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1

Anode for a Secondary, High-Temperature Electrochemical Cell.  

National Technical Information Service (NTIS)

A high-temperature, secondary electrochemical cell includes an anode containing lithium, an electrolyte containing lithium ions, and a cathode containing a chalcogen material such as sulfur or a metallic sulfide. The anode includes a porous substrate form...

D. R. Vissers B. S. Tani

1976-01-01

2

Electrochemical Cell.  

National Technical Information Service (NTIS)

An improved secondary electrochemical cell is disclosed having a negative electrode of lithium aluminum, a positive electrode of iron sulfide, a molten electrolyte of lithium chloride and potassium chloride, and the combination that the fully charged theo...

T. D. Kaun

1984-01-01

3

Calcium alloy as active material in secondary electrochemical cell  

DOEpatents

Calcium alloys such as calcium-aluminum and calcium-silicon, are employed as active material within a rechargeable negative electrode of an electrochemical cell. Such cells can use a molten salt electrolyte including calcium ions and a positive electrode having sulfur, sulfides, or oxides as active material. The calcium alloy is selected to prevent formation of molten calcium alloys resulting from reaction with the selected molten electrolytic salt at the cell operating temperatures.

Roche, Michael F. (Lombard, IL); Preto, Sandra K. (Stickney, IL); Martin, Allan E. (Woodridge, IL)

1976-01-01

4

Primary and Secondary Room Temperature Molten Salt Electrochemical Cells.  

National Technical Information Service (NTIS)

Three primary cells (a, b, and c) and two secondary cell candidates (d and e) were examined using room temperature molten salts as electrolytes in each case: (a) A1 anode / A1C13-MEIC1 (N=0.37) // FeC13-MEIC1 (N=0.33) / W cathode (b) A1 anode / A1C13-MEIC...

G. F. Reynolds C. J. Dymek

1985-01-01

5

Corrosion resistant positive electrode for high-temperature, secondary electrochemical cell  

Microsoft Academic Search

The corrosion rate of low carbon steel within a positive electrode of a high-temperature, secondary electrochemical cell that includes FeS as active material is substantially reduced by incorporating therein finely divided iron powder in stoichiometric excess to the amount required to form FeS in the fully charged electrode. The cell typically includes an alkali metal or alkaline earth metal as

N. C. Otto; J. E. Battles; J. A. Smaga; B. J. Warner

1983-01-01

6

Corrosion resistant positive electrode for high-temperature, secondary electrochemical cell  

Microsoft Academic Search

The corrosion rate of low carbon steel within a positive electrode of a high-temperature, secondary electrochemical cell that includes FeS as active material is substantially reduced by incorporating therein finely divided iron powder in stoichiometric excess to the amount required to form FeS in the fully charged electrode. The cell typically includes an alkali metal or alkaline earth metal as

N. C. Otto; B. T. Warner; J. A. Smaga; J. E. Battles

1982-01-01

7

Corrosion resistant positive electrode for high-temperature, secondary electrochemical cell  

DOEpatents

The corrosion rate of low carbon steel within a positive electrode of a high-temperature, secondary electrochemical cell that includes FeS as active material is substantially reduced by incorporating therein finely divided iron powder in stoichiometric excess to the amount required to form FeS in the fully charged electrode. The cell typically includes an alkali metal or alkaline earth metal as negative electrode active material and a molten metal halide salt as electrolyte. The excess iron permits use of inexpensive carbon steel alloys that are substantially free of the costly corrosion resistant elements chromium, nickel and molybdenum while avoiding shorten cell life resulting from high corrosion rates.

Otto, Neil C. (Chicago, IL); Warner, Barry T. (South Holland, IL); Smaga, John A. (Lemont, IL); Battles, James E. (Oak Forest, IL)

1983-01-01

8

Electrochemical cell  

SciTech Connect

An improved secondary electrochemical cell is disclosed having a negative electrode of lithium aluminum, a positive electrode of iron sulfide, a molten electrolyte of lithium chloride and potassium chloride, and the combination that the fully charged theoretical capacity of the negative electrode is in the range of 0.5-1.0 that of the positive electrode. The cell thus is negative electrode limiting during discharge cycling. Preferably, the negative electrode contains therein, in the approximate range of 1-10 volume % of the electrode, an additive from the materials of graphitized carbon, aluminum-iron alloy, and/or magnesium oxide.

Kaun, T.D.

1984-05-01

9

Method of forming components for a high-temperature secondary electrochemical cell  

DOEpatents

A method of forming a component for a high-temperature secondary electrochemical cell having a positive electrode including a sulfide selected from the group consisting of iron sulfides, nickel sulfides, copper sulfides and cobalt sulfides, a negative electrode including an alloy of aluminum and an electrically insulating porous separator between said electrodes. The improvement comprises forming a slurry of solid particles dispersed in a liquid electrolyte such as the lithium chloride-potassium chloride eutetic, casting the slurry into a form having the shape of one of the components and smoothing the exposed surface of the slurry, cooling the cast slurry to form the solid component, and removing same. Electrodes and separators can be thus formed.

Mrazek, Franklin C. (Hickory Hills, IL); Battles, James E. (Oak Forest, IL)

1983-01-01

10

Electrode for electrochemical cell  

DOEpatents

An electrode structure for a secondary electrochemical cell includes an outer enclosure defining a compartment containing electrochemical active material. The enclosure includes a rigid electrically conductive metal sheet with perforated openings over major side surfaces. The enclosure can be assembled as first and second trays each with a rigid sheet of perforated electrically conductive metal at major side surfaces and normally extending flanges at parametric margins. The trays can be pressed together with moldable active material between the two to form an expandable electrode. A plurality of positive and negative electrodes thus formed are arranged in an alternating array with porous frangible interelectrode separators within the housing of the secondary electrochemical cell.

Kaun, T.D.; Nelson, P.A.; Miller, W.E.

1980-05-09

11

Electrochemical cell  

SciTech Connect

An electrochemical cell is described comprising a negative electrode. The electrochemically active material consists of an intermetallic compound forming a hydride with hydrogen, which compound has the CaCu/sub 5/-structure and the compositional formula AB/sub m/C/sub n/, where m+n is between 4.8 and 5.4, and where n is between 0.05 and 0.6. A consists of Mischmetall or of at least one element selected from the group consisting of Y, Ti, Hf, Zr, Ca, Th, La and the remaining rare earth metals, in which the total atomic quantities of the elements Y, Ti, Hf and Zr may not be more than 40% of A. B consists of two or more elements selected from the group consisting of Ni, Co, Cu, Fe and Mn, the maximum atomic quantity per gram atom of A is being for Ni:3.5, for Co:3.5, for Cu:3.5, for Fe:2.0 and for Mn:1.0. C consists of at least one element selected from the group consisting of Al, Cr and Si in the following atomic quantities: Al:0.05-0.6, Cr:0.05-0.5 and Si:0.05-0.5, characterized in that the electrochemically active material of the negative electrode also comprises an intermetallic compound forming a hydride with hydrogen, of the compositional formula DNihd pE/sub q/ in an amount from 5 to 45% by weight calculated on the total amount of electrochemically active material, where p+q is between 4.8 and 5.4, where p is between 3.5 and 5.4, where q has a value from 0 to 1.5. D is selected from the group formed by La and Mischmetall, and E consists of one or more elements selected from the group consisting of Co, Cr, Mn and Cu.

Heuts, J.J.F.; Frens, G.

1987-10-27

12

Electrochemical cell  

SciTech Connect

A rechargeable electrochemical cell (10 in fig. 1) has a negative electrode (11) with an active surface (11') of copper; a positive electrode (12) with an active surface (12') of lead dioxide, spaced therefrom; in an aqueous acid electrolyte (13) of fluoboric, fluosilicic, sulfamic, or perchloric acid, in which both divalent copper and divalent lead ions are soluble during discharging, and from which smooth and adherent deposits may be obtained during charging; and a container (14) with an electrically nonconductive inner surface (14') that is chemically resistant to the electrolyte (13). A similar cell (30 in fig. 5) comprises also bipolar electrodes (32,31) similar in shape to the negative electrode (31) and the positive electrode (32), positioned between them and substantially parallel to them. As in fig. 2, the container may comprise a fluid-tight enclosure (24,25) with an optional pressure relief valve (28).

Schaer, G.R.

1980-05-20

13

Electrochemical cell method  

DOEpatents

A secondary electrochemical cell is prepared by providing positive and negative electrodes having outer enclosures of rigid perforated electrically conductive material defining an internal compartment containing the electrode material in porous solid form. The electrodes are each immersed in molten electrolyte salt prior to cell assembly to incorporate the cell electrolyte. Following solidification of the electrolyte substantially throughout the porous volume of the electrode material, the electrodes are arranged in an alternating positive-negative array with interelectrode separators of porous frangible electrically insulative material. The completed array is assembled into the cell housing and sealed such that on heating the solidified electrolyte flows into the interelectrode separator.

Kaun, T.D.; Eshman, P.F.

1980-05-09

14

Electrochemical Cell Assembled in Discharged State.  

National Technical Information Service (NTIS)

The patent application relates to high-temperature, secondary electrochemical cells and batteries of such cells that can be employed as power sources for electrical automobiles, hybrid electric vehicles or for the storage of energy generated during interv...

N. P. Yao W. J. Walsh

1974-01-01

15

Method of preparing electrodes with porous current collector structures and solid reactants for secondary electrochemical cells  

DOEpatents

Particulate electrode reactants, for instance transition metal sulfides for the positive electrodes and lithium alloys for the negative electrodes, are vibratorily compacted into porous, electrically conductive structures. Structures of high porosity support sufficient reactant material to provide high cell capacity per unit weight while serving as an electrical current collector to improve the utilization of reactant materials. Pore sizes of the structure and particle sizes of the reactant material are selected to permit uniform vibratory loading of the substrate without settling of the reactant material during cycling.

Gay, Eddie C. (Park Forest, IL); Martino, Fredric J. (Riverdale, IL)

1976-01-01

16

Portable electrochemical cell interrogator  

SciTech Connect

We have designed a portable electronic instrument for interrogating electrochemical cells. The instrument is powered by a 9-V battery and has an LCD digital readout. It can read out any instrument that has electrochemical cells that increase in impedance upon deplating.

Doss, J.D.; McCabe, C.W.

1984-11-01

17

Electrolyte composition for electrochemical cell  

DOEpatents

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.

Vissers, Donald R. (Naperville, IL); Tomczuk, Zygmunt (Orland Park, IL); Anderson, Karl E. (Westchester, IL); Roche, Michael F. (Downers Grove, IL)

1979-01-01

18

Separators for electrochemical cells  

SciTech Connect

An electrochemical cell is described comprising a container having two electrically isolated terminals. The container has therein an anode connected to one terminal, a cathode connected to the other terminal, a fluid electrolyte, an ionizable solute dissolved in the electrolyte, and a separator positioned between and in contact with the anode and the cathode. The separator is characterized by being a substantially continuous microporous film comprising a polymer that is a copolymer of ethylene and a fully halogenated analogue of ethylene.

Schlaikjer, C.R.

1986-12-16

19

Electrochemical Noise in Lithium Primary Cells.  

National Technical Information Service (NTIS)

Electrochemical noise is interpreted as the occurrence of microscopic fluctuations of the potential of an electrochemical cell. A study was conducted on a number of commercial lithium cells to evaluate the practicality of electrochemical noise measurement...

G. J. Donaldson W. S. Nip T. J. Patraboy J. S. Anderson M. D. Farrington

1991-01-01

20

Separator for electrochemical cells  

SciTech Connect

An electrochemical cell is described comprising a sealed casing; an anode, a cathode, a separator positioned between the anode and the cathode, and a non-aqueous electrolyte sealed in the casing; a pair of electrical terminals on the casing; means for electrically isolating the electrical terminals from each other; and means for electrically connecting the anode to one terminal and the cathode to the other terminal; wherein the anode is comprised of lithium foil, the cathode is comprised of manganese dioxide, and the separator consists essentially of a microporous polypropylene film having a thickness of about 1.5 mils and internal voids of about 60% by volume; wherein the anode, cathode, and separator are spirally wound together in a jelly roll configuration.

Griffin, R.A.

1988-12-27

21

Electrochemical photovoltaic cells and electrodes  

DOEpatents

Improved electrochemical photovoltaic cells and electrodes for use therein, particularly electrodes employing amorphous silicon or polyacetylene coating are produced by a process which includes filling pinholes or porous openings in the coatings by electrochemical oxidation of selected monomers to deposit insulating polymer in the openings.

Skotheim, Terje A. (East Patchogue, NY)

1984-01-01

22

CALORIMETRY OF OPEN ELECTROCHEMICAL CELLS  

Microsoft Academic Search

A special case of calorimetry of open electrochemical cells, that employing adiabatic enclosures, is examined. Conditions for an experimental realization of such enclosures is discussed in detail. Practi- cal arrangement and method for data collection are presented. Following the announcement by Fleischmann and Pons(1) that anomalous effects, among them excess heat generation, can be observed when deuterium is electrochemically compressed

S. Szpak; P. A. Mosier

23

Separator material for electrochemical cells.  

National Technical Information Service (NTIS)

An electrochemical cell characterized as utilizing an aramid fiber as a separator material is described. The aramid fibers are especially suited for lithium/thionyl chloride battery systems. The battery separator made of aramid fibers possesses superior m...

W. R. Cieslak L. J. Storz

1989-01-01

24

Hermetic seal for electrochemical cell  

Microsoft Academic Search

An hermetic glass-metal seal is described for an electrochemical cell having a metallic central feedthrough as a terminal thereof which is chemically incompatible with the components of said cell. The feedthrough is connected within said cell to a second compatible metallic element for electrical connection to an electrode within said cell. An inert polymeric material is sealed to the glass

P. Bro; G. Wallis

1980-01-01

25

Electrochemical cell with calcium anode  

DOEpatents

An electrochemical cell comprising a calcium anode and a suitable cathode in an alkaline electrolyte consisting essentially of an aqueous solution of an hydroxide and a chloride. Specifically disclosed is a mechanically rechargeable calcium/air fuel cell with an aqueous NaOH/NaCl electrolyte.

Cooper, John F. (Castro Valley, CA); Hosmer, Pamela K. (Tracy, CA); Kelly, Benjamin E. (Tracy, CA)

1979-01-01

26

Electrochemical cell with high conductivity glass electrolyte  

DOEpatents

A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with a ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material. 6 figs.

Nelson, P.A.; Bloom, I.D.; Roche, M.F.

1987-04-21

27

Electrochemical cell with high conductivity glass electrolyte  

DOEpatents

A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with a ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

Nelson, Paul A. (Wheaton, IL); Bloom, Ira D. (Lisle, IL); Roche, Michael F. (Glen Ellyn, IL)

1987-01-01

28

Electrochemical cell with high conductivity glass electrolyte  

DOEpatents

A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with an ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

Nelson, P.A.; Bloom, I.D.; Roche, M.F.

1986-04-17

29

Electrochemical cell with high conductivity glass electrolyte  

NASA Astrophysics Data System (ADS)

A secondary electrochemical cell with sodium-sulfur or other molten reactants is provided with an ionically conductive glass electrolyte. The cell is contained within an electrically conductive housing with a first portion at negative potential and a second portion insulated therefrom at positive electrode potential. The glass electrolyte is formed into a plurality of elongated tubes and placed lengthwise within the housing. The positive electrode material, for instance sulfur, is sealed into the glass electrolyte tubes and is provided with an elongated axial current collector. The glass electrolyte tubes are protected by shield tubes or sheets that also define narrow annuli for wicking of the molten negative electrode material.

Nelson, P. A.; Bloom, I. D.; Roche, M. F.

1986-04-01

30

Separator material for electrochemical cells  

DOEpatents

An electrochemical cell characterized as utilizing an aramid fiber as a separator material. The aramid fibers are especially suited for lithium/thionyl chloride battery systems. The battery separator made of aramid fibers possesses superior mechanical strength, chemical resistance, and is flame retardant.

Cieslak, Wendy R. (1166 Laurel Loop NE., Albuquerque, NM 87122); Storz, Leonard J. (2215 Ambassador NE., Albuquerque, NM 87112)

1991-01-01

31

Separator material for electrochemical cells  

DOEpatents

An electrochemical cell characterized as utilizing an aramid fiber as a separator material. The aramid fibers are especially suited for lithium/thionyl chloride battery systems. The battery separator made of aramid fibers possesses superior mechanical strength, chemical resistance, and is flame retardant. 1 tab.

Cieslak, W.R.; Storz, L.J.

1989-06-12

32

Electrochemical synthesis on single cells as templates.  

PubMed

The cell surface is made electrochemically active by interfacing with graphene sheets. The electrical and thermal properties of graphene allow the control of cell surface potential for electrochemical synthesis. Using this approach radially projecting ZnO nanorods are templated on the surface of single cells. This reported single cell photosensor has superior performance than similar devices made on planar surfaces. PMID:23945662

Tam, Jasper; Salgado, Shehan; Miltenburg, Mark; Maheshwari, Vivek

2013-08-29

33

Electrochemical cell having an alkali-metal-nitrate electrode  

DOEpatents

A power-producing secondary electrochemical cell includes a molten alkali metal as the negative-electrode material and a molten-nitrate salt as the positive-electrode material. The molten material in the respective electrodes are separated by a solid barrier of alkali-metal-ion conducting material. A typical cell includes active materials of molten sodium separated from molten sodium nitrate and other nitrates in mixture by a layer of sodium ..beta..'' alumina.

Roche, M.F.; Preto, S.K.

1982-06-04

34

Electrochemical corrosion of Alloy 600 in secondary water: Final report  

SciTech Connect

Electrochemical polarization measurements were conducted on Alloy 600 to screen the corrosive effects of certain PWR secondary water contaminants. These contaminants originate from resin polishing beds, condenser leakage, makeup water, and intentional additions. All additions to AVT water increased the anodic currents, but none produced any evidence of intergranular attack as determined by microscopic examination of metallographic sections after anodic polarization. Current increases were not proportional to potential changes and consequently could not be ascribed to increases in solution conductivity. Carboxylates, fluoride and bisulfate showed uniform attack. Additions of the Zn/sup + +/ cation did not cause any significant increase in anodic current over that of the accompanying acetate anion or produce any localized corrosion. Sulfate and benzosulfonate were found to cause irregular attack after anodic polarization which was changed to uniform attack in the presence of borate inhibitor. However, the anodic currents were not appreciably reduced in the presence of borate, and a strong inhibiting effect was therefore not indicated. This does not preclude the possibility of inhibition of carbon steel in tubesheet crevices with alkaline solutions. 9 refs., 15 figs., 2 tabs.

