtained from the California Air Resource Board to license and operate the vehicles for the durability of the demonstration in support of preparing a fully compliant and certifiable package that can be submitted.

  7. [Relation of actual nutritional characteristics to the health status of retirees and persons of preretirement age employed in mechanical engineering production].

    Science.gov (United States)

    Grigorov, Iu G; Kozlovskaia, S G; Semes'ko, T M; Medovar, B Ia

    1988-01-01

    Actual nutrition and health state were investigated in 406 males of pre-pension and pension age (40-70 years) engaged in physical work (III category of difficulty) at an engineering plant. The chemical composition of their food was evaluated with respect to 74 chemical elements. The state of the workers' health was evaluated by the data obtained from the registers kept at the Plant medical unit. A relationship has been established between the character of the actual nutrition and the presence of an age-dependent disease, as well as the role of certain nutrients in the development of this or that disease in different age periods. A conclusion has been made on the necessity of the development of differential physiological requirements in the nutrients and energy for elder subjects engaged in the social industry, and inclusion of the rational nutrition into the complex of measures for prevention of age-dependent diseases.

  8. Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species

    Science.gov (United States)

    Prospere, Kurt; McLaren, Kurt P.; Wilson, Byron

    2016-10-01

    The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.

  9. Molecular characterization of HOXC8 gene and methylation status analysis of its exon 1 associated with the length of cashmere fiber in Liaoning cashmere goat.

    Science.gov (United States)

    Bai, Wen L; Wang, Jiao J; Yin, Rong H; Dang, Yun L; Wang, Ze Y; Zhu, Yu B; Cong, Yu Y; Deng, Liang; Guo, Dan; Wang, Shi Q; Yang, Shu H; Xue, Hui L

    2017-02-01

    Homeobox protein Hox-C8 (HOXC8) is a member of Hox family. It is expressed in the dermal papilla of the skin and is thought to be associated with the hair inductive capacity of dermal papilla cells. In the present study, we isolated and characterized a full-length open reading frame of HOXC8 cDNA from the skin tissue of Liaoning cashmere goat, as well as, established a phylogenetic relationship of goat HOXC8 with that of other species. Also, we investigated the effect of methylation status of HOXC8 exon 1 at anagen secondary hair follicle on the cashmere fiber traits in Liaoning cashmere goat. The sequence analysis indicated that the obtained cDNA was 1134-bp in length containing a complete ORF of 729-bp. It encoded a peptide of 242 amino acid residues in length. The structural analysis indicated that goat HOXC8 contained a typical homeobox domain. The phylogenetic analysis revealed that Capra hircus HOXC8 had a closer genetic relationship with that of Ovis aries, followed by Bos Taurus and Bubalus bubalis. The methylation analysis suggested that the methylation degree of HOXC8 exon 1 in anagen secondary hair follicle might be involved in regulating the growth of cashmere fiber in Liaoning cashmere goat. Our results provide new evidence for understanding the molecular structural and evolutionary characteristics of HOXC8 in Liaoning cashmere goat, as well as, for further insight into the role of methylation degree of HOXC8 exon 1 regulates the growth of cashmere fiber in goat.

  10. Characterizing the Status (Disturbed, Hybrid or Novel) of Swamp Forest Fragments in a Caribbean Ramsar Wetland: The Impact of Anthropogenic Degradation and Invasive Plant Species.

    Science.gov (United States)

    Prospere, Kurt; McLaren, Kurt P; Wilson, Byron

    2016-10-01

    The last remaining Amazonian-type swamp forest fragments in Black River Lower Morass, Jamaica, have been subjected to a myriad of anthropogenic disturbances, compounded by the establishment and spread of several invasive plant species. We established 44 permanent sample plots (covering 3.92 ha) across 10 of these swamp forest fragments and sampled all non-woody plants and all trees ≥2 cm DBH found in the plots. These data were used to (1) identify thresholds of hybridity and novelty, (2) derive several diversity and structural descriptors used to characterize the swamp forest fragments and (3) identify possible indicators of anthropogenic degradation. These were incorporated into a framework and used to determine the status of the swamp forest fragments so that appropriate management and conservation measures can be implemented. We recorded 43 woody plant species (9 endemic, 28 native and 4 non-native) and 21 non-tree species. The composition and structure of all the patches differed significantly due to the impact of the herbaceous invasive plant Alpinia allughas, the presence and diversity of other non-native plants, and differing intensities of anthropogenic disturbance (e.g., burning, cutting and harvesting of non-timber forest products). We ranked forest patches along a continuum representing deviations from a historical proxy (least disturbed) swamp forest to those with dramatically altered structural and floristic attributes (=novel swamp forests). Only one fragment overrun with A. allughas was classified as novel. If effective conservation and management does not come to the BRLM, the remaining swamp forest fragments appear doomed to further degradation and will soon disappear altogether.

  11. Retention of phosphorous ions on natural and engineered waste pumice: Characterization, equilibrium, competing ions, regeneration, kinetic, equilibrium and thermodynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Karimaian, Kamal Aldin [Department of Environmental Health Engineering, Faculty of Health, Kurdistan University of Medical Sciences, Sannandaj (Iran, Islamic Republic of); Amrane, Abdeltif [Ecole Nationale Supérieure de Chimie de Rennes, Université Rennes 1, CNRS, UMR 6226, Avenue du Général Leclerc, CS 50837, 35708 Rennes Cedex 7 (France); Kazemian, Hossein [Department of Chemical and Biochemical Engineering, Western University, London, ON, Canada N6A 5B9 (Canada); Panahi, Reza [Department of Biotechnology, Faculty of Chemical Engineering, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Zarrabi, Mansur, E-mail: mansor62@gmail.com [Department of Environmental Health Engineering, Faculty of Health, Alborz University of Medical Sciences, Karaj (Iran, Islamic Republic of)

    2013-11-01

    Natural and Mg{sup 2+} modified pumice were used for the removal of phosphorous. The adsorbents were characterized using XRF, XRD, SEM and FTIR instrumental techniques. In the optimal conditions, namely at equilibrium time (30 min), for a phosphorus concentration of 15 mg/L and pH 6, 69 and 97% phosphorus removals were achieved using 10 g/L of natural and modified pumice adsorbents, respectively. Maximum adsorption capacities were 11.88 and 17.71 mg/g by natural and modified pumice, respectively. Pseudo-second order kinetic model was the most relevant to describe the kinetic of phosphorus adsorption. External mass transfer coefficient decreased for increasing phosphorous concentration and film diffusion was found to be the rate-controlling step. Only a very low dissolution of the adsorbent was observed, leading to a low increase in conductivity and turbidity. Removal efficiency decreased for increasing ionic strength. It also decreased in the presence of competing ions; however modified pumice remained effective, since 67% of phosphorus was removed, versus only 17% for the natural pumice. The efficiency of the modified pumice was confirmed during the regeneration tests, since 96% regeneration yield was obtained after 510 min experiment, while only 22% was observed for the raw pumice.

  12. Characterization and enzymatic hydrolysis of wood from transgenic Pinus taeda engineered with syringyl lignin or reduced lignin content

    Energy Technology Data Exchange (ETDEWEB)

    Edmunds, Charles W.; Peralta, Perry; Kelley, Stephen S.; Chiang, Vincent L.; Sharma-Shivappa, Ratna R.; Davis, Mark F.; Harman-Ware, Anne E.; Sykes, Robert W.; Gjersing, Erica; Cunningham, Michael W.; Rottmann, William; Miller, Zachary D.; Peszlen, Ilona

    2017-02-22

    Softwood is an abundant resource; however, currently its utilization for bioconversion to obtain platform sugars is limited. Pinus taeda trees which were genetically modified to either produce S lignin or to decrease lignin content were characterized with a suite of analytic techniques. Syringyl lignin was visualized in the secondary xylem of one genetic line with Maule staining. Solid-state nuclear magnetic resonance identified the S lignin units were coupled into the lignin through ..beta..-O-4 linkages, and thioacidolysis measured approximately 13% S lignin content in the same sample. Reductions of the lignin of as much as 33% were observed in the transgenics. To better understand how these modifications affect bioconversion, their amenability to hot water and dilute acid pretreatments and enzymatic hydrolysis was evaluated. Lignin reductions resulted in 1.9-3.2-fold increases in glucose release compared to the control. However, no apparent benefit was observed by S lignin incorporation at the concentrations reported in this study. These results highlight the potential for softwood cell wall properties to be improved for bioenergy/biochemical applications.

  13. Engineered phages for electronics.

    Science.gov (United States)

    Cui, Yue

    2016-11-15

    Phages are traditionally widely studied in biology and chemistry. In recent years, engineered phages have attracted significant attentions for functionalization or construction of electronic devices, due to their specific binding, catalytic, nucleating or electronic properties. To apply the engineered phages in electronics, these are a number of interesting questions: how to engineer phages for electronics? How are the engineered phages characterized? How to assemble materials with engineered phages? How are the engineered phages micro or nanopatterned? What are the strategies to construct electronics devices with engineered phages? This review will highlight the early attempts to address these questions and explore the fundamental and practical aspects of engineered phages in electronics, including the approaches for selection or expression of specific peptides on phage coat proteins, characterization of engineered phages in electronics, assembly of electronic materials, patterning of engineered phages, and construction of electronic devices. It provides the methodologies and opens up ex-cit-ing op-por-tu-ni-ties for the development of a variety of new electronic materials and devices based on engineered phages for future applications.

  14. Integrated geological and engineering characterization of an Upper Permian, carbonate reservoir, South Cowden unit, Ector County Texas -- a work in progress

    Energy Technology Data Exchange (ETDEWEB)

    Gerard, M.G.; Johnson, J.V.; Snow, S.C. [Phillips Petroleum Company, Odessa, TX (United States)] [and others

    1995-09-01

    South Cowden Unit, located on the eastern margin of the Central Basin Platform, has produced 35 million barrels of oil since initial development in the late 1940`s. The Unit, under waterflood since 1965, has been proposed for a CO{sub 2} flood using horizontal injection wells. A team of geologists and engineers was formed to characterize the reservoir. The early and complete integration of geologic and engineering work has resulted in a detailed reservoir description to be used in reservoir simulation. Regional mapping and 3D seismic data indicate that sediments within the reservoir interval were draped over a paleohigh resulting in an unfaulted, anticlinal-like structure. A field-wide stratigraphic framework was developed using two to four-foot thick, gamma-ray log markers which correspond to low permeability, sandy dolomite layers recognized in core. These log correlations indicate fairly simple and uniform structure and stratigraphy. The gamma-ray markers delineate four zones within the 150 foot reservoir interval. Rocks composing these zones are extensively dolomitized and display a complex color mottling. This mottling is related most likely to bioturbation of carbonate sediments in a shallow, subtidal marine environment. Extensive and interconnected bioturbated areas have core analysis porosities averaging approximately 20% and permeabilities generally ranging from 2 to 350 md. The intervening, nonburrowed and unstained areas have porosities averaging 5% and permeabilities typically ranging form 0.01 to 2 md. Variations in the quality and thickness of the mottled facies are major parameters controlling oil recovery. A belt of better reservoir-quality rock runs roughly parallel to structure and results in an area of higher cumulative oil production. Good waterflood response and uniform pressure distribution indicate continuity of the pay zones within this belt.

  15. Characterization of novel akermanite:poly-ϵ-caprolactone scaffolds for human adipose-derived stem cells bone tissue engineering.

    Science.gov (United States)

    Zanetti, A S; McCandless, G T; Chan, J Y; Gimble, J M; Hayes, D J

    2015-04-01

    In this study, three different akermanite:poly-ϵ-caprolactone (PCL) composite scaffolds (wt%: 75:25, 50:50, 25:75) were characterized in terms of structure, compression strength, degradation rate and in vitro biocompatibility to human adipose-derived stem cells (hASC). Pure ceramic scaffolds [CellCeram™, custom-made, 40:60 wt%; β-tricalcium phosphate (β-TCP):hydroxyapatite (HA); and akermanite] and PCL scaffolds served as experimental controls. Compared to ceramic scaffolds, the authors hypothesized that optimal akermanite:PCL composites would have improved compression strength and comparable biocompatibility to hASC. Electron microscopy analysis revealed that PCL-containing scaffolds had the highest porosity but CellCeram™ had the greatest pore size. In general, compression strength in PCL-containing scaffolds was greater than in ceramic scaffolds. PCL-containing scaffolds were also more stable in culture than ceramic scaffolds. Nonetheless, mass losses after 21 days were observed in all scaffold types. Reduced hASC metabolic activity and increased cell detachment were observed after acute exposure to akermanite:PCL extracts (wt%: 75:25, 50:50). Among the PCL-containing scaffolds, hASC cultured for 21 days on akermanite:PCL (wt%: 75:25) discs displayed the highest viability, increased expression of osteogenic markers (alkaline phosphatase and osteocalcin) and lowest IL-6 expression. Together, the results indicate that akermanite:PCL composites may have appropriate mechanical and biocompatibility properties for use as bone tissue scaffolds.

  16. Aliphatic amine cured PDMS–epoxy interpenetrating network system for high performance engineering applications—Development and characterization

    Indian Academy of Sciences (India)

    T V Thanikai Velan; I Mohammed Bilal

    2000-10-01

    A siliconized epoxy interpenetrating network (IPN) was synthesized from commercially available DGEBA epoxy resin GY250 (Ciba-Geigy, epoxy equivalent = 182–192, viscosity = 9000–12000 cP) and hydroxyl terminated polydimethylsiloxane (PDMS). PDMS and GY250 were thoroughly mixed at 30°C to get the prepolymer. Stoichiometric amounts of PDMS–epoxy prepolymer, -aminopropyltriethoxysilane, aliphatic amine curing agent (HY951), and dibutyltindilaurate catalyst, were thoroughly mixed and cast in a mould after evacuating the entrapped air. The cured material was then taken out and post cured at 70°C for 10 h. IPN was characterized by FTIR spectroscopy, SEM, DSC, TGA and viscosity measurements. Incorporation of PDMS in the epoxy matrix increased the viscosity and lowered the exotherm and pot-life. PDMS in IPN increased , heat-distortion temperature and reduced the percentage weight loss with increase in temperature. Incorporation of PDMS drastically reduced the tensile and flexural strengths and hardness. By reducing the tensile and flexural modulus, the siloxane moiety effectively reduced the internal stress of IPN thereby improving its impact strength and percentage elongation. PDMS increased the electric potential gradient of IPN to withstand without breakdown. An increase in the tracking index and arc resistance of IPN were observed, because of the presence of Si–O–Si, which minimized the possibility of forming carbonized path. Volume and surface resistivities of IPN also increased with the incorporation of PDMS. The siliconized epoxy IPN, with better impact and thermal resistance, may be used in automobile and aerospace applications to withstand high temperature, and mechanical stress. The PDMS–epoxy IPN may be used for encapsulation, high temperature and high voltage application due to their low shrinkage and lesser internal stress. With the improved electrical characteristics, IPN may be used for high performance electrical insulation, insulator housings

  17. R and D status and requirements for PIE in the fields of the HTGR fuel and the innovative basic research on High-Temperature Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Sawa, Kazuhiro; Tobita, Tsutomu; Sumita, Junya [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Ishihara, Masahiro; Hayashi, Kimio; Hoshiya, Taiji; Sekino, Hajime; Ooeda, Etsurou

    1999-09-01

    The High Temperature Engineering Test Reactor (HTTR), which is the first high temperature gas-cooled reactor (HTGR) in Japan, achieved its first criticality in November 1998 at the Oarai Research Establishment of the Japan Atomic Energy Research Institute (JAERI). In the field of HTGR fuel development, JAERI will proceed research and development (R and D) works by the following steps: (STEP-1) confirmation of irradiation performance of the first-loading fuel of the HTTR, (STEP-2) study on irradiation performance of high burnup SiC-coated fuel particle and (STEP-3) development of ZrC-coated fuel particle. Requirements for post-irradiation examination (PIE) are different for each R and D step. In STEP-1, firstly, hot cells will be prepared in the HTTR reactor building to handle spent fuels. In parallel, general equipments such as those for deconsolidation of fuel compacts and for handling coated fuel particles will be installed in the Hot Laboratory at Oarai. In STEP-2, precise PIE techniques, for example, Raman spectroscopy for measurement of stress on irradiated SiC layer, will be investigated. In STEP-3, new PIE techniques should be developed to investigate irradiation behavior of ZrC-coated particle. In the field of the innovative basic research on high-temperature engineering, some preliminary tests have been made on the research areas of (1) new materials development, (2) fusion technology, (3) radiation chemistry and (4) high-temperature in-core instrumentation. Requirements for PIE are under investigation, in particular in the field of the new materials development. Besides more general apparatuses including transmission electron microscopy (TEM), some special apparatuses such as an electron spin resonance (ESR) spectrometer, a specific resistance/Hall coefficient measuring system and a differential scanning calorimeter (DSC) are planned to install in the Hot Laboratory at Oarai. Acquisition of advanced knowledge on the irradiation behavior is expected in

  18. The Status and Construction Plan of Highway Engineering Cost Major%公路工程造价专业现状及建设规划

    Institute of Scientific and Technical Information of China (English)

    王险峰

    2011-01-01

    There are 12 main problems in the highway engineering construction in each phase of the project budget preparation and investment control.Cost control measures in project decision-making stage(well preparation of project decision-making,do the project feasibility study report,compiled thorough and careful investment estimate and scheme optimization)and cost control measures in design stage(strengthen the coordination and supervision of the design process,and professional design personnel with planning construction organization and design scheme,strengthen the quota design and control of the project cost) are presented in view of the existing problems.The suggestions for planning and construction of project cost standardized management system in the aspects of the general ideas,standardized management and the technical route to achieve the purpose of engineering cost control.%针对在公路工程建设各阶段概预算编制和投资控制中存在的12个主要问题,从工程设计角度进行分析,对存在的问题提出项目决策阶段造价控制的对策(做好项目决策前的准备工作、认真做好项目可行性研究报告、全面细致编制投资估算、方案优化)和设计阶段造价控制的对策(加强设计过程的协调与监督、与专业设计人员配合编制施工组织设计方案、加强限额设计控制工程造价)。并对工程造价标准化管理体系的规划建设,从总体思路、标准化管理、技术路线提出建议,达到控制工程造价的目的。

  19. 西吉县淤地坝工程建设现状与分析%Status and Analysis of Engineering Construction of Silt Dams in Xiji County

    Institute of Scientific and Technical Information of China (English)

    李国相

    2012-01-01

    There are 26 silt dams of dilapidated silt dam reinforcement and repair engineering in Xiji County, control area of 237.05km2, total storage capacity of 35,332,900 m3, choked with silt of 12,558,100. m3 and choked with soil of 180.28hm2; The construction of silt dams dredges regional traffic to a certain degree, which solves the problem of difficulty in drinking water for local people and develops irrigated land, laying a solid foundation for the local people to become rich.%西吉县病险淤地坝加固维修工程加固维修的淤地坝有26座,控制面积237.05km2,总库容3533.29万m3,已淤库容1255.81万m3,已淤地180.28hm2;这些淤地坝的建设,在一定程度上疏通了区域内的交通,解决当地群众的吃水难问题,发展水浇地,为当地群众脱贫致富奠定了坚实的基础.

  20. Characterization of the microheterogeneities of PIXY321, a genetically engineered granulocyte-macrophage colony-stimulating factor/interleukin-3 fusion protein expressed in yeast.

    Science.gov (United States)

    Balland, A; Krasts, D A; Hoch, K L; Gerhart, M J; Stremler, K E; Waugh, S M

    1998-02-01

    PIXY321, a human cytokine analog genetically engineered by the fusion of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), was expressed in yeast under the control of the alcohol dehydrogenase 2 (ADH2) promoter and the alpha-mating factor expression system. To provide the material necessary for the evaluation of PIXY321 in clinical trials, the production was scaled up to the 1200-1 scale and the PIXY321 molecule isolated by four successive steps of ion-exchange chromatography. Multiple heterogeneities, due to the presence of different patterns of glycosylation as well as multiple amino acid sequences at both N and C termini, were characterized on the purified molecule using complementary analytical techniques including electrophoresis, liquid chromatography and electrospray mass spectrometry. Four different N-terminal sequences were identified but simplified to a reproducible ratio of two sequences, the mature form and a form starting at Ala3, by adjustment of the process conditions. Molecules lacking 1-6 residues at the C-terminus were identified and their relative frequencies quantified. Amino acid modifications, such as three oxidized Met residues at positions 79, 141 and 187 and one deamidated Asn residue at position 176, were detected at low level. Microheterogeneities in glycosylation were characterized on four different sites, one located in the GM-CSF portion and three in the IL-3 portion of the molecule. The sites were shown to be differentially occupied and to carry 0-10 mannose residues according to their location in the sequence. Precise measurement of the heterogeneities at the molecular level were used to tune the process conditions and ensure reproducibility of the clinical product between lots.

  1. Engineering Encounters: Reverse Engineering

    Science.gov (United States)

    McGowan, Veronica Cassone; Ventura, Marcia; Bell, Philip

    2017-01-01

    This column presents ideas and techniques to enhance your science teaching. This month's issue shares information on how students' everyday experiences can support science learning through engineering design. In this article, the authors outline a reverse-engineering model of instruction and describe one example of how it looked in our fifth-grade…

  2. ENGINEERING BULLETIN: SUPERCRITICAL WATER OXIDATION

    Science.gov (United States)

    This engineering bulletin presents a description and status of supercritical water oxidation technology, a summary of recent performance tests, and the current applicability of this emerging technology. This information is provided to assist remedial project managers, contractors...

  3. Mesenchymal stem cells: Identification, phenotypic characterization, biological properties and potential for regenerative medicine through biomaterial micro-engineering of their niche.

    Science.gov (United States)

    Kobolak, Julianna; Dinnyes, Andras; Memic, Adnan; Khademhosseini, Ali; Mobasheri, Ali

    2016-04-15

    Mesenchymal stem cells (MSCs) are multipotent stem cells. Although they were originally identified in bone marrow and described as 'marrow stromal cells', they have since been identified in many other anatomical locations in the body. MSCs can be isolated from bone marrow, adipose tissue, umbilical cord and other tissues but the richest tissue source of MSCs is fat. Since they are adherent to plastic, they may be expanded in vitro. MSCs have a distinct morphology and express a specific set of CD (cluster of differentiation) molecules. The phenotypic pattern for the identification of MSCs cells requires expression of CD73, CD90, and CD105 and lack of CD34, CD45, and HLA-DR antigens. Under appropriate micro-environmental conditions MSCs can proliferate and give rise to other cell types. Therefore, they are ideally suited for the treatment of systemic inflammatory and autoimmune conditions. They have also been implicated as key players in regenerating injured tissue following injury and trauma. MSC populations isolated from adipose tissue may also contain regulatory T (Treg) cells, which have the capacity for modulating the immune system. The immunoregulatory and regenerative properties of MSCs make them ideal for use as therapeutic agents in vivo. In this paper we review the literature on the identification, phenotypic characterization and biological properties of MSCs and discuss their potential for applications in cell therapy and regenerative medicine. We also discuss strategies for biomaterial micro-engineering of the stem cell niche.

  4. Structural and biophysical characterization of an epitope-specific engineered Fab fragment and complexation with membrane proteins: implications for co-crystallization.

    Science.gov (United States)

    Johnson, Jennifer L; Entzminger, Kevin C; Hyun, Jeongmin; Kalyoncu, Sibel; Heaner, David P; Morales, Ivan A; Sheppard, Aly; Gumbart, James C; Maynard, Jennifer A; Lieberman, Raquel L

    2015-04-01

    Crystallization chaperones are attracting increasing interest as a route to crystal growth and structure elucidation of difficult targets such as membrane proteins. While strategies to date have typically employed protein-specific chaperones, a peptide-specific chaperone to crystallize multiple cognate peptide epitope-containing client proteins is envisioned. This would eliminate the target-specific chaperone-production step and streamline the co-crystallization process. Previously, protein engineering and directed evolution were used to generate a single-chain variable (scFv) antibody fragment with affinity for the peptide sequence EYMPME (scFv/EE). This report details the conversion of scFv/EE to an anti-EE Fab format (Fab/EE) followed by its biophysical characterization. The addition of constant chains increased the overall stability and had a negligible impact on the antigen affinity. The 2.0 Å resolution crystal structure of Fab/EE reveals contacts with larger surface areas than those of scFv/EE. Surface plasmon resonance, an enzyme-linked immunosorbent assay, and size-exclusion chromatography were used to assess Fab/EE binding to EE-tagged soluble and membrane test proteins: namely, the β-barrel outer membrane protein intimin and α-helical A2a G protein-coupled receptor (A2aR). Molecular-dynamics simulation of the intimin constructs with and without Fab/EE provides insight into the energetic complexities of the co-crystallization approach.

  5. Additive Manufacturing of IN100 Superalloy Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair: Process Development, Modeling, Microstructural Characterization, and Process Control

    Science.gov (United States)

    Acharya, Ranadip; Das, Suman

    2015-09-01

    This article describes additive manufacturing (AM) of IN100, a high gamma-prime nickel-based superalloy, through scanning laser epitaxy (SLE), aimed at the creation of thick deposits onto like-chemistry substrates for enabling repair of turbine engine hot-section components. SLE is a metal powder bed-based laser AM technology developed for nickel-base superalloys with equiaxed, directionally solidified, and single-crystal microstructural morphologies. Here, we combine process modeling, statistical design-of-experiments (DoE), and microstructural characterization to demonstrate fully metallurgically bonded, crack-free and dense deposits exceeding 1000 μm of SLE-processed IN100 powder onto IN100 cast substrates produced in a single pass. A combined thermal-fluid flow-solidification model of the SLE process compliments DoE-based process development. A customized quantitative metallography technique analyzes digital cross-sectional micrographs and extracts various microstructural parameters, enabling process model validation and process parameter optimization. Microindentation measurements show an increase in the hardness by 10 pct in the deposit region compared to the cast substrate due to microstructural refinement. The results illustrate one of the very few successes reported for the crack-free deposition of IN100, a notoriously "non-weldable" hot-section alloy, thus establishing the potential of SLE as an AM method suitable for hot-section component repair and for future new-make components in high gamma-prime containing crack-prone nickel-based superalloys.

  6. Microfluidics and microbial engineering.

    Science.gov (United States)

    Kou, Songzi; Cheng, Danhui; Sun, Fei; Hsing, I-Ming

    2016-02-01

    The combination of microbial engineering and microfluidics is synergistic in nature. For example, microfluidics is benefiting from the outcome of microbial engineering and many reported point-of-care microfluidic devices employ engineered microbes as functional parts for the microsystems. In addition, microbial engineering is facilitated by various microfluidic techniques, due to their inherent strength in high-throughput screening and miniaturization. In this review article, we firstly examine the applications of engineered microbes for toxicity detection, biosensing, and motion generation in microfluidic platforms. Secondly, we look into how microfluidic technologies facilitate the upstream and downstream processes of microbial engineering, including DNA recombination, transformation, target microbe selection, mutant characterization, and microbial function analysis. Thirdly, we highlight an emerging concept in microbial engineering, namely, microbial consortium engineering, where the behavior of a multicultural microbial community rather than that of a single cell/species is delineated. Integrating the disciplines of microfluidics and microbial engineering opens up many new opportunities, for example in diagnostics, engineering of microbial motors, development of portable devices for genetics, high throughput characterization of genetic mutants, isolation and identification of rare/unculturable microbial species, single-cell analysis with high spatio-temporal resolution, and exploration of natural microbial communities.

  7. Nuclear engineering vocabulary

    Energy Technology Data Exchange (ETDEWEB)

    Dumont, X. [FRAMATOME, Dept. Corporate R and D, 92 - Paris-La-Defence (France); Andrieux, C. [CEA Saclay, Direction des Technologies de l' Information, DTI, 91 - Gif sur Yvette (France)

    2001-07-01

    The members of the CSTNIN - the Special Commission for Nuclear Engineering Terminology and Neology - have just produced a Nuclear Engineering Vocabulary, published by SFEN. A 120-page document which, to date, includes 400 nuclear engineering terms or expressions. For each term or expression, this Glossary gives: the primary and secondary subject field in which it is applied, a possible abbreviation, its definition, a synonym if appropriate, any relevant comments, any associated word(s), the English equivalent, its status on the date of publication of the Glossary. (author)

  8. Layered Systems Engineering Engines

    Science.gov (United States)

    Breidenthal, Julian C.; Overman, Marvin J.

    2009-01-01

    A notation is described for depicting the relationships between multiple, contemporaneous systems engineering efforts undertaken within a multi-layer system-of-systems hierarchy. We combined the concepts of remoteness of activity from the end customer, depiction of activity on a timeline, and data flow to create a new kind of diagram which we call a "Layered Vee Diagram." This notation is an advance over previous notations because it is able to be simultaneously precise about activity, level of granularity, product exchanges, and timing; these advances provide systems engineering managers a significantly improved ability to express and understand the relationships between many systems engineering efforts. Using the new notation, we obtain a key insight into the relationship between project duration and the strategy selected for chaining the systems engineering effort between layers, as well as insights into the costs, opportunities, and risks associated with alternate chaining strategies.

  9. 应用技术型高校工科专业创业教育的现状及对策研究%The status quo and countermeasures of application technology college’s engineering professional entrepreneurship education

    Institute of Scientific and Technical Information of China (English)

    刘雅娴

    2014-01-01

    面临日益严峻的大学生就业形势,应用技术型本科高校如何搞好本科教育的同时,做到“出口畅”,除了传统的就业方式,如考研、找工作、出国外,做好大学生创业教育,很有必要的同时,也是难点,本文分析应用技术型高校的工科专业创业教育的现状,并提出了一些对策。%Facing increasingly severe employment situation, how to improve technology application undergraduate course colleges and universities undergraduate education? In addition to the traditional way of employment, such as one's deceased father grind, looking for a job, a foreign, do a good job in college students' entrepreneurship education, it is necessary, but it is also the difficulty, this paper analyzes the status quo of application technology college of engineering professional entrepreneurship education, and puts forward some countermeasures.

  10. Internal combustion piston engines

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C.L.

    1977-07-01

    Current worldwide production of internal combustion piston engines includes many diversified types of designs and a very broad range of sizes. Engine sizes range from a few horsepower in small mobile units to over 40,000 brake horsepower in large stationary and marine units. The key characteristics of internal combustion piston engines considered appropriate for use as prime movers in Integrated Community Energy Systems (ICES) are evaluated. The categories of engines considered include spark-ignition gas engines, compression-ignition oil (diesel) engines, and dual-fuel engines. The engines are evaluated with respect to full-load and part-load performance characteristics, reliability, environmental concerns, estimated 1976 cost data, and current and future status of development. The largest internal combustion piston engines manufactured in the United States range up to 13,540 rated brake horsepower. Future development efforts are anticipated to result in a 20 to 25% increase in brake horsepower without increase in or loss of weight, economy, reliability, or life expectancy, predicated on a simple extension of current development trends.

  11. Engineer Ethics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae Sik; Kim, Yeong Pil; Kim, Yeong Jin

    2003-03-15

    This book tells of engineer ethics such as basic understanding of engineer ethics with history of engineering as a occupation, definition of engineering and specialized job and engineering, engineer ethics as professional ethics, general principles of ethics and its limitation, ethical theory and application, technique to solve the ethical problems, responsibility, safety and danger, information engineer ethics, biotechnological ethics like artificial insemination, life reproduction, gene therapy and environmental ethics.

  12. Characterization of Engine Mount Elastomers

    Science.gov (United States)

    2005-02-01

    20 °C, varient grandement, car elles se situent entre 0,02 pour le caoutchouc naturel et 0,27, dans le cas de l’élastomère à base de copolymère...deux élastomères préparés au PSL résistent assez bien aux hydrocarbures. Toutefois, dans le cas d’un mélange de caoutchouc nitrile et de poly...de copolymère d’éthylène/acide acrylique constitue un produit de remplacement acceptable du caoutchouc naturel et du caoutchouc néoprène, dans les

  13. Detection, characterization and quantification of inorganic engineered nanomaterials: A review of techniques and methodological approaches for the analysis of complex samples

    Energy Technology Data Exchange (ETDEWEB)

    Laborda, Francisco, E-mail: flaborda@unizar.es; Bolea, Eduardo; Cepriá, Gemma; Gómez, María T.; Jiménez, María S.; Pérez-Arantegui, Josefina; Castillo, Juan R.

    2016-01-21

    The increasing demand of analytical information related to inorganic engineered nanomaterials requires the adaptation of existing techniques and methods, or the development of new ones. The challenge for the analytical sciences has been to consider the nanoparticles as a new sort of analytes, involving both chemical (composition, mass and number concentration) and physical information (e.g. size, shape, aggregation). Moreover, information about the species derived from the nanoparticles themselves and their transformations must also be supplied. Whereas techniques commonly used for nanoparticle characterization, such as light scattering techniques, show serious limitations when applied to complex samples, other well-established techniques, like electron microscopy and atomic spectrometry, can provide useful information in most cases. Furthermore, separation techniques, including flow field flow fractionation, capillary electrophoresis and hydrodynamic chromatography, are moving to the nano domain, mostly hyphenated to inductively coupled plasma mass spectrometry as element specific detector. Emerging techniques based on the detection of single nanoparticles by using ICP-MS, but also coulometry, are in their way to gain a position. Chemical sensors selective to nanoparticles are in their early stages, but they are very promising considering their portability and simplicity. Although the field is in continuous evolution, at this moment it is moving from proofs-of-concept in simple matrices to methods dealing with matrices of higher complexity and relevant analyte concentrations. To achieve this goal, sample preparation methods are essential to manage such complex situations. Apart from size fractionation methods, matrix digestion, extraction and concentration methods capable of preserving the nature of the nanoparticles are being developed. This review presents and discusses the state-of-the-art analytical techniques and sample preparation methods suitable for

  14. Detection, characterization and quantification of inorganic engineered nanomaterials: A review of techniques and methodological approaches for the analysis of complex samples.

    Science.gov (United States)

    Laborda, Francisco; Bolea, Eduardo; Cepriá, Gemma; Gómez, María T; Jiménez, María S; Pérez-Arantegui, Josefina; Castillo, Juan R

    2016-01-21

    The increasing demand of analytical information related to inorganic engineered nanomaterials requires the adaptation of existing techniques and methods, or the development of new ones. The challenge for the analytical sciences has been to consider the nanoparticles as a new sort of analytes, involving both chemical (composition, mass and number concentration) and physical information (e.g. size, shape, aggregation). Moreover, information about the species derived from the nanoparticles themselves and their transformations must also be supplied. Whereas techniques commonly used for nanoparticle characterization, such as light scattering techniques, show serious limitations when applied to complex samples, other well-established techniques, like electron microscopy and atomic spectrometry, can provide useful information in most cases. Furthermore, separation techniques, including flow field flow fractionation, capillary electrophoresis and hydrodynamic chromatography, are moving to the nano domain, mostly hyphenated to inductively coupled plasma mass spectrometry as element specific detector. Emerging techniques based on the detection of single nanoparticles by using ICP-MS, but also coulometry, are in their way to gain a position. Chemical sensors selective to nanoparticles are in their early stages, but they are very promising considering their portability and simplicity. Although the field is in continuous evolution, at this moment it is moving from proofs-of-concept in simple matrices to methods dealing with matrices of higher complexity and relevant analyte concentrations. To achieve this goal, sample preparation methods are essential to manage such complex situations. Apart from size fractionation methods, matrix digestion, extraction and concentration methods capable of preserving the nature of the nanoparticles are being developed. This review presents and discusses the state-of-the-art analytical techniques and sample preparation methods suitable for

  15. Characterization of Panax ginseng UDP-Glycosyltransferases Catalyzing Protopanaxatriol and Biosyntheses of Bioactive Ginsenosides F1 and Rh1 in Metabolically Engineered Yeasts.

    Science.gov (United States)

    Wei, Wei; Wang, Pingping; Wei, Yongjun; Liu, Qunfang; Yang, Chengshuai; Zhao, Guoping; Yue, Jianmin; Yan, Xing; Zhou, Zhihua

    2015-09-01

    Ginsenosides, the main pharmacologically active natural compounds in ginseng (Panax ginseng), are mostly the glycosylated products of protopanaxadiol (PPD) and protopanaxatriol (PPT). No uridine diphosphate glycosyltransferase (UGT), which catalyzes PPT to produce PPT-type ginsenosides, has yet been reported. Here, we show that UGTPg1, which has been demonstrated to regio-specifically glycosylate the C20-OH of PPD, also specifically glycosylates the C20-OH of PPT to produce bioactive ginsenoside F1. We report the characterization of four novel UGT genes isolated from P. ginseng, sharing high deduced amino acid identity (>84%) with UGTPg1. We demonstrate that UGTPg100 specifically glycosylates the C6-OH of PPT to produce bioactive ginsenoside Rh1, and UGTPg101 catalyzes PPT to produce F1, followed by the generation of ginsenoside Rg1 from F1. However, UGTPg102 and UGTPg103 were found to have no detectable activity on PPT. Through structural modeling and site-directed mutagenesis, we identified several key amino acids of these UGTs that may play important roles in determining their activities and substrate regio-specificities. Moreover, we constructed yeast recombinants to biosynthesize F1 and Rh1 by introducing the genetically engineered PPT-producing pathway and UGTPg1 or UGTPg100. Our study reveals the possible biosynthetic pathways of PPT-type ginsenosides in Panax plants, and provides a sound manufacturing approach for bioactive PPT-type ginsenosides in yeast via synthetic biology strategies. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  16. Engineering and design skills

    DEFF Research Database (Denmark)

    Schrøder, Anne Lise

    2006-01-01

    In various branches of society there is focus on the need for design skills and innovation potential as a means of communicating and handling constant change. In this context, the traditional idea of the engineer as a poly-technician inventing solutions by understanding the laws of nature...... concept of diagrammatic reasoning to some extent incarnates the very method of engineering and design. On this background, it is argued how the work field and techniques of the engineer and the engineering scientist could be characterized in a broader creative context of learning and communication....... This leads to considering the fundamental skills of the engineering practice as basic abilities to see the structures and dynamics of the world, to model it, and to create new solutions concerning practical as well as theoretical matters. Finally, it is assumed that the essence of engineering “bildung...

  17. Four Engineers...

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There are four engineers traveling in a car;a mechanical engineer,a chemical engi-neer,an electrical engineer and a comput-er engineer.The car breaks down.“Sounds to me as if the pistons have seized.We ll have to strip down the engine before we canget the car working again,”says the mechanical

  18. Chemical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions eXperiment (APEX) 1 to 3

    Science.gov (United States)

    This paper addresses the need for detailed chemical information on the fine particulate matter (PM2.5) generated by commercial aviation engines. The exhaust plumes of nine engine models were sampled during the three test campaigns of the Aircraft Particle Emissions eXperiment (AP...

  19. Physical characterization of the fine particle emissions from commercial aircraft engines during the Aircraft Particle Emissions Experiment (APEX) 1 to 3

    Science.gov (United States)

    The f1me particulate matter (PM) emissions from nine commercial aircraft engine models were determined by plume sampling during the three field campaigns of the Aircraft Particle Emissions Experiment (APEX). Ground-based measurements were made primarily at 30 m behind the engine ...

  20. Systems engineering: A problem of perception

    Energy Technology Data Exchange (ETDEWEB)

    Senglaub, M.

    1995-08-01

    The characterization of systems engineering as a discipline, process, procedure or a set of heuristics will have an impact on the implementation strategy, the training methodology, and operational environment. The systems engineering upgrade activities in the New Mexico Weapons Development Center and a search of systems engineering related information provides evidence of a degree of ambiguity in this characterization of systems engineering. A case is made in this article for systems engineering being the engineering discipline applied to the science of complexity. Implications of this characterization and some generic issues are delineated with the goal of providing an enterprise with a starting point for developing its business environment.

  1. Space Civil Engineering option - A progress report

    Science.gov (United States)

    Criswell, Marvin E.; Sadeh, Willy Z.

    1992-01-01

    Space Civil Engineering is an emerging engineering discipline that focuses on extending and expanding Civil Engineering to the development, operation, and maintenance of infrastructures on celestial bodies. Space Civil Engineering is presently being developed as a new discipline within the Department of Civil Engineering at Colorado State University and with support of the NASA Space Grant College Program. Academic programs geared toward creating Space Civil Engineering Options at both undergraduate and graduate levels are being formulated. Basic ideas and concepts and the current status of the curriculum in the Space Civil Engineering Option primarily at the undergraduate level are presented.

  2. Status epilepticus

    NARCIS (Netherlands)

    Hensiek, AE; Absalom, Anthony

    2006-01-01

    Status epilepticus is defined as epileptic activity that continues for more than 30 minutes as a single seizure or as recurrent seizures without inter-ictal return of consciousness. The seizure activity is usually classified as partial or generalized. Although status epilepticus is an uncommon admis

  3. Status epilepticus

    NARCIS (Netherlands)

    Hensiek, AE; Absalom, Anthony

    2006-01-01

    Status epilepticus is defined as epileptic activity that continues for more than 30 minutes as a single seizure or as recurrent seizures without inter-ictal return of consciousness. The seizure activity is usually classified as partial or generalized. Although status epilepticus is an uncommon admis

  4. Engineering and Software Engineering

    Science.gov (United States)

    Jackson, Michael

    The phrase ‘software engineering' has many meanings. One central meaning is the reliable development of dependable computer-based systems, especially those for critical applications. This is not a solved problem. Failures in software development have played a large part in many fatalities and in huge economic losses. While some of these failures may be attributable to programming errors in the narrowest sense—a program's failure to satisfy a given formal specification—there is good reason to think that most of them have other roots. These roots are located in the problem of software engineering rather than in the problem of program correctness. The famous 1968 conference was motivated by the belief that software development should be based on “the types of theoretical foundations and practical disciplines that are traditional in the established branches of engineering.” Yet after forty years of currency the phrase ‘software engineering' still denotes no more than a vague and largely unfulfilled aspiration. Two major causes of this disappointment are immediately clear. First, too many areas of software development are inadequately specialised, and consequently have not developed the repertoires of normal designs that are the indispensable basis of reliable engineering success. Second, the relationship between structural design and formal analytical techniques for software has rarely been one of fruitful synergy: too often it has defined a boundary between competing dogmas, at which mutual distrust and incomprehension deprive both sides of advantages that should be within their grasp. This paper discusses these causes and their effects. Whether the common practice of software development will eventually satisfy the broad aspiration of 1968 is hard to predict; but an understanding of past failure is surely a prerequisite of future success.

  5. Generation and characterization of diesel engine combustion emissions from petroleum diesel and soybean biodiesel fuels and application for inhalation exposure studies

    Science.gov (United States)

    Biodiesel made from the transesterification of plant- and anmal-derived oils is an important alternative fuel source for diesel engines. Although numerous studies have reported health effects associated with petroleum diesel emissions, information on biodiesel emissions are more ...

  6. Molecular Engineering, Photophysical and Electrochemical Characterizations of Novel Ru(II) and BODIPY Sensitizers for Mesoporous TiO2 Solar Cells

    Science.gov (United States)

    Cheema, Hammad Arshad

    To realize the dream of a low carbon society and ensure the wide spread application of renewable energy sources such as solar energy, photovoltaic devices should be highly efficient, cost-effective and stable for at least 20 years. Dye sensitized solar cells (DSCs) are photovoltaic cells that mimic the natural photosynthesis. In a DSC, the dye absorbs photons from incident light and converts those photons to electric charges, which are then extracted to the outer circuit through semiconductor TiO2, whereas the mediator regenerates the oxidized dye. A sensitizer is the pivotal component in the device in terms of determining the spectral response, color, photocurrent density, long term stability, and thickness of a DSC. The breakthrough report by O'Regan and Gratzel in 1991 has garnered more than 18,673 citations (as of October 9, 2014), which indicates the immense scientific interest to better understand and improve the fundamental science of this technology. With the aforementioned in mind, this study has focused on the molecular engineering of novel sensitizers to provide a better understanding of structure-property relationships of novel sensitizers for DSCs. The characterization of sensitizers (HD-1-mono, HD-2-mono and HD-2) for photovoltaic applications showed that the photocurrent response of DSCs can be increased by using mono-ancillary ligand instead of bis-ancillary ligands, which is of great commercial value considering the difference in the molecular weights of both dyes. The results of this work were published in Journal of Materials Chemistry A (doi:10.1039/c4ta01942c) and ACS Applied Materials and Interfaces (doi: 10.1021/am502400b). Furthermore, structure-property relationships were investigated in Ru (II) sensitizers HL-41 and HL-42 in order to elucidate the steric effects of electron donating ancillary ligands on photocurrent and photovoltage, as discussed in Chapter 4. It was found that the electron donating group (ethoxy) ortho to the CH=CH spacer

  7. Mod II engine performance

    Science.gov (United States)

    Richey, Albert E.; Huang, Shyan-Cherng

    1987-01-01

    The testing of a prototype of an automotive Stirling engine, the Mod II, is discussed. The Mod II is a one-piece cast block with a V-4 single-crankshaft configuration and an annular regenerator/cooler design. The initial testing of Mod II concentrated on the basic engine, with auxiliaries driven by power sources external to the engine. The performance of the engine was tested at 720 C set temperature and 820 C tube temperature. At 720 C, it is observed that the power deficiency is speed dependent and linear, with a weak pressure dependency, and at 820 C, the power deficiency is speed and pressure dependent. The effects of buoyancy and nozzle spray pattern on the heater temperature spread are investigated. The characterization of the oil pump and the operating cycle and temperature spread tests are proposed for further evaluation of the engine.

  8. Mechanical engineering

    CERN Document Server

    Darbyshire, Alan

    2010-01-01

    Alan Darbyshire's best-selling text book provides five-star high quality content to a potential audience of 13,000 engineering students. It explains the most popular specialist units of the Mechanical Engineering, Manufacturing Engineering and Operations & Maintenance Engineering pathways of the new 2010 BTEC National Engineering syllabus. This challenging textbook also features contributions from specialist lecturers, ensuring that no stone is left unturned.

  9. Stock Status

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data inform the public of the most recent stock status for a