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Sample records for hydrogen-oxygen electrolytic regenerative

  1. Hydrogen-Oxygen PEM Regenerative Fuel Cell Energy Storage System

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Scullin, Vincent J.; Chang, Bei-Jiann; Johnson, Donald W.; Garcia, Christopher P.

    2005-01-01

    An introduction to the closed cycle hydrogen-oxygen polymer electrolyte membrane (PEM) regenerative fuel cell (RFC), recently constructed at NASA Glenn Research Center, is presented. Illustrated with explanatory graphics and figures, this report outlines the engineering motivations for the RFC as a solar energy storage device, the system requirements, layout and hardware detail of the RFC unit at NASA Glenn, the construction history, and test experience accumulated to date with this unit.

  2. SPE (tm) regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications

    NASA Technical Reports Server (NTRS)

    Mcelroy, J. F.

    1990-01-01

    Viewgraphs on SPE regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications are presented. Topics covered include: hydrogen-oxygen regenerative fuel cell energy storage system; electrochemical cell reactions; SPE cell voltage stability; passive water removal SPE fuel cell; fuel cell performance; SPE water electrolyzers; hydrophobic oxygen phase separator; hydrophilic/electrochemical hydrogen phase separator; and unitized regenerative fuel cell.

  3. SPE (tm) regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications

    NASA Technical Reports Server (NTRS)

    Mcelroy, J. F.

    1990-01-01

    Viewgraphs on SPE regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications are presented. Topics covered include: hydrogen-oxygen regenerative fuel cell energy storage system; electrochemical cell reactions; SPE cell voltage stability; passive water removal SPE fuel cell; fuel cell performance; SPE water electrolyzers; hydrophobic oxygen phase separator; hydrophilic/electrochemical hydrogen phase separator; and unitized regenerative fuel cell.

  4. Thermally regenerative hydrogen/oxygen fuel cell power cycles

    NASA Astrophysics Data System (ADS)

    Morehouse, J. H.

    1986-07-01

    Two innovative thermodynamic power cycles are analytically examined for future engineering feasibility. The power cycles use a hydrogen-oxygen fuel cell for electrical energy production and use the thermal dissociation of water for regeneration of the hydrogen and oxygen. The TDS (thermal dissociation system) uses a thermal energy input at over 2000 K to thermally dissociate the water. The other cycle, the HTE (high temperature electrolyzer) system, dissociates the water using an electrolyzer operating at high temperature (1300 K) which receives its electrical energy from the fuel cell. The primary advantages of these cycles is that they are basically a no moving parts system, thus having the potential for long life and high reliability, and they have the potential for high thermal efficiency. Both cycles are shown to be classical heat engines with ideal efficiency close to Carnot cycle efficiency. The feasibility of constructing actual cycles is investigated by examining process irreversibilities and device efficiencies for the two types of cycles. The results show that while the processes and devices of the 2000 K TDS exceed current technology limits, the high temperature electrolyzer system appears to be a state-of-the-art technology development. The requirements for very high electrolyzer and fuel cell efficiencies are seen as determining the feasbility of the HTE system, and these high efficiency devices are currently being developed. It is concluded that a proof-of-concept HTE system experiment can and should be conducted.

  5. Thermally regenerative hydrogen/oxygen fuel cell power cycles

    NASA Technical Reports Server (NTRS)

    Morehouse, J. H.

    1986-01-01

    Two innovative thermodynamic power cycles are analytically examined for future engineering feasibility. The power cycles use a hydrogen-oxygen fuel cell for electrical energy production and use the thermal dissociation of water for regeneration of the hydrogen and oxygen. The TDS (thermal dissociation system) uses a thermal energy input at over 2000 K to thermally dissociate the water. The other cycle, the HTE (high temperature electrolyzer) system, dissociates the water using an electrolyzer operating at high temperature (1300 K) which receives its electrical energy from the fuel cell. The primary advantages of these cycles is that they are basically a no moving parts system, thus having the potential for long life and high reliability, and they have the potential for high thermal efficiency. Both cycles are shown to be classical heat engines with ideal efficiency close to Carnot cycle efficiency. The feasibility of constructing actual cycles is investigated by examining process irreversibilities and device efficiencies for the two types of cycles. The results show that while the processes and devices of the 2000 K TDS exceed current technology limits, the high temperature electrolyzer system appears to be a state-of-the-art technology development. The requirements for very high electrolyzer and fuel cell efficiencies are seen as determining the feasbility of the HTE system, and these high efficiency devices are currently being developed. It is concluded that a proof-of-concept HTE system experiment can and should be conducted.

  6. Hydrogen-Oxygen PEM Regenerative Fuel Cell at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    2004-01-01

    The NASA Glenn Research Center has constructed a closed-cycle hydrogen-oxygen PEM regenerative fuel cell (RFC) to explore its potential use as an energy storage device for a high altitude solar electric aircraft. Built up over the last 2 years from specialized hardware and off the shelf components the Glenn RFC is a complete "brassboard" energy storage system which includes all the equipment required to (1) absorb electrical power from an outside source and store it as pressurized hydrogen and oxygen and (2) make electrical power from the stored gases, saving the product water for re-use during the next cycle. It consists of a dedicated hydrogen-oxygen fuel cell stack and an electrolyzer stack, the interconnecting plumbing and valves, cooling pumps, water transfer pumps, gas recirculation pumps, phase separators, storage tanks for oxygen (O2) and hydrogen (H2), heat exchangers, isolation valves, pressure regulators, nitrogen purge provisions, instrumentation, and other components. It specific developmental functions include: (1) Test fuel cells and fuel cell components under repeated closed-cycle operation (nothing escapes; everything is used over and over again). (2) Simulate diurnal charge-discharge cycles (3) Observe long-term system performance and identify degradation and loss mechanisms. (4) Develop safe and convenient operation and control strategies leading to the successful development of mission-capable, flight-weight RFC's.

  7. Hydrogen-Oxygen PEM Regenerative Fuel Cell Development at the NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Scullin, Vincent J.; Chang, Bei-Jiann; Johnson, Donald W.; Garcia, Christoher P.; Jakupca, Ian J.

    2005-01-01

    The closed-cycle hydrogen-oxygen PEM regenerative fuel cell (RFC) at the NASA Glenn Research Center has successfully demonstrated closed cycle operation at rated power for multiple charge-discharge cycles. During charge cycle the RFC has absorbed input electrical power simulating a solar day cycle ranging from zero to 15 kWe peak, and delivered steady 5 kWe output power for periods exceeding 8 hr. Orderly transitions from charge to discharge mode, and return to charging after full discharge, have been accomplished without incident. Continuing test operations focus on: (1) Increasing the number of contiguous uninterrupted charge discharge cycles; (2) Increasing the performance envelope boundaries; (3) Operating the RFC as an energy storage device on a regular basis; (4) Gaining operational experience leading to development of fully automated operation; and (5) Developing instrumentation and in situ fluid sampling strategies to monitor health and anticipate breakdowns.

  8. Hydrogen-Oxygen PEM Regenerative Fuel Cell Development at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Scullin, Vincent J.; Chang, B. J.; Johnson, Donald W.; Garcia, Christopher P.; Jakupca, Ian J.

    2006-01-01

    The closed-cycle hydrogen-oxygen PEM regenerative fuel cell (RFC) at NASA Glenn Research Center has demonstrated multiple back to back contiguous cycles at rated power, and round trip efficiencies up to 52 percent. It is the first fully closed cycle regenerative fuel cell ever demonstrated (entire system is sealed: nothing enters or escapes the system other than electrical power and heat). During FY2006 the system has undergone numerous modifications and internal improvements aimed at reducing parasitic power, heat loss and noise signature, increasing its functionality as an unattended automated energy storage device, and in-service reliability. It also serves as testbed towards development of a 600 W-hr/kg flight configuration, through the successful demonstration of lightweight fuel cell and electrolyser stacks and supporting components. The RFC has demonstrated its potential as an energy storage device for aerospace solar power systems such as solar electric aircraft, lunar and planetary surface installations; any airless environment where minimum system weight is critical. Its development process continues on a path of risk reduction for the flight system NASA will eventually need for the manned lunar outpost.

  9. Properties of solid polymer electrolyte fluorocarbon film. [used in hydrogen/oxygen fuel cells

    NASA Technical Reports Server (NTRS)

    Alston, W. B.

    1973-01-01

    The ionic fluorocarbon film used as the solid polymer electrolyte in hydrogen/oxygen fuel cells was found to exhibit delamination failures. Polarized light microscopy of as-received film showed a lined region at the center of the film thickness. It is shown that these lines were not caused by incomplete saponification but probably resulted from the film extrusion process. The film lines could be removed by an annealing process. Chemical, physical, and tensile tests showed that annealing improved or sustained the water contents, spectral properties, thermo-oxidative stability, and tensile properties of the film. The resistivity of the film was significantly decreased by the annealing process.

  10. Electrolyte for batteries with regenerative solid electrolyte interface

    DOEpatents

    Xiao, Jie; Lu, Dongping; Shao, Yuyan; Bennett, Wendy D.; Graff, Gordon L.; Liu, Jun; Zhang, Ji-Guang

    2017-08-01

    An energy storage device comprising: an anode; and a solute-containing electrolyte composition wherein the solute concentration in the electrolyte composition is sufficiently high to form a regenerative solid electrolyte interface layer on a surface of the anode only during charging of the energy storage device, wherein the regenerative layer comprises at least one solute or solvated solute from the electrolyte composition.

  11. Closed-Cycle Hydrogen-Oxygen Regenerative Fuel Cell at the NASA Glenn Research Center-An Update

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Chang, Bei-Jiann; Johnson, Donald W.; Garcia, Christopher P.

    2008-01-01

    The closed cycle hydrogen-oxygen proton exchange membrane (PEM) regenerative fuel cell (RFC) at the NASA Glenn Research Center has demonstrated multiple back-to-back contiguous cycles at rated power and round-trip efficiencies up to 52 percent. It is the first fully closed cycle RFC ever demonstrated. (The entire system is sealed; nothing enters or escapes the system other than electrical power and heat.) During fiscal year fiscal year (FY) FY06 to FY07, the system s numerous modifications and internal improvements focused on reducing parasitic power, heat loss, and noise signature; increasing its functionality as an unattended automated energy storage device; and in-service reliability.

  12. Regenerative Hydrogen-oxygen Fuel Cell-electrolyzer Systems for Orbital Energy Storage

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.

    1984-01-01

    Fuel cells have found application in space since Gemini. Over the years technology advances have been factored into the mainstream hardware programs. Performance levels and service lives have been gradually improving. More recently, the storage application for fuel cell-electrolyzer combinations are receiving considerable emphasis. The regenerative system application described here is part of a NASA Fuel Cell Program which was developed to advance the fuel cell and electrolyzer technology required to satisfy the identified power generation and energy storage need of the Agency for space transportation and orbital applications to the year 2000.

  13. Design considerations for a 10-kW integrated hydrogen-oxygen regenerative fuel cell system

    NASA Technical Reports Server (NTRS)

    Hoberecht, M. A.; Miller, T. B.; Rieker, L. L.; Gonzalez-Sanabria, O. D.

    1984-01-01

    Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low earth orbit (LEO) applications characterized by relatively high overall round trip electrical efficiency, long life, and high reliability is possible with present state of the art technology. A hypothetical 10 kW system computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is under development utilizing advanced cell components and standard Shuttle Orbiter system hardware. The alkaline electrolysis technology uses a static water vapor feed technique and scaled up cell hardware is developed. The computer aided study of the performance, operating, and design parameters of the hypothetical system is addressed.

  14. Design considerations for a 10-kW integrated hydrogen-oxygen regenerative fuel cell system

    NASA Astrophysics Data System (ADS)

    Hoberecht, M. A.; Miller, T. B.; Rieker, L. L.; Gonzalez-Sanabria, O. D.

    Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low earth orbit (LEO) applications characterized by relatively high overall round trip electrical efficiency, long life, and high reliability is possible with present state of the art technology. A hypothetical 10 kW system computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is under development utilizing advanced cell components and standard Shuttle Orbiter system hardware. The alkaline electrolysis technology uses a static water vapor feed technique and scaled up cell hardware is developed. The computer aided study of the performance, operating, and design parameters of the hypothetical system is addressed.

  15. Design considerations for a 10-kW integrated hydrogen-oxygen regenerative fuel cell system

    NASA Technical Reports Server (NTRS)

    Hoberecht, M. A.; Miller, T. B.; Rieker, L. L.; Gonzalez-Sanabria, O. D.

    1984-01-01

    Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low earth orbit (LEO) applications characterized by relatively high overall round trip electrical efficiency, long life, and high reliability is possible with present state of the art technology. A hypothetical 10 kW system computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is under development utilizing advanced cell components and standard Shuttle Orbiter system hardware. The alkaline electrolysis technology uses a static water vapor feed technique and scaled up cell hardware is developed. The computer aided study of the performance, operating, and design parameters of the hypothetical system is addressed.

  16. Design considerations for a 10-KW integrated hydrogen-oxygen regenerative fuel cell system

    SciTech Connect

    Hoberecht, M.A.; Gonzalez-Sanabria, O.D.; Miller, T.B.; Rieker, L.L.

    1984-08-01

    Integration of an alkaline fuel cell subsystem with an alkaline electrolysis subsystem to form a regenerative fuel cell (RFC) system for low-earth-orbit (LEO) applications characterized by relatively high overall round-trip electrical efficiency, long life, and high reliability is possible with present state-of-the-art technology. A hypothetical 10-kW system is being computer modeled and studied based on data from ongoing contractual efforts in both the alkaline fuel cell and alkaline water electrolysis areas. The alkaline fuel cell technology is being developed under an NASA-LeRC program with United Technologies Corporation (UTC), utilizing advanced cell components and standard Shuttle-Orbiter system hardware. The alkaline electrolysis technology is that of Life Systems, Inc. (LSI), which uses a static water vapor feed technique and scaled-up cell hardware being developed under an NASA-LeRC program. This paper addresses the computeraided study of the performance, operating, and design parameters of the hypothetical system.

  17. Modeling the performance of hydrogen-oxygen unitized regenerative proton exchange membrane fuel cells for energy storage

    NASA Astrophysics Data System (ADS)

    Guarnieri, Massimo; Alotto, Piergiorgio; Moro, Federico

    2015-11-01

    Thanks to the independent sizing of power and energy, hydrogen-based energy storage is one of the very few technologies capable of providing long operational times in addition to the other advantages offered by electrochemical energy storage, for example scalability, site versatility, and mobile service. The typical design consists of an electrolyzer in charge mode and a separate fuel cell in discharge mode. Instead, a unitized regenerative fuel cell (URFC) is a single device performing both energy conversions, achieving a higher compactness and power-to-weight ratio. This paper presents a performance model of a URFC based on a proton exchange membrane (PEM) electrolyte and working on hydrogen and oxygen, which can provide high energy and power densities (>0.7 W cm-2). It provides voltage, power, and efficiency at varying load conditions as functions of the controlling physical quantities: temperature, pressure, concentration, and humidification. The model constitutes a tool for designing the interface and control sub-system as well as for exploring optimized cell/stack designs and operational conditions. To date, only a few of such analyses have been carried out and more research is needed in order to explore the true potential of URFCs.

  18. A 37.5-kW point design comparison of the nickel-cadmium battery, bipolar nickel-hydrogen battery, and regenerative hydrogen-oxygen fuel cell energy storage subsystems for low earth orbit

    NASA Technical Reports Server (NTRS)

    Manzo, M. A.; Hoberecht, M. A.

    1984-01-01

    Nickel-cadmium batteries, bipolar nickel-hydrogen batteries, and regenerative fuel cell storage subsystems were evaluated for use as the storage subsystem in a 37.5 kW power system for Space Station. Design requirements were set in order to establish a common baseline for comparison purposes. The storage subsystems were compared on the basis of effective energy density, round trip electrical efficiency, total subsystem weight and volume, and life.

  19. A 37.5-kW point design comparison of the nickel-cadmium battery, bipolar nickel-hydrogen battery, and regenerative hydrogen-oxygen fuel cell energy storage subsystems for low earth orbit

    NASA Technical Reports Server (NTRS)

    Manzo, M. A.; Hoberecht, M. A.

    1984-01-01

    Nickel-cadmium batteries, bipolar nickel-hydrogen batteries, and regenerative fuel cell storage subsystems were evaluated for use as the storage subsystem in a 37.5 kW power system for Space Station. Design requirements were set in order to establish a common baseline for comparison purposes. The storage subsystems were compared on the basis of effective energy density, round trip electrical efficiency, total subsystem weight and volume, and life.

  20. A 37.5-kW point design comparison of the nickel-cadmium battery, bipolar nickel-hydrogen battery, and regenerative hydrogen-oxygen fuel cell energy storage subsystems for low Earth orbit

    NASA Technical Reports Server (NTRS)

    Manzo, M. A.; Hoberecht, M. A.

    1984-01-01

    Nickel-cadmium batteries, bipolar nickel-hydrogen batteries, and regenerative fuel cell storage subsystems were evaluated for use as the storage subsystem in a 37.5 kW power system for space station. Design requirements were set in order to establish a common baseline for comparison purposes. The storage subsystems were compared on the basis of effective energy density, round trip electrical efficiency, total subsystem weight and volume, and life.

  1. Investigation of a chemically regenerative redox cathode polymer electrolyte fuel cell using a phosphomolybdovanadate polyoxoanion catholyte

    NASA Astrophysics Data System (ADS)

    Gunn, Natasha L. O.; Ward, David B.; Menelaou, Constantinos; Herbert, Matthew A.; Davies, Trevor J.

    2017-04-01

    Chemically regenerative redox cathode (CRRC) polymer electrolyte fuel cells (PEFCs), where the direct reduction of oxygen is replaced by an in-direct mechanism occurring outside of the cell, are attractive to study as they offer a solution to the cost and durability problems faced by conventional PEFCs. This study reports the first detailed characterization of a high performance complete CRRC PEFC system, where catholyte is circulated between the cathode side of the cell and an air-liquid oxidation reactor called the ;regenerator;. The catholyte is an aqueous solution of phosphomolybdovanadate polyoxoanion and is assessed in terms of its performance within both a small single cell and corresponding regenerator over a range of redox states. Two methods for determining regeneration rate are proposed and explored. Expressing the regeneration rate as a ;chemical; current is suggested as a useful means of measuring re-oxidation rate with respect to the cell. The analysis highlights the present limitations to the technology and provides an indication of the maximum power density achievable, which is highly competitive with conventional PEFC systems.

  2. Regenerative fuel cell systems R and D

    SciTech Connect

    Mitlitsky, F.; Myers, B.; Weisberg, A.H.

    1998-08-01

    Regenerative fuel cell (RFC) systems produce power and electrolytically regenerate their reactants using stacks of electrochemical cells. Energy storage systems with extremely high specific energy (> 400 Wh/kg) have been designed that use lightweight pressure vessels to contain the gases generated by reversible (unitized) regenerative fuel cells (URFCs). Progress is reported on the development, integration, and operation of rechargeable energy storage systems with such high specific energy. Lightweight pressure vessels that enable high specific energies have been designed with performance factors (burst pressure/internal volume/tank weight) > 50 km (2.0 million inches), and a vessel with performance factor of 40 km (1.6 million inches) was fabricated. New generations of both advanced and industry-supplied hydrogen tankage are under development. A primary fuel cell test rig with a single cell (46 cm{sup 2} active area) has been modified and operated reversibly as a URFC (for up to 2010 cycles on a single cell). This URFC uses bifunctional electrodes (oxidation and reduction electrodes reverse roles when switching from charge to discharge, as with a rechargeable battery) and cathode feed electrolysis (water is fed from the hydrogen side of the cell). Recent modifications also enable anode feed electrolysis (water is fed from the oxygen side of the cell). Hydrogen/halogen URFCs, capable of higher round-trip efficiency than hydrogen/oxygen URFCs, have been considered, and will be significantly heavier. Progress is reported on higher performance hydrogen/oxygen URFC operation with reduced catalyst loading.

  3. Unitized Regenerative Fuel Cells for solar rechargeable aircraft and zero emission vehicles

    NASA Astrophysics Data System (ADS)

    Mitlitsky, Fred; Colella, Nicholas J.; Myers, Blake

    1994-09-01

    A unitized regenerative fuel cell (URFC) produces power and electrolytically regenerates its reactants using a single stack of reversible cells. URFC'S have been designed for high altitude long endurance (HALE) solar rechargeable aircraft (SRA), zero emission vehicles (ZEV's), hybrid energy storage/propulsion systems for long duration satellites, energy storage for remote (off-grid) power sources, and peak shaving for on-grid applications. URFC's have been considered using hydrogen/oxygen, hydrogen/air, or hydrogen/halogen chemistries. This discussion is limited to the lightweight URFC energy storage system designs for span-loaded HALE SRA using hydrogen/oxygen, and for ZEV's using hydrogen/air with oxygen supercharging. Overlapping and synergistic development and testing opportunities for these two technologies will be highlighted.

  4. A premixed hydrogen/oxygen catalytic igniter

    NASA Technical Reports Server (NTRS)

    Green, James M.

    1989-01-01

    The catalytic ignition of hydrogen and oxygen propellants was studied using a premixing hydrogen/oxygen injector. The premixed injector was designed to eliminate problems associated with catalytic ignition caused by poor propellant mixing in the catalyst bed. Mixture ratio, mass flow rate, and propellant inlet temperature were varied parametrically in testing, and a pulse mode life test of the igniter was conducted. The results of the tests showed that the premixed injector eliminated flame flashback in the reactor and increased the life of the igniter significantly. The results of the experimental program and a comparison with data collected in a previous program are given.

  5. Hydrogen/oxygen auxiliary propulsion technology

    NASA Technical Reports Server (NTRS)

    Reed, Brian D.; Schneider, Steven J.

    1991-01-01

    A survey is provided of hydrogen/oxygen (H/O) auxiliary propulsion system (APS) concepts and low thrust H/O rocket technology. A review of H/O APS studies performed for the Space Shuttle, Space Tug, Space Station Freedom, and Advanced Manned Launch System programs is given. The survey also includes a review of low thrust H/O rocket technology programs, covering liquid H/O and gaseous H/O thrusters, ranging from 6600 N (1500 lbf) to 440 mN (0.1 lbf) thrust. Ignition concepts for H/O thrusters and high temperature, oxidation resistant chamber materials are also reviewed.

  6. Catalytic ignition of hydrogen/oxygen

    NASA Technical Reports Server (NTRS)

    Green, James M.; Zurawski, Robert L.

    1988-01-01

    An experimental program was conducted to evaluate the catalytic ignition of gaseous hydrogen and oxygen. Shell 405 granular catalyst and a unique monolithic sponge catalyst were tested. Mixture ratio, mass flow rate, propellant inlet temperature, and back pressure were varied parametrically in testing to determine the operational limits of a catalytic igniter. The test results showed that the gaseous hydrogen/oxygen propellant combination can be ignited catalytically using Shell 405 catalyst over a wide range of mixture ratios, mass flow rates, and propellant injection temperatures. These operating conditions must be optimized to ensure reliable ignition for an extended period of time. The results of the experimental program and the established operational limits for a catalytic igniter using both the granular and monolithic catalysts are presented. The capabilities of a facility constructed to conduct the igniter testing and the advantages of a catalytic igniter over other ignition systems for gaseous hydrogen and oxygen are also discussed.

  7. Gaseous hydrogen/oxygen injector performance characterization

    NASA Technical Reports Server (NTRS)

    Degroot, W. A.; Tsuei, H. H.

    1994-01-01

    Results are presented of spontaneous Raman scattering measurements in the combustion chamber of a 110 N thrust class gaseous hydrogen/oxygen rocket. Temperature, oxygen number density, and water number density profiles at the injector exit plane are presented. These measurements are used as input profiles to a full Navier-Stokes computational fluid dynamics (CFD) code. Predictions of this code while using the measured profiles are compared with predictions while using assumed uniform injector profiles. Axial and radial velocity profiles derived from both sets of predictions are compared with Rayleigh scattering measurements in the exit plane of a 33:1 area ratio nozzle. Temperature and number density Raman scattering measurements at the exit plane of a test rocket with a 1:1.36 area ratio nozzle are also compared with results from both sets of predictions.

  8. Auditory Risk of Exploding Hydrogen-Oxygen Balloons

    ERIC Educational Resources Information Center

    Gee, Kent L.; Vernon, Julia A.; Macedone, Jeffrey H.

    2010-01-01

    Although hydrogen-oxygen balloon explosions are popular demonstrations, the acoustic impulse created poses a hearing damage risk if the peak level exceeds 140 dB at the listener's ear. The results of acoustical measurements of hydrogen-oxygen balloons of varying volume and oxygen content are described. It is shown that hydrogen balloons may be…

  9. Auditory Risk of Exploding Hydrogen-Oxygen Balloons

    ERIC Educational Resources Information Center

    Gee, Kent L.; Vernon, Julia A.; Macedone, Jeffrey H.

    2010-01-01

    Although hydrogen-oxygen balloon explosions are popular demonstrations, the acoustic impulse created poses a hearing damage risk if the peak level exceeds 140 dB at the listener's ear. The results of acoustical measurements of hydrogen-oxygen balloons of varying volume and oxygen content are described. It is shown that hydrogen balloons may be…

  10. Round Trip Energy Efficiency of NASA Glenn Regenerative Fuel Cell System

    NASA Technical Reports Server (NTRS)

    Garcia, Christopher P.; Chang, Bei-jiann; Johnson, Donald W.; Bents, David J.; Scullin, Vincent J.; Jakupca, Ian J.; Scullin, Vincent J.; Jakupca, Ian J.

    2006-01-01

    NASA Glenn Research Center (GRC) has recently demonstrated a Polymer Electrolyte Membrane (PEM) based hydrogen/oxygen regenerative fuel cell system (RFCS) that operated for a charge/discharge cycle with round trip efficiency (RTE) greater than 50 percent. The regenerative fuel cell system (RFCS) demonstrated closed loop energy storage over a pressure range of 90 to 190 psig. In charge mode, a constant electrical power profile of 7.1 kWe was absorbed by the RFCS and stored as pressurized hydrogen and oxygen gas. In discharge mode, the system delivered 3 to 4 kWe of electrical power along with product water. Fuel cell and electrolyzer power profiles and polarization performance are documented in this paper. Individual cell performance and the variation of cell voltages within the electrochemical stacks are also reported. Fuel cell efficiency, electrolyzer efficiency, and the system RTE were calculated from the test data and are included below.

  11. Regenerative fuel cell study for satellites in GEO orbit

    NASA Technical Reports Server (NTRS)

    Vandine, Leslie; Gonzalez-Sanabria, Olga; Levy, Alexander

    1987-01-01

    The results of a 12 month study to identify high performance regenerative hydrogen-oxygen fuel cell concepts for geosynchronous satellite application are summarized. Emphasis was placed on concepts with the potential for high energy density and passive means for water and heat management to maximize system reliability. Both polymer membrane and alkaline electrolyte fuel cells were considered, with emphasis on the alkaline cell because of its high performance, advanced state of development, and proven ability to operate in a launch and space environment. Three alkaline system concepts were studied. Results indicate that using near term technology energy densities between 46 and 52 watt-hour/lb can be achieved at efficiencies of 55 percent. Using advanced light weight cell construction which was achieved in experimental cells, composite tankage material for the reactant gases and the reversible stack concept, system energy densities of 115 watt-hours/lb can be projected.

  12. Hydrogen-oxygen proton-exchange membrane fuel cells and electrolyzers

    NASA Technical Reports Server (NTRS)

    Baldwin, R.; Pham, M.; Leonida, A.; Mcelroy, J.; Nalette, T.

    1989-01-01

    Hydrogen-oxygen solid polymer electrolyte (SPE) fuel cells and SPE electrolyzers (products of Hamilton Standard) both use a Proton-Exchange Membrane (PEM) as the sole electrolyte. These solid electrolyte devices have been under continuous development for over 30 years. This experience has resulted in a demonstrated ten-year SPE cell life capability under load conditions. Ultimate life of PEM fuel cells and electrolyzers is primarily related to the chemical stability of the membrane. For perfluorocarbon proton exchange membranes an accurate measure of the membrane stability is the fluoride loss rate. Millions of cell hours have contributed to establishing a relationship between fluoride loss rates and average expected ultimate cell life. This relationship is shown. Several features have been introduced into SPE fuel cells and SPE electrolyzers such that applications requiring greater than or equal to 100,000 hours of life can be considered. Equally important as the ultimate life is the voltage stability of hydrogen-oxygen fuel cells and electrolyzers. Here again the features of SPE fuel cells and SPE electrolyzers have shown a cell voltage stability in the order of 1 microvolt per hour. That level of stability has been demonstrated for tens of thousands of hours in SPE fuel cells at up to 500 amps per square foot (ASF) current density.

  13. Electrolytes

    MedlinePlus

    ... Chloride Magnesium Phosphorus Potassium Sodium Electrolytes can be acids, bases, or salts. They can be measured by different ... Saunders; 2013:464-467. DuBose TD. Disorders of acid-base balance. In: Taal MW, Chertow GM, Marsden PA, ...

  14. Test of Hydrogen-Oxygen PEM Fuel Cell Stack at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Bents, David J.; Scullin, Vincent J.; Chang, Bei-Jiann; Johnson, Donald W.; Garcia, Christopher P.; Jakupca, Ian J.

    2003-01-01

    This paper describes performance characterization tests of a 64 cell hydrogen oxygen PEM fuel cell stack at NASA Glenn Research Center in February 2003. The tests were part of NASA's ongoing effort to develop a regenerative fuel cell for aerospace energy storage applications. The purpose of the tests was to verify capability of this stack to operate within a regenerative fuel cell, and to compare performance with earlier test results recorded by the stack developer. Test results obtained include polarization performance of the stack at 50 and 100 psig system pressure, and a steady state endurance run at 100 psig. A maximum power output of 4.8 kWe was observed during polarization runs, and the stack sustained a steady power output of 4.0 kWe during the endurance run. The performance data obtained from these tests compare reasonably close to the stack developer's results although some additional spread between best to worst performing cell voltages was observed. Throughout the tests, the stack demonstrated the consistent performance and repeatable behavior required for regenerative fuel cell operation.

  15. Acoustical characterization of exploding hydrogen-oxygen balloons.

    PubMed

    Vernon, Julia A; Gee, Kent L; Macedone, Jeffrey H

    2012-03-01

    Exploding hydrogen-oxygen balloons are popular chemistry demonstrations. Although initial research experimentally quantified potential hearing risk via analysis of peak levels [K. L. Gee et al., J. Chem. Educ. 87, 1039-1044 (2010)], further waveform and spectral analyses have been conducted to more fully characterize these impulsive noise sources. While hydrogen-only balloons produce inconsistent reactions and relatively low, variable levels, stoichiometrically mixed hydrogen-oxygen balloons produce consistent high-amplitude noise waveforms. Preliminary consideration is also given to the potential use of these exploding balloons in architectural acoustics applications.

  16. HYDROGEN-OXYGEN PRIMARY EXTRATERRESTRIAL (HOPE) FUEL CELL PROGRAM

    DTIC Science & Technology

    The HOPE (Hydrogen-Oxygen Primary Extraterrestrial) Fuel Cell Program is a multi-phase effort to advance the state-of-the-art of fuel cells by...configuration fuel cell module. The HOPE spacecraft, fuel supply tanks, pneumatics, and thermal systems were designed and fabricated to provide...verify water removal, thermal design, and 30-day shelf-life of the fuel cell . The 35-cell module was subjected to a series of performance tests

  17. Characteristics of Knock in Hydrogen-Oxygen-Argon SI Engine

    SciTech Connect

    Killingsworth, N; Rapp, V; Flowers, D; Aceves, S; Chen, J; Dibble, R

    2010-02-23

    A promising approach for improving the efficiency of internal combustion engines is to employ a working fluid with a high specific heat ratio such as the noble gas argon. Moreover, all harmful emissions are eliminated when the intake charge is composed of oxygen, nonreactive argon, and hydrogen fuel. Previous research demonstrated indicated thermal efficiencies greater than 45% at 5.5 compression ratio in engines operating with hydrogen, oxygen, and argon. However, knock limits spark advance and increasing the efficiency further. Conditions under which knock occurs in such engines differs from typical gasoline fueled engines. In-cylinder temperatures using hydrogen-oxygen-argon are higher due to the high specific heat ratio and pressures are lower because of the low compression ratio. Better understanding of knock under these conditions can lead to operating strategies that inhibit knock and allow operation closer to the knock limit. In this work we compare knock with a hydrogen, oxygen, and argon mixture to that of air-gasoline mixtures in a variable compression ratio cooperative fuels research (CFR) engine. The focus is on stability of knocking phenomena, as well as, amplitude and frequency of the resulting pressure waves.

  18. Lunar Regenerative Fuel Cell (RFC) Reliability Testing for Assured Mission Success

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    2009-01-01

    NASA's Constellation program has selected the closed cycle hydrogen oxygen Polymer Electrolyte Membrane (PEM) Regenerative Fuel Cell (RFC) as its baseline solar energy storage system for the lunar outpost and manned rover vehicles. Since the outpost and manned rovers are "human-rated," these energy storage systems will have to be of proven reliability exceeding 99 percent over the length of the mission. Because of the low (TRL=5) development state of the closed cycle hydrogen oxygen PEM RFC at present, and because there is no equivalent technology base in the commercial sector from which to draw or infer reliability information from, NASA will have to spend significant resources developing this technology from TRL 5 to TRL 9, and will have to embark upon an ambitious reliability development program to make this technology ready for a manned mission. Because NASA would be the first user of this new technology, NASA will likely have to bear all the costs associated with its development.When well-known reliability estimation techniques are applied to the hydrogen oxygen RFC to determine the amount of testing that will be required to assure RFC unit reliability over life of the mission, the analysis indicates the reliability testing phase by itself will take at least 2 yr, and could take up to 6 yr depending on the number of QA units that are built and tested and the individual unit reliability that is desired. The cost and schedule impacts of reliability development need to be considered in NASA's Exploration Technology Development Program (ETDP) plans, since life cycle testing to build meaningful reliability data is the only way to assure "return to the moon, this time to stay, then on to Mars" mission success.

  19. Regenerative fuel cells

    NASA Technical Reports Server (NTRS)

    Swette, Larry L.; Kackley, Nancy D.; Laconti, Anthony B.

    1992-01-01

    A development status evaluation is presented for moderate-temperature, single-unit, regenerative fuel cells using either alkaline or solid polymer proton-exchange membrane (PEM) electrolytes. Attention is given to the results thus far obtained for Pt, Ir, Rh, and Na(x)Pt3O4 catalysts. Alkaline electrolyte tests have been performed on a half-cell basis with a floating-electrode cell; PEM testing has been with complete fuel cells, using Nafion 117.

  20. Regenerative fuel cells

    NASA Astrophysics Data System (ADS)

    Swette, Larry L.; Kackley, Nancy D.; Laconti, Anthony B.

    A development status evaluation is presented for moderate-temperature, single-unit, regenerative fuel cells using either alkaline or solid polymer proton-exchange membrane (PEM) electrolytes. Attention is given to the results thus far obtained for Pt, Ir, Rh, and Na(x)Pt3O4 catalysts. Alkaline electrolyte tests have been performed on a half-cell basis with a floating-electrode cell; PEM testing has been with complete fuel cells, using Nafion 117.

  1. Hydrogen-oxygen proton-exchange membrane fuel cells and electrolyzers

    NASA Technical Reports Server (NTRS)

    Baldwin, R.; Pham, M.; Leonida, A.; Mcelroy, J.; Nalette, T.

    1989-01-01

    Hydrogen-oxygen SPE fuel cells and SPE electrolyzers (products of Hamilton Standard) both use a Proton-Exchange Membrane (PEM) as the sole electrolyte. The SPE cells have demonstrated a ten year life capability under load conditions. Ultimate life of PEM fuel cells and electrolyzers is primarily related to the chemical stability of the membrane. For perfluorocarbon proton-exchange membranes an accurate measure of the membrane stability is the fluoride loss rate. Millions of cell hours have contributed to establishing a relationship between fluroride loss rates and average expected ultimate cell life. Several features were introduced into SPE fuel cells and SPE electrolyzers such that applications requiring greater than or equal to 100,000 hours of life can be considered. Equally important as the ultimate life is the voltage stability of hydrogen-oxygen fuel cells and electrolyzers. Here again the features of SPE fuel cells and SPE electrolyzers have shown a cell voltage stability in the order of 1 microvolt per hour. That level of stability were demonstrated for tens of thousands of hours in SPE fuel cells at up to 500 amps per square foot (ASF) current density. The SPE electrolyzers have demonstrated the same at 1000 ASF. Many future extraterrestrial applications for fuel cells require that they be self recharged. To translate the proven SPE cell life and stability into a highly reliable extraterrestrial electrical energy storage system, a simplification of supporting equipment is required. Static phase separation, static fluid transport and static thermal control will be most useful in producting required system reliability. Although some 200,000 SPE fuel cell hours were recorded in earth orbit with static fluid phase separation, no SPE electrolyzer has, as yet, operated in space.

  2. Regenerative fuel cell study for satellites in GEO orbit

    NASA Technical Reports Server (NTRS)

    Levy, Alexander; Vandine, Leslie L.; Stedman, James K.

    1987-01-01

    Summarized are the results of a 12-month study to identify high performance regenerative hydrogen-oxygen fuel cell concepts for geosynchronous satellite application. Emphasis was placed on concepts with the potential for high energy density (W-hr/lb) and passive means for water and heat management to maximize system reliability. Both polymer membrane and alkaline electrolyte fuel cells were considered, with emphasis on the alkaline cell because of its high performance, advanced state of development, and proven ability to operate in a launch and space environment. Three alkaline system concepts were studied. The first, the integrated design, utilized a configuration in which the fuel cell and electrolysis cells are alternately stacked inside a pressure vessel. Product water is transferred by diffusion during electrolysis and waste heat is conducted through the pressure wall, thus using completely passive means for transfer and control. The second alkaline system, the dedicated design, uses a separate fuel cell and electrolysis stack so that each unit can be optimized in size and weight based on its orbital operating period. The third design was a dual function stack configuration, in which each cell can operate in both fuel cell and electrolysis mode, thus eliminating the need for two separate stacks and associated equipment. Results indicate that using near term technology energy densities between 46 and 52 W-hr/lb can be achieved at efficiencies of 55 percent. System densities of 115 W-hr/lb are contemplated.

  3. Regenerative fuel cell study for satellites in GEO orbit

    NASA Astrophysics Data System (ADS)

    Levy, Alexander; Vandine, Leslie L.; Stedman, James K.

    1987-07-01

    Summarized are the results of a 12-month study to identify high performance regenerative hydrogen-oxygen fuel cell concepts for geosynchronous satellite application. Emphasis was placed on concepts with the potential for high energy density (W-hr/lb) and passive means for water and heat management to maximize system reliability. Both polymer membrane and alkaline electrolyte fuel cells were considered, with emphasis on the alkaline cell because of its high performance, advanced state of development, and proven ability to operate in a launch and space environment. Three alkaline system concepts were studied. The first, the integrated design, utilized a configuration in which the fuel cell and electrolysis cells are alternately stacked inside a pressure vessel. Product water is transferred by diffusion during electrolysis and waste heat is conducted through the pressure wall, thus using completely passive means for transfer and control. The second alkaline system, the dedicated design, uses a separate fuel cell and electrolysis stack so that each unit can be optimized in size and weight based on its orbital operating period. The third design was a dual function stack configuration, in which each cell can operate in both fuel cell and electrolysis mode, thus eliminating the need for two separate stacks and associated equipment. Results indicate that using near term technology energy densities between 46 and 52 W-hr/lb can be achieved at efficiencies of 55 percent. System densities of 115 W-hr/lb are contemplated.

  4. Integrated hydrogen/oxygen technology applied to auxiliary propulsion systems

    NASA Technical Reports Server (NTRS)

    Gerhardt, David L.

    1990-01-01

    The purpose of the Integrated Hydrogen/Oxygen Technology (IHOT) study was to determine if the vehicle/mission needs and technology of the 1990's support development of an all cryogenic H2/O2 system. In order to accomplish this, IHOT adopted the approach of designing Integrated Auxiliary Propulsion Systems (IAPS) for a representative manned vehicle; the advanced manned launch system. The primary objectives were to develop IAPS concepts which appeared to offer viable alternatives to state-of-the-art (i.e., hypergolic, or earth-storable) APS approaches. The IHOT study resulted in the definition of three APS concepts; two cryogenic IAPS, and a third concept utilizing hypergolic propellants.

  5. Traction drive for cryogenic boost pump. [hydrogen oxygen rocket engines

    NASA Technical Reports Server (NTRS)

    Meyer, S.; Connelly, R. E.

    1981-01-01

    Two versions of a Nasvytis multiroller traction drive were tested in liquid oxygen for possible application as cryogenic boost pump speed reduction drives for advanced hydrogen-oxygen rocket engines. The roller drive, with a 10.8:1 reduction ratio, was successfully run at up to 70,000 rpm input speed and up to 14.9 kW (20 hp) input power level. Three drive assemblies were tested for a total of about three hours of which approximately one hour was at nominal full speed and full power conditions. Peak efficiency of 60 percent was determined. There was no evidence of slippage between rollers for any of the conditions tested. The ball drive, a version using balls instead of one row of rollers, and having a 3.25:1 reduction ratio, failed to perform satisfactorily.

  6. Advanced hydrogen/oxygen thrust chamber design analysis

    NASA Technical Reports Server (NTRS)

    Shoji, J. M.

    1973-01-01

    The results are reported of the advanced hydrogen/oxygen thrust chamber design analysis program. The primary objectives of this program were to: (1) provide an in-depth analytical investigation to develop thrust chamber cooling and fatigue life limitations of an advanced, high pressure, high performance H2/O2 engine design of 20,000-pounds (88960.0 N) thrust; and (2) integrate the existing heat transfer analysis, thermal fatigue and stress aspects for advanced chambers into a comprehensive computer program. Thrust chamber designs and analyses were performed to evaluate various combustor materials, coolant passage configurations (tubes and channels), and cooling circuits to define the nominal 1900 psia (1.31 x 10 to the 7th power N/sq m) chamber pressure, 300-cycle life thrust chamber. The cycle life capability of the selected configuration was then determined for three duty cycles. Also the influence of cycle life and chamber pressure on thrust chamber design was investigated by varying in cycle life requirements at the nominal chamber pressure and by varying the chamber pressure at the nominal cycle life requirement.

  7. Ignition of Hydrogen-Oxygen Mixtures Behind the Incident Shock Wave Front

    NASA Astrophysics Data System (ADS)

    Pavlov, V. A.; Gerasimov, G. Ya.

    2016-05-01

    Experimental investigation of the ignition of a stoichiometric hydrogen-oxygen mixture behind an incident shock wave in a shock tube at pressures p = 0.002-0.46 MPa and temperatures T = 500-1000 K is carried out. The existence of three limits of ignition typical of the ignition of hydrogen-oxygen mixtures in a spherical vessel is noted. It is shown that at pressures p ≥ 0.1 MPa the ignition of a hydrogen-oxygen mixture begins at a much lower temperature than the ignition of a hydrogen-air mixture. The measured induction times agree well with theoretical estimates.

  8. STUDY OF HYDROGEN-OXYGEN FUEL CELL ELECTRODES.

    DTIC Science & Technology

    fuel cell systems, including catalysts, electrodes and electrolytes, have been investigated. Of the metals studied, it was found that a platinum-palladium, electrically co-deposited catalyst gave the best performance at both the hydrogen and oxygen electrodes. Supporting data from single electrode studies and galvanostatic measurements are given. Experimental methods of depositing the catalyst were also studied. Ultrasonic impregnation of the electrode with the electroplating solution before electrodeposition produced, by far, the best electrochemical performance. Both

  9. Low temperature thermally regenerative electrochemical system

    DOEpatents

    Loutfy, Raouf O.; Brown, Alan P.; Yao, Neng-Ping

    1983-01-01

    A thermally regenerative electrochemical system including an electrochemical cell with two water-based electrolytes separated by an ion exchange membrane, at least one of the electrolytes containing a complexing agent and a salt of a multivalent metal whose respective order of potentials for a pair of its redox couples is reversible by a change in the amount of the complexing agent in the electrolyte, the complexing agent being removable by distillation to cause the reversal.

  10. Low-temperature thermally regenerative electrochemical system

    DOEpatents

    Loutfy, R.O.; Brown, A.P.; Yao, N.P.

    1982-04-21

    A thermally regenerative electrochemical system is described including an electrochemical cell with two water-based electrolytes separated by an ion exchange membrane, at least one of the electrolytes containing a complexing agent and a salt of a multivalent metal whose respective order of potentials for a pair of its redox couples is reversible by a change in the amount of the ocmplexing agent in the electrolyte, the complexing agent being removable by distillation to cause the reversal.

  11. Regenerative fuel cell study for satellites in GEO orbit. Final contractor report

    SciTech Connect

    Levy, A.; Vandine, L.L.; Stedman, J.K.

    1987-07-01

    Summarized are the results of a 12-month study to identify high performance regenerative hydrogen-oxygen fuel cell concepts for geosynchronous satellite application. Emphasis was placed on concepts with the potential for high energy density (W-hr/lb) and passive means for water and heat management to maximize system reliability. Both polymer membrane and alkaline electrolyte fuel cells were considered, with emphasis on the alkaline cell because of its high performance, advanced state of development, and proven ability to operate in a launch and space environment. Three alkaline system concepts were studied. The first, the integrated design, utilized a configuration in which the fuel cell and electrolysis cells are alternately stacked inside a pressure vessel. Product water is transferred by diffusion during electrolysis and waste heat is conducted through the pressure wall, thus using completely passive means for transfer and control. The second alkaline system, the dedicated design, uses a separate fuel cell and electrolysis stack so that each unit can be optimized in size and weight based on its orbital operating period. The third design was a dual function stack configuration, in which each cell can operate in both fuel cell and electrolysis mode, thus eliminating the need for two separate stacks and associated equipment. Results indicate that using near term technology energy densities between 46 and 52 W-hr/lb can be achieved at efficiencies of 55 percent. System densities of 115 W-hr/lb are contemplated.

  12. Regenerative Endodontics.

    PubMed

    Feigin, Kristina; Shope, Bonnie

    2017-09-01

    Regenerative endodontics has been defined as "biologically based procedure designed to replace damaged structures, including dentin and root structures, as well as cells of the pulp-dentin complex." This is an exciting and rapidly evolving field of human endodontics for the treatment of immature permanent teeth with infected root canal systems. These procedures have shown to be able not only to resolve pain and apical periodontitis but continued root development, thus increasing the thickness and strength of the previously thin and fracture-prone roots. In the last decade, over 80 case reports, numerous animal studies, and series of regenerative endodontic cases have been published. However, even with multiple successful case reports, there are still some remaining questions regarding terminology, patient selection, and procedural details. Regenerative endodontics provides the hope of converting a nonvital tooth into vital one once again.

  13. Regenerative endodontics.

    PubMed

    Simon, S; Smith, A J

    2014-03-01

    Significant advances in our understanding of the biological processes involved in tooth development and repair at the cellular and molecular levels have underpinned the newly emerging area of regenerative endodontics. Development of treatment protocols based on exploiting the natural wound healing properties of the dental pulp and applying tissue engineering principles has allowed reporting of case series showing preservation of tissue vitality and apexogenesis. To review current case series reporting regenerative endodontics. Current treatment approaches tend to stimulate more reparative than regenerative responses in respect of the new tissue generated, which often does not closely resemble the physiological structure of dentine-pulp. However, despite these biological limitations, such techniques appear to offer significant promise for improved treatment outcomes. Improved biological outcomes will likely emerge from the many experimental studies being reported and will further contribute to improvements in clinical treatment protocols.

  14. Highly efficient redox-driven reversible color switching of dye molecules via hydrogenation/oxygenation.

    PubMed

    Jiang, Yi-Fan; Yuan, Cheng-Zong; Zhou, Xiao; Guo, Hong-Li; Liu, Ya-Nan; Jiang, Nan; Xu, An-Wu

    2016-12-22

    We report a novel reversible color switching system based on one-pot hydrogenation/oxygenation reactions over Pd/CeO2-x catalysts and fast interconversion of thionine (TH(+)) and leuco thionine (LTH). Oxygen vacancies produced by Pd-catalyzed instant hydrogenation of CeO2 and strong metal-support interaction (SMSI) could lead to fast color switching.

  15. Solar Airplanes and Regenerative Fuel Cells

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    2007-01-01

    A solar electric aircraft with the potential to "fly forever" has captured NASA's interest, and the concept for such an aircraft was pursued under Aeronautics Environmental Research Aircraft and Sensor Technology (ERAST) project. Feasibility of this aircraft happens to depend on the successful development of solar power technologies critical to NASA's Exploration Initiatives; hence, there was widespread interest throughout NASA to bring these technologies to a flight demonstration. The most critical is an energy storage system to sustain mission power during night periods. For the solar airplane, whose flight capability is already limited by the diffuse nature of solar flux and subject to latitude and time of year constraints, the feasibility of long endurance flight depends on a storage density figure of merit better than 400-600 watt-hr per kilogram. This figure of merit is beyond the capability of present day storage technologies (other than nuclear) but may be achievable in the hydrogen-oxygen regenerative fuel cell (RFC). This potential has led NASA to undertake the practical development of a hydrogen-oxygen regenerative fuel cell, initially as solar energy storage for a high altitude UAV science platform but eventually to serve as the primary power source for NASAs lunar base and other planet surface installations. Potentially the highest storage capacity and lowest weight of any non-nuclear device, a flight-weight RFC aboard a solar-electric aircraft that is flown continuously through several successive day-night cycles will provide the most convincing demonstration that this technology's widespread potential has been realized. In 1998 NASA began development of a closed cycle hydrogen oxygen PEM RFC under the Aeronautics Environmental Research Aircraft and Sensor Technology (ERAST) project and continued its development, originally for a solar electric airplane flight, through FY2005 under the Low Emissions Alternative Power (LEAP) project. Construction of

  16. Proven, long-life hydrogen/oxygen thrust chambers for space station propulsion

    NASA Technical Reports Server (NTRS)

    Richter, G. Paul; Price, Harold G.

    1986-01-01

    A 25 lb sub f hydrogen/oxygen thruster has been developed and proven as a viable candidate to meet the needs of the Space Station Program. Likewise, a 50 lb sub f hydrogen/oxygen thrust chamber has been developed and has demonstrated reliable, long-life expectancy at anticipated Space Station operating conditions. Both these thrust chambers were based on design criteria developed in previous thruster programs. Extensive thermal analysis and models were used to design the thrusters to achieve total impulse goals of 2 million lb sub f sec. Test data from each thruster are compared to the analytical predictions for the performance and heat transfer characteristics. Also, the results of thrust chamber life verification tests are presented.

  17. Velocity, temperature, and electrical conductivity profiles in hydrogen-oxygen MHD duct flows

    NASA Technical Reports Server (NTRS)

    Greywall, M. S.; Pian, C. C. P.

    1978-01-01

    Two-dimensional duct flow computations for radial distributions of velocity, temperature, and electrical conductivity are reported. Calculations were carried out for the flow conditions representative of a hydrogen-oxygen combustion driven MHD duct. Results are presented for: profiles of developing flow in a smooth duct, and for profiles of fully developed pipe flow with a specified streamwise shear stress distribution. The predicted temperature and electrical conductivity profiles for the developing flows compare well with available experimental data.

  18. Regenerative Aerobraking

    NASA Technical Reports Server (NTRS)

    Moses, Robert W.

    2004-01-01

    NASA's exploration goals for Mars and Beyond will require new power systems and in situ resource utilization technologies. Regenerative aerobraking may offer a revolutionary approach for in situ power generation and oxygen harvesting during these exploration missions. In theory, power and oxygen can be collected during aerobraking and stored for later use in orbit or on the planet. This technology would capture energy and oxygen from the plasma field that occurs naturally during hypersonic entry using well understood principles of magnetohydrodynamics and oxygen filtration. This innovative approach generates resources upon arrival at the operational site, and thus greatly differs from the traditional approach of taking everything you need with you from Earth. Fundamental analysis, computational fluid dynamics, and some testing of experimental hardware have established the basic feasibility of generating power during a Mars entry. Oxygen filtration at conditions consistent with spacecraft entry parameters at Mars has been studied to a lesser extent. Other uses of the MHD power are presented. This paper illustrates how some features of regenerative aerobraking may be applied to support human and robotic missions at Mars.

  19. Regenerative Aerobraking

    NASA Astrophysics Data System (ADS)

    Moses, Robert W.

    2005-02-01

    NASA's exploration goals for Mars and Beyond will require new power systems and in situ resource utilization technologies. Regenerative aerobraking may offer a revolutionary approach for in situ power generation and oxygen harvesting during these exploration missions. In theory, power and oxygen can be collected during aerobraking and stored for later use in orbit or on the planet. This technology would capture energy and oxygen from the plasma field that occurs naturally during hypersonic entry using well understood principles of magnetohydrodynamics and oxygen filtration. This innovative approach generates resources upon arrival at the operational site, and thus greatly differs from the traditional approach of taking everything you need with you from Earth. Fundamental analysis, computational fluid dynamics, and some testing of experimental hardware have established the basic feasibility of generating power during a Mars entry. Oxygen filtration at conditions consistent with spacecraft entry parameters at Mars has been studied to a lesser extent. Other uses of the MHD power are presented. This paper illustrates how some features of regenerative aerobraking may be applied to support human and robotic missions at Mars.

  20. NASA Lewis Evaluation of Regenerative Fuel Cell (RFC) Systems

    NASA Technical Reports Server (NTRS)

    Hagedorn, N. H.; Gonzalez-Sanabria, O. D; Kohout, L. L.

    1986-01-01

    Evaluation of two regenerative fuel cell (RFC) systems was begun in-house, and under contracts and grants. The passive hydrogen-oxygen RFC offers the possibility of a high-energy density, long-life storage system for geosynchronous Earth orbit missions. The hydrogen-bromine RFC offers the combination of high efficiency and moderate energy density that could ideally suit low Earth orbit missions if successfully developed. Either or both of these systems would be attractive additions to the storage options available to designers of future missions.

  1. High temperature solid oxide regenerative fuel cell for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1987-01-01

    A hydrogen-oxygen regenerative fuel cell (RFC) energy storage system based on high temperature solid oxide fuel cell (SOFC) technology is described. The reactants are stored as gases in lightweight insulated pressure vessels. The product water is stored as a liquid in saturated equilibrium with the fuel gas. The system functions as a secondary battery and is applicable to darkside energy storage for solar photovoltaics.

  2. Regenerative fuel cell energy storage system for a low Earth orbit space station

    SciTech Connect

    Martin, R.E.; Garow, J.; Michaels, K.B.

    1984-08-01

    Results of a study to define the characteristics of a regenerative fuel cell energy storage system for a large space station operating in low earth orbit (LEO) are presented. The regenerative fuel cell system employs an alkaline electrolyte fuel cell with the option of employing either an alkaline or a solid polymer electrolyte electrolyzer.

  3. Design of a Novel Gaseous Hydrogen-Oxygen Rocket Injector Element

    NASA Technical Reports Server (NTRS)

    Glenn, Dennis

    1999-01-01

    An overview of activities supporting the design of a gaseous hydrogen-oxygen rocket injector element is presented in viewgraph form. The purpose of the research was to find a viable design for a rocket gas-gas injector that mixes fuel and oxidizer thoroughly and quickly. Computational fluid dynamics analyses were used with reacting flow to evaluate design options for mixing, temperature distribution, and combustion efficiency. A design was found that is an improvement over designs derived from liquid systems and is far better than traditional shear-coax.

  4. Spectrally resolved Rayleigh scattering diagnostic for hydrogen-oxygen rocket plume studies

    NASA Technical Reports Server (NTRS)

    Seasholtz, R. G.; Zupanc, F. J.; Schneider, S. J.

    1991-01-01

    A Rayleigh scattering diagnostic has been developed to measure gas density, temperature, and velocity in the exhaust plume of 100 N thrust class hydrogen-oxygen rockets. The spectrum of argon-ion laser light scattered by the gas molecules in the plume (predominantly water vapor) is measured with a scanning Fabry-Perot interferometer. The gas density is determined from the total scattered power, the gas temperature from the spectral width, and the velocity from the shift in the peak of the spectrum from the frequency of the incident laser light. The diagnostic has been demonstrated in a rocket test cell and a discussion of results is given.

  5. Velocity, temperature, and electrical conductivity profiles in hydrogen-oxygen MHD duct flows

    NASA Technical Reports Server (NTRS)

    Greywall, M. S.; Pian, C. C. P.

    1978-01-01

    This paper presents results of two-dimensional duct flow computations for radial distributions of velocity, temperature, and electrical conductivity. Calculations were carried out for the flow conditions representative of NASA Lewis hydrogen-oxygen combustion driven MHD duct. Results are presented for two sets of computations: (1) profiles of developing flow in a smooth duct, and (2) profiles of fully developed pipe flow with a specified streamwise shear stress distribution. The predicted temperature and electrical conductivity profiles for the developing flows compared well with available experimental data.

  6. Theoretical investigation of the injection and evaporation of water in a hydrogen/oxygen steam generator

    NASA Astrophysics Data System (ADS)

    Beer, Stefan

    1990-05-01

    For the cooling of the reaction products resulting from a stoichiometric hydrogen/oxygen combustion, water is injected normal to the gas stream. The penetration of the jet strongly influences the temperature distribution across the streaming water vapor. The penetration of the jet is calculated by using the jet shedding model. The results are compared with the data of the garden hose model. To calculate the lifetime of a water droplet in super heated stream, several models are developed. The parameters of the injection and evaporation process are varied and analyzed.

  7. Investigation of spontaneous combustion of hydrogen-oxygen mixture using DSMC simulation

    NASA Astrophysics Data System (ADS)

    Yang, Chao; Sun, Quanhua

    2014-12-01

    Combustion has been widely studied in the literature, but very little work was focused on the microscopic level. In this paper, the DSMC method is applied to simulate the microscopic behavior of the spontaneous combustion of hydrogen oxygen mixture. It is found that the ignition delay time of the mixture depends on many factors, such as the physical size, temperature, pressure, and dilution. Comparison between DSMC and CFD results shows that more atomic hydrogen is consumed through reaction HO2+ H → H2+ O2 at temperature close to the extended second explosion limit due to localized distribution of reactants, which may indicate the importance of microscopic behavior on low temperature combustion.

  8. On the mechanism of the deflagration-to-detonation transition in a hydrogen-oxygen mixture

    SciTech Connect

    Liberman, M. A.; Ivanov, M. F.; Kiverin, A. D.; Kuznetsov, M. S.; Rakhimova, T. V.; Chukalovskii, A. A.

    2010-10-15

    The flame acceleration and the physical mechanism underlying the deflagration-to-detonation transition (DDT) have been studied experimentally, theoretically, and using a two-dimensional gasdynamic model for a hydrogen-oxygen gas mixture by taking into account the chain chemical reaction kinetics for eight components. A flame accelerating in a tube is shown to generate shock waves that are formed directly at the flame front just before DDT occurred, producing a layer of compressed gas adjacent to the flame front. A mixture with a density higher than that of the initial gas enters the flame front, is heated, and enters into reaction. As a result, a high-amplitude pressure peak is formed at the flame front. An increase in pressure and density at the leading edge of the flame front accelerates the chemical reaction, causing amplification of the compression wave and an exponentially rapid growth of the pressure peak, which 'drags' the flame behind. A high-amplitude compression wave produces a strong shock immediately ahead of the reaction zone, generating a detonation wave. The theory and numerical simulations of the flame acceleration and the new physical mechanism of DDT are in complete agreement with the experimentally observed flame acceleration, shock formation, and DDT in a hydrogen-oxygen gas mixture.

  9. Proven, long-life hydrogen/oxygen thrust chambers for space station propulsion

    NASA Technical Reports Server (NTRS)

    Richter, G. P.; Price, H. G.

    1986-01-01

    The development of the manned space station has necessitated the development of technology related to an onboard auxiliary propulsion system (APS) required to provide for various space station attitude control, orbit positioning, and docking maneuvers. A key component of this onboard APS is the thrust chamber design. To develop the required thrust chamber technology to support the Space Station Program, the NASA Lewis Research Center has sponsored development programs under contracts with Aerojet TechSystems Company and with Bell Aerospace Textron Division of Textron, Inc. During the NASA Lewis sponsored program with Aerojet TechSystems, a 25 lb sub f hydrogen/oxygen thruster has been developed and proven as a viable candidate to meet the needs of the Space Station Program. Likewise, during the development program with Bell Aerospace, a 50 lb sub f hydrogen/oxygen Thrust Chamber has been developed and has demonstrated reliable, long-life expectancy at anticipated space station operating conditions. Both these thrust chambers were based on design criteria developed in previous thruster programs and successfully verified in experimental test programs. Extensive thermal analyses and models were used to design the thrusters to achieve total impulse goals of 2 x 10 to the 6th power lb sub f-sec. Test data for each thruster will be compared to the analytical predictions for the performance and heat transfer characteristics. Also, the results of thrust chamber life verification tests will be presented.

  10. First-Principles Petascale Simulations for Predicting Deflagration to Detonation Transition in Hydrogen-Oxygen Mixtures

    SciTech Connect

    Khokhlov, Alexei; Austin, Joanna; Bacon, C.

    2015-03-02

    Hydrogen has emerged as an important fuel across a range of industries as a means of achieving energy independence and to reduce emissions. DDT and the resulting detonation waves in hydrogen-oxygen can have especially catastrophic consequences in a variety of industrial and energy producing settings related to hydrogen. First-principles numerical simulations of flame acceleration and DDT are required for an in-depth understanding of the phenomena and facilitating design of safe hydrogen systems. The goals of this project were (1) to develop first-principles petascale reactive flow Navier-Stokes simulation code for predicting gaseous high-speed combustion and detonation (HSCD) phenomena and (2) demonstrate feasibility of first-principles simulations of rapid flame acceleration and deflagration-to-detonation transition (DDT) in stoichiometric hydrogen-oxygen mixture (2H2 + O2). The goals of the project have been accomplished. We have developed a novel numerical simulation code, named HSCD, for performing first-principles direct numerical simulations of high-speed hydrogen combustion. We carried out a series of validating numerical simulations of inert and reactive shock reflection experiments in shock tubes. We then performed a pilot numerical simulation of flame acceleration in a long pipe. The simulation showed the transition of the rapidly accelerating flame into a detonation. The DDT simulations were performed using BG/Q Mira at the Argonne National Laboratory, currently the fourth fastest super-computer in the world.

  11. Fully relayed regenerative amplifier

    DOEpatents

    Glass, Alexander J.

    1981-01-01

    A regenerative laser apparatus and method using the optical relay concept to maintain high fill factors, to suppress diffraction effects, and to minimize phase distortions in a regenerative amplifier.

  12. Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    KSC employees, along with Center Director Roy Bridges (second from left), view the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

  13. Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In front of the Headquarters Building at KSC, Center Director Roy Bridges (left) looks at the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by- product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

  14. Temperature distributions of a cesium-seeded hydrogen-oxygen supersonic free jet

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.; Smith, J. M.

    1978-01-01

    The hydrogen-oxygen plasma was generated at combustion chamber pressures ranging from 0.5 to 2.0 megapascals and for various seed ratios (1 to 10 percent). The plasma was observed as the atmospheric exhaust from a Mach 2 rocket test facility. Transverse profiles of the absolute integrated intensity were measured with the optically thin CsI lines (0.5664 and 0.5636 microns) at a range of axial positions downstream of the 5-cm-diameter combustor nozzle exit. Radial profiles of the emission coefficient were obtained from the measured transverse profiles of intensity by Abel inversion. Temperatures were then determined from the emission coefficients for conditions of local thermodynamic equilibrium using particle densities generated by a two-dimensional free jet computer program. Temperature results show the inherent effects of compression and expansion pressure waves characteristic of a free jet exiting from a supersonic nozzle.

  15. Effective thermal conductivities of four metal ceramic composite coatings in hydrogen-oxygen rocket firings

    NASA Technical Reports Server (NTRS)

    Schacht, R. L.; Price, H. G., Jr.; Quentmeyer, R. J.

    1972-01-01

    An experimental investigation was conducted to determine the effective conductivities of four plasma-arc-sprayed, metal-ceramic gradated coatings on hydrogen-oxygen thrust chambers. The effective thermal conductivities were not a function of pressure or oxidant-to-fuel ratio. The various materials that made up these composites do not seem to affect the thermal conductivity values as much as the differences in the thermal conductivities of the parent materials would lead one to expect. Contact resistance evolving from the spraying process seems to be the controlling factor. The thermal conductivities of all the composites tested fell in the range of 0.75 to 7.5 watts per meter kelvin.

  16. Catalysts for initiating the hydrogen-oxygen reaction at 78 K.

    NASA Technical Reports Server (NTRS)

    Jennings, T. J.; Voge, H. H.; Armstrong, W. E.

    1972-01-01

    Catalysts for initiating reaction of hydrogen with oxygen in gas mixtures at temperatures down to 78 K (-195 C) were sought. A rising-temperature reactor was used for detecting onset of reaction. The platinum metals, especially iridium, platinum, and ruthenium, were the most active. With high concentrations of iridium on an alumina support, reaction initiation was observed at -195 C for a helium stream containing 3% hydrogen and 1% oxygen. Best results were obtained when the catalyst had been preheated in hydrogen and cooled in a hydrogen environment before being contacted with oxygen-containing gas. The initiation is interpreted to be the result of transient phenomena which occur when a hydrogen-oxygen mixture contacts an active catalyst. Chemisorption of oxygen and formation of some water, along with water adsorption on the support, serve to raise the temperature to a point where true catalysis can proceed.

  17. Computation of Kinetics for the Hydrogen/Oxygen System Using the Thermodynamic Method

    NASA Technical Reports Server (NTRS)

    Marek, C. John

    1996-01-01

    A new method for predicting chemical rate constants using thermodynamics has been applied to the hydrogen/oxygen system. This method is based on using the gradient of the Gibbs free energy and a single proportionality constant D to determine the kinetic rate constants. Using this method the rate constants for any gas phase reaction can be computed from thermodynamic properties. A modified reaction set for the H/O system is determined. A11 of the third body efficiencies M are taken to be unity. Good agreement was obtained between the thermodynamic method and the experimental shock tube data. In addition, the hydrogen bromide experimental data presented in previous work is recomputed with M's of unity.

  18. Investigation of spontaneous combustion of hydrogen-oxygen mixture using DSMC simulation

    SciTech Connect

    Yang, Chao; Sun, Quanhua

    2014-12-09

    Combustion has been widely studied in the literature, but very little work was focused on the microscopic level. In this paper, the DSMC method is applied to simulate the microscopic behavior of the spontaneous combustion of hydrogen oxygen mixture. It is found that the ignition delay time of the mixture depends on many factors, such as the physical size, temperature, pressure, and dilution. Comparison between DSMC and CFD results shows that more atomic hydrogen is consumed through reaction HO{sub 2}+H→H{sub 2}+O{sub 2} at temperature close to the extended second explosion limit due to localized distribution of reactants, which may indicate the importance of microscopic behavior on low temperature combustion.

  19. Photocatalytic decomposition of humic acids in anoxic aqueous solutions producing hydrogen, oxygen and light hydrocarbons.

    PubMed

    Klauson, Deniss; Budarnaja, Olga; Beltran, Ignacio Castellanos; Krichevskaya, Marina; Preis, Sergei

    2014-01-01

    Photocatalytic water splitting for hydrogen and oxygen production requires sacrificial electron donors, for example, organic compounds. Titanium dioxide catalysts doped with platinum, cobalt, tungsten, copper and iron were experimentally tested for the production of hydrogen, oxygen and low molecular weight hydrocarbons from aqueous solutions of humic substances (HS). Platinum-doped catalyst showed the best results in hydrogen generation, also producing methane, ethene and ethane, whereas the best oxygen production was exhibited by P25, followed by copper--and cobalt-containing photocatalysts. Iron-containing photocatalyst produced carbon monoxide as a major product. HS undergoing anoxic photocatalytic degradation produce hydrogen with minor hydrocarbons, and/or oxygen. It appears that better hydrogen yield is achieved when direct HS splitting takes place, as opposed to HS acting as electron donors for water splitting.

  20. Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    KSC employees, along with Center Director Roy Bridges (second from left), view the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

  1. Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In front of the Headquarters Building at KSC, Center Director Roy Bridges (left) looks at the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by- product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

  2. An Experimental Study of Unconfined Hydrogen/Oxygen and Hydrogen/Air Explosions

    NASA Technical Reports Server (NTRS)

    Richardson, Erin; Skinner, Troy; Blackwood, James; Hays, Michael; Bangham, Mike; Jackson, Austin

    2014-01-01

    Development tests are being conducted to characterize unconfined Hydrogen/air and Hydrogen/Oxygen blast characteristics. Most of the existing experiments for these types of explosions address contained explosions, like shock tubes. Therefore, the Hydrogen Unconfined Combustion Test Apparatus (HUCTA) has been developed as a gaseous combustion test device for determining the relationship between overpressure, impulse, and flame speed at various mixture ratios for unconfined reactions of hydrogen/oxygen and hydrogen/air. The system consists of a central platform plumbed to inject and mix component gasses into an attached translucent bag or balloon while monitoring hydrogen concentration. All tests are ignited with a spark with plans to introduce higher energy ignition sources in the future. Surrounding the platform are 9 blast pressure "Pencil" probes. Two high-speed cameras are used to observe flame speed within the combustion zone. The entire system is raised approx. 6 feet off the ground to remove any ground reflection from the measurements. As of this writing greater than 175 tests have been performed and include Design of Experiments test sets. Many of these early tests have used bags or balloons between approx. 340L and approx. 1850L to quantify the effect of gaseous mixture ratio on the properties of interest. All data acquisition is synchronized between the high-speed cameras, the probes, and the ignition system to observe flame and shock propagation. Successful attempts have been made to couple the pressure profile with the progress of the flame front within the combustion zone by placing a probe within the bag. Overpressure and impulse data obtained from these tests are used to anchor engineering analysis tools, CFD models and in the development of blast and fragment acceleration models.

  3. Regenerative Fuel Cell Test Rig Completed and Operational at Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    2004-01-01

    The NASA Glenn Research Center has completed construction of its first closed-cycle hydrogen-oxygen regenerative fuel cell (RFC). The RFC is an electrochemical system that collects and stores solar energy during the day then releases that energy at night, thus making the Sun's energy available all 24 hours. It consists of a dedicated hydrogen-oxygen fuel cell stack and an electrolyzer stack, the interconnecting plumbing and valves, cooling pumps, water transfer pumps, gas recirculation pumps, phase separators, storage tanks for oxygen (O2) and hydrogen (H2), heat exchangers, isolation valves, pressure regulators, nitrogen purge provisions, instrumentation, and other components. It includes all the equipment required to (1) absorb electrical power from an outside source and store it as pressurized hydrogen and oxygen and (2) make electrical power from the stored gases, saving the product water for reuse during the next cycle.

  4. [Regenerative approach for COPD].

    PubMed

    Kubo, Hiroshi

    2011-10-01

    No treatment to cure of chronic obstructive pulmonary disease (COPD) is available. Regenerative medicine is one of promising areas for this intractable disease. Several reagents and growth factors are known to promote lung regeneration in small animal models. However, regenerative medicines for human lungs are not achieved yet. Recent advances in stem cell biology and tissue engineering have expanded our understanding of lung endogenous stem cells, and this new knowledge provides us with new ideas for future regenerative therapy for lung diseases. Although lungs are the most challenging organ for regenerative medicine, our cumulative knowledge of lung regeneration and of endogenous progenitor cells makes clear the possibilities for regenerative approach to COPD.

  5. Modeling and optimization of a regenerative fuel cell system using the ASPEN process simulator

    NASA Technical Reports Server (NTRS)

    Maloney, Thomas M.; Leibecki, Harold F.

    1990-01-01

    The Hydrogen-Oxygen Regenerative Fuel Cell System was identified as a key component for energy storage in support of future lunar missions. Since the H2-O2 regenerative electrochemical conversion technology has not yet been tested in space applications, it is necessary to implement predictive techniques to develop initial feasible system designs. The ASPEN simulation software furnishes a constructive medium for analyzing and optimizing such systems. A rudimentary regenerative fuel cell system design was examined using the ASPEN simulator and this modular approach allows for easy addition of supplementary ancillary components and easy integration with life support systems. The modules included in the preliminary analyses may serve as the fundamental structure for more complicated energy storage systems.

  6. Modeling and optimization of a regenerative fuel cell system using the ASPEN process simulator

    NASA Technical Reports Server (NTRS)

    Maloney, Thomas M.; Leibecki, Harold F.

    1990-01-01

    The Hydrogen-Oxygen Regenerative Fuel Cell System was identified as a key component for energy storage in support of future lunar missions. Since the H2-O2 regenerative electrochemical conversion technology has not yet been tested in space applications, it is necessary to implement predictive techniques to develop initial feasible system designs. The ASPEN simulation software furnishes a constructive medium for analyzing and optimizing such systems. A rudimentary regenerative fuel cell system design was examined using the ASPEN simulator and this modular approach allows for easy addition of supplementary ancillary components and easy integration with life support systems. The modules included in the preliminary analyses may serve as the fundamental structure for more complicated energy storage systems.

  7. Modeling and optimization of a regenerative fuel cell system using the ASPEN process simulator

    NASA Technical Reports Server (NTRS)

    Maloney, Thomas M.; Leibecki, Harold F.

    1990-01-01

    The Hydrogen-Oxygen Regenerative Fuel Cell System was identified as a key component for energy storage in support of future lunar missions. Since the H2-O2 regenerative electrochemical conversion technology has not yet been tested in space applications, it is necessary to implement predictive techniques to develop initial feasible system designs. The ASPEN simulation software furnishes a constructive medium for analyzing and for optimizing such systems. A rudimentary regenerative fuel cell system design was examined using the ASPEN simulator and this modular approach allows for easy addition of supplementary ancillary components and easy integration with life support systems. The modules included in the preliminary analyses may serve as the fundamental structure for more complicated energy storage systems.

  8. Computer simulation of thermal modelling of alkaline hydrogen/oxygen fuel cells

    NASA Astrophysics Data System (ADS)

    Baumann, A.; Hauff, S.; Bolwin, K.

    1991-11-01

    An essential problem connected with the operation of regenerative fuel cell systems in space is the rejection of waste heat, produced mainly during discharging the regenerative fuel cell. The intention of this investigation was to gain a better understanding of the heat generation and heat rejection mechanism in alkaline fuel cells by performing detailed thermal modeling of a single cell stack. In particular, spatial temperature profiles within the fuel cell stack and the start-up behavior of the cells were predicted. Furthermore a model simulation of an emergency situation due to a partial failure of the coolant circuit was performed and theoretically temperature versus time curves were given for restarting the cooling.

  9. Cryogenic reactant storage for lunar base regenerative fuel cells

    NASA Technical Reports Server (NTRS)

    Kohout, Lisa L.

    1989-01-01

    There are major advantages to be gained by integrating a cryogenic reactant storage system with a hydrogen-oxygen regenerative fuel cell (RFC) to provide on-site electrical power during the lunar night. Although applicable to any power system using hydrogen-oxygen RFC's for energy storage, cryogenic reactant storage offers a significant benefit whenever the sun/shade cycle and energy storage period approach hundreds of hours. For solar power installations on the moon, cryogenic reactant storage reduces overall specific mass and meteoroid vulnerability of the system. In addition, it offers synergistic benefits to on-site users, such as availability of primary fuel cell reactants for surface rover vehicles and cryogenic propellants for OTV's. The integration involves processing and storing the RFC reactant streams as cryogenic liquids rather than pressurized gases, so that reactant containment (tankage per unit mass of reactants) can be greatly reduced. Hydrogen-oxygen alkaline RFC's, GaAs photovoltaic (PV) arrays, and space cryogenic processing/refrigeration technologies are assumed to be available for the conceptual system design. Advantages are demonstrated by comparing the characteristics of two power system concepts: a conventional lunar surface PV/RFC power system using pressurized gas storage in SOA filament wound pressure vessels and, that same system with gas liquefaction and storage replacing the pressurized storage. Comparisons are made at 20 and 250 kWe. Although cryogenic storage adds a processing plant (drying and liquefaction) to the system plus 30 percent more solar array to provide processing power, the approximate order of magnitude reduction in tankage mass, confirmed by this analysis, results in a reduction in overall total system mass of approximately 50 percent.

  10. Cryogenic reactant storage for lunar base regenerative fuel cells

    NASA Astrophysics Data System (ADS)

    Kohout, Lisa L.

    1989-02-01

    There are major advantages to be gained by integrating a cryogenic reactant storage system with a hydrogen-oxygen regenerative fuel cell (RFC) to provide on-site electrical power during the lunar night. Although applicable to any power system using hydrogen-oxygen RFC's for energy storage, cryogenic reactant storage offers a significant benefit whenever the sun/shade cycle and energy storage period approach hundreds of hours. For solar power installations on the moon, cryogenic reactant storage reduces overall specific mass and meteoroid vulnerability of the system. In addition, it offers synergistic benefits to on-site users, such as availability of primary fuel cell reactants for surface rover vehicles and cryogenic propellants for OTV's. The integration involves processing and storing the RFC reactant streams as cryogenic liquids rather than pressurized gases, so that reactant containment (tankage per unit mass of reactants) can be greatly reduced. Hydrogen-oxygen alkaline RFC's, GaAs photovoltaic (PV) arrays, and space cryogenic processing/refrigeration technologies are assumed to be available for the conceptual system design. Advantages are demonstrated by comparing the characteristics of two power system concepts: a conventional lunar surface PV/RFC power system using pressurized gas storage in SOA filament wound pressure vessels and, that same system with gas liquefaction and storage replacing the pressurized storage. Comparisons are made at 20 and 250 kWe. Although cryogenic storage adds a processing plant (drying and liquefaction) to the system plus 30 percent more solar array to provide processing power, the approximate order of magnitude reduction in tankage mass, confirmed by this analysis, results in a reduction in overall total system mass of approximately 50 percent.

  11. Cryogenic reactant storage for lunar base regenerative fuel cells

    NASA Astrophysics Data System (ADS)

    Kohout, Lisa L.

    There are major advantages to be gained by integrating a cryogenic reactant storage system with a hydrogen-oxygen regenerative fuel cell (RFC) to provide on-site electrical power during the lunar night. Although applicable to any power system using hydrogen-oxygen RFC's for energy storage, cryogenic reactant storage offers a significant benefit whenever the sun/shade cycle and energy storage period approach hundreds of hours. For solar power installations on the moon, cryogenic reactant storage reduces overall specific mass and meteoroid vulnerability of the system. In addition, it offers synergistic benefits to on-site users, such as availability of primary fuel cell reactants for surface rover vehicles and cryogenic propellants for OTV's. The integration involves processing and storing the RFC reactant streams as cryogenic liquids rather than pressurized gases, so that reactant containment (tankage per unit mass of reactants) can be greatly reduced. Hydrogen-oxygen alkaline RFC's, GaAs photovoltaic (PV) arrays, and space cryogenic processing/refrigeration technologies are assumed to be available for the conceptual system design. Advantages are demonstrated by comparing the characteristics of two power system concepts: a conventional lunar surface PV/RFC power system using pressurized gas storage in SOA filament wound pressure vessels and, that same system with gas liquefaction and storage replacing the pressurized storage. Comparisons are made at 20 and 250 kWe. Although cryogenic storage adds a processing plant (drying and liquefaction) to the system plus 30 percent more solar array to provide processing power, the approximate order of magnitude reduction in tankage mass, confirmed by this analysis, results in a reduction in overall total system mass of approximately 50 percent.

  12. Cryogenic reactant storage for lunar base regenerative fuel cells

    NASA Technical Reports Server (NTRS)

    Kohout, Lisa L.

    1989-01-01

    There are major advantages to be gained by integrating a cryogenic reactant storage system with a hydrogen-oxygen regenerative fuel cell (RFC) to provide on-site electrical power during the lunar night. Although applicable to any power system using hydrogen-oxygen RFC's for energy storage, cryogenic reactant storage offers a significant benefit whenever the sun/shade cycle and energy storage period approach hundreds of hours. For solar power installations on the moon, cryogenic reactant storage reduces overall specific mass and meteoroid vulnerability of the system. In addition, it offers synergistic benefits to on-site users, such as availability of primary fuel cell reactants for surface rover vehicles and cryogenic propellants for OTV's. The integration involves processing and storing the RFC reactant streams as cryogenic liquids rather than pressurized gases, so that reactant containment (tankage per unit mass of reactants) can be greatly reduced. Hydrogen-oxygen alkaline RFC's, GaAs photovoltaic (PV) arrays, and space cryogenic processing/refrigeration technologies are assumed to be available for the conceptual system design. Advantages are demonstrated by comparing the characteristics of two power system concepts: a conventional lunar surface PV/RFC power system using pressurized gas storage in SOA filament wound pressure vessels and, that same system with gas liquefaction and storage replacing the pressurized storage. Comparisons are made at 20 and 250 kWe. Although cryogenic storage adds a processing plant (drying and liquefaction) to the system plus 30 percent more solar array to provide processing power, the approximate order of magnitude reduction in tankage mass, confirmed by this analysis, results in a reduction in overall total system mass of approximately 50 percent.

  13. Vibrational non-equilibrium in the hydrogen-oxygen reaction. Comparison with experiment

    NASA Astrophysics Data System (ADS)

    Skrebkov, Oleg V.

    2015-03-01

    A theoretical model is proposed for the chemical and vibrational kinetics of hydrogen oxidation based on consistent accounting of the vibrational non-equilibrium of the HO2 radical that forms as a result of the bimolecular recombination H+O2 → HO2. In the proposed model, the chain branching H+O2 = O+OH and inhibiting H+O2+M = HO2+M formal reactions are treated (in the terms of elementary processes) as a single multi-channel process of forming, intramolecular energy redistribution between modes, relaxation, and unimolecular decay of the comparatively long-lived vibrationally excited HO2 radical, which is able to react and exchange energy with the other components of the mixture. The model takes into account the vibrational non-equilibrium of the starting (primary) H2 and O2 molecules, as well as the most important molecular intermediates HO2, OH, O2(1Δ), and the main reaction product H2O. It is shown that the hydrogen-oxygen reaction proceeds in the absence of vibrational equilibrium, and the vibrationally excited HO2(v) radical acts as a key intermediate in a fundamentally important chain branching process and in the generation of electronically excited species O2(1Δ), O(1D), and OH(2Σ+). The calculated results are compared with the shock tube experimental data for strongly diluted H2-O2 mixtures at 1000 < T < 2500 K, 0.5 < p < 4 atm. It is demonstrated that this approach is promising from the standpoint of reconciling the predictions of the theoretical model with experimental data obtained by different authors for various compositions and conditions using different methods. For T < 1500 K, the nature of the hydrogen-oxygen reaction is especially non-equilibrium, and the vibrational non-equilibrium of the HO2 radical is the essence of this process. The quantitative estimation of the vibrational relaxation characteristic time of the HO2 radical in its collisions with H2 molecules has been obtained as a result of the comparison of different experimental data on

  14. Final Report: Cathode Catalysis in Hydrogen/Oxygen Fuel Cells: New Catalysts, Mechanism, and Characterization

    SciTech Connect

    Gewirth, Andrew A.; Kenis, Paul J.; Nuzzo, Ralph G.; Rauchfuss, Thomas B.

    2016-01-18

    In this research, we prosecuted a comprehensive plan of research directed at developing new catalysts and new understandings relevant to the operation of low temperature hydrogen-oxygen fuel cells. The focal point of this work was one centered on the Oxygen Reduction Reaction (ORR), the electrochemical process that most fundamentally limits the technological utility of these environmentally benign energy conversion devices. Over the period of grant support, we developed new ORR catalysts, based on Cu dimers and multimers. In this area, we developed substantial new insight into design rules required to establish better ORR materials, inspired by the three-Cu active site in laccase which has the highest ORR onset potential of any material known. We also developed new methods of characterization for the ORR on conventional (metal-based) catalysts. Finally, we developed a new platform to study the rate of proton transfer relevant to proton coupled electron transfer (PCET) reactions, of which the ORR is an exemplar. Other aspects of work involved theory and prototype catalyst testing.

  15. Qualitative Flow Visualization of a 110-N Hydrogen/Oxygen Laboratory Model Thruster

    NASA Technical Reports Server (NTRS)

    deGroot, Wim A.; McGuire, Thomas J.; Schneider, Steven J.

    1997-01-01

    The flow field inside a 110 N gaseous hydrogen/oxygen thruster was investigated using an optically accessible, two-dimensional laboratory test model installed in a high altitude chamber. The injector for this study produced an oxidizer-rich core flow, which was designed to fully mix and react inside a fuel-film sleeve insert before emerging into the main chamber section, where a substantial fuel film cooling layer was added to protect the chamber wall. Techniques used to investigate the flow consisted of spontaneous Raman spectra measurements, visible emission imaging, ultraviolet hydroxyl spectroscopy, and high speed schlieren imaging. Experimental results indicate that the oxygen rich core flow continued to react while emerging from the fuel-film sleeve, suggesting incomplete mixing of the hydrogen in the oxygen rich core flow. Experiments also showed that the fuel film cooling protective layer retained its integrity throughout the straight section of the combustion chamber. In the converging portion of the chamber, however, a turbulent reaction zone near the wall destroyed the integrity of the film layer, a result which implies that a lower contraction angle may improve the fuel film cooling in the converging section and extend the hardware lifetime.

  16. Pulsed laser Rayleigh scattering diagnostic for hydrogen/oxygen rocket exit plane flowfield velocimetry

    NASA Technical Reports Server (NTRS)

    Zupanc, Frank J.

    1993-01-01

    A Doppler-resolved, pulsed laser Rayleigh scattering diagnostic has been developed to obtain local flowfield velocity measurements at the exit plane of a low thrust hydrogen/oxygen rocket engine operating in a high-altitude test facility. Fiberoptic signal collection was employed to obtain the forescatter and backscatter Doppler shifts necessary to resolve the axial and radial velocity components. A radial profile was obtained by traversing the collection probes along the beam path at the nozzle exit. The results are compared with theoretical predictions from a full Navier-Stokes model (RK/RPLUS). Significant discrepancies between the measured and predicted axial velocity profiles are observed, in terms of both magnitude and character. Radial velocity measurements exhibit excellent agreement with predictions near the centerline but show some departure off-axis. The discrepancies between theory and experiment are potentially the result of enhanced mixing between the core and fuel-film region beyond that predicted, and/or flow stratification between the hydrogen and oxygen injected into the central core region.

  17. Laser Rayleigh and Raman Diagnostics for Small Hydrogen/oxygen Rockets

    NASA Technical Reports Server (NTRS)

    Degroot, Wilhelmus A.; Zupanc, Frank J.

    1993-01-01

    Localized velocity, temperature, and species concentration measurements in rocket flow fields are needed to evaluate predictive computational fluid dynamics (CFD) codes and identify causes of poor rocket performance. Velocity, temperature, and total number density information have been successfully extracted from spectrally resolved Rayleigh scattering in the plume of small hydrogen/oxygen rockets. Light from a narrow band laser is scattered from the moving molecules with a Doppler shifted frequency. Two components of the velocity can be extracted by observing the scattered light from two directions. Thermal broadening of the scattered light provides a measure of the temperature, while the integrated scattering intensity is proportional to the number density. Spontaneous Raman scattering has been used to measure temperature and species concentration in similar plumes. Light from a dye laser is scattered by molecules in the rocket plume. Raman spectra scattered from major species are resolved by observing the inelastically scattered light with linear array mounted to a spectrometer. Temperature and oxygen concentrations have been extracted by fitting a model function to the measured Raman spectrum. Results of measurements on small rockets mounted inside a high altitude chamber using both diagnostic techniques are reported.

  18. Laser Rayleigh and Raman diagnostics for small hydrogen/oxygen rockets

    NASA Astrophysics Data System (ADS)

    Degroot, Wilhelmus A.; Zupanc, Frank J.

    1993-01-01

    Localized velocity, temperature, and species concentration measurements in rocket flow fields are needed to evaluate predictive computational fluid dynamics (CFD) codes and identify causes of poor rocket performance. Velocity, temperature, and total number density information have been successfully extracted from spectrally resolved Rayleigh scattering in the plume of small hydrogen/oxygen rockets. Light from a narrow band laser is scattered from the moving molecules with a Doppler shifted frequency. Two components of the velocity can be extracted by observing the scattered light from two directions. Thermal broadening of the scattered light provides a measure of the temperature, while the integrated scattering intensity is proportional to the number density. Spontaneous Raman scattering has been used to measure temperature and species concentration in similar plumes. Light from a dye laser is scattered by molecules in the rocket plume. Raman spectra scattered from major species are resolved by observing the inelastically scattered light with linear array mounted to a spectrometer. Temperature and oxygen concentrations have been extracted by fitting a model function to the measured Raman spectrum. Results of measurements on small rockets mounted inside a high altitude chamber using both diagnostic techniques are reported.

  19. Laser Rayleigh and Raman diagnostics for small hydrogen/oxygen rockets

    NASA Astrophysics Data System (ADS)

    de Groot, Wim A.; Zupanc, Frank J.

    1993-05-01

    Localized velocity, temperature, and species concentration measurements in rocket flow fields are needed to evaluate predictive computational fluid dynamics (CFD) codes and identify causes of poor rocket performance. Velocity, temperature, and total number density information have been successfully extracted from spectrally resolved Rayleigh scattering in the plume of small hydrogen/oxygen rockets. Light from a narrow band laser is scattered from the moving molecules with a Doppler shifted frequency. Two components of the velocity can be extracted by observing the scattered light from two directions. Thermal broadening of the scattered light provides a measure of the temperature, while the integrated scattering intensity is proportional to the number density. Spontaneous Raman scattering has been used to measure temperature and species concentration in similar plumes. Light from a dye laser is scattered by molecules in the rocket plume. Raman spectra scattered from major species are resolved by observing the inelastically scattered light with a linear array mounted to a spectrometer. Temperature and oxygen concentrations have been extracted by fitting a model function to the measured Raman spectrum. Results of measurements on small rockets mounted inside a high altitude chamber using both diagnostic techniques are reported.

  20. A Study of Oxidation of Hydrogen Based on Flashback of Hydrogen-Oxygen-Nitrogen Burner Flames

    NASA Technical Reports Server (NTRS)

    Fine, Burton D.

    1959-01-01

    The flashback of hydrogen-oxygen-nitrogen flames was studied as a function of pressure, burner diameter, equivalence ratio, and oxidant strength. The results were treated on the assumption that the product of the critical boundary velocity gradient for flashback and the initial concentration of that reactant which is not in excess is proportional to a mean reaction rate associated with the flame zone. It was further assumed that this reaction rate can be expressed in terms of initial concentrations and flame temperature. Measurements at constant flame temperature yield orders of reaction with respect to hydrogen and oxygen. These do not vary with flame temperature. Measurements in which pressure is varied for several values of oxidant strength at constant equivalence ratio yield a total order of reaction and a function describing the dependence of the mean reaction rate on flame temperature. The total reaction order is independent of flame temperature and equal to the sum of the orders for hydrogen and oxygen. The dependence of the reaction rate on flame temperature cannot be described by a constant activation energy. The activation energy obtained apparently increases with flame temperature. Flashback results can be described by a single rate constant which is independent of equivalence ratio. Values were estimated for this rate constant as a function of flame temperature.

  1. Reference concepts for a space-based hydrogen-oxygen combustion, turboalternator, burst power system

    SciTech Connect

    Edenburn, M.W.

    1990-07-01

    This report describes reference concepts for a hydrogen-oxygen combustion, turboalternator power system that supplies power during battle engagement to a space-based, ballistic missile defense platform. All of the concepts are open''; that is, they exhaust hydrogen or a mixture of hydrogen and water vapor into space. We considered the situation where hydrogen is presumed to be free to the power system because it is also needed to cool the platform's weapon and the situation where hydrogen is not free and its mass must be added to that of the power system. We also considered the situation where water vapor is an acceptable exhaust and the situation where it is not. The combination of these two sets of situations required four different power generation systems, and this report describes each, suggests parameter values, and estimates masses for each of the four. These reference concepts are expected to serve as a baseline'' to which other types of power systems can be compared, and they are expected to help guide technology development efforts in that they suggest parameter value ranges that will lead to optimum system designs. 7 refs., 18 figs., 5 tabs.

  2. Unitized regenerative fuel cell system

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth A. (Inventor)

    2008-01-01

    A Unitized Regenerative Fuel Cell system uses heat pipes to convey waste heat from the fuel cell stack to the reactant storage tanks. The storage tanks act as heat sinks/sources and as passive radiators of the waste heat from the fuel cell stack. During charge up, i.e., the electrolytic process, gases are conveyed to the reactant storage tanks by way of tubes that include dryers. Reactant gases moving through the dryers give up energy to the cold tanks, causing water vapor in with the gases to condense and freeze on the internal surfaces of the dryer. During operation in its fuel cell mode, the heat pipes convey waste heat from the fuel cell stack to the respective reactant storage tanks, thereby heating them such that the reactant gases, as they pass though the respective dryers on their way to the fuel cell stacks retrieve the water previously removed.

  3. SULFUR DIOXIDE - SULFUR TRIOXIDE REGENERATIVE FUEL CELL RESEARCH

    DTIC Science & Technology

    The thermodynamics and electrolytic characteristics are discussed of an SO2-SO3 regenerative, closed-cycle fuel cell , and summarizes the electrolytic...electrochemical, and phase separation research conducted during a study program to determine the practicability of such a fuel cell . The...experimental results obtained were at such wide variance with the theoretical concept that it became apparent that a fuel cell of this type is not feasible. (Author)

  4. Technical report on galvanic cells with fused-salt electrolytes

    NASA Technical Reports Server (NTRS)

    Cairns, E. J.; Crouthamel, C. E.; Fischer, A. K.; Foster, M. S.; Hesson, J. C.; Johnson, C. E.; Shimotake, H.; Tevebaugh, A. D.

    1969-01-01

    Technical report is presented on sodium and lithium cells using fused salt electrolytes. It includes a discussion of the thermally regenerative galvanic cell and the secondary bimetallic cell for storage of electricity.

  5. The TMI Regenerative Solid Oxide Fuel Cell

    NASA Technical Reports Server (NTRS)

    Cable, Thomas L.; Ruhl, Robert C.; Petrik, Michael

    1996-01-01

    Energy storage and production in space requires rugged, reliable hardware which minimizes weight, volume, and maintenance while maximizing power output and usable energy storage. Systems generally consist of photovoltaic solar arrays which operate (during sunlight cycles) to provide system power and regenerate fuel (hydrogen) via water electrolysis and (during dark cycles) fuel cells convert hydrogen into electricity. Common configurations use two separate systems (fuel cell and electrolyzer) in conjunction with photovoltaic cells. Reliability, power to weight and power to volume ratios could be greatly improved if both power production (fuel cells) and power storage (electrolysis) functions can be integrated into a single unit. The solid oxide fuel cell (SOFC) based design integrates fuel cell and electrolyzer functions and potentially simplifies system requirements. The integrated fuel cell/electrolyzer design also utilizes innovative gas storage concepts and operates like a rechargeable 'hydrogen-oxygen battery'. Preliminary research has been completed on improved H2/H20 electrode (SOFC anode/electrolyzer cathode) materials for regenerative fuel cells. Tests have shown improved cell performance in both fuel and electrolysis modes in reversible fuel cell tests. Regenerative fuel cell efficiencies, ratio of power out (fuel cell mode) to power in (electrolyzer mode), improved from 50 percent using conventional electrode materials to over 80 percent. The new materials will allow a single SOFC system to operate as both the electolyzer and fuel cell. Preliminary system designs have also been developed to show the technical feasibility of using the design for space applications requiring high energy storage efficiencies and high specific energy. Small space systems also have potential for dual-use, terrestrial applications.

  6. High temperature solid oxide regenerative fuel cell for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1987-01-01

    A hydrogen-oxygen regenerative fuel cell energy storage system based on high temperature solid oxide fuel cell technology is discussed which has application to darkside energy storage for solar photovoltaics. The forward and reverse operating cycles are described, and heat flow, mass, and energy balance data are presented to characterize the system's performance and the variation of performance with changing reactant storage pressure. The present system weighs less than nickel hydrogen battery systems after 0.7 darkside operation, and it maintains a specific weight advantage over radioisotope generators for discharge periods up to 72 hours.

  7. High temperature solid oxide regenerative fuel cell for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1987-01-01

    A hydrogen-oxygen regenerative fuel cell energy storage system based on high temperature solid oxide fuel cell technology is discussed which has application to darkside energy storage for solar photovoltaics. The forward and reverse operating cycles are described, and heat flow, mass, and energy balance data are presented to characterize the system's performance and the variation of performance with changing reactant storage pressure. The present system weighs less than nickel hydrogen battery systems after 0.7 darkside operation, and it maintains a specific weight advantage over radioisotope generators for discharge periods up to 72 hours.

  8. Regenerative (Regen) ECLSS Operations Water Balance

    NASA Technical Reports Server (NTRS)

    Tobias, Barry

    2010-01-01

    In November 2008, the Water Regenerative System racks were launched aboard Space Shuttle flight, STS-126 (ULF2) and installed and activated on the International Space Station (ISS). These racks, consisting of the Water Processor Assembly (WPA) and Urine Processor Assembly (UPA), completed the installation of the Regenerative (Regen) ECLSS systems which includes the Oxygen Generator Assembly (OGA) that was launched 2 years prior. With the onset of active water management on the US segment of the ISS, a new operational concept was required, that of "water balance." Even more recently, in 2010 the Sabatier system came online which converts H2 and CO2 into water and methane. The Regen ECLSS systems accept condensation from the atmosphere, urine from crew, and processes that fluid via various means into potable water which is used for crew drinking, building up skip-cycle water inventory, and water for electrolysis to produce oxygen. Specification rates of crew urine output, condensate output, O2 requirements, toilet flush water and drinking needs are well documented and used as a general plan when Regen ECLSS came online. Spec rates are useful in long term planning, however, daily or weekly rates are dependent on a number of variables. The constantly changing rates created a new challenge for the ECLSS flight controllers, who are responsible for operating the ECLSS systems onboard ISS. This paper will review the various inputs to rate changes and inputs to planning events, including but not limited to; crew personnel makeup, Regen ECLSS system operability, vehicle traffic, water containment availability, and Carbon Dioxide Removal Assembly (CDRA) capability. Along with the inputs that change the various rates, the paper will review the different systems, their constraints and finally the operational means by which flight controllers manage this new challenge of "water balance."

  9. Hydrogen-oxygen auxiliary propulsion for the space shuttle. Volume 1: High pressure thrusters

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Technology for long life, high performing, gaseous hydrogen-gaseous oxygen rocket engines suitable for auxiliary propulsion was provided by a combined analytical and experimental program. Propellant injectors, fast response valves, igniters, and regeneratively and film-cooled thrust chambers were tested over a wide range of operating conditions. Data generated include performance, combustion efficiency, thermal characteristics film cooling effectiveness, dynamic response in pulsing, and cycle life limitations.

  10. Regenerative medicine blueprint.

    PubMed

    Terzic, Andre; Harper, C Michel; Gores, Gregory J; Pfenning, Michael A

    2013-12-01

    Regenerative medicine, a paragon of future healthcare, holds unprecedented potential in extending the reach of treatment modalities for individuals across diseases and lifespan. Emerging regenerative technologies, focused on structural repair and functional restoration, signal a radical transformation in medical and surgical practice. Regenerative medicine is poised to provide innovative solutions in addressing major unmet needs for patients, ranging from congenital disease and trauma to degenerative conditions. Realization of the regenerative model of care predicates a stringent interdisciplinary paradigm that will drive validated science into standardized clinical options. Designed as a catalyst in advancing rigorous new knowledge on disease causes and cures into informed delivery of quality care, the Mayo Clinic regenerative medicine blueprint offers a patient-centered, team-based strategy that optimizes the discovery-translation-application roadmap for the express purpose of science-supported practice advancement.

  11. Polymer Electrolytes

    NASA Astrophysics Data System (ADS)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  12. Alkaline regenerative fuel cell systems for energy storage

    SciTech Connect

    Schubert, F.H.; Reid, M.A.; Martin, R.E.

    1981-01-01

    This paper presents the results of a preliminary design study of a Regenerative Fuel Cell Energy Storage system for application to future low-earth orbit space missions. This high energy density storage system is based on state-of-the-art alkaline electrolyte cell technology and incorporates dedicated fuel cell and electrolysis cell modules. 11 refs.

  13. Transport dynamics of a high-power-density matrix-type hydrogen-oxygen fuel cell

    NASA Technical Reports Server (NTRS)

    Prokopius, P. R.; Hagedorn, N. H.

    1974-01-01

    Experimental transport dynamics tests were made on a space power fuel cell of current design. Various operating transients were introduced and transport-related response data were recorded with fluidic humidity sensing instruments. Also, sampled data techniques were developed for measuring the cathode-side electrolyte concentration during transient operation.

  14. Regenerative Hydride Heat Pump

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1992-01-01

    Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

  15. The Path of Carbon in Photosynthesis IX. Photosynthesis, Photoreduction, and the Hydrogen-Oxygen-Carbon Dioxide Dark Reaction

    DOE R&D Accomplishments Database

    Badin, E. J.; Calvin, M.

    1950-02-01

    A comparison of the rates of fixation of Carbon 14 dioxide in algae for the processes of photosynthesis, photoreduction and the hydrogen-oxygen-carbon dioxide dark reaction has been made. For the same series of experiments, rates of incorporation of tracer carbon into the separate soluble components using the radiogram method have been determined. The mechanism of carbon dioxide uptake has been shown to occur via two distinct paths. In all cases studied, essentially the same compounds appear radioactive. The distribution with time, however, differs markedly.

  16. A mathematical model of the maximum power density attainable in an alkaline hydrogen/oxygen fuel cell

    NASA Technical Reports Server (NTRS)

    Kimble, Michael C.; White, Ralph E.

    1991-01-01

    A mathematical model of a hydrogen/oxygen alkaline fuel cell is presented that can be used to predict the polarization behavior under various power loads. The major limitations to achieving high power densities are indicated and methods to increase the maximum attainable power density are suggested. The alkaline fuel cell model describes the phenomena occurring in the solid, liquid, and gaseous phases of the anode, separator, and cathode regions based on porous electrode theory applied to three phases. Fundamental equations of chemical engineering that describe conservation of mass and charge, species transport, and kinetic phenomena are used to develop the model by treating all phases as a homogeneous continuum.

  17. Hydrogen/Oxygen Propellant Densifier Using a Two-Stage Pulse Tube Cryocooler

    NASA Astrophysics Data System (ADS)

    Nguyen, C.; Yeckley, A.; Culler, A.; Haberbusch, M.; Radebaugh, R.

    2004-06-01

    A unique, patent pending, thermoacoustic propellant densifier, that simultaneously densifies liquid hydrogen and liquid oxygen propellants for aerospace vehicles is introduced. The thermoacoustic densifier consists of a two-stage pulse tube cryocooler that operates at 30 Hz using helium as the working fluid. The extremely reliable pulse tube has no moving parts, is water cooled, and is acoustically driven. The pulse tube has been driven by a Thermoacoustic Stirling Heat Engine (TASHE) and a linear flexure bearing compressor. A laboratory prototype was designed, fabricated, and tested at the Sierra Lobo, Inc. facility in Milan, Ohio. Unique design features include a removable 2nd stage for easy testing of low temperature regenerator materials and an advanced aftercooler design geometry. A system description will be presented and experimental data of the pulse tube performance will be compared with REGEN 3.2 and other analytical predictions.

  18. Internal voltage control of hydrogen-oxygen fuel cells: Feasibility study

    NASA Technical Reports Server (NTRS)

    Prokopius, P. R.

    1975-01-01

    An experimental study was conducted to assess the feasibility of internal voltage regulation of fuel cell systems. Two methods were tested. In one, reactant partial pressure was used as the voltage control parameter and in the other reactant total pressure was used for control. Both techniques were breadboarded and tested on a single alkaline-electrolyte fuel cell. Both methods were found to be possible forms of regulation, however, of the two the total pressure technique would be more efficient, simpler to apply and would provide better transient characteristics.

  19. Regenerative similariton laser

    NASA Astrophysics Data System (ADS)

    North, Thibault; Brès, Camille-Sophie

    2016-05-01

    Self-pulsating lasers based on cascaded reshaping and reamplification (2R) are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration.

  20. Regenerative Life Support Evaluation

    NASA Technical Reports Server (NTRS)

    Kleiner, G. N.; Thompson, C. D.

    1977-01-01

    This paper describes the development plan and design concept of the Regenerative Life Support Evaluation (RLSE) planned for flight testing in the European Space Agency Spacelab. The development plan encompasses the ongoing advanced life support subsystem and a systems integration effort to evolve concurrently subsystem concepts that perform their function and can be integrated with other subsystems in a flight demonstration of a regenerative life support system. The design concept for RLSE comprises water-electrolysis O2 generation, electrochemically depolarized CO2 removal, and Sabatier CO2 reduction for atmosphere regeneration, urine vapor-compression distillation, and wash-water hyperfiltration for waste-water recovery. The flight demonstration by RLSE is an important step in qualifying the regenerative concepts for life support in space stations.

  1. Regenerative Life Support Evaluation

    NASA Technical Reports Server (NTRS)

    Kleiner, G. N.; Thompson, C. D.

    1977-01-01

    This paper describes the development plan and design concept of the Regenerative Life Support Evaluation (RLSE) planned for flight testing in the European Space Agency Spacelab. The development plan encompasses the ongoing advanced life support subsystem and a systems integration effort to evolve concurrently subsystem concepts that perform their function and can be integrated with other subsystems in a flight demonstration of a regenerative life support system. The design concept for RLSE comprises water-electrolysis O2 generation, electrochemically depolarized CO2 removal, and Sabatier CO2 reduction for atmosphere regeneration, urine vapor-compression distillation, and wash-water hyperfiltration for waste-water recovery. The flight demonstration by RLSE is an important step in qualifying the regenerative concepts for life support in space stations.

  2. Summary of: Regenerative endodontics.

    PubMed

    Clark, Stephen J

    2014-03-01

    Significant advances in our understanding of the biological processes involved in tooth development and repair at the cellular and molecular levels have underpinned the newly emerging area of regenerative endodontics. Development of treatment protocols based on exploiting the natural wound healing properties of the dental pulp and applying tissue engineering principles has allowed reporting of case series showing preservation of tissue vitality and apexogenesis. To review current case series reporting regenerative endodontics. Current treatment approaches tend to stimulate more reparative than regenerative responses in respect of the new tissue generated, which often does not closely resemble the physiological structure of dentine-pulp. However, despite these biological limitations, such techniques appear to offer significant promise for improved treatment outcomes. Improved biological outcomes will likely emerge from the many experimental studies being reported and will further contribute to improvements in clinical treatment protocols.

  3. Microscale Regenerative Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2006-01-01

    The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

  4. Electrolytic dissolver

    DOEpatents

    Wheelwright, E.J.; Fox, R.D.

    1975-08-26

    This patent related to an electrolytic dissolver wherein dissolution occurs by solution contact including a vessel of electrically insulative material, a fixed first electrode, a movable second electrode, means for insulating the electrodes from the material to be dissolved while permitting a free flow of electrolyte therebetween, means for passing a direct current between the electrodes and means for circulating electrolyte through the dissolver. (auth)

  5. Electrolytic cell

    NASA Astrophysics Data System (ADS)

    Bullock, J. S.; Hale, B. D.

    1984-09-01

    An apparatus is described for the separation of the anolyte and the catholyte during electrolysis. The electrolyte flows through an electrolytic cell between the oppositely charged electrodes. The cell is equipped with a wedge-shaped device, the tapered end is located between the electrodes on the effluent side of the cell. The wedge diverts the flow of the electrolyte to either side of the wedge, substantially separating the anolyte and the catholyte.

  6. Integrated regenerative fuel cell experimental evaluation

    NASA Technical Reports Server (NTRS)

    Martin, Ronald E.

    1990-01-01

    An experimental test program was conducted to investigate the performance characteristics of an integrated regenerative fuel cell (IRFC) concept. The IRFC consists of a separate fuel cell unit and electrolysis cell unit in the same structure, with internal storage of fuel cell product water and external storage of electrolysis cell produced hydrogen and oxygen. The fuel cell unit incorporates an enhanced Orbiter-type cell capable of improved performance at reduced weight. The electrolysis cell features a NiCo2O4 catalyst oxygen evolution eletrode with a porous Teflon cover to retard electrolyte loss. Six complete IRFC assemblies were assembled and performance tested at an operating temperature of 200 F (93.3 C) and reactant pressures up to 170 psia (117.2 n/cu cm) on IRFC No. 4. Anomalous pressure charge/discharge characteristics were encountered during performance evaluation. A reversible fuel cell incorporating a proprietary bi-functional oxygen electrode operated satisfactory at 200 F (93.3 C) at reactant pressures up to 50 psia (41.4 n/cu cm) as a regenerative fuel cell for one cycle, before developing an electrical short in the fuel cell mode. Electrolysis cell 300-hour endurance tests demonstrated the electrolyte retention capability of the electrode Teflon cover and the performance stability of the bi-functional oxygen electrode at high potential.

  7. Electrolytes: Oral Electrolyte Solutions.

    PubMed

    Harris, Lisa

    2017-08-01

    Oral electrolyte solutions are used widely for rehydration in diarrheal illness and to maintain hydration during vigorous exercise. In diarrheal illness, an oral rehydration solution (ORS) typically is preferred over intravenous fluids except for patients with severe dehydration. The preferred ORS is one similar to the glucose-containing reduced osmolarity World Health Organization ORS. There also are polymer-based solutions that use rice or wheat as the source of carbohydrates but these are not widely recommended. Use of other liquids, such as sport drinks, juice, soft drinks, and chicken broth is not recommended, though these can be considered for patients with no or mild dehydration. For maintaining hydration during exercise, particularly vigorous high-intensity exercise, recommendations are to consume fluids (ie, 5 to 7 mL/kg) and a sodium-containing snack at least 4 hours before. During exercise, individuals require 200 to 800 mL/hour of liquid that should contain 20 to 30 mEq/L of sodium. Carbohydrate intake is recommended during high-intensity exercise. Intake of excessive sodium-free fluids should be avoided to prevent exercise-induced hyponatremia. Additional fluids (ie, 1.5 L/kg of weight lost) can be consumed after exercise to restore hydration. Vitamin and mineral supplements are not recommended routinely for athletes unless known deficiencies exist. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  8. Regenerative fuel cell study

    NASA Technical Reports Server (NTRS)

    Wynveen, R. A.; Schubert, F. H.

    1972-01-01

    The completion of the study is reported for the regenerative fuel cell subsystem (RFCS) as an energy storage process for use aboard the space shuttle launched modular space station (MSS). The MSS mission requirements, and RFCS are discussed, and a comparison between RFCS and a nickel cadmium battery subsystem is presented. Development costs are also discussed.

  9. Experimental investigation on combustion of hydrogen-oxygen and methane-oxygen mixtures in the medium of low-superheated steam

    NASA Astrophysics Data System (ADS)

    Pribaturin, N. A.; Fedorov, V. A.; Alekseev, M. V.; Bogomolov, A. R.; Sorokin, A. L.; Azikhanov, S. S.; Shevyrev, S. A.

    2016-05-01

    Experimental data are represented on the investigation of combustion of hydrogen-oxygen and methane-oxygen mixtures in the medium of low-superheated (initial temperature of approximately 150°C) steam at atmospheric pressure. The influence of the ratio of mass flows of the combustible mixture and steam on the qualitative composition of combustion products and the temperature of produced steam is revealed. Main laws for combustion of the hydrogen-oxygen mixture within the steam flow, which affect the completeness of mixture combustion, are determined. Experimental data on the influence of concentrations of the hydrogen-oxygen mixture within the flow of the steam and the combustible mixture upon the completeness of combustion are given. It is found that, when burning the hydrogen-oxygen mixture within the steam flow with a temperature of 1000-1200°C, it is possible using a variation of the combustible mixture flow. At the same time, the volume fraction of noncondensable gases in the produced steam is no more than 2%. It is revealed that there are several combustion modes of the hydrogen-oxygen mixture within the steam flow, in which, in one case, the steam always suppresses combustion and, in another one, detonation of the combustible mixture combustible mixture occurs. It is found that with the excess air factor close to unit, the combustion of the methane-oxygen mixture within steam and the vapor conversion of methane, which result in the appearance of free hydrogen in the produced high-temperature steam, are possible. The description and the principle of the operation of the experimental bench for investigation of combustion of methane-oxygen and hydrogen-oxygen mixtures in the medium of steam are given. Results of experimental investigations of burning fuel and oxygen in the medium of steam are used in the development of a steam superheater for a hightemperature steam turbine.

  10. A Possible Regenerative, Molten-Salt, Thermoelectric Fuel Cell

    NASA Technical Reports Server (NTRS)

    Greenberg, Jacob; Thaller, Lawrence H.; Weber, Donald E.

    1964-01-01

    Molten or fused salts have been evaluated as possible thermoelectric materials because of the relatively good values of their figures of merit, their chemical stability, their long liquid range, and their ability to operate in conjunction with a nuclear reactor to produce heat. In general, molten salts are electrolytic conductors; therefore, there will be a transport of materials and subsequent decomposition with the passage of an electric current. It is possible nonetheless to overcome this disadvantage by using the decomposition products of the molten-salt electrolyte in a fuel cell. The combination of a thermoelectric converter and a fuel cell would lead to a regenerative system that may be useful.

  11. Investigation of electroforming techniques. [fabrication of regeneratively cooled thrust chambers

    NASA Technical Reports Server (NTRS)

    Malone, G. A.

    1975-01-01

    Copper and nickel electroforming was examined for the purpose of establishing the necessary processes and procedures for repeatable, successful fabrication of the outer structures of regeneratively cooled thrust chambers. The selection of electrolytes for copper and nickel deposition is described. The development studies performed to refine and complete the processes necessary for successful chamber shell fabrication and the testing employed to verify the applicability of the processes and procedures to small scale hardware are described. Specifications were developed to afford a guideline for the electroforming of high quality outer shells on regeneratively cooled thrust chamber liners. Test results indicated repeatable mechanical properties could be produced in copper deposits from the copper sulfate electrolyte with periodic current reversal and in nickel deposits from the sulfamate solution. Use of inert, removable channel fillers and the conductivizing of such is described. Techniques (verified by test) which produce high integrity bonds to copper and copper alloy liners are discussed.

  12. Hydrogen-oxygen catalytic ignition and thruster investigation. Volume 1: Catalytic ignition and low pressure thruster evaluations

    NASA Technical Reports Server (NTRS)

    Johnson, R. J.

    1972-01-01

    An experimental and analytical program was conducted to evaluate catalytic igniter operational limits, igniter scaling criteria, and delivered performance of cooled, flightweight gaseous hydrogen-oxygen reaction control thrusters. Specific goals were to: (1) establish operating life and environmental effects for both Shell 405-ABSG and Engelhard MFSA catalysts, (2) provide generalized igniter design guidelines for high response without flashback, and (3) to determine overall performance of thrusters at chamber pressures of 15 and 300 psia (103 and 2068 kN/sq m) and thrust levels of 30 and 1500 lbf, respectively. The experimental results have demonstrated the feasibility of reliable, high response catalytic ignition and the effectiveness of ducted chamber cooling for a high performance flightweight thruster. This volume presents the results of the catalytic igniter and low pressure thruster evaluations are presented.

  13. Performance Comparison of Axisymmetric and Three-dimensional Hydrogen Film Coolant Injection in a 110N Hydrogen/oxygen Rocket

    NASA Technical Reports Server (NTRS)

    Arrington, Lynn A.; Reed, Brian D.

    1992-01-01

    An experimental performance comparison of two geometrically different fuel film coolant injection sleeves was conducted on a 110 N gaseous hydrogen/oxygen rocket. One sleeve had slots milled axially down the walls and the other had a smooth surface to give axisymmetric flow. The comparison was made to investigate a conclusion in an earlier study that attributed a performance underprediction to a symplifying modeling assumption of axisymmetric fuel film flow. The smooth sleeve had higher overall performance at one film coolant percentage and approximately the same or slightly better at another. The study showed that the lack of modeling of three-dimensional effects was not the cause of the performance underprediction as speculated in earlier analytical studies.

  14. Regenerative periodontal therapy.

    PubMed

    Hägi, Tobias T; Laugisch, Oliver; Ivanovic, Aleksandar; Sculean, Anton

    2014-03-01

    The goal of regenerative periodontal therapy is to completely restore the tooth's supporting apparatus that has been lost due to inflammatory periodontal disease or injury. It is characterized by formation of new cementum with inserting collagen fibers, new periodontal ligament, and new alveolar bone. Indeed conventional, nonsurgical, and surgical periodontal therapy usually result in clinical improvements evidenced by probing depth reduction and clinical attachment gain, but the healing occurs predominantly through formation of a long junctional epithelium and no or only unpredictable periodontal regeneration. Therefore, there is an ongoing search for new materials and improved surgical techniques, with the aim of predictably promoting periodontal wound healing/regeneration and improving the clinical outcome. This article attempts to provide the clinician with an overview of the most important biologic events involved in periodontal wound healing/ regeneration and on the criteria on how to select the appropriate regenerative material and surgical technique in order to optimize the clinical outcomes.

  15. Regenerative photonic therapy: Review

    NASA Astrophysics Data System (ADS)

    Salansky, Natasha; Salansky, Norman

    2012-09-01

    After four decades of research of photobiomodulation phenomena in mammals in vitro and in vivo, a solid foundation is created for the use of photobiomodulation in regenerative medicine. Significant accomplishments are achieved in animal models that demonstrate opportunities for photo-regeneration of injured or pathological tissues: skin, muscles and nerves. However, the use of photobiomodulation in clinical studies leads to controversial results while negative or marginal clinical efficacy is reported along with positive findings. A thor ough analysis of requirements to the optical parameters (dosimetry) for high efficacy in photobimodulation led us to the conclusion that there are several misconceptions in the clinical applications of low level laser therapy (LLLT). We present a novel appr oach of regenerative photonic therapy (RPT) for tissue healing and regeneration that overcomes major drawbacks of LLLT. Encouraging clinical results on RPT efficacy are presented. Requirements for RPT approach and vision for its future development for tissue regeneration is discussed.

  16. Regenerative Endodontics: Burning Questions.

    PubMed

    Smith, Anthony J; Cooper, Paul R

    2017-09-01

    Pulp regeneration and its clinical translation into regenerative endodontic procedures are receiving increasing research attention, leading to significant growth of the published scientific and clinical literature within these areas. Development of research strategies, which consider patient-, clinician-, and scientist-based outcomes, will allow greater focus on key research questions driving more rapid clinical translation. Three key areas of focus for these research questions should include cells, signaling, and infection/inflammation. A translational pathway is envisaged in which clinical approaches are increasingly refined to provide regenerative endodontic protocols that are based on a robust understanding of the physiological processes and events responsible for the normal secretion, structure, and biological behavior of pulpal tissue. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. Regenerative feedback resonant circuit

    DOEpatents

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  18. Cytomics in regenerative medicine

    NASA Astrophysics Data System (ADS)

    Tárnok, Attila; Pierzchalski, Arkadiusz

    2008-02-01

    Cytomics is the high-content analysis of cell-systems [6, 78]. The area of Cytomics and Systems Biology received great attention during the last years as it harbours the promise to substantially impact on various fields of biomedicine, drug discovery, predictive medicine [6] and may have major potential for regenerative medicine. In regenerative medicine Cytomics includes process control of cell preparation and culturing using non-invasive detection techniques, quality control and standardization for GMP and GLP conformity and even prediction of cell fate based on sophisticated data analysis. Cytomics requires quantitative and stoichiometric single cell analysis. In some areas the leading cytometric techniques represent the cutting edge today. Many different applications/variations of multicolour staining were developed for flow- or slide-based cytometry (SBC) analysis of suspensions and sections to whole animal analysis [78]. SBC has become an important analytical technology in drug discovery, diagnosis and research and is an emerging technology for systems analysis [78]. It enables high-content high-throughput measurement of cell suspensions, cell cultures and tissues. In the last years various commercial SBC instruments were launched principally enabling to perform similar tasks. Standardisation as well as comparability of different instruments is a major challenge. Hyperspectral optical imaging may be implemented in SBC analysis for label free cell detection based on cellular autofluorescence [3]. All of these developments push the systemic approach of the analysis of biological specimens to enhance the outcome of regenerative medicine.

  19. Liquid electrolytes

    SciTech Connect

    Nagai, J.; Mizuhashi, M.; Kamimori, T.

    1990-12-31

    In contrast to lithium batteries, the electrochromic windows are used under the sunlight, which requires the stability against UV-light, in addition to the usual electrochemical and thermal stabilities. Thus, the selection of the electrode materials and the combination with the electrolytes should be carefully performed in terms of stability requirements. Recently many reports in relation to those subjects were published. Therefore only fundamental properties of liquid electrolytes required for the electrochromic research are reviewed in this chapter.

  20. A 100-W class regenerative fuel cell system for lunar and planetary missions

    NASA Astrophysics Data System (ADS)

    Sone, Yoshitsugu

    The Japan Aerospace Exploration Agency (JAXA) is developing polymer electrolyte fuel cell (PEFC) systems that can be operated under isolated low-gravity and closed environments. In the present study, we combine the PEFC with an electrolyzer in order to realize a regenerative fuel cell. Ideally, if a single cell can be operated as a fuel cell and the cell can be made reversible through the electrolysis reaction, then compact, lightweight regenerative fuel cell systems can be realized. A unitized regenerative fuel cell was prepared, and its operability was demonstrated. During 100-W class operations, a stable fuel cell and electrolysis reaction was observed.

  1. Engineering model system study for a regenerative fuel cell: Study report

    NASA Technical Reports Server (NTRS)

    Chang, B. J.; Schubert, F. H.; Kovach, A. J.; Wynveen, R. A.

    1984-01-01

    Key design issues of the regenerative fuel cell system concept were studied and a design definition of an alkaline electrolyte based engineering model system or low Earth orbit missions was completed. Definition of key design issues for a regenerative fuel cell system include gaseous reactant storage, shared heat exchangers and high pressure pumps. A power flow diagram for the 75 kW initial space station and the impact of different regenerative fuel cell modular sizes on the total 5 year to orbit weight and volume are determined. System characteristics, an isometric drawing, component sizes and mass and energy balances are determined for the 10 kW engineering model system. An open loop regenerative fuel cell concept is considered for integration of the energy storage system with the life support system of the space station. Technical problems and their solutions, pacing technologies and required developments and demonstrations for the regenerative fuel cell system are defined.

  2. Engineering model system study for a regenerative fuel cell: study report

    SciTech Connect

    Chang, B.J.; Schubert, F.H.; Kovach, A.J.; Wynveen, R.A.

    1984-09-01

    Key design issues of the regenerative fuel cell system concept were studied and a design definition of an alkaline electrolyte based engineering model system or low Earth orbit missions was completed. Definition of key design issues for a regenerative fuel cell system include gaseous reactant storage, shared heat exchangers and high pressure pumps. A power flow diagram for the 75 kW initial space station and the impact of different regenerative fuel cell modular sizes on the total 5 year to orbit weight and volume are determined. System characteristics, an isometric drawing, component sizes and mass and energy balances are determined for the 10 kW engineering model system. An open loop regenerative fuel cell concept is considered for integration of the energy storage system with the life support system of the space station. Technical problems and their solutions, pacing technologies and required developments and demonstrations for the regenerative fuel cell system are defined.

  3. Engineering model system study for a regenerative fuel cell: Study report

    NASA Astrophysics Data System (ADS)

    Chang, B. J.; Schubert, F. H.; Kovach, A. J.; Wynveen, R. A.

    1984-09-01

    Key design issues of the regenerative fuel cell system concept were studied and a design definition of an alkaline electrolyte based engineering model system or low Earth orbit missions was completed. Definition of key design issues for a regenerative fuel cell system include gaseous reactant storage, shared heat exchangers and high pressure pumps. A power flow diagram for the 75 kW initial space station and the impact of different regenerative fuel cell modular sizes on the total 5 year to orbit weight and volume are determined. System characteristics, an isometric drawing, component sizes and mass and energy balances are determined for the 10 kW engineering model system. An open loop regenerative fuel cell concept is considered for integration of the energy storage system with the life support system of the space station. Technical problems and their solutions, pacing technologies and required developments and demonstrations for the regenerative fuel cell system are defined.

  4. Regenerative air heater

    DOEpatents

    Hasselquist, P.B.; Baldner, R.

    1980-11-26

    A gas-cooled steel skirt is used to support a refractory cored brick matrix and dome structure in a high temperature regenerative air heater useful in magnetohydrodynamic power generation. The steel skirt thermally expands to accommodate the thermal expansion of the dome structure despite substantial temperature differential thereby reducing relative movement between the dome bricks. Gas cooling of the steel skirt allows the structure to operate above its normal temperature during clean-out cycles and also allows for the control of the thermal expansion of the steel skirt.

  5. Regenerative air heater

    DOEpatents

    Hasselquist, Paul B.; Baldner, Richard

    1982-01-01

    A gas-cooled steel skirt is used to support a refractory cored brick matrix and dome structure in a high temperature regenerative air heater useful in magnetohydrodynamic power generation. The steel skirt thermally expands to accommodate the thermal expansion of the dome structure despite substantial temperature differential thereby reducing relative movement between the dome bricks. Gas cooling of the steel skirt allows the structure to operate above its normal temperature during clean-out cycles and also allows for the control of the thermal expansion of the steel skirt.

  6. REGENERATIVE TRANSISTOR AMPLIFIER

    DOEpatents

    Kabell, L.J.

    1958-11-25

    Electrical circults for use in computers and the like are described. particularly a regenerative bistable transistor amplifler which is iurned on by a clock signal when an information signal permits and is turned off by the clock signal. The amplifier porforms the above function with reduced power requirements for the clock signal and circuit operation. The power requirements are reduced in one way by employing transformer coupling which increases the collector circuit efficiency by eliminating the loss of power in the collector load resistor.

  7. Regenerative Sorption Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Wen, Liang-Chi; Bard, Steven

    1991-01-01

    Two-stage sorption refrigerator achieves increased efficiency via regenerative-heating concept in which waste heat from praseodymium/cerium oxide (PCO) chemisorption compressor runs charcoal/krypton (C/Kr) sorption compressor. Waste heat from each PCO sorption compressor used to power surrounding C/Kr sorption compressor. Flows of heat in two compressor modules controlled by gas-gap thermal switches. Has no wearing moving parts other than extremely long life, room-temperature check valves operating about twice per hour. Virtually no measurable vibration, and has potential operating life of at least ten years.

  8. Regenerative adsorbent heat pump

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative adsorbent heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system and at least a portion of the heat of adsorption. A series of at least four compressors containing an adsorbent is provided. A large amount of heat is transferred from compressor to compressor so that heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  9. Regenerative Medicine Build-Out

    PubMed Central

    Pfenning, Michael A.; Gores, Gregory J.; Harper, C. Michel

    2015-01-01

    Summary Regenerative technologies strive to boost innate repair processes and restitute normative impact. Deployment of regenerative principles into practice is poised to usher in a new era in health care, driving radical innovation in patient management to address the needs of an aging population challenged by escalating chronic diseases. There is urgency to design, execute, and validate viable paradigms for translating and implementing the science of regenerative medicine into tangible health benefits that provide value to stakeholders. A regenerative medicine model of care would entail scalable production and standardized application of clinical grade biotherapies supported by comprehensive supply chain capabilities that integrate sourcing and manufacturing with care delivery. Mayo Clinic has rolled out a blueprint for discovery, translation, and application of regenerative medicine therapies for accelerated adoption into the standard of care. To establish regenerative medical and surgical service lines, the Mayo Clinic model incorporates patient access, enabling platforms and delivery. Access is coordinated through a designated portal, the Regenerative Medicine Consult Service, serving to facilitate patient/provider education, procurement of biomaterials, referral to specialty services, and/or regenerative interventions, often in clinical trials. Platforms include the Regenerative Medicine Biotrust and Good Manufacturing Practice facilities for manufacture of clinical grade products for cell-based, acellular, and/or biomaterial applications. Care delivery leverages dedicated interventional suites for provision of regenerative services. Performance is tracked using a scorecard system to inform decision making. The Mayo Clinic roadmap exemplifies an integrated organization in the discovery, development, and delivery of regenerative medicine within a growing community of practice at the core of modern health care. Significance Regenerative medicine is at the

  10. Regenerative Medicine Build-Out.

    PubMed

    Terzic, Andre; Pfenning, Michael A; Gores, Gregory J; Harper, C Michel

    2015-12-01

    Regenerative technologies strive to boost innate repair processes and restitute normative impact. Deployment of regenerative principles into practice is poised to usher in a new era in health care, driving radical innovation in patient management to address the needs of an aging population challenged by escalating chronic diseases. There is urgency to design, execute, and validate viable paradigms for translating and implementing the science of regenerative medicine into tangible health benefits that provide value to stakeholders. A regenerative medicine model of care would entail scalable production and standardized application of clinical grade biotherapies supported by comprehensive supply chain capabilities that integrate sourcing and manufacturing with care delivery. Mayo Clinic has rolled out a blueprint for discovery, translation, and application of regenerative medicine therapies for accelerated adoption into the standard of care. To establish regenerative medical and surgical service lines, the Mayo Clinic model incorporates patient access, enabling platforms and delivery. Access is coordinated through a designated portal, the Regenerative Medicine Consult Service, serving to facilitate patient/provider education, procurement of biomaterials, referral to specialty services, and/or regenerative interventions, often in clinical trials. Platforms include the Regenerative Medicine Biotrust and Good Manufacturing Practice facilities for manufacture of clinical grade products for cell-based, acellular, and/or biomaterial applications. Care delivery leverages dedicated interventional suites for provision of regenerative services. Performance is tracked using a scorecard system to inform decision making. The Mayo Clinic roadmap exemplifies an integrated organization in the discovery, development, and delivery of regenerative medicine within a growing community of practice at the core of modern health care. Regenerative medicine is at the vanguard of health care

  11. Analysis of regenerative fuel cells

    NASA Technical Reports Server (NTRS)

    Gross, S.

    1982-01-01

    The concept of a rechargeable fuel cell (RFC) system is considered. A newer type of rechargeable battery, the nickel hydrogen (Ni-H2) battery, is also evaluated. A review was made of past studies which showed large variations in weight, cost, and efficiency. Hydrogen-bromine and hydrogen-chlorine regenerable fuel cells were studied, and were found to have a potential for higher energy storage efficiency then the hydrogen-oxygen system. A reduction of up to 15 percent in solar array size may be possible as a result. These systems are not yet developed, but further study of them is recommended.

  12. Regenerative fuel cell systems for mid- to high-orbit satellites

    NASA Technical Reports Server (NTRS)

    Taenaka, R. K.; Adler, E.; Stofel, E. J.; Clark, K. B.

    1987-01-01

    An assessment of the present and projected capabilities of selected hydrogen-oxygen and hydrogen-halogen fuel cell and electrolyzer combinations for energy storage systems (ESS) in configurations useful for spacecraft missions operating in the 10- to 50-kW range for many years in midaltitude to geosynchronous orbits has recently been completed. Results of the study indicate that regenerative fuel cell ESS are feasible for the intended application. A computer model was used to provide tradeoff analyses for optimizing the various ESS fuel cell concepts. When appropriately configured to be compatible with the mission needs of the selected model spacecraft, the specific energy for these ESS are intermediate between that presently available for nickel-hydrogen batteries and that expected for the newly emerging sodium-sulfur technology.

  13. Hazards Induced by Breach of Liquid Rocket Fuel Tanks: Conditions and Risks of Cryogenic Liquid Hydrogen-Oxygen Mixture Explosions

    NASA Technical Reports Server (NTRS)

    Osipov, Viatcheslav; Muratov, Cyrill; Hafiychuk, Halyna; Ponizovskya-Devine, Ekaterina; Smelyanskiy, Vadim; Mathias, Donovan; Lawrence, Scott; Werkheiser, Mary

    2011-01-01

    We analyze the data of purposeful rupture experiments with LOx and LH2 tanks, the Hydrogen-Oxygen Vertical Impact (HOVI) tests that were performed to clarify the ignition mechanisms, the explosive power of cryogenic H2/Ox mixtures under different conditions, and to elucidate the puzzling source of the initial formation of flames near the intertank section during the Challenger disaster. We carry out a physics-based analysis of general explosions scenarios for cryogenic gaseous H2/Ox mixtures and determine their realizability conditions, using the well-established simplified models from the detonation and deflagration theory. We study the features of aerosol H2/Ox mixture combustion and show, in particular, that aerosols intensify the deflagration flames and can induce detonation for any ignition mechanism. We propose a cavitation-induced mechanism of self-ignition of cryogenic H2/Ox mixtures that may be realized when gaseous H2 and Ox flows are mixed with a liquid Ox turbulent stream, as occurred in all HOVI tests. We present an overview of the HOVI tests to make conclusion on the risk of strong explosions in possible liquid rocket incidents and provide a semi-quantitative interpretation of the HOVI data based on aerosol combustion. We uncover the most dangerous situations and discuss the foreseeable risks which can arise in space missions and lead to tragic outcomes. Our analysis relates to only unconfined mixtures that are likely to arise as a result of liquid propellant space vehicle incidents.

  14. Visualization of deflagration-to-detonation transitions in a channel with repeated obstacles using a hydrogen-oxygen mixture

    NASA Astrophysics Data System (ADS)

    Maeda, S.; Minami, S.; Okamoto, D.; Obara, T.

    2016-09-01

    The deflagration-to-detonation transition in a 100 mm square cross-section channel was investigated for a highly reactive stoichiometric hydrogen oxygen mixture at 70 kPa. Obstacles of 5 mm width and 5, 10, and 15 mm heights were equally spaced 60 mm apart at the bottom of the channel. The phenomenon was investigated primarily by time-resolved schlieren visualization from two orthogonal directions using a high-speed video camera. The detonation transition occurred over a remarkably short distance within only three or four repeated obstacles. The global flame speed just before the detonation transition was well below the sound speed of the combustion products and did not reach the sound speed of the initial unreacted gas for tests with an obstacle height of 5 and 10 mm. These results indicate that a detonation transition does not always require global flame acceleration beyond the speed of sound for highly reactive combustible mixtures. A possible mechanism for this detonation initiation was the mixing of the unreacted and reacted gas in the vicinity of the flame front convoluted by the vortex present behind each obstacle, and the formation of a hot spot by the shock wave. The final onset of the detonation originated from the unreacted gas pocket, which was surrounded by the obstacle downstream face and the channel wall.

  15. Reliability and effective thermal conductivity of three metallic-ceramic composite insulating coatings on cooled hydrogen-oxygen rockets

    NASA Technical Reports Server (NTRS)

    Price, H. G., Jr.; Schacht, R. L.; Quentmeyer, R. J.

    1973-01-01

    An experimental investigation of the structural integrity and effective thermal conductivity of three metallic-ceramic composite coatings was conducted. These coatings were plasma sprayed onto the combustion side of water-cooled, 12.7-centimeter throat diameter, hydrogen-oxygen rocket thrust chambers operating at 2.07 to 4.14 meganewtons per square meter chamber pressure. The metallic-ceramic composites functioned for six to 17 cycles and for as long as 213 seconds of rocket operations and could have probably provided their insulating properties for many additional cycles. The effective thermal conductivity of all the coatings was in the range of 0.7472 to 4.483 w/(m)(K), which makes the coatings a very effective thermal barrier. Photomicrographic studies of cross-sectioned coolant tubes seem to indicate that the effective thermal conductivity of the coatings is controlled by contact resistance between the particles, as a result of the spraying process, and not the thermal conductivity of the bulk materials.

  16. Will Regenerative Medicine Replace Transplantation?

    PubMed Central

    Orlando, Giuseppe; Soker, Shay; Stratta, Robert J.; Atala, Anthony

    2013-01-01

    Recent groundbreaking advances in organ bioengineering and regeneration have provided evidence that regenerative medicine holds promise to dramatically improve the approach to organ transplantation. The two fields, however, share a common heritage. Alexis Carrel can be considered the father of both regenerative medicine and organ transplantation, and it is now clear that his legacy is equally applicable for the present and future generations of transplant and regenerative medicine investigators. In this review, we will briefly illustrate the interplay that should be established between these two complementary disciplines of health sciences. Although regenerative medicine has shown to the transplant field its potential, transplantation is destined to align with regenerative medicine and foster further progress probably more than either discipline alone. Organ bioengineering and regeneration technologies hold the promise to meet at the same time the two most urgent needs in organ transplantation, namely, the identification of a new, potentially inexhaustible source of organs and immunosuppression-free transplantation of tissues and organs. PMID:23906883

  17. Active Magnetic Regenerative Liquefier

    SciTech Connect

    Barclay, John A.; Oseen-Send, Kathryn; Ferguson, Luke; Pouresfandiary, Jamshid; Cousins, Anand; Ralph, Heather; Hampto, Tom

    2016-01-12

    This final report for the DOE Project entitled Active Magnetic Regenerative Liquefier (AMRL) funded under Grant DE-FG36-08GO18064 to Heracles Energy Corporation d.b.a. Prometheus Energy (Heracles/Prometheus) describes an active magnetic regenerative refrigerator (AMRR) prototype designed and built during the period from July 2008 through May 2011. The primary goal of this project was to make significant technical advances toward highly efficient liquefaction of hydrogen. Conventional hydrogen liquefiers at any scale have a maximum FOM of ~0.35 due primarily to the intrinsic difficulty of rapid, efficient compression of either hydrogen or helium working gases. Numerical simulation modeling of high performance AMRL designs indicates certain designs have promise to increase thermodynamic efficiency from a FOM of ~0.35 toward ~0.5 to ~0.6. The technical approach was the use of solid magnetic working refrigerants cycled in and out of high magnetic fields to build an efficient active regenerative magnetic refrigeration module providing cooling power for AMRL. A single-stage reciprocating AMRR with a design temperature span from ~290 K to ~120 K was built and tested with dual magnetic regenerators moving in and out of the conductively-cooled superconducting magnet subsystem. The heat transfer fluid (helium) was coupled to the process stream (refrigeration/liquefaction load) via high performance heat exchangers. In order to maximize AMRR efficiency a helium bypass loop with adjustable flow was incorporated in the design because the thermal mass of magnetic refrigerants is higher in low magnetic field than in high magnetic field. Heracles/Prometheus designed experiments to measure AMRR performance under a variety of different operational parameters such as cycle frequency, magnetic field strength, heat transfer fluid flow rate, amount of bypass flow of the heat transfer fluid while measuring work input, temperature span, cooling capability as a function of cold temperature

  18. Electrolyte Racers

    ERIC Educational Resources Information Center

    Kellie, Shawn; Kellie, Tonya; Corbin-Tipton, Elizabeth

    2006-01-01

    A fast way to teach investigative skills in science is to tie them to NASCAR using Hot Wheels Formula Fuelers Race Cars. These inexpensive toy cars travel different distances based on the strength of the "electrolyte" (a substance that conducts electricity when dissolved in water) in their "fuel" tanks. Advertisements for these race cars urge kids…

  19. Electrolyte Racers

    ERIC Educational Resources Information Center

    Kellie, Shawn; Kellie, Tonya; Corbin-Tipton, Elizabeth

    2006-01-01

    A fast way to teach investigative skills in science is to tie them to NASCAR using Hot Wheels Formula Fuelers Race Cars. These inexpensive toy cars travel different distances based on the strength of the "electrolyte" (a substance that conducts electricity when dissolved in water) in their "fuel" tanks. Advertisements for these race cars urge kids…

  20. Regenerative periodontal therapy.

    PubMed

    Kao, Daniel W K; Fiorellini, Joseph P

    2012-01-01

    Traditional treatment for loss of bone and attachment due to periodontal disease has focused around repairing the damage induced. However, over the past few decades, clinicians have begun to utilize regenerative techniques to rebuild bone, cementum and the periodontal ligament. Conventional procedures most often involve the use of barrier membranes with bone grafts that foster selective cell repopulation and regrowth of osseous structures. Since the predictability of these techniques may be limited to certain case types, pharmacologically based efforts are underway to investigate the possibility of harnessing osseous regrowth potential. Clinical research has found that proteins are potent biological mediators that promote many of the events in wound healing, and have been shown to promote bone formation in human clinical studies.

  1. PEM regenerative fuel cells

    NASA Technical Reports Server (NTRS)

    Swette, Larry L.; Laconti, Anthony B.; Mccatty, Stephen A.

    1993-01-01

    This paper will update the progress in developing electrocatalyst systems and electrode structures primarily for the positive electrode of single-unit solid polymer proton exchange membrane (PEM) regenerative fuel cells. The work was done with DuPont Nafion 117 in complete fuel cells (40 sq cm electrodes). The cells were operated alternately in fuel cell mode and electrolysis mode at 80 C. In fuel cell mode, humidified hydrogen and oxygen were supplied at 207 kPa (30 psi); in electrolysis mode, water was pumped over the positive electrode and the gases were evolved at ambient pressure. Cycling data will be presented for Pt-Ir catalysts and limited bifunctional data will be presented for Pt, Ir, Ru, Rh, and Na(x)Pt3O4 catalysts as well as for electrode structure variations.

  2. Regenerative braking device

    DOEpatents

    Hoppie, Lyle O.

    1982-01-12

    Disclosed are several embodiments of a regenerative braking device for an automotive vehicle. The device includes a plurality of rubber rollers (24, 26) mounted for rotation between an input shaft (14) connectable to the vehicle drivetrain and an output shaft (16) which is drivingly connected to the input shaft by a variable ratio transmission (20). When the transmission ratio is such that the input shaft rotates faster than the output shaft, the rubber rollers are torsionally stressed to accumulate energy, thereby slowing the vehicle. When the transmission ratio is such that the output shaft rotates faster than the input shaft, the rubber rollers are torsionally relaxed to deliver accumulated energy, thereby accelerating or driving the vehicle.

  3. Hydrogels in Regenerative Medicine

    PubMed Central

    Slaughter, Brandon V.; Khurshid, Shahana S.; Fisher, Omar Z.; Khademhosseini, Ali

    2015-01-01

    Hydrogels, due to their unique biocompatibility, flexible methods of synthesis, range of constituents, and desirable physical characteristics, have been the material of choice for many applications in regenerative medicine. They can serve as scaffolds that provide structural integrity to tissue constructs, control drug and protein delivery to tissues and cultures, and serve as adhesives or barriers between tissue and material surfaces. In this work, the properties of hydrogels that are important for tissue engineering applications and the inherent material design constraints and challenges are discussed. Recent research involving several different hydrogels polymerized from a variety of synthetic and natural monomers using typical and novel synthetic methods are highlighted. Finally, special attention is given to the microfabrication techniques that are currently resulting in important advances in the field. PMID:20882499

  4. Regenerative combustion device

    DOEpatents

    West, Phillip B.

    2004-03-16

    A regenerative combustion device having a combustion zone, and chemicals contained within the combustion zone, such as water, having a first equilibrium state, and a second combustible state. Means for transforming the chemicals from the first equilibrium state to the second combustible state, such as electrodes, are disposed within the chemicals. An igniter, such as a spark plug or similar device, is disposed within the combustion zone for igniting combustion of the chemicals in the second combustible state. The combustion products are contained within the combustion zone, and the chemicals are selected such that the combustion products naturally chemically revert into the chemicals in the first equilibrium state following combustion. The combustion device may thus be repeatedly reused, requiring only a brief wait after each ignition to allow the regeneration of combustible gasses within the head space.

  5. A hydrogen-oxygen rocket engine coolant passage design program (RECOP) for fluid-cooled thrust chambers and nozzles

    NASA Technical Reports Server (NTRS)

    Tomsik, Thomas M.

    1994-01-01

    The design of coolant passages in regeneratively cooled thrust chambers is critical to the operation and safety of a rocket engine system. Designing a coolant passage is a complex thermal and hydraulic problem requiring an accurate understanding of the heat transfer between the combustion gas and the coolant. Every major rocket engine company has invested in the development of thrust chamber computer design and analysis tools; two examples are Rocketdyne's REGEN code and Aerojet's ELES program. In an effort to augment current design capabilities for government and industry, the NASA Lewis Research Center is developing a computer model to design coolant passages for advanced regeneratively cooled thrust chambers. The RECOP code incorporates state-of-the-art correlations, numerical techniques and design methods, certainly minimum requirements for generating optimum designs of future space chemical engines. A preliminary version of the RECOP model was recently completed and code validation work is in progress. This paper introduces major features of RECOP and compares the analysis to design points for the first test case engine; the Pratt & Whitney RL10A-3-3A thrust chamber.

  6. The pharmacology of regenerative medicine.

    PubMed

    Christ, George J; Saul, Justin M; Furth, Mark E; Andersson, Karl-Erik

    2013-07-01

    Regenerative medicine is a rapidly evolving multidisciplinary, translational research enterprise whose explicit purpose is to advance technologies for the repair and replacement of damaged cells, tissues, and organs. Scientific progress in the field has been steady and expectations for its robust clinical application continue to rise. The major thesis of this review is that the pharmacological sciences will contribute critically to the accelerated translational progress and clinical utility of regenerative medicine technologies. In 2007, we coined the phrase "regenerative pharmacology" to describe the enormous possibilities that could occur at the interface between pharmacology, regenerative medicine, and tissue engineering. The operational definition of regenerative pharmacology is "the application of pharmacological sciences to accelerate, optimize, and characterize (either in vitro or in vivo) the development, maturation, and function of bioengineered and regenerating tissues." As such, regenerative pharmacology seeks to cure disease through restoration of tissue/organ function. This strategy is distinct from standard pharmacotherapy, which is often limited to the amelioration of symptoms. Our goal here is to get pharmacologists more involved in this field of research by exposing them to the tools, opportunities, challenges, and interdisciplinary expertise that will be required to ensure awareness and galvanize involvement. To this end, we illustrate ways in which the pharmacological sciences can drive future innovations in regenerative medicine and tissue engineering and thus help to revolutionize the discovery of curative therapeutics. Hopefully, the broad foundational knowledge provided herein will spark sustained conversations among experts in diverse fields of scientific research to the benefit of all.

  7. Solid electrolytes

    DOEpatents

    Abraham, Kuzhikalail M.; Alamgir, Mohamed

    1993-06-15

    This invention pertains to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of solvates of Li salts immobilized (encapsulated) in a solid organic polymer matrix. In particular, this invention relates to solid polymer electrolytes derived by immobilizing complexes (solvates) formed between a Li salt such as LiAsF.sub.6, LiCF.sub.3 SO.sub.3 or LiClO.sub.4 and a mixture of aprotic organic solvents having high dielectric constants such as ethylene carbonate (EC) (dielectric constant=89.6) and propylene carbonate (PC) (dielectric constant=64.4) in a polymer matrix such as polyacrylonitrile, poly(tetraethylene glycol diacrylate), or poly(vinyl pyrrolidinone).

  8. Decellularized scaffolds in regenerative medicine

    PubMed Central

    Yu, Yaling; Alkhawaji, Ali; Ding, Yuqiang; Mei, Jin

    2016-01-01

    Allogeneic organ transplantation remains the ultimate solution for end-stage organ failure. Yet, the clinical application is limited by the shortage of donor organs and the need for lifelong immunosuppression, highlighting the importance of developing effective therapeutic strategies. In the field of regenerative medicine, various regenerative technologies have lately been developed using various biomaterials to address these limitations. Decellularized scaffolds, derived mainly from various non-autologous organs, have been proved a regenerative capability in vivo and in vitro and become an emerging treatment approach. However, this regenerative capability varies between scaffolds as a result of the diversity of anatomical structure and cellular composition of organs used for decellularization. Herein, recent advances in scaffolds based on organ regeneration in vivo and in vitro are highlighted along with aspects where further investigations and analyses are needed. PMID:27486772

  9. Thermally regenerative fuel cells

    NASA Astrophysics Data System (ADS)

    Ludwig, F. A.; Kindler, A.; McHardy, J.

    1991-10-01

    The three phase project was undertaken to investigate solventless ionic liquids as possible working fluids for a new type of thermally regenerative fuel cell (TRFC). The heart of the new device, invented at Hughes Aircraft Company in 1983, is an electrochemical concentration cell where acid and base streams react to produce electrical energy. Thermal energy is then used to decompose the resulting salts and regenerate the cell reactants. In principle, a TRFC can be matched to any source of thermal energy simply by selecting working fluids with the appropriate regeneration temperature. However, aqueous working fluids (the focus of previous studies) impose limitations on both the operating temperatures and the achievable energy densities. It was the need to overcome these limitations that prompted the present investigation. Specific aims were to identify possible working fluids for TRFC systems with both low and high regeneration temperatures. A major advantage of our aqueous-fluid TRFC systems has been the ability to use hydrogen electrodes. The low activation and mass transfer losses of these electrodes contribute substantially to overall system efficiency.

  10. Personalized Regenerative Medicine.

    PubMed

    Arjmand, Babak; Goodarzi, Parisa; Mohamadi-Jahani, Fereshteh; Falahzadeh, Khadijeh; Larijani, Bagher

    2017-03-01

    Personalized medicine as a novel field of medicine refers to the prescription of specific therapeutics procedure for an individual. This approach has established based on pharmacogenetic and pharmacogenomic information and data. The terms precision and personalized medicines are sometimes applied interchangeably. However, there has been a shift from "personalized medicine" towards "precision medicine". Although personalized medicine emerged from pharmacogenetics, nowadays it covers many fields of healthcare. Accordingly, regenerative medicine and cellular therapy as the new fields of medicine use cell-based products in order to develop personalized treatments. Different sources of stem cells including mesenchymal stem cells, embryonic stem cells and induced pluripotent stem cells (iPSCs) have been considered in targeted therapies which could give many advantages. iPSCs as the novel and individual pluripotent stem cells have been introduced as the appropriate candidates for personalized cell therapies. Cellular therapies can provide a personalized approach. Because of person-to-person and population differences in the result of stem cell therapy, individualized cellular therapy must be adjusted according to the patient specific profile, in order to achieve best therapeutic results and outcomes. Several factors should be considered to achieve personalized stem cells therapy such as, recipient factors, donor factors, and the overall body environment in which the stem cells could be active and functional. In addition to these factors, the source of stem cells must be carefully chosen based on functional and physical criteria that lead to optimal outcomes.

  11. Regenerative switching CMOS system

    DOEpatents

    Welch, James D.

    1998-01-01

    Complementary Metal Oxide Semiconductor (CMOS) Schottky barrier Field Effect Transistor systems, which are a seriesed combination of N and P-Channel MOSFETS, in which Source Schottky barrier junctions of the N and P-Channel Schottky barrier MOSFETS are electically interconnected, (rather than the Drains as in conventional diffused junction CMOS), which Schottky barrier MOSFET system demonstrates Regenerative Inverting Switching Characteristics in use are disclosed. Both the N and P-Channel Schottky barrier MOSFET devices are unique in that they provide operational Drain Current vs. Drain to Source voltage as a function of Gate voltage only where the polarities of the Drain voltage and Gate voltage are opposite, referenced to the Source as a common terminal, and where the polarity of the voltage applied to the Gate is appropriate to cause Channel inversion. Experimentally derived results which demonstrate and verify the operation of N and P-Channel Schottky barrier MOSFETS actually fabricated on P and N-type Silicon respectively, by a common procedure using vacuum deposited Chromium as a Schottky barrier forming metal, are also provided.

  12. Regenerative switching CMOS system

    DOEpatents

    Welch, J.D.

    1998-06-02

    Complementary Metal Oxide Semiconductor (CMOS) Schottky barrier Field Effect Transistor systems, which are a series combination of N and P-Channel MOSFETS, in which Source Schottky barrier junctions of the N and P-Channel Schottky barrier MOSFETS are electrically interconnected, (rather than the Drains as in conventional diffused junction CMOS), which Schottky barrier MOSFET system demonstrates Regenerative Inverting Switching Characteristics in use are disclosed. Both the N and P-Channel Schottky barrier MOSFET devices are unique in that they provide operational Drain Current vs. Drain to Source voltage as a function of Gate voltage only where the polarities of the Drain voltage and Gate voltage are opposite, referenced to the Source as a common terminal, and where the polarity of the voltage applied to the Gate is appropriate to cause Channel inversion. Experimentally derived results which demonstrate and verify the operation of N and P-Channel Schottky barrier MOSFETS actually fabricated on P and N-type Silicon respectively, by a common procedure using vacuum deposited Chromium as a Schottky barrier forming metal, are also provided. 14 figs.

  13. Electrolyte salts for nonaqueous electrolytes

    DOEpatents

    Amine, Khalil; Zhang, Zhengcheng; Chen, Zonghai

    2012-10-09

    Metal complex salts may be used in lithium ion batteries. Such metal complex salts not only perform as an electrolyte salt in a lithium ion batteries with high solubility and conductivity, but also can act as redox shuttles that provide overcharge protection of individual cells in a battery pack and/or as electrolyte additives to provide other mechanisms to provide overcharge protection to lithium ion batteries. The metal complex salts have at least one aromatic ring. The aromatic moiety may be reversibly oxidized/reduced at a potential slightly higher than the working potential of the positive electrode in the lithium ion battery. The metal complex salts may also be known as overcharge protection salts.

  14. Solar photochemical production of HBr for off-peak electrolytic hydrogen production

    SciTech Connect

    Heaton, H.

    1996-10-01

    Progress is reported on the development of a unique and innovative hydrogen production concept utilizing renewable (Solar) energy and incorporating energy storage. The concept is based on a solar-electrolytic system for production of hydrogen and oxygen. It employs water, bromine, solar energy, and supplemental electrical power. The process consumes only water, sunlight and off-peak electricity, and produces only hydrogen, oxygen, and peaking electrical power. No pollutants are emitted, and fossil fuels are not consumed. The concept is being developed by Solar Reactor Technologies, Inc., (SRT) under the auspices of a Cooperative Agreement with the U.S. Department of Energy (DOE).

  15. Regenerative fuel cells for space and terrestrial use

    NASA Astrophysics Data System (ADS)

    Tillmetz, Werner; Dietrich, Guenther; Benz, Uwe

    Electrolysis, fuel cell, and energy storage technologies are compared and evaluated. The use of a fuel cell and electrolyzer with an immobilized electrolyte is selected as the most promising technique. A comparison of the batteries demonstrates that a RFCS (regenerative fuel cell system) could be a serious competitor in future space activities, especially with increasing power level and energy to be stored. Also, for many terrestrial applications, highly efficient energy storage systems will be of great interest in the near future. Aspects of the terrestrial use of a RFCS are discussed.

  16. Hybrid regenerative fuel cell systems for space applications

    NASA Technical Reports Server (NTRS)

    Saucier, David R.

    1988-01-01

    This paper describes a hybrid regenerative fuel cell (RFC) system for space application, which is made up of an alkaline fuel cell (Space Shuttle fuel cell) and an acid electrolysis unit (solid polymer electrolyte). In the RFC, gas produced from the acid electrolysis unit and water produced by the alkaline fuel cell are repeatedly reacted in the other unit. The results of RFC's tests indicate that the system is feasible in terms of fluid/unit compatibility. In addition, the fuel cell thermal-control system proved capable of controlling fuel cell temperatures throughout long open-circuit periods. Diagrams of the RFC and its subsystems are included.

  17. Thermodynamic measurements in a high pressure hydrogen-oxygen flame using Raman scattering from a broadband excimer laser

    NASA Technical Reports Server (NTRS)

    Hartfield, Roy, Jr.

    1996-01-01

    Raman scattering is an inelastic molecular scattering process in which incident radiation is reemitted at a fixed change in frequency. Raman spectroscopy can be used to measure the number density and temperature of the irradiated species. The strength of the Raman signal is inversely proportional to the wavelength raised to the fourth power. Consequently, high signal to noise ratios are obtained by using ultraviolet (UV) excitation sources. Using UV sources for Raman Spectroscopy in flames is complicated by the fact that some of the primary constituents in hydrogen-oxygen combustion absorb and reemit light in the UV and these fluorescence processes interfere with the Raman signals. This problem has been handled in atmospheric pressure flames in some instances by using a narrowband tunable excimer laser as a source. This allows for detuning from absorption transitions and the elimination of interfering fluorescence signals at the Raman wavelengths. This approach works well in the atmospheric pressure flame; however, it has two important disadvantages. First, injection-locked narrowband tunable excimer lasers are very expensive. More importantly, however, is the fact that at the high pressures characteristic of rocket engine combustion chambers, the absorption transitions are broadened making it difficult to tune to a spectral location at which substantial absorption would not occur. The approach taken in this work is to separate the Raman signal from the fluorescence background by taking advantage of the fact that Raman signal has nonisotropic polarization characteristics while the fluorescence signals are unpolarized. Specifically, for scattering at right angles to the excitation beam path, the Raman signal is completely polarized. The Raman signal is separated from the fluorescence background by collecting both horizontally and vertically polarized signals separately. One of the polarizations has both the Raman signal and the fluorescence background while the

  18. The Pharmacology of Regenerative Medicine

    PubMed Central

    Saul, Justin M.; Furth, Mark E.; Andersson, Karl-Erik

    2013-01-01

    Regenerative medicine is a rapidly evolving multidisciplinary, translational research enterprise whose explicit purpose is to advance technologies for the repair and replacement of damaged cells, tissues, and organs. Scientific progress in the field has been steady and expectations for its robust clinical application continue to rise. The major thesis of this review is that the pharmacological sciences will contribute critically to the accelerated translational progress and clinical utility of regenerative medicine technologies. In 2007, we coined the phrase “regenerative pharmacology” to describe the enormous possibilities that could occur at the interface between pharmacology, regenerative medicine, and tissue engineering. The operational definition of regenerative pharmacology is “the application of pharmacological sciences to accelerate, optimize, and characterize (either in vitro or in vivo) the development, maturation, and function of bioengineered and regenerating tissues.” As such, regenerative pharmacology seeks to cure disease through restoration of tissue/organ function. This strategy is distinct from standard pharmacotherapy, which is often limited to the amelioration of symptoms. Our goal here is to get pharmacologists more involved in this field of research by exposing them to the tools, opportunities, challenges, and interdisciplinary expertise that will be required to ensure awareness and galvanize involvement. To this end, we illustrate ways in which the pharmacological sciences can drive future innovations in regenerative medicine and tissue engineering and thus help to revolutionize the discovery of curative therapeutics. Hopefully, the broad foundational knowledge provided herein will spark sustained conversations among experts in diverse fields of scientific research to the benefit of all. PMID:23818131

  19. ``HYTEC''—A thermally regenerative fuel cell

    NASA Astrophysics Data System (ADS)

    Roy, Prodyot; Salamah, Samir A.; Maldonado, Jerry; Narkiewicz, Regina S.

    1993-01-01

    HYTEC (Hydrogen Thermo-Electrochemical Converter) is a thermally regenerative fuel cell for direct conversion of heat into electricity. The principles of basic cell operation involve ionic transport of hydrogen through a hydride-ion (H-) conducting, molten electrolyte, and reaction with alkali metals, oxygen, or air. In order to operate HYTEC in a thermally regenerative mode, pure Li and Na, or a mixture of Li/Na alloy, is used for reaction with hydrogen, to form metal hydride which is subsequently decomposed to metal and hydrogen at higher temperatures. The reactants are then separated and redirected to the electrochemical cell. In the cell the molten, H--conducting electrolyte is immobilized between two thin hydrogen-permeable, solid, metallic electrodes which also act as current collectors. The H2 gas first diffuses through the cathode electrode and forms a hydride ion (H+e→H-) at the cathode-electrolyte interface. The H- ion subsequently migrated through the electrolyte under a chemical potential gradient created by the presence of the alkali metal in the anode chamber. The H- ion releases the electron to form hydrogen atoms (H-→H+e) at the anode-electrolyte interface. The hydrogen atom diffuses through the anode electrode and reacts with the alkali metal to form metal hydride. The electron released passes through the load circuit to complete the cycle. In the regeneration scheme, the fuel cell is operated at temperature T1. The metal hydride formed at the anode is pumped to the decomposition chamber through a recuperator. The metal hydride is decomposed at a higher temperature, T2, by an external heat source. The H2 gas is separated from the alkali metal by a H2-permeable, solid, metallic membrane and fed into the anode chamber of the cell. The hydrogen-depleted alkali metal is directed to the cathode chamber of the cell, via the recuperator, to complete the cycle. To date, electrochemical feasibility of the concept has been experimentally demonstrated. A

  20. Regenerative Endodontics for Adult Patients.

    PubMed

    He, Ling; Kim, Sahng G; Gong, Qimei; Zhong, Juan; Wang, Sainan; Zhou, Xuedong; Ye, Ling; Ling, Junqi; Mao, Jeremy J

    2017-09-01

    The goal of endodontics is to save teeth. Since inception, endodontic treatments are performed to obturate disinfected root canals with inert materials such as gutta-percha. Although teeth can be saved after successful endodontic treatments, they are devitalized and therefore susceptible to reinfections and fractures. The American Association of Endodontists (AAE) has made a tremendous effort to revitalize disinfected immature permanent teeth in children and adolescents with diagnoses including pulp necrosis or apical periodontitis. The American Dental Association (ADA) in 2011 issued several clinical codes for regenerative endodontic procedures or apical revascularization in necrotic immature permanent teeth in children and adolescents. These AAE and ADA initiatives have stimulated robust interest in devising a multitude of tissue engineering approaches for dental pulp and dentin regeneration. Can the concept of regenerative endodontics be extended to revitalize mature permanent teeth with diagnoses including irreversible pulpitis and/or pulp necrosis in adults? The present article was written not only to summarize emerging findings to revitalize mature permanent teeth in adult patients but also to identify challenges and strategies that focus on realizing the goal of regenerative endodontics in adults. We further present clinical cases and describe the biological basis of potential regenerative endodontic procedures in adults. This article explores the frequently asked question if regenerative endodontic therapies should be developed for dental pulp and/or dentin regeneration in adults, who consist of the great majority of endodontic patients. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Bio-regenerative life support

    NASA Technical Reports Server (NTRS)

    Macelroy, Robert D.; Wydeven, Theodore, Jr.

    1989-01-01

    The basis for and the potential uses of bio-regenerative life support are examined. Bio-regenerative life support systems are an alternative to physical-chemical regeneration techniques for use when resupply of a crew in space is expensive, or when the logistics of resupply are difficult. Many of the scientific studies required for bio-regenerative life support systems have been completed and preliminary development of some components will begin within the next 12 to 18 months. The focus of the work that lies ahead will be efficient power and mass use, long-term system stability, component function, systems integration, and extensive testing in the space environment. Because of the advantages of bio-regeneration, it is anticipated that human life support for long-term space missions will evolve to include increasingly large amounts of biologically-based regeneration.

  2. Biomaterials for Bone Regenerative Engineering.

    PubMed

    Yu, Xiaohua; Tang, Xiaoyan; Gohil, Shalini V; Laurencin, Cato T

    2015-06-24

    Strategies for bone tissue regeneration have been continuously evolving for the last 25 years since the introduction of the "tissue engineering" concept. The convergence of the life, physical, and engineering sciences has brought in several advanced technologies available to tissue engineers and scientists. This resulted in the creation of a new multidisciplinary field termed as "regenerative engineering". In this article, the role of biomaterials in bone regenerative engineering is systematically reviewed to elucidate the new design criteria for the next generation of biomaterials for bone regenerative engineering. The exemplary design of biomaterials harnessing various materials characteristics towards successful bone defect repair and regeneration is highlighted. Particular attention is given to the attempts of incorporating advanced materials science, stem cell technologies, and developmental biology into biomaterials design to engineer and develop the next generation bone grafts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Relative humidity across the Paleocene-Eocene Thermal Maximum via combined hydrogen-oxygen isotope paleohygrometry (Invited)

    NASA Astrophysics Data System (ADS)

    McInerney, F. A.; Bloch, J. I.; Secord, R.; Wing, S. L.; Kraus, M. J.; Boyer, D. M.

    2009-12-01

    The Paleocene-Eocene Thermal Maximum (PETM) presents an opportunity to characterize continental hydrologic changes during rapid and extreme global warming. The Bighorn Basin, Wyoming, USA, has long been recognized for the PETM sequences preserved there and sits in an ideal location for recording hydrologic changes in the interior of North America. The southeast Bighorn Basin is of particular interest because it contains not only alluvial paleosols and vertebrate fossils, but also macrofloral remains from the PETM. The carbon isotope excursion associated with this event is preserved in this part of the Basin in leaf wax lipids, tooth enamel, and bulk organic matter. To characterize the hydrologic changes that occurred during the PETM we are applying a suite of isotopic, paleobotanical and paleopedological approaches to sections in the southeast Bighorn Basin. Reported here are results from the combined hydrogen and oxygen isotope analysis aimed at reconstructing relative humidity. Oxygen isotope ratios (δ18O) of biogenic apatite from mammalian tooth enamel and fish scales vary with environment, physiology and diet. Because mammals are homeothermic, they primarily track surface water values with predictable physiological offsets. Hydrogen isotope ratios (δD) of leaf-wax lipids (long-chain n-alkanes) reflect both meteoric water δD values and additional D-enrichment caused by evapotranspiration. The enrichment factor between water δD and n-alkane δD can therefore be used as a proxy for relative humidity (RH). In this study, δ18O of surface water is estimated using the δ18O of Coryphodon tooth enamel. We use these δ18O values to estimate surface water δD values using the Global Meteoric Water Line (δD = 8δ18O + 10). We then calculate relative humidity from n-alkane δD values using a Craig-Gordon type isotopic model for D-enrichment caused by transpiration from leaves. Results of the combined hydrogen-oxygen isotope paleohygrometer indicate a general rise in

  4. Regeneratively Cooled Porous Media Jacket

    NASA Technical Reports Server (NTRS)

    Mungas, Greg (Inventor); Fisher, David J. (Inventor); London, Adam Pollok (Inventor); Fryer, Jack Merrill (Inventor)

    2013-01-01

    The fluid and heat transfer theory for regenerative cooling of a rocket combustion chamber with a porous media coolant jacket is presented. This model is used to design a regeneratively cooled rocket or other high temperature engine cooling jacket. Cooling jackets comprising impermeable inner and outer walls, and porous media channels are disclosed. Also disclosed are porous media coolant jackets with additional structures designed to transfer heat directly from the inner wall to the outer wall, and structures designed to direct movement of the coolant fluid from the inner wall to the outer wall. Methods of making such jackets are also disclosed.

  5. Laser system using regenerative amplifier

    DOEpatents

    Emmett, John L. [Pleasanton, CA

    1980-03-04

    High energy laser system using a regenerative amplifier, which relaxes all constraints on laser components other than the intrinsic damage level of matter, so as to enable use of available laser system components. This can be accomplished by use of segmented components, spatial filters, at least one amplifier using solid state or gaseous media, and separated reflector members providing a long round trip time through the regenerative cavity, thereby allowing slower switching and adequate time to clear the spatial filters, etc. The laser system simplifies component requirements and reduces component cost while providing high energy output.

  6. Thermoacoustic simulator for regenerative machines

    NASA Astrophysics Data System (ADS)

    Luo, E.; Wu, J.; Yang, J.; Xiao, J.

    2002-05-01

    Linear thermoacoustic theory is a powerful tool to understand the working mechanism of many regenerative machines. Based on the theory, the authors have developed a computer code "Thermoacoustic Simulator" for analyzing and designing different regenerative cryocoolers including String refrigerators, Stirling and G-M types of pulse tube refrigerators and G-M cryocoolers. Also, standing-wave and traveling-wave thermoacoustic machines can be simulated, too. This paper will present the philosophy of the "Thermoacoustic Simulator" and some demonstrations of simulation for different types of cryocoolers and thermoacoustic engines.

  7. Laser system using regenerative amplifier

    DOEpatents

    Emmett, J.L.

    1980-03-04

    High energy laser system is disclosed using a regenerative amplifier, which relaxes all constraints on laser components other than the intrinsic damage level of matter, so as to enable use of available laser system components. This can be accomplished by use of segmented components, spatial filters, at least one amplifier using solid state or gaseous media, and separated reflector members providing a long round trip time through the regenerative cavity, thereby allowing slower switching and adequate time to clear the spatial filters, etc. The laser system simplifies component requirements and reduces component cost while providing high energy output. 10 figs.

  8. Regenerative Endodontics by Cell Homing.

    PubMed

    He, Ling; Zhong, Juan; Gong, Qimei; Cheng, Bin; Kim, Sahng G; Ling, Junqi; Mao, Jeremy J

    2017-01-01

    Apical revascularization (AR) and platelet-rich plasma have been used to restore dental pulp vitality in infected immature permanent teeth. Two regenerative therapies are cell transplantation and cell homing. This article updates and benchmarks these therapies with cell homing. A case report concluded that AR increased root length; however, quantitative and statistical assessments disproved this. Regenerative endodontic therapies require prospective clinical trials demonstrating safety and efficacy. These therapies are intrinsically susceptible to procedural and patient variations. Cell homing uses novel molecules that drive therapeutic efficacy, and may be less sensitive to procedural and patient variations. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. [Regenerative nodular hyperplasia in HIV].

    PubMed

    González, Ramiro Javier Romo; Chaves, Emiliano; Mullen, Eduardo; Copello, Hercilia

    2011-12-01

    Nodular regenerative hyperplasia of the liver is a rare condition. We describe here the case of a patient with HIV who presented with a clinical syndrome of portal hypertension. After multiple evaluations the diagnosis was recognized by the histology. The findings were attributed to the prolonged use of didanosine.

  10. Nondestructive test of regenerative chambers

    NASA Technical Reports Server (NTRS)

    Malone, G. A.; Stauffis, R.; Wood, R.

    1972-01-01

    Flat panels simulating internally cooled regenerative thrust chamber walls were fabricated by electroforming, brazing and diffusion bonding to evaluate the feasibility of nondestructive evaluation techniques to detect bonds of various strength integrities. Ultrasonics, holography, and acoustic emission were investigated and found to yield useful and informative data regarding the presence of bond defects in these structures.

  11. Regenerative Strategies for Craniofacial Disorders

    PubMed Central

    Garland, Catharine B.; Pomerantz, Jason H.

    2012-01-01

    Craniofacial disorders present markedly complicated problems in reconstruction because of the complex interactions of the multiple, simultaneously affected tissues. Regenerative medicine holds promise for new strategies to improve treatment of these disorders. This review addresses current areas of unmet need in craniofacial reconstruction and emphasizes how craniofacial tissues differ from their analogs elsewhere in the body. We present a problem-based approach to illustrate current treatment strategies for various craniofacial disorders, to highlight areas of need, and to suggest regenerative strategies for craniofacial bone, fat, muscle, nerve, and skin. For some tissues, current approaches offer excellent reconstructive solutions using autologous tissue or prosthetic materials. Thus, new “regenerative” approaches would need to offer major advantages in order to be adopted. In other tissues, the unmet need is great, and we suggest the greatest regenerative need is for muscle, skin, and nerve. The advent of composite facial tissue transplantation and the development of regenerative medicine are each likely to add important new paradigms to our treatment of craniofacial disorders. PMID:23248598

  12. Biomimetic microenvironments for regenerative endodontics.

    PubMed

    Kaushik, Sagar N; Kim, Bogeun; Walma, Alexander M Cruz; Choi, Sung Chul; Wu, Hui; Mao, Jeremy J; Jun, Ho-Wook; Cheon, Kyounga

    2016-01-01

    Regenerative endodontics has been proposed to replace damaged and underdeveloped tooth structures with normal pulp-dentin tissue by providing a natural extracellular matrix (ECM) mimicking environment; stem cells, signaling molecules, and scaffolds. In addition, clinical success of the regenerative endodontic treatments can be evidenced by absence of signs and symptoms; no bony pathology, a disinfected pulp, and the maturation of root dentin in length and thickness. In spite of the various approaches of regenerative endodontics, there are several major challenges that remain to be improved: a) the endodontic root canal is a strong harbor of the endodontic bacterial biofilm and the fundamental etiologic factors of recurrent endodontic diseases, (b) tooth discolorations are caused by antibiotics and filling materials, (c) cervical root fractures are caused by endodontic medicaments, (d) pulp tissue is not vascularized nor innervated, and (e) the dentin matrix is not developed with adequate root thickness and length. Generally, current clinical protocols and recent studies have shown a limited success of the pulp-dentin tissue regeneration. Throughout the various approaches, the construction of biomimetic microenvironments of pulp-dentin tissue is a key concept of the tissue engineering based regenerative endodontics. The biomimetic microenvironments are composed of a synthetic nano-scaled polymeric fiber structure that mimics native pulp ECM and functions as a scaffold of the pulp-dentin tissue complex. They will provide a framework of the pulp ECM, can deliver selective bioactive molecules, and may recruit pluripotent stem cells from the vicinity of the pulp apex. The polymeric nanofibers are produced by methods of self-assembly, electrospinning, and phase separation. In order to be applied to biomedical use, the polymeric nanofibers require biocompatibility, stability, and biodegradability. Therefore, this review focuses on the development and application of the

  13. Fuel cell having electrolyte

    DOEpatents

    Wright, Maynard K.

    1989-01-01

    A fuel cell having an electrolyte control volume includes a pair of porous opposed electrodes. A maxtrix is positioned between the pair of electrodes for containing an electrolyte. A first layer of backing paper is positioned adjacent to one of the electrodes. A portion of the paper is substantially previous to the acceptance of the electrolyte so as to absorb electrolyte when there is an excess in the matrix and to desorb electrolyte when there is a shortage in the matrix. A second layer of backing paper is positioned adjacent to the first layer of paper and is substantially impervious to the acceptance of electrolyte.

  14. Solid Polymer Electrolyte (SPE) fuel cell technology program

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The overall objectives of the Phase IV Solid Polymer Electrolyte Fuel Cell Technology Program were to: (1) establish fuel cell life and performance at temperatures, pressures and current densities significantly higher than those previously demonstrated; (2) provide the ground work for a space energy storage system based on the solid polymer electrolyte technology (i.e., regenerative H2/O2 fuel cell); (3) design, fabricate and test evaluate a full-scale single cell unit. During this phase, significant progress was made toward the accomplishment of these objectives.

  15. Electrospun Nanofibers for Regenerative Medicine**

    PubMed Central

    Liu, Wenying; Thomopoulos, Stavros

    2013-01-01

    This article reviews recent progress in applying electrospun nanofibers to the emerging field of regenerative medicine. We begin with a brief introduction to electrospinning and nanofibers, with a focus on issues related to the selection of materials, incorporation of bioactive molecules, degradation characteristics, control of mechanical properties, and facilitation of cell infiltration. We then discuss a number of approaches to fabrication of scaffolds from electrospun nanofibers, including techniques for controlling the alignment of nanofibers and for producing scaffolds with complex architectures. We also highlight applications of the nanofiber-based scaffolds in four areas of regenerative medicine that involve nerves, dural tissues, tendons, and the tendon-to-bone insertion site. We conclude this review with perspectives on challenges and future directions for design, fabrication, and utilization of scaffolds based on electrospun nanofibers. PMID:23184683

  16. Regenerative Endodontic Procedures: Clinical Outcomes.

    PubMed

    Diogenes, Anibal; Ruparel, Nikita B

    2017-01-01

    Immature teeth are at risk for pulp necrosis, resulting in arrested root development and poor long-term prognosis. There is growing evidence that regenerative endodontic procedures promote desirable clinical outcomes. Despite significant advances in the field of regenerative endodontics and acceptable clinical outcomes, current evidence suggests that the tissues formed following currently used procedures do not completely recapitulate the former pulp-dentin complex. Further research is needed to identify prognostic factors and predictors of successful outcomes and to develop different treatment strategies to better predictably achieve all identified clinical outcomes, while favoring tissue formation that more closely resembles the pulp-dentin complex. Copyright © 2016. Published by Elsevier Inc.

  17. Regenerative medicine in kidney disease.

    PubMed

    Little, Melissa H; Kairath, Pamela

    2016-08-01

    The treatment of renal failure has changed little in decades. Organ transplantation and dialysis continue to represent the only therapeutic options available. However, decades of fundamental research into the response of the kidney to acute injury and the processes driving progression to chronic kidney disease are beginning to open doors to new options. Similarly, continued investigations into the cellular and molecular basis of normal kidney development, together with major advances in stem cell biology, are now delivering options in regenerative medicine not possible as recently as a decade ago. In this review, we will discuss advances in regenerative medicine as it may be applied to the kidney. This will cover cellular therapies focused on ameliorating injury and improving repair as well as advancements in the generation of new renal tissue from stem/progenitor cells. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  18. Nanotechnology Biomimetic Cartilage Regenerative Scaffolds

    PubMed Central

    Sardinha, Jose Paulo; Myers, Simon

    2014-01-01

    Cartilage has a limited regenerative capacity. Faced with the clinical challenge of reconstruction of cartilage defects, the field of cartilage engineering has evolved. This article reviews current concepts and strategies in cartilage engineering with an emphasis on the application of nanotechnology in the production of biomimetic cartilage regenerative scaffolds. The structural architecture and composition of the cartilage extracellular matrix and the evolution of tissue engineering concepts and scaffold technology over the last two decades are outlined. Current advances in biomimetic techniques to produce nanoscaled fibrous scaffolds, together with innovative methods to improve scaffold biofunctionality with bioactive cues are highlighted. To date, the majority of research into cartilage regeneration has been focused on articular cartilage due to the high prevalence of large joint osteoarthritis in an increasingly aging population. Nevertheless, the principles and advances are applicable to cartilage engineering for plastic and reconstructive surgery. PMID:24883273

  19. Aarhus Regenerative Orthopaedics Symposium (AROS)

    PubMed Central

    Foldager, Casper B; Bendtsen, Michael; Berg, Lise C; Brinchmann, Jan E; Brittberg, Mats; Bunger, Cody; Canseco, Jose; Chen, Li; Christensen, Bjørn B; Colombier, Pauline; Deleuran, Bent W; Edwards, James; Elmengaard, Brian; Farr, Jack; Gatenholm, Birgitta; Gomoll, Andreas H; Hui, James H; Jakobsen, Rune B; Joergensen, Natasja L; Kassem, Moustapha; Koch, Thomas; Kold, Søren; Krogsgaard, Michael R; Lauridsen, Henrik; Le, Dang; Le Visage, Catherine; Lind, Martin; Nygaard, Jens V; Olesen, Morten L; Pedersen, Michael; Rathcke, Martin; Richardson, James B; Roberts, Sally; Rölfing, Jan H D; Sakai, Daisuke; Toh, Wei Seong; Urban, Jill; Spector, Myron

    2016-01-01

    The combination of modern interventional and preventive medicine has led to an epidemic of ageing. While this phenomenon is a positive consequence of an improved lifestyle and achievements in a society, the longer life expectancy is often accompanied by decline in quality of life due to musculoskeletal pain and disability. The Aarhus Regenerative Orthopaedics Symposium (AROS) 2015 was motivated by the need to address regenerative challenges in an ageing population by engaging clinicians, basic scientists, and engineers. In this position paper, we review our contemporary understanding of societal, patient-related, and basic science-related challenges in order to provide a reasoned roadmap for the future to deal with this compelling and urgent healthcare problem. PMID:28271925

  20. CMD kinetics and regenerative medicine

    PubMed Central

    Anjamrooz, Seyed Hadi

    2016-01-01

    The author’s theory of the cell memory disc (CMD) offers a radical and holistic picture of the cell from both functional and structural perspectives. Despite all of the attention that has been focused on different regenerative strategies, several serious CMD-based obstacles still remain that make current cell therapies inherently unethical, harmful, and largely ineffective from a clinical viewpoint. Accordingly, unless there is a real breakthrough in finding an alternative or complementary approach to overcome these barriers, all of the discussion regarding cell-based therapies may be fruitless. Hence, this paper focuses on the issue of CMD kinetics in an attempt to provide a fresh perspective on regenerative medicine. PMID:27186287

  1. The unitized regenerative fuel cell

    SciTech Connect

    1997-05-01

    Fuel cells can operate on hydrogen fuel and oxygen from air. If the fuel cell is designed to also operate in reverse as an electrolyzer, then electricity can be used to convert the water back into hydrogen and oxygen. This dual function system is known as a reversible or unitized regenerative fuel cell. This is an excellent energy source in situations where weight is a concern.

  2. Regenerative Medicine for Battlefield Injuries

    DTIC Science & Technology

    2012-10-01

    that stimulate cartilage reeneraton across a critical size defect (CSD) in a long bone, using the axolotl , Abystoma mexicanum as a model system...of this scaffold was the right one. Experiments grafting axolotl cartilage and muscle to Xenopus tarsal CSDs indicate that the tissues enhance...regenerative response. 15. SUBJECT TERMS- Axolotl hindlimb model, fibula, temporal characterization of fracture repair, characterization of repair of

  3. Regenerative potential of dental pulp.

    PubMed

    Trope, Martin

    2008-07-01

    The regenerative potential of dental pulp, particularly in mature teeth, has been considered extremely limited. However, our improved understanding of pulpal inflammation and repair and improved dental materials and technologies make vital pulp therapy a viable alternative to root canal treatment. This article explores our knowledge in this regard and the future potential of saving or even regenerating the pulp as a routine dental procedure.

  4. Regenerative potential of dental pulp.

    PubMed

    Trope, Martin

    2008-01-01

    The regenerative potential of dental pulp, particularly in mature teeth, has been considered extremely limited. However, our improved understanding of pulpal inflammation and repair and improved dental materials and technologies make vital pulp therapy a viable alternative to root canal treatment. This article explores our knowledge in this regard and the future potential of saving or even regenerating the pulp as a routine dental procedure.

  5. Regenerative endodontics: regeneration or repair?

    PubMed

    Simon, Stéphane R J; Tomson, Phillip L; Berdal, Ariane

    2014-04-01

    Recent advances in biotechnology and translational research have made it possible to provide treatment modalities that protect the vital pulp, allow manipulation of reactionary and reparative dentinogenesis, and, more recently, permit revascularization of an infected root canal space. These approaches are referred to as regenerative procedures. The method currently used to determine the origin of the tissue secreted during the repair/regeneration process is largely based on the identification of cellular markers (usually proteins) left by cells that were responsible for this tissue production. The presence of these proteins in conjunction with other indicators of cellular behavior (especially biomineralization) and analysis of the structure of the newly generated tissue allow conclusions to be made of how it was formed. Thus far, it has not been possible to truly establish the biological mechanism controlling tertiary dentinogenesis. This article considers current therapeutic techniques to treat the dentin-pulp complex and contextualize them in terms of reparative and regenerative processes. Although it may be considered a semantic argument rather than a biological one, the definitions of regeneration and repair are explored to clarify our position in this era of regenerative endodontics. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Regenerative endodontics: A way forward.

    PubMed

    Diogenes, Anibal; Ruparel, Nikita B; Shiloah, Yoav; Hargreaves, Kenneth M

    2016-05-01

    Immature teeth are susceptible to infections due to trauma, anatomic anomalies, and caries. Traditional endodontic therapies for immature teeth, such as apexification procedures, promote resolution of the disease and prevent future infections. However, these procedures fail to promote continued root development, leaving teeth susceptible to fractures. Regenerative endodontic procedures (REPs) have evolved in the past decade, being incorporated into endodontic practice and becoming a viable treatment alternative for immature teeth. The authors have summarized the status of regenerative endodontics on the basis of the available published studies and provide insight into the different levels of clinical outcomes expected from these procedures. Substantial advances in regenerative endodontics are allowing a better understanding of a multitude of factors that govern stem cell-mediated regeneration and repair of the damaged pulp-dentin complex. REPs promote healing of apical periodontitis, continued radiographic root development, and, in certain cases, vitality responses. Despite the clinical success of these procedures, they appear to promote a guided endodontic repair process rather than a true regeneration of physiological-like tissue. Immature teeth with pulpal necrosis with otherwise poor prognosis can be treated with REPs. These procedures do not preclude the possibility of apexification procedures if attempts are unsuccessful. Therefore, REPs may be considered first treatment options for immature teeth with pulpal necrosis. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

  7. Current research on regenerative systems.

    PubMed

    Shapira, J; Mandel, A D; Quattrone, P D; Bell, N L

    1969-01-01

    Multiple studies directed toward the development of a regenerative life support system have shown that easily synthesized organic compounds and microbiological materials are potentially capable of being used as foods for long-duration space missions. Animal feeding studies have supported these views. The organic compounds presently believed to offer the greatest potential are glycerol, simple glycerol derivatives such as triacetin, and formose sugars. Laboratory studies indicate that glycerol can be synthesized from formaldehyde which in turn is obtained by the direct catalytic oxidation of methane, a by-product of the Sabatier reaction used in spacecraft atmosphere control system. Formose sugars are derived from the self-condensation of formaldehyde. Mixtures of glycerol and triacetin have been shown to be suitable as a major component of diets fed to weanling rats for prolonged periods. These compounds do not exist as stereoisomers and therefore offer advantages over the formose sugars. Hydrogenomonas eutropha is the microbiological system under investigation. An automated system for the continuous autotrophic production of Hydrogenomonas bacteria is in operation, and the nutritional requirements for growth in the system using urea as a nitrogen source are being studied. Nutritional evaluation of Hydrogenomonas bacteria has shown they are capable of supplying the total protein requirement of growing rats for prolonged periods. The potential and problems of these regenerative systems and the prospects for the accomplishment of a totally regenerative food system will be discussed.

  8. Fluid and Electrolyte Balance

    MedlinePlus

    ... right balance of electrolytes helps your body's blood chemistry, muscle action and other processes. Sodium, calcium, potassium, chlorine, phosphate and magnesium are all electrolytes. You get them from the foods you eat and the fluids you drink. Levels ...

  9. Molten salt electrolyte separator

    DOEpatents

    Kaun, Thomas D.

    1996-01-01

    A molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication.

  10. Lithium ion conducting electrolytes

    DOEpatents

    Angell, Charles Austen; Liu, Changle; Xu, Kang; Skotheim, Terje A.

    1999-01-01

    The present invention relates generally to highly conductive alkali-metal ion non-crystalline electrolyte systems, and more particularly to novel and unique molten (liquid), rubbery, and solid electrolyte systems which are especially well suited for use with high current density electrolytic cells such as primary and secondary batteries.

  11. Solid polymer electrolyte compositions

    DOEpatents

    Garbe, James E.; Atanasoski, Radoslav; Hamrock, Steven J.; Le, Dinh Ba

    2001-01-01

    An electrolyte composition is featured that includes a solid, ionically conductive polymer, organically modified oxide particles that include organic groups covalently bonded to the oxide particles, and an alkali metal salt. The electrolyte composition is free of lithiated zeolite. The invention also features cells that incorporate the electrolyte composition.

  12. A review on endogenous regenerative technology in periodontal regenerative medicine.

    PubMed

    Chen, Fa-Ming; Zhang, Jing; Zhang, Min; An, Ying; Chen, Fang; Wu, Zhi-Fen

    2010-11-01

    Periodontitis is a globally prevalent inflammatory disease that causes the destruction of the tooth-supporting apparatus and potentially leads to tooth loss. Currently, the methods to reconstitute lost periodontal structures (i.e. alveolar bone, periodontal ligament, and root cementum) have relied on conventional mechanical, anti-infective modalities followed by a range of regenerative procedures such as guided tissue regeneration, the use of bone replacement grafts and exogenous growth factors (GFs), and recently developed tissue engineering technologies. However, all current or emerging paradigms have either been shown to have limited and variable outcomes or have yet to be developed for clinical use. To accelerate clinical translation, there is an ongoing need to develop therapeutics based on endogenous regenerative technology (ERT), which can stimulate latent self-repair mechanisms in patients and harness the host's innate capacity for regeneration. ERT in periodontics applies the patient's own regenerative 'tools', i.e. patient-derived GFs and fibrin scaffolds, sometimes in association with commercialized products (e.g. Emdogain and Bio-Oss), to create a material niche in an injured site where the progenitor/stem cells from neighboring tissues can be recruited for in situ periodontal regeneration. The choice of materials and the design of implantable devices influence therapeutic potential and the number and invasiveness of the associated clinical procedures. The interplay and optimization of each niche component involved in ERT are particularly important to comprehend how to make the desired cell response safe and effective for therapeutics. In this review, the emerging opportunities and challenges of ERT that avoid the ex vivo culture of autologous cells are addressed in the context of new approaches for engineering or regeneration of functional periodontal tissues by exploiting the use of platelet-rich products and its associated formulations as key

  13. Nanoporous polymer electrolyte

    DOEpatents

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  14. Electrolyte vapor condenser

    DOEpatents

    Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

    1983-02-08

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

  15. Regenerative fuel cells for use in Space Stations

    NASA Astrophysics Data System (ADS)

    Benz, Uwe; Tillmetz, Werner

    1990-10-01

    The conversion and storage of energy with high efficiency and high energy density, respectively, will be an important factor in future space activities as well as for terrestrial applications. The basic concepts of a regenerative fuel cell system (RFCS) based on the immobile alkaline electrolyte technology, which has been identified as the most promising technology for space application, are presented. A system optimization with respect to a minimum overall mass has been performed, and the main design data are given. Some system engineering aspects are discussed, as well as possible interfaces to other space systems. A brief comparison shows that even from a system-mass point of view the RFCS has an advantage over batteries.

  16. Alkaline regenerative fuel cell systems for energy storage

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Reid, M. A.; Martin, R. E.

    1981-01-01

    A description is presented of the results of a preliminary design study of a regenerative fuel cell energy storage system for application to future low-earth orbit space missions. The high energy density storage system is based on state-of-the-art alkaline electrolyte cell technology and incorporates dedicated fuel cell and electrolysis cell modules. In addition to providing energy storage, the system can provide hydrogen and oxygen for attitude control of the satellite and for life support. During the daylight portion of the orbit the electrolysis module uses power provided by the solar array to generate H2 and O2 from the product water produced by the fuel cell module. The fuel cell module supplies electrical power during the dark period of the orbit.

  17. Alkaline regenerative fuel cell systems for energy storage

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Reid, M. A.; Martin, R. E.

    1981-01-01

    A description is presented of the results of a preliminary design study of a regenerative fuel cell energy storage system for application to future low-earth orbit space missions. The high energy density storage system is based on state-of-the-art alkaline electrolyte cell technology and incorporates dedicated fuel cell and electrolysis cell modules. In addition to providing energy storage, the system can provide hydrogen and oxygen for attitude control of the satellite and for life support. During the daylight portion of the orbit the electrolysis module uses power provided by the solar array to generate H2 and O2 from the product water produced by the fuel cell module. The fuel cell module supplies electrical power during the dark period of the orbit.

  18. Regenerative Engineering and Bionic Limbs

    PubMed Central

    James, Roshan; Laurencin, Cato T.

    2015-01-01

    Amputations of the upper extremity are severely debilitating, current treatments support very basic limb movement, and patients undergo extensive physiotherapy and psychological counselling. There is no prosthesis that allows the amputees near-normal function. With increasing number of amputees due to injuries sustained in accidents, natural calamities and international conflicts, there is a growing requirement for novel strategies and new discoveries. Advances have been made in technological, material and in prosthesis integration where researchers are now exploring artificial prosthesis that integrate with the residual tissues and function based on signal impulses received from the residual nerves. Efforts are focused on challenging experts in different disciplines to integrate ideas and technologies to allow for the regeneration of injured tissues, recording on tissue signals and feed-back to facilitate responsive movements and gradations of muscle force. A fully functional replacement and regenerative or integrated prosthesis will rely on interface of biological process with robotic systems to allow individual control of movement such as at the elbow, forearm, digits and thumb in the upper extremity. Regenerative engineering focused on the regeneration of complex tissue and organ systems will be realized by the cross-fertilization of advances over the past thirty years in the fields of tissue engineering, nanotechnology, stem cell science, and developmental biology. The convergence of toolboxes crated within each discipline will allow interdisciplinary teams from engineering, science, and medicine to realize new strategies, mergers of disparate technologies, such as biophysics, smart bionics, and the healing power of the mind. Tackling the clinical challenges, interfacing the biological process with bionic technologies, engineering biological control of the electronic systems, and feed-back will be the important goals in regenerative engineering over the next

  19. Advanced regenerative absorption refrigeration cycles

    DOEpatents

    Dao, Kim

    1990-01-01

    Multi-effect regenerative absorption cycles which provide a high coefficient of performance (COP) at relatively high input temperatures. An absorber-coupled double-effect regenerative cycle (ADR cycle) (10) is provided having a single-effect absorption cycle (SEA cycle) (11) as a topping subcycle and a single-effect regenerative absorption cycle (1R cycle) (12) as a bottoming subcycle. The SEA cycle (11) includes a boiler (13), a condenser (21), an expansion device (28), an evaporator (31), and an absorber (40), all operatively connected together. The 1R cycle (12) includes a multistage boiler (48), a multi-stage resorber (51), a multisection regenerator (49) and also uses the condenser (21), expansion device (28) and evaporator (31) of the SEA topping subcycle (11), all operatively connected together. External heat is applied to the SEA boiler (13) for operation up to about 500 degrees F., with most of the high pressure vapor going to the condenser (21) and evaporator (31) being generated by the regenerator (49). The substantially adiabatic and isothermal functioning of the SER subcycle (12) provides a high COP. For higher input temperatures of up to 700 degrees F., another SEA cycle (111) is used as a topping subcycle, with the absorber (140) of the topping subcycle being heat coupled to the boiler (13) of an ADR cycle (10). The 1R cycle (12) itself is an improvement in that all resorber stages (50b-f) have a portion of their output pumped to boiling conduits (71a-f) through the regenerator (49), which conduits are connected to and at the same pressure as the highest pressure stage (48a) of the 1R multistage boiler (48).

  20. Regenerative Engineering and Bionic Limbs.

    PubMed

    James, Roshan; Laurencin, Cato T

    2015-03-01

    Amputations of the upper extremity are severely debilitating, current treatments support very basic limb movement, and patients undergo extensive physiotherapy and psychological counselling. There is no prosthesis that allows the amputees near-normal function. With increasing number of amputees due to injuries sustained in accidents, natural calamities and international conflicts, there is a growing requirement for novel strategies and new discoveries. Advances have been made in technological, material and in prosthesis integration where researchers are now exploring artificial prosthesis that integrate with the residual tissues and function based on signal impulses received from the residual nerves. Efforts are focused on challenging experts in different disciplines to integrate ideas and technologies to allow for the regeneration of injured tissues, recording on tissue signals and feed-back to facilitate responsive movements and gradations of muscle force. A fully functional replacement and regenerative or integrated prosthesis will rely on interface of biological process with robotic systems to allow individual control of movement such as at the elbow, forearm, digits and thumb in the upper extremity. Regenerative engineering focused on the regeneration of complex tissue and organ systems will be realized by the cross-fertilization of advances over the past thirty years in the fields of tissue engineering, nanotechnology, stem cell science, and developmental biology. The convergence of toolboxes crated within each discipline will allow interdisciplinary teams from engineering, science, and medicine to realize new strategies, mergers of disparate technologies, such as biophysics, smart bionics, and the healing power of the mind. Tackling the clinical challenges, interfacing the biological process with bionic technologies, engineering biological control of the electronic systems, and feed-back will be the important goals in regenerative engineering over the next

  1. [Chondrocytes application in regenerative medicine].

    PubMed

    Dziedzic, Katarzyna; Zalewski, Mateusz; Gadek, Artur; Drukała, Justyna

    2014-01-01

    Cartilage reconstruction is a crucial issue for tissue engineering because of high damage frequency in connection with low regenerative capacity. Microfractures and shaving are the oldest and most commonly used practices. The newest techniques are: Autologous Chondrocyte Implantation, Matrix Associated Chondrocytes Implantation and their derivatives. Dedifferentiation of chondrocytes due to low proliferation rate and phenotype loss makes isolation and in vitro culture of normal human chondrocytes very complex. Therefore, obtaining mesenchymal stem cells from various sources and differentiating them into chondrocytes is another interesting approach.

  2. The imperative for regenerative agriculture.

    PubMed

    Rhodes, Christopher J

    2017-03-01

    A review is made of the current state of agriculture, emphasising issues of soil erosion and dependence on fossil fuels, in regard to achieving food security for a relentlessly enlarging global population. Soil has been described as "the fragile, living skin of the Earth", and yet both its aliveness and fragility have all too often been ignored in the expansion of agriculture across the face of the globe. Since it is a pivotal component in a global nexus of soil-water-air-energy, how we treat the soil can impact massively on climate change - with either beneficial or detrimental consequences, depending on whether the soil is preserved or degraded. Regenerative agriculture has at its core the intention to improve the health of soil or to restore highly degraded soil, which symbiotically enhances the quality of water, vegetation and land-productivity. By using methods of regenerative agriculture, it is possible not only to increase the amount of soil organic carbon (SOC) in existing soils, but to build new soil. This has the effect of drawing down carbon from the atmosphere, while simultaneously improving soil structure and soil health, soil fertility and crop yields, water retention and aquifer recharge - thus ameliorating both flooding and drought, and also the erosion of further soil, since runoff is reduced. Since food production on a more local scale is found to preserve the soil and its quality, urban food production should be seen as a significant potential contributor to regenerative agriculture in the future, so long as the methods employed are themselves 'regenerative'. If localisation is to become a dominant strategy for dealing with a vastly reduced use of fossil fuels, and preserving soil quality - with increased food production in towns and cities - it will be necessary to incorporate integrated ('systems') design approaches such as permaculture and the circular economy (which minimise and repurpose 'waste') within the existing urban infrastructure. In

  3. Regenerative superheated steam turbine cycles

    NASA Technical Reports Server (NTRS)

    Fuller, L. C.; Stovall, T. K.

    1980-01-01

    PRESTO computer program was developed to analyze performance of wide range of steam turbine cycles with special attention given to regenerative superheated steam turbine cycles. It can be used to model standard turbine cycles, including such features as process steam extraction, induction and feedwater heating by external sources, peaking, and high back pressure. Expansion line efficiencies, exhaust loss, leakages, mechanical losses, and generator losses are used to calculate cycle heat rate and generator output. Program provides power engineer with flexible aid for design and analysis of steam turbine systems.

  4. Regenerative Simulation Using Internal Controls.

    DTIC Science & Technology

    1982-01-01

    VSIYIRSITY OT 21A AT AUSTIN Decnber, 1982 .. ;ɟ Ilk Copyright by Jan Dnise Eakie 1982 To T.M., T.J,, and T.B. 4] ACKNOWLEDGEMENTS Dr . James R. Wilson...was the supervising pro- fessor for this research. Without his guidance and support, none of this would have been possible. I also wish to thank Dr . W.G...Lesso, Dr . P.A. Jensen, and Dr . R. Sullivan for their assistance as members of my graduate committee. 9| REGENERATIVE SIMULATION USING INTERNAL

  5. Wavelength tunable alexandrite regenerative amplifier

    SciTech Connect

    Harter, D.J.; Bado, P.

    1988-11-01

    We describe a wavelength tunable alexandrite regenerative amplifier which is used to amplify nanosecond slices from a single-frequency cw dye laser or 50-ps pulses emitted by a diode laser to energies in the 10-mJ range. The amplified 5-ns slices generated by the cw-pumped line narrowed dye laser are Fourier transform limited. The 50-ps pulses emitted by a gain-switched diode laser are amplified by more than 10 orders of magnitude in a single stage.

  6. Regenerative superheated steam turbine cycles

    NASA Technical Reports Server (NTRS)

    Fuller, L. C.; Stovall, T. K.

    1980-01-01

    PRESTO computer program was developed to analyze performance of wide range of steam turbine cycles with special attention given to regenerative superheated steam turbine cycles. It can be used to model standard turbine cycles, including such features as process steam extraction, induction and feedwater heating by external sources, peaking, and high back pressure. Expansion line efficiencies, exhaust loss, leakages, mechanical losses, and generator losses are used to calculate cycle heat rate and generator output. Program provides power engineer with flexible aid for design and analysis of steam turbine systems.

  7. Entropy Generation in Regenerative Systems

    NASA Technical Reports Server (NTRS)

    Kittel, Peter

    1995-01-01

    Heat exchange to the oscillating flows in regenerative coolers generates entropy. These flows are characterized by oscillating mass flows and oscillating temperatures. Heat is transferred between the flow and heat exchangers and regenerators. In the former case, there is a steady temperature difference between the flow and the heat exchangers. In the latter case, there is no mean temperature difference. In this paper a mathematical model of the entropy generated is developed for both cases. Estimates of the entropy generated by this process are given for oscillating flows in heat exchangers and in regenerators. The practical significance of this entropy is also discussed.

  8. Feasibility study of a simple unitized regenerative fuel cell

    NASA Astrophysics Data System (ADS)

    Verma, A.; Basu, S.

    Conventional fuel cells use hydrogen and oxygen as the fuel and oxidant, respectively. Hydrogen and oxygen can be produced through electrolysis of water in an electrochemical cell. A simple unitized regenerative fuel cell (URFC), by combining an electrolyzer and a fuel cell, is constructed to check the feasibility of such a device. In the first cycle, hydrogen and oxygen gases are generated from water containing NaHCO 3 when a given dc voltage is applied across Ni-Co/stainless steel electrodes. A solar photovoltaic cell is also used to provide the power. The generated gases are trapped between their respective electrodes and nylon mesh. In the second cycle, the hydrogen and oxygen gases are used in the same electrochemical cell (fuel cell) to produce electricity under a specific load. The current density and voltage are measured by varying different parameters, e.g., time of electrolysis, magnitude of voltage applied, and electrolyte concentration. An open-circuit voltage (OCV) of 1.3 V is obtained from two regenerative fuel cells in series with a total active electrode area of 300 cm 2. A current density of about 0.5 mA cm -2 is generated using 0.5N NaHCO 3 when 4.5 V is applied for 25 min. A maximum power of 36.5 mW is obtained at 0.21 mA cm -2.

  9. Regenerative Medicine in Alzheimer's Disease

    PubMed Central

    Felsenstein, Kevin M.; Candelario, Kate M.; Steindler, Dennis A.; Borchelt, David R.

    2013-01-01

    Identifying novel, effective therapeutics for Alzheimer's disease (AD) is one of the major unmet medical needs for the coming decade. Because the current paradigm for developing and testing disease modifying AD therapies is protracted and likely to be even longer with the shift towards earlier intervention in pre-clinical AD, it is an open question whether we can develop, test, and widely deploy a novel therapy in time to help the current at-risk generation if we continue to follow the standard paradigms of discovery and drug development. There is an imperative need to find safe and effective preventative measures that can be rapidly deployed to stem the coming wave of AD that will potentially engulf the next generation. We can broadly define regenerative medicine as approaches that use stem-cell-based therapies or approaches that seek to modulate inherent neurogenesis. Neurogenesis, though most active during pre-natal development has been shown to continue in several small parts of the brain, which includes the hippocampus and the subventricular zone, suggesting its potential to reverse cognitive deficits. If AD pathology impacts neurogenesis then it follows that conditions that stimulate endogenous neurogenesis (e.g., environmental stimuli, physical activity, trophic factors, cytokines, and drugs) may help to promote the regenerative and recovery process. Herein, we review the complex logistics of potentially implementing neurogenesis-based therapeutic strategies for the treatment of AD. PMID:24286919

  10. Optimal performance of regenerative cryocoolers

    NASA Astrophysics Data System (ADS)

    de Boer, P. C. T.

    2011-02-01

    The key component of a regenerative cryocooler is its regenerative heat exchanger. This device is subject to losses due to imperfect heat transfer between the regenerator material and the gas, as well as due to viscous dissipation. The relative magnitudes of these losses can be characterized by the ratio of the Stanton number St to the Fanning friction factor f. Using available data for the ratio St/ f, results are developed for the optimal cooling rate and Carnot efficiency. The variations of pressure and temperature are taken to be sinusoidal in time, and to have small amplitudes. The results are applied to the case of the Stirling cryocooler, with flow being generated by pistons at both sides of the regenerator. The performance is found to be close to optimal at large ratio of the warm space volume to the regenerator void volume. The results are also applied to the Orifice Pulse Tube Refrigerator. In this case, optimal performance additionally requires a large ratio of the regenerator void volume to the cold space volume.

  11. Changes in Regenerative Capacity through Lifespan

    PubMed Central

    Yun, Maximina H.

    2015-01-01

    Most organisms experience changes in regenerative abilities through their lifespan. During aging, numerous tissues exhibit a progressive decline in homeostasis and regeneration that results in tissue degeneration, malfunction and pathology. The mechanisms responsible for this decay are both cell intrinsic, such as cellular senescence, as well as cell-extrinsic, such as changes in the regenerative environment. Understanding how these mechanisms impact on regenerative processes is essential to devise therapeutic approaches to improve tissue regeneration and extend healthspan. This review offers an overview of how regenerative abilities change through lifespan in various organisms, the factors that underlie such changes and the avenues for therapeutic intervention. It focuses on established models of mammalian regeneration as well as on models in which regenerative abilities do not decline with age, as these can deliver valuable insights for our understanding of the interplay between regeneration and aging. PMID:26512653

  12. Changes in Regenerative Capacity through Lifespan.

    PubMed

    Yun, Maximina H

    2015-10-23

    Most organisms experience changes in regenerative abilities through their lifespan. During aging, numerous tissues exhibit a progressive decline in homeostasis and regeneration that results in tissue degeneration, malfunction and pathology. The mechanisms responsible for this decay are both cell intrinsic, such as cellular senescence, as well as cell-extrinsic, such as changes in the regenerative environment. Understanding how these mechanisms impact on regenerative processes is essential to devise therapeutic approaches to improve tissue regeneration and extend healthspan. This review offers an overview of how regenerative abilities change through lifespan in various organisms, the factors that underlie such changes and the avenues for therapeutic intervention. It focuses on established models of mammalian regeneration as well as on models in which regenerative abilities do not decline with age, as these can deliver valuable insights for our understanding of the interplay between regeneration and aging.

  13. Lessons from developmental biology for regenerative medicine.

    PubMed

    Turner, Neill J; Keane, Timothy J; Badylak, Stephen F

    2013-09-01

    The ultimate goal of regenerative medicine is the functional restoration of lost or damaged tissues and organs. Since most tissues in man lack true regenerative properties and instead respond to injury with an inflammatory response and scar tissue formation, regenerative medicine strategies that include combinations of cells, scaffolds, and bioactive molecules to replace injured or missing tissues have been developed. The physical, chemical, and electrical cues that define the microenvironmental niche and the effect of these influences upon cell behavior during development are of interest to developmental biologists, with obvious overlap to the interest of the regenerative medicine field. This manuscript provides an overview of current approaches for tissue restoration being investigated in the field of regenerative medicine and attempts to identify areas of mutual beneficial interest with the field of developmental biology.

  14. Ceramic electrolyte coating methods

    DOEpatents

    Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

    2004-10-12

    Processes for preparing aqueous suspensions of a nanoscale ceramic electrolyte material such as yttrium-stabilized zirconia. The invention also includes a process for preparing an aqueous coating slurry of a nanoscale ceramic electrolyte material. The invention further includes a process for depositing an aqueous spray coating slurry including a ceramic electrolyte material on pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

  15. Electrolytic purification of metals

    DOEpatents

    Bowman, Kenneth A.

    1980-01-01

    A method of electrolytically separating metal from impurities comprises providing the metal and impurities in a molten state in a container having a porous membrane therein, the membrane having a thickness in the range of about 0.01 to 0.1 inch, being capable of containing the molten metal in the container, and being permeable by a molten electrolyte. The metal is electrolytically transferred through the membrane to a cathode in the presence of the electrolyte for purposes of separating or removing impurities from the metal.

  16. Hydrogen-oxygen flame acceleration and transition to detonation in channels with no-slip walls for a detailed chemical reaction model.

    PubMed

    Ivanov, M F; Kiverin, A D; Liberman, M A

    2011-05-01

    The features of flame acceleration in channels with wall friction and the deflagration to detonation transition (DDT) are investigated theoretically and using high resolution numerical simulations of two-dimensional reactive Navier-Stokes equations, including the effects of viscosity, thermal conduction, molecular diffusion, and a detailed chemical reaction mechanism for hydrogen-oxygen gaseous mixture. It is shown that in a wide channel, from the beginning, the flame velocity increases exponentially for a short time and then flame acceleration decreases, ending up with the abrupt increase of the combustion wave velocity and the actual transition to detonation. In a thin channel with a width smaller than the critical value, the exponential increase of the flame velocity is not bounded and ends up with the transition to detonation. The transition to detonation occurs due to the pressure pulse, which is formed at the tip of the accelerating flame. The amplitude of the pressure pulse grows exponentially due to a positive feedback coupling between the pressure pulse and the heat released in the reaction. Finally, large amplitude pressure pulse steepens into a strong shock coupled with the reaction zone forming the overdriven detonation. The evolution from a temperature gradient to a detonation via the Zeldovich gradient mechanism and its applicability to the deflagration-to-detonation transition is investigated for combustible materials whose chemistry is governed by chain-branching kinetics. The results of the high resolution simulations are fully consistent with experimental observations of the flame acceleration and DDT. © 2011 American Physical Society

  17. Detailed Simulations of Shock-Bifurcation and Ignition of an Argon-diluted Hydrogen/Oxygen Mixture in a Shock Tube

    SciTech Connect

    Ihme, Matthias; Sun, Yong; Deiterding, Ralf

    2013-01-01

    Detailed simulations of the bifurcation and ignition of an Argon-diluted Hydrogen/Oxygen mixture in the two-stage weak ignition regime are performed. An adaptive mesh-refinement (AMR) technique is employed to resolve all relevant physical scales that are associated with the viscous boundary-layer, the reaction front, and the shock-wave. A high-order hybrid WENO/central-differencing method is used as spatial discretization scheme, and a detailed chemical mechanism is employed to describe the combustion of the H2/O2 mixture. The operating conditions considered in this study are p = 5 bar and T = 1100 K, and fall in the third explosion limit. The computations show that the mixing of the thermally stratified fluid, carrying different momentum and enthalpy, introduces inhomogeneities in the core-region behind the reflected shock. These inhomogeneities act as localized ignition kernels. During the induction period, these kernels slowly expand and eventually transition to a detonation wave that rapidly consumes the unburned mixture.In competition with this detonation wave are the presence of secondary ignition kernels that appear in the unreacted core-region between reflected shock and detonation wave.

  18. The prediction of nozzle performance and heat transfer in hydrogen/oxygen rocket engines with transpiration cooling, film cooling, and high area ratios

    NASA Technical Reports Server (NTRS)

    Kacynski, Kenneth J.; Hoffman, Joe D.

    1993-01-01

    An advanced engineering computational model has been developed to aid in the analysis and design of hydrogen/oxygen chemical rocket engines. The complete multi-species, chemically reacting and diffusing Navier-Stokes equations are modelled, finite difference approach that is tailored to be conservative in an axisymmetric coordinate system for both the inviscid and viscous terms. Demonstration cases are presented for a 1030:1 area ratio nozzle, a 25 lbf film cooled nozzle, and transpiration cooled plug-and-spool rocket engine. The results indicate that the thrust coefficient predictions of the 1030:1 nozzle and the film cooled nozzle are within 0.2 to 0.5 percent, respectively, of experimental measurements when all of the chemical reaction and diffusion terms are considered. Further, the model's predictions agree very well with the heat transfer measurements made in all of the nozzle test cases. The Soret thermal diffusion term is demonstrated to have a significant effect on the predicted mass fraction of hydrogen along the wall of the nozzle in both the laminar flow 1030:1 nozzle and the turbulent plug-and-spool rocket engine analysis cases performed. Further, the Soret term was shown to represent a significant fraction of the diffusion fluxes occurring in the transpiration cooled rocket engine.

  19. The destruction chemistry of organophosphorus compounds in flames -- I: Quantitative determination of final phosphorus-containing species in hydrogen-oxygen flames

    SciTech Connect

    Korobeinichev, O.P.; Ilyin, S.B.; Shvartsberg, V.M.; Chernov, A.A.

    1999-09-01

    The combustion of organophosphorus compounds (OPC) is of considerable interest in connection with the disposal of toxic and hazardous chemical wastes and other undesirable substances containing phosphorus, including chemical warfare agents (CWA) such as the nerve agents sarin and VX. This paper presents the results of a quantitative determination of the composition of final phosphorus-containing products (PO, PO{sub 2}, HOPO, and HOPO{sub 2}) from the destruction of the organophosphorus compounds trimethyl phosphate (TMP) and dimethyl methylphosphonate (DMMP) in premixed hydrogen-oxygen flames. The flames were stabilized on a flat burner at 47 Torr and probed using molecular beam mass spectrometric techniques. Quantitative analysis of these species is difficult, due to problems with mass spectrometric calibrations. Also these compounds are unstable under normal conditions and are not readily available To solve this problem a material balance equation for the element phosphorus has been used to analyze the results is stoichiometric, rich, and lean flames, doped with different amounts of TMP and DMMP. A system of linear nondegenerate materials balance equations was solved using the Singular Value Decomposition (SVD) algorithm. The calculated calibration coefficients for the phosphorus species have allowed their mole fractions to be derived. How the concentrations of PO, PO{sub 2}, HOPO, and HOPI{sub 2} depend on the initial concentrations of DMMP or TMP and on the mixture's composition has been studied. The measurements are compared to the Results of thermochemical equilibrium calculations.

  20. Regenerative Electroless Etching of Silicon.

    PubMed

    Kolasinski, Kurt W; Gimbar, Nathan J; Yu, Haibo; Aindow, Mark; Mäkilä, Ermei; Salonen, Jarno

    2017-01-09

    Regenerative electroless etching (ReEtching), described herein for the first time, is a method of producing nanostructured semiconductors in which an oxidant (Ox1 ) is used as a catalytic agent to facilitate the reaction between a semiconductor and a second oxidant (Ox2 ) that would be unreactive in the primary reaction. Ox2 is used to regenerate Ox1 , which is capable of initiating etching by injecting holes into the semiconductor valence band. Therefore, the extent of reaction is controlled by the amount of Ox2 added, and the rate of reaction is controlled by the injection rate of Ox2 . This general strategy is demonstrated specifically for the production of highly luminescent, nanocrystalline porous Si from the reaction of V2 O5 in HF(aq) as Ox1 and H2 O2 (aq) as Ox2 with Si powder and wafers.

  1. Variable ratio regenerative braking device

    DOEpatents

    Hoppie, Lyle O.

    1981-12-15

    Disclosed is a regenerative braking device (10) for an automotive vehicle. The device includes an energy storage assembly (12) having a plurality of rubber rollers (26, 28) mounted for rotation between an input shaft (36) and an output shaft (42), clutches (38, 46) and brakes (40, 48) associated with each shaft, and a continuously variable transmission (22) connectable to a vehicle drivetrain and to the input and output shafts by the respective clutches. The rubber rollers are torsionally stressed to accumulate energy from the vehicle when the input shaft is clutched to the transmission while the brake on the output shaft is applied, and are torsionally relaxed to deliver energy to the vehicle when the output shaft is clutched to the transmission while the brake on the input shaft is applied. The transmission ratio is varied to control the rate of energy accumulation and delivery for a given rotational speed of the vehicle drivetrain.

  2. [Regenerative medicine: history and perspectives].

    PubMed

    Okabayashi, Koji; Asashima, Makoto

    2008-05-01

    Regenerative medicine using stem cells is one of the most important topics today. Embryonic stem cells (ES cells) are useful in the studies of the differentiation of various cells or tissues for transplantation therapy, because of their pluripotency to differentiate into almost all types of cells in the body. However, it is controversial to use human ES cells, because it is necessary to sacrifice the life of human embryos for the establishment of these cells. Induced pluripotent stem cells (iPS cells) generated from somatic cells of patients are one of the alternative sources of human pluripotent stem cells while avoiding ethical problems. Epigenetic studies using iPS cells may be valuable to find the way to control cell differentiation more effectively.

  3. Unitized regenerative fuel cell systems

    SciTech Connect

    Mitlitsky, F; Molter, T M; Myers, B; Weisberg, A H

    1998-09-10

    Energy storage systems with extremely high specific energy (>400 Wh/kg) have been designed that use lightweight pressure vessels to contain the gases generated by reversible (unitized) regenerative fuel cells (URFCs).[1] URFC systems are being designed and developed for a variety of applications, including high altitude long endurance (HALE) solar rechargeable aircraft (SRA), zero emission vehicles (ZEVs), hybrid energy storage/propulsion systems for spacecraft, energy storage for remote (off-grid) power sources, and peak shaving for on-grid applications.[1-10] Energy storage for HALE SRA was the original application for this set of innovations, and a prototype solar powered aircraft (Pathfinder-Plus) recently set another altitude record for all propeller-driven aircraft on August 6, 1998, when it flew to 80,285 feet (24.47 km).[11

  4. Modeling regenerative braking and storage for vehicles

    SciTech Connect

    Wicks, F.; Donnelly, K.

    1997-12-31

    The fuel savings benefits of regenerative braking and storage for vehicles are often described but not quantified. For example, the federal government and automobile manufacturers are sponsoring a Program for a New Generation of Vehicles (PGNV) with a goal of obtaining a performance of 80 mpg in a family size car. It is typically suggested that such a vehicle will be a hybrid engine and electric drive with regenerative braking. The authors note that while regenerative braking has the potential of saving fuel, it may also do more harm than good as a result of additional weight, less than ideal charge/discharge efficiency on the batteries or storage flywheels and the limited portion of the entire driving cycle when regenerative braking can be utilized. The authors also noted that if regenerative braking can have a net benefit, it would be on a heavy vehicle such as a municipal bus because of the frequent stop and go requirements for both traffic light and passengers. Thus the authors initiated a study of regenerative braking on such a vehicle. The resulting analysis presented in this paper includes data following municipal buses to define the driving cycle, modeling the bus power requirements from weight, aerodynamics and rolling resistance, and then calculating the fuel saving that could result from an ideal regenerative braking system.

  5. Molten salt electrolyte separator

    DOEpatents

    Kaun, T.D.

    1996-07-09

    The patent describes a molten salt electrolyte/separator for battery and related electrochemical systems including a molten electrolyte composition and an electrically insulating solid salt dispersed therein, to provide improved performance at higher current densities and alternate designs through ease of fabrication. 5 figs.

  6. Prediction of Enthalpy of Formation in the Solid State (at 298.15 K) using Second-Order Group Contributions. Part 1. Carbon-Hydrogen and Carbon-Hydrogen-Oxygen Compounds

    NASA Astrophysics Data System (ADS)

    Salmon, Anna; Dalmazzone, Didier

    2006-09-01

    A predictive method, based on Benson's group additivity technique, is developed for calculating the enthalpy of formation in the solid phase, at 298.15K, of carbon-hydrogen compounds and carbon-hydrogen-oxygen compounds. A complete database compiles 398 experimental enthalpies of formation. The whole group contribution values, ring strain corrections, and nonnearest neighbor interactions evaluated are listed. Finally a comparison with Cohen's method indicates that this new estimation method leads to higher precision and reliability.

  7. Alkaline regenerative fuel cell energy storage system for manned orbital satellites

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Gitlow, B.; Sheibley, D. W.

    1982-01-01

    It is pointed out that the alkaline regenerative fuel cell system represents a highly efficient, lightweight, reliable approach for providing energy storage in an orbiting satellite. In addition to its energy storage function, the system can supply hydrogen and oxygen for attitude control of the satellite and for life support. A summary is presented of the results to date obtained in connection with the NASA-sponsored fuel cell technology advancement program, giving particular attention to the requirements of the alkaline regenerative fuel cell and the low-earth mission. Attention is given to system design guidelines, weight considerations, gold-platinum cathode cell performance, matrix development, the electrolyte reservoir plate, and the cyclical load profile tests.

  8. Alkaline regenerative fuel cell energy storage system for manned orbital satellites

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Gitlow, B.; Sheibley, D. W.

    1982-01-01

    It is pointed out that the alkaline regenerative fuel cell system represents a highly efficient, lightweight, reliable approach for providing energy storage in an orbiting satellite. In addition to its energy storage function, the system can supply hydrogen and oxygen for attitude control of the satellite and for life support. A summary is presented of the results to date obtained in connection with the NASA-sponsored fuel cell technology advancement program, giving particular attention to the requirements of the alkaline regenerative fuel cell and the low-earth mission. Attention is given to system design guidelines, weight considerations, gold-platinum cathode cell performance, matrix development, the electrolyte reservoir plate, and the cyclical load profile tests.

  9. Stem cell research and regenerative medicine in 2014: first year of regenerative medicine in Japan.

    PubMed

    Okano, Hideyuki

    2014-09-15

    It is my great pleasure to announce that we were able to publish the Japan Issue in Stem Cells and Development, especially in this year 2014. This year, 2014, is said to be the First Year of Regenerative Medicine in Japan. This movement is likely to be based on the establishment of a new law system regarding regenerative medicine (an Act for Ensuring the Safety of Regenerative Medicine or the so-called Regenerative Medicine Law) and the partial revision of the Pharmaceutical Affairs Law (PAL). Both laws will come into effect in 2014 in this country. These new law systems are expected to have a great impact on the facilitation of R&D related to regenerative medicine and stem cell biology. In the present Japan Issue, some excellent stem cell research in this country will be introduced to celebrate the First Year of Regenerative Medicine in Japan.

  10. Regenerative medicine: a primer for paediatricians.

    PubMed

    Polak, Dame Julia M

    2009-11-01

    Regenerative medicine is a multidisciplinary field concerned with the replacement, repair or restoration of injured tissues. Cell therapy and tissue engineering are part of the broader remit of regenerative medicine. The ultimate aim is to provide safe and efficient therapies for a large number of clinical conditions. Novel regenerative therapies are already in use in initial clinical trials. The main components of regenerative medicine are cells and specially designed materials. A vast variety of cells types are currently used including: adult and stem cells. Equally a large number of natural and man-made materials have been investigated. Despite of considerable advances many challenges lie ahead. These are summarised in this review article. The field is slowly maturing and the initial unhelpful hype has been replaced by a more measured, mature and realistic outlook.

  11. Regenerative medicine applications in combat casualty care.

    PubMed

    Fleming, Mark E; Bharmal, Husain; Valerio, Ian

    2014-03-01

    The purpose of this report is to describe regenerative medicine applications in the management of complex injuries sustained by service members injured in support of the wars in Afghanistan and Iraq. Improvements in body armor, resuscitative techniques and faster transport have translated into increased patient survivability and more complex wounds. Combat-related blast injuries have resulted in multiple extremity injuries, significant tissue loss and amputations. Due to the limited availability and morbidity associated with autologous tissue donor sites, the introduction of regenerative medicine has been critical in managing war extremity injuries with composite massive tissue loss. Through case reports and clinical images, this report reviews the application of regenerative medicine modalities employed to manage combat-related injuries. It illustrates that the novel use of hybrid reconstructions combining traditional and regenerative medicine approaches are an effective tool in managing wounds. Lessons learned can be adapted to civilian care.

  12. Applications of regenerative medicine in organ transplantation.

    PubMed

    Jain, Aditya; Bansal, Ramta

    2015-01-01

    A worldwide shortage of organs for clinical implantation establishes the need to bring forward and test new technologies that will help in solving the problem. The concepts of regenerative medicine hold the potential for augmenting organ function or repairing damaged organ or allowing regeneration of deteriorated organs and tissue. Researchers are exploring possible regenerative medicine applications in organ transplantation so that coming together of the two fields can benefit each other. The present review discusses the strategies that are being implemented to regenerate or bio-engineer human organs for clinical purposes. It also highlights the limitations of the regenerative medicine that needs to be addressed to explore full potential of the field. A web-based research on MEDLINE was done using keywords "regenerative medicine," "tissue-engineering," "bio-engineered organs," "decellularized scaffold" and "three-dimensional printing." This review screened about 170 articles to get the desired knowledge update.

  13. High power regenerative laser amplifier

    DOEpatents

    Miller, J.L.; Hackel, L.A.; Dane, C.B.; Zapata, L.E.

    1994-02-08

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.

  14. High power regenerative laser amplifier

    DOEpatents

    Miller, John L.; Hackel, Lloyd A.; Dane, Clifford B.; Zapata, Luis E.

    1994-01-01

    A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse.

  15. Staged regenerative sorption heat pump

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1995-01-01

    A regenerative adsorbent heat pump process and system for cooling and heating a space. A sorbent is confined in a plurality of compressors of which at least four are first stage and at least four are second stage. The first stage operates over a first pressure region and the second stage over a second pressure region which is higher than the first. Sorbate from the first stage enters the second stage. The sorbate loop includes a condenser, expansion valve, evaporator and the compressors. A single sorbate loop can be employed for single-temperature-control such as air conditioning and heating. Two sorbate loops can be used for two-temperature-control as in a refrigerator and freezer. The evaporator temperatures control the freezer and refrigerator temperatures. Alternatively the refrigerator temperature can be cooled by the freezer with one sorbate loop. A heat transfer fluid is circulated in a closed loop which includes a radiator and the compressors. Low temperature heat is exhausted by the radiator. High temperature heat is added to the heat transfer fluid entering the compressors which are desorbing vapor. Heat is transferred from compressors which are sorbing vapor to the heat transfer fluid, and from the heat transfer fluid to the compressors which are desorbing vapor. Each compressor is subjected to the following phases, heating to its highest temperature, cooling down from its highest temperature, cooling to its lowest temperature, and warming up from its lowest temperature. The phases are repeated to complete a cycle and regenerate heat.

  16. A regenerative elastocaloric heat pump

    NASA Astrophysics Data System (ADS)

    Tušek, Jaka; Engelbrecht, Kurt; Eriksen, Dan; Dall'Olio, Stefano; Tušek, Janez; Pryds, Nini

    2016-10-01

    A large fraction of global energy use is for refrigeration and air-conditioning, which could be decarbonized if efficient renewable energy technologies could be found. Vapour-compression technology remains the most widely used system to move heat up the temperature scale after more than 100 years; however, caloric-based technologies (those using the magnetocaloric, electrocaloric, barocaloric or elastocaloric effect) have recently shown a significant potential as alternatives to replace this technology due to high efficiency and the use of green solid-state refrigerants. Here, we report a regenerative elastocaloric heat pump that exhibits a temperature span of 15.3 K on the water side with a corresponding specific heating power up to 800 W kg-1 and maximum COP (coefficient-of-performance) values of up to 7. The efficiency and specific heating power of this device exceeds those of other devices based on caloric effects. These results open up the possibility of using the elastocaloric effect in various cooling and heat-pumping applications.

  17. Regenerative medicine for neurological disorders.

    PubMed

    Park, Dong-Hyuk; Eve, David J; Chung, Yong-Gu; Sanberg, Paul R

    2010-03-16

    The annual meeting of the American Society for Neural Therapy and Repair (ASNTR) has always introduced us to top-notch and up-to-date approaches for regenerative medicine related to neuroscience, ranging from stem cell-based therapy to novel drugs. The 16th ASNTR meeting focused on a variety of different topics, including the unknown pathogenesis or mechanisms of specific neurodegenerative diseases, stem cell biology, and development of novel alternative medicines or devices. Newly developed stem cells, such as amniotic epithelial stem cells and induced pluripotent stem cells, as well as well-known traditional stem cells, such as neural, embryonic, bone marrow mesenchymal, and human umbilical cord blood-derived stem cells, were reported. A number of commercialized stem cells were also covered at this meeting. Fetal neural tissues, such as ventral mesencephalon, striatum, and Schwann cells, were investigated for neurodegenerative diseases or spinal cord injury. A number of studies focused on novel methods for drug monitoring or graft tracking, and combination therapy with stem cells and medicine, such as cytokines or trophic factors. Finally, the National Institutes of Health guidelines for human stem cell research, clinical trials of commercialized stem cells without larger animal testing, and prohibition of medical tourism were big controversial issues that led to heated discussion.

  18. Regenerative rotary displacer Stirling engine

    SciTech Connect

    Isshiki, Naotsugu; Watanabe, Hiroichi; Raggi, L.; Isshiki, Seita; Hirata, Koichi

    1996-12-31

    A few rotary displacer Stirling engines in which the displacer has one gas pocket space at one side and rotates in a main enclosed cylinder, which is heated from one side and cooled from opposite side without any regenerator, have been studied for some time by the authors. The authors tried to improve this engine by equipping it with a regenerator, because without a regenerator, pressure oscillation and efficiency are too small. Here, several types of regenerative rotary displacer piston Stirling engines are proposed. One is the contra-rotating tandem two disc type displacer engine using axial heat conduction through side walls or by heat pipes and another is a single disc type with circulating fluid regenerator or heat pipes. Stirling engines of this new rotary displacer type are thought to attain high speed. Here, experimental results of the original rotary displacer Stirling engine without a regenerator, and one contra-rotating tandem displacer engine with side wall regenerator by axial heat conduction are reported accompanied with a discussion of the results.

  19. Clinical imaging in regenerative medicine

    PubMed Central

    Naumova, Anna V; Modo, Michel; Moore, Anna; Murry, Charles E; Frank, Joseph A

    2014-01-01

    In regenerative medicine, clinical imaging is indispensable for characterizing damaged tissue and for measuring the safety and efficacy of therapy. However, the ability to track the fate and function of transplanted cells with current technologies is limited. Exogenous contrast labels such as nanoparticles give a strong signal in the short term but are unreliable long term. Genetically encoded labels are good both short- and long-term in animals, but in the human setting they raise regulatory issues related to the safety of genomic integration and potential immunogenicity of reporter proteins. Imaging studies in brain, heart and islets share a common set of challenges, including developing novel labeling approaches to improve detection thresholds and early delineation of toxicity and function. Key areas for future research include addressing safety concerns associated with genetic labels and developing methods to follow cell survival, differentiation and integration with host tissue. Imaging may bridge the gap between cell therapies and health outcomes by elucidating mechanisms of action through longitudinal monitoring. PMID:25093889

  20. Regenerative fuel cell engineering - FY99

    SciTech Connect

    Michael A. Inbody; Rodney L. Borup; James C. Hedstrom; Jose Tafoya; Byron Morton; Lois Zook; Nicholas E. Vanderborgh

    2000-01-01

    The authors report the work conducted by the ESA-EPE Fuel Cell Engineering Team at Los Alamos National Laboratory during FY99 on regenerative fuel cell system engineering. The work was focused on the evaluation of regenerative fuel cell system components obtained through the RAFCO program. These components included a 5 kW PEM electrolyzer, a two-cell regenerative fuel cell stack, and samples of the electrolyzer membrane, anode, and cathode. The samples of the electrolyzer membrane, anode, and cathode were analyzed to determine their structure and operating characteristics. Tests were conducted on the two-cell regenerative fuel cell stack to characterize its operation as an electrolyzer and as a fuel cell. The 5 kW PEM electrolyzer was tested in the Regenerative Fuel Cell System Test Facility. These tests served to characterize the operation of the electrolyzer and, also, to verify the operation of the newly completed test facility. Future directions for this work in regenerative fuel cell systems are discussed.

  1. Regenerative Medicine Applications in Wound Care.

    PubMed

    Ali Nilforoushzadeh, Mohammad; Mollapour Sisakht, Mahsa; Marcus Seifalian, Alexander; Amir Amirkhani, Mohammad; Reza Banafsheh, Hamid; Verdi, Javad; Sharifzad, Farzaneh; Taghiabadi, Ehsan

    2017-09-29

    During the last two decades, a number of studies have been published on different aspects of regenerative medicine in the field of dermatology. The following article aims at integrating all available information about regenerative dermatology, from the past to the present. In addition, we focused on most well-known application of regenerative medicine in dermatology field, wound healing, especially for burns and non-healing wounds based on available skin replacement in market. The present review focuses on providing an overview on available products in market and on-going clinical trials. These are valuable to get the picture of latest trends and also helpful for clinicians. In future, regenerative dermatology may encompass more effective and time-saving therapies for treating skin injuries and diseases. However, more clinical trials are required to establish standardized protocols and ascertain the safety, long-term effects, and efficacy of the novel therapeutic methods in regenerative dermatology. Despite several improvements in this field, extensive research is required for performing successful and precise clinical trials in future. Further improvements would enable the researchers to develop new products in this field. In this review, we have discussed the most recent breakthroughs in the field of regenerative dermatology. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  2. Current overview on challenges in regenerative endodontics

    PubMed Central

    Bansal, Ramta; Jain, Aditya; Mittal, Sunandan

    2015-01-01

    Introduction: Regenerative endodontics provides hope of converting the non-vital tooth into vital once again. It focuses on substituting traumatized and pathological pulp with functional pulp tissue. Current regenerative procedures successfully produce root development but still fail to re-establish real pulp tissue and give unpredictable results. There are several drawbacks that need to be addressed to improve the quality and efficiency of the treatment. Aim: The aim of this review article is to discuss major priorities that ought to be dealt before applications of regenerative endodontics flourish the clinical practice. Materials and Methods: A web-based research on MEDLINE was done using filter terms Review, published in the last 10 years and Dental journals. Keywords used for research were “regenerative endodontics,” “dental stem cells,” “growth factor regeneration,” “scaffolds,” and “challenges in regeneration.” This review article screened about 150 articles and then the relevant information was compiled. Results: Inspite of the impressive growth in regenerative endodontic field, there are certain loopholes in the existing treatment protocols that might sometimes result in undesired and unpredictable outcomes. Conclusion: Considerable research and development efforts are required to improve and update existing regenerative endodontic strategies to make it an effective, safe, and biological mode to save teeth. PMID:25657518

  3. Current overview on challenges in regenerative endodontics.

    PubMed

    Bansal, Ramta; Jain, Aditya; Mittal, Sunandan

    2015-01-01

    Regenerative endodontics provides hope of converting the non-vital tooth into vital once again. It focuses on substituting traumatized and pathological pulp with functional pulp tissue. Current regenerative procedures successfully produce root development but still fail to re-establish real pulp tissue and give unpredictable results. There are several drawbacks that need to be addressed to improve the quality and efficiency of the treatment. The aim of this review article is to discuss major priorities that ought to be dealt before applications of regenerative endodontics flourish the clinical practice. A web-based research on MEDLINE was done using filter terms Review, published in the last 10 years and Dental journals. Keywords used for research were "regenerative endodontics," "dental stem cells," "growth factor regeneration," "scaffolds," and "challenges in regeneration." This review article screened about 150 articles and then the relevant information was compiled. Inspite of the impressive growth in regenerative endodontic field, there are certain loopholes in the existing treatment protocols that might sometimes result in undesired and unpredictable outcomes. Considerable research and development efforts are required to improve and update existing regenerative endodontic strategies to make it an effective, safe, and biological mode to save teeth.

  4. Electrolytic cell stack with molten electrolyte migration control

    DOEpatents

    Kunz, H.R.; Guthrie, R.J.; Katz, M.

    1987-03-17

    An electrolytic cell stack includes inactive electrolyte reservoirs at the upper and lower end portions thereof. The reservoirs are separated from the stack of the complete cells by impermeable, electrically conductive separators. Reservoirs at the negative end are initially low in electrolyte and the reservoirs at the positive end are high in electrolyte fill. During stack operation electrolyte migration from the positive to the negative end will be offset by the inactive reservoir capacity. In combination with the inactive reservoirs, a sealing member of high porosity and low electrolyte retention is employed to limit the electrolyte migration rate. 5 figs.

  5. Electrolytic cell stack with molten electrolyte migration control

    DOEpatents

    Kunz, H. Russell; Guthrie, Robin J.; Katz, Murray

    1988-08-02

    An electrolytic cell stack includes inactive electrolyte reservoirs at the upper and lower end portions thereof. The reservoirs are separated from the stack of the complete cells by impermeable, electrically conductive separators. Reservoirs at the negative end are initially low in electrolyte and the reservoirs at the positive end are high in electrolyte fill. During stack operation electrolyte migration from the positive to the negative end will be offset by the inactive reservoir capacity. In combination with the inactive reservoirs, a sealing member of high porosity and low electrolyte retention is employed to limit the electrolyte migration rate.

  6. Electrochemically stable electrolytes

    DOEpatents

    Angell, C.A.; Zhang, S.S.; Xu, K.

    1999-01-05

    This invention relates generally to inorganic ionic liquids which function as electrolytes and do not crystallize at ambient temperature. More specifically, this invention is directed to quasi-salt inorganic ionic liquids which comprise the reaction product of a strong Lewis acid with an inorganic halide-donating molecule. This invention is further directed to quasi-salt inorganic ionic liquid mixtures which comprise combinations of electrolyte additives and quasi-salt inorganic ionic liquids. These quasi-salt inorganic ionic liquid mixtures are useful electrolytes. 16 figs.

  7. Electrochemically stable electrolytes

    DOEpatents

    Angell, Charles Austen; Zhang, Sheng-Shui; Xu, Kang

    1999-01-01

    This invention relates generally to inorganic ionic liquids which function as electrolytes and do not crystallize at ambient temperature. More specifically, this invention is directed to quasi-salt inorganic ionic liquids which comprise the reaction product of a strong Lewis acid with an inorganic halide-donating molecule. This invention is further directed to quasi-salt inorganic ionic liquid mixtures which comprise combinations of electrolyte additives and quasi-salt inorganic ionic liquids. These quasi-salt inorganic ionic liquid mixtures are useful electrolytes.

  8. Integrated Modular Propulsion and Regenerative Electro-energy Storage System (IMPRESS) for small satellites

    SciTech Connect

    Mitlitsky, F.; de Groot, W.; Butler, L.; McElroy, J.

    1996-09-01

    The IMPRESS is a significant advancement in space system technology as it is able to operate alternately as a fuel cell to produce electrical power from stored hydrogen and oxygen and as a water electrolyzer using electrical power to produce hydrogen and oxygen from stored water. The electrolysis of a controllable fraction of stored water can provide high Isp rocket propellants on demand. The heart of the IMPRESS is the Unitized Regenerative Fuel Cell (URFC), which produces power and electrolytically regenerates its reactants using a single stack of reversible cells. This integrated approach has several significant advantages over separate (battery) power and propulsion systems.

  9. Alkaline water electrolysis technology for Space Station regenerative fuel cell energy storage

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Hoberecht, M. A.; Le, M.

    1986-01-01

    The regenerative fuel cell system (RFCS), designed for application to the Space Station energy storage system, is based on state-of-the-art alkaline electrolyte technology and incorporates a dedicated fuel cell system (FCS) and water electrolysis subsystem (WES). In the present study, emphasis is placed on the WES portion of the RFCS. To ensure RFCS availability for the Space Station, the RFCS Space Station Prototype design was undertaken which included a 46-cell 0.93 cu m static feed water electrolysis module and three integrated mechanical components.

  10. Alkaline water electrolysis technology for Space Station regenerative fuel cell energy storage

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Hoberecht, M. A.; Le, M.

    1986-01-01

    The regenerative fuel cell system (RFCS), designed for application to the Space Station energy storage system, is based on state-of-the-art alkaline electrolyte technology and incorporates a dedicated fuel cell system (FCS) and water electrolysis subsystem (WES). In the present study, emphasis is placed on the WES portion of the RFCS. To ensure RFCS availability for the Space Station, the RFCS Space Station Prototype design was undertaken which included a 46-cell 0.93 cu m static feed water electrolysis module and three integrated mechanical components.

  11. Electrolytic oxidation of anthracite

    USGS Publications Warehouse

    Senftle, F.E.; Patton, K.M.; Heard, I.

    1981-01-01

    An anthracite slurry can be oxidized only with difficulty by electrolytic methods in which aqueous electrolytes are used if the slurry is confined to the region of the anode by a porous pot or diaphragm. However, it can be easily oxidized if the anthracite itself is used as the anode. No porous pot or diaphragm is needed. Oxidative consumption of the coal to alkali-soluble compounds is found to proceed preferentially at the edges of the aromatic planes. An oxidation model is proposed in which the chief oxidants are molecular and radical species formed by the electrolytic decomposition of water at the coal surface-electrolyte interface. The oxidation reactions proposed account for the opening of the aromatic rings and the subsequent formation of carboxylic acids. The model also explains the observed anisotropic oxidation and the need for the porous pot or diaphragm used in previous studies of the oxidation of coal slurries. ?? 1981.

  12. Analysis of cell performance and thermal regeneration of a lithium-tin cell having an immobilized fused-salt electrolyte

    NASA Technical Reports Server (NTRS)

    Cairns, E. J.; Shimotake, H.

    1969-01-01

    Cell performance and thermal regeneration of a thermally regenerative cell uses lithium and tin and a fused-salt electrolyte. The emf of the Li-Sn cell, as a function of cathode-alloy composition, is shown to resemble that of the Na-Bi cell.

  13. Solid electrolyte cell

    NASA Technical Reports Server (NTRS)

    Richter, R. (Inventor)

    1982-01-01

    A solid electrolyte cell including a body of solid ionized gas-conductive electrolyte having mutually spaced surfaces and on which is deposited a multiplicity of mutually spaced electrodes is described. Strips and of bare substances are interposed between electrodes, so that currents of ionic gas may be established between the electrodes via the bare strips, whereby electrical resistance for the cells is lowered and the gas conductivity is enhanced.

  14. Performance of composite electrolyte SOFCs

    SciTech Connect

    Khandkar, A.C.; Elangovan, S.; Milliken, C.; Guruswamy, S.

    1994-12-31

    In an effort to minimize the ohmic losses in solid oxide fuel cells (SOFC), especially at lower operating temperatures around 800 C, an alternate electrolyte material such as ceria is often adopted. However, ceria based electrolytes develop mixed conduction, which lowers faradaic efficiency. To alleviate this effect, ceria electrolytes were coated with a thin layer zirconia using high temperature magnetron sputter deposition. This paper discusses the characterization of electrolytes and performance of single cells fabricated from these composite electrolytes.

  15. Regenerative medicine: Current therapies and future directions

    PubMed Central

    Mao, Angelo S.; Mooney, David J.

    2015-01-01

    Organ and tissue loss through disease and injury motivate the development of therapies that can regenerate tissues and decrease reliance on transplantations. Regenerative medicine, an interdisciplinary field that applies engineering and life science principles to promote regeneration, can potentially restore diseased and injured tissues and whole organs. Since the inception of the field several decades ago, a number of regenerative medicine therapies, including those designed for wound healing and orthopedics applications, have received Food and Drug Administration (FDA) approval and are now commercially available. These therapies and other regenerative medicine approaches currently being studied in preclinical and clinical settings will be covered in this review. Specifically, developments in fabricating sophisticated grafts and tissue mimics and technologies for integrating grafts with host vasculature will be discussed. Enhancing the intrinsic regenerative capacity of the host by altering its environment, whether with cell injections or immune modulation, will be addressed, as well as methods for exploiting recently developed cell sources. Finally, we propose directions for current and future regenerative medicine therapies. PMID:26598661

  16. Regenerative Medicine and Stem Cells in Dermatology.

    PubMed

    Moioli, Eduardo K; Bolotin, Diana; Alam, Murad

    2017-05-01

    Clinically relevant regenerative medicine is still in its early stages of development. Difficulties in regenerating large-scale and complex structures, the lack of safety data, and the paucity of clinical trials have slowed the process of technological advance. To familiarize the clinician with techniques available in the laboratory and experimental approaches being tested clinically. In addition, a layout is discussed for how dermatologists can lead the way in bringing regenerative medicine to clinical reality. This article reviews the relevant literature on regenerative medicine for dermatological applications and discusses findings and techniques in a clinically relevant context. Multiple cell-free and cell-based approaches for regenerating dermatologic tissues have been reported in the basic science and clinical literature. These are reviewed in the order of complexity. Incremental steps are needed to apply the principles of regenerative medicine to simple medical problems first. Such a stepwise approach would commence, for example, with creation of single-function tissues that could fill soft-tissue defects and proceed to the development of fully functional skin grafts. Likewise, cell-free approaches can build the foundation for the more technically demanding cell-based strategies that are likely necessary for achieving the ultimate goal of regenerative dermatology.

  17. Regenerative principles enrich cardiac rehabilitation practice.

    PubMed

    Behfar, Atta; Terzic, Andre; Perez-Terzic, Carmen M

    2014-11-01

    Cardiovascular morbidity imposes a high degree of disability and mortality, with limited therapeutic options available in end-stage disease. Integral to standard of care, cardiac rehabilitation aims on improving quality-of-life and prolonging survival. The recent advent of regenerative technologies paves the way for a transformative era in rehabilitation medicine whereby, beyond controlling risk factors and disease progression, the prospect of curative solutions is increasingly tangible. To date, the spectrum of clinical experience in cardiac regenerative medicine relies on stem cell-based therapies delivered to the diseased myocardium either acutely/subacutely, after a coronary event, or in the setting of chronic heart failure. Application of autologous/allogeneic stem cell platforms has established safety and feasibility, with encouraging signals of efficacy. Newer protocols aim to purify cell populations in an attempt to eliminate nonregenerative and enrich for regenerative cell types before use. Most advanced technologies have been developed to isolate resident cell populations directly from the heart or, alternatively, condition cells from noncardiac sources to attain a disease-targeted lineage-specified phenotype for optimized outcome. Because a multiplicity of cell-based technologies has undergone phase I/II evaluation, pivotal trials are currently underway in larger patient populations. Translation of regenerative principles into clinical practice will increasingly involve rehabilitation providers across the continuum of patient care. Regenerative rehabilitation is thus an emerging multidisciplinary field, full of opportunities and ready to be explored.

  18. Functional imaging for regenerative medicine.

    PubMed

    Leahy, Martin; Thompson, Kerry; Zafar, Haroon; Alexandrov, Sergey; Foley, Mark; O'Flatharta, Cathal; Dockery, Peter

    2016-04-19

    In vivo imaging is a platform technology with the power to put function in its natural structural context. With the drive to translate stem cell therapies into pre-clinical and clinical trials, early selection of the right imaging techniques is paramount to success. There are many instances in regenerative medicine where the biological, biochemical, and biomechanical mechanisms behind the proposed function of stem cell therapies can be elucidated by appropriate imaging. Imaging techniques can be divided according to whether labels are used and as to whether the imaging can be done in vivo. In vivo human imaging places additional restrictions on the imaging tools that can be used. Microscopies and nanoscopies, especially those requiring fluorescent markers, have made an extraordinary impact on discovery at the molecular and cellular level, but due to their very limited ability to focus in the scattering tissues encountered for in vivo applications they are largely confined to superficial imaging applications in research laboratories. Nanoscopy, which has tremendous benefits in resolution, is limited to the near-field (e.g. near-field scanning optical microscope (NSNOM)) or to very high light intensity (e.g. stimulated emission depletion (STED)) or to slow stochastic events (photo-activated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM)). In all cases, nanoscopy is limited to very superficial applications. Imaging depth may be increased using multiphoton or coherence gating tricks. Scattering dominates the limitation on imaging depth in most tissues and this can be mitigated by the application of optical clearing techniques that can impose mild (e.g. topical application of glycerol) or severe (e.g. CLARITY) changes to the tissue to be imaged. Progression of therapies through to clinical trials requires some thought as to the imaging and sensing modalities that should be used. Smoother progression is facilitated by the use of

  19. Regenerative fuel cell energy storage system for a low earth orbit space station

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Garow, J.; Michaels, K. B.

    1988-01-01

    A study was conducted to define characteristics of a Regenerative Fuel Cell System (RFCS) for low earth orbit Space Station missions. The RFCS's were defined and characterized based on both an alkaline electrolyte fuel cell integrated with an alkaline electrolyte water electrolyzer and an alkaline electrolyte fuel cell integrated with an acid solid polymer electrolyte (SPE) water electrolyzer. The study defined the operating characteristics of the systems including system weight, volume, and efficiency. A maintenance philosophy was defined and the implications of system reliability requirements and modularization were determined. Finally, an Engineering Model System was defined and a program to develop and demonstrate the EMS and pacing technology items that should be developed in parallel with the EMS were identified. The specific weight of an optimized RFCS operating at 140 F was defined as a function of system efficiency for a range of module sizes. An EMS operating at a nominal temperature of 180 F and capable of delivery of 10 kW at an overall efficiency of 55.4 percent is described. A program to develop the EMS is described including a technology development effort for pacing technology items.

  20. Regenerative fuel cell energy storage system for a low earth orbit space station

    NASA Astrophysics Data System (ADS)

    Martin, R. E.; Garow, J.; Michaels, K. B.

    1988-04-01

    A study was conducted to define characteristics of a Regenerative Fuel Cell System (RFCS) for low earth orbit Space Station missions. The RFCS's were defined and characterized based on both an alkaline electrolyte fuel cell integrated with an alkaline electrolyte water electrolyzer and an alkaline electrolyte fuel cell integrated with an acid solid polymer electrolyte (SPE) water electrolyzer. The study defined the operating characteristics of the systems including system weight, volume, and efficiency. A maintenance philosophy was defined and the implications of system reliability requirements and modularization were determined. Finally, an Engineering Model System was defined and a program to develop and demonstrate the EMS and pacing technology items that should be developed in parallel with the EMS were identified. The specific weight of an optimized RFCS operating at 140 F was defined as a function of system efficiency for a range of module sizes. An EMS operating at a nominal temperature of 180 F and capable of delivery of 10 kW at an overall efficiency of 55.4 percent is described. A program to develop the EMS is described including a technology development effort for pacing technology items.

  1. Electrolyte-induced inversion layer Schottky junction solar cells.

    PubMed

    Wadhwa, Pooja; Seol, Gyungseon; Petterson, Maureen K; Guo, Jing; Rinzler, Andrew G

    2011-06-08

    A new type of crystalline silicon solar cell is described. Superficially similar to a photoelectrochemical cell a liquid electrolyte creates a depletion (inversion) layer in an n-type silicon wafer, however no regenerative redox couple is present to ferry charge between the silicon and a counter electrode. Instead holes trapped in the electrolyte-induced inversion layer diffuse along the layer until they come to widely spaced grid lines, where they are extracted. The grid lines consist of a single-walled carbon nanotube film etched to cover only a fraction of the n-Si surface. Modeling and simulation shows the inversion layer to be a natural consequence of the device electrostatics. With electronic gating, recently demonstrated to boost the efficiency in related devices, the cell achieves a power conversion efficiency of 12%, exceeding the efficiency of dye sensitized solar cells.

  2. Therapeutic potential of nanoceria in regenerative medicine

    SciTech Connect

    Das, Soumen; Chigurupati, Srinivasulu; Dowding, Janet; Munusamy, Prabhakaran; Baer, Donald R.; McGinnis, James F.; Mattson, Mark P.; Self, William; Seal, Sudipta

    2014-11-01

    Tissue engineering and regenerative medicine aim to achieve functional restoration of tissue or cells damaged through disease, aging or trauma. Advancement of tissue engineering requires innovation in the field of 3D scaffolding, and functionalization with bioactive molecules. Nanotechnology offers advanced materials with patterned nano-morphologies for cell growth and different molecular substrates which can support cell survival and functions. Cerium oxide nanoparticles (nanoceria) can control intracellular as well as extracellular reactive oxygen and nitrogen species. Recent findings suggest that nanoceria can enhance long-term cell survival, enable cell migration and proliferation, and promote stem cell differentiation. Moreover, the self-regenerative property of nanoceria permits a small dose to remain catalytically active for extended time. This review summarizes the possibilities and applications of nanoceria in the field of tissue engineering and regenerative medicine.

  3. Combined hydraulic and regenerative braking system

    DOEpatents

    Venkataperumal, R.R.; Mericle, G.E.

    1979-08-09

    A combined hydraulic and regenerative braking system and method for an electric vehicle is disclosed. The braking system is responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially regenerative at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.

  4. Cardiovascular Regenerative Technologies: Update and Future Outlook

    PubMed Central

    Mallone, Anna; Weber, Benedikt; Hoerstrup, Simon P.

    2016-01-01

    In the effort of improving treatment for cardiovascular disease (CVD), scientists struggle with the lack of the regenerative capacities of finally differentiated cardiovascular tissues. In this context, the advancements in regenerative medicine contributed to the development of cell-based therapies as well as macro- and micro-scale tissue-engineering technologies. The current experimental approaches focus on different regenerative strategies including a broad spectrum of techniques such as paracrine-based stimulation of autologous cardiac stem cells, mesenchymal cell injections, 3D microtissue culture techniques and vascular tissue-engineering methods. These potential next-generation strategies are leading the way to a revolution in addressing CVD, and numerous studies are now undertaken to assess their therapeutic value. With this review, we provide an update on the current research directions, on their major challenges, limitations, and achievements. PMID:27721705

  5. Combined hydraulic and regenerative braking system

    SciTech Connect

    Venkataperumal, Rama R.; Mericle, Gerald E.

    1981-06-02

    A combined hydraulic and regenerative braking system and method for an electric vehicle, with the braking system being responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially regenerative at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.

  6. Regenerative potential of immature permanent teeth with necrotic pulps after different regenerative protocols.

    PubMed

    Nagy, Mohamed M; Tawfik, Hosam E; Hashem, Ahmed Abdel Rahman; Abu-Seida, Ashraf M

    2014-02-01

    Regenerative endodontics is a promising alternative treatment for immature teeth with necrotic pulps. The present study was performed to assess the regenerative potential of young permanent immature teeth with necrotic pulp after the following treatment protocols: (1) a mineral trioxide aggregate (MTA) apical plug, (2) the regenerative endodontic protocol (blood clot scaffold), and (3) the regenerative endodontic protocol with a blood clot and an injectable scaffold impregnated with basic fibroblast growth factor. Immature necrotic permanent maxillary central incisors (n = 36) of patients 9-13 years old were divided into 3 groups according to the treatment protocol: the MTA group (MTA apical plug), the REG group (regenerative endodontic protocol [blood clot]), and the FGF group (regenerative endodontic protocol [blood clot + injectable scaffold]). Follow-up was done up to 18 months. Standardized radiographs were digitally evaluated for an increase in root length and thickness, a decrease in the apical diameter, and a change in periapical bone density. After a follow-up period of 18 months, most of the cases showed radiographic evidence of periapical healing. Groups 2 and 3 showed a progressive increase in root length and width and a decrease in apical diameter. The regenerative endodontic procedure allowed the continued development of roots in teeth with necrotic pulps. The use of artificial hydrogel scaffold and basic fibroblast growth factor was not essential for repair. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Regenerative therapy: a periodontal-endodontic perspective.

    PubMed

    Kinaia, Bassam Michael; Chogle, Sami M A; Kinaia, Atheel M; Goodis, Harold E

    2012-07-01

    Periodontal and endodontic diseases are inflammatory responses leading to periodontal and pulpal tissue loss. Regenerative therapies aim to restore the lost structures to vitality and function. Various materials and treatments methods have been used such as bone grafts, guided tissue regeneration, enamel matrix derivatives, growth and differentiation factors, and stem cells. Although the current materials and methods demonstrated adequate clinical results, true and complete biological tissue regeneration is not yet attainable. The current article reviews chronologically the materials and methods used in periodontal and endodontic regeneration highlighting their clinical success and shortcomings, and discussing future directions in regenerative therapy.

  8. WIDE BAND REGENERATIVE FREQUENCY DIVIDER AND MULTIPLIER

    DOEpatents

    Laine, E.F.

    1959-11-17

    A regenerative frequency divider and multiplier having wide band input characteristics is presented. The circuit produces output oscillations having frequencies related by a fixed ratio to input oscillations over a wide band of frequencies. In accomplishing this end, the divider-multiplier includes a wide band input circuit coupled by mixer means to a wide band output circuit having a pass band related by a fixed ratio to that of the input circuit. A regenerative feedback circuit derives a fixed frequency ratio feedback signal from the output circuit and applies same to the mixer means in proper phase relation to sustain fixed frequency ratio oscillations in the output circuit.

  9. Global strategic partnerships in regenerative medicine.

    PubMed

    French, Anna; Suh, Jane Y; Suh, Carol Y; Rubin, Lee; Barker, Richard; Bure, Kim; Reeve, Brock; Brindley, David A

    2014-09-01

    The approach to research and development in biomedical science is changing. Increasingly, academia and industry seek to collaborate, and share resources and expertise, by establishing partnerships. Here, we explore the co-development partnership landscape in the field of regenerative medicine, focusing on agreements involving one or more private entities. A majority of the largest biopharmaceutical companies have announced strategic partnerships with a specific regenerative medicine focus, signifying the growth and widening appeal of this emerging sector. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Improved Regenerative Sorbent-Compressor Refrigerator

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1992-01-01

    Conceptual regenerative sorbent-compressor refrigerator attains regeneration efficiency and, therefore, overall power efficiency and performance greater than conventional refrigerators. Includes two fluid loops. In one, CH2FCF3 (R134a) ciculates by physical adsorption and desorption in four activated-charcoal sorption compressors. In other, liquid or gas coolant circulated by pump. Wave of regenerative heating and cooling propagates cyclically like peristatic wave among sorption compressors and associated heat exchangers. Powered by electricity, oil, gas, solar heat, or waste heat. Used as air conditioners, refrigerators, and heat pumps in industrial, home, and automotive applications.

  11. Lightweight pressure vessels and unitized regenerative fuel cells

    SciTech Connect

    Mitlitsky, F.; Myers, B.; Weisberg, A.H.

    1996-12-31

    High specific energy (>400 Wh/kg) energy storage systems have been designed using lightweight pressure vessels in conjunction with unitized regenerative fuel cells (URFCs). URFCs produce power and electrolytically regenerate their reactants using a single stack of reversible cells. Although a rechargeable energy storage system with such high specific energy has not yet been fabricated, we have made progress towards this goal. A primary fuel cell (FC) test rig with a single cell (0.05 ft{sup 2} active area) has been modified and operated reversibly as a URFC. This URFC uses bifunctional electrodes (oxidation and reduction electrodes reverse roles when switching from charge to discharge, as with a rechargeable battery) and cathode feed electrolysis (water is fed from the oxygen side of the cell). Lightweight pressure vessels with state-of-the-art performance factors (burst pressure * internal volume/tank weight = Pb V/W) have been designed and fabricated. These vessels provide a lightweight means of storing reactant gases required for fuel cells (FCs) or URFCs. The vessels use lightweight bladder liners that act as inflatable mandrels for composite overwrap and provide the permeation barrier for gas storage. The bladders are fabricated using materials that are compatible with humidified gases which may be created by the electrolysis of water and are compatible with elevated temperatures that occur during fast fills.

  12. Gel electrolytes and electrodes

    DOEpatents

    Fleischmann, Sven; Bunte, Christine; Mikhaylik, Yuriy V.; Viner, Veronika G.

    2017-09-05

    Gel electrolytes, especially gel electrolytes for electrochemical cells, are generally described. In some embodiments, the gel electrolyte layers comprise components a) to c). Component a) may be at least one layer of at least one polymer comprising polymerized units of: a1) at least one monomer containing an ethylenically unsaturated unit and an amido group and a2) at least one crosslinker. Component b) may be at least one conducting salt and component c) may be at least one solvent. Electrodes may comprise the components a), d) and e), wherein component a) may be at least one layer of at least one polymer as described herein. Component d) may be at least one electroactive layer and component e) may be at least one ceramic layer. Furthermore, electrochemical cells comprising component a) which may be at least one layer of at least one polymer as described herein, are also provided.

  13. Expanding horizons of cellular plasticity in regenerative medicine.

    PubMed

    Sen, Chandan K

    2015-10-01

    This Guest Editorial introduces the Regenerative Medicine Theme Issue, which provides critical insight into the unfolding frontier of regenerative medicine. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  14. Seebeck effect in electrolytes.

    PubMed

    Chikina, I; Shikin, V; Varlamov, A A

    2012-07-01

    We study Seebeck effect in liquid electrolytes, starting from its simple neutral analog--thermodiffusion (so-called Ludwig-Soret or Soret effect). It is observed that when two or more subsystems of mobile particles are subjected to the temperature gradient, various types of them respond to it differently. In the case when these fractions, with different mobility parameters (Soret coefficients), are oppositely charged (a case typical for electrolytes), the nonhomogeneous internal electric field is generated. The latter field prevents these fractions from space separation and determines the intensity of the appearing Seebeck effect.

  15. Mesenchymal stem cells, aging and regenerative medicine

    PubMed Central

    Raggi, Chiara; Berardi, Anna C.

    2012-01-01

    Summary Tissue maintenance and regeneration is dependent on stem cells and increasing evidence has shown to decline with age. Stem cell based-aging is thought to influence therapeutic efficacy. Mesenchymal stromal cells (MSCs) are involved in tissue regeneration. Here, we discuss the effects of age-related changes on MSC properties considering their possible use in research or regenerative medicine. PMID:23738303

  16. Regenerative Studies: College Community and Community College.

    ERIC Educational Resources Information Center

    Woltz, Mary G.

    This case study applies principles derived from the Center for Regenerative Studies (CRS) to a community college in North Carolina. CRS, on the campus of California State Polytechnic Institute (California), is dedicated to the education, demonstration, and research of degenerative systems in the areas of shelter, food production, energy, water and…

  17. Regenerative nanomedicine: current perspectives and future directions

    PubMed Central

    Chaudhury, Koel; Kumar, Vishu; Kandasamy, Jayaprakash; RoyChoudhury, Sourav

    2014-01-01

    Nanotechnology has considerably accelerated the growth of regenerative medicine in recent years. Application of nanotechnology in regenerative medicine has revolutionized the designing of grafts and scaffolds which has resulted in new grafts/scaffold systems having significantly enhanced cellular and tissue regenerative properties. Since the cell–cell and cell-matrix interaction in biological systems takes place at the nanoscale level, the application of nanotechnology gives an edge in modifying the cellular function and/or matrix function in a more desired way to mimic the native tissue/organ. In this review, we focus on the nanotechnology-based recent advances and trends in regenerative medicine and discussed under individual organ systems including bone, cartilage, nerve, skin, teeth, myocardium, liver and eye. Recent studies that are related to the design of various types of nanostructured scaffolds and incorporation of nanomaterials into the matrices are reported. We have also documented reports where these materials and matrices have been compared for their better biocompatibility and efficacy in supporting the damaged tissue. In addition to the recent developments, future directions and possible challenges in translating the findings from bench to bedside are outlined. PMID:25214780

  18. Applications of regenerative medicine in organ transplantation

    PubMed Central

    Jain, Aditya; Bansal, Ramta

    2015-01-01

    A worldwide shortage of organs for clinical implantation establishes the need to bring forward and test new technologies that will help in solving the problem. The concepts of regenerative medicine hold the potential for augmenting organ function or repairing damaged organ or allowing regeneration of deteriorated organs and tissue. Researchers are exploring possible regenerative medicine applications in organ transplantation so that coming together of the two fields can benefit each other. The present review discusses the strategies that are being implemented to regenerate or bio-engineer human organs for clinical purposes. It also highlights the limitations of the regenerative medicine that needs to be addressed to explore full potential of the field. A web-based research on MEDLINE was done using keywords “regenerative medicine,” “tissue-engineering,” “bio-engineered organs,” “decellularized scaffold” and “three-dimensional printing.” This review screened about 170 articles to get the desired knowledge update. PMID:26229352

  19. Regenerative medicine: does Erythropoietin have a role?

    PubMed

    Buemi, Michele; Lacquaniti, Antonio; Maricchiolo, Giulia; Bolignano, Davide; Campo, Susanna; Cernaro, Valeria; Sturiale, Alessio; Grasso, Giovanni; Buemi, Antoine; Allegra, Alessandro; Donato, Valentina; Genovese, Lucrezia

    2009-01-01

    Regenerative Medicine, a recent new medical domain, aims to develop new therapies through the stimulation of natural regenerative processes also in human beings. In this field, Erythropoietin (EPO) represents a significant subject of research. Several studies allow the assertion that EPO, in different concentrations, has protective effects mainly on the central nervous system, cardiovascular system and renal tissue. This action is carried out through one of few regenerative activities of human beings: angiogenesis. This mechanism, which involves endothelial stem cells and VEGF (Vascular Endothelial Growth Factor), has been experimentally demonstrated with Recombinant human erythropoietin (rHuEPO) and Darbepoetin, a long-acting EPO derivate. Furthermore, the demonstration of a cardiac production of EPO in Fugu rubripes and in Zebrafish has led cardiologists to "discover" Erythropoietin, postulating a hypothetical role in treatment of cardiovascular disease for this hormone. This is some of the experimental evidence which demonstrates that EPO can be in reason considered an important element of research of Regenerative Medicine and put in the network of drugs able to regenerate tissues and organs.

  20. Simulations of the LANL regenerative amplifier FEL

    SciTech Connect

    Kesselring, M.; Colson, W.B.; Wong, R.K.; Sheffield, R.L.

    1997-08-01

    The LANL regenerative amplifier FEL is designed to produce an average output power of 1 kW. Simulations study the transverse effects due to guiding by the intense electron beam and feedback. These simulations coupled with experimental measurements can be used to improve future high-power FEL designs.

  1. Regenerative fuel cells for space applications

    NASA Technical Reports Server (NTRS)

    Appleby, A. John

    1987-01-01

    After several years of development of the regenerative fuel cell (RFC) as the electrochemical storage system to be carried by the future space station, the official stance has now been adopted that nickel hydrogen batteries would be a better system choice. RFCs are compared with nickel hydrogen and other battery systems for space platform applications.

  2. Regenerative nanomedicine: current perspectives and future directions.

    PubMed

    Chaudhury, Koel; Kumar, Vishu; Kandasamy, Jayaprakash; RoyChoudhury, Sourav

    2014-01-01

    Nanotechnology has considerably accelerated the growth of regenerative medicine in recent years. Application of nanotechnology in regenerative medicine has revolutionized the designing of grafts and scaffolds which has resulted in new grafts/scaffold systems having significantly enhanced cellular and tissue regenerative properties. Since the cell-cell and cell-matrix interaction in biological systems takes place at the nanoscale level, the application of nanotechnology gives an edge in modifying the cellular function and/or matrix function in a more desired way to mimic the native tissue/organ. In this review, we focus on the nanotechnology-based recent advances and trends in regenerative medicine and discussed under individual organ systems including bone, cartilage, nerve, skin, teeth, myocardium, liver and eye. Recent studies that are related to the design of various types of nanostructured scaffolds and incorporation of nanomaterials into the matrices are reported. We have also documented reports where these materials and matrices have been compared for their better biocompatibility and efficacy in supporting the damaged tissue. In addition to the recent developments, future directions and possible challenges in translating the findings from bench to bedside are outlined.

  3. Stem cells in regenerative medicine: introduction.

    PubMed

    Ilic, Dusko; Polak, Julia M

    2011-01-01

    Considerable amount of information about the potential of stem cell therapy in regenerative medicine is available today. Scientific meetings and publications in specialized journals enable experts in stem cell science and regenerative medicine to follow worldwide cutting-edge research. However, controversial information plaguing the media and the Internet lead patients to believe that stem cells are the long-awaited panacea even though there are little or no stringent factual data available yet. PubMed database systematically searched in the period 4-6 January 2011. Stem cell-based therapy is a future of regenerative medicine. Based on unsubstantial claims fueled by media, patients are frequently seeking advice about the risks and prospects of specific therapeutic regimes from their physicians. Reports in specialized journals written in a scientific vocabulary are difficult to evaluate for many primary-care physicians. Hence, physicians are reluctant to provide advice or endorse treatment options for cell-based therapies. AREAS TIMELY FOR FURTHER DEVELOPMENT: We wish to fill the gap and offer physicians suitable guidance. By giving a comprehensive overview of different types of stem cells and their potential in a simple language, here we are introducing a series of articles written by world-renowned experts on regenerative medicine about the current status and prospects of the field from the point of view of the standard level of patient safety and efficacy for the healthcare industry.

  4. Where is dentistry in regenerative medicine?

    PubMed

    Ricci, John L; Terracio, Louis

    2011-08-01

    Where does dentistry fit into the field of regenerative medicine? Based on the fact that the goal of regenerative medicine is to restore function to damaged organs and tissues, it is apparent that dentistry, which has long embraced the concept of restoring function of damaged teeth, has embraced this goal from the very beginning. In this brief review we present the opinion that if you take as the primary criterion the restoration of tissue and organ function, dentistry has not only been at the forefront of restorative medicine but actually predates it in practice. We illustrate the depth and breadth of dental regenerative medicine using examples of therapies or potential therapies from our laboratories. These begin with an example from a historical area of strength, dental implant design and fabrication, progress to a more high tech bone scaffold fabrication project, and finish with a stem cell-based soft tissue engineering project. In the final analysis we believe that the restorative nature of dentistry will keep it at the forefront of regenerative medicine. © 2011 FDI World Dental Federation.

  5. Batteries using molten salt electrolyte

    DOEpatents

    Guidotti, Ronald A.

    2003-04-08

    An electrolyte system suitable for a molten salt electrolyte battery is described where the electrolyte system is a molten nitrate compound, an organic compound containing dissolved lithium salts, or a 1-ethyl-3-methlyimidazolium salt with a melting temperature between approximately room temperature and approximately 250.degree. C. With a compatible anode and cathode, the electrolyte system is utilized in a battery as a power source suitable for oil/gas borehole applications and in heat sensors.

  6. Improved electrolytes for fuel cells

    SciTech Connect

    Gard, G.L.; Roe, D.K.

    1991-06-01

    Present day fuel cells based upon hydrogen and oxygen have limited performance due to the use of phosphoric acid as an electrolyte. Improved performance is desirable in electrolyte conductivity, electrolyte management, oxygen solubility, and the kinetics of the reduction of oxygen. Attention has turned to fluorosulfonic acids as additives or substitute electrolytes to improve fuel cell performance. The purpose of this project is to synthesize and electrochemically evaluate new fluorosulfonic acids as superior alternatives to phosphoric acid in fuel cells. (VC)

  7. Integrated Solid-Electrolyte Construction

    NASA Technical Reports Server (NTRS)

    Richter, R.

    1982-01-01

    Proposed construction method for electrolytic cells would integrate porous surface electrodes into a block of solid electrolyte. Porous electrodes would facilitate unrestricted gas flow thereby improving cell performance. Electrode wire mesh is embedded at surface of solid electrolyte. Construction would assure high electrode conductance and low resistance to gas flow.

  8. Spin coating of electrolytes

    DOEpatents

    Stetter, Joseph R.; Maclay, G. Jordan

    1989-01-01

    Methods for spin coating electrolytic materials onto substrates are disclosed. More particularly, methods for depositing solid coatings of ion-conducting material onto planar substrates and onto electrodes are disclosed. These spin coating methods are employed to fabricate electrochemical sensors for use in measuring, detecting and quantifying gases and liquids.

  9. Integrated photovoltaic electrolytic cell

    SciTech Connect

    Ohkawa, T.

    1982-10-05

    A photovoltaic-electrolytic unit is provided to produce an electric current from solar energy and utilize the current to produce hydrogen by the electrolysis of water. The unit floats in an aqueous medium so that photoelectric cells are exposed to solar radiation, and electrodes submerged in the medium produce oxygen which is vented and hydrogen which is collected in the unit.

  10. Solid electrolyte structure

    DOEpatents

    Fraioli, Anthony V.

    1984-01-01

    A solid electrolyte structure for fuel cells and other electrochemical devices providing oxygen ion transfer by a multiplicity of exposed internal surfaces made of a composition containing an oxide of a multivalent transition metal and forming small pore-like passages sized to permit oxygen ion transfer while limiting the transfer of oxygen gas.

  11. Gel polymer electrolytes for batteries

    DOEpatents

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

  12. Reference electrode for electrolytic cell

    DOEpatents

    Kessie, R.W.

    1988-07-28

    A reference electrode device is provided for a high temperature electrolytic cell used to electrolytically recover uranium from spent reactor fuel dissolved in an anode pool, the device having a glass tube to enclose the electrode and electrolyte and serve as a conductive membrane with the cell electrolyte, and an outer metal tube about the glass tube to serve as a shield and basket for any glass sections broken by handling of the tube to prevent their contact with the anode pool, the metal tube having perforations to provide access between the bulk of the cell electrolyte and glass membrane. 4 figs.

  13. Electrolytic cell with reference electrode

    DOEpatents

    Kessie, Robert W.

    1989-01-01

    A reference electrode device is provided for a high temperature electrolytic cell used to electrolytically recover uranium from spent reactor fuel dissolved in an anode pool, the device having a glass tube to enclose the electrode and electrolyte and serve as a conductive membrane with the cell electrolyte, and an outer metal tube about the glass tube to serve as a shield and basket for any glass sections broken by handling of the tube to prevent their contact with the anode pool, the metal tube having perforations to provide access between the bulk of the cell electrolyte and glass membrane.

  14. Fluorescent Cell Imaging in Regenerative Medicine

    PubMed Central

    Sapoznik, Etai; Niu, Guoguang; Zhou, Yu; Murphy, Sean V.; Soker, Shay

    2016-01-01

    Fluorescent protein imaging, a promising tool in biological research, incorporates numerous applications that can be of specific use in the field of regenerative medicine. To enhance tissue regeneration efforts, scientists have been developing new ways to monitor tissue development and maturation in vitro and in vivo. To that end, new imaging tools and novel fluorescent proteins have been developed for the purpose of performing deep-tissue high-resolution imaging. These new methods, such as intra-vital microscopy and Förster resonance energy transfer, are providing new insights into cellular behavior, including cell migration, morphology, and phenotypic changes in a dynamic environment. Such applications, combined with multimodal imaging, significantly expand the utility of fluorescent protein imaging in research and clinical applications of regenerative medicine. PMID:27158228

  15. Electrospun Silk Biomaterial Scaffolds for Regenerative Medicine

    PubMed Central

    Zhang, Xiaohui; Reagan, Michaela R; Kaplan, David L.

    2009-01-01

    Electrospinning is a versatile technique that enables the development of nanofiber-based biomaterial scaffolds. Scaffolds can be generated that are useful for tissue engineering and regenerative medicine since they mimic the nanoscale properties of certain fibrous components of the native extracellular matrix in tissues. Silk is a natural protein with excellent biocompatibility, remarkable mechanical properties as well as tailorable degradability. Integrating these protein polymer advantages with electrospinning results in scaffolds with combined biochemical, topographical and mechanical cues with versatility for a range of biomaterial, cell and tissue studies and applications. This review covers research related to electrospinning of silk, including process parameters, post treatment of the spun fibers, functionalization of nanofibers, and the potential applications for these material systems in regenerative medicine. Research challenges and future trends are also discussed. PMID:19643154

  16. [Progress in stem cells and regenerative medicine].

    PubMed

    Wang, Libin; Zhu, He; Hao, Jie; Zhou, Qi

    2015-06-01

    Stem cells have the ability to differentiate into all types of cells in the body and therefore have great application potential in regenerative medicine, in vitro disease modelling and drug screening. In recent years, stem cell technology has made great progress, and induced pluripotent stem cell technology revolutionizes the whole stem cell field. At the same time, stem cell research in our country has also achieved great progress and becomes an indispensable power in the worldwide stem cell research field. This review mainly focuses on the research progress in stem cells and regenerative medicine in our country since the advent of induced pluripotent stem cell technology, including induced pluripotent stem cells, transdifferentiation, haploid stem cells, and new gene editing tools.

  17. Induced pluripotent stem cells for regenerative medicine.

    PubMed

    Hirschi, Karen K; Li, Song; Roy, Krishnendu

    2014-07-11

    With the discovery of induced pluripotent stem (iPS) cells, it is now possible to convert differentiated somatic cells into multipotent stem cells that have the capacity to generate all cell types of adult tissues. Thus, there is a wide variety of applications for this technology, including regenerative medicine, in vitro disease modeling, and drug screening/discovery. Although biological and biochemical techniques have been well established for cell reprogramming, bioengineering technologies offer novel tools for the reprogramming, expansion, isolation, and differentiation of iPS cells. In this article, we review these bioengineering approaches for the derivation and manipulation of iPS cells and focus on their relevance to regenerative medicine.

  18. Endometrial stem cells in regenerative medicine.

    PubMed

    Verdi, Javad; Tan, Aaron; Shoae-Hassani, Alireza; Seifalian, Alexander M

    2014-01-01

    First described in 2004, endometrial stem cells (EnSCs) are adult stem cells isolated from the endometrial tissue. EnSCs comprise of a population of epithelial stem cells, mesenchymal stem cells, and side population stem cells. When secreted in the menstrual blood, they are termed menstrual stem cells or endometrial regenerative cells. Mounting evidence suggests that EnSCs can be utilized in regenerative medicine. EnSCs can be used as immuno-modulatory agents to attenuate inflammation, are implicated in angiogenesis and vascularization during tissue regeneration, and can also be reprogrammed into induced pluripotent stem cells. Furthermore, EnSCs can be used in tissue engineering applications and there are several clinical trials currently in place to ascertain the therapeutic potential of EnSCs. This review highlights the progress made in EnSC research, describing their mesodermal, ectodermal, and endodermal potentials both in vitro and in vivo.

  19. The onset of regenerative properties in ctenophores.

    PubMed

    Martindale, Mark Q

    2016-10-01

    Ctenophores are a clade of animals that branch off at the base of the animal tree. They have a unique and delicate body plan, and distinct pattern forming mechanisms at different life history stages. They have a stereotyped embryonic cell lineage and are highly 'mosaic' as embryos, but most have amazing capacity to regenerate as adults. Unfortunately, only a handful of ctenophore species have been studied in detail. This review summarizes the key features of the regenerative properties of adults, and the characteristics of the embryological onset of regenerative abilities. The genomes of several ctenophore species have already been sequenced, and these resources set the stage for more detailed cellular and molecular analysis of body plan patterning in this group. Copyright © 2016. Published by Elsevier Ltd.

  20. Endometrial stem cells in regenerative medicine

    PubMed Central

    2014-01-01

    First described in 2004, endometrial stem cells (EnSCs) are adult stem cells isolated from the endometrial tissue. EnSCs comprise of a population of epithelial stem cells, mesenchymal stem cells, and side population stem cells. When secreted in the menstrual blood, they are termed menstrual stem cells or endometrial regenerative cells. Mounting evidence suggests that EnSCs can be utilized in regenerative medicine. EnSCs can be used as immuno-modulatory agents to attenuate inflammation, are implicated in angiogenesis and vascularization during tissue regeneration, and can also be reprogrammed into induced pluripotent stem cells. Furthermore, EnSCs can be used in tissue engineering applications and there are several clinical trials currently in place to ascertain the therapeutic potential of EnSCs. This review highlights the progress made in EnSC research, describing their mesodermal, ectodermal, and endodermal potentials both in vitro and in vivo. PMID:25097665

  1. Unitized Regenerative Fuel Cell System Model Development

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth A.; Jakupca, Ian

    2003-01-01

    A Unitized Regenerative Fuel Cell (URFC) Energy Storage System is being developed at the NASA Glenn Research Center. This URFC system is unique in that it uses the surface area of the hydrogen and oxygen storage tanks as radiating heat surfaces for overall thermal control of the system. The tank surfaces also play an important role in the temperature control of regenerative gas dryers/humidifiers used to dry the hydrogen and oxygen gases produced by electrolysis during the charging and also used to humidify the hydrogen and oxygen gases used by fuel cell during the discharging of the URFCS. A bi- directional pressure controller is used to control the pressure of the oxygen and hydrogen gas inside the URFC stack during both charging and discharging of the URFC system. A water storage accumulator is used to store water reactant and control water pressure inside the URFC stack.

  2. Regenerative endodontics: a road less travelled.

    PubMed

    Bansal, Ramta; Jain, Aditya; Mittal, Sunandan; Kumar, Tarun; Kaur, Dilpreet

    2014-10-01

    Although traditional approaches like root canal therapy and apexification procedures have been successful in treating diseased or infected root canals, but these modalities fail to re-establish healthy pulp tissue in treated teeth. Regeneration-based approaches aims to offer high levels of success by replacing diseased or necrotic pulp tissues with healthy pulp tissue to revitalize teeth. The applications of regenerative approaches in dental clinics have potential to dramatically improve patients' quality of life. This review article offers a detailed overview of present regenerative endodontic approaches aiming to revitalize teeth and also outlines the problems to be dealt before this emerging field contributes to clinical treatment protocols. It conjointly covers the basic trilogy elements of tissue engineering.

  3. Regenerative endodontics: a state of the art.

    PubMed

    Bansal, Rashmi; Bansal, Rajesh

    2011-01-01

    Scientific advances in the creation of restorative biomaterials, in vitro cell culture technology, tissue grafting, tissue engineering, molecular biology and the human genome project provide the basis for the introduction of new technologies into dentistry. Non-vital infected teeth have long been treated with root canal therapy (for mature root apex) and apexification (for immature root apex), or doomed to extraction. Although successful, current treatments fail to re-establish healthy pulp tissue in these teeth. But, what if the non-vital tooth could be made vital once again? That is the hope offered by regenerative endodontics, an emerging field focused on replacing traumatized and diseased pulp with functional pulp tissue. Restoration of vitality of non-vital tooth is based on tissue engineering and revascularization procedures. The purpose of this article is to review these biological procedures and the hurdles that must be overcome to develop regenerative endodontic procedures.

  4. Regenerative Endodontics: A Road Less Travelled

    PubMed Central

    Bansal, Ramta; Mittal, Sunandan; Kumar, Tarun; Kaur, Dilpreet

    2014-01-01

    Although traditional approaches like root canal therapy and apexification procedures have been successful in treating diseased or infected root canals, but these modalities fail to re-establish healthy pulp tissue in treated teeth. Regeneration-based approaches aims to offer high levels of success by replacing diseased or necrotic pulp tissues with healthy pulp tissue to revitalize teeth. The applications of regenerative approaches in dental clinics have potential to dramatically improve patients’ quality of life. This review article offers a detailed overview of present regenerative endodontic approaches aiming to revitalize teeth and also outlines the problems to be dealt before this emerging field contributes to clinical treatment protocols. It conjointly covers the basic trilogy elements of tissue engineering. PMID:25478476

  5. Chemical transdifferentiation: closer to regenerative medicine.

    PubMed

    Xu, Aining; Cheng, Lin

    2016-06-01

    Cell transdifferentiation, which directly switches one type of differentiated cells into another cell type, is more advantageous than cell reprogramming to generate pluripotent cells and differentiate them into functional cells. This process is crucial in regenerative medicine. However, the cell-converting strategies, which mainly depend on the virus-mediated expression of exogenous genes, have clinical safety concerns. Small molecules with compelling advantages are a potential alternative in manipulating cell fate conversion. In this review, we briefly retrospect the nature of cell transdifferentiation and summarize the current developments in the research of small molecules in promoting cell conversion. Particularly, we focus on the complete chemical compound-induced cell transdifferentiation, which is closer to the clinical translation in cell therapy. Despite these achievements, the mechanisms underpinning chemical transdifferentiation remain largely unknown. More importantly, identifying drugs that induce resident cell conversion in vivo to repair damaged tissue remains to be the end-goal in current regenerative medicine.

  6. Regenerative medicine solutions in congenital diaphragmatic hernia.

    PubMed

    De Coppi, Paolo; Deprest, Jan

    2017-06-01

    Congenital diaphragmatic hernia (CDH) remains a major challenge and associated mortality is still significant. Patients have benefited from current therapeutic options, but most severe cases are still associated to poor outcome. Regenerative medicine is emerging as a valid option in many diseases and clinical trials are currently happening for various conditions in children and adults. We report here the advancement in the field which will help both in the understanding of further CDH development and in offering new treatment options for the difficult situations such as repair of large diaphragmatic defects and lung hypoplasia. The authors believe that advancements in regenerative medicine may lead to increase of CDH patients׳ survival. Copyright © 2017. Published by Elsevier Inc.

  7. Micro-Scale Regenerative Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2004-01-01

    A micro-scale regenerative heat exchanger has been designed, optimized and fabricated for use in a micro-Stirling device. Novel design and fabrication techniques enabled the minimization of axial heat conduction losses and pressure drop, while maximizing thermal regenerative performance. The fabricated prototype is comprised of ten separate assembled layers of alternating metal-dielectric composite. Each layer is offset to minimize conduction losses and maximize heat transfer by boundary layer disruption. A grating pattern of 100 micron square non-contiguous flow passages were formed with a nominal 20 micron wall thickness, and an overall assembled ten-layer thickness of 900 microns. Application of the micro heat exchanger is envisioned in the areas of micro-refrigerators/coolers, micropower devices, and micro-fluidic devices.

  8. Induced Pluripotent Stem Cells for Regenerative Medicine

    PubMed Central

    Hirschi, Karen K.; Li, Song; Roy, Krishnendu

    2014-01-01

    With the discovery of induced pluripotent stem (iPS) cells, it is now possible to convert differentiated somatic cells into multipotent stem cells that have the capacity to generate all cell types of adult tissues. Thus, there is a wide variety of applications for this technology, including regenerative medicine, in vitro disease modeling, and drug screening/discovery. Although biological and biochemical techniques have been well established for cell reprogramming, bioengineering technologies offer novel tools for the reprogramming, expansion, isolation, and differentiation of iPS cells. In this article, we review these bioengineering approaches for the derivation and manipulation of iPS cells and focus on their relevance to regenerative medicine. PMID:24905879

  9. Regenerative nanomedicines: an emerging investment prospective?

    PubMed Central

    Prescott, Catherine

    2010-01-01

    Cells respond to their structural surrounding and within nanostructures exhibit unique proliferative and differentiation properties. The application of nanotechnologies to the field of regenerative medicine offers the potential to direct cell fate, target the delivery of cells and reduce immune rejection (via encapsulation), thereby supporting the development of regenerative medicines. The overall objective of any therapy is the delivery of the product not just into the clinic but also to patients on a routine basis. Such a goal typically requires a commercial vehicle and substantial levels of investment in scientific, clinical, regulatory and business expertise, resources, time and funding. Therefore, this paper focuses on some of the challenges facing this emerging industry, including investment by the venture capital community. PMID:20826478

  10. Nanostructured polymeric scaffolds for orthopaedic regenerative engineering.

    PubMed

    Deng, Meng; James, Roshan; Laurencin, Cato T; Kumbar, Sangamesh G

    2012-03-01

    Successful regeneration necessitates the development of three-dimensional (3-D) tissue-inducing scaffolds that mimic the hierarchical architecture of native tissue extracellular matrix (ECM). Cells in nature recognize and interact with the surface topography they are exposed to via ECM proteins. The interaction of cells with nanotopographical features such as pores, ridges, groves, fibers, nodes, and their combinations has proven to be an important signaling modality in controlling cellular processes. Integrating nanotopographical cues is especially important in engineering complex tissues that have multiple cell types and require precisely defined cell-cell and cell-matrix interactions on the nanoscale. Thus, in a regenerative engineering approach, nanoscale materials/scaffolds play a paramount role in controlling cell fate and the consequent regenerative capacity. Advances in nanotechnology have generated a new toolbox for the fabrication of tissue-specific nanostructured scaffolds. For example, biodegradable polymers such as polyesters, polyphosphazenes, polymer blends and composites can be electrospun into ECM-mimicking matrices composed of nanofibers, which provide high surface area for cell attachment, growth, and differentiation. This review provides the fundamental guidelines for the design and development of nanostructured scaffolds for the regeneration of various tissue types in human upper and lower extremities such as skin, ligament, tendon, and bone. Examples focusing on the collective work of our laboratory in those areas are discussed to demonstrate the regenerative efficacy of this approach. Furthermore, preliminary strategies and significant challenges to integrate these individual tissues into one complex organ through regenerative engineering-based integrated graft systems are also discussed.

  11. Regenerative Liquid Propellant Gun Igniter Concepts

    DTIC Science & Technology

    1987-10-01

    AL 35898-5500 Ft Enox , KY 40121 Commander 1 Commiander US Army Belvoir R&D Ctr US Army Development and ATTNt STRBE-WC Eployment Agency Tech Library...REGENERATIVE LIQUID PROPELLANT GUN IGNITER CONCEPTS JOHN D. KNAPTON AVI BIRK JAIMES DESPIRITO CRIS WATSON DTIC E-1FCTE OCTOBER- 1987 SMAR 1 41988D...5 I. INTRODUCTION 1 . BACKGROUND, ........ . . . . . . . . . . . . . . . . . . . 2 . P R O PELL AN T * 6

  12. Regenerative medicine. The industry comes of age.

    PubMed

    Mason, C

    2007-01-01

    The regenerative medicine industry has moved into a new era in which commercialisation and not research is the number one priority. To achieve its new goal, much has had to change, including the introduction of expert business management, simpler but superior products and scalability of manufacture. Mass public and political support is supplying both long-term resources and the market demand to finally create a sustainable new health-care sector.

  13. A solar regenerative thermoelectrochemical converter (RTEC)

    SciTech Connect

    Townsend, C.W.; McHardy, J. )

    1992-02-01

    This is an executive summary of a final subcontract report that describes the successful completion of a closed-loop demonstration of a regenerative thermoelectromechanical device using solar heat input for the production of electricity. The full report, which contains a detailed description of the two-year effort, is currently subject to a government secrecy order which precludes public release of the information. Copies of the full report will be made available for general release whenever the secrecy order is lifted.

  14. Optimization of an irreversible Stirling regenerative cycle

    NASA Astrophysics Data System (ADS)

    Aragón-González, G.; Cano-Bianco, M.; León-Galicia, A.; Rivera-Camacho, J. M.

    2015-01-01

    In this work a Stirling regenerative cycle with some irreversibilities is analyzed. The analyzed irreversibilities are located at the heat exchangers. They receive a finite amount of heat and heat leakage occurs between both reservoirs. Using this model, power and the efficiency at maximum power are obtained. Some optimal design parameters for the exchanger heat areas and thermal conductances are presented. The relation between the power, efficiency and the results obtained are shown graphically.

  15. Ice electrode electrolytic cell

    DOEpatents

    Glenn, David F.; Suciu, Dan F.; Harris, Taryl L.; Ingram, Jani C.

    1993-01-01

    This invention relates to a method and apparatus for removing heavy metals from waste water, soils, or process streams by electrolytic cell means. The method includes cooling a cell cathode to form an ice layer over the cathode and then applying an electric current to deposit a layer of the heavy metal over the ice. The metal is then easily removed after melting the ice. In a second embodiment, the same ice-covered electrode can be employed to form powdered metals.

  16. Ice electrode electrolytic cell

    DOEpatents

    Glenn, D.F.; Suciu, D.F.; Harris, T.L.; Ingram, J.C.

    1993-04-06

    This invention relates to a method and apparatus for removing heavy metals from waste water, soils, or process streams by electrolytic cell means. The method includes cooling a cell cathode to form an ice layer over the cathode and then applying an electric current to deposit a layer of the heavy metal over the ice. The metal is then easily removed after melting the ice. In a second embodiment, the same ice-covered electrode can be employed to form powdered metals.

  17. Solid polymer electrolytes

    DOEpatents

    Abraham, Kuzhikalail M.; Alamgir, Mohamed; Choe, Hyoun S.

    1995-01-01

    This invention relates to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF.sub.3 SO.sub.2).sub.2, LiAsF.sub.6, and LiClO.sub.4.

  18. Electrolyte Concentrates Treat Dehydration

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

  19. Solid polymer electrolytes

    DOEpatents

    Abraham, K.M.; Alamgir, M.; Choe, H.S.

    1995-12-12

    This invention relates to Li ion (Li{sup +}) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF{sub 3}SO{sub 2}){sub 2}, LiAsF{sub 6}, and LiClO{sub 4}. 2 figs.

  20. Thin film composite electrolyte

    DOEpatents

    Schucker, Robert C.

    2007-08-14

    The invention is a thin film composite solid (and a means for making such) suitable for use as an electrolyte, having a first layer of a dense, non-porous conductive material; a second layer of a porous ionic conductive material; and a third layer of a dense non-porous conductive material, wherein the second layer has a Coefficient of thermal expansion within 5% of the coefficient of thermal expansion of the first and third layers.

  1. Ice electrode electrolytic cell

    SciTech Connect

    Glenn, D.F.; Suciu, D.F.; Harris, T.L.; Ingram, J.C.

    1992-12-31

    This invention relates to a method and apparatus for removing heavy metals from waste water, soils, or process streams by electrolytic cell means. The method includes cooling a cell cathode to form an ice layer over the cathode and then applying an electric current to deposit a layer of the heavy metal over the ice. The metal is then easily removed after melting the ice. In a second embodiment, the same ice-covered electrode can be employed to form powdered metals.

  2. Lithium ion conducting electrolytes

    DOEpatents

    Angell, C. Austen; Liu, Changle

    1996-01-01

    A liquid, predominantly lithium-conducting, ionic electrolyte having exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature, and comprising the lithium salts selected from the group consisting of the thiocyanate, iodide, bromide, chloride, perchlorate, acetate, tetrafluoroborate, perfluoromethane sulfonate, perfluoromethane sulfonamide, tetrahaloaluminate, and heptahaloaluminate salts of lithium, with or without a magnesium-salt selected from the group consisting of the perchlorate and acetate salts of magnesium. Certain of the latter embodiments may also contain molecular additives from the group of acetonitrile (CH.sub.3 CN) succinnonitrile (CH.sub.2 CN).sub.2, and tetraglyme (CH.sub.3 --O--CH.sub.2 --CH.sub.2 --O--).sub.2 (or like solvents) solvated to a Mg.sup.+2 cation to lower the freezing point of the electrolyte below room temperature. Other particularly useful embodiments contain up to about 40, but preferably not more than about 25, mol percent of a long chain polyether polymer dissolved in the lithium salts to provide an elastic or rubbery solid electrolyte of high ambient temperature conductivity and exceptional 100.degree. C. conductivity. Another embodiment contains up to about but not more than 10 mol percent of a molecular solvent such as acetone.

  3. Lithium ion conducting electrolytes

    DOEpatents

    Angell, C.A.; Liu, C.

    1996-04-09

    A liquid, predominantly lithium-conducting, ionic electrolyte is described having exceptionally high conductivity at temperatures of 100 C or lower, including room temperature, and comprising the lithium salts selected from the group consisting of the thiocyanate, iodide, bromide, chloride, perchlorate, acetate, tetrafluoroborate, perfluoromethane sulfonate, perfluoromethane sulfonamide, tetrahaloaluminate, and heptahaloaluminate salts of lithium, with or without a magnesium-salt selected from the group consisting of the perchlorate and acetate salts of magnesium. Certain of the latter embodiments may also contain molecular additives from the group of acetonitrile (CH{sub 3}CN), succinnonitrile (CH{sub 2}CN){sub 2}, and tetraglyme (CH{sub 3}--O--CH{sub 2}--CH{sub 2}--O--){sub 2} (or like solvents) solvated to a Mg{sup +2} cation to lower the freezing point of the electrolyte below room temperature. Other particularly useful embodiments contain up to about 40, but preferably not more than about 25, mol percent of a long chain polyether polymer dissolved in the lithium salts to provide an elastic or rubbery solid electrolyte of high ambient temperature conductivity and exceptional 100 C conductivity. Another embodiment contains up to about but not more than 10 mol percent of a molecular solvent such as acetone. 2 figs.

  4. Common ethical issues in regenerative medicine.

    PubMed

    Awaya, Tsuyoshi

    2005-01-01

    One of the common ethical issues in regenerative medicine is progress in 'componentation' (= being treated as parts) of the human body, and the enhancement of the view of such "human body parts." 'Componentation' of the human body represents a preliminary step toward commodification of the human body. The process of commodification of the human body follows the steps of 'materialization' (= being treated as a material object) [first step] -- 'componentation' [second step] -- 'resourcialization' (= being treated as resources) [third step] -- commodification [fourth step]. Transplantation medicine and artificial organ developments have dramatically exposed the potential of organs and tissues as parts, and regenerative medicine has a role in advancing 'componentation' of the human body and further enhancing the view of human body parts. The 'componentation' of the human body, regardless of the degree of regenerative medicine's contribution to it, is considered as a challenge to the traditional view of human bodies and the abstract value of "Human Dignity" in the same way or alongside the 'resourcialization' and commodification. However, in the future, a new perspective of human bodies that means "a perspective whereby human bodies, organs, tissues, and even the bodies themselves are perceived as disposable tools like disposable cameras, syringes, or contact lens" and therefore a new ethical view, suitable for a new reality, may emerge.

  5. Mesenchymal stem cells in regenerative rehabilitation.

    PubMed

    Nurkovic, Jasmin; Dolicanin, Zana; Mustafic, Fahrudin; Mujanovic, Rifat; Memic, Mensur; Grbovic, Vesna; Skevin, Aleksandra Jurisic; Nurkovic, Selmina

    2016-06-01

    [Purpose] Regenerative medicine and rehabilitation contribute in many ways to a specific plan of care based on a patient's medical status. The intrinsic self-renewing, multipotent, regenerative, and immunosuppressive properties of mesenchymal stem cells offer great promise in the treatment of numerous autoimmune, degenerative, and graft-versus-host diseases, as well as tissue injuries. As such, mesenchymal stem cells represent a therapeutic fortune in regenerative medicine. The aim of this review is to discuss possibilities, limitations, and future clinical applications of mesenchymal stem cells. [Subjects and Methods] The authors have identified and discussed clinically and scientifically relevant articles from PubMed that have met the inclusion criteria. [Results] Direct treatment of muscle injuries, stroke, damaged peripheral nerves, and cartilage with mesenchymal stem cells has been demonstrated to be effective, with synergies seen between cellular and physical therapies. Over the past few years, several researchers, including us, have shown that there are certain limitations in the use of mesenchymal stem cells. Aging and spontaneous malignant transformation of mesenchymal stem cells significantly affect the functionality of these cells. [Conclusion] Definitive conclusions cannot be made by these studies because limited numbers of patients were included. Studies clarifying these results are expected in the near future.

  6. Upconversion Nanoparticles for Bioimaging and Regenerative Medicine

    PubMed Central

    González-Béjar, María; Francés-Soriano, Laura; Pérez-Prieto, Julia

    2016-01-01

    Nanomaterials are proving useful for regenerative medicine in combination with stem cell therapy. Nanoparticles (NPs) can be administrated and targeted to desired tissues or organs and subsequently be used in non-invasive real-time visualization and tracking of cells by means of different imaging techniques, can act as therapeutic agent nanocarriers, and can also serve as scaffolds to guide the growth of new tissue. NPs can be of different chemical nature, such as gold, iron oxide, cadmium selenide, and carbon, and have the potential to be used in regenerative medicine. However, there are still many issues to be solved, such as toxicity, stability, and resident time. Upconversion NPs have relevant properties such as (i) low toxicity, (ii) capability to absorb light in an optical region where absorption in tissues is minimal and penetration is optimal (note they can also be designed to emit in the near-infrared region), and (iii) they can be used in multiplexing and multimodal imaging. An overview on the potentiality of upconversion materials in regenerative medicine is given. PMID:27379231

  7. Allogenicity & immunogenicity in regenerative stem cell therapy

    PubMed Central

    Charron, Dominique

    2013-01-01

    The development of regenerative medicine relies in part on the capacity of stem cells to differentiate into specialized cell types and reconstitute tissues and organs. The origin of the stem cells matters. While autologous cells were initially the preferred ones the need for “off the shelf” cells is becoming prevalent. These cells will be immediately available and they originate from young non diseased individuals. However their allogenicity can be viewed as a limitation to their use. Recent works including our own show that allogenicity of stem cell can be viewed as on one hand detrimental leading to their elimination and on the other hand beneficial through a paracrine effect that can induce a local tissue regenerative effect from endogenous stem cells. Also their immune modulatory capacity can be harnessed to favor regeneration. Therefore the immune phenotype of stem cells is an important criteria to be considered before their clinical use. Immuno monitoring of the consequences of their in vivo injection needs to be taken into account. Transplantation immunology knowledge will be instrumental to enable the development of safe personalized regenerative stem cell therapy. PMID:24434327

  8. Allogenicity & immunogenicity in regenerative stem cell therapy.

    PubMed

    Charron, Dominique

    2013-11-01

    The development of regenerative medicine relies in part on the capacity of stem cells to differentiate into specialized cell types and reconstitute tissues and organs. The origin of the stem cells matters. While autologous cells were initially the preferred ones the need for "off the shelf" cells is becoming prevalent. These cells will be immediately available and they originate from young non diseased individuals. However their allogenicity can be viewed as a limitation to their use. Recent works including our own show that allogenicity of stem cell can be viewed as on one hand detrimental leading to their elimination and on the other hand beneficial through a paracrine effect that can induce a local tissue regenerative effect from endogenous stem cells. Also their immune modulatory capacity can be harnessed to favor regeneration. Therefore the immune phenotype of stem cells is an important criteria to be considered before their clinical use. Immuno monitoring of the consequences of their in vivo injection needs to be taken into account. Transplantation immunology knowledge will be instrumental to enable the development of safe personalized regenerative stem cell therapy.

  9. An animal model to study regenerative endodontics.

    PubMed

    Torabinejad, Mahmoud; Corr, Robert; Buhrley, Matthew; Wright, Kenneth; Shabahang, Shahrokh

    2011-02-01

    A growing body of evidence is demonstrating the possibility for regeneration of tissues within the pulp space and continued root development in teeth with necrotic pulps and open apices. There are areas of research related to regenerative endodontics that need to be investigated in an animal model. The purpose of this study was to investigate ferret cuspid teeth as a model to investigate factors involved in regenerative endodontics. Six young male ferrets between the ages of 36-133 days were used in this investigation. Each animal was anesthetized and perfused with 10% buffered formalin. Block sections including the mandibular and maxillary cuspid teeth and their surrounding periapical tissues were obtained, radiographed, decalcified, sectioned, and stained with hematoxylin-eosin to determine various stages of apical closure in these teeth. The permanent mandibular and maxillary cuspid teeth with open apices erupted approximately 50 days after birth. Initial signs of closure of the apical foramen in these teeth were observed between 90-110 days. Complete apical closure was observed in the cuspid teeth when the animals were 133 days old. Based on the experiment, ferret cuspid teeth can be used to investigate various factors involved in regenerative endodontics that cannot be tested in human subjects. The most appropriate time to conduct the experiments would be when the ferrets are between the ages of 50 and 90 days. Copyright © 2011. Published by Elsevier Inc.

  10. Regenerative implantable medical devices: an overview.

    PubMed

    Yu, Shu-Yang; Li, Fu-Yao; Wang, Hong-Man

    2016-06-01

    To conduct a bibliometric evaluation and trend prediction of English literature on animal-derived regenerative implantable medical devices based on tissue engineering technology. Data identified by a search strategy with eleven combinations of keywords before 1 January, 2014 were downloaded from eight databases on 25 November, 2014. The study analysed publication year, journal preference, authors' geographic location and research topics. Research on animal-derived regenerative implantable medical devices is gradually increasing. The majority of the first authors are from colleges or universities. Approximately one-third of the papers were the result of cooperation of different institutions. The top five productive countries are the United States, China, UK, Germany and Italy. Biomaterials are the main literature source. Bradford's law analysis shows that a core journal area has formed. The active areas of research and future research directions are 'scaffold materials', 'biocompatibility', 'growth factors' and 'extracellular matrix'. Research of animal-derived regenerative implantable medical devices has attracted more and more attention from the academia. But most of the research achievements are generated by a few developed countries. Researchers around the world need to complement each other in knowledge and academic resources by communication and cooperation. © 2016 Health Libraries Group.

  11. Regenerative magnetorheological dampers for vehicle suspensions

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Zou, Li; Liao, Wei-Hsin

    2015-04-01

    Magnetorheological (MR) dampers are promising for vehicle suspensions, by virtue of their adaptive properties. During the everyday use of vehicles, a lot of energy is wasted due to the energy dissipation by dampers under the road irregularities. On the other hand, extra batteries are required for the current MR damper systems. To reduce the energy waste and get rid of the dependence on extra batteries, in this paper, regenerative MR dampers are proposed for vehicle suspensions, which integrate energy harvesting and controllable damping functions. The wasted vibration energy can be converted into electrical energy and power the MR damper coil. A regenerative MR damper for vehicle suspensions is developed. Damping force and power generation characteristics of the regenerative MR damper were modeled and analyzed. Then the damper is applied to a 2 DOF suspension system for system simulation under various road conditions. Simulation results show that riding comfort can be significantly improved, while harvesting energy for other use in addition to supply power for the controlled MR damper.

  12. Mesenchymal stem cells in regenerative rehabilitation

    PubMed Central

    Nurkovic, Jasmin; Dolicanin, Zana; Mustafic, Fahrudin; Mujanovic, Rifat; Memic, Mensur; Grbovic, Vesna; Skevin, Aleksandra Jurisic; Nurkovic, Selmina

    2016-01-01

    [Purpose] Regenerative medicine and rehabilitation contribute in many ways to a specific plan of care based on a patient’s medical status. The intrinsic self-renewing, multipotent, regenerative, and immunosuppressive properties of mesenchymal stem cells offer great promise in the treatment of numerous autoimmune, degenerative, and graft-versus-host diseases, as well as tissue injuries. As such, mesenchymal stem cells represent a therapeutic fortune in regenerative medicine. The aim of this review is to discuss possibilities, limitations, and future clinical applications of mesenchymal stem cells. [Subjects and Methods] The authors have identified and discussed clinically and scientifically relevant articles from PubMed that have met the inclusion criteria. [Results] Direct treatment of muscle injuries, stroke, damaged peripheral nerves, and cartilage with mesenchymal stem cells has been demonstrated to be effective, with synergies seen between cellular and physical therapies. Over the past few years, several researchers, including us, have shown that there are certain limitations in the use of mesenchymal stem cells. Aging and spontaneous malignant transformation of mesenchymal stem cells significantly affect the functionality of these cells. [Conclusion] Definitive conclusions cannot be made by these studies because limited numbers of patients were included. Studies clarifying these results are expected in the near future. PMID:27390452

  13. Regenerative endodontics--Creating new horizons.

    PubMed

    Dhillon, Harnoor; Kaushik, Mamta; Sharma, Roshni

    2016-05-01

    Trauma to the dental pulp, physical or microbiologic, can lead to inflammation of the pulp followed by necrosis. The current treatment modality for such cases is non-surgical root canal treatment. The damaged tissue is extirpated and the root canal system prepared. It is then obturated with an inert material such a gutta percha. In spite of advances in techniques and materials, 10%-15% of the cases may end in failure of treatment. Regenerative endodontics combines principles of endodontics, cell biology, and tissue engineering to provide an ideal treatment for inflamed and necrotic pulp. It utilizes mesenchymal stem cells, growth factors, and organ tissue culture to provide treatment. Potential treatment modalities include induction of blood clot for pulp revascularization, scaffold aided regeneration, and pulp implantation. Although in its infancy, successful treatment of damaged pulp tissue has been performed using principles of regenerative endodontics. This field is dynamic and exciting with the ability to shape the future of endodontics. This article highlights the fundamental concepts, protocol for treatment, and possible avenues for research in regenerative endodontics. © 2015 Wiley Periodicals, Inc.

  14. Electrolyte materials - Issues and challenges

    SciTech Connect

    Balbuena, Perla B.

    2014-06-16

    Electrolytes are vital components of an electrochemical energy storage device. They are usually composed of a solvent or mixture of solvents and a salt or a mixture of salts which provide the appropriate environment for ionic conduction. One of the main issues associated with the selection of a proper electrolyte is that its electronic properties have to be such that allow a wide electrochemical window - defined as the voltage range in which the electrolyte is not oxidized or reduced - suitable to the battery operating voltage. In addition, electrolytes must have high ionic conductivity and negligible electronic conductivity, be chemically stable with respect to the other battery components, have low flammability, and low cost. Weak stability of the electrolyte against oxidation or reduction leads to the formation of a solid-electrolyte interphase (SEI) layer at the surface of the cathode and anode respectively. Depending on the materials of the electrolyte and those of the electrode, the SEI layer may be composed by combinations of organic and inorganic species, and it may exert a passivating role. In this paper we discuss the current status of knowledge about electrolyte materials, including non-aqueous liquids, ionic liquids, solid ceramic and polymer electrolytes. We also review the basic knowledge about the SEI layer formation, and challenges for a rational design of stable electrolytes.

  15. New glossary of terms used in regenerative medicine: standardization continues to emerge as regenerative medicine matures.

    PubMed

    Sheridan, Ben; Harris, Neil

    2009-07-01

    Regenerative medicine is an evolving, cross-disciplinary, international field that, as a result, uses terms that are either not widely understood, or may have a number of different meanings. Many stakeholders have identified this lack of clarity as a potential barrier to effective communication within the field. To address this, BSI British Standards, supported by the UK Department for Innovation, Universities and Skills (DIUS), was commissioned to develop guidance on the definitions of terms used within regenerative medicine. The resulting document aims to provide clear consensus terminology to improve communication and facilitate a common understanding for a broad range of potential users.

  16. Ceramic electrolyte coating and methods

    DOEpatents

    Seabaugh, Matthew M.; Swartz, Scott L.; Dawson, William J.; McCormick, Buddy E.

    2007-08-28

    Aqueous coating slurries useful in depositing a dense coating of a ceramic electrolyte material (e.g., yttrium-stabilized zirconia) onto a porous substrate of a ceramic electrode material (e.g., lanthanum strontium manganite or nickel/zirconia) and processes for preparing an aqueous suspension of a ceramic electrolyte material and an aqueous spray coating slurry including a ceramic electrolyte material. The invention also includes processes for depositing an aqueous spray coating slurry including a ceramic electrolyte material onto pre-sintered, partially sintered, and unsintered ceramic substrates and products made by this process.

  17. Solid state electrolyte systems

    SciTech Connect

    Pederson, L.R.; Armstrong, B.L.; Armstrong, T.R.

    1997-12-01

    Lanthanum gallates are a new family of solid electrolytes that exhibit high ionic conductivity and are stable to high temperatures. Compositions have been developed that are as much as a factor of two more conductive than yttria-stabilized zirconia at a given temperature, through partial replacement of lanthanum by calcium, strontium, and/or barium and through partial replacement of gallium by magnesium. Oxide powders were prepared using combustion synthesis techniques developed in this laboratory; these were sintered to >95% of theoretical density and consisted of a single crystalline phase. Electrical conductivities, electron and ion transference numbers, thermal expansion, and phase behavior were evaluated as a function of temperature and oxygen partial pressure. A key advantage of the use of lanthanum gallate electrolytes in solid oxide fuel cells is that the temperature of operation may be lowered to perhaps 800 C, yet provide approximately the same power density as zirconia-based cells operating at 1000 C. Ceramic electrolytes that conduct both oxygen ions and electrons are potentially useful to passively separate pure oxygen from an air source at low cost. In such materials, an oxygen ion flux in one direction is charge-compensated by an opposing electron flux. The authors have examined a wide range of mixed ion and electron conducting perovskite ceramics in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, where M = Sr, Ca, and Ba, and N = Pr, Mn, Ni, Cu, Ti, and Al, as well as mixed conducting brownmillerite ceramics, and have characterized oxygen permeation behavior, defect chemistry, structural and phase stability, and performance as cathodes.

  18. Diode-pumped regenerative Yb:SrF2 amplifier

    NASA Astrophysics Data System (ADS)

    Ricaud, S.; Georges, P.; Camy, P.; Doualan, J.-L.; Moncorgé, R.; Courjaud, A.; Mottay, E.; Druon, F.

    2012-03-01

    We report what we believe to be the first Yb:SrF2 regenerative femtosecond amplifier. The regenerative amplifier produces 325-fs pulses at 100-Hz repetition rate with an energy before compression of 1.4 mJ. The interest of Yb:SrF2 in such regenerative amplifiers and its complementarity to its well-known isotype Yb:CaF2 is also discussed.

  19. Electrolytic oxide reduction system

    DOEpatents

    Wiedmeyer, Stanley G; Barnes, Laurel A; Williamson, Mark A; Willit, James L; Berger, John F

    2015-04-28

    An electrolytic oxide reduction system according to a non-limiting embodiment of the present invention may include a plurality of anode assemblies, a plurality of cathode assemblies, and a lift system configured to engage the anode and cathode assemblies. The cathode assemblies may be alternately arranged with the anode assemblies such that each cathode assembly is flanked by two anode assemblies. The lift system may be configured to selectively engage the anode and cathode assemblies so as to allow the simultaneous lifting of any combination of the anode and cathode assemblies (whether adjacent or non-adjacent).

  20. Electrolytic pressure transduction system

    NASA Astrophysics Data System (ADS)

    Bryant, G. H.

    1985-12-01

    This invention is directed to a Wheatstone bridge circuit for measuring pressure in the distal esophageal sphincter (D.E.S.) as well as in other organs and bodily cavities. A flexible hollow tube having three spaced electrodes is lodged in the esophagus. The tube is partly filled with a saline solution to cover the electrodes, thereby producing two series connected, pressure sensitive resistors. The electrolytic resistors are coupled to two series connected fixed resistors to complete the bridge circuit. Electrical imbalances in the bridge circuit are measured in terms of the pressure corresponding to the pressure applied by the D.E.S.

  1. Glass electrolyte composition

    DOEpatents

    Kucera, G.H.; Roche, M.F.

    1985-01-08

    An ionically conductive glass is disclosed for use as electrolyte in a high temperature electrochemical cell, particularly a cell with sodium anode and sulfur cathode. The glass includes the constituents Na/sub 2/O, ZrO/sub 2/, Al/sub 2/O/sub 3/ and SiO/sub 2/ in selected proportions to be a single phase solid solution substantially free of crystalline regions and undissolved constituents. Other advantageous properties are an ionic conductivity in excess of 2 x 10/sup -3/ (ohm-cm)/sup -1/ at 300/sup 0/C and a glass transition temperature in excess of 500/sup 0/C.

  2. Glass electrolyte composition

    DOEpatents

    Kucera, Gene H.; Roche, Michael F.

    1985-01-01

    An ionically conductive glass is disclosed for use as electrolyte in a high temperature electrochemical cell, particularly a cell with sodium anode and sulfur cathode. The glass includes the constituents Na.sub.2 O, ZrO.sub.2, Al.sub.2 O.sub.3 and SiO.sub.2 in selected proportions to be a single phase solid solution substantially free of crystalline regions and undissolved constituents. Other advantageous properties are an ionic conductivity in excess of 2.times.10.sup.-3 (ohm-cm).sup.-1 at 300.degree. C. and a glass transition temperature in excess of 500.degree. C.

  3. Platelet rich fibrin - a novel acumen into regenerative endodontic therapy

    PubMed Central

    Sharma, Krishna

    2014-01-01

    Research into regenerative dentistry has added impetus onto the field of molecular biology. It can be documented as a prototype shift in the therapeutic armamentarium for dental disease. Regenerative endodontic procedures are widely being added to the current armamentarium of pulp therapy procedures. The regenerative potential of platelets has been deliberated. A new family of platelet concentrates called the platelet rich fibrin (PRF) has been recently used by several investigators and has shown application in diverse disciplines of dentistry. This paper is intended to add light on the various prospects of PRF and clinical insights to regenerative endodontic therapy. PMID:24516822

  4. A Regeneratively-Cooled Thrust Chamber for the Fastrac Engine

    NASA Technical Reports Server (NTRS)

    Brown, Kendall; Sparks, Dave; Woodcock, Gordon; Jim Turner (Technical Monitor)

    2000-01-01

    This document consists of presentation slides about the development of the regeneratively cooled thrust chamber for the Fastrac engine. The Fastrac engine was originally developed to demonstrate low cost design and fabrication methods. It was intended to be used in an expendable booster. The regen thrust chamber enables a more cost efficient test program. Using the low cost design and fabrication methodology designed for the 12K regeneratively cooled chamber, the contractor designed, developed and fabricated a regeneratively cooled thrust chamber for the Fastrac engine.

  5. [Nodular regenerative hyperplasia associated with primary antiphospholipid syndrome].

    PubMed

    Cadranel, J F; Demontis, R; Guettier, C; Bouraya, D; Dautreaux, M; Ghazali, A; Poux, J M; Coutarel, P; Devergie, B; Fievet, P

    1996-01-01

    Nodular regenerative hyperplasia of the liver is characterized by diffuse nodularity of the hepatic parenchyma without fibrotic septa. It may be related to venous or arterial obstruction in the portal tract. We report a case of primary antiphospholipid syndrome associated with nodular regenerative hyperplasia in a 45-year old woman. The patient had an ischemic stroke, associated with an acute arterial ischemia of the left leg. She had high titers of serum anticardiolipin antibodies. Nodular regenerative hyperplasia of the liver was histologically confirmed and was associated with anicteric cholestasis. This case provides additional evidence that a thrombotic mechanism may play a role in the pathogenesis of nodular regenerative hyperplasia of the liver.

  6. Could we also be regenerative superheroes, like salamanders?

    PubMed

    Dall'Agnese, Alessandra; Puri, Pier Lorenzo

    2016-09-01

    Development of methods to reawaken the semi-dormant regenerative potential that lies within adult human tissues would hold promise for the restoration of diseased or damaged organs and tissues. While most of the regeneration potential is suppressed in many vertebrates, including humans, during adult life, urodele amphibians (salamanders) retain their regenerative ability throughout adulthood. Studies in newts and axolotls, two salamander models, have provided significant knowledge about adult limb regeneration. In this review, we present a comparative analysis of salamander and mammalian regeneration and discuss how evolutionarily altered properties of the regenerative environment can be exploited to restore full regenerative potential in the human body.

  7. Platelet rich fibrin - a novel acumen into regenerative endodontic therapy.

    PubMed

    Hotwani, Kavita; Sharma, Krishna

    2014-02-01

    Research into regenerative dentistry has added impetus onto the field of molecular biology. It can be documented as a prototype shift in the therapeutic armamentarium for dental disease. Regenerative endodontic procedures are widely being added to the current armamentarium of pulp therapy procedures. The regenerative potential of platelets has been deliberated. A new family of platelet concentrates called the platelet rich fibrin (PRF) has been recently used by several investigators and has shown application in diverse disciplines of dentistry. This paper is intended to add light on the various prospects of PRF and clinical insights to regenerative endodontic therapy.

  8. Clinical concepts for regenerative therapy in furcations.

    PubMed

    Sanz, Mariano; Jepsen, Karin; Eickholz, Peter; Jepsen, Søren

    2015-06-01

    Furcation involvements present one of the greatest challenges in periodontal therapy because furcation-involved molar teeth respond less favorably to conventional periodontal therapy compared with noninvolved molar or nonmolar teeth. Various regenerative procedures have been proposed and applied with the aim of eliminating the furcation defect or reducing the furcation depth. An abundance of studies and several systematic reviews have established the effectiveness of membrane therapy (guided tissue regeneration) for buccal Class II furcation involvement of mandibular and maxillary molars compared with open flap surgery. Bone grafts/substitutes may enhance the results of guided tissue regeneration. However, complete furcation closure is not a predictable outcome. Limited data and no meta-analyses are available on the effects of enamel matrix proteins for furcation regeneration. Enamel matrix protein therapy has demonstrated clinical improvements in the treatment of buccal Class II furcation defects in mandibular molars; however, complete closure of the furcation lesion is achieved only in a minority of cases. Neither guided tissue regeneration nor enamel matrix protein therapy have demonstrated predictable results for approximal Class II and for Class III furcations. Promising preclinical data from furcation regeneration studies in experimental animals is available for growth factor- and differentiation factor-based technologies, but very limited data are available from human clinical studies. Although cell-based therapies have received considerable attention in regenerative medicine, their experimental evaluation in the treatment of periodontal furcation lesions is at a very early stage of development. In summary, the indications and the limitations for currently available treatment modalities for furcation defects are well established. New regenerative treatments are clearly needed to improve the predictability of a complete resolution of furcation defects.

  9. Cellular cardiac regenerative therapy in which patients?

    PubMed

    Chachques, Juan C

    2009-08-01

    Cell-based myocardial regenerative therapy is undergoing experimental and clinical trials in order to limit the consequences of decreased contractile function and compliance of damaged ventricles owing to ischemic and nonischemic myocardial diseases. A variety of myogenic and angiogenic cell types have been proposed, such as skeletal myoblasts, mononuclear and mesenchymal bone marrow cells, circulating blood-derived progenitors, adipose-derived stromal cells, induced pluripotent stem cells, umbilical cord cells, endometrial mesenchymal stem cells, adult testis pluripotent stem cells and embryonic cells. Current indications for stem cell therapy concern patients who have had a left- or right-ventricular infarction or idiopathic dilated cardiomyopathies. Other indications and potential applications include patients with diabetic cardiomyopathy, Chagas heart disease (American trypanosomiasis), ischemic mitral regurgitation, left ventricular noncompacted myocardium and pediatric cardiomyopathy. Suitable sources of cells for cardiac implant will depend on the types of diseases to be treated. For acute myocardial infarction, a cell that reduces myocardial necrosis and augments vascular blood flow will be desirable. For heart failure, cells that replace or promote myogenesis, reverse apoptopic mechanisms and reactivate dormant cell processes will be useful. It is important to note that stem cells are not an alternative to heart transplantation; selected patients should be in an early stage of heart failure as the goal of this regenerative approach is to avoid or delay organ transplantation. Since the cell niche provides crucial support needed for stem cell maintenance, the most interesting and realistic perspectives include the association of intramyocardial cell transplantation with tissue-engineered scaffolds and multisite cardiac pacing in order to transform a passive regenerative approach into a 'dynamic cellular support', a promising method for the creation of

  10. Regenerative Blower for EVA Suit Ventilation Fan

    NASA Technical Reports Server (NTRS)

    Izenson, Michael G.; Chen, Weibo; Paul, Heather L.

    2010-01-01

    Portable life support systems in future space suits will include a ventilation subsystem driven by a dedicated fan. This ventilation fan must meet challenging requirements for pressure rise, flow rate, efficiency, size, safety, and reliability. This paper describes research and development that showed the feasibility of a regenerative blower that is uniquely suited to meet these requirements. We proved feasibility through component tests, blower tests, and design analysis. Based on the requirements for the Constellation Space Suit Element (CSSE) Portable Life Support System (PLSS) ventilation fan, we designed the critical elements of the blower. We measured the effects of key design parameters on blower performance using separate effects tests, and used the results of these tests to design a regenerative blower that will meet the ventilation fan requirements. We assembled a proof-of-concept blower and measured its performance at sub-atmospheric pressures that simulate a PLSS ventilation loop environment. Head/flow performance and maximum efficiency point data were used to specify the design and operating conditions for the ventilation fan. We identified materials for the blower that will enhance safety for operation in a lunar environment, and produced a solid model that illustrates the final design. The proof-of-concept blower produced the flow rate and pressure rise needed for the CSSE ventilation subsystem while running at 5400 rpm, consuming only 9 W of electric power using a non-optimized, commercial motor and controller and inefficient bearings. Scaling the test results to a complete design shows that a lightweight, compact, reliable, and low power regenerative blower can meet the performance requirements for future space suit life support systems.

  11. Electrolyte creepage barrier for liquid electrolyte fuel cells

    DOEpatents

    Li, Jian; Farooque, Mohammad; Yuh, Chao-Yi

    2008-01-22

    A dielectric assembly for electrically insulating a manifold or other component from a liquid electrolyte fuel cell stack wherein the dielectric assembly includes a substantially impermeable dielectric member over which electrolyte is able to flow and a barrier adjacent the dielectric member and having a porosity of less than 50% and greater than 10% so that the barrier is able to measurably absorb and chemically react with the liquid electrolyte flowing on the dielectric member to form solid products which are stable in the liquid electrolyte. In this way, the barrier inhibits flow or creepage of electrolyte from the dielectric member to the manifold or component to be electrically insulated from the fuel cell stack by the dielectric assembly.

  12. Regenerative nanotechnology in oral and maxillofacial surgery.

    PubMed

    Shakib, Kaveh; Tan, Aaron; Soskic, Vukic; Seifalian, Alexander M

    2014-12-01

    Regenerative nanotechnology is at the forefront of medical research, and translational medicine is a challenge to both scientists and clinicians. Although there has been an exponential rise in the volume of research generated about it for both medical and surgical uses, key questions remain about its actual benefits. Nevertheless, some people think that therapeutics based on its principles may form the core of applied research for the future. Here we give an account of its current use in oral and maxillofacial surgery, and implications and challenges for the future. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. Transpiration And Regenerative Cooling Of Rocket Engine

    NASA Technical Reports Server (NTRS)

    Obrien, Charles J.

    1989-01-01

    Transpiration cooling extends limits of performance. Addition of transpiration cooling to regeneratively-cooled rocket-engine combustion chamber proposed. Modification improves performance of engine by allowing use of higher chamber pressure. Throat section of combustion-chamber wall cooled by transpiration, while chamber and nozzle sections cooled by fluid flowing in closed channels. Concept applicable to advanced, high-performance terrestrial engines or some kinds of industrial combustion chambers. With proper design, cooling scheme makes possible to achieve higher chamber pressure and higher overall performance in smaller engine.

  14. Regulating the therapeutic translation of regenerative medicine.

    PubMed

    Cuchiara, Maude L; Olive, Jackie K; Matthews, Kirstin

    2015-01-01

    Regenerative medicine and stem cell research are exciting new fields. But as the fields progress toward clinical therapies, controversies emerge. Hype surrounding stem cell research has caused an increase in their use in interventions that are not clinically proven. Furthermore, the regulatory agencies have a lot of difficulty dealing with cell therapies, which are distinctly different from drugs and medical devices they more commonly approve. To move the field forward, advocates, regulators and scientists need to come together to find new options for stem cell research oversight that protects both the patients and the research field.

  15. Phosphorous-Containing Polymers for Regenerative Medicine

    PubMed Central

    Watson, Brendan M.; Kasper, F. Kurtis; Mikos, Antonios G.

    2014-01-01

    Disease and injury have resulted in a large, unmet need for functional tissue replacements. Polymeric scaffolds can be used to deliver cells and bioactive signals to address this need for regenerating damaged tissue. Phosphorous-containing polymers have been implemented to improve and accelerate the formation of native tissue both by mimicking the native role of phosphorous groups in the body and by attachment of other bioactive molecules. This manuscript reviews the synthesis, properties, and performance of phosphorous-containing polymers that can be useful in regenerative medicine applications. PMID:24565855

  16. The essential materials paradigms for regenerative medicine

    NASA Astrophysics Data System (ADS)

    Williams, David

    2011-04-01

    Medical technology is changing rapidly. Several disease states can now be treated very effectively by implantable devices that restore mechanical and physical functionality, such as replacement of hip joints or restoration of heart rhythms by pacemakers. These techniques, however, are rather limited, and no biological functionality can be restored through the use of inert materials and devices. This paper explores the role of new types of biomaterials within the emerging area of regenerative medicine, where they are able to play a powerful role in persuading the human body to regenerate itself.

  17. Regenerative fuel cell systems for space station

    NASA Technical Reports Server (NTRS)

    Hoberecht, M. A.; Sheibley, D. W.

    1985-01-01

    Regenerative fuel cell (RFC) systems are the leading energy storage candidates for Space Station. Key design features are the advanced state of technology readiness and high degree of system level design flexibility. Technology readiness was demonstrated through testing at the single cell, cell stack, mechanical ancillary component, subsystem, and breadboard levels. Design flexibility characteristics include independent sizing of power and energy storage portions of the system, integration of common reactants with other space station systems, and a wide range of various maintenance approaches. The design features led to selection of a RFC system as the sole electrochemical energy storage technology option for the space station advanced development program.

  18. Collagen: a network for regenerative medicine

    PubMed Central

    Pawelec, K. M.; Best, S. M.

    2016-01-01

    The basic building block of the extra-cellular matrix in native tissue is collagen. As a structural protein, collagen has an inherent biocompatibility making it an ideal material for regenerative medicine. Cellular response, mediated by integrins, is dictated by the structure and chemistry of the collagen fibers. Fiber formation, via fibrillogenesis, can be controlled in vitro by several factors: pH, ionic strength, and collagen structure. After formation, fibers are stabilized via cross-linking. The final bioactivity of collagen scaffolds is a result of both processes. By considering each step of fabrication, scaffolds can be tailored for the specific needs of each tissue, improving their therapeutic potential. PMID:27928505

  19. The strong financial case for regenerative medicine and the regen industry.

    PubMed

    Mason, Chris; Dunnill, Peter

    2008-05-01

    Although the therapeutic promise of regenerative medicine is immensely exciting, the cost of product development, and particularly of clinical trials, for the more demanding applications will be high. For this reason it is vital for scientists and start-ups who wish to see their ideas implemented to be able to convince established major pharmaceutical or device companies with the necessary 'deep pockets' that the expenditure can yield an appropriate return. It also means that governments and health insurance companies must see a gain in funding regenerative medicine for patients. To address this issue the costs of five major medical conditions that could benefit from regenerative medicine have been defined for the USA as an illustration. This choice of country was made as potentially the largest initial market and one where the billing system for healthcare allows access to individual direct and some indirect costs. The data are complemented by a number of relevant examples of costs per quality-adjusted life year to indicate where current treatment methods are weak or strong. Finally, the relationship of the nascent regen* industry to the pharma and medical device sectors is summarized to assess the challenge of encouraging their involvement.

  20. Electrolytic pretreatment of urine

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Electrolysis has been under evaluation for several years as a process to pretreat urine for ultimate recovery of potable water in manned spacecraft applications. The conclusions that were drawn from this investigation are the following: (1) A platinum alloy containing 10 percent rhodium has been shown to be an effective, corrosion-resistant anode material for the electrolytic pretreatment of urine. Black platinum has been found to be suitable as a cathode material. (2) The mechanism of the reactions occurring during the electrolysis of urine is two-stage: (a) a total Kjeldahl nitrogen and total organic carbon (TOC) removal in the first stage is the result of electrochemical oxidation of urea to CO2, H2O, and ammonia followed by chloride interaction to produce N2 from ammonia, (b) after the urea has been essentially removed and the chloride ions have no more ammonia to interact with, the chloride ions start to oxidize to higher valence states, thus producing perchlorates. (3) Formation of perchlorates can be suppressed by high/low current operation, elevated temperature, and pH adjustment. (4) UV-radiation showed promise in assisting electrolytic TOC removal in beaker tests, but was not substantiated in limited single cell testing. This may have been due to non-optimum configurations of the single cell test rig and the light source.

  1. Platelet additive solution - electrolytes.

    PubMed

    Azuma, Hiroshi; Hirayama, Junichi; Akino, Mitsuaki; Ikeda, Hisami

    2011-06-01

    Recent attention to solutions that replace most or all plasma in platelet concentrates, while maintaining satisfactory platelet function, is motivated by the potential of plasma reduction or depletion to mitigate various transfusion-related adverse events. This report considers the electrolytic composition of previously described platelet additive solutions, in order to draw general conclusions about what is required for platelet function and longevity. The optimal concentrations of Na(+) and Cl(-) are 69-115 mM. The presence of both K(+) and Mg(2+) in platelet suspension at nearly physiological concentrations (3-5mM and 1.5-3mM, respectively) is indispensable for good preservation capacity because both electrolytes are required to prevent platelet activation. In contrast to K(+) and Mg(2+), Ca(2+) may not be important because no free Ca(2+) is available in M-sol, which showed excellent platelet preservation capacity at less than 5% plasma concentration. The importance of bicarbonate (approximately 40 mM) can be recognized when the platelets are suspended in additive solution under less than 5% residual plasma concentration.

  2. Nanostructured Polymer Electrolytes

    NASA Astrophysics Data System (ADS)

    Odusanya, Omolola; Singh, Mohit; Balsara, Nitash

    2006-03-01

    We present results on work on polystyrene-b-polyethyleneoxide copolymer electrolyte membranes. The volume fraction of the ethylene oxide block is 0.38 and molecular weight of each block is 36 kg/mol and 25 kg/mol respectively for the polystyrene and ethyleneoxide blocks. These electrolytes were made by doping with lithium bis(trifluoromethylsulfonyl)imide salt with the ratio of Li ion / ethylene oxide units ranging from 0.02 to 0.1. The salt/polymer samples were pressed into 1.0mm thick and 4.0 mm ID pellets in an air-free environment and measurements were made from 80^oC to 120^oC. Transmission Electron Microscopy and Small Angle X-ray Scattering experiment results indicate that our samples have a perforated hexagonal morphology. Conductivity results using AC impedance spectroscopy show that we are able to achieve values of ˜ 0.0001 S/cm, well within the theoretical upper limit expected for these samples while maintaining a high mechanical integrity of about 0.1GPa as determined from rheology. Achieving the combination of high conductivity with mechanical strength, which we observe in our results, has been a major problem in the battery research community.

  3. Electrolytes - Technology review

    SciTech Connect

    Meutzner, Falk; Ureña de Vivanco, Mateo

    2014-06-16

    Safety, lifetime, energy density, and costs are the key factors for battery development. This generates the need for improved cell chemistries and new, advanced battery materials. The components of an electrolyte are the solvent, in which a conducting salt and additives are dissolved. Each of them plays a specific role in the overall mechanism of a cell: the solvent provides the host medium for ionic conductivity, which originates in the conductive salt. Furthermore, additives can be used to optimize safety, performance, and cyclability. By understanding the tasks of the individual components and their optimum conditions of operation, the functionality of cells can be improved from a holistic point of view. This paper will present the most important technological features and requirements for electrolytes in lithium-ion batteries. The state-of-the-art chemistry of each component is presented, as well as different approaches for their modification. Finally, a comparison of Li-cells with lithium-based technologies currently under development is conducted.

  4. A switchable pH-differential unitized regenerative fuel cell with high performance

    NASA Astrophysics Data System (ADS)

    Lu, Xu; Xuan, Jin; Leung, Dennis Y. C.; Zou, Haiyang; Li, Jiantao; Wang, Hailiang; Wang, Huizhi

    2016-05-01

    Regenerative fuel cells are a potential candidate for future energy storage, but their applications are limited by the high cost and poor round-trip efficiency. Here we present a switchable pH-differential unitized regenerative fuel cell capable of addressing both the obstacles. Relying on a membraneless laminar flow-based design, pH environments in the cell are optimized independently for different electrode reactions and are switchable together with the cell process to ensure always favorable thermodynamics for each electrode reaction. Benefiting from the thermodynamic advantages of the switchable pH-differential arrangement, the cell allows water electrolysis at a voltage of 0.57 V, and a fuel cell open circuit voltage of 1.89 V, rendering round-trip efficiencies up to 74%. Under room conditions, operating the cell in fuel cell mode yields a power density of 1.3 W cm-2, which is the highest performance to date for laminar flow-based cells and is comparable to state-of-the-art polymer electrolyte membrane fuel cells.

  5. Thin film polymeric gel electrolytes

    DOEpatents

    Derzon, Dora K.; Arnold, Jr., Charles; Delnick, Frank M.

    1996-01-01

    Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

  6. Thin film polymeric gel electrolytes

    DOEpatents

    Derzon, D.K.; Arnold, C. Jr.; Delnick, F.M.

    1996-12-31

    Novel hybrid thin film electrolytes, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities {approx_equal}10{sup {minus}3}{Omega}{sup {minus}1} cm{sup {minus}1} are useful as electrolytes for rechargeable lithium batteries. 1 fig.

  7. Application of Organic Solid Electrolytes

    NASA Technical Reports Server (NTRS)

    Sekido, S.

    1982-01-01

    If ions are considered to be solid material which transport electric charges, polymer materials can then be considered as organic solid electrolytes. The role of these electrolytes is discussed for (1) ion concentration sensors; (2) batteries using lithium as the cathode and a charge complex of organic material and iodine in the anode; and (3) elements applying electrical double layer capability.

  8. Gelled Electrolytes For Lithium Batteries

    NASA Technical Reports Server (NTRS)

    Nagasubramanian, Ganesan; Attia, Alan; Halpert, Gerald

    1993-01-01

    Gelled polymer electrolyte consists of polyacrylonitrile (PAN), LiBF4, and propylene carbonate (PC). Thin films of electrolyte found to exhibit stable bulk conductivities of order of 10 to the negative 3rd power S/cm at room temperature. Used in thinfilm rechargeable lithium batteries having energy densities near 150 W h/kg.

  9. Electrolyte treatment for aluminum reduction

    DOEpatents

    Brown, Craig W.; Brooks, Richard J.; Frizzle, Patrick B.; Juric, Drago D.

    2002-01-01

    A method of treating an electrolyte for use in the electrolytic reduction of alumina to aluminum employing an anode and a cathode, the alumina dissolved in the electrolyte, the treating improving wetting of the cathode with molten aluminum during electrolysis. The method comprises the steps of providing a molten electrolyte comprised of ALF.sub.3 and at least one salt selected from the group consisting of NaF, KF and LiF, and treating the electrolyte by providing therein 0.004 to 0.2 wt. % of a transition metal or transition metal compound for improved wettability of the cathode with molten aluminum during subsequent electrolysis to reduce alumina to aluminum.

  10. Electrolytic decontamination of conductive materials

    SciTech Connect

    Nelson, T.O.; Campbell, G.M.; Parker, J.L.; Getty, R.H.; Hergert, T.R.; Lindahl, K.A.; Peppers, L.G.

    1993-10-01

    Using the electrolytic method, the authors have demonstrated removal of Pu from contaminated conductive material. At EG&G Rocky Flats, they electrolytically decontaminated stainless steel. Results from this work show removal of fixed contamination, including the following geometries: planar, large radius, bolt holes, glove ports, and protruding studs. More specifically, fixed contamination was reduced from levels ranging > 1,000,000 counts per minute (cpm) down to levels ranging from 1,500 to < 250 cpm with the electrolytic method. More recently, the electrolytic work has continued at LANL as a joint project with EG&G. Impressively, electrolytic decontamination experiments on removal of Pu from oralloy coupons have shown decreases in swipable contamination that initially ranged from 500,000 to 1,500,000 disintegrations per minute (dpm) down to 0--2 dpm.

  11. Scaffolds in regenerative endodontics: A review

    PubMed Central

    Gathani, Kinjal M.; Raghavendra, Srinidhi Surya

    2016-01-01

    Root canal therapy has enabled us to save numerous teeth over the years. The most desired outcome of endodontic treatment would be when diseased or nonvital pulp is replaced with healthy pulp tissue that would revitalize the teeth through regenerative endodontics. ‘A search was conducted using the Pubmed and MEDLINE databases for articles with the criteria ‘Platelet rich plasma’, ‘Platelet rich fibrin’, ‘Stem cells’, ‘Natural and artificial scaffolds’ from 1982–2015’. Tissues are organized as three-dimensional structures, and appropriate scaffolding is necessary to provide a spatially correct position of cell location and regulate differentiation, proliferation, or metabolism of the stem cells. Extracellular matrix molecules control the differentiation of stem cells, and an appropriate scaffold might selectively bind and localize cells, contain growth factors, and undergo biodegradation over time. Different scaffolds facilitate the regeneration of different tissues. To ensure a successful regenerative procedure, it is essential to have a thorough and precise knowledge about the suitable scaffold for the required tissue. This article gives a review on the different scaffolds providing an insight into the new developmental approaches on the horizon. PMID:27857762

  12. Translational science in disinfection for regenerative endodontics.

    PubMed

    Diogenes, Anibal R; Ruparel, Nikita B; Teixeira, Fabricio B; Hargreaves, Kenneth M

    2014-04-01

    The endodontic management of permanent immature teeth is fraught with challenges. Although treatment modalities for vital pulp therapy in these teeth provide long-term favorable outcome, the outcomes from the treatment of pulp necrosis and apical periodontitis are significantly less predictable. Immature teeth diagnosed with pulp necrosis have been traditionally treated with apexification or apexogenesis approaches. Unfortunately, these treatments provide little to no benefit in promoting continued root development. Regenerative endodontic procedures have emerged as an important alternative in treating teeth with otherwise questionable long-term prognosis because of thin, fragile dentinal walls and a lack of immunocompetency. These procedures rely heavily on root canal chemical disinfection of the root canal system. Traditionally, irrigants and medicaments have been chosen for their maximum antimicrobial effect without consideration for their effects on stem cells and the dentinal microenvironment. Translational research has been crucial to provide evidence for treatment modifications that aim to increase favorable outcome while steering away from common pitfalls in the currently used protocols. In this review, recent advances learned from translational research related to disinfection in regenerative endodontics are presented and discussed. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. PRMT7 Preserves Satellite Cell Regenerative Capacity.

    PubMed

    Blanc, Roméo Sébastien; Vogel, Gillian; Chen, Taiping; Crist, Colin; Richard, Stéphane

    2016-02-16

    Regeneration of skeletal muscle requires the continued presence of quiescent muscle stem cells (satellite cells), which become activated in response to injury. Here, we report that whole-body protein arginine methyltransferase PRMT7(-/-) adult mice and mice conditionally lacking PRMT7 in satellite cells using Pax7-CreERT2 both display a significant reduction in satellite cell function, leading to defects in regenerative capacity upon muscle injury. We show that PRMT7 is preferentially expressed in activated satellite cells and, interestingly, PRMT7-deficient satellite cells undergo cell-cycle arrest and premature cellular senescence. These defects underlie poor satellite cell stem cell capacity to regenerate muscle and self-renew after injury. PRMT7-deficient satellite cells express elevated levels of the CDK inhibitor p21CIP1 and low levels of its repressor, DNMT3b. Restoration of DNMT3b in PRMT7-deficient cells rescues PRMT7-mediated senescence. Our findings define PRMT7 as a regulator of the DNMT3b/p21 axis required to maintain muscle stem cell regenerative capacity.

  14. Erich Regener - a forgotten cosmic ray pioneer

    NASA Astrophysics Data System (ADS)

    Carlson, Per; Watson, Alan

    2013-04-01

    In the 1930s the German physicist Erich Regener (1881-1955), did important work on the measurement of the rate production of ionisation in the atmosphere and deep under-water. He discovered, along with one of his students, Georg Pfotzer, the altitude at which the production of ionisation in the atmosphere reaches a maximum, often and misleadingly called the Pfotzer maximum. He was one of the first to estimate the energy density of cosmic rays, an estimate used by Baade and Zwicky to postulate that supernovae might be the source of cosmic rays. Yet Regener's name is little known largely because he was forced to take early retirement by the National Socialists in 1937 as his wife had Jewish ancestors. In this paper we review his work on cosmic rays and the subsequent influence that he had on the subject through his son, his son-in-law, his grandson and his students. He was nominated for the Nobel Prize in Physics by Schroedinger in 1938. He died in 1955 at the age of 73.

  15. Multiple excitation regenerative amplifier inertial confinement system

    DOEpatents

    George, Victor E. [Livermore, CA; Haas, Roger A. [Pleasanton, CA; Krupke, William F. [Pleasanton, CA; Schlitt, Leland G. [Livermore, CA

    1980-05-27

    The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation.

  16. Multiple excitation regenerative amplifier inertial confinement system

    DOEpatents

    George, V.E.; Haas, R.A.; Krupke, W.F.; Schlitt, L.G.

    1980-05-27

    The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation. 11 figs.

  17. Scaffolds in regenerative endodontics: A review.

    PubMed

    Gathani, Kinjal M; Raghavendra, Srinidhi Surya

    2016-09-01

    Root canal therapy has enabled us to save numerous teeth over the years. The most desired outcome of endodontic treatment would be when diseased or nonvital pulp is replaced with healthy pulp tissue that would revitalize the teeth through regenerative endodontics. 'A search was conducted using the Pubmed and MEDLINE databases for articles with the criteria 'Platelet rich plasma', 'Platelet rich fibrin', 'Stem cells', 'Natural and artificial scaffolds' from 1982-2015'. Tissues are organized as three-dimensional structures, and appropriate scaffolding is necessary to provide a spatially correct position of cell location and regulate differentiation, proliferation, or metabolism of the stem cells. Extracellular matrix molecules control the differentiation of stem cells, and an appropriate scaffold might selectively bind and localize cells, contain growth factors, and undergo biodegradation over time. Different scaffolds facilitate the regeneration of different tissues. To ensure a successful regenerative procedure, it is essential to have a thorough and precise knowledge about the suitable scaffold for the required tissue. This article gives a review on the different scaffolds providing an insight into the new developmental approaches on the horizon.

  18. Analysis of Regen Cooling in Rocket Combustors

    NASA Technical Reports Server (NTRS)

    Harper, Brent (Technical Monitor); Merkle, C. L.; Li, D.; Sankaran, V.

    2004-01-01

    The use of detailed CFD modeling for the description of cooling in rocket chambers is discussed. The overall analysis includes a complete three-dimensional analysis of the flow in the regenerative cooling passages, conjugate heat transfer in the combustor walls, and the effects of film cooling on the inside chamber. The results in the present paper omit the effects of film cooling and include only regen cooling and the companion conjugate heat transfer. The hot combustion gases are replaced by a constant temperature wall boundary condition. Load balancing for parallel cluster computations is ensured by using single-block unstructured grids for both fluids and solids, and by using a 'multiple physical zones' to account for differences in the number of equations. Validation of the method is achieved by comparing simple two-dimensional solutions with analytical results. Representative results for cooling passages are presents showing the effects of heat conduction in the copper walls with tube aspect ratios of 1.5:l.

  19. Engineering growth factors for regenerative medicine applications.

    SciTech Connect

    Mitchell, Aaron C.; Briquez, Priscilla S.; Hubbell, Jeffrey A.; Cochran, Jennifer R.

    2016-01-15

    Growth factors are important morphogenetic proteins that instruct cell behavior and guide tissue repair and renewal. Although their therapeutic potential holds great promise in regenerative medicine applications, translation of growth factors into clinical treatments has been hindered by limitations including poor protein stability, low recombinant expression yield, and suboptimal efficacy. This review highlights current tools, technologies, and approaches to design integrated and effective growth factor-based therapies for regenerative medicine applications. The first section describes rational and combinatorial protein engineering approaches that have been utilized to improve growth factor stability, expression yield, biodistribution, and serum half-life, or alter their cell trafficking behavior or receptor binding affinity. The second section highlights elegant biomaterial-based systems, inspired by the natural extracellular matrix milieu, that have been developed for effective spatial and temporal delivery of growth factors to cell surface receptors. Although appearing distinct, these two approaches are highly complementary and involve principles of molecular design and engineering to be considered in parallel when developing optimal materials for clinical applications.

  20. Bioethical aspects of regenerative and reproductive medicine.

    PubMed

    Yoshimura, Yasunori

    2006-05-01

    The birth announced in 1997 of Dolly, the lamb cloned from the somatic mammary cells of an adult ewe, and the discovery of human embryonic stem cells in 1998 have been the most exciting developments in the biological sciences in the past decade. Reproductive somatic cell nuclear transfer (SCNT) in additional species has been inefficient in that relatively few births, harmful side effects and high fetal and neonatal death rates have resulted from many attempts. Ongoing debates about the ethics of reproductive SCNT have revealed that some researchers regard human reproductive SCNT as morally unacceptable in all circumstances, others see merit in reproductive SCNT in certain circumstances and others await more information before making judgment about the ethical status of the procedure. Regenerative medicine and emerging biotechnologies started to revolutionize the practice of medicine. Advances in stem cell biology, including embryonic and postnatal somatic stem cells, have made the prospect of tissue regeneration a potential reality. Mammal cloning experiments have provided new impetus to the prospect of regenerative medicine through stem cell research. The procedure of SCNT could be used to create the raw material to replace defective or senescent tissue as a natural extension of the biology of stem cells. Researchers working in reproductive medicine should consider the potential hope given to many patients against the requisite and ethically contentious creation of human blastocysts for therapeutic intent.

  1. Electrolytes and thermoregulation

    NASA Technical Reports Server (NTRS)

    Nielsen, B.; Greenleaf, J. E.

    1977-01-01

    The influence of ions on temperature is studied for cases where the changes in ionic concentrations are induced by direct infusion or injection of electrolyte solutions into the cerebral ventricles or into specific areas of brain tissue; intravenous infusion or injection; eating food or drinking solutions of different ionic composition; and heat or exercise dehydration. It is shown that introduction of Na(+) and Ca(++) into the cerebral ventricles or into the venous system affects temperature regulation. It appears that the specific action of these ions is different from their osmotic effects. It is unlikely that their action is localized to the thermoregulatory centers in the brain. The infusion experiments demonstrate that the changes in sodium balance occurring during exercise and heat stress are large enough to affect sweat gland function and vasomotor activity.

  2. Electrolytes and thermoregulation

    NASA Technical Reports Server (NTRS)

    Nielsen, B.; Greenleaf, J. E.

    1977-01-01

    The influence of ions on temperature is studied for cases where the changes in ionic concentrations are induced by direct infusion or injection of electrolyte solutions into the cerebral ventricles or into specific areas of brain tissue; intravenous infusion or injection; eating food or drinking solutions of different ionic composition; and heat or exercise dehydration. It is shown that introduction of Na(+) and Ca(++) into the cerebral ventricles or into the venous system affects temperature regulation. It appears that the specific action of these ions is different from their osmotic effects. It is unlikely that their action is localized to the thermoregulatory centers in the brain. The infusion experiments demonstrate that the changes in sodium balance occurring during exercise and heat stress are large enough to affect sweat gland function and vasomotor activity.

  3. Polymeric electrolytic hygrometer

    NASA Technical Reports Server (NTRS)

    Lawson, D. D. (Inventor)

    1978-01-01

    An improved flow-through electrolytic hygrometer is described which utilizes a long lasting oxidation-resistant, hollow fiber formed from persulfonic acid substituted polytetrafluoroethylene having closely spaced noble metal electrodes in contact with the inner and outer surfaces of the fiber. The fiber is disposed within a chamber so that the moisture-bearing gas passes in contact with at least one surface of the fiber. The electrodes are connected in series to a dc voltage supply and an ammeter. As the gas passes through the chamber, moisture absorbed into the wall of the fiber is electrolyzed to hydrogen and oxygen by the closely spaced electrodes. The amount of electricity required for electrolysis is proportional to the absorbed moisture and is observed on the ammeter.

  4. Stem cells: intellectual property issues in regenerative medicine.

    PubMed

    Zachariades, Nicholas A

    2013-12-01

    The topic of stem cells for use in regenerative medicine, especially embryonic stem cells, inspires much debate, discussion, and outrage as it slices through the very core moral values of society. These social and moral issues have, in turn, resulted in government policies that have influenced the study of stem cells in regenerative medicine.

  5. Regenerative medicine. Opportunities and challenges: a brief overview.

    PubMed

    Polak, Dame Julia

    2010-12-06

    Regenerative medicine is a new multi-disciplinary field aiming at the repair or replacement of disease body parts. The field is progressing at an unprecedented pace and although the opportunities are immense, many hurdles lie ahead. This brief review analyses the opportunities and challenges faced by regenerative medicine.

  6. Improved Round Trip Efficiency for Regenerative Fuel Cell Systems

    DTIC Science & Technology

    2011-04-04

    advanced membrane materials that enable higher efficiency electrolysis , substantially improving the practical energy density for regenerative fuel cell... electrolysis system for recharging the reactants, and reactant storage. These water- based energy storage systems have been shown to perform...catalyst materials will enable higher efficiency electrolysis , substantially improving the practical energy density for regenerative fuel cell applications

  7. State of the art: stem cells in equine regenerative medicine.

    PubMed

    Lopez, M J; Jarazo, J

    2015-03-01

    According to Greek mythology, Prometheus' liver grew back nightly after it was removed each day by an eagle as punishment for giving mankind fire. Hence, contrary to popular belief, the concept of tissue and organ regeneration is not new. In the early 20th century, cell culture and ex vivo organ preservation studies by Alexis Carrel, some with famed aviator Charles Lindbergh, established a foundation for much of modern regenerative medicine. While early beliefs and discoveries foreshadowed significant accomplishments in regenerative medicine, advances in knowledge within numerous scientific disciplines, as well as nano- and micromolecular level imaging and detection technologies, have contributed to explosive advances over the last 20 years. Virtually limitless preparations, combinations and applications of the 3 major components of regenerative medicine, namely cells, biomaterials and bioactive molecules, have created a new paradigm of future therapeutic options for most species. It is increasingly clear, however, that despite significant parallels among and within species, there is no 'one-size-fits-all' regenerative therapy. Likewise, a panacea has yet to be discovered that completely reverses the consequences of time, trauma and disease. Nonetheless, there is no question that the promise and potential of regenerative medicine have forever altered medical practices. The horse is a relative newcomer to regenerative medicine applications, yet there is already a large body of work to incorporate novel regenerative therapies into standard care. This review focuses on the current state and potential future of stem cells in equine regenerative medicine.

  8. Electrolyte paste for molten carbonate fuel cells

    SciTech Connect

    Bregoli, Lawrance J.; Pearson, Mark L.

    1995-01-01

    The electrolyte matrix and electrolyte reservoir plates in a molten carbonate fuel cell power plant stack are filled with electrolyte by applying a paste of dry electrolyte powder entrained in a dissipatable carrier to the reactant flow channels in the current collector plate. The stack plates are preformed and solidified to final operating condition so that they are self sustaining and can be disposed one atop the other to form the power plant stack. Packing the reactant flow channels with the electrolyte paste allows the use of thinner electrode plates, particularly on the anode side of the cells. The use of the packed electrolyte paste provides sufficient electrolyte to fill the matrix and to entrain excess electrolyte in the electrode plates, which also serve as excess electrolyte reservoirs. When the stack is heated up to operating temperatures, the electrolyte in the paste melts, the carrier vaporizes, or chemically decomposes, and the melted electrolyte is absorbed into the matrix and electrode plates.

  9. Stem Cells Applications in Regenerative Medicine and Disease Therapeutics

    PubMed Central

    2016-01-01

    Regenerative medicine, the most recent and emerging branch of medical science, deals with functional restoration of tissues or organs for the patient suffering from severe injuries or chronic disease. The spectacular progress in the field of stem cell research has laid the foundation for cell based therapies of disease which cannot be cured by conventional medicines. The indefinite self-renewal and potential to differentiate into other types of cells represent stem cells as frontiers of regenerative medicine. The transdifferentiating potential of stem cells varies with source and according to that regenerative applications also change. Advancements in gene editing and tissue engineering technology have endorsed the ex vivo remodelling of stem cells grown into 3D organoids and tissue structures for personalized applications. This review outlines the most recent advancement in transplantation and tissue engineering technologies of ESCs, TSPSCs, MSCs, UCSCs, BMSCs, and iPSCs in regenerative medicine. Additionally, this review also discusses stem cells regenerative application in wildlife conservation. PMID:27516776

  10. Stem Cells Applications in Regenerative Medicine and Disease Therapeutics.

    PubMed

    Mahla, Ranjeet Singh

    2016-01-01

    Regenerative medicine, the most recent and emerging branch of medical science, deals with functional restoration of tissues or organs for the patient suffering from severe injuries or chronic disease. The spectacular progress in the field of stem cell research has laid the foundation for cell based therapies of disease which cannot be cured by conventional medicines. The indefinite self-renewal and potential to differentiate into other types of cells represent stem cells as frontiers of regenerative medicine. The transdifferentiating potential of stem cells varies with source and according to that regenerative applications also change. Advancements in gene editing and tissue engineering technology have endorsed the ex vivo remodelling of stem cells grown into 3D organoids and tissue structures for personalized applications. This review outlines the most recent advancement in transplantation and tissue engineering technologies of ESCs, TSPSCs, MSCs, UCSCs, BMSCs, and iPSCs in regenerative medicine. Additionally, this review also discusses stem cells regenerative application in wildlife conservation.

  11. Evaluation strategy of regenerative braking energy for supercapacitor vehicle.

    PubMed

    Zou, Zhongyue; Cao, Junyi; Cao, Binggang; Chen, Wen

    2015-03-01

    In order to improve the efficiency of energy conversion and increase the driving range of electric vehicles, the regenerative energy captured during braking process is stored in the energy storage devices and then will be re-used. Due to the high power density of supercapacitors, they are employed to withstand high current in the short time and essentially capture more regenerative energy. The measuring methods for regenerative energy should be investigated to estimate the energy conversion efficiency and performance of electric vehicles. Based on the analysis of the regenerative braking energy system of a supercapacitor vehicle, an evaluation system for energy recovery in the braking process is established using USB portable data-acquisition devices. Experiments under various braking conditions are carried out. The results verify the higher efficiency of energy regeneration system using supercapacitors and the effectiveness of the proposed measurement method. It is also demonstrated that the maximum regenerative energy conversion efficiency can reach to 88%.

  12. Enhancing low-grade thermal energy recovery in a thermally regenerative ammonia battery using elevated temperatures.

    PubMed

    Zhang, Fang; LaBarge, Nicole; Yang, Wulin; Liu, Jia; Logan, Bruce E

    2015-03-01

    A thermally regenerative ammonia battery (TRAB) is a new approach for converting low-grade thermal energy into electricity by using an ammonia electrolyte and copper electrodes. TRAB operation at 72 °C produced a power density of 236 ± 8 Wm(-2), with a linear decrease in power to 95 ± 5 Wm(-2) at 23 °C. The improved power at higher temperatures was due to reduced electrode overpotentials and more favorable thermodynamics for the anode reaction (copper oxidation). The energy density varied with temperature and discharge rates, with a maximum of 650 Wh m(-3) at a discharge energy efficiency of 54% and a temperature of 37 °C. The energy efficiency calculated with chemical process simulation software indicated a Carnot-based efficiency of up to 13% and an overall thermal energy recovery of 0.5%. It should be possible to substantially improve these energy recoveries through optimization of electrolyte concentrations and by using improved ion-selective membranes and energy recovery systems such as heat exchangers.

  13. Thermal System Modeling for Lunar and Martian Surface Regenerative Fuel Cell Systems

    NASA Technical Reports Server (NTRS)

    Gilligan, Ryan Patrick; Smith, Phillip James; Jakupca, Ian Joseph; Bennett, William Raymond; Guzik, Monica Christine; Fincannon, Homer J.

    2017-01-01

    The Advanced Exploration Systems (AES) Advanced Modular Power Systems (AMPS) Project is investigating different power systems for various lunar and Martian mission concepts. The AMPS Fuel Cell (FC) team has created two system-level models to evaluate the performance of regenerative fuel cell (RFC) systems employing different fuel cell chemistries. Proton Exchange Membrane fuel cells PEMFCs contain a polymer electrolyte membrane that separates the hydrogen and oxygen cavities and conducts hydrogen cations (protons) across the cell. Solid Oxide fuel cells (SOFCs) operate at high temperatures, using a zirconia-based solid ceramic electrolyte to conduct oxygen anions across the cell. The purpose of the modeling effort is to down select one fuel cell chemistry for a more detailed design effort. Figures of merit include the system mass, volume, round trip efficiency, and electrolyzer charge power required. PEMFCs operate at around 60 degrees Celsius versus SOFCs which operate at temperatures greater than 700 degrees Celsius. Due to the drastically different operating temperatures of the two chemistries the thermal control systems (TCS) differ. The PEM TCS is less complex and is characterized by a single pump cooling loop that uses deionized water coolant and rejects heat generated by the system to the environment via a radiator. The solid oxide TCS has its own unique challenges including the requirement to reject high quality heat and to condense the steam produced in the reaction. This paper discusses the modeling of thermal control systems for an extraterrestrial RFC that utilizes either a PEM or solid oxide fuel cell.

  14. Electrolyte composition for electrochemical cell

    DOEpatents

    Vissers, Donald R.; Tomczuk, Zygmunt; Anderson, Karl E.; Roche, Michael F.

    1979-01-01

    A high-temperature, secondary electrochemical cell that employs FeS as the positive electrode reactant and lithium or lithium alloy as the negative electrode reactant includes an improved electrolyte composition. The electrolyte comprises about 60-70 mole percent LiCl and 30-40 percent mole percent KCl which includes LiCl in excess of the eutectic composition. The use of this electrolyte suppresses formation of the J phase and thereby improves the utilization of positive electrode active material during cell cycling.

  15. Lithium ion conducting ionic electrolytes

    DOEpatents

    Angell, C.A.; Xu, K.; Liu, C.

    1996-01-16

    A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100 C or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors. 4 figs.

  16. Lithium ion conducting ionic electrolytes

    DOEpatents

    Angell, C. Austen; Xu, Kang; Liu, Changle

    1996-01-01

    A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors.

  17. Organic electrolytes for sodium batteries

    NASA Astrophysics Data System (ADS)

    Vestergaard, B.

    1992-09-01

    A summary of earlier given status reports in connection with the project on organic electrolytes for sodium batteries is presented. The aim of the investigations was to develop new room temperature molten salts electrolytes mainly with radical substituted heterocyclic organic chlorides mixed with aluminum chloride. The new electrolytes should have an ionic conductivity comparable with MEIC1:AlCl3 or better. A computer model program MOPAC (Molecular Orbital Package) was to be included to calculate theoretically reduction potentials for a variety of organic cations. Furthermore, MOPAC could be utilized to predict the electron densities, and then give a prediction of the stability of the organic cation.

  18. Photopolymerized Electrolytes For Electrochromic Devices

    NASA Technical Reports Server (NTRS)

    Cogan, Stuart; Rauh, R. David

    1994-01-01

    Thin ion-conducting electrolyte films for use in electrochromic devices now fabricated relatively easily and quickly with any of class of improved formulations containing ultraviolet-polymerizable components. Formulations are liquids in their monomeric forms and self-supporting, transparent solids in their polymeric forms. Thin solid electrolytes form quickly and easily between electrode-bearing substrates. Film thus polymerized acts not only as solid electrolyte but also as glue holding laminate together: feature simplifies fabrication by reducing need for sealants and additional mechanical supports.

  19. Photopolymerized Electrolytes For Electrochromic Devices

    NASA Technical Reports Server (NTRS)

    Cogan, Stuart; Rauh, R. David

    1994-01-01

    Thin ion-conducting electrolyte films for use in electrochromic devices now fabricated relatively easily and quickly with any of class of improved formulations containing ultraviolet-polymerizable components. Formulations are liquids in their monomeric forms and self-supporting, transparent solids in their polymeric forms. Thin solid electrolytes form quickly and easily between electrode-bearing substrates. Film thus polymerized acts not only as solid electrolyte but also as glue holding laminate together: feature simplifies fabrication by reducing need for sealants and additional mechanical supports.

  20. Static regenerative fuel cell system for use in space

    SciTech Connect

    Levy, A.H.; VanDine, L.L.; Trocciola, J.C.

    1989-06-13

    This patent describes a repeating component within an electrochemical cell stack comprising: (a) means forming a flat fuel cell electrolyte matrix; (b) a flat porous fuel cell electrolyte reservoir plate batting the fuel cell electrolyte matrix and operable to draw and store product water from the fuel cell electrolyte matrix when the stack is operating in a fuel cell mode; (c) a flat porous electrolysis cell electrolyte reservoir plate adjacent to the fuel cell electrolyte reservoir plate; (d) means forming a flat electrolysis cell electrolyte matrix abutting the electrolysis cell electrolyte reservoir plate, the latter being operable to draw water from the fuel cell electrolyte reservoir plate to the electrolysis cell electrolyte matrix for consumption when the stack is operating in an electrolysis cell mode; (e) a first formed metallic separator plate adjacent to the fuel cell electrolyte matrix; (f) a first flat current conductor plate adjacent to and in contact with the first formed plate; (g) a first insulating sheet adjacent the first conductor plate; (h) a second formed metallic separator plate adjacent to the electrolysis cell electrolyte matrix; (i) a second flat current conductor plate adjacent to and in contact with the second formed plate; (j) a second insulating sheet adjacent the second conductor plate; and (k) a flat cooling plate adjacent at least one of the insulating sheets.

  1. Ru xCr ySe z electrocatalyst for oxygen reduction in a polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Suárez-Alcántara, K.; Rodríguez-Castellanos, A.; Dante, R.; Solorza-Feria, O.

    Powder of Ru xCr ySe z electrocatalyst was prepared from decarbonylation of the transition-metal carbonyl compounds in an organic solution containing dissolved selenium. The synthesized catalyst was characterized by FT-IR, X-ray diffraction (XRD), SEM and electrochemically. The powder catalyst presents high uniformity of cauliflower-like agglomerates of nanocrystalline particles embedded in an amorphous phase. The electrocatalysis of the oxygen reduction at this material on the ink-type electrode in acid electrolyte was studied by using the rotating disk electrode (RDE) technique. The Ru xCr ySe z catalyst presented attractive catalytic activity for the oxygen reduction reaction, ORR, in 0.5 M H 2SO 4. The Tafel slope for the ORR remains constant with temperature at -0.117 V dec -1 and the charge transfer coefficient increases in d α/d T = 1.8 × 10 -3, attributed to entropy turnover contribution similar to those reported on ruthenium-based selenide catalysts. The effect of temperature on the kinetics of ORR was analyzed and an apparent activation energy of 40.6 kJ mol -1 was determined. The performance achieved from the hydrogen-oxygen polymer electrolyte membrane fuel cell (PEMFC), with cathode of Ru xCr ySe z catalyst operating at different temperatures, was evaluated.

  2. Replication of the Apparent Excess Heat Effect in a Light Water-Potassium Carbonate-Nickel Electrolytic Cell

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.; Myers, Ira T.; Fralick, Gustave C.; Baldwin, Richard S.

    1996-01-01

    Replication of experiments claiming to demonstrate excess heat production in light water-Ni-K2CO3 electrolytic cells was found to produce an apparent excess heat of 11 W maximum, for 60 W electrical power into the cell. Power gains range from 1.06 to 1.68. The cell was operated at four different dc current levels plus one pulsed current run at 1 Hz, 10% duty cycle. The 28 liter cell used in these verification tests was on loan from a private corporation whose own tests with similar cells are documented to produce 50 W steady excess heat for a continuous period exceeding hundreds of days. The apparent excess heat can not be readily explained either in terms of nonlinearity of the cell's thermal conductance at a low temperature differential or by thermoelectric heat pumping. However, the present data do admit efficient recombination of dissolved hydrogen-oxygen as an ordinary explanation. Calorimetry methods and heat balance calculations for the verification tests are described. Considering the large magnitude of benefit if this effect is found to be a genuine new energy source, a more thorough investigation of evolved heat in the nickel-hydrogen system in both electrolytic and gaseous loading cells remains warranted.

  3. A regenerative approach towards mucosal fenestration closure.

    PubMed

    Gandi, Padma; Anumala, Naveen; Reddy, Amarender; Chandra, Rampalli Viswa

    2013-06-06

    Mucosal fenestration is an opening or an interstice through the oral mucosa. A lesion which occurs with greater frequency than generally realised, its occurrence is attributed to a myriad of causes. Mucogingival procedures including connective tissue grafts, free gingival grafts and lateral pedicle grafts are generally considered to be the treatment of choice in the closure of a mucosal fenestration. More often, these procedures are performed in conjunction with other procedures such as periradicular surgery and with bone grafts. However, the concomitant use of gingival grafts and bone grafts in mucosal fenestrations secondary to infections in sites exhibiting severe bone loss is highly debatable. In this article, we report two cases of mucosal fenestrations secondary to trauma and their management by regenerative periodontal surgery with the placement of guided tissue regeneration membrane and bone graft. The final outcome was a complete closure of the fenestration in both the cases.

  4. Carbohydrate engineered cells for regenerative medicine.

    PubMed

    Du, Jian; Yarema, Kevin J

    2010-06-15

    Carbohydrates are integral components of the stem cell niche on several levels; proteoglycans are a major constituent of the extracellular matrix (ECM) surrounding a cell, glycosoaminoglycans (GAGs) help link cells to the ECM and the neighboring cells, and small but informationally-rich oligosaccharides provide a "sugar code" that identifies each cell and provides it with unique functions. This article samples roles that glycans play in development and then describes how metabolic glycoengineering - a technique where monosaccharide analogs are introduced into the metabolic pathways of a cell and are biosynthetically incorporated into the glycocalyx - is overcoming many of the long-standing barriers to manipulating carbohydrates in living cells and tissues and is becoming an intriguing new tool for tissue engineering and regenerative medicine.

  5. Carbohydrate Engineered Cells for Regenerative Medicine

    PubMed Central

    Du, Jian; Yarema, Kevin J.

    2010-01-01

    Carbohydrates are integral components of the stem cell niche on several levels; proteoglycans are a major constituent of the extracellular matrix (ECM) surrounding a cell, glycosoaminoglycans (GAGs) help link cells to the ECM and the neighboring cells, and small but informationally-rich oligosaccharides provide a “sugar code” that identifies each cell and provides it with unique functions. This article samples roles that glycans play in development and then describes how metabolic glycoengineering – a technique where monosaccharide analogs are introduced into the metabolic pathways of a cell and are biosynthetically incorporated into the glycocalyx – is overcoming many of the long-standing barriers to manipulating carbohydrates in living cells and tissues and is becoming an intriguing new tool for tissue engineering and regenerative medicine. PMID:20117158

  6. Genetic engineering for skeletal regenerative medicine.

    PubMed

    Gersbach, Charles A; Phillips, Jennifer E; García, Andrés J

    2007-01-01

    The clinical challenges of skeletal regenerative medicine have motivated significant advances in cellular and tissue engineering in recent years. In particular, advances in molecular biology have provided the tools necessary for the design of gene-based strategies for skeletal tissue repair. Consequently, genetic engineering has emerged as a promising method to address the need for sustained and robust cellular differentiation and extracellular matrix production. As a result, gene therapy has been established as a conventional approach to enhance cellular activities for skeletal tissue repair. Recent literature clearly demonstrates that genetic engineering is a principal factor in constructing effective methods for tissue engineering approaches to bone, cartilage, and connective tissue regeneration. This review highlights this literature, including advances in the development of efficacious gene carriers, novel cell sources, successful delivery strategies, and optimal target genes. The current status of the field and the challenges impeding the clinical realization of these approaches are also discussed.

  7. A regenerative approach towards mucosal fenestration closure

    PubMed Central

    Gandi, Padma; Anumala, Naveen; Reddy, Amarender; Viswa Chandra, Rampalli

    2013-01-01

    Mucosal fenestration is an opening or an interstice through the oral mucosa. A lesion which occurs with greater frequency than generally realised, its occurrence is attributed to a myriad of causes. Mucogingival procedures including connective tissue grafts, free gingival grafts and lateral pedicle grafts are generally considered to be the treatment of choice in the closure of a mucosal fenestration. More often, these procedures are performed in conjunction with other procedures such as periradicular surgery and with bone grafts. However, the concomitant use of gingival grafts and bone grafts in mucosal fenestrations secondary to infections in sites exhibiting severe bone loss is highly debatable. In this article, we report two cases of mucosal fenestrations secondary to trauma and their management by regenerative periodontal surgery with the placement of guided tissue regeneration membrane and bone graft. The final outcome was a complete closure of the fenestration in both the cases. PMID:23749826

  8. Regenerative medicine: the emergence of an industry.

    PubMed

    Nerem, Robert M

    2010-12-06

    Over the last quarter of a century there has been an emergence of a tissue engineering industry, one that has now evolved into the broader area of regenerative medicine. There have been 'ups and downs' in this industry; however, it now appears to be on a track that may be described as 'back to the future'. The latest data indicate that for 2007 the private sector activity in the world for this industry is approaching $2.5 billion, with 167 companies/business units and more than 6000 employee full time equivalents. Although small compared with the medical device and also the pharmaceutical industries, these numbers are not insignificant. Thus, there is the indication that this industry, and the related technology, may still achieve its potential and address the needs of millions of patients worldwide, in particular those with needs that currently are unmet.

  9. Regenerative Medicine Strategies for Esophageal Repair

    PubMed Central

    Londono, Ricardo

    2015-01-01

    Pathologies that involve the structure and/or function of the esophagus can be life-threatening. The esophagus is a complex organ comprising nonredundant tissue that does not have the ability to regenerate. Currently available interventions for esophageal pathology have limited success and are typically associated with significant morbidity. Hence, there is currently an unmet clinical need for effective methods of esophageal repair. The present article presents a review of esophageal disease along with the anatomic and functional consequences of each pathologic process, the shortcomings associated with currently available therapies, and the latest advancements in the field of regenerative medicine with respect to strategies for esophageal repair from benchtop to bedside. PMID:25813694

  10. Liposomes in tissue engineering and regenerative medicine

    PubMed Central

    Monteiro, Nelson; Martins, Albino; Reis, Rui L.; Neves, Nuno M.

    2014-01-01

    Liposomes are vesicular structures made of lipids that are formed in aqueous solutions. Structurally, they resemble the lipid membrane of living cells. Therefore, they have been widely investigated, since the 1960s, as models to study the cell membrane, and as carriers for protection and/or delivery of bioactive agents. They have been used in different areas of research including vaccines, imaging, applications in cosmetics and tissue engineering. Tissue engineering is defined as a strategy for promoting the regeneration of tissues for the human body. This strategy may involve the coordinated application of defined cell types with structured biomaterial scaffolds to produce living structures. To create a new tissue, based on this strategy, a controlled stimulation of cultured cells is needed, through a systematic combination of bioactive agents and mechanical signals. In this review, we highlight the potential role of liposomes as a platform for the sustained and local delivery of bioactive agents for tissue engineering and regenerative medicine approaches. PMID:25401172

  11. Heart Valve Replacements with Regenerative Capacity

    PubMed Central

    Dijkman, Petra E.; Fioretta, Emanuela S.; Frese, Laura; Pasqualini, Francesco S.; Hoerstrup, Simon P.

    2016-01-01

    The incidence of severe valvular dysfunctions (e.g., stenosis and insufficiency) is increasing, leading to over 300,000 valves implanted worldwide yearly. Clinically used heart valve replacements lack the capacity to grow, inherently requiring repetitive and high-risk surgical interventions during childhood. The aim of this review is to present how different tissue engineering strategies can overcome these limitations, providing innovative valve replacements that proved to be able to integrate and remodel in pre-clinical experiments and to have promising results in clinical studies. Upon description of the different types of heart valve tissue engineering (e.g., in vitro, in situ, in vivo, and the pre-seeding approach) we focus on the clinical translation of this technology. In particular, we will deepen the many technical, clinical, and regulatory aspects that need to be solved to endure the clinical adaptation and the commercialization of these promising regenerative valves. PMID:27721704

  12. Regenerative medicine: implications for craniofacial surgery.

    PubMed

    Schantz, Jan-Thorsten; Machens, Hans-Günther; Schilling, Arndt F; Teoh, Swee-Hin

    2012-03-01

    Craniofacial reconstruction of cases with complex anatomy challenges surgeons. The recently emerging field of tissue engineering and regenerative medicine has resulted in a variety of novel therapeutic concepts particularly in the craniofacial area. However, researchers still face significant problems when translating scientific concepts from the bench to the bedside. Reconstruction procedures depend on sustainability, aesthetic outcome, and functionality. Tissue engineering approaches yield powerful tools for long-term satisfying results enabling customized reconstruction and supporting natural healing processes. In conclusion, further advances of tissue-engineered reconstruction need multidisciplinary research to create complex tissue structures and make satisfactory outcomes clinically achievable for most patients. This review highlights clinical advances in the field and gives an overview about current scientific concepts.

  13. Regenerative medicine: the emergence of an industry

    PubMed Central

    Nerem, Robert M.

    2010-01-01

    Over the last quarter of a century there has been an emergence of a tissue engineering industry, one that has now evolved into the broader area of regenerative medicine. There have been ‘ups and downs’ in this industry; however, it now appears to be on a track that may be described as ‘back to the future’. The latest data indicate that for 2007 the private sector activity in the world for this industry is approaching $2.5 billion, with 167 companies/business units and more than 6000 employee full time equivalents. Although small compared with the medical device and also the pharmaceutical industries, these numbers are not insignificant. Thus, there is the indication that this industry, and the related technology, may still achieve its potential and address the needs of millions of patients worldwide, in particular those with needs that currently are unmet. PMID:20843840

  14. [Cell transplant and regenerative stem cell therapy].

    PubMed

    Prosper, F

    2008-01-01

    The derivation of the first human embryonic stem cell lines as well as the notion of the unexpected plasticity and potential of the adult stem cells has significantly impacted the biomedical research. Many of the tissues long believe to lack any regenerative capacity has demonstrated otherwise. Patients alike physicians expectations for treatment of incurable diseases have also fuelled this field and in occasions have led to unrealistic expectations. In the next pages I review some of the tissue specific stem cells that have been used either in preclinical models or even in clinical research. Despite the effort of numerous investigators, more questions that answers remain in the field of cell therapy and only careful and independent -not biased- research will allow us to translate some of this findings into clinical application.

  15. Regenerative system for a gas turbine

    SciTech Connect

    Wadsworth, W.

    1987-04-28

    A regenerative system is described for a gas turbine, wherein the turbine has a single shaft on which are mounted a compressor section and a work section, comprising: an air heater mounted adjacent the exit of the work section, the hot exit gas and pressurized air passing through passages formed in the air heater; combustor housings surrounding the compressor section, each containing a combustor mounted within it and extending coaxially thereof, each combustor having a transition section extending to the entrance to the work section; an annular connector housing extending between the combustor housing and the exit of the compressor section to carry the compressed air radially; an outer duct leading from the connector housing to one end of the air heater; and an inner duct attached to the other end of the air heater.

  16. The international translational regenerative medicine center.

    PubMed

    Alexis, Mardi de Veuve; Grinnemo, Karl-Henrik; Jove, Richard

    2012-11-01

    The International Translational Regenerative Medicine Center, an organizing sponsor of the World Stem Cell Summit 2012, is a global initiative established in 2011 by founding partners Karolinska Institutet (Stockholm, Sweden) and Beckman Research Institute at City of Hope (CA, USA) with a mission to facilitate the acceleration of translational research and medicine on a global scale. Karolinska Institutet, home of the Nobel Prize in Medicine or Physiology, is one of the most prestigious medical research institutions in the world. The Beckman Research Institute/City of Hope is ranked among the leading NIH-designated comprehensive cancer research and treatment institutions in the USA, has the largest academic GMP facility and advanced drug discovery capability, and is a pioneer in diabetes research and treatment.

  17. Why regenerative medicine needs an extracellular matrix.

    PubMed

    Prestwich, Glenn D; Healy, Kevin E

    2015-01-01

    Regenerative medicine is now coming of age. Many attempts at cell therapy have failed to show significant efficacy, and the umbrella term 'stem cell therapy' is perceived in some quarters as hype or just expensive and unnecessary medical tourism. Here we present a short editorial in three parts. First, we examine the importance of using a semisynthetic extracellular matrix (ECM) mimetic, or sECM, to deliver and retain therapeutic cells at the site of administration. Second, we describe one approach in which biophysical and biochemical properties are tailored to each tissue type, which we call "design for optimal functionality." Third, we describe an alternative approach to sECM design and implementation, called "design for simplicity," in which a deconstructed, minimalist sECM is employed and biology is allowed to perform the customization in situ. We opine that an sECM, whether minimal or instructive, is an essential contributor to improve the outcomes of cell-based therapies.

  18. New tools in regenerative medicine: gene therapy.

    PubMed

    Muñoz Ruiz, Miguel; Regueiro, José R

    2012-01-01

    Gene therapy aims to transfer genetic material into cells to provide them with new functions. A gene transfer agent has to be safe, capable of expressing the desired gene for a sustained period of time in a sufficiently large population of cells to produce a biological effect. Identifying a gene transfer tool that meets all of these criteria has proven to be a difficult objective. Viral and nonviral vectors, in vivo, ex vivo and in situ strategies co-exist at present, although ex vivo lenti-or retroviral vectors are presently the most popular.Natural stem cells (from embryonic, hematopoietic, mesenchymal, or adult tissues) or induced progenitor stem (iPS) cells can be modified by gene therapy for use in regenerative medicine. Among them, hematopoietic stem cells have shown clear clinical benefit, but iPS cells hold humongous potential with no ethical concerns.

  19. Heating system for regenerative coke oven batteries

    SciTech Connect

    Weber, H.; Morgenstern, M.; Stalherm, D.; Urbye, K.

    1984-02-14

    A heating system for regenerative coke oven batteries having a plurality of coke oven chambers separated by heating walls and a plurality of regenerators extending the length of the coke oven for preheating air and cooling hot waste gases comprises a plurality of spaced heating ducts extending upwardly in the heating walls which are grouped into two adjacent pairs of heating ducts. The ducts in each group of four heating ducts are separated by first and second binder walls with the first binder walls carrying one binder duct for supplying air and discharging hot waste to and from adjacent heat ducts in one of the pairs in the group. The second wall is either provided with no heating ducts or a pair of heating ducts. A horizontal channel connects the tops of all four heating ducts in each group and the lower end of each heating duct is provided with a rich gas supply nozzle.

  20. Rejuvenation: an integrated approach to regenerative medicine.

    PubMed

    Kang, Y James; Zheng, Lily

    2013-12-01

    The word "rejuvenate" found in the Merriam-Webster dictionary is (1) to make young or youthful again: give new vigor to, and (2) to restore to an original or new state. Regenerative medicine is the process of creating living, functional tissues to repair or replace tissue or organ function lost due to age, disease, damage, or congenital defects. To accomplish this, approaches including transplantation, tissue engineering, cell therapy, and gene therapy are brought into action. These all use exogenously prepared materials to forcefully mend the failed organ. The adaptation of the materials in the host and their integration into the organ are all uncertain. It is a common sense that tissue injury in the younger is easily repaired and the acute injury is healed better and faster. Why does the elder have a diminished capacity of self-repairing, or why does chronic injury cause the loss of the self-repairing capacity? There must be some critical elements that are involved in the repair process, but are suppressed in the elder or under the chronic injury condition. Rejuvenation of the self-repair mechanism would be an ideal solution for functional recovery of the failed organ. To achieve this, it would involve renewal of the injury signaling, reestablishment of the communication and transportation system, recruitment of the materials for repairing, regeneration of the failed organ, and rehabilitation of the renewed organ. It thus would require a comprehensive understanding of developmental biology and a development of new approaches to activate the critical players to rejuvenate the self-repair mechanism in the elder or under chronic injury condition. Efforts focusing on rejuvenation would expect an alternative, if not a better, accomplishment in the regenerative medicine.

  1. Regenerative Blower for EVA Suit Ventilation Fan

    NASA Technical Reports Server (NTRS)

    Paul, Heather; Izenson, Mike; Chen, Weibo

    2008-01-01

    Portable life support systems in future space suits will include a ventilation subsystem driven by a dedicated fan. This ventilation fan must meet challenging requirements for pressure rise, flow rate, efficiency, size, safety, and reliability. This paper describes research and development that showed the feasibility of a regenerative blower that is uniquely suited to meet these requirements. We proved feasibility through component tests, blower tests, and design analysis. Based on the requirements for the Constellation Space Suit ventilation fan, we designed the critical elements of the blower. We measured the effects of key design parameters on blower performance using separate effects tests, and used the results of these tests to design a regenerative blower that will meet the ventilation fan requirements. We assembled a proof-of-concept blower and measured its performance at low pressures that simulate a PLSS environment. We obtained head/flow performance curves over a range of operating speeds, identified the maximum efficiency point for the blower, and used these results to specify the design and operating conditions for the ventilation fan. We designed a compact motor that can drive the blower under all anticipated operating requirements and operate with high efficiency during normal operation. We identified materials for the blower that will enhance safety for operation in a lunar environment. We produced a solid model that illustrates the final design. The proof-of-concept blower produced the flow rate and pressure rise needed for the CSSS ventilation subsystem while running at 5400 rpm and consuming only 9 W of electric power and using a non-optimized, commercial motor and controller and inefficient bearings. Scaling the test results to a complete design shows that a lightweight, compact, reliable, and low power blower can meet the performance requirements for future PLSSs.

  2. Heat cascading regenerative sorption heat pump

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1995-01-01

    A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit (HTCC) powering a lower temperature physisorption circuit (LTPC) which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit (CHTC) is provided which contains a flowing heat transfer liquid (FHTL) in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC. Heat is regenerated within the LTPC by transferring heat from one compressor to another. In one embodiment the regeneration is performed by another CHTC containing another FHTL in thermal communication with each compressor. In another embodiment the HTCC powers a lower temperature ammonia water absorption circuit (LTAWAC) which contains a generator-absorber system containing the absorbent, and a condenser-evaporator-radiator system, operatively connected together. The absorbent is water or an absorbent aqueous solution. A CHTC is provided which contains a FHTL in thermal communication with the generator for cascading heat from the HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by transferring heat from the generator to the absorber. The chemical composition of the chemisorbent is different than the chemical composition of the physisorbent, and the absorbent. The chemical composition of the FHTL is different than the chemisorbent, the physisorbent, the absorbent, and ammonia.

  3. Power Management in Regenerative Life Support Systems

    NASA Technical Reports Server (NTRS)

    Crawford, Sekou; Pawlowski, Christopher; Finn, Cory; Mead, Susan C. (Technical Monitor)

    1999-01-01

    Effective management of power can reduce the cost of launch and operation of regenerative life support systems. Variations in power may be quite severe and may manifest as surges or spikes, While the power plant may have some ability to deal with these variations, with batteries for example, over-capacity is expensive and does nothing to address the fundamental issue of excessive demand. Because the power unit must be sized to accommodate the largest demand, avoiding power spikes has the potential to reduce the required size of the power plant while at the same time increasing the dependability of the system. Scheduling of processors can help to reduce potential power spikes. However, not all power-consuming equipment is easily scheduled. Therefore, active power management is needed to further decrease the risk of surges or spikes. We investigate the use of a hierarchical scheme to actively manage power for a model of a regenerative life support system. Local level controllers individually determine subsystem power usage. A higher level controller monitors overall system power and detects surges or spikes. When a surge condition is detected, the higher level controller conducts an 'auction' and describes subsystem power usage to re-allocate power. The result is an overall reduction in total power during a power surge. The auction involves each subsystem making a 'bid' to buy or sell power based on local needs. However, this re-allocation cannot come at the expense of life support function. To this end, participation in the auction is restricted to those processes meeting certain tolerance constraints. These tolerances represent acceptable limits within which system processes can be operated. We present a simulation model and discuss some of our results.

  4. Bimix antimicrobial scaffolds for regenerative endodontics.

    PubMed

    Palasuk, Jadesada; Kamocki, Krzysztof; Hippenmeyer, Lauren; Platt, Jeffrey A; Spolnik, Kenneth J; Gregory, Richard L; Bottino, Marco C

    2014-11-01

    Eliminating and/or inhibiting bacterial growth within the root canal system has been shown to play a key role in the regenerative outcome. The aim of this study was to synthesize and determine in vitro both the antimicrobial effectiveness and cytocompatibility of bimix antibiotic-containing polydioxanone-based polymer scaffolds. Antibiotic-containing (metronidazole [MET] and ciprofloxacin [CIP]) polymer solutions (distinct antibiotic weight ratios) were spun into fibers as a potential mimic to the double antibiotic paste (DAP, a MET/CIP mixture). Fiber morphology, chemical characteristics, and tensile strength were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy, and tensile testing, respectively. Antimicrobial efficacy was tested over time (aliquot collection) against Enterococcus faecalis (Ef), Porphyromonas gingivalis (Pg), and Fusobacterium nucleatum (Fn). Similarly, cytotoxicity was evaluated in human dental pulp stem cells. Data were statistically analyzed (P < .05). Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed that electrospinning was able to produce antibiotic-containing fibers with a diameter mostly in the nanoscale. The tensile strength of 1:1MET/CIP scaffolds was significantly (P < .05) higher than pure polydioxanone (control). Meanwhile, all other groups presented similar strength as the control. Aliquots obtained from antibiotic-containing scaffolds inhibited the growth of Ef, Pg, and Fn, except pure MET, which did not show an inhibitory action toward Pg or Fn. Antibiotic-containing aliquots promoted slight human dental pulp stem cell viability reduction, but none of them were considered to be cytotoxic. Our data suggest that the incorporation of multiple antibiotics within a nanofibrous scaffold holds great potential toward the development of a drug delivery system for regenerative endodontics. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All

  5. Power Management in Regenerative Life Support Systems

    NASA Technical Reports Server (NTRS)

    Crawford, Sekou; Pawlowski, Christopher; Finn, Cory; Mead, Susan C. (Technical Monitor)

    1999-01-01

    Effective management of power can reduce the cost of launch and operation of regenerative life support systems. Variations in power may be quite severe and may manifest as surges or spikes, While the power plant may have some ability to deal with these variations, with batteries for example, over-capacity is expensive and does nothing to address the fundamental issue of excessive demand. Because the power unit must be sized to accommodate the largest demand, avoiding power spikes has the potential to reduce the required size of the power plant while at the same time increasing the dependability of the system. Scheduling of processors can help to reduce potential power spikes. However, not all power-consuming equipment is easily scheduled. Therefore, active power management is needed to further decrease the risk of surges or spikes. We investigate the use of a hierarchical scheme to actively manage power for a model of a regenerative life support system. Local level controllers individually determine subsystem power usage. A higher level controller monitors overall system power and detects surges or spikes. When a surge condition is detected, the higher level controller conducts an 'auction' and describes subsystem power usage to re-allocate power. The result is an overall reduction in total power during a power surge. The auction involves each subsystem making a 'bid' to buy or sell power based on local needs. However, this re-allocation cannot come at the expense of life support function. To this end, participation in the auction is restricted to those processes meeting certain tolerance constraints. These tolerances represent acceptable limits within which system processes can be operated. We present a simulation model and discuss some of our results.

  6. Materials science tools for regenerative medicine

    NASA Astrophysics Data System (ADS)

    Richardson, Wade Nicholas

    Regenerative therapies originating from recent technological advances in biology could revolutionize medicine in the coming years. In particular, the advent of human pluripotent stem cells (hPSCs), with their ability to become any cell in the adult body, has opened the door to an entirely new way of treating disease. However, currently these medical breakthroughs remain only a promise. To make them a reality, new tools must be developed to surmount the new technical hurdles that have arisen from dramatic departure from convention that this field represents. The collected work presented in this dissertation covers several projects that seek to apply the skills and knowledge of materials science to this tool synthesizing effort. The work is divided into three chapters. The first deals with our work to apply Raman spectroscopy, a tool widely used for materials characterization, to degeneration in cartilage. We have shown that Raman can effectively distinguish the matrix material of healthy and diseased tissue. The second area of work covered is the development of a new confocal image analysis for studying hPSC colonies that are chemical confined to uniform growth regions. This tool has important application in understanding the heterogeneity that may slow the development of hPSC -based treatment, as well as the use of such confinement in the eventually large-scale manufacture of hPSCs for therapeutic use. Third, the use of structural templating in tissue engineering scaffolds is detailed. We have utilized templating to tailor scaffold structures for engineering of constructs mimicking two tissues: cartilage and lung. The work described here represents several important early steps towards large goals in regenerative medicine. These tools show a great deal of potential for accelerating progress in this field that seems on the cusp of helping a great many people with otherwise incurable disease.

  7. Platelet gel: applications in dental regenerative surgery.

    PubMed

    Forni, Franco; Marzagalli, Massimo; Tesei, Patrizia; Grassi, Alessandra

    2013-01-01

    Platelet growth factors obtained from platelet-rich plasma (PRP) are used in prosthetic and periodontal regenerative therapy in dentistry. Increased microvascular proliferation in the first 20 days is followed by enhanced osteoblast activity and immature osteoid formation within 3-6 weeks, improving the quality and quantity of newly formed bone tissue. The aim of this study was to evaluate, through three-dimensional X-ray monitoring, the amount of bone obtained after bone regeneration treatment with platelet gel from autologous PRP. Patients eligible for regenerative treatment of atrophic alveolar bone of the maxilla or mandible were studied. The patients' autologous whole blood was collected at the Department of Immunology and Transfusion of San Matteo Hospital for the preparation of platelet gel. The bone at the treated sites was analysed prior to and 4 months after the treatment using the three-dimensional X-ray system Galileos. Over a period of 6 years, 133 patients were treated: 304 implants were inserted and there were five cases of failure. The regenerated bone area consisted of histologically immature osteoid tissue composed of thin trabeculae of vital bone and nuclei of osteocytes, associated with fibro-connective tissue. This co-operative trial between the Transfusion Centre, for standardised production and validation of the platelet gel, and the Dental Surgery room for its application showed that the technique appears effective and safe. Although difficulties were encountered because of the small sample size and the inability to carry out long-term histological controls, the use of small amounts of PRP (5-10%) combined with autologous bone (15-20%) and alloplastic material appears to reduce the need for bone grafting.

  8. Non-aqueous electrolytes for electrochemical cells

    DOEpatents

    Zhang, Zhengcheng; Dong, Jian; Amine, Khalil

    2016-06-14

    An electrolyte electrochemical device includes an anodic material and an electrolyte, the electrolyte including an organosilicon solvent, a salt, and a hybrid additiving having a first and a second compound, the hybrid additive configured to form a solid electrolyte interphase film on the anodic material upon application of a potential to the electrochemical device.

  9. Antireduction Insulator For Solid-Electrolyte Cell

    NASA Technical Reports Server (NTRS)

    Shlichta, Paul J.

    1990-01-01

    Depletion of oxygen from electrolyte prevented. Proposed to add layer of electrical insulation between solid electrolyte and portion of porous negative electrode under negative metal contact in solid-electrolyte cell. Helps maintain efficiency of cell by preventing "shadow" effect degrading portion of electrolyte under negative contact and sometimes near seals.

  10. Composite Solid Electrolyte For Lithium Cells

    NASA Technical Reports Server (NTRS)

    Peled, Emmanuel; Nagasubramanian, Ganesan; Halpert, Gerald; Attia, Alan I.

    1994-01-01

    Composite solid electrolyte material consists of very small particles, each coated with thin layer of Lil, bonded together with polymer electrolyte or other organic binder. Material offers significant advantages over other solid electrolytes in lithium cells and batteries. Features include high ionic conductivity and strength. Composite solid electrolyte expected to exhibit flexibility of polymeric electrolytes. Polymer in composite solid electrolyte serves two purposes: used as binder alone, conduction taking place only in AI2O3 particles coated with solid Lil; or used as both binder and polymeric electrolyte, providing ionic conductivity between solid particles that it binds together.

  11. Electrolyte disorders in the elderly.

    PubMed

    Adams, K R; Martin, J A

    1991-01-01

    Electrolyte abnormalities in the elderly are common and it is most important to establish if drug treatment is the cause, as this is so easily remediable. The vast majority of electrolyte disturbances will settle with treatment of the underlying condition. Great attention must be paid to fluid balance to establish if the patient is receiving too little, which could induce hypernatraemia, or too much, particularly after surgery, which may induce hyponatraemia. Electrolyte levels should be checked ideally before and certainly after the prescription of diuretics. In the elderly it is important that the electrolyte levels be checked if the patient exhibits any vague symptoms, particularly if they are taking a diuretic. Care must be taken in replacing potassium as in most cases this is unnecessary and may have a significant morbidity.

  12. Composite solid polymer electrolyte membranes

    DOEpatents

    Formato, Richard M.; Kovar, Robert F.; Osenar, Paul; Landrau, Nelson; Rubin, Leslie S.

    2006-05-30

    The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

  13. Electrolyte salts for power sources

    DOEpatents

    Doddapaneni, Narayan; Ingersoll, David

    1995-01-01

    Electrolyte salts for power sources comprising salts of phenyl polysulfonic acids and phenyl polyphosphonic acids. The preferred salts are alkali and alkaline earth metal salts, most preferably lithium salts.

  14. Composite solid polymer electrolyte membranes

    DOEpatents

    Formato, Richard M.; Kovar, Robert F.; Osenar, Paul; Landrau, Nelson; Rubin, Leslie S.

    2001-06-19

    The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

  15. Electrolyte salts for power sources

    DOEpatents

    Doddapaneni, N.; Ingersoll, D.

    1995-11-28

    Electrolyte salts are disclosed for power sources comprising salts of phenyl polysulfonic acids and phenyl polyphosphonic acids. The preferred salts are alkali and alkaline earth metal salts, most preferably lithium salts. 2 figs.

  16. A review of the regenerative endodontic treatment procedure

    PubMed Central

    Lee, Bin-Na; Moon, Jong-Wook; Chang, Hoon-Sang; Hwang, In-Nam; Oh, Won-Mann

    2015-01-01

    Traditionally, apexification has been used to treat immature permanent teeth that have lost pulp vitality. This technique promotes the formation of an apical barrier to close the open apex so that the filling materials can be confined to the root canal. Because tissue regeneration cannot be achieved with apexification, a new technique called regenerative endodontic treatment was presented recently to treat immature permanent teeth. Regenerative endodontic treatment is a treatment procedure designed to replace damaged pulp tissue with viable tissue which restores the normal function of the pulp-dentin structure. After regenerative endodontic treatment, continued root development and hard tissue deposition on the dentinal wall can occur under ideal circumstances. However, it is difficult to predict the result of regenerative endodontic treatment. Therefore, the purpose of this study was to summarize multiple factors effects on the result of regenerative endodontic treatment in order to achieve more predictable results. In this study, we investigated the features of regenerative endodontic treatment in comparison with those of other pulp treatment procedures and analyzed the factors that have an effect on regenerative endodontic treatment. PMID:26295020

  17. A survey of dental residents' expectations for regenerative endodontics.

    PubMed

    Manguno, Christine; Murray, Peter E; Howard, Cameron; Madras, Jonathan; Mangan, Stephen; Namerow, Kenneth N

    2012-02-01

    The objective was to survey a group of dental residents regarding their expectations for using regenerative endodontic procedures as part of future dental treatments. After institutional review board approval, the opinions of 32 dentists who were having postgraduate residency training to become specialists in a dental school were surveyed. The survey had 40 questions about professional status, ethical beliefs, judgment, and clinical practice. It was found that 83.9% of dentists had no continuing education or training in stem cells or regenerative endodontic procedures. Results showed that 96.8% of dentists are willing to receive training to be able to provide regenerative endodontic procedures for their patients. Of the total group, 49.1% of dentists already use membranes, scaffolds, or bioactive materials to provide dental treatment. It was determined that 47.3% of dentists agree that the costs of regenerative procedures should be comparable with current treatments. It was also found that 55.1% of dentists were unsure whether regenerative procedures would be successful. Dentists are supportive of using regenerative endodontic procedures in their dental practice, and they are willing to undergo extra training and to buy new technology to provide new procedures. Nevertheless, dentists also need more evidence for the effectiveness and safety of regenerative treatments before they will be recommended for most patients. Copyright © 2012. Published by Elsevier Inc.

  18. A review of the regenerative endodontic treatment procedure.

    PubMed

    Lee, Bin-Na; Moon, Jong-Wook; Chang, Hoon-Sang; Hwang, In-Nam; Oh, Won-Mann; Hwang, Yun-Chan

    2015-08-01

    Traditionally, apexification has been used to treat immature permanent teeth that have lost pulp vitality. This technique promotes the formation of an apical barrier to close the open apex so that the filling materials can be confined to the root canal. Because tissue regeneration cannot be achieved with apexification, a new technique called regenerative endodontic treatment was presented recently to treat immature permanent teeth. Regenerative endodontic treatment is a treatment procedure designed to replace damaged pulp tissue with viable tissue which restores the normal function of the pulp-dentin structure. After regenerative endodontic treatment, continued root development and hard tissue deposition on the dentinal wall can occur under ideal circumstances. However, it is difficult to predict the result of regenerative endodontic treatment. Therefore, the purpose of this study was to summarize multiple factors effects on the result of regenerative endodontic treatment in order to achieve more predictable results. In this study, we investigated the features of regenerative endodontic treatment in comparison with those of other pulp treatment procedures and analyzed the factors that have an effect on regenerative endodontic treatment.

  19. Electrolytes for lithium ion batteries

    SciTech Connect

    Vaughey, John; Jansen, Andrew N.; Dees, Dennis W.

    2014-08-05

    A family of electrolytes for use in a lithium ion battery. The genus of electrolytes includes ketone-based solvents, such as, 2,4-dimethyl-3-pentanone; 3,3-dimethyl 2-butanone(pinacolone) and 2-butanone. These solvents can be used in combination with non-Lewis Acid salts, such as Li.sub.2[B.sub.12F.sub.12] and LiBOB.

  20. Solid polymer electrolyte lithium batteries

    DOEpatents

    Alamgir, M.; Abraham, K.M.

    1993-10-12

    This invention pertains to Lithium batteries using Li ion (Li[sup +]) conductive solid polymer electrolytes composed of solvates of Li salts immobilized in a solid organic polymer matrix. In particular, this invention relates to Li batteries using solid polymer electrolytes derived by immobilizing solvates formed between a Li salt and an aprotic organic solvent (or mixture of such solvents) in poly(vinyl chloride). 3 figures.

  1. Solid polymer electrolyte lithium batteries

    DOEpatents

    Alamgir, Mohamed; Abraham, Kuzhikalail M.

    1993-01-01

    This invention pertains to Lithium batteries using Li ion (Li.sup.+) conductive solid polymer electrolytes composed of solvates of Li salts immobilized in a solid organic polymer matrix. In particular, this invention relates to Li batteries using solid polymer electrolytes derived by immobilizing solvates formed between a Li salt and an aprotic organic solvent (or mixture of such solvents) in poly(vinyl chloride).

  2. Polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Gottesfeld, S.

    The recent increase in attention to polymer electrolyte fuel cells (PEFC's) is the result of significant technical advances in this technology and the initiation of some projects for the demonstration of complete PEFC-based power system in a bus or in a passenger car. A PEFC powered vehicle has the potential for zero emission, high energy conversion efficiency and extended range compared to present day battery powered EV's. This paper describes recent achievements in R&D on PEFC's. The major thrust areas have been: (1) demonstration of membrane/electrode assemblies with stable high performance in life tests lasting 4000 hours, employing ultra-low Pt loadings corresponding to only 1/2 oz of Pt for the complete power source of a passenger car; (2) effective remedies for the high sensitivity of the Pt electrocatalyst to impurities in the fuel feed stream; and (3) comprehensive evaluation of the physicochemical properties of membrane and electrodes in the PEFC, clarifying the water management issues and enabling effective codes and diagnostics for this fuel cell.

  3. [Cancer and electrolytes imbalance].

    PubMed

    Shibata, Hiroyuki

    2010-06-01

    The electrolyte imbalance in advanced cancer patients, including hyperkalemia, hypercalcemia and hyponatremia, can be induced by various factors. Hyperkalemia is occasionally induced by chemotherapy for very large malignant tumors, due to tumor lysis syndrome. Hypercalcemia and hyponatremia are often observed in patients with breast cancer, renal cancer, prostate cancer, and the like, as a paraneoplastic syndrome. Some part of hypercalcemia results from osteolysis, but the majority is induced by hormonal factors, such as parathyroid hormone-related protein. One of the paraneoplastic causes of hyponatremia is antidiuretic hormone-producing tumor. These disorders could be morbid or even motile, resulting from encephalopathy or arrhythmia in some cases. However, it should be kept in mind that they could be improved or cured by prompt treatment. Recently, after approval of the molecular targeted drugs for epidermal growth factor receptors, such as cetuximab and panitumumab, the incidence of hypomagnesia with use of these monoclonal antibodies, is relatively frequent. In addition, small molecular targeted drugs, such as m-TORinhibitors and ABL kinase inhibitors, also exert adverse reactions including hypomagnesia and hypophosphatemia. Careful monitoring of the serum concentration of magnesium and phosphate ions, to which little attention was paid previously, is a key issue in these cases.

  4. Electrolytic decontamination of conductive materials

    NASA Astrophysics Data System (ADS)

    Campbell, George M.; Nelson, Timothy O.; Parker, John L.; Getty, Richard H.; Hergert, Tom R.; Lindahl, Kirk A.; Peppers, Larry G.

    1994-10-01

    Using the electrolytic method, we have demonstrated removal of Pu and Am from contaminated conductive material. At EG and G /Rocky Flats, we electrolytically decontaminated stainless steel. Results from this work show removal of fixed contamination, including the following geometries: planar, large radius, bolt holes, glove ports, and protruding studs. More specifically, fixed contamination was reduced from levels ranging from greater than 1 000 000 counts per minute (cpm) down to levels ranging from 1500 to 250 cpm using the electrolytic method. More recently, the electrolytic work has continued at Los Alamos National Laboratory as a joint project with EG and G/Rocky Flats. Impressively, electrolytic decontamination of Pu /Am from U surfaces (10 sq cm per side) shows decreases in swipable contamination from 500 000-1 500 000 disintegrations per minute (dpm) down to 0-2 dpm. Moreover, the solid waste product of the electrolytic method is reduced in volume by more than 50 times compared with the liquid waste produced by the previous U decontamination method -- a hot concentrated acid spray leach process.

  5. Adaptive controller for regenerative and friction braking system

    DOEpatents

    Davis, R.I.

    1990-10-16

    A regenerative and friction braking system for a vehicle having one or more road wheels driven by an electric traction motor includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the road wheels of the vehicle. A system according to this invention further includes control means for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the road wheels of the vehicle without skidding or slipping will not be exceeded. 8 figs.

  6. The Quest toward limb regeneration: a regenerative engineering approach

    PubMed Central

    Laurencin, Cato T.; Nair, Lakshmi S.

    2016-01-01

    The Holy Grail to address the clinical grand challenge of human limb loss is to develop innovative strategies to regrow the amputated limb. The remarkable advances in the scientific understanding of regeneration, stem cell science, material science and engineering, physics and novel surgical approaches in the past few decades have provided a regenerative tool box to face this grand challenge and address the limitations of human wound healing. Here we discuss the convergence approach put forward by the field of Regenerative Engineering to use the regenerative tool box to design and develop novel translational strategies to limb regeneration. PMID:27047679

  7. Regenerative endodontics: barriers and strategies for clinical translation.

    PubMed

    Mao, Jeremy J; Kim, Sahng G; Zhou, Jian; Ye, Ling; Cho, Shoko; Suzuki, Takahiro; Fu, Susan Y; Yang, Rujing; Zhou, Xuedong

    2012-07-01

    Regenerative endodontics has encountered substantial challenges toward clinical translation. The adoption by the American Dental Association of evoked pulp bleeding in immature permanent teeth is an important step for regenerative endodontics. However, there is no regenerative therapy for most endodontic diseases. Simple recapitulation of cell therapy and tissue engineering strategies that are under development for other organ systems has not led to clinical translation in regeneration endodontics. Recent work using novel biomaterial scaffolds and growth factors that orchestrate the homing of host endogenous cells represents a departure from traditional cell transplantation approaches and may accelerate clinical translation.

  8. Dedifferentiation, transdifferentiation, and reprogramming: future directions in regenerative medicine.

    PubMed

    Eguizabal, Cristina; Montserrat, Nuria; Veiga, Anna; Izpisua Belmonte, Juan Carlos

    2013-01-01

    The main goal of regenerative medicine is to replace damaged tissue. To do this it is necessary to understand in detail the whole regeneration process including differentiated cells that can be converted into progenitor cells (dedifferentiation), cells that can switch into another cell type (transdifferentiation), and somatic cells that can be induced to become pluripotent cells (reprogramming). By studying the regenerative processes in both nonmammal and mammal models, natural or artificial processes could underscore the molecular and cellular mechanisms behind these phenomena and be used to create future regenerative strategies for humans.

  9. Adaptive controller for regenerative and friction braking system

    SciTech Connect

    Davis, Roy I.

    1990-01-01

    A regenerative and friction braking system for a vehicle having one or more roadwheels driven by an electric traction motor includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the roadwheels of the vehicle. A system according to this invention further includes control means for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the roadwheels of the vehicle without skidding or slipping will not be exceeded.

  10. Biomolecule delivery to engineer the cellular microenvironment for regenerative medicine.

    PubMed

    Bishop, Corey J; Kim, Jayoung; Green, Jordan J

    2014-07-01

    To realize the potential of regenerative medicine, controlling the delivery of biomolecules in the cellular microenvironment is important as these factors control cell fate. Controlled delivery for tissue engineering and regenerative medicine often requires bioengineered materials and cells capable of spatiotemporal modulation of biomolecule release and presentation. This review discusses biomolecule delivery from the outside of the cell inwards through the delivery of soluble and insoluble biomolecules as well as from the inside of the cell outwards through gene transfer. Ex vivo and in vivo therapeutic strategies are discussed, as well as combination delivery of biomolecules, scaffolds, and cells. Various applications in regenerative medicine are highlighted including bone tissue engineering and wound healing.

  11. New Regenerative Cycle for Vapor Compression Refrigeration

    SciTech Connect

    Mark J. Bergander

    2005-08-29

    The main objective of this project is to confirm on a well-instrumented prototype the theoretically derived claims of higher efficiency and coefficient of performance for geothermal heat pumps based on a new regenerative thermodynamic cycle as comparing to existing technology. In order to demonstrate the improved performance of the prototype, it will be compared to published parameters of commercially available geothermal heat pumps manufactured by US and foreign companies. Other objectives are to optimize the design parameters and to determine the economic viability of the new technology. Background (as stated in the proposal): The proposed technology closely relates to EERE mission by improving energy efficiency, bringing clean, reliable and affordable heating and cooling to the residential and commercial buildings and reducing greenhouse gases emission. It can provide the same amount of heating and cooling with considerably less use of electrical energy and consequently has a potential of reducing our nations dependence on foreign oil. The theoretical basis for the proposed thermodynamic cycle was previously developed and was originally called a dynamic equilibrium method. This theory considers the dynamic equations of state of the working fluid and proposes the methods for modification of T-S trajectories of adiabatic transformation by changing dynamic properties of gas, such as flow rate, speed and acceleration. The substance of this proposal is a thermodynamic cycle characterized by the regenerative use of the potential energy of two-phase flow expansion, which in traditional systems is lost in expansion valves. The essential new features of the process are: (1) The application of two-step throttling of the working fluid and two-step compression of its vapor phase. (2) Use of a compressor as the initial step compression and a jet device as a second step, where throttling and compression are combined. (3) Controlled ratio of a working fluid at the first and

  12. Fluid and Electrolyte Nutrition

    NASA Technical Reports Server (NTRS)

    Lane, Helen W.; Smith, Scott M.; Leach, Carolyn S.; Rice, Barbara L.

    1999-01-01

    Studies of fluid and electrolyte homeostasis have been completed since the early human space flight programs, with comprehensive research completed on the Spacelab Life Sciences missions SLS-1 and SLS-2 flights, and more recently on the Mir 18 mission. This work documented the known shifts in fluids, the decrease in total blood volume, and indications of reduced thirst. Data from these flights was used to evaluate the nutritional needs for water, sodium, and potassium. Interpretations of the data are confounded by the inadequate energy intakes routinely observed during space flight. This in turn results in reduced fluid intake, as food provides approximately 70% water intake. Subsequently, body weight, lean body mass, total body water, and total body potassium may decrease. Given these issues, there is evidence to support a minimum required water intake of 2 L per day. Data from previous Shuttle flights indicated that water intake is 2285 +/- 715 ml/day (mean +/- SD, n=26). There are no indications that sodium intake or homeostasis is compromised during space flight. The normal or low aldosterone and urinary sodium levels suggest adequate sodium intake (4047 +/- 902 mg/day, n=26). Because excessive sodium intake is associated with hypercalciuria, the recommended maximum amount of sodium intake during flight is 3500 mg/day (i.e., similar to the Recommended Dietary Allowance, RDA). Potassium metabolism appears to be more complex. Data indicate loss of body potassium related to muscle atrophy and low dietary intake (2407 +/- 548 mg/day, n=26). Although possibly related to measurement error, the elevations in blood potassium suggest alterations in potassium homeostasis. The space RDA for minimum potassium intake is 3500 mg/day. With the documented inadequate intakes, efforts are being made to increase dietary consumption of potassium.

  13. Mean-field theory for inhomogeneous electrolytes.

    PubMed

    Yeh, Shin-Shing; Chen, Peilong

    2005-09-01

    We calculate the free energy density for inhomogeneous electrolytes based on the mean-field Debye-Hückel theory. Derived are the contributions of (1) the differential term for the electrolyte density being slow varying in one direction and (2) the boundary term for an electrolyte confined to one side of a planar interface. These contributions are shown to cause an electrolyte depletion near the air-water interfaces, which makes the surface tension increase, to be significantly larger than those predicted by previous theories. Nonuniform electrolyte densities are also computed near the water-electrolyte and electrolyte-electrolyte interfaces. Finally we calculate the interaction of two uncharged macrospheres due to the electrolyte depletion.

  14. 3. INSIDE BATCH FURNACE BUILDING, VIEW LOOKING NORTH AT REGENERATIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. INSIDE BATCH FURNACE BUILDING, VIEW LOOKING NORTH AT REGENERATIVE BATCH FURNACES ON LEFT AND 5 TON CAPACITY CHARGING MACHINE ON RIGHT. - U.S. Steel Duquesne Works, 22-Inch Bar Mill, Along Monongahela River, Duquesne, Allegheny County, PA

  15. Advancing pig cloning technologies towards application in regenerative medicine.

    PubMed

    Nagashima, H; Matsunari, H; Nakano, K; Watanabe, M; Umeyama, K; Nagaya, M

    2012-08-01

    Regenerative medicine is expected to make a significant contribution by development of novel therapeutic treatments for intractable diseases and for improving the quality of life of patients. Many advances in regenerative medicine, including basic and translational research, have been developed and tested in experimental animals; pigs have played an important role in various aspects of this work. The value of pigs as a model species is being enhanced by the generation of specially designed animals through cloning and genetic modifications, enabling more sophisticated research to be performed and thus accelerating the clinical application of regenerative medicine. This article reviews the significant aspects of the creation and application of cloned and genetically modified pigs in regenerative medicine research and considers the possible future directions of the technology. We also discuss the importance of reproductive biology as an interface between basic science and clinical medicine. © 2012 Blackwell Verlag GmbH.

  16. History of regenerative medicine: looking backwards to move forwards.

    PubMed

    Kemp, Paul

    2006-09-01

    If the song by the international popstar Sting is to be relied upon, 'History will teach us nothing'. At the risk of contradicting a one-time schoolteacher, I believe the reverse is true for regenerative medicine. In fact, I think we dismiss the past at our peril. In this review, I aim to trace the history of regenerative medicine to date. I will examine parallels with other areas of medicine and show how commercial, technical and socio/economic factors have influenced the pace and direction of the sector's evolution. I will discuss how, by learning from the past, those involved in regenerative medicine are reinventing their sector for the better. In conclusion, I will evaluate the current state of the industry, suggest what the future may hold and explain why I believe regenerative medicine is about to 'come of age'.

  17. Science and Ethics: Bridge to the Future for Regenerative Medicine

    PubMed Central

    Patricio, Ventura-Juncá

    2011-01-01

    The objective of this article is to reflect on the relationship between regenerative medicine and ethics, using as references the Aristotelian concept of what is ethical and that of Raessler Van Potter about bioethics. To do this, I will briefly describe the advances in regenerative medicine with stem cells, the strategies for producing pluripotential cells without destroying human embryos, and the great potential of stem cells to improve life for Humanity, noting that for this to be possible, it is necessary to locate the role of regenerative medicine in the context of human values and well being. In this way, this article has a real perspective of the role that regenerative medicine can play in benefitting human beings and engendering respect for human and natural environments. PMID:24298338

  18. [Regenerative medicine in head and neck reconstructive surgery].

    PubMed

    Riedel, F; Goessler, U R; Stern-Straeter, J; Riedel, K; Hörmann, K

    2008-03-01

    Autologous transplantation is regarded as the gold standard in the treatment of congenital or acquired deformities. However, the availability of autologous tissue for transplantation is often limited. Regenerative medicine aims to activate individuals' own intrinsic regenerative mechanisms and embraces tissue engineering, cell/system biology, gene therapy and stem-cell biology. Most approaches in tissue engineering are based on the expansion of small autologous cell aggregates. Tissue engineering supplemented by isolated and amplified stem cells is another very promising option for producing autologous transplants and getting over the limited availability. The association of stem cell-based tissue engineering and gene therapy allows the creation of regenerative tissue in the optimal ambience of regulatory proteins. This leads to great opportunities in the transplantation of skin, bones or cartilage. This paper presents the current status and the possible benefits, but also the limitations, of regenerative medicine in reconstructive surgery of the head and neck.

  19. Platelet-rich fibrin: a boon in regenerative endodontics.

    PubMed

    Rebentish, Priyanka D; Umashetty, Girish; Kaur, Harpreet; Doizode, Trupthi; Kaslekar, Mithun; Chowdhury, Shouvik

    2016-12-01

    Research into regenerative dentistry has contributed momentum to the field of molecular biology. Periapical surgery aims at removing periapical pathology to achieve complete wound healing and regeneration of bone and periodontal tissue. Regenerative endodontic procedures are widely being added to the current armamentarium of pulp therapy procedures. The regenerative potential of platelets has been deliberated. Platelet-rich fibrin (PRF) is a wonderful tissue-engineering product and has recently gained much popularity due its promising results in wound healing bone induction. The features of this product are an attribute of platelets which, after cellular interactions, release growth factors and have shown application in diverse disciplines of dentistry. This paper is intended to shed light onto the various prospects of PRF and to provide clinical insight into regenerative endodontic therapy.

  20. Cell sheet engineering for regenerative medicine: current challenges and strategies.

    PubMed

    Owaki, Toshiyuki; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

    2014-07-01

    Substantial progress made in the areas of stem cell research and regenerative medicine has provided a number of innovative methods to repair or regenerate defective tissues and organs. Although previous studies regarding regenerative medicine, especially those involving induced pluripotent stem cells, have been actively promoted in the past decade, there remain some challenges that need to be addressed in order to enable clinical applications. Designed for use in clinical applications, cell sheet engineering has been developed as a unique, scaffold-free method of cell processing utilizing temperature-responsive cell culture vessels. Clinical studies using cell sheets have shown positive outcomes and will be translated into clinical practice in the near future. However, several challenges stand in the way of the industrialization of cell sheet products and the widespread acceptance of regenerative medicine based on cell sheet engineering. This review describes current strategies geared towards the realization of the regenerative medicine approach.

  1. Iron serves as diffusion barrier in thermally regenerative galvanic cell

    NASA Technical Reports Server (NTRS)

    Crouthamel, C. E.

    1967-01-01

    Pure iron or iron-coated diaphragm provides a hydrogen diffusion electrode for a thermally regenerative galvanic cell. It allows the gas to diffuse through its interatomic spaces and resists the corrosive action of the cell environment.

  2. From regenerative dentistry to regenerative medicine: progress, challenges, and potential applications of oral stem cells.

    PubMed

    Xiao, Li; Nasu, Masanori

    2014-01-01

    Adult mesenchymal stem cells (MSCs) and epithelial stem cells play essential roles in tissue repair and self-healing. Oral MSCs and epithelial stem cells can be isolated from adult human oral tissues, for example, teeth, periodontal ligament, and gingiva. Cocultivated adult oral epithelial stem cells and MSCs could represent some developmental events, such as epithelial invagination and tubular structure formation, signifying their potentials for tissue regeneration. Oral epithelial stem cells have been used in regenerative medicine over 1 decade. They are able to form a stratified cell sheet under three-dimensional culture conditions. Both experimental and clinical data indicate that the cell sheets can not only safely and effectively reconstruct the damaged cornea in humans, but also repair esophageal ulcer in animal models. Oral MSCs include dental pulp stem cells (DPSCs), stem cells from exfoliated deciduous teeth (SHED), stem cells from apical papilla (SCAP), periodontal ligament stem cells (PDLSCs), and mesenchymal stem cells from gingiva (GMSCs). They are widely applied in both regenerative dentistry and medicine. DPSCs, SHED, and SCAP are able to form dentin-pulp complex when being transplanted into immunodeficient animals. They have been experimentally used for the regeneration of dental pulp, neuron, bone muscle and blood vessels in animal models and have shown promising results. PDLSCs and GMSCs are demonstrated to be ideal cell sources for repairing the damaged tissues of periodontal, muscle, and tendon. Despite the abovementioned applications of oral stem cells, only a few human clinical trials are now underway to use them for the treatment of certain diseases. Since clinical use is the end goal, their true regenerative power and safety need to be further examined.

  3. How predictable are periodontal regenerative procedures?

    PubMed

    Zohar, Ron; Tenenbaum, Howard C

    2005-10-01

    Periodontal regeneration has become one of the primary objectives of periodontal therapy. The resulting scientific endeavours have elucidated modes of periodontal wound healing, the growth of periodontal cells and their association with the surrounding matrix, and growth-promoting factors. The periodontal regeneration industry is producing better and more expensive devices, but the criteria for evaluating their success have not progressed to the same extent. Although clinical measurements of attachment level and probing depths, along with radiography, are good methods of evaluating tooth survival and prognosis, they do not indicate true biological regeneration. In addition, the regeneration industry may encourage the overuse of allografts and alloplasts which may serve as an impediment to simple wound healing. This review is a critical assessment of the clinical use of various regenerative tools, specifically bone replacements and membranes. The future of the regeneration industry may depend on the merging of various technologies and biological concepts, including the possible use of biological barriers, various bone and periodontal growth inducers, and artificial matrices that will attract or carry the cells necessary for regeneration.

  4. Regenerative life support system research and concepts

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Life support systems that involve recycling of atmospheres, water, food and waste are so complex that models incorporating all the interactions and relationships are vital to design, development, simulations, and ultimately to control of space qualified systems. During early modeling studies, FORTRAN and BASIC programs were used to obtain numerical comparisons of the performance of different regenerative concepts. Recently, models were made by combining existing capabilities with expert systems to establish an Intelligent Design Support Environment for simpliflying user interfaces and to address the need for the engineering aspects. Progress was also made toward modeling and evaluating the operational aspects of closed loop life support systems using Time-step and Dynamic simulations over a period of time. Example models are presented which show the status and potential of developed modeling techniques. For instance, closed loop systems involving algae systeMs for atmospheric purification and food supply augmentation, plus models employing high plants and solid waste electrolysis are described and results of initial evaluations are presented.

  5. Translating Regenerative Biomaterials Into Clinical Practice.

    PubMed

    Stace, Edward T; Dakin, Stephanie G; Mouthuy, Pierre-Alexis; Carr, Andrew J

    2016-01-01

    Globally health care spending is increasing unsustainably. This is especially true of the treatment of musculoskeletal (MSK) disease where in the United States the MSK disease burden has doubled over the last 15 years. With an aging and increasingly obese population, the surge in MSK related spending is only set to worsen. Despite increased funding, research and attention to this pressing health need, little progress has been made toward novel therapies. Tissue engineering and regenerative medicine (TERM) strategies could provide the solutions required to mitigate this mounting burden. Biomaterial-based treatments in particular present a promising field of potentially cost-effective therapies. However, the translation of a scientific development to a successful treatment is fraught with difficulties. These barriers have so far limited translation of TERM science into clinical treatments. It is crucial for primary researchers to be aware of the barriers currently restricting the progression of science to treatments. Researchers need to act prospectively to ensure the clinical, financial, and regulatory hurdles which seem so far removed from laboratory science do not stall or prevent the subsequent translation of their idea into a treatment. The aim of this review is to explore the development and translation of new treatments. Increasing the understanding of these complexities and barriers among primary researchers could enhance the efficiency of biomaterial translation. © 2015 Wiley Periodicals, Inc.

  6. Advent and maturation of regenerative medicine.

    PubMed

    Mhashilkar, Abner M; Atala, Anthony

    2012-11-01

    The field of regenerative medicine (RM), encompassing stem cell (SC) technologies, therapeutics, tissue engineering (TE), biomaterials, scaffolds and other enabling technologies provides a wide gamut of tools and tracks to combat, manage and hopefully cure serious human and animal injuries, dysfunctions and diseases. This review illustrates the trends that are becoming the major platforms in this field. The last 10 years in itself has seen major definitive observations, including multi-track directives of adult stem cell translational technologies, tissue and organ engineering protocols, iPS cell applications and understanding of the role of cancer stem cells to develop effective anti-cancer regimens. With the rapid advances of RM translational research, further advances are expected to be implemented for personalized repair and curative outcomes. RM future is bright although laden with challenges of global fragmentation which needs coherent consolidation, stringent cost and time effective regulation and long-term funding mechanisms, so clinical and diagnostic solutions are realized and recognized to combat unmet medical needs.

  7. Regenerative Capacity of Macrophages for Remyelination

    PubMed Central

    Rawji, Khalil S.; Mishra, Manoj K.; Yong, V. Wee

    2016-01-01

    White matter injury, consisting of loss of axons, myelin, and oligodendrocytes, is common in many neurological disorders and is believed to underlie several motor and sensory deficits. Remyelination is the process in which the insulative myelin sheath is restored to axons, thereby facilitating recovery from functional loss. Remyelination proceeds with oligodendrocyte precursor cells (OPCs) that differentiate into oligodendrocytes to synthesize the new myelin sheath after demyelination. This process is influenced by several factors, including trophic factors, inhibitory molecules in the lesion microenvironment, age of the subject, as well as the inflammatory response. Currently studied strategies that enhance remyelination consist of pharmacological approaches that directly induce OPC differentiation or using agents to neutralize the inhibitory microenvironment. Another strategy is to harness a reparative inflammatory response. This response, coordinated by central nervous system resident microglia and peripherally-derived infiltrating macrophages, has been shown to be important in the remyelination process. These innate immune cells perform important functions in remyelination, including the proteolysis and phagocytosis of inhibitory molecules present in the lesion microenvironment, the provision of trophic and metabolic factors to OPCs, in addition to iron handling capacity. Additionally, an initial pro-inflammatory phase followed by a regulatory/anti-inflammatory phase has been shown to be important for OPC proliferation and differentiation, respectively. This review will discuss the beneficial roles of macrophages/microglia in remyelination and discuss therapeutic strategies to obtain the optimal regenerative macrophage phenotype for enhanced remyelination. PMID:27243011

  8. New biomimetic directions in regenerative ophthalmology.

    PubMed

    Green, David W; Watson, Gregory S; Watson, Jolanta; Abraham, Samuel J K

    2012-03-01

    One of the most complete and permanent ways of treating many causes of visual impairment and blindness is to replace the entire affected tissue with pre-cultured ocular tissues supported and maintained on biomaterial frameworks. One direction towards enhancing ocular tissue regeneration on biomaterials, in the laboratory is by applying biomimicry. Specifically to engineer biomaterials with important functional elements of the native extracellular matrices, such as topography, that support and organise cells into coherent tissues. Further problems in regenerative ophthalmology can be potentially solved through application of biomimicry. They include, more efficient ways of moving and transplanting cultivated tissues into correct therapeutic locations inside the eye and scar-less, non-destructive healing of surgical incisions and wounds, to repair structural integrity of tissues at the ocular surface. Two examples are given to show this potential for redeveloping an ocular epithelium onto a nanostructured insect wing surface and producing an origami membrane modelled on deployable structures in nature. Efforts to harness natural innovation will eventually provide unique designs and structures that cannot for now be made synthetically, for regeneration of clinically acceptable ocular tissues.

  9. Recent advances in acellular regenerative tissue scaffolds.

    PubMed

    Protzman, Nicole M; Brigido, Stephen A

    2015-01-01

    The management of chronic wounds is a considerable challenge for foot and ankle surgeons. The well-established tenets of adequate vascular supply, debridement with eradication of infection, and offloading must be employed in the management of all extremity wounds. Regenerative scaffolds are a viable means of reestablishing a favorable wound environment. The matrix facilitates cell migration, chemoattraction, angiogenesis, wound bed granulation, and expedited wound closure. Although studies have demonstrated success with acellular matrices, a multimodal approach should always be employed to improve healing success. Negative pressure wound therapy, compression, offloading, and antibiotics are advocated to improve outcomes. Acellular graft selection requires a multifactorial analysis, taking into consideration the specific patient and wound characteristics as well as the differences between acellular matrices. Patient age, comorbidities, activity level, and ability to comply with protocol as well as wound etiology, duration, depth, surface area, exudate, bacterial burden, location, vascular status, ischemic status, and presentation are all critical components. To effectively choose a matrix, the clinician must have a comprehensive understanding of the products available and the data validating their use. The mechanisms by which the acellular matrix accelerates wound healing and increases the likelihood of wound healing continue to be investigated. However, it is clear that these acellular biologic tissue scaffolds are incorporating into the host tissue, with resultant revascularization and cellular repopulation. Moving forward, additional investigations examining the effectiveness of acellular biologic tissue scaffolds to improve healing in complex, nondiabetic wounds are warranted.

  10. Liver-Regenerative Transplantation: Regrow and Reset

    PubMed Central

    de l’Hortet, A. Collin; Takeishi, K.; Guzman-Lepe, J.; Handa, K.; Matsubara, K.; Fukumitsu, K.; Dorko, K.; Presnell, S. C.; Yagi, H.; Soto-Gutierrez, A.

    2016-01-01

    Liver transplantation, either a partial liver from a living or deceased donor or a whole liver from a deceased donor, is the only curative therapy for severe end-stage liver disease. Only one-third of those on the liver transplant waiting list will be transplanted, and the demand for livers is projected to increase 23% in the next 20 years. Consequently, organ availability is an absolute constraint on the number of liver transplants that can be performed. Regenerative therapies aim to enhance liver tissue repair and regeneration by any means available (cell repopulation, tissue engineering, biomaterials, proteins, small molecules, and genes). Recent experimental work suggests that liver repopulation and engineered liver tissue are best suited to the task if an unlimited availability of functional induced pluripotent stem (iPS)–derived liver cells can be achieved. The derivation of iPS cells by reprogramming cell fate has opened up new lines of investigation, for instance, the generation of iPS-derived xenogeneic organs or the possibility of simply inducing the liver to reprogram its own hepatocyte function after injury. We reviewed current knowledge about liver repopulation, generation of engineered livers and reprogramming of liver function. We also discussed the numerous barriers that have to be overcome for clinical implementation. PMID:26699680

  11. Introduction to stem cells and regenerative medicine.

    PubMed

    Kolios, George; Moodley, Yuben

    2013-01-01

    Stem cells are a population of undifferentiated cells characterized by the ability to extensively proliferate (self-renewal), usually arise from a single cell (clonal), and differentiate into different types of cells and tissue (potent). There are several sources of stem cells with varying potencies. Pluripotent cells are embryonic stem cells derived from the inner cell mass of the embryo and induced pluripotent cells are formed following reprogramming of somatic cells. Pluripotent cells can differentiate into tissue from all 3 germ layers (endoderm, mesoderm, and ectoderm). Multipotent stem cells may differentiate into tissue derived from a single germ layer such as mesenchymal stem cells which form adipose tissue, bone, and cartilage. Tissue-resident stem cells are oligopotent since they can form terminally differentiated cells of a specific tissue. Stem cells can be used in cellular therapy to replace damaged cells or to regenerate organs. In addition, stem cells have expanded our understanding of development as well as the pathogenesis of disease. Disease-specific cell lines can also be propagated and used in drug development. Despite the significant advances in stem cell biology, issues such as ethical controversies with embryonic stem cells, tumor formation, and rejection limit their utility. However, many of these limitations are being bypassed and this could lead to major advances in the management of disease. This review is an introduction to the world of stem cells and discusses their definition, origin, and classification, as well as applications of these cells in regenerative medicine.

  12. High power, high beam quality regenerative amplifier

    DOEpatents

    Hackel, L.A.; Dane, C.B.

    1993-08-24

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  13. High power, high beam quality regenerative amplifier

    DOEpatents

    Hackel, Lloyd A.; Dane, Clifford B.

    1993-01-01

    A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through the gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.

  14. Bioactive nanofibrous scaffolds for regenerative endodontics.

    PubMed

    Bottino, M C; Kamocki, K; Yassen, G H; Platt, J A; Vail, M M; Ehrlich, Y; Spolnik, K J; Gregory, R L

    2013-11-01

    Here we report the synthesis, materials characterization, antimicrobial capacity, and cytocompatibility of novel antibiotic-containing scaffolds. Metronidazole (MET) or Ciprofloxacin/(CIP) was mixed with a polydioxanone (PDS)polymer solution at 5 and 25 wt% and processed into fibers. PDS fibers served as a control. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), tensile testing, and high-performance liquid chromatography (HPLC) were used to assess fiber morphology, chemical structure, mechanical properties, and drug release, respectively. Antimicrobial properties were evaluated against those of Porphyromonas gingivalis/Pg and Enterococcus faecalis/Ef. Cytotoxicity was assessed in human dental pulp stem cells (hDPSCs). Statistics were performed, and significance was set at the 5% level. SEM imaging revealed a submicron fiber diameter. FTIR confirmed antibiotic incorporation. The tensile values of hydrated 25 wt% CIP scaffold were significantly lower than those of all other groups. Analysis of HPLC data confirmed gradual, sustained drug release from the scaffolds over 48 hrs. CIP-containing scaffolds significantly (p < .00001) inhibited biofilm growth of both bacteria. Conversely, MET-containing scaffolds inhibited only Pg growth. Agar diffusion confirmed the antimicrobial properties against specific bacteria for the antibiotic-containing scaffolds. Only the 25 wt% CIP-containing scaffolds were cytotoxic. Collectively, this study suggests that polymer-based antibiotic-containing electrospun scaffolds could function as a biologically safe antimicrobial drug delivery system for regenerative endodontics.

  15. PLURIPOTENT STEM CELL APPLICATIONS FOR REGENERATIVE MEDICINE

    PubMed Central

    Angelos, Mathew G.; Kaufman, Dan S.

    2015-01-01

    Purpose of Review In this review, we summarize the current status of clinical trials using therapeutic cells produced from human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). We also discuss combined cell and gene therapy via correction of defined mutations in human pluripotent stem cells and provide commentary on key obstacles facing wide-scale clinical adoption of pluripotent stem cell-based therapy. Recent Findings Initial data suggest hESC/hiPSC-derived cell products used for retinal repair and spinal cord injury are safe for human use. Early stage studies for treatment of cardiac injury and diabetes are also in progress. However, there remain key concerns regarding the safety and efficacy of these cells that need to be addressed in additional well-designed clinical trials. Advances using the CRISPR/Cas9 gene-editing system offer an improved tool for more rapid and on-target gene correction of genetic diseases. Combined gene and cell therapy using human pluripotent stem cells may provide an additional curative approach for disabling or lethal genetic and degenerative diseases where there are currently limited therapeutic opportunities. Summary Human pluripotent stem cells are emerging as a promising tool to produce cells and tissues suitable for regenerative therapy for a variety of genetic and degenerative diseases. PMID:26536430

  16. Unitized Regenerative Fuel Cell System Development

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth A.

    2003-01-01

    Unitized Regenerative Fuel Cells (URFC) have recently been developed by several fuel cell manufacturers. These manufacturers have concentrated their efforts on the development of the cell stack technology itself, and have not up to this point devoted much effort to the design and development of the balance of plant. A fuel cell technology program at the Glenn Research Center (GRC) that has as its goal the definition and feasibility testing of the URFC system balance of plant. Besides testing the feasibility, the program also intends to minimize the system weight, volume, and parasitic power as its goal. The design concept currently being developed uses no pumps to circulate coolant or reactants, and minimizes the ancillary components to only the oxygen and hydrogen gas storage tanks, a water storage tank, a loop heat pipe to control the temperature and two pressure control devices to control the cell stack pressures during operation. The information contained in this paper describes the design and operational concepts employed in this concept. The paper also describes the NASA Glenn research program to develop this concept and test its feasibility.

  17. Airway transplantation: a challenge for regenerative medicine.

    PubMed

    Martinod, Emmanuel; Seguin, Agathe; Radu, Dana M; Boddaert, Guillaume; Chouahnia, Kader; Fialaire-Legendre, Anne; Dutau, Hervé; Vénissac, Nicolas; Marquette, Charles-Hugo; Baillard, Christophe; Valeyre, Dominique; Carpentier, Alain

    2013-07-29

    After more than 50 years of research, airway transplantation remains a major challenge in the fields of thoracic surgery and regenerative medicine. Five principal types of tracheobronchial substitutes, including synthetic prostheses, bioprostheses, allografts, autografts and bioengineered conduits have been evaluated experimentally in numerous studies. However, none of these works have provided a standardized technique for the replacement of the airways. More recently, few clinical attempts have offered encouraging results with ex vivo or stem cell-based engineered airways and tracheal allografts implanted after heterotopic revascularization. In 1997, we proposed a novel approach: the use of aortic grafts as a biological matrix for extensive airway reconstruction. In vivo regeneration of epithelium and cartilage were demonstrated in animal models. This led to the first human applications using cryopreserved aortic allografts that present key advantages because they are available in tissue banks and do not require immunosuppressive therapy. Favorable results obtained in pioneering cases have to be confirmed in larger series of patients with extensive tracheobronchial diseases.

  18. REGENERATIVE MEDICINE AS APPLIED TO GENERAL SURGERY

    PubMed Central

    Orlando, Giuseppe; Wood, Kathryn J; De Coppi, Paolo; Baptista, Pedro M; Binder, Kyle W; Bitar, Khalil N; Breuer, Christopher; Burnett, Luke; Christ, George; Farney, Alan; Figliuzzi, Marina; Holmes, James H; Koch, Kenneth; Macchiarini, Paolo; Sani, Sayed-Hadi Mirmalek; Opara, Emmanuel; Remuzzi, Andrea; Rogers, Jeffrey; Saul, Justin M; Seliktar, Dror; Shapira-Schweitzer, Keren; Smith, Tom; Solomon, Daniel; Van Dyke, Mark; Yoo, James J; Zhang, Yuanyuan; Atala, Anthony; Stratta, Robert J; Soker, Shay

    2012-01-01

    The present review illustrates the state of the art of regenerative medicine (RM) as applied to surgical diseases and demonstrates that this field has the potential to address some of the unmet needs in surgery. RM is a multidisciplinary field whose purpose is to regenerate in vivo or ex vivo human cells, tissues or organs in order to restore or establish normal function through exploitation of the potential to regenerate, which is intrinsic to human cells, tissues and organs. RM uses cells and/or specially designed biomaterials to reach its goals and RM-based therapies are already in use in several clinical trials in most fields of surgery. The main challenges for investigators are threefold: Creation of an appropriate microenvironment ex vivo that is able to sustain cell physiology and function in order to generate the desired cells or body parts; identification and appropriate manipulation of cells that have the potential to generate parenchymal, stromal and vascular components on demand, both in vivo and ex vivo; and production of smart materials that are able to drive cell fate. PMID:22330032

  19. Cold end fouling regenerative air preheaters

    SciTech Connect

    Levy, E.; D`Agostini, M.; Sarunac, N.; Yilmaz, A.

    1996-05-01

    Condensation of sulfuric acid occurs in the cold end flow passages of a regenerative air preheater (APH) when local metal temperatures fall beneath the acid dew point of the flue gas. In coal-fired units, the acid condensate acts as an adhesive for fly ash particulate, the deposition of which gradually reduces the cross-sectional area of the passage, leading to higher gas pressure drops and increased fan power requirements. In units which are fan-limited, costly unit derates and forced outages for APH cleaning often occur. Although optimization of APH operation is a highly unit specific issue, the method of approaching the problem is fairly general and can involve combinations of theoretical analysis, field measurements and proper data regression. This paper describes case studies of the APH acid condensation and fouling characteristics at three different coal-fired utility boilers, which illustrate specific applications of the general optimization technique. The approach is also valid for units which employ ammonia injection.

  20. Recent advancements in regenerative dentistry: A review.

    PubMed

    Amrollahi, Pouya; Shah, Brinda; Seifi, Amir; Tayebi, Lobat

    2016-12-01

    Although human mouth benefits from remarkable mechanical properties, it is very susceptible to traumatic damages, exposure to microbial attacks, and congenital maladies. Since the human dentition plays a crucial role in mastication, phonation and esthetics, finding promising and more efficient strategies to reestablish its functionality in the event of disruption has been important. Dating back to antiquity, conventional dentistry has been offering evacuation, restoration, and replacement of the diseased dental tissue. However, due to the limited ability and short lifespan of traditional restorative solutions, scientists have taken advantage of current advancements in medicine to create better solutions for the oral health field and have coined it "regenerative dentistry." This new field takes advantage of the recent innovations in stem cell research, cellular and molecular biology, tissue engineering, and materials science etc. In this review, the recently known resources and approaches used for regeneration of dental and oral tissues were evaluated using the databases of Scopus and Web of Science. Scientists have used a wide range of biomaterials and scaffolds (artificial and natural), genes (with viral and non-viral vectors), stem cells (isolated from deciduous teeth, dental pulp, periodontal ligament, adipose tissue, salivary glands, and dental follicle) and growth factors (used for stimulating cell differentiation) in order to apply tissue engineering approaches to dentistry. Although they have been successful in preclinical and clinical partial regeneration of dental tissues, whole-tooth engineering still seems to be far-fetched, unless certain shortcomings are addressed. Copyright © 2016 Elsevier B.V. All rights reserved.