Jones, D.A.

1987-09-01

35

Electrochemical cell pressure relief devices  

SciTech Connect

A unitary end wall for an electrochemical cell container is described. The end wall comprises a central portion, encompassing the center of the wall, a peripheral portion surrounding the central portion, bridge means for connecting the central portion to the peripheral portion, one or more curved lines of frangibility and one or more pressure relief tabs remote from the center of the wall. Each pressure relief tab is bounded by one of the curved lines of frangibility extending only partially around the tab. The wall is substantially devoid of wrinkles or scores other than the one or more curved lines of frangibility. The wall is adapted to fracture along each line of frangibility upon exposure to a pressure above a predetermined limit so that each pressure relief tab can bend away from the remainder of the wall and provide an opening for relief of the pressure remote from the center of the wall. The bridge means is operative to retain the central portion in place relative to the peripheral portion upon fracture of the wall along the one or more lines of frangibility.

Marchak, G.E.

1988-02-02

36

Nanodisperse transition metal electrodes (NTME) for electrochemical cells  

DOEpatents

Disclosed are transition metal electrodes for electrochemical cells using gel-state and solid-state polymers. The electrodes are suitable for use in primary and secondary cells. The electrodes (either negative electrode or positive electrode) are characterized by uniform dispersion of the transition metal at the nanoscale in the polymer. The transition metal moiety is structurally amorphous, so no capacity fade should occur due to lattice expansion/contraction mechanisms. The small grain size, amorphous structure and homogeneous distribution provide improved charge/discharge cycling performance, and a higher initial discharge rate capability. The cells can be cycled at high current densities, limited only by the electrolyte conductivity. A method of making the electrodes (positive and negative), and their usage in electrochemical cells are disclosed.

Striebel, Kathryn A.; Wen, Shi-Jie

1998-12-01

37

Textbook Error: Short Circuiting on Electrochemical Cell  

ERIC Educational Resources Information Center

|Short circuiting an electrochemical cell is an unreported but persistent error in the electrochemistry textbooks. It is suggested that diagrams depicting a cell delivering usable current to a load be postponed, the theory of open-circuit galvanic cells is explained, the voltages from the tables of standard reduction potentials is calculated and…

Bonicamp, Judith M.; Clark, Roy W.

2007-01-01

38

Electrochemical noise in lithium primary cells  

NASA Astrophysics Data System (ADS)

Electrochemical noise is interpreted as the occurrence of microscopic fluctuations of the potential of an electrochemical cell. A study was conducted on a number of commercial lithium cells to evaluate the practicality of electrochemical noise measurement as a diagnostic tool for performance and/or safety. The survey was limited to the following lithium based systems: sulfur dioxide, thionyl chloride, and manganese dioxide. The cells were subjected to a program of storage, environmental, and discharge conditions and then examined to determine whether there was any detectable effect on the electrochemical noise characteristics. While the study was of limited scope, it was nevertheless established that all cells exhibited some measurable electrochemical noise under certain conditions. The characteristics of the noise and its magnitude were influenced by many factors. The occurrence of observable noise above the instrumental background was generally associated with cells which had been discharged to between 80 and 100 percent of their nominal capacity. Most of the noise of interest was found at frequencies below 100 Hz.

Donaldson, George J.; Nip, Wing S.; Patraboy, Timothy J.; Anderson, James S.; Farrington, Michael D.

39

Gas recombination assembly for electrochemical cells  

DOEpatents

An assembly for recombining gases generated in electrochemical cells wherein a catalyst strip is enveloped within a hydrophobic, gas-porous film which, in turn, is encased between gas-porous, metallic layers. The sandwich construction of metallic layers and film is formed into a spiral with a tab for connection to the cell.

Levy, Isaac (New Fairfield, CT); Charkey, Allen (Brookfield, CT)

1989-01-01

40

Heteroatom incorporated coke for electrochemical cell electrode  

DOEpatents

This invention relates to an electrode for a coke/alkali metal electrochemical cell comprising: (a) calcined coke particles: (i) that contain at least 0.5 weight percent of nitrogen heteroatoms and at least 1.0 weight percent sulfur heteroatoms, and (ii) that have an average particle size from 2 microns to 40 microns with essentially no particles being greater than 50 microns. (b) a binder This invention also relates to a coke/alkali metal electrochemical cell comprising: (a) an electrode as described above, (b) a non-aqueous electrolytic solution comprising an organic aprotic solvent and an electrically conductive salt, and (c) a counterelectrode.

Lewis, Irwin Charles (Strongsville, OH); Greinke, Ronald Alfred (Medina, OH)

1997-01-01

41

Method of constructing an improved electrochemical cell  

DOEpatents

An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

Grimes, Patrick G. (Westfield, NJ); Einstein, Harry (Springfield, NJ)

1984-10-09

42

Intrinsic coherence resonance in an electrochemical cell.  

PubMed

We study the interaction of intrinsic electrochemical noise with autonomous nonlinear dynamics of a three-electrode electrochemical cell. The amplitude of this intrinsic (internal) noise, regulated by the concentration of chloride ions, is monotonically increased and the provoked dynamics is analyzed. The experimentally constructed coherence factor beta versus the concentration of the chloride ions' curve has a unimodal shape indicating the emergence of intrinsic coherence resonance. The abscissa for the maxima of this unimodal curve corresponds to the optimum value of intrinsic noise where maximum regularity of the invoked dynamics is observed. PMID:16241398

Rivera, M; Escalera Santos, Gerardo J; Uruchurtu-Chavarín, J; Parmananda, P

2005-09-16

43

Intrinsic coherence resonance in an electrochemical cell  

NASA Astrophysics Data System (ADS)

We study the interaction of intrinsic electrochemical noise with autonomous nonlinear dynamics of a three-electrode electrochemical cell. The amplitude of this intrinsic (internal) noise, regulated by the concentration of chloride ions, is monotonically increased and the provoked dynamics is analyzed. The experimentally constructed coherence factor ? versus the concentration of the chloride ions’ curve has a unimodal shape indicating the emergence of intrinsic coherence resonance. The abscissa for the maxima of this unimodal curve corresponds to the optimum value of intrinsic noise where maximum regularity of the invoked dynamics is observed.

Rivera, M.; Santos, Gerardo J. Escalera; Uruchurtu-Chavarín, J.; Parmananda, P.

2005-09-01

44

Electrolyte for an electrochemical cell  

DOEpatents

Described is a thin-film battery, especially a thin-film microbattery, and a method for making the same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte amorphous lithium phosphorus oxynitride which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between {minus}15 C and 150 C. 9 figs.

Bates, J.B.; Dudney, N.J.

1997-01-28

45

Cathode for an electrochemical cell  

DOEpatents

Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode. Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between -15.degree. C. and 150.degree. C.

Bates, John B. (Oak Ridge, TN); Dudney, Nancy J. (Knoxville, TN); Gruzalski, Greg R. (Oak Ridge, TN); Luck, Christopher F. (Knoxville, TN)

2001-01-01

46

Bacteriorhodopsin-based photo-electrochemical cell  

Microsoft Academic Search

A simple solution-based electrochemical cell has been constructed and successfully employed in the detection of the photoelectric response upon photoexcitation of bacteriorhodopsin (bR) without external bias. Commercially-available indium tin oxide (ITO) glasses served as the optical windows and electrodes. Small amounts of bR suspensions (?100?L) were utilized as the photovoltaic medium to generate the proton gradient between two half-cells separated

Li-Kang Chu; Chun-Wan Yen; Mostafa A. El-Sayed

2010-01-01

47

Method of making electrodes for electrochemical cell  

DOEpatents

A method of making an electrode for an electrochemical cell in which particulate electrode-active material is mixed with a liquid organic carrier chemically inert with respect to the electrode-active material, mixing the liquid carrier to form an extrudable slurry. The liquid carrier is present in an amount of from about 10 to about 50 percent by volume of the slurry, and then the carrier is removed from the slurry leaving the electrode-active material.

Kaun, Thomas D. (New Lenox, IL); Kilsdonk, Dennis J. (Joliet, IL)

1983-01-01

48

Electrochemical cell with a cadmium patch electrode  

SciTech Connect

A cadmium patch laminar electrode, comprising a dispersion of particulate cadmium in a binder matrix on a conductive plastic substrate is prepared by contacting a zinc patch electrode comprising a dispersion of particulate zinc in a binder matrix on a conductive plastic substrate with an aqueous solution of a cadmium salt. The cadmium patch electrode can be used in a primary electrochemical cell such as that employing a manganese dioxide cathode and a cadmium chloride electrolyte.

Ames, A.E.; Bloom, S.M.; Hoffman, A.; Norland, K.

1980-01-22

49

Magnesium/manganese dioxide electrochemical cell  

SciTech Connect

This patent describes an improvement in a magnesium/manganese dioxide electrochemical cell that has been stored following partial usage and including an alloy of magnesium as the anode, a moist cathode mix of carbon black, manganese dioxide, magnesium hydroxide, barium chromate and lithium chromate as the cathode, and 3.5 to 4.0 normal magnesium perchlorate as the electrolyte. The improvement involves increasing the moisture content of the cathode mix from 34 to 38 percent at the time of making the cell to reduce the self discharge and increase the operating capacity after the cell has been stored following partial usage.

Jarvis, L.P.; Brundage, M.T.; Atwater, T.B.

1989-09-26

50

Porous electronic current collector bodies for electrochemical cell configurations  

DOEpatents

A high-temperature, solid electrolyte electrochemical cell configuration is made comprising a plurality of elongated electrochemical cells 1, having inner electrodes 3, outer electrodes 6 and solid electrolyte 4 therebetween, the cells being electronically connected in series and parallel by flexible, porous, fibrous strips 7, where the strips contain flexible, electronically conductive fibers bonded together and coated with a refractory oxide, and where the oxide coating is effective to prevent additional bonding of fibers during electrochemical cell operation at high temperatures.

Pollack, William (Pittsburgh, PA); Reichner, Philip (Plum Borough, PA)

1989-01-01

51

Overcharge Protection for Electrochemical Cells.  

National Technical Information Service (NTIS)

The invention relates to an improvement in a cell which is normally susceptible to damage from overcharging comprised of a negative electrode, a positive electrode, and an electrolyte comprised of an overcharge protection salt carried in a carrier or solv...

B. K. Peterson G. Dantsin J. Liu K. Amine K. Jambunathan

2005-01-01

52

Electrochemical characteristics of lithium-ion cells  

SciTech Connect

The authors describe below the electrochemical performance characteristics, including charge-discharge characteristics at different rates, of cylindrical 18650 (18 mm diameter, 65 mm high) and prismatic lithium ion cells at ambient and sub-ambient temperatures. Ragone plots of power and energy data for these cells are compared and indicate that at room temperature the prismatic lithium ion cells (approx. 500 mAh) exhibit higher specific power and power density than the 18650 cells (approx. 1,100 mAhr). The cell impedance was measured between 35 C and {minus}40 C at three open circuit voltages: 4.1 v (fully charged), 3.6 v (partially discharged), and 3.1 v (almost completely discharged). Over the temperature range from 35 C to {minus}20 C, the cell impedance is nearly constant for both cell types and increases by 2 to 3 times at {minus}40 C. The impedance doesn`t vary significantly with open circuit voltage (OCV). These cells show very little voltage drop at room temperature for current pulses up to 1 A. The charge-discharge characteristics of the cells are being studied at different rates as a function of temperature to compute the power, energy, and capacity outputs. This will not only broaden the database on lithium ion cells, but will also allow us to evaluate the suitability of the cells as power sources for low temperature applications. Other electrochemical characteristics of these cells including pulse response are being evaluated. Impedance measurements of the cells under load are planned to make meaningful correlations between the voltage drop and the current pulse amplitude.

Nagasubramanian, C.; Roth, P.; Jungst, R.G.; Clark, N.

1998-01-01

53

Electrochemical cell having internal short inhibitor  

SciTech Connect

An electrochemical cell comprises a spirally wound assembly, the assembly including a negative plate; a porous polyester layer disposed on each major surface of the negative plate; a porous, electrically non-conductive separator disposed on each of the polyester layers; and a positive plate disposed on one of the separators. The cell further includes a housing for enclosing the assembly and an electrolyte such that the electrolyte comes in contact with the plates, polyester layers and separators. The housing includes a pair of external terminals each of which being connected to one of the plates.

Hooke, J.W.

1984-04-24

54

Frequency response of electrochemical cells  

NASA Astrophysics Data System (ADS)

The main objective was to examine the feasibility of using frequency response techniques (1) as a tool in destructive physical analysis of batteries, particularly for estimating electrode structural parameters such as specific area, porosity, and tortuosity and (2) as a non-destructive testing technique for obtaining information such as state of charge and acceptability for space flight. The phenomena that contribute to the frequency response of an electrode include: (1) double layer capacitance; (2) Faradaic reaction resistance; (3) mass transfer of Warburg impedance; and (4) ohmic solution resistance. Nickel cadmium cells were investigated in solutions of KOH. A significant amount of data was acquired. Quantitative data analysis, using the developed software, is planned for the future.

Thomas, Daniel L.

1990-10-01

55

Electrochemical and quartz microbalance technique studies of anode material for secondary lithium batteries  

Microsoft Academic Search

The lithium metal anode for secondary lithium batteries was studied using the electrochemical and the quartz crystal microbalance (QCM) techniques. The solutions studied were: (i) propylene carbonate (PC) containing LiClO4, and (ii) ?-butyrolactone (?-BL) containing LiPF6. Surface film formation on the electrodes in these solutions was investigated during galvanostatic electrodeposition of lithium. Moreover, the influence of the surface films upon

Shinji Koike; Takuya Fujieda; Noboru Wakabayashi; Shunichi Higuchi

1997-01-01

56

Organic electrolyte for use in a lithium rechargeable electrochemical cell and lithium rechargeable electrochemical cell including said organic electrolyte  

SciTech Connect

This invention relates in general to use of an organic electrolyte in a lithium rechargeable electrochemical cell and to a lithium rechargeable electrochemical cell including said electrolyte; and, in particular, to the use of 1 to 2 mol/dm/sup 3/ LiAsF/sub 6/ in dimethylcarbonate (DMC) or 1 to 2 mol/dm/sup 3/ LiAsF/sub 6/ in (DMC) mixtures with methyl formate (MF) in which the mass percent of the (DMC) can vary from 25 to 100 mass percent as the electrolyte in a lithium rechargeable electrochemical cell, and to a lithium rechargeable electrochemical cell including said electrolyte.

Plichta, E.J.; Slane, S.M.; Salomon, M.

1987-07-06

57

Solid oxide electrochemical cell fabrication process  

DOEpatents

A method to form an electrochemical cell (12) is characterized by the steps of thermal spraying stabilized zirconia over a doped lanthanum manganite air electrode tube (14) to provide an electrolyte layer (15), coating conductive particles over the electrolyte, pressurizing the outside of the electrolyte layer, feeding halide vapors of yttrium and zirconium to the outside of the electrolyte layer and feeding a source of oxygen to the inside of the electrolyte layer, heating to cause oxygen reaction with the halide vapors to close electrolyte pores if there are any and to form a metal oxide coating on and between the particles and provide a fuel electrode (16).

Dollard, Walter J. (Churchill Borough, PA); Folser, George R. (Lower Burrell, PA); Pal, Uday B. (Cambridge, MA); Singhal, Subhash C. (Murrysville, PA)

1992-01-01

58

Sensor apparatus using an electrochemical cell  

DOEpatents

A novel technology for sensing mechanical quantities such as force, stress, strain, pressure and acceleration has been invented. This technology is based on a change in the electrochemically generated voltage (electromotive force) with application of force, stress, strain, pressure or acceleration. The change in the voltage is due to a change in the internal resistance of the electrochemical cell with a change in the relative position or orientation of the electrodes (anode and cathode) in the cell. The signal to be detected (e.g. force, stress, strain, pressure or acceleration) is applied to one of the electrodes to cause a change in the relative position or orientation between the electrodes. Various materials, solid, semisolid, gel, paste or liquid can be utilized as the electrolyte. The electrolyte must be an ion conductor. The examples of solid electrolytes include specific polymer conductors, polymer composites, ion conducting glasses and ceramics. The electrodes are made of conductors such as metals with dissimilar electronegativities. Significantly enhanced sensitivities, up to three orders of magnitude higher than that of comparable commercial sensors, are obtained. The materials are substantially less expensive than commercially used materials for mechanical sensors.

Thakur, Mrinal (1309 Gatewood Dr., Apt. 1703, Auburn, AL 36830)

2002-01-01

59

A Model Approach to the Electrochemical Cell: An Inquiry Activity  

ERIC Educational Resources Information Center

|In an attempt to address some student misconceptions in electrochemistry, this guided-inquiry laboratory was devised to give students an opportunity to use a manipulative that simulates the particulate-level activity within an electrochemical cell, in addition to using an actual electrochemical cell. Students are led through a review of expected…

Cullen, Deanna M.; Pentecost, Thomas C.

2011-01-01

60

Thermodynamic and Kinetic Properties of the Electrochemical Cell.  

ERIC Educational Resources Information Center

|Describes basic characteristics of the electrochemical cell. Also describes basic principles of electrochemical procedures and use of these concepts to explain use of the term "primarily" in discussions of methods primarily responsive to equilibrium cell potential, bulk ohmic resistance, and the Faradaic impedance. (JN)|

Smith, Donald E.

1983-01-01

61

Thermal regeneration of an electrochemical concentration cell  

DOEpatents

A system and method for thermally regenerating an electrochemical concentration cell having first and second aluminum electrodes respectively positioned in contact with first and second electrolytes separated by an ion exchange member, the first and second electrolytes being composed of different concentrations of an ionic solvent and a salt, preferably an aluminum halide. The ionic solvent may be either organic or inorganic with a relatively low melting point, the ionic solvent and the salt form a complex wherein the free energy of formation of said complex is less than about -5 Kcal/mole. A distillation column using solar heat or low grade industrial waste heat receives the first and second electrolytes and thermally decomposes the salt-solvent complex to provide feed material for the two half cells.

Krumpelt, Michael (Naperville, IL); Bates, John K. (Plainfield, IL)

1981-01-01

62

Thermal regeneration of an electrochemical concentration cell  

DOEpatents

A system and method are described for thermally regenerating an electrochemical concentration cell having first and second aluminum electrodes respectively positioned in contact with first and second electrolytes separated by an ion exchange member, the first and second electrolytes being composed of different concentrations of an ionic solvent and a salt, preferably an aluminum halide. The ionic solvent may be either organic or inorganic with a relatively low melting point, the ionic solvent and the salt form a complex wherein the free energy of formation of said complex is less than about -5 kcal/mole. A distillation column using solar heat or low grade industrial waste heat receives the first and second electrolytes and thermally decomposes the salt-solvent complex to provide feed material for the two half cells.

Krumpelt, M.; Bates, J.K.

1980-05-09

63

Electrochemical cell and negative electrode therefor. [Li-Al anode  

DOEpatents

A secondary electrochemical cell is described with the positive and negative electrodes separated by a molten salt electrolyte with the negative electrode comprising a particulate mixture of lithium-aluminum alloy and electrolyte and an additive selected from graphitized carbon, Raney iron or mixtures thereof. The lithium-aluminum alloy is present in the range of from about 45 to about 80% by volume of the negative electrode, and the electrolyte is present in an amount not less than about 10% by volume of the negative electrode. The additive of graphitized carbon is present in the range of from about 1 to about 10% by volume of the negative electrode, and the Raney iron additive is present in the range of from about 3 to about 10% by volume of the negative electrode.

Kaun, T.D.

1981-07-29

64

A high temperature molten salt thermal electrochemical cell  

NASA Astrophysics Data System (ADS)

This invention relates in general to a high temperature molten salt thermal electrochemical cell and in particular to such a cell including cobalt oxide (Co3O4) as the cathode material. High temperature molten salt thermal electrochemical cells are widely used as power sources for projectiles, rockets, bombs, mines, missiles, decoys, jammers, and torpedoes. These are also used as fuses. Thermal electrochemical cells are reserve-type cells that can be activated by heating with a pyrotechnic heat source such as zirconium and barium chromate powders or mixtures of iron powder and potassium perchlorate.

Plichta, Edward J.; Behl, Wishvender K.

1990-02-01

65

New materials for electrochemical cells. Final report  

SciTech Connect

Determination of the thermochemical, structural and basic electrochemical properties of mixed electronic/ionic conductors was successfully carried out on the following systems: H(x)MoO3, Li(x)V2O5, H(x)WO3, and Li(x)MoO3. Attempts to design new protonic and Li(+)ion conductors have opened up two fields: One is the recognition of particle hydrates as protonic electrolytes capable of fabrication into dense ceramics by cold pressing; we have obtained room-temperature H(+)ion conductivity approaching .01/ohm/cm in cold-pressing Sb(.2)O(5.5).4H2O. The other is the use of low-temperature chemical and electrochemical techniques to prepare new materials not attainable with high-temperature techniques. With this method we have prepared Li/Li (1-x) Cobalt dioxide cells having open-circuit voltages in excess of 4 V. We have also initiated studies into composite electrolyte/electrode materials using room-temperature molten salts immobilized by insertion-compound electrode materials.

Goodenough, J.B.; Dickens, P.G.

1981-12-31

66

Composite electrode for use in electrochemical cells  

DOEpatents

A porous composite electrode for use in electrochemical cells. The electrode has a first face and a second face defining a relatively thin section therebetween. The electrode is comprised of an ion conducting material, an electron conducting material, and an electrocatalyst. The volume concentration of the ion conducting material is greatest at the first face and is decreased across the section, while the volume concentration of the electron conducting material is greatest at the second face and decreases across the section of the electrode. Substantially all of the electrocatalyst is positioned within the electrode section in a relatively narrow zone where the rate of electron transport of the electrode is approximately equal to the rate of ion transport of the electrode. 4 figs., 1 tab.

Vanderborgh, N.E.; Huff, J.R.; Leddy, J.

1987-10-16

67

Electrochemical doping during light emission in polymer light-emitting electrochemical cells  

NASA Astrophysics Data System (ADS)

Polymer light-emitting electrochemical cells (LECs), the electrochemical analog of light-emitting diodes, are relatively simple to manufacture yet difficult to understand. The combination of ionic and electronic charge carriers make for a richly complex electrochemical device. This paper addresses two curious observations from wide-gap planar LEC experiments: (1) Both the current and light intensity continue to increase with time long after the p-n junction has formed. (2) The light-emitting p-n junction often moves, both “straightening out” and migrating toward the cathode, with time. We propose that these phenomena are explained by the continuation of electrochemical doping even after the p-n junction has formed. We hope that this understanding will help to solve issues such as the limited lifetime of LECs and will help to make them a more practical device in commercial and scientific applications.

Robinson, Nathaniel D.; Fang, Junfeng; Matyba, Piotr; Edman, Ludvig

2008-12-01

68

Method for making an electrochemical cell  

DOEpatents

An electrochemical device is described including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is provided. 17 figs.

Tuller, H.L.; Kramer, S.A.; Spears, M.A.; Pal, U.B.

1996-04-23

69

Method for the manufacture of an electrochemical cell or battery and battery made by the method  

SciTech Connect

The invention relates to a method for the manufacture of an electrochemical cell or battery, consisting of a stack of plateshaped elements, each of which consists of a sheet or plate of electrode material which is mounted in a frame made of electrically insulating fibrous-web material impregnated with a non-polymerized thermosetting synthetic material, which elements in a first compression molding stage are heated under pressure for a relatively short primary time at a relatively low primary temperature under which conditions the thermosetting synthetic material flows well but polymerizes only to a minor degree, thereafter the elements are combined with other battery components and stacked into an electrochemical cell package which in a second compression molding stage is formed into a coherent block by compression for a relatively long secondary time and at a relatively high secondary temperature to set the thermosetting synthetic material.

Dorrestijn, A.

1980-11-11

70

Transient Behavior of Light-Emitting Electrochemical Cells.  

National Technical Information Service (NTIS)

Recent prototypes of the individual identification friend or foe (IIFF) patch use a light-emitting electrochemical cell (LEC) as the emitter. This research characterizes the transient behavior of LEC's by measuring transient capacitance. The transient cap...

Y. A. Davis

2011-01-01

71

Thermal conductor for high-energy electrochemical cells  

DOEpatents

A thermal conductor for use with an electrochemical energy storage device is disclosed. The thermal conductor is attached to one or both of the anode and cathode contacts of an electrochemical cell. A resilient portion of the conductor varies in height or position to maintain contact between the conductor and an adjacent wall structure of a containment vessel in response to relative movement between the conductor and the wall structure. The thermal conductor conducts current into and out of the electrochemical cell and conducts thermal energy between the electrochemical cell and thermally conductive and electrically resistive material disposed between the conductor and the wall structure. The thermal conductor may be fabricated to include a resilient portion having one of a substantially C-shaped, double C-shaped, Z-shaped, V-shaped, O-shaped, S-shaped, or finger-shaped cross-section. An elastomeric spring element may be configured so as to be captured by the resilient conductor for purposes of enhancing the functionality of the thermal conductor. The spring element may include a protrusion that provides electrical insulation between the spring conductor and a spring conductor of an adjacently disposed electrochemical cell in the presence of relative movement between the cells and the wall structure. The thermal conductor may also be fabricated from a sheet of electrically conductive material and affixed to the contacts of a number of electrochemical cells.

Hoffman, Joseph A. (Minneapolis, MN); Domroese, Michael K. (South St. Paul, MN); Lindeman, David D. (Hudson, WI); Radewald, Vern E. (Austin, TX); Rouillard, Roger (Beloeil, CA); Trice, Jennifer L. (Eagan, MN)

2000-01-01

72

Mutations of the secondary cell wall  

Microsoft Academic Search

It has not been possible to isolate a number of crucial enzymes involved in plant cell wall synthesis. Recent progress in identifying some of these steps has been overcome by the isolation of mutants defective in various aspects of cell wall synthesis and the use of these mutants to identify the corresponding genes. Secondary cell walls offer numerous advantages for

Simon R. Turner; Neil Taylor; Louise Jones

2001-01-01

73

Steel refining with an electrochemical cell  

DOEpatents

Apparatus is described for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight oxygen and not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom. 2 figs.

Blander, M.; Cook, G.M.

1988-05-17

74

Steel refining with an electrochemical cell  

DOEpatents

Disclosed is an apparatus for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom.

Blander, M.; Cook, G.M.

1985-05-21

75

Steel refining with an electrochemical cell  

DOEpatents

Apparatus for processing a metallic fluid containing iron oxide, container for a molten metal including an electrically conductive refractory disposed for contact with the molten metal which contains iron oxide, an electrolyte in the form of a basic slag on top of the molten metal, an electrode in the container in contact with the slag electrically separated from the refractory, and means for establishing a voltage across the refractory and the electrode to reduce iron oxide to iron at the surface of the refractory in contact with the iron oxide containing fluid. A process is disclosed for refining an iron product containing not more than about 10% by weight oxygen and not more than about 10% by weight sulfur, comprising providing an electrolyte of a slag containing one or more of calcium oxide, magnesium oxide, silica or alumina, providing a cathode of the iron product in contact with the electrolyte, providing an anode in contact with the electrolyte electrically separated from the cathode, and operating an electrochemical cell formed by the anode, the cathode and the electrolyte to separate oxygen or sulfur present in the iron product therefrom.

Blander, Milton (Palos Park, IL); Cook, Glenn M. (Naperville, IL)

1988-01-01

76

Method of doping interconnections for electrochemical cells  

DOEpatents

A dense, electronically conductive interconnection layer 26 is bonded on a porous, tubular, electronically conductive air electrode structure 16, optionally supported by a ceramic support 22, by (A) forming a layer of oxide particles of at least one of the metals Ca, Sr, Co, Ba or Mg on a part 24 of a first surface of the air electrode 16, (B) heating the electrode structure, (C) applying a halide vapor containing at least lanthanum halide and chromium halide to the first surface and applying a source of oxygen to a second opposite surface of the air electrode so that they contact at said first surface, to cause a reaction of the oxygen and halide and cause a dense lanthanum-chromium oxide structure to grow, from the first electrode surface, between and around the oxide particles, where the metal oxide particles get incoporated into the lanthanum-chromium oxide structure as it grows thicker with time, and the metal ions in the oxide particles diffuse into the bulk of the lanthamum-chromium oxide structure, to provide a dense, top, interconnection layer 26 on top of the air electrode 16. A solid electrolyte layer 18 can be applied to the uncovered portion of the air electrode, and a fuel electrode 20 can be applied to the solid electrolyte, to provide an electrochemical cell 10.

Pal, Uday B. (Monroeville, PA); Singhal, Subhash C. (Murrysville, PA); Moon, David M. (Pittsburgh, PA); Folser, George R. (Lower Burrell, PA)

1990-01-01

77

Quantum Dot Light-emitting Electrochemical Cells  

NASA Astrophysics Data System (ADS)

Semiconducting polymers have enormous potential to expand the applications of electronic and optoelectronic technologies. While polymer optoelectronic devices have been successful, they typically suffer from poor performance and stability. Quantum dots (QDs) boast size-tunable band-gap energies and improved stability over organic emitters , but their efficacy in a typical hybrid LED structure is limited by an insulating surface ligand layer that increases the charge tunneling barrier and leads to unwanted emission from the polymer host. Typically, hybrid LEDs are constructed with a monolayer of QDs in order to overcome this limitation. A polymer light-emitting electrochemical cell (LEC) structure, however, presents an alternative solution by limiting the thickness of the emissive region of the polymer/QD film. Emission spectra of novel LEC structures incorporating QDs as the active emitter show better color purity than polymer-only devices, as well as pure emission from the QDs, regardless of operation voltage. This device structure has the potential to improve a number of issues currently limiting the performance of polymer based optoelectronic devices.

Norell Bader, Amanda; Leger, Janelle

2010-03-01

78

Cell structure for electrochemical devices and method of making same  

DOEpatents

An electrochemical device comprises a plurality of cells, each cell including a laminate cell membrane, made up of a separator/electrolyte means interposed between alternating positive and negative electrodes, each type of electrode being respectively in common contact to a single current collector.

Kaun, Thomas D. (320 Willow St., New Lenox, IL 60451)

1993-01-01

79

An electrochemical surface plasmon resonance imaging system targeting cell analysis  

NASA Astrophysics Data System (ADS)

This paper presents an electrochemical-surface plasmon resonance imaging (EC-SPRI) system, enabling the characterization of optical and electrical properties of cells, simultaneously. The developed surface plasmon resonance (SPR) imaging system was capable of imaging micro cavities with a dimension of 10 ?m × 10 ?m and differentiated glycerol solutions with a group of refractive indices (RIs). Furthermore, the EC-SPRI system was used to image A549 cells, suggesting corresponding RI and morphology changes during the cell death process. In the end, electrochemical and SPR methods were used in combination, recording oxidation peaks of A549 cells in the cyclic voltage curves and SPR response unit increase, simultaneously.

Zhang, L. L.; Chen, X.; Wei, H. T.; Li, H.; Sun, J. H.; Cai, H. Y.; Chen, J. L.; Cui, D. F.

2013-08-01

80

Wick-and-pool electrodes for electrochemical cell  

SciTech Connect

An electrode system includes a reservoir of liquid-metal reactant, and a wick extending from a submersed location within the reservoir into the molten electrolyte of an electrochemical cell structure. The wick is flooded with the liquid metal and thereby serves as one electrode within the cell. This electrode system has application in high-temperature batteries employing molten alkali metals or their alloys as active material within an electrode submersed within a molten salt electrolyte. It also can be used in electrochemical cells where the purification, separation or electrowinning of liquid metals is accomplished. 4 figs.

Roche, M.F.; Faist, S.M.; Eberhart, J.G.; Ross, L.E.

1980-09-02

81

Electrochemical cell for in-situ x-ray characterization  

SciTech Connect

An electrochemical cell suitable for in-situ XRD analysis is presented. Qualitative information such as phase formation and phase stability can be easily monitored using the in-situ cell design. Quantitative information such as lattice parameters and kinetic behavior is also straightforward. Analysis of the LiMn&sub2;O&sub4; spinel using this cell design shows that the lattice undergoes two major structural shrinkages at approx. 4.0 V and approx. 4.07 V during charging. These shrinkages correlate well with the two electrochemical waves observed and indicate the likelihood of two separate redox processes which charging and discharging.

Doughty, D.H.; Ingersoll, D.; Rodriguez, M.A.

1998-08-04

82

The Variation of Electrochemical Cell Potentials with Temperature  

ERIC Educational Resources Information Center

|Electrochemical cell potentials have no simple relationship with temperature but depend on the interplay between the sign and magnitude of the isothermal temperature coefficient, dE[degrees]/dT, and on the magnitude of the reaction quotient, Q. The variations in possible responses of standard and non-standard cell potentials to changes in the…

Peckham, Gavin D.; McNaught, Ian J.

2011-01-01

83

Electrochemical characteristics of acid electrolytes for fuel cells  

NASA Astrophysics Data System (ADS)

Five topics investigated by the Gas Research Institute (GRI) contractors at Case Western Reserve University (CWRU) during the past year included: (1) electrochemical evaluation of perfluorinated electrolyte, (2) the Nafion solid polymer electrolyte (SPE) fuel cell, (3) electrochemistry of single crystal Pt electrodes in acid solution, (4) catalytic effects of adatoms entrapped on electrode surfaces by bipolar or monopolar ion exchange membrane layers, (5) investigations of the Fleischmann-Pons phenomenon. The principal objective of the project is to evaluate new acid electrolytes. Electrochemical evaluation was made for two bisphosphonic acids as a replacement for phosphoric acid as a fuel cell electrolyte, and also a bis-sulfonyl carbon acid as an additive to concentrated phosphoric acid electrolyte for acid H2-O2 fuel cells. Electrochemical characteristics were found for these new perfluorinated acids.

Adzic, R.; Gervasio, D.; Kanamura, K.; Razaq, A.; Razaq, M.; Yeager, Ernest B.

1990-01-01

84

Systems, methods and computer-readable media for modeling cell performance fade of rechargeable electrochemical devices  

DOEpatents

A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware periodically samples performance characteristics of the electrochemical cell. The computing system determines cell information from the performance characteristics of the electrochemical cell. The computing system also develops a mechanistic level model of the electrochemical cell to determine performance fade characteristics of the electrochemical cell and analyzing the mechanistic level model to estimate performance fade characteristics over aging of a similar electrochemical cell. The mechanistic level model uses first constant-current pulses applied to the electrochemical cell at a first aging period and at three or more current values bracketing a first exchange current density. The mechanistic level model also is based on second constant-current pulses applied to the electrochemical cell at a second aging period and at three or more current values bracketing the second exchange current density.

Gering, Kevin L

2013-08-27

85

Secondary Signet Ring Cell Carcinoma of Prostate  

PubMed Central

True metastases to prostate from solid tumors are reported only in 0.2% of all surgical prostatic specimens and 2.9% of all male postmortems. Clinical context, morphological features, and immunohistochemical localization of prostate specific antigen (PSA) are supposed to clarify the differential diagnosis between a secondary and a primary tumor. We report an unusual and rare case of secondary signet ring cell carcinoma (SRCC) of prostate in which the clinical data and signet ring cell morphology pointed toward the diagnosis of a primary SRCC. Immunohistochemistry (IHC) for PSA not only proved the case to be a secondary SRCC but also initiated the process for diagnosis of the occult primary malignancy in the patient?s stomach.

Khan, Kalyan; Bandyopadhyay, Arghya; Gangopadhyay, Mimi; Chakraborty, Subrata; Bera, Pranati

2012-01-01

86

Method of enhancing the wettability of boron nitride for use as an electrochemical cell separator  

DOEpatents

A felt or other fabric of boron nitride suitable for use as an interelecte separator within an electrochemical cell is wetted with a solution containing a thermally decomposable organic salt of an alkaline earth metal. An aqueous solution of magnesium acetate is the preferred solution for this purpose. After wetting the boron nitride, the solution is dried by heating at a sufficiently low temperature to prevent rapid boiling and the creation of voids within the separator. The dried material is then calcined at an elevated temperature in excess of 400.degree. C. to provide a coating of an oxide of magnesium on the surface of the boron nitride fibers. A fabric or felt of boron nitride treated in this manner is easily wetted by molten electrolytic salts, such as the alkali metal halides or alkaline earth metal halides, that are used in high temperature, secondary electrochemical cells.

McCoy, Lowell R. (Woodland Hills, CA)

1982-01-01

87

Method of enhancing the wettability of boron nitride for use as an electrochemical cell separator  

DOEpatents

A felt or other fabric of boron nitride suitable for use as an interelectrode separator within an electrochemical cell is wetted with a solution containing a thermally decomposable organic salt of an alkaline earth metal. An aqueous solution of magnesium acetate is the preferred solution for this purpose. After wetting the boron nitride, the solution is dried by heating at a sufficiently low temperature to prevent rapid boiling and the creation of voids within the separator. The dried material is then calcined at an elevated temperature in excess of 400/sup 0/C to provide a coating of an oxide of magnesium on the surface of the boron nitride fibers. A fabric or felt of boron nitride treated in this manner is easily wetted by molten electrolytic salts, such as the alkali metal halides or alkaline earth metal halides, that are used in high temperature, secondary electrochemical cells.

McCoy, L.R.

1981-01-23

88

Continuous-feed electrochemical cell with nonpacking particulate electrode  

DOEpatents

An electrochemical cell providing full consumption of electrochemically active particles in a nonpacking, electrolyte-permeable bed has a tapered cell cavity bounded by two nonparallel surfaces separated by a distance that promotes bridging of particles across the cavity. The gap/particle size ratio is maintained as the particles are consumed, decrease in size, and travel from the point of entry to the narrower end of the cell. A cell of this configuration supports a bed of low packing density maintained in a dynamic steady state by alternate formation and collapse of particle bridges across the gap and associated voids over the entire active area of the cell. The cell design can be applied to refuelable zinc/air cells and zinc/ferrocyanide storage batteries.

Cooper, John F. (Oakland, CA)

1995-01-01

89

Continuous-feed electrochemical cell with nonpacking particulate electrode  

DOEpatents

An electrochemical cell providing full consumption of electrochemically active particles in a nonpacking, electrolyte-permeable bed has a tapered cell cavity bounded by two nonparallel surfaces separated by a distance that promotes bridging of particles across the cavity. The gap/particle size ratio is maintained as the particles are consumed, decrease in size, and travel from the point of entry to the narrower end of the cell. A cell of this configuration supports a bed of low packing density maintained in a dynamic steady state by alternate formation and collapse of particle bridges across the gap and associated voids over the entire active area of the cell. The cell design can be applied to refuelable zinc/air cells and zinc/ferrocyanide storage batteries. 6 figs.

Cooper, J.F.

1995-07-18

90

Topographical and electrochemical nanoscale imaging of living cells using voltage-switching mode scanning electrochemical microscopy  

PubMed Central

We describe voltage-switching mode scanning electrochemical microscopy (VSM-SECM), in which a single SECM tip electrode was used to acquire high-quality topographical and electrochemical images of living cells simultaneously. This was achieved by switching the applied voltage so as to change the faradaic current from a hindered diffusion feedback signal (for distance control and topographical imaging) to the electrochemical flux measurement of interest. This imaging method is robust, and a single nanoscale SECM electrode, which is simple to produce, is used for both topography and activity measurements. In order to minimize the delay at voltage switching, we used pyrolytic carbon nanoelectrodes with 6.5–100 nm radii that rapidly reached a steady-state current, typically in less than 20 ms for the largest electrodes and faster for smaller electrodes. In addition, these carbon nanoelectrodes are suitable for convoluted cell topography imaging because the RG value (ratio of overall probe diameter to active electrode diameter) is typically in the range of 1.5–3.0. We first evaluated the resolution of constant-current mode topography imaging using carbon nanoelectrodes. Next, we performed VSM-SECM measurements to visualize membrane proteins on A431 cells and to detect neurotransmitters from a PC12 cells. We also combined VSM-SECM with surface confocal microscopy to allow simultaneous fluorescence and topographical imaging. VSM-SECM opens up new opportunities in nanoscale chemical mapping at interfaces, and should find wide application in the physical and biological sciences.

Takahashi, Yasufumi; Shevchuk, Andrew I.; Novak, Pavel; Babakinejad, Babak; Macpherson, Julie; Unwin, Patrick R.; Shiku, Hitoshi; Gorelik, Julia; Klenerman, David; Korchev, Yuri E.; Matsue, Tomokazu

2012-01-01

91

Topographical and electrochemical nanoscale imaging of living cells using voltage-switching mode scanning electrochemical microscopy.  

PubMed

We describe voltage-switching mode scanning electrochemical microscopy (VSM-SECM), in which a single SECM tip electrode was used to acquire high-quality topographical and electrochemical images of living cells simultaneously. This was achieved by switching the applied voltage so as to change the faradaic current from a hindered diffusion feedback signal (for distance control and topographical imaging) to the electrochemical flux measurement of interest. This imaging method is robust, and a single nanoscale SECM electrode, which is simple to produce, is used for both topography and activity measurements. In order to minimize the delay at voltage switching, we used pyrolytic carbon nanoelectrodes with 6.5-100 nm radii that rapidly reached a steady-state current, typically in less than 20 ms for the largest electrodes and faster for smaller electrodes. In addition, these carbon nanoelectrodes are suitable for convoluted cell topography imaging because the RG value (ratio of overall probe diameter to active electrode diameter) is typically in the range of 1.5-3.0. We first evaluated the resolution of constant-current mode topography imaging using carbon nanoelectrodes. Next, we performed VSM-SECM measurements to visualize membrane proteins on A431 cells and to detect neurotransmitters from a PC12 cells. We also combined VSM-SECM with surface confocal microscopy to allow simultaneous fluorescence and topographical imaging. VSM-SECM opens up new opportunities in nanoscale chemical mapping at interfaces, and should find wide application in the physical and biological sciences. PMID:22611191

Takahashi, Yasufumi; Shevchuk, Andrew I; Novak, Pavel; Babakinejad, Babak; Macpherson, Julie; Unwin, Patrick R; Shiku, Hitoshi; Gorelik, Julia; Klenerman, David; Korchev, Yuri E; Matsue, Tomokazu

2012-05-18

92

An Interactive Multimedia Software Program for Exploring Electrochemical Cells.  

ERIC Educational Resources Information Center

Describes computer-animated sequences and interactive multimedia instructional programs for use in introductory chemistry which allow students to explore electrochemical cells. The workbench section enables students to manipulate the experimental apparatus, chemicals, and instruments in order to design and build an experiment. The interactive…

Greenbowe, Thomas J.

1994-01-01

93

Oxide modified air electrode surface for high temperature electrochemical cells  

DOEpatents

An electrochemical cell is made having a porous cermet electrode (16) and a porous lanthanum manganite electrode (14), with solid oxide electrolyte (15) between them, where the lanthanum manganite surface next to the electrolyte contains a thin discontinuous layer of high surface area cerium oxide and/or praseodymium oxide, preferably as discrete particles (30) in contact with the air electrode and electrolyte.

Singh, Prabhakar (Export, PA); Ruka, Roswell J. (Churchill Boro, Allegheny County, PA)

1992-01-01

94

Electrode heat balances of electrochemical cells: Application to water electrolysis  

Microsoft Academic Search

Irreversible thermodynamics has been used to describe electrode heat balances of electrochemical cells. The specific example of electrolysis of water in molten sodium hydroxide is chosen for the purpose of illustration. Experimental data are presented for this system. The importance of a distinction between time and chargedependent changes in entropy is pointed out. Only changes of the last type contribute

Y. Ito; T. Forland; H. Kaiya; S. K. Ratkja; S. Yoshizawa

1984-01-01

95

Wet proofed conductive current collector for the electrochemical cells  

Microsoft Academic Search

In an electrochemical cell in which one of the electrodes is exposed to water, the combination comprising, (A) a housing, (B) a fluid impervious ion transporting membrane separating said housing into anode an cathode chamber, (C) a catalytic anode electrode bonded to the side of said membrane facing the anode chamber and adapter to the exposed to a fuel gas,

1980-01-01

96

Testing and analyses of electrochemical cells using frequency response  

Microsoft Academic Search

The feasibility of electrochemical impedance spectroscopy as a method for analyzing battery state of health and state of charge was investigated. Porous silver, zinc, nickel, and cadmium electrodes as well as silver\\/zinc cells were studied. State of charge could be correlated with impedance data for all but the nickel electrodes. State of health was correlated with impedance data for two

O. A. Norton Jr.; D. L. Thomas

1992-01-01

97

Secondary fuel cell. [electrolytically-regenerative hydrogen fuel cells  

Microsoft Academic Search

This application discloses a secondary fuel cell having improved electrode zones. Each cell has two electrode zones each containing a pair of electrode structures. A first such electrode structure in each zone is more efficient in operation during discharge of the fuel cell. Electrical structure is provided so that the first electrode structures are utilized during charging of the fuel

R. J. Haas; D. C. Briggs

1978-01-01

98

Method for making an electrochemical cell  

DOEpatents

Described is a thin-film battery, especially a thin-film microbattery, and a method for making the same, having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode. Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between {minus}15 C and 150 C. 9 figs.

Bates, J.B.; Dudney, N.J.

1996-10-22

99

Phase-flip transition in coupled electrochemical cells  

NASA Astrophysics Data System (ADS)

Time delay is introduced in the coupling between a pair of electrochemical cells. As coupling parameters are varied, the anodic current in the two cells oscillate in synchrony in regimes of periodic as well as chaotic dynamics. When the time delay is varied a phase-flip transition is observed: the relative phase between the synchronized oscillations changes abruptly by ? . This is accompanied by an experimentally measurable discontinuous change in the frequency of the synchronized oscillators.

Cruz, J. M.; Escalona, J.; Parmananda, P.; Karnatak, R.; Prasad, A.; Ramaswamy, R.

2010-04-01

100

Method of low temperature operation of an electrochemical cell array  

DOEpatents

A method is described for operating an electrochemical cell generator apparatus containing a generator chamber containing an array of cells having interior and exterior electrodes with solid electrolyte between the electrodes, where a hot gas contacts the outside of the cells and the generating chamber normally operates at over 850 C, where N[sub 2] gas is fed to contact the interior electrode of the cells in any case when the generating chamber temperature drops for whatever reason to within the range of from 550 C to 800 C, to eliminate cracking within the cells. 2 figures.

Singh, P.; Ruka, R.J.; Bratton, R.J.

1994-04-26

101

Photoelectrolysis of water in semiconductor septum electrochemical photovoltaic cells  

SciTech Connect

Producing hydrogen from water has been the dream of generations of energy-conscious scientists and engineers. That dream may at last be realized in the semiconductor septum electrochemical photovoltaic (SC-SEP) cell, which is modeled after nature's photosynthetic thylakoid membrane. The novel SC-SEP cell arose from studies of pigmented bilayer lipid membranes. The cell is easy to construct and simple to operate. It appears to offer a practical approach to the photochemical conversion and storage of solar energy. This report describes how hydrogen is produced from artificial sea water when an SC-SEP cell is irradiated by the visible light of the solar spectrum.

Tien, H.T.; Chen, J.W. (Michigan State Univ., East Lansing (United States))

1992-01-01

102

Electrochemical characterization of the bacterial cell surface  

Microsoft Academic Search

Bacterial cells are ubiquitous in natural environments and also play important roles in domestic and industrial processes. They are found either suspended in the aqueous phase or attached to solid particles. The adhesion behaviour of bacteria is influenced by the physico-chemical properties of their cell surfaces, such as hydrophobicity and cell wall charge. The charge in the bacterial wall originates

Wal van der A

1996-01-01

103

Electrochemical As(III) whole-cell based biochip sensor.  

PubMed

The development of a whole-cell based sensor for arsenite detection coupling biological engineering and electrochemical techniques is presented. This strategy takes advantage of the natural Escherichia coli resistance mechanism against toxic arsenic species, such as arsenite, which consists of the selective intracellular recognition of arsenite and its pumping out from the cell. A whole-cell based biosensor can be produced by coupling the intracellular recognition of arsenite to the generation of an electrochemical signal. Hereto, E. coli was equipped with a genetic circuit in which synthesis of beta-galactosidase is under control of the arsenite-derepressable arsR-promoter. The E. coli reporter strain was filled in a microchip containing 16 independent electrochemical cells (i.e. two-electrode cell), which was then employed for analysis of tap and groundwater samples. The developed arsenic-sensitive electrochemical biochip is easy to use and outperforms state-of-the-art bacterial bioreporters assays specifically in its simplicity and response time, while keeping a very good limit of detection in tap water, i.e. 0.8ppb. Additionally, a very good linear response in the ranges of concentration tested (0.94ppb to 3.75ppb, R(2)=0.9975 and 3.75 ppb to 30ppb, R(2)=0.9991) was obtained, complying perfectly with the acceptable arsenic concentration limits defined by the World Health Organization for drinking water samples (i.e. 10ppb). Therefore, the proposed assay provides a very good alternative for the portable quantification of As (III) in water as corroborated by the analysis of natural groundwater samples from Swiss mountains, which showed a very good agreement with the results obtained by atomic absorption spectroscopy. PMID:23584229

Cortés-Salazar, Fernando; Beggah, Siham; van der Meer, Jan Roelof; Girault, Hubert H

2013-03-20

104

A biofuel cell with electrochemically switchable and tunable power output.  

PubMed

An electroswitchable and tunable biofuel cell based on the biocatalyzed oxidation of glucose is described. The anode consists of a Cu(2+)-poly(acrylic acid) film on which the redox-relay pyrroloquinoline quinone (PQQ) and the flavin adenine dinucleotide (FAD) cofactor are covalently linked. Apo-glucose oxidase is reconstituted on the FAD sites to yield the glucose oxidase (GOx)-functionalized electrode. The cathode consists of a Cu(2+)-poly(acrylic acid) film that provides the functional interface for the covalent linkage of cytochrome c (Cyt c) that is further linked to cytochrome oxidase (COx). Electrochemical reduction of the Cu(2+)-poly(acrylic acid) films (applied potential -0.5 V vs SCE) associated with the anode and cathode yields the conductive Cu(0)-poly(acrylic acid) matrixes that electrically contact the GOx-electrode and the COx/Cyt c-electrode, respectively. The short-circuit current and open-circuit voltage of the biofuel cell correspond to 105 microA (current density ca. 550 microA cm(-2)) and 120 mV, respectively, and the maximum extracted power from the cell is 4.3 microW at an external loading resistance of 1 kOmega. The electrochemical oxidation of the polymer films associated with the electrodes (applied potential 0.5 V) yields the nonconductive Cu(2+)-poly(acrylic acid) films that completely block the biofuel cell operation. By the cyclic electrochemical reduction and oxidation of the polymer films associated with the anode and cathode between the Cu(0)-poly(acrylic acid) and Cu(2+)-poly(acrylic acid) states, the biofuel cell performance is reversibly switched between "ON" and "OFF" states, respectively. The electrochemical reduction of the Cu(2+)-polymer film to the Cu(0)-polymer film is a slow process (ca. 1000 s) because the formation and aggregation of the Cu(0)-clusters requires the migration of Cu(2+) ions in the polymer film and their reduction at conductive sites. The slow reduction of the Cu(2+)-polymer films allows for the controlling of the content of conductive domains in the films and the tuning of the output power of the biofuel cell. The electron-transfer resistances of the cathodic and anodic processes were characterized by impedance spectroscopy. Also, the overall resistances of the biofuel cell generated by the time-dependent electrochemical reduction process were followed by impedance spectroscopy and correlated with the internal resistances of the cell upon its operation. PMID:12769592

Katz, Eugenii; Willner, Itamar

2003-06-01

105

Electrochemical cell and separator plate thereof  

DOEpatents

A fuel cell includes a separator plate having first and second flow channels extending there through contiguously with an electrode and respectively in flow communication with the cell electrolyte and in flow isolation with respect to such electrolyte. In fuel cell system arrangement, the diverse type channels are supplied in common with process gas for thermal control purposes. The separator plate is readily formed by corrugation of integral sheet material. 10 figs.

Baker, B.S.; Dharia, D.J.

1979-10-02

106

Transient capacitance of light-emitting electrochemical cells  

NASA Astrophysics Data System (ADS)

We present time-dependent measurements of the capacitance, current, and optical emission of light-emitting electrochemical cells as a constant voltage bias is applied and removed. We find that the capacitance increases more rapidly than the light or current and can be oscillatory in time. The transient behavior suggests that the capacitance is determined by a combination of ion distribution, free carrier screening and junction width.

Davis, Y. A.; Crooker, P. P.; Haegel, N. M.; Yoshioka, Y.; MacKenzie, J. D.

2011-12-01

107

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

A high temperature, solid electrolyte electrochemical cell is made, having a first and second electrode with solid electrolyte between them, where the electrolyte is formed by hot chemical vapor deposition, where a solid, interlayer material, which is electrically conductive, oxygen permeable, and protective of electrode material from hot metal halide vapor attack, is placed between the first electrode and the electrolyte, to protect the first electrode from the hot metal halide vapors during vapor deposition.

Isenberg, Arnold O. (Forest Hills Boro, PA); Ruka, Roswell J. (Churchill Boro, PA)

1986-01-01

108

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

A high temperature, solid electrolyte electrochemical cell is made, having a first and second electrode with solid electrolyte between them, where the electrolyte is formed by hot chemical vapor deposition, where a solid, interlayer material, which is electrically conductive, oxygen permeable, and protective of electrode material from hot metal halide vapor attack, is placed between the first electrode and the electrolyte, to protect the first electrode from the hot metal halide vapors during vapor deposition.

Isenberg, Arnold O. (Forest Hills Boro, PA); Ruka, Roswell J. (Churchill Boro, PA); Zymboly, Gregory E. (Penn Hills Township, Allegheny County, PA)

1985-01-01

109

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

A high temperature, solid electrolyte electrochemical cell is made, having a first and second electrode with solid electrolyte between them, where the electrolyte is formed by hot chemical vapor deposition, where a solid, interlayer material, which is electrically conductive, oxygen permeable, and protective of electrode material from hot metal halide vapor attack, is placed between the first electrode and the electrolyte, to protect the first electrode from the hot metal halide vapors during vapor deposition.

Isenberg, Arnold O. (Forest Hills Boro, PA); Ruka, Roswell J. (Churchill Boro, PA)

1987-01-01

110

Electrochemical power-producing cell. [Li/Se  

DOEpatents

An electrochemical power-producing cell including a molten lithium metal anode, a molten selenium metal cathode, a paste electrolyte separating the anode from the cathode, an anode current collector, and a single layer of niobium expanded metal formed in corrugated shape as cathode current collector is described. In addition, means are provided for sealing the anode and the cathode from loss of lithium and selenium, respectively, and an insulator is provided between the anode housing and the paste electrolyte disk.

Cairns, E.J.; Chilenskas, A.A.; Steunenberg, R.K.; Shimotake, H.

1972-05-30

111

Separation of CO2 from flue gas using electrochemical cells  

SciTech Connect

ABSTRACT Past research with high temperature molten carbonate electrochemical cells has shown that carbon dioxide can be separated from flue gas streams produced by pulverized coal combustion for power generation, However, the presence of trace contaminants, i.e" sulfur dioxide and nitric oxides, will impact the electrolyte within the cell. If a lower temperature cell could be devised that would utilize the benefits of commercially-available, upstream desulfurization and denitrification in the power plant, then this CO2 separation technique can approach more viability in the carbon sequestration area, Recent work has led to the assembly and successful operation of a low temperature electrochemical cell. In the proof-of-concept testing with this cell, an anion exchange membrane was sandwiched between gas-diffusion electrodes consisting of nickel-based anode electrocatalysts on carbon paper. When a potential was applied across the cell and a mixture of oxygen and carbon dioxide was flowed over the wetted electrolyte on the cathode side, a stream of CO2 to O2 was produced on the anode side, suggesting that carbonate/ bicarbonate ions are the CO2 carrier in the membrane. Since a mixture of CO 2 and 02 is produced, the possibility exists to use this stream in oxy-firing of additional fuel. From this research, a novel concept for efficiently producing a carbon dioxide rich effiuent from combustion of a fossil fuel was proposed. Carbon dioxide and oxygen are captured from the flue gas of a fossilfuel combustor by one or more electrochemical cells or cell stacks. The separated stream is then transferred to an oxy-fired combustor which uses the gas stream for ancillary combustion, ultimately resulting in an effluent rich in carbon dioxide, A portion of the resulting flow produced by the oxy-fired combustor may be continuously recycled back into the oxy-fired combustor for temperature control and an optimal carbon dioxide rich effluent.

Pennline, H.W; Granite, E.J.; Luebke, D.R; Kitchin, J.R; Landon, J.; Weiland, L.M.

2010-06-01

112

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

The invention is comprised of an electrically conducting doped or admixed cerium oxide composition with niobium oxide and/or tantalum oxide for electrochemical devices, characterized by the general formula: Nb{sub x}Ta{sub y}Ce{sub 1{minus}x{minus}y}O{sub 2} where x is about 0.0 to 0.05, y is about 0.0 to 0.05, and x+y is about 0.02 to 0.05, and where x is preferably about 0.02 to 0.05 and y is 0, and a method of making the same is also described. This novel composition is particularly applicable in forming a protective interlayer of a high temperature, solid electrolyte electrochemical cell, characterized by a first electrode; an electrically conductive interlayer of niobium and/or tantalum doped cerium oxide deposited over at least a first portion of the first electrode; an interconnect deposited over the interlayer; a solid electrolyte deposited over a second portion of the first electrode, the first portion being discontinuous from the second portion; and, a second electrode deposited over the solid electrolyte. The interlayer is characterized as being porous and selected from the group consisting of niobium doped cerium oxide, tantalum doped cerium oxide, and niobium and tantalum doped cerium oxide or admixtures of the same. The first electrode, an air electrode, is a porous layer of doped lanthanum manganite, the solid electrolyte layer is a dense yttria stabilized zirconium oxide, the interconnect layer is a dense, doped lanthanum chromite, and the second electrode, a fuel electrode, is a porous layer of nickel-zirconium oxide cermet. The electrochemical cell can take on a plurality of shapes such as annular, planar, etc. and can be connected to a plurality of electrochemical cells in series and/or in parallel to generate electrical energy. 5 figs.

Singh, P.; Vasilow, T.R.; Richards, V.L.

1996-05-14

113

Protective interlayer for high temperature solid electrolyte electrochemical cells  

DOEpatents

The invention comprises of an electrically conducting doped or admixed cerium oxide composition with niobium oxide and/or tantalum oxide for electrochemical devices, characterized by the general formula: Nb.sub.x Ta.sub.y Ce.sub.1-x-y O.sub.2 where x is about 0.0 to 0.05, y is about 0.0 to 0.05, and x+y is about 0.02 to 0.05, and where x is preferably about 0.02 to 0.05 and y is 0, and a method of making the same. This novel composition is particularly applicable in forming a protective interlayer of a high temperature, solid electrolyte electrochemical cell (10), characterized by a first electrode (12); an electrically conductive interlayer (14) of niobium and/or tantalum doped cerium oxide deposited over at least a first portion (R) of the first electrode; an interconnect (16) deposited over the interlayer; a solid electrolyte (18) deposited over a second portion of the first electrode, the first portion being discontinuous from the second portion; and, a second electrode (20) deposited over the solid electrolyte. The interlayer (14) is characterized as being porous and selected from the group consisting of niobium doped cerium oxide, tantalum doped cerium oxide, and niobium and tantalum doped cerium oxide or admixtures of the same. The first electrode (12), an air electrode, is a porous layer of doped lanthanum manganite, the solid electrolyte layer (18) is a dense yttria stabilized zirconium oxide, the interconnect layer (16) is a dense, doped lanthanum chromite, and the second electrode (20), a fuel electrode, is a porous layer of nickel-zirconium oxide cermet. The electrochemical cell (10) can take on a plurality of shapes such as annular, planar, etc. and can be connected to a plurality of electrochemical cells in series and/or in parallel to generate electrical energy.

Singh, Prabhakar (Export, PA); Vasilow, Theodore R. (Manor, PA); Richards, Von L. (Angola, IN)

1996-01-01

114

Design and applications of an in situ electrochemical NMR cell  

NASA Astrophysics Data System (ADS)

A device using a three-electrode electrochemical cell (referred to as an ECNMR cell) was successfully constructed that could be used in a standard 5 mm NMR probe to acquire high-resolution NMR spectra while the working electrode was held at a constant electrical potential. The working electrode was a 20 nm thick gold film thermally coated on the outside of an inner 3 mm glass tube. An underlayer consisting of (3-mercaptopropyl)trimethoxy-silane was coated on the glass surface in order to improve its adhesion to gold. Tests showed prolonged life of the gold film. Details of the design and construction of the ECNMR cell are described. The ECNMR cell could be routinely used in a multi-user service high-resolution NMR instrument under oxygen-free conditions in both aqueous and non-aqueous solvents. Different approaches were applied to suppress the noise transmitted between the potentiostat and the NMR spectrometer. These approaches were shown to be effective in reducing background noise in the NMR spectra. The electrochemical and NMR performance of the ECNMR cell is presented. The reduction of 1,4-benzoquinone in both aqueous and non-aqueous solvents was used for testing. The evolution of the in situ ECNMR spectra with time demonstrated that use of the ECNMR cell was feasible. Studies of caffeic acid and 9-chloroanthracene using this ECNMR cell were undertaken to explore its applications, such as monitoring reactions and studying their reaction mechanisms.

Zhang, Xiaocan; Zwanziger, Josef W.

2011-01-01

115

Fuel Cells and Electrochemical Energy Storage.  

ERIC Educational Resources Information Center

|Discusses the nature of phosphoric acid, molten carbonate, and solid oxide fuel cells and major features and types of batteries used for electrical energy storage. Includes two tables presenting comparison of major battery features and summary of major material problems in the sodium-sulfur and lithium-alloy metal sulfide batteries. (JN)|

Sammells, Anthony F.

1983-01-01

116

Electrochemical cell with high discharge/charge rate capability  

DOEpatents

A fully charged positive electrode composition for an electrochemical cell includes FeS.sub.2 and NiS.sub.2 in about equal molar amounts along with about 2-20 mole percent of the reaction product Li.sub.2 S. Through selection of appropriate electrolyte compositions, high power output or low operating temperatures can be obtained. The cell includes a substantially constant electrode impedance through most of its charge and discharge range. Exceptionally high discharge rates and overcharge protection are obtainable through use of the inventive electrode composition.

Redey, Laszlo (Downers Grove, IL)

1988-01-01

117

Electrochemical cell and process for manufacturing temperature sensitive solutions  

SciTech Connect

An electrochemical cell for regenerating temperature sensitive solutions is described. In a preferred construction, the cell comprises a central electrode chamber and two counterelectrode chambers. To maintain the temperature of the electrolyte within a desired temperature range, the electrode in the electrode chamber is formed from at least one hollow tube through which a heat exchange medium flows. In a preferred construction, the electrode comprises a plurality of hollow tubes and a plurality of current collectors bonded to the tubes to form a grid-like structure.

Kadija, I.V.

1984-11-13

118

Composite bipolar plate for electrochemical cells  

DOEpatents

A bipolar separator plate for fuel cells consists of a molded mixture of a vinyl ester resin and graphite powder. The plate serves as a current collector and may contain fluid flow fields for the distribution of reactant gases. The material is inexpensive, electrically conductive, lightweight, strong, corrosion resistant, easily mass produced, and relatively impermeable to hydrogen gas. The addition of certain fiber reinforcements and other additives can improve the properties of the composite material without significantly increasing its overall cost.

Wilson, Mahlon S. (Los Alamos, NM); Busick, Deanna N. (Los Alamos, NM)

2001-01-01

119

ECC (Electrochemical Concentration Cell) Ozonesonde Observations at Mirny, Antarctica, during 1988.  

National Technical Information Service (NTIS)

Atmospheric ozone vertical distributions, air temperatures, and wind speed and direction data are presented for 40 balloon electrochemical concentration cell ozone soundings made at Mirny, Antarctica, in 1988.

W. D. Komhyr J. A. Lathrop V. N. Arbuzova V. U. Khattatov P. G. Nureyev

1989-01-01

120

Microfabricated Microbial Fuel Cell Arrays Reveal Electrochemically Active Microbes  

PubMed Central

Microbial fuel cells (MFCs) are remarkable “green energy” devices that exploit microbes to generate electricity from organic compounds. MFC devices currently being used and studied do not generate sufficient power to support widespread and cost-effective applications. Hence, research has focused on strategies to enhance the power output of the MFC devices, including exploring more electrochemically active microbes to expand the few already known electricigen families. However, most of the MFC devices are not compatible with high throughput screening for finding microbes with higher electricity generation capabilities. Here, we describe the development of a microfabricated MFC array, a compact and user-friendly platform for the identification and characterization of electrochemically active microbes. The MFC array consists of 24 integrated anode and cathode chambers, which function as 24 independent miniature MFCs and support direct and parallel comparisons of microbial electrochemical activities. The electricity generation profiles of spatially distinct MFC chambers on the array loaded with Shewanella oneidensis MR-1 differed by less than 8%. A screen of environmental microbes using the array identified an isolate that was related to Shewanella putrefaciens IR-1 and Shewanella sp. MR-7, and displayed 2.3-fold higher power output than the S. oneidensis MR-1 reference strain. Therefore, the utility of the MFC array was demonstrated.

Cho, Younghak; de Figueiredo, Paul; Han, Arum

2009-01-01

121

Silver composite cathodes for alkaline secondary batteries  

Microsoft Academic Search

This invention relates to electrochemical cells and more particularly to silver electrodes for electrochemical cells. Accordingly, an object of this invention is to provide a new, lighter weight silver electrode for secondary cells. Another object of this invention is to provide an electrode which requires less silver to operate. A further object of this invention is to provide a silver

William A. Ferrando

1989-01-01

122

A graphene functionalized electrochemical aptasensor for selective label-free detection of cancer cells  

Microsoft Academic Search

Here we report an electrochemical sensor that can realize label-free cancer cell detection using the first clinical trial II used aptamer AS1411 and functionalized graphene. By taking advantages of AS1411 high binding affinity and specificity to the overexpressed nucleolin on the cancer cell surface, our developed electrochemical aptasensor can distinguish cancer cells and normal ones and detect as low as

Lingyan Feng; Yong Chen; Jinsong Ren; Xiaogang Qu

2011-01-01

123

Electrochemical cell for obtaining oxygen from carbon dioxide atmospheres  

SciTech Connect

To support human life on the Martian surface, an electrochemical device will be required to obtain oxygen from the carbon dioxide rich atmosphere. The electrolyte employed in such a device must be constructed from extremely thin, dense membranes to efficiently acquire the oxygen necessary to support life. A forming process used industrially in the production of multilayer capacitors and electronic substrates was adapted to form the thin membranes required. The process, known as the tape casting, involves the suspension consisting of solvents and binders. The suspension is passed under a blade, resulting in the production of ceramic membranes between 0.1 and 0.5 mm thick. Once fired, the stabilized zirconia membranes were assembled into the cell design by employing a zirconium phosphate solution as the sealing agent. The resulting ceramic-to-ceramic seals were found to be structurally sound and gas-tight. Furthermore, by using a zirconia-based solution to assemble the cell, the problem of a thermal expansion mismatch was alleviated. By adopting an industrial forming process to produce thin membranes, an electrochemical cell for obtaining oxygen from carbon dioxide was produced. The proposed cell design is unique in that it does not require a complicated manifold system for separating the various gases present in this process, nor does it require a series of complex electrical connections. Thus, the device can reliably obtain the vital oxygen supply from the toxic carbon dioxide atmosphere.

Hooker, M.; Rast, H.E.; Rogers, D.K.; Borja, L.; Clark, K.; Fleming, K.; Mcgurren, M.; Oldaker, T.; Sweet, N.

1989-07-01

124

Electrochemical impedance spectra of solid-oxide fuel cells and polymer membrane fuel cells  

Microsoft Academic Search

Electrochemical impedance spectroscopy (EIS) is a very useful method for the characterization of fuel cells. The anode and cathode transfer functions have been determined independently without a reference electrode using symmetric gas supply of hydrogen or oxygen on both electrodes of the fuel cell at open circuit potential (OCP). EIS are given for both polymer electrolyte fuel cells (PEFC) and

N. Wagner; W. Schnurnberger; B. Müller; M. Lang

1998-01-01

125

Method of electrode fabrication for solid oxide electrochemical cells  

DOEpatents

A process for fabricating cermet electrodes for solid oxide electrochemical cells by sintering is disclosed. First, a porous metal electrode is fabricated on a solid oxide cell, such as a fuel cell by, for example, sintering, and is then infiltrated with a high volume fraction stabilized zirconia suspension. A second sintering step is used to sinter the infiltrated zirconia to a high density in order to more securely attach the electrode to the solid oxide electrolyte of the cell. High performance fuel electrodes can be obtained with this process. Further electrode performance enhancement may be achieved if stabilized zirconia doped with cerium oxide, chromium oxide, titanium oxide, and/or praseodymium oxide for electronic conduction is used. 5 figs.

Jensen, R.R.

1990-11-20

126

Method of electrode fabrication for solid oxide electrochemical cells  

DOEpatents

A process for fabricating cermet electrodes for solid oxide electrochemical cells by sintering is disclosed. First, a porous metal electrode is fabricated on a solid oxide cell, such as a fuel cell by, for example, sintering, and is then infiltrated with a high volume fraction stabilized zirconia suspension. A second sintering step is used to sinter the infiltrated zirconia to a high density in order to more securely attach the electrode to the solid oxide electrolyte of the cell. High performance fuel electrodes can be obtained with this process. Further electrode performance enhancement may be achieved if stabilized zirconia doped with cerium oxide, chromium oxide, titanium oxide, and/or praseodymium oxide for electronic conduction is used.

Jensen, Russell R. (Murrysville, PA)

1990-01-01

127

Electrochemical behaviour of SnO 2 doped with boron and indium in anodes for lithium secondary batteries  

Microsoft Academic Search

Nanoparticles of SnO2 were doped with boron and indium for use as active anode materials in non-aqueous lithium batteries. The cells thus obtained were found to exhibit between 1.0 and 0.0 V their best cycling properties. Undoped SnO2 and particularly low boron-doped samples exhibited the best electrochemical characteristics, as reflected in an increased specific capacity and in improved cycling properties.

Julián Morales; Luis Sánchez

1999-01-01

128

Electrodes for Electrochemical Supercapacitors  

Microsoft Academic Search

Manganese dioxide nanoparticles were prepared by a chemical precipitation method. Composite electrodes for electrochemical supercapacitors (ES) were fabricated by impregnation of slurries of the manganese dioxide nanoparticles and carbon black into porous nickel foam current collectors. In the composite electrodes, carbon black nanoparticles formed a secondary conductivity network within the nickel foam cells. Obtained composite electrodes, containing manganese dioxide and

Gideon Moses Jacob; Quan Min Yang; Igor Zhitomirsky

2009-01-01

129

Fully transparent, organic light-emitting electrochemical cells  

NASA Astrophysics Data System (ADS)

We report the fabrication and performance of fully transparent, organic blue light-emitting electrochemical cells (OLECs), in which both the anode and cathode are made of indium tin oxide. The active layer is a blend of polyfluorene with long and flexible alkyl side chains grafted on the 9,9 position and of a molten salt. Two identical spin-coated active layers are laminated together at high temperature to form the OLECs. The electroluminescence threshold is around 3.3 V and the light intensity exceeds 10 muW/cm2 at 5 V.

Ouisse, T.; Armand, M.; Kervella, Y.; Stephan, O.

2002-10-01

130

Lithium electrochemical cell containing diethylcarbonate as an electrolyte solvent additive  

SciTech Connect

The general object of this invention is to provide an improved lithium electrochemical cell, including lithium and cobalt oxide as the cathode active material. Other light metals or composites may be applicable as the anode such as sodium, potassium and aluminum, or any conductively doped polymeric material or similar compound. Moreover, the positive electrode or cathode may be any oxide, sulfide or combinations of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, hafnium, tantalum, or tungsten or any conductively doped polymeric material or similar compound.

Plichta, E.J.; Slane, S.M.

1988-07-01

131

In vitro electrochemical corrosion and cell viability studies on nickel-free stainless steel orthopedic implants.  

PubMed

The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen's structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments. PMID:23630603

Salahinejad, Erfan; Hadianfard, Mohammad Jafar; Macdonald, Digby Donald; Sharifi-Asl, Samin; Mozafari, Masoud; Walker, Kenneth J; Rad, Armin Tahmasbi; Madihally, Sundararajan V; Tayebi, Lobat

2013-04-22

132

Battery paste compositions and electrochemical cells for use therewith  

DOEpatents

An improved battery paste composition and a lead-acid electrochemical cell which incorporates the composition. The cell includes a positive current collector and a negative current collector which are each coated with a paste containing one or more lead-containing compositions and a paste vehicle to form a positive plate and a negative plate. An absorbent electrolyte-containing separator member may also be positioned between the positive and negative plates. The paste on the positive current collector, the negative current collector, or both further includes a special additive consisting of polyvinylsulfonic acid or salts thereof which provides many benefits including improved battery cycle life, increased charge capacity, and enhanced overall stability. The additive also makes the pastes smoother and more adhesive, thereby improving the paste application process. The paste compositions of interest may be used in conventional flat-plate cells or in spirally wound batteries with equal effectiveness.

Olson, John B. (Boulder, CO)

1999-12-07

133

Cycloaliphatic epoxide-based photocured gelled electrolytes for secondary lithium battery applications. Electrochemical kinetic studies  

Microsoft Academic Search

Cycloaliphatic epoxide-based thin gelled films prepared by ultraviolet photocuring were characterized electrochemically. Mixtures of ethylene carbonate and various organic liquids in different volume ratios were used as solvents. General composition of the electrolyte was cycloaliphatic epoxide (being sold under the trade name ENVIBAR by Union Carbide) 10 to 28 weight percent (w\\/o), polyethylene oxide (200,000 Mw) 4 to 10 w\\/o,

G. Nagasubramanian; S. Surampudi; G. Halpert

1994-01-01

134

Feasibility of hydrogen production in a steam-carbon electrochemical cell  

Microsoft Academic Search

A high temperature electrochemical cell with a bed of solid carbon at the anode and steam at the cathode is proposed for carbon-assisted hydrogen production. This scheme eliminates the uphill potential barrier and provides a significant reduction in the required electrical work input to produce hydrogen from steam. The electrochemical cell is made of an yttria stabilized zirconia electrolyte with

Andrew C. Lee; Reginald E. Mitchell; Turgut M. Gür

2011-01-01

135

Plant cell cultures: Chemical factories of secondary metabolites  

Microsoft Academic Search

This review deals with the production of high-value secondary metabolites including pharmaceuticals and food additives through plant cell cultures, shoot cultures, root cultures and transgenic roots obtained through biotechnological means. Plant cell and transgenic hairy root cultures are promising potential alternative sources for the production of high-value secondary metabolites of industrial importance. Recent developments in transgenic research have opened up

S Ramachandra Rao; G. A Ravishankar

2002-01-01

136

Electrochemical impedance spectroscopy of lithium-titanium disulfide rechargeable cells  

SciTech Connect

The two-terminal alternating current impedance of lithium-titanium disulfide (Li/TiS[sub 2]) rechargeable cells has been studies as a function of frequency, state-of-charge, and extended cycling. Analysis based on a plausible equivalent circuit model for the Li/TiS[sub 2] cell leads to evaluation of kinetic parameters for the various physicochemical processes occurring at the electrode/electrolyte interfaces. To investigate the causes of cell degradation during extended cycling, the parameters evaluated for cells cycled five times have been compared with the parameters of cells that have been cycled over 600 times. The findings are that the combined ohmic resistance of the electrolyte and electrodes suffers a ten-fold increase after extended cycling, while the charge-transfer resistance and diffusional impedance at the TiS[sub 2]/electrolyte interface are not significantly affected. The results reflect the morphological change and increase in area of the anode due to cycling. The study also shows that overdischarge of a cathode-limited cell causes a decrease in the diffusion coefficient of the lithium ion in the cathode. The study demonstrate the value of electrochemical impedance spectroscopy in investigating failure mechanisms. The approach and methodology followed here can be extended to other rechargeable lithium battery system.

Narayanan, S.R.; Shen, D.H.; Surampudi, S.; Attia, A.I.; Halpert, G. (California Inst. of Technology, Pasadena, CA (United States). Jet Propulsion Lab.)

1993-07-01

137

Electrochemically switchable platform for the micro-patterning and release of heterotypic cell sheets.  

PubMed

This article describes a dynamic platform in which the biointerfacial properties of micro-patterned domains can be switched electrochemically through the spatio-temporally controlled dissolution and adsorption of polyelectrolyte coatings. Insulating SU-8 micro-patterns created on a transparent indium tin oxide electrode by photolithography allowed for the local control over the electrochemical dissolution of polyelectrolyte mono- and multilayers, with polyelectrolytes shielded from the electrochemical treatment by the underlying photoresist stencil. The platform allowed for the creation of micro-patterned cell co-cultures through the electrochemical removal of a non-fouling polyelectrolyte coating and the localized adsorption of a cell adhesive one after attachment of the first cell population. In addition, the use of weak adhesive polyelectrolyte coatings on the photoresist domains allowed for the detachment of a contiguous heterotypic cell sheet upon electrochemical trigger. Cells grown on the ITO domains peeled off upon electrochemical dissolution of the sacrificial polyelectrolyte substrate, whereas adjacent cell areas on the insulated weakly adhesive substrate easily detached through the contractile force generated by neighboring cells. This electrochemical strategy for the micro-patterning and detachment of heterotypic cell sheets combines simplicity, precision and versatility, and presents great prospects for the creation of cellular constructs which mimic the cellular complexity of native tissues. PMID:21057978

Guillaume-Gentil, Orane; Gabi, Michael; Zenobi-Wong, Marcy; Vörös, Janos

2011-02-01

138

Fabrication of solid oxide fuel cell by electrochemical vapor deposition  

DOEpatents

In a high temperature solid oxide fuel cell (SOFC), the deposition of an impervious high density thin layer of electrically conductive interconnector material, such as magnesium doped lanthanum chromite, and of an electrolyte material, such as yttria stabilized zirconia, onto a porous support/air electrode substrate surface is carried out at high temperatures (/approximately/1100/degree/ /minus/ 1300/degree/C) by a process of electrochemical vapor deposition. In this process, the mixed chlorides of the specific metals involved react in the gaseous state with water vapor resulting in the deposit of an impervious thin oxide layer on the support tube/air electrode substrate of between 20--50 microns in thickness. An internal heater, such as a heat pipe, is placed within the support tube/air electrode substrate and induces a uniform temperature profile therein so as to afford precise and uniform oxide deposition kinetics in an arrangement which is particularly adapted for large scale, commercial fabrication of SOFCs.

Riley, B.; Szreders, B.E.

1988-04-26

139

Fabrication of solid oxide fuel cell by electrochemical vapor deposition  

DOEpatents

In a high temperature solid oxide fuel cell (SOFC), the deposition of an impervious high density thin layer of electrically conductive interconnector material, such as magnesium doped lanthanum chromite, and of an electrolyte material, such as yttria stabilized zirconia, onto a porous support/air electrode substrate surface is carried out at high temperatures (approximately 1100.degree.-1300.degree. C.) by a process of electrochemical vapor deposition. In this process, the mixed chlorides of the specific metals involved react in the gaseous state with water vapor resulting in the deposit of an impervious thin oxide layer on the support tube/air electrode substrate of between 20-50 microns in thickness. An internal heater, such as a heat pipe, is placed within the support tube/air electrode substrate and induces a uniform temperature profile therein so as to afford precise and uniform oxide deposition kinetics in an arrangement which is particularly adapted for large scale, commercial fabrication of SOFCs.

Brian, Riley (Willimantic, CT); Szreders, Bernard E. (Oakdale, CT)

1989-01-01

140

Electrochemical photovoltaic cells 2-6 compound thin film electrodes  

NASA Astrophysics Data System (ADS)

The program focused on developing stable, thin film II-VI compound electrodes with sunlight efficiencies of 10%, for use with aqueous polysulfide electrolyte in frontwall and backwall illuminated electrochemical photovoltaic cells. The main effort was directed towards establishing the relationships among processing of the thin films, resultant electronic properties, and I-V performance in order to produce electrodes with maximum power conversion efficiency. The efficiency of n-CdSe electrodes deposited on titanium substrates was improved from between 3 to 5% to 5.5% to 6.5% by refinement of the thin film processing parameters as well as electrode surface treatment with ZnCl2 solution. The efficiency of n-CdSe electrodes deposited on tin oxide coated glass improved was from between 3 to 4% to the range of 6 to 6.5% due to modifications of the electrode geometry dictated by a photon loss minimization, and to electrode etching treatment.

Russak, M. A.; Reichman, J.; Decarlo, J.; Creter, C.

1981-07-01

141

Transient Capacitance of Light-Emitting Electrochemical Cells  

NASA Astrophysics Data System (ADS)

Although the steady-state behavior of light-emitting electrochemical cells (LECs) has been addressed theoretically, the transient properties of LECs have yet to be studied in detail. We present time- and frequency-dependent measurements of the capacitance, current, and optical emission of LECs as a constant voltage bias is applied and removed. We find that the capacitance increases more rapidly than the light or current and, unlike the light and current behavior, can be oscillatory and even negative at lower frequencies. Variable temperature experiments were performed to enable observation of a range of transient phenomena that cannot be fully explored at room temperature. The transient behavior suggests that the capacitance is determined by a combination of ion distribution, free carrier screening, and junction width. We interpret our data by qualitatively extending the ideas of existing steady-state theory.

Haegel, Nancy; Davis, Yevtte; Crooker, Peter; MacKenzie, J. Devin; Yoshioka, Yuka

2012-02-01

142

Understanding the operation of light-emitting electrochemical cells  

NASA Astrophysics Data System (ADS)

The ionic concentration (cion) is demonstrated to play a critical role for the operation of wide-gap light-emitting electrochemical cells. p-type and n-type doped regions are observed to grow from the anode and cathode, respectively, and form a light-emitting p-n junction when cion>=0.1 ions/conjugated-polymer repeat unit. For lower cion, the doped regions come to a full stop before making contact and forming a p-n junction due to an ion-depletion effect. Finally, the n-type doped polymer is observed to be unstable over time under inert conditions, suggesting that a chemical side reaction between the n-type doped polymer and the electrolyte takes place.

Fang, Junfeng; Yang, Yali; Edman, Ludvig

2008-08-01

143

Encapsulating light-emitting electrochemical cells for improved performance  

NASA Astrophysics Data System (ADS)

We present a functional and scalable encapsulation of light-emitting electrochemical cells (LECs), which results in a measured ambient operation of >400 h at a brightness of >300 cd/m2 with a maximum efficacy of 6 lm/W, and a linearly extrapolated ambient operation of ~5600 h at >100 cd/m2. Our findings suggest that previous studies have underestimated the practical stability of appropriately encapsulated LECs. We also report that the dominant ambient degradation for non-encapsulated LECs is water-induced delamination of the cathode from the active layer, while encapsulated LECs in contrast are found to decay from spatial variations in the active layer composition.

Asadpoordarvish, Amir; Sandström, Andreas; Tang, Shi; Granström, Jimmy; Edman, Ludvig

2012-05-01

144

Interfacial phenomena observed in electrochemical systems (lithium-ion batteries, fuel cells, dye sensitized solar cells); causes, relevance and enhancements  

Microsoft Academic Search

This dissertation is aimed to understand the interfacial phenomena in electrochemical systems. Three electrochemical systems, namely, Lithium Ion Batteries, Fuel Cells and Dye Sensitized Solar Cells were chosen to elucidate the different type of the interfaces involved. In Lithium ion batteries the interface between an electrode and an electrolyte called as the solid electrolyte interface plays an important role in

Shabab Amiruddin

2008-01-01

145

Selective analysis of secondary amino acids in gelatin using pulsed electrochemical detection.  

PubMed

A method was developed for selective analysis of the secondary amino acids proline and 4-hydroxyproline from gelatin hydrolysates using anion-exchange high-performance liquid chromatography followed by integrated pulsed amperometric detection (HPLC-IPAD). An extraction scheme was implemented prior to HPLC-IPAD analysis to isolate the secondary amino acids by the removal of primary amino acids through derivatization with o-phthalaldehyde followed by solid-phase extraction with C18 packed columns. The use of the IPAD technique eliminated the need for a second derivatization step to detect secondary amino acids. The removal of interfering primary amino acids prior to chromatographic analysis allowed the use of isocratic mobile-phase conditions to achieve effective and efficient separation of the amino acids. This led to a more precise and accurate quantitation of their content in gelatin hydrolysates. Detection limits approach 10 parts per billion ( approximately 2 pmol/injection) with a chromatographic analysis time under 8 min. The ratios of secondary amino acids, in addition to their abundances, were used to distinguish gelatin manufactured from bovine, porcine, and fish raw material sources. PMID:17683165

Russell, Jason D; Dolphin, John M; Koppang, Miles D

2007-08-08

146

Non-faradaic electrochemical modification of catalytic activity in solid electrolyte cells  

Microsoft Academic Search

The catalytic activity and selectivity of metal catalysts used as electrodes in high temperature solid electrolyte cells can be altered dramatically and in a reversible manner. This is accomplished by electrochemically supplying oxygen anions onto catalytic surfaces via polarized metal-solid electrolyte interfaces. Oxygen anions, forced electrochemically to adsorb on the metal catalyst surface, alter the catalyst work function in a

C. G. Vayenas; S. Bebelis; S. Neophytides; I. V. Yentekakis

1989-01-01

147

TiO{sub 2}-Ti semiconductor septum based electrochemical photovoltaic cell  

SciTech Connect

The authors describe work of a semiconductor-septum electrochemical solar cell (SC-SEP, PEC). The cell studied has a TiO{sub 2}-Ti septum electrode which separates the two sections of the cell. Different redox couples were tested in the cell. The paper describes the steps in fabrication of the cell, and photoelectrochemical behaviour of the cell.

Kondapaneni, S.C.; Singh, D.; Srivastava, O.N. [Banaras Hindu Univ., Varanasi (India)

1992-10-01

148

Photosynthetic electrochemical cell charging infrastructure versus photovoltaic cell charging infrastructure for future electric vehicles  

Microsoft Academic Search

The automotive industry is migrating towards all- electric and plug-in hybrid electric vehicles. Nevertheless conventional energy, in the form of thermal power and nuclear power, are used to power these vehicles which are not green and clean. The photosynthetic electrochemical cell (PEC) is one of the alternative energy resources for EVs and PHEVs. It could prove to be the ideal

Arvind Vyas Ramanan; Muthukumaran Pakirisamy; Sheldon S. Williamson

2011-01-01

149

Method for transferring thermal energy and electrical current in thin-film electrochemical cells  

DOEpatents

An improved electrochemical generator is disclosed. The electrochemical generator includes a thin-film electrochemical cell which is maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of the cell, conducts current into and out of the cell and also conducts thermal energy between the cell and thermally conductive, electrically resistive material disposed on a vessel wall adjacent the conductor. The thermally conductive, electrically resistive material may include an anodized coating or a thin sheet of a plastic, mineral-based material or conductive polymer material. The thermal conductor is fabricated to include a resilient portion which expands and contracts to maintain mechanical contact between the cell and the thermally conductive material in the presence of relative movement between the cell and the wall structure. The electrochemical generator may be disposed in a hermetically sealed housing.

Rouillard, Roger (Beloeil, CA); Domroese, Michael K. (South St. Paul, MN); Hoffman, Joseph A. (Minneapolis, MN); Lindeman, David D. (Hudson, WI); Noel, Joseph-Robert-Gaetan (St-Hubert, CA); Radewald, Vern E. (Austin, TX); Ranger, Michel (Lachine, CA); Sudano, Anthony (Laval, CA); Trice, Jennifer L. (Eagan, MN); Turgeon, Thomas A. (Fridley, MN)

2003-05-27

150

Nanopillar based electrochemical biosensor for monitoring microfluidic based cell culture  

NASA Astrophysics Data System (ADS)

In-vitro assays using cultured cells have been widely performed for studying many aspects of cell biology and cell physiology. These assays also form the basis of cell based sensing. Presently, analysis procedures on cell cultures are done using techniques that are not integrated with the cell culture system. This approach makes continuous and real-time in-vitro measurements difficult. It is well known that the availability of continuous online measurements for extended periods of time will help provide a better understanding and will give better insight into cell physiological events. With this motivation we developed a highly sensitive, selective and stable microfluidic electrochemical glucose biosensor to make continuous glucose measurements in cell culture media. The performance of the microfluidic biosensor was enhanced by adding 3D nanopillars to the electrode surfaces. The microfluidic glucose biosensor consisted of three electrodes---Enzyme electrode, Working electrode, and Counter electrode. All these electrodes were enhanced with nanopillars and were optimized in their respective own ways to obtain an effective and stable biosensing device in cell culture media. For example, the 'Enzyme electrode' was optimized for enzyme immobilization via either a polypyrrole-based or a self-assembled-monolayer-based immobilization method, and the 'Working electrode' was modified with Prussian Blue or electropolymerized Neutral Red to reduce the working potential and also the interference from other interacting electro-active species. The complete microfluidic biosensor was tested for its ability to monitor glucose concentration changes in cell culture media. The significance of this work is multifold. First, the developed device may find applications in continuous and real-time measurements of glucose concentrations in in-vitro cell cultures. Second, the development of a microfluidic biosensor will bring technical know-how toward constructing continuous glucose monitoring devices. Third, the methods used to develop 3D electrodes incorporated with nanopillars can be used for other applications such as neural probes, fuel cells, solar cells etc., and finally, the knowledge obtained from the immobilization of enzymes onto nanostructures sheds some new insight into nanomaterial/biomolecule interactions.

Gangadharan, Rajan

151

Improved silver\\/zinc secondary cells for underwater applications  

Microsoft Academic Search

Performance improvements in silver\\/zinc technology have been achieved with new developments in additives and separator coatings. These improvements, aimed at increasing the cycle life and energy density of silver\\/zinc cells, were realized through advances in the stateof the-art of the zinc electrode and of the separators, which are the major limitations to this electrochemical couple. To achieve these objectives, two

James Skelton; Roberto Serenyi

1997-01-01

152

Transport in fuel cells: Electrochemical impedance spectroscopy and neutron imaging studies  

Microsoft Academic Search

This dissertation focuses on two powerful methods of performing in-situ studies of transport limitations in fuel cells. The first is electrochemical impedance spectroscopy (EIS) while the second is neutron imaging. Three fuel cell systems are studied in this work: polymer electrolyte membrane fuel cells (PEMFCs), microbial fuel cells (MFCs) and enzyme fuel cells (EFCs). The first experimental section of this

Douglas Scott Aaron

2010-01-01

153

Solid electrolyte-electrode system for an electrochemical cell  

DOEpatents

An electrochemical device including a solid electrolyte and solid electrode composed of materials having different chemical compositions and characterized by different electrical properties but having the same crystalline phase is provided. A method for fabricating an electrochemical device having a solid electrode and solid electrolyte characterized by the same crystalline phase is also provided.

Tuller, Harry L. (Wellesley, MA); Kramer, Steve A. (Somerville, MA); Spears, Marlene A. (Woburn, MA)

1995-01-01

154

Evaluation Program for Secondary Spacecraft Cells.  

National Technical Information Service (NTIS)

The evaluation program gathers statistical information concerning cell performance characteristics and limitations which is used by spacecraft power systems planners, designers, and integration teams. Weaknesses discovered in cell design are reported and ...

D. E. Christy J. D. Harkness

1974-01-01

155

Air electrode material for high temperature electrochemical cells  

DOEpatents

Disclosed is a solid solution with a perovskite-like crystal structure having the general formula La.sub.1-x-w (M.sub.L).sub.x (Ce).sub.w (M.sub.S1).sub.1-y (M.sub.S2).sub.y O.sub.3 where M.sub.L is Ca, Sr, Ba, or mixtures thereof, M.sub.S1 is Mn, Cr, or mixtures thereof and M.sub.S2 is Ni, Fe, Co, Ti, Al, In, Sn, Mg, Y, Nb, Ta, or mixtures thereof, w is about 0.05 to about 0.25, x+w is about 0.1 to about 0.7, and y is 0 to about 0.5. In the formula, M.sub.L is preferably Ca, w is preferably 0.1 to 0.2, x+w is preferably 0.4 to 0.7, and y is preferably 0. The solid solution can be used in an electrochemical cell where it more closely matches the thermal expansion characteristics of the support tube and electrolyte of the cell.

Ruka, Roswell J. (Churchill Boro, PA)

1985-01-01

156

Electrochemical characteristics of acid electrolytes for fuel cells  

NASA Astrophysics Data System (ADS)

The electrochemical evaluation of new perfluorinated fuel cell electrolytes provided by GRI contractors at Clemson and Iowa shows the kinetics for O2 reduction on Pt improves with these acids compared to with phosphoric acid. The improvement is mainly due to the lesser tendency of these acids to absorb on Pt. Kinetics do not have a strong dependence on pH or O2 solubility when mass transport is not involved. Concentrated sulfonyl acids were usually found to wet Teflon resulting in the flooding of Teflon-bonded gas fed electrodes and poor performance at high current densities. These perfluorinated electrolytes were, however, found to be useful as performance enhancing additives to concentrated phosphoric acid in some cases. The alpha, omega-bis-phosphonic acid with a perfluoroethylene bridge gave superior performance compared to phosphoric acid at elevated temperatures (up to 200 C) for 500 hours. Bis-phosphonic acids with higher CF2 to PO3H2 ratios dehydrated more readily at elevated temperatures, resulting in resistive voltage losses. New perfluorinated phosphonic acid containing olefins were found to be polymerizable. This suggests that with a reasonable synthetic effort, new kinds of ionomer membrames are attainable, and these may be superior to Nafion for fuel cell applications.

Gervasio, D.; Razaq, M.; Razaq, A.; Adzic, R.; Kanamura, K.; Yeager, E. B.

1992-01-01

157

Conversion and Storage in Electrochemical Photovoltaic Cells. Final Report, 15 September 1979-15 January 1985.  

National Technical Information Service (NTIS)

This research was undertaken to provide a better understanding of the parameters that must be controlled to make efficient electrochemical photovoltaic solar cells with inexpensive in situ energy storage. It has been demonstrated that reproducible, ''stab...

M. Tomkiewicz I. Ling W. S. Parson R. B. Silberstein J. K. Lyden

1985-01-01

158

Electrochemical in-situ reaction cell for X-ray scattering, diffraction and spectroscopy  

SciTech Connect

An electrochemical in-situ reaction cell for hard X-ray experiments with battery electrodes is described. Applications include the small angle scattering, diffraction, and near-edge spectroscopy of lithium manganese oxide electrodes.

Braun, Artur; Granlund, Eric; Cairns, Elton J.

2003-01-27

159

Phthalocyanine cathode materials for secondary lithium cells  

SciTech Connect

Discharge and charge characteristics of various phthalocyanine cathodes coupled with lithium metal are studied. The best capacity based only on cathode active material weight is 1440 A-hr/kg in the lithium/iron phthalocyanine system, and the cycle life of the lithium/Cu phthalocyanine system is more than 100 times at the discharge depth of 157 A-hr/kg. The cathode reaction mechanism is supposed to be lithium intercalation between phthalocyanine molecules. The results indicate that these phthalocyanines are promising cathode active materials for lithium secondary batteries. 15 refs.

Yamaki, J.; Yamaji, A.

1982-01-01

160

Phthalocyanine cathode materials for secondary lithium cells  

SciTech Connect

Discharge and charge characteristics of various phthalocyanine cathodes coupled with lithium metal are studied. The best capacity based only on cathode active material weight is 1440 A-hr/kg in the lithium/iron phthalocyanine system, and the cycle life of the lithium/Cu phthalocyanine system is more than 100 times at the discharge depth of 157 A-hr/kg. The cathode reaction mechanism is supposed to be lithium intercalation between phthalocyanine molecules. The results indicate that these phthalocyanines are promising cathode active materials for lithium secondary batteries.

Tamaki, J.; Yamaji, A.

1982-01-01

161

A graphene functionalized electrochemical aptasensor for selective label-free detection of cancer cells.  

PubMed

Here we report an electrochemical sensor that can realize label-free cancer cell detection using the first clinical trial II used aptamer AS1411 and functionalized graphene. By taking advantages of AS1411 high binding affinity and specificity to the overexpressed nucleolin on the cancer cell surface, our developed electrochemical aptasensor can distinguish cancer cells and normal ones and detect as low as one thousand cells. With DNA hybridization technique, this E-DNA sensor can be regenerated and reusable for cancer cell detection. Our work gives a good example for label-free cancer cell detection based on aptamer and graphene-modified electrode. PMID:21256585

Feng, Lingyan; Chen, Yong; Ren, Jinsong; Qu, Xiaogang

2011-01-22

162

Cycle life test of secondary spacecraft cells  

Microsoft Academic Search

The results of the life cycling program on rechargeable calls are reported. Information on required data, the use of which the data will be put, application details, including orbital description, charge control methods, load rquirements, etc., are given. Cycle tests were performed on 660 sealed, nickel cadmium cells. The cells consisted of seven sample classifications ranging form 3.0 to 20

J. D. Harkness

1980-01-01

163

Electrochemical machining analysis on grid cathode composed of square cells  

NASA Astrophysics Data System (ADS)

During the electrochemical machining (ECM), the cathodes designed by the existing methods are mainly unitary cathodes, which can be only used to produce the workpieces with the same shapes. However, there are few researches on designing cathodes for machining the different workpieces with the different surfaces. This paper presents the grid cathode composed of the square cells to produce the workpieces with different shapes. Three types of the square cells, 2.5 mm×2.5 mm, 3 mm×3 mm, and 4 mm×4 mm, are utilized to construct the plane, the slant, and the blade cathode. The material of the cathode and the anode is CrNi18Ti9, and the ingredient of electrolyte is 15% NaCl and 15% NaNO3. The machining equilibrium machining current and time are acquired and analyzed, the machining process and the workpiece quality are compared between using the grid cathode and the unitary cathode. Moreover, the machining errors on the workpiece surface are measured and analyzed, and the error reasons are traced and discussed to obtain the better surface quality of the workpiece. The experiment and analysis results show that the grid cathode can be used to manufacture the workpieces with complex shapes in certain range of the error. The workpiece quality improves with the size of the square cell being reduced, and if the square element is small enough, the workpiece quality is almost equal to the one machined by the unitary cathode. The proposed research realizes a single cathode machining the different workpieces with the different surfaces.

Lu, Yonghua; Liu, Kai; Zhao, Dongbiao

2013-07-01

164

Stability and function of secondary Th1 memory cells are dependent on the nature of the secondary stimulus.  

PubMed

Following acute infection in some mouse models, CD4+ memory T cells steadily decline over time. Conversely, in humans, CD4+ memory T cells can be maintained for many years at levels similar to CD8+ T cells. Because we previously observed that the longevity of Th1 memory cell survival corresponded to their functional avidity, we hypothesized that secondary challenge, which enriches for high functional avidity Th1 responders, would result in more stable Th1 memory populations. We found that following a heterologous secondary challenge, Th1 memory cells were maintained at stable levels compared with primary Th1 memory cells, showing little to no decline after day 75 postinfection. The improved stability of secondary Th1 memory T cells corresponded to enhanced homeostatic turnover; enhanced trafficking of effector memory Th1 cells to tissue sites of infection, such as the liver; and acquisition or maintenance of high functional avidity following secondary challenge. Conversely, a weaker homologous rechallenge failed to induce a stable secondary Th1 memory population. Additionally, homologous secondary challenge resulted in a transient loss of functional avidity by Th1 memory cells recruited into the secondary response. Our findings suggest that the longevity of Th1 memory T cells is dependent, at least in part, on the combined effects of primary and secondary Ag-driven differentiation. Furthermore, they demonstrate that the quality of the secondary challenge can have profound effects on the longevity and function of the ensuing secondary Th1 memory population. PMID:22844122

Kim, Chulwoo; Jay, David C; Williams, Matthew A

2012-07-27

165

Primary antibody-forming cells and secondary B cells are generated from separate precursor cell subpopulations  

Microsoft Academic Search

Summary Two precursor cell subpopulations have been isolated from the spleen cells of nonimmune mice. The major B cell subpopulation binds high levels of the JllD monoclonal antibody and, upon T cell-dependent an- tigenic stimulation, gives rise to primary antibody- forming cell clones but not secondary B cells. A minority of the lo%-14% of la+ precursors that bind low levels

Phyllis-Jean Linton; Debra J. Decker; Norman R. Klinman

1989-01-01

166

Graphene-based Electrochemical Energy Conversion and Storage: Fuel cells, Supercapacitors and Lithium Ion Batteries  

SciTech Connect

Graphene has attracted extensive research interest due to its strictly 2-dimensional (2D) structure, which results in its unique electronic, thermal, mechanical, and chemical properties and potential technical applications. These remarkable characteristics of graphene, along with the inherent benefits of a carbon material, make it a promising candidate for application in electrochemical energy devices. This article reviews the methods of graphene preparation, introduces the unique electrochemical behavior of graphene, and summarizes the recent research and development on graphene-based fuel cells, supercapacitors and lithium ion batteries. In addition, promising areas are identified for the future development of graphene-based materials in electrochemical energy conversion and storage systems.

Hou, Junbo; Shao, Yuyan; Ellis, Michael A.; Moore, Robert; Yi, Baolian

2011-09-14

167

Evolutionary diversification of secondary mechanoreceptor cells in tunicata  

PubMed Central

Background Hair cells are vertebrate secondary sensory cells located in the ear and in the lateral line organ. Until recently, these cells were considered to be mechanoreceptors exclusively found in vertebrates that evolved within this group. Evidence of secondary mechanoreceptors in some tunicates, the proposed sister group of vertebrates, has recently led to the hypothesis that vertebrate and tunicate secondary sensory cells share a common origin. Secondary sensory cells were described in detail in two tunicate groups, ascidians and thaliaceans, in which they constitute an oral sensory structure called the coronal organ. Among thaliaceans, the organ is absent in salps and it has been hypothesised that this condition is due to a different feeding system adopted by this group of animals. No information is available as to whether a comparable structure exists in the third group of tunicates, the appendicularians, although different sensory structures are known to be present in these animals. Results We studied the detailed morphology of appendicularian oral mechanoreceptors. Using light and electron microscopy we could demonstrate that the mechanosensory organ called the circumoral ring is composed of secondary sensory cells. We described the ultrastructure of the circumoral organ in two appendicularian species, Oikopleura dioica and Oikopleura albicans, and thus taxonomically completed the data collection of tunicate secondary sensory cells. To understand the evolution of secondary sensory cells in tunicates, we performed a cladistic analysis using morphological data. We constructed a matrix consisting of 19 characters derived from detailed ultrastructural studies in 16 tunicate species and used a cephalochordate and three vertebrate species as outgroups. Conclusions Our study clearly shows that the circumoral ring is the appendicularian homologue of the coronal organ of other tunicate taxa. The cladistic analysis enabled us to reconstruct the features of the putative ancestral hair cell in tunicates, represented by a simple monociliated cell. This cell successively differentiated into the current variety of oral mechanoreceptors in the various tunicate lineages. Finally, we demonstrated that the inferred evolutionary changes coincide with major transitions in the feeding strategies in each respective lineage.

2013-01-01

168

Secondary Sphere Formation Enhances the Functionality of Cardiac Progenitor Cells  

PubMed Central

Loss of cardiomyocytes impairs cardiac function after myocardial infarction (MI). Recent studies suggest that cardiac stem/progenitor cells could repair the damaged heart. However, cardiac progenitor cells are difficult to maintain in terms of purity and multipotency when propagated in two-dimensional culture systems. Here, we investigated a new strategy that enhances potency and enriches progenitor cells. We applied the repeated sphere formation strategy (cardiac explant ? primary cardiosphere (CS) formation ? sphere-derived cells (SDCs) in adherent culture condition ? secondary CS formation by three-dimensional culture). Cells in secondary CS showed higher differentiation potentials than SDCs. When transplanted into the infarcted myocardium, secondary CSs engrafted robustly, improved left ventricular (LV) dysfunction, and reduced infarct sizes more than SDCs did. In addition to the cardiovascular differentiation of transplanted secondary CSs, robust vascular endothelial growth factor (VEGF) synthesis and secretion enhanced neovascularization in the infarcted myocardium. Microarray pathway analysis and blocking experiments using E-selectin knock-out hearts, specific chemicals, and small interfering RNAs (siRNAs) for each pathway revealed that E-selectin was indispensable to sphere initiation and ERK/Sp1/VEGF autoparacrine loop was responsible for sphere maturation. These results provide a simple strategy for enhancing cellular potency for cardiac repair. Furthermore, this strategy may be implemented to other types of stem/progenitor cell-based therapy.

Cho, Hyun-Jai; Lee, Ho-Jae; Youn, Seock-Won; Koh, Seok-Jin; Won, Joo-Yun; Chung, Yeon-Ju; Cho, Hyun-Ju; Yoon, Chang-Hwan; Lee, Sae-Won; Lee, Eun Ju; Kwon, Yoo-Wook; Lee, Hae-Young; Lee, Sang Hun; Ho, Won-Kyung; Park, Young-Bae; Kim, Hyo-Soo

2012-01-01

169

Measuring fundamental properties in operating solid oxide electrochemical cells by using in situ X-ray photoelectron spectroscopy  

Microsoft Academic Search

Photoelectron spectroscopic measurements have the potential to provide detailed mechanistic insight by resolving chemical states, electrochemically active regions and local potentials or potential losses in operating solid oxide electrochemical cells (SOCs), such as fuel cells. However, high-vacuum requirements have limited X-ray photoelectron spectroscopy (XPS) analysis of electrochemical cells to ex situ investigations. Using a combination of ambient-pressure XPS and CeO2-x\\/YSZ\\/Pt

Chunjuan Zhang; Michael E. Grass; Anthony H. McDaniel; Steven C. Decaluwe; Farid El Gabaly; Zhi Liu; Kevin F. McCarty; Roger L. Farrow; Mark A. Linne; Zahid Hussain; Gregory S. Jackson; Hendrik Bluhm; Bryan W. Eichhorn

2010-01-01

170

Electrochemical properties of Ni–YSZ cermet in solid oxide fuel cells  

Microsoft Academic Search

The effects of various current collectors on the electrochemical property measurements of a Ni–YSZ cermet have been investigated. Electrochemical characteristics were determined by impedance spectroscopy (IS) at open-circuit voltage in H2–H2O atmosphere at 800°C using a symmetrical cell. We selected various current collectors made of gold, platinum and nickel and with two different structures, paste and mesh. When using paste,

M Guillodo; P Vernoux; J Fouletier

2000-01-01

171

Electrical and electrochemical performance characteristics of small commercial Li-ion cells  

Microsoft Academic Search

Advanced rechargeable lithium-ion batteries are presently being developed and commercialized worldwide for use in consumer electronics, military and space applications. At Sandia National Laboratories, the authors have used different electrochemical techniques such as impedance and charge\\/discharge at ambient and subambient temperatures to probe the various electrochemical processes that are occurring in Li-ion cell. The purpose of this study is to

G. Nagasubramanian; E. P. Roth; D. Ingersoll

1999-01-01

172

Electrical and Electrochemical Performance Characteristics of Small Commercial Li-Ion Cells  

Microsoft Academic Search

Advanced rechargeable lithium-ion batteries are presently being developed and commercialized worldwide for use in consumer electronics, military and space applications. At Sandia National Laboratories we have used different electrochemical techniques such as impedance and charge\\/discharge at ambient and subambient temperatures to probe the various electrochemical processes that are occurring in Li-ion cell. The purpose of this study is to identify

D. Ingersoll; G. Nagasubramanian; E. P. Roth

1998-01-01

173

Electrochemical photovoltaic cells. Quarterly technical progress report, August 1-October 31, 1980  

SciTech Connect

Liquid-junction photoelectrochemical cells can be used either for the direct conversion of solar energy to electricity or to generate stored chemical species available for later electrochemical discharge. The objective of this program is to identify experimental approaches for electrochemical photovoltaic cells that not only show promise of high power-conversion efficiencies but also have the potential to achieve long life and the capacity for energy storage. The work is organized as follows: (1) selection of high-efficiency semiconductor photoelectrode/electrolyte systems; (2) development of long-life electrochemical photovoltaic cells; (3) development of an all solid-state electrochemical photovoltaic cell with in-situ storage; and (4) demonstration of laboratory-size photoelectrochemical cell with redox storage. This program is directed toward identifying a suitable match between the proposed semiconductor and the redox species present in aqueous, nonaqueous, and solid electrolytes for achieving the necessary performance and semiconductor stability requirements. Emphasis is on aqueous electrolyte-based systems where fast kinetics are favored. The proposed systems will be compatible with convenient storage of the electroactive species generated and their later electrochemical discharge in a redox cell.

Ang, P. G.P.; Sammells, A. F.

1980-12-01

174

Cellulose Synthesis in the Arabidopsis Secondary Cell Wall  

Microsoft Academic Search

The identification of genes responsible for cellulose synthesis has led to a significant advance in our understanding of the production of this important polymer. The identification of these genes has been possible due to the isolation of cellulose deficient mutants. The irregular xylem (irx) mutants of Arabidopsis are caused by a severe reduction in cellulose synthesis in the secondary cell

NEIL G. TAYLOR; SIMON R. TURNER

175

Cellulose synthesis in the Arabidopsis secondary cell wall  

Microsoft Academic Search

The identification of genes responsible for cellulose synthesis has led to a significant advance in our understanding of the synthesis of this important polymer. The identification of these genes has arisen from the identification of cellulose deficient mutants. The irregular xylem (irx) mutants of Arabidopsis are caused by a severe reduction in cellulose synthesis in the secondary cell wall. Three

Neil G. Taylor; John C. Gardiner; Raymond Whiteman; Simon R. Turner

2004-01-01

176

Catch and release cell sorting: electrochemical desorption of T-cells from antibody-modified microelectrodes.  

PubMed

The development of integrated microsystems capable of interrogation, characterization and sorting of mammalian cells is highly significant for further advancement of point-of-care diagnostics and drug discovery fields. The present study sought to design a novel strategy for releasing antibody-bound cells through electrochemical disruption of the underlying antibody (Ab) layer. A microsystem for selective capture and release of cells consisted of an array of individually addressable gold microelectrodes fabricated on a glass substrate. Poly(ethylene glycol) (PEG) hydrogel photolithography was employed to make the glass regions non-fouling, thus, ensuring selective localization of proteins and cells on the microelectrodes. The gold surfaces were decorated with anti-CD4 Ab molecules using standard alkanethiol self-assembly and carbodiimide coupling approaches. The Ab-functionalized electrodes selectively captured model T-lymphocytes (Molt-3 cells) expressing CD4 antigen while minimal cell adhesion was observed on PEG hydrogel-modified glass substrates. Importantly, application of a reductive potential (-1.2V vs. Ag/AgCl reference electrode) resulted in release of surface-bound T-cells from the electrode surface. Cyclic voltammetry and fluorescence microscopy were employed to verify that the detachment of captured T-cells was indeed due to the electrochemical disruption of the underlying alkanethiol-Ab layer. In the future, the cell sorting approach described here may be combined with microfluidic delivery to enable Ab-mediated capture of T-lymphocytes or other cell types followed by release of select cells for downstream gene expression studies or re-cultivation. PMID:18394868

Zhu, He; Yan, Jun; Revzin, Alexander

2008-03-10

177

Non-Kinetic Losses Caused by Electrochemical Carbon Corrosion in PEM Fuel Cells  

SciTech Connect

This paper presented non-kinetic losses in PEM fuel cells under an accelerated stress test of catalyst support. The cathode with carbon-supported Pt catalyst was prepared and characterized with potential hold at 1.2 V vs. SHE in PEM fuel cells. Irreversible losses caused by carbon corrosion were evaluated using a variety of electrochemical characterizations including cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy, and polarization technique. Ohmic losses at the cathode with potential hold were determined using its capacitive responses. Concentration losses in PEM fuel cells were analyzed in terms of Tafel behavior and thin film/flooded-agglomerate dynamics.

Park, Seh Kyu; Shao, Yuyan; Viswanathan, Vilayanur V.; Liu, Jun; Wang, Yong

2012-05-01

178

Experimental insight into the performance characteristics of Ni-mesh semiconductor photo-electrochemical cells  

Microsoft Academic Search

The performance characteristics of two photo-electrochemical cells with different cell configurations were investigated at 25°C and within the illumination range of 70–100W\\/m2. These cells included a jacketed single cell (JSC) and a jacketed two-compartment cell (JTC). Ni-mesh was used as a counter electrode and as a backing material for semiconductor electrodes. Semiconductor electrodes were prepared by silk-screen painting technique using

?lker Bayer; ?nci Ero?lu; Lemi Türker

2000-01-01

179

Production of Secondary Metabolites Using Plant Cell Cultures  

Microsoft Academic Search

Plant cell cultures represent a potential source of valuable secondary metabolites which can\\u000a be used as food additives, nutraceuticals, and pharmaceuticals. The synthesis of phytochemicals by the\\u000a cell cultures in contrast to these in plants is independent of environmental conditions and quality fluctuations.\\u000a In many cases, the chemical synthesis of metabolites is not possible or economically feasible. Moreover,\\u000a the natural food

Iryna Smetanska

180

Life testing of secondary silver-zinc cells  

Microsoft Academic Search

Testing on a variety of secondary silver-zinc (Ag-Zn) cells has been in progress at the Marshall Space Flight Center (MSFC) for over six years. The latest test involves a 350-Ah cell design that has been cycled at 10 C for 16 months. This design has achieved over 7200 low-earth-orbit (LEO) cycles as well as 17 deep discharges at an 85

Jeffrey C. Brewer; Rajiv Doreswamy

1991-01-01

181

Applications of electrogenerated conducting polymers in electrochemical photovoltaic cells  

SciTech Connect

Results are presented which show that electro-chemically generated conducting polypyrrole films protect n-type semiconductor photoelectrodes from degradation while permitting electron exchange between the semiconductor and the electrolyte. The performance characteristics and stability of such film-covered photoelectrodes are discussed.

Noufi, R.

1982-09-01

182

Electrochemical cell chip to detect environmental toxicants based on cell cycle arrest technique.  

PubMed

A cell-based chip was recently developed and shown to be an effective in vitro tool for analyzing effect of environmental toxin on target cells. However, common cell chips are inappropriate for the detection of multiple environmental toxins. Here, we fabricated a neural cell chip to detect different cellular responses induced by BPA (bisphenol-A) and PCB (poly chlorinated biphenyl). This approach was based on an electrochemical method using a cell cycle-arrest technique. Neural cells were synchronized at the synthesis phase by treatment with thymidine, which results in a sharp reduction peak when compared to unsynchronized cells. The fabricated chip containing 50% G1/S and 50% G2/M phase cells was used to determine the effects of environmental toxins on neural cancer cells. At the end, the cell-chips could be used to assess both BPA and PCB toxicity that the cells were completely synchronized at the G1/S and G2/M phase. The proposed neural cell chip can be a useful tool for biosensors to evaluate easily and sensitively multiple effects of environmental toxicants on target cells. PMID:22959010

Kafi, Md Abdul; Yea, Cheol-Heon; Kim, Tae-Hyung; Yagati, Ajay Kumar; Choi, Jeong-Woo

2012-08-18

183

Diagnostic tools in PEM fuel cell research: Part I Electrochemical techniques  

Microsoft Academic Search

To meet the power density, reliability, and cost requirements that will enable a widespread use of fuel cells, many research activities focus on an understanding of the thermodynamics as well as the fluid mechanical and electrochemical processes within a fuel cell. To date, a wide range of experimental diagnostics is imperative not only to help a fundamental understanding of fuel

Jinfeng Wu; Xiao Zi Yuan; Haijiang Wang; Mauricio Blanco; Jonathan J. Martin; Jiujun Zhang

2008-01-01

184

Meniscus confined fabrication of multidimensional conducting polymer nanostructures with scanning electrochemical cell microscopy (SECCM).  

PubMed

Scanning electrochemical cell microscopy (SECCM) is demonstrated as a new approach for the construction of extended multi-dimensional conducting polymer (polyaniline) nanostructures, making use of a mobile dual-channel theta pipette cell to control and monitor the location, rate and extent of electropolymerisation. PMID:23459882

McKelvey, Kim; O'Connell, Michael A; Unwin, Patrick R

2013-04-14

185

Electrochemical Polishing of Silverware: A Demonstration of Voltaic and Galvanic Cells  

ERIC Educational Resources Information Center

In this demonstration, the students use their knowledge of electrochemistry to determine that tarnish can be removed from silverware by electrochemically converting it back to silver using items commonly available in the kitchen: aluminum foil and baking soda. In addition to using this system as an example of a galvanic cell, an electrolytic cell…

Ivey, Michelle M.; Smith, Eugene T.

2008-01-01

186

Electrochemical Polishing of Silverware: A Demonstration of Voltaic and Galvanic Cells  

ERIC Educational Resources Information Center

|In this demonstration, the students use their knowledge of electrochemistry to determine that tarnish can be removed from silverware by electrochemically converting it back to silver using items commonly available in the kitchen: aluminum foil and baking soda. In addition to using this system as an example of a galvanic cell, an electrolytic cell…

Ivey, Michelle M.; Smith, Eugene T.

2008-01-01

187

Safranine T dye based photo electrochemical solar cell: Effect of electrodes on device mechanism  

Microsoft Academic Search

We made two photovoltaic devices using blend of Safranine T dye in a thin film of polyvinyl alcohol mixed with solid electrolyte made by PEO and LiClO4, placed between two electrodes, resulting photo electrochemical cell (PEC) structure. One of the cells made of two ITO coated glass plates as electrodes and the other with ITO and Silver. The current voltage

Subhasis Maity; Nabin Baran Manik

2007-01-01

188

In situ solid-state NMR spectroscopy of electrochemical cells: batteries, supercapacitors, and fuel cells.  

PubMed

Electrochemical cells, in the form of batteries (or supercapacitors) and fuel cells, are efficient devices for energy storage and conversion. These devices show considerable promise for use in portable and static devices to power electronics and various modes of transport and to produce and store electricity both locally and on the grid. For example, high power and energy density lithium-ion batteries are being developed for use in hybrid electric vehicles where they improve the efficiency of fuel use and help to reduce greenhouse gas emissions. To gain insight into the chemical reactions involving the multiple components (electrodes, electrolytes, interfaces) in the electrochemical cells and to determine how cells operate and how they fail, researchers ideally should employ techniques that allow real-time characterization of the behavior of the cells under operating conditions. This Account reviews the recent use of in situ solid-state NMR spectroscopy, a technique that probes local structure and dynamics, to study these devices. In situ NMR studies of lithium-ion batteries are performed on the entire battery, by using a coin cell design, a flat sealed plastic bag, or a cylindrical cell. The battery is placed inside the NMR coil, leads are connected to a potentiostat, and the NMR spectra are recorded as a function of state of charge. (7)Li is used for many of these experiments because of its high sensitivity, straightforward spectral interpretation, and relevance to these devices. For example, (7)Li spectroscopy was used to detect intermediates formed during electrochemical cycling such as LixC and LiySiz species in batteries with carbon and silicon anodes, respectively. It was also used to observe and quantify the formation and growth of metallic lithium microstructures, which can cause short circuits and battery failure. This approach can be utilized to identify conditions that promote dendrite formation and whether different electrolytes and additives can help prevent dendrite formation. The in situ method was also applied to monitor (by (11)B NMR) electrochemical double-layer formation in supercapacitors in real time. Though this method is useful, it comes with challenges. The separation of the contributions from the different cell components in the NMR spectra is not trivial because of overlapping resonances. In addition, orientation-dependent NMR interactions, including the spatial- and orientation-dependent bulk magnetic susceptibility (BMS) effects, can lead to resonance broadening. Efforts to understand and mitigate these BMS effects are discussed in this Account. The in situ NMR investigation of fuel cells initially focused on the surface electrochemistry at the electrodes and the electrochemical oxidation of methanol and CO to CO2 on the Pt cathode. On the basis of the (13)C and (195)Pt NMR spectra of the adsorbates and electrodes, CO adsorbed on Pt and other reaction intermediates and complete oxidation products were detected and their mode of binding to the electrodes investigated. Appropriate design and engineering of the NMR hardware has allowed researchers to integrate intact direct methanol fuel cells into NMR probes. Chemical transformations of the circulating methanol could be followed and reaction intermediates could be detected in real time by either (2)H or (13)C NMR spectroscopy. By use of the in situ NMR approach, factors that control fuel cell performance, such as methanol cross over and catalyst performance, were identified. PMID:24041242

Blanc, Frédéric; Leskes, Michal; Grey, Clare P

2013-06-21

189

Cell and current collector felt arrangement for solid oxide electrochemical cell combinations  

DOEpatents

A solid electrolyte electrochemical cell combination 1 is made, comprising an annular, axially elongated, inner electrode 2 containing at least one interior gas feed conduit 3; annular solid electrolyte segments 4 around and covering portions of the inner electrode; annular outer electrode segments 6 around and covering portions of the electrolyte segments; electronically conducting, non-porous, interconnection material 5 disposed between electrolyte segments and in contact with the inner electrode, and electronically conducting, porous, metal fiber current collector felts 7 disposed on top of the non-porous interconnect material and outer electrode segments, where both the non-porous interconnect material and the porous metal felts are disposed circumferentially about the cell, transversely to the axial length of the cell and the inner electrode is continuous for the entire axial length of the cell combination.

Reichner, Philip (Plum Boro, PA)

1988-01-01

190

Electrochemical immunoassay on expression of integrin ?1 on tumor cells and drug-resistant tumor cells.  

PubMed

An electrochemical indirect competitive immunoassay protocol as a promising cytosensing strategy was developed to detect integrin ?1 expression on human breast cancer MCF-7 cells and adriamycin-resistant human breast cancer MCF-7 (MCF-7/ADR) cells and quantify the cell number. Integrin ?5?1 was adsorbed on the gold-nanoparticle modified glassy carbon electrode to bind integrin ?1 monoclonal antibody (anti-CD29 mAb). A sandwich structure was then formed using nanocomposites which consisted of horseradish peroxidase (HRP) labeled anti-antibody and gold nanoparticles. HRP bound on the electrode surface could cause an amperometric response of the hydroquinone-H(2)O(2) system. The assembly of the sandwich structure was inhibited by tumor cells to give decreased enzyme-catalytic signals due to the capture of anti-CD29 mAb by integrin ?1 on cell membranes. Under optimal conditions the relative current change (S) was proportional to the cell concentration from 1.6 × 10(3) to 2.0 × 10(6) cells mL(-1) with a detection limit of 700 cells mL(-1). Integrin ?1 expression in MCF-7/ADR cells was found to be significantly higher than that in MCF-7 cells, indicating the increased adhesion ability of MCF-7/ADR cells. PMID:22776180

Zhou, Bei; Xiao, Xiuli; Xu, Lili; Zhu, Lian; Tan, Liang; Tang, Hao; Zhang, Youyu; Xie, Qingji; Yao, Shouzhuo

2012-06-28

191

Overcharge and overdischarge protection of ambient temperature secondary lithium cells  

NASA Astrophysics Data System (ADS)

A cathode additive is provided for protecting an ambient temperature secondary lithium cell from overcharging or overdischarging. The cathode additive is chosen to create an upper voltage plateau which is slightly higher than a characteristic charge cutoff voltage of the cathode of the cell. The cathode additive additionally creates a lower voltage plateau which is slightly lower than the characteristic discharge cutoff voltage of the cell. Preferably, the cathode additive is a transition metal oxide or a sulfide and may, for example, include a mixture of Li2Mn2O4 and Li(0.1)MoO2.

Huang, Chen-Kuo; Surampudi, Subbarao; Attia, Alan I.; Halpert, Gerald

1994-01-01

192

Nano-Bio Electrochemical Interfacing-Linking Cell Biology and Micro-Electronics  

NASA Astrophysics Data System (ADS)

Integration of biological substance within electronic devices is an innovative and challenging area combining recent progress in molecular biology and micro technology. First, we introduce the concept of integrating living cells with Micro Electro Mechanical Systems (MEMS). Following a brief overview on "whole cell based biosensors" we describe the design, fabrication, and process of a biocompatible electrochemical "Lab-on-a-Chip" system. Demonstrating the application of electrochemical interfacing based whole cell bio chips, we present two different configurations: a. integration of prokaryotic cells (bacteria) for water toxicity detection, and b. integration of eukaryotic cells (human colon cancer cells) for rapid evaluation of the effectiveness of drug treatments. Both applications, with either microbes or mammalian cells integrated onto MEMS based biochips with liquid volume in the range of 100 nL-1 ?L, function well and yield a detectable signal much higher than noise level after few minutes.

Shacham-Diamand, Y.; Popovtzer, R.; Rishpon, Y.

193

Electrochemical behavior of CrN coating for polymer electrolyte membrane fuel cell  

NASA Astrophysics Data System (ADS)

CrN films on a bipolar plate in polymer electrolyte membrane fuel cells have several advantages owing to their excellent corrosion resistance and mechanical properties. Three CrN samples deposited at various radio frequency (RF) powers by RF magnetron sputtering were evaluated under potentiodynamic, potentiostatic and electrochemical impedance spectroscopy conditions. The electrochemical impedance spectroscopy data were monitored for 168 h in a corrosive environment at 70 °C to determine the coating performance at +600 mVSCE under simulated cathodic conditions in a polymer electrolyte membrane fuel cell. The electrochemical behavior of the coatings increased with decreasing RF power. CrN films on the AISI 316 stainless steel substrate showed high protective efficiency and charge transfer resistance, i.e. increasing corrosion resistance with decreasing RF power. X-ray diffraction confirmed the formation of a CrN(200) preferred orientation at low RF power.

Nam, N. D.; Park, I. J.; Kim, J. G.; Tai, P. H.; Yoon, D. H.

2010-05-01

194

Secondary failure of platelet recovery after hematopoietic stem cell transplantation  

Microsoft Academic Search

After primary recovery of platelet counts after transplantation, there can be a late persistent decline called secondary failure of platelet recovery (SFPR), which may occur although the counts of other cell lineages remain within the normal range. SFPR was defined as a decline of platelet counts below 20,000\\/microL for 7 consecutive days or requiring transfusion support after achieving sustained platelet

Benedetto Bruno; Theodore Gooley; Keith M Sullivan; Chris Davis; William I Bensinger; Rainer Storb; Richard A Nash

2001-01-01

195

The electrochemical intercalation of Li into graphite in Li\\/polymer electrolyte\\/graphite cells  

Microsoft Academic Search

The electrochemical intercalation of Li into graphite has been studied in Li\\/polymer electrolyte\\/graphite cells using an in situ X-ray diffraction (XRD) technique. In cells containing an electrolyte of PAN (polyacrylonitrile)-EC (ethylene carbonate)-LiPFâ, a minor irreversible reduction of the electrolyte is observed only during the first discharge. In these cells, Li is reversibly intercalated into graphite to form Li{sub 1.0}Câ, principally

Z. Jiang; M. Alamgir; K. M. Abraham

1995-01-01

196

Electrochemical properties of Zn\\/orange dye aqueous solution\\/carbon cell  

Microsoft Academic Search

An investigation is made of the electrochemical properties of a Zn\\/orange dye aqueous solution\\/carbon cell. In this cell, a solution of 3wt.% orange dye (C17H17N5O2) in distilled water is used as the electrolyte and zinc and carbon rods serve as electrodes. The cell is fabricated in a cylindrical glass vessel and has a length and a diameter of 4 and

Khasan S. Karimov; Muhammad H. Sayyad; Mukhtar Ali; Muhammad N. Khan; Syed A. Moiz; Khurram B. Khan; Humera Farah; Zioda M. Karieva

2006-01-01

197

Sulfur tolerant composite cermet electrodes for solid oxide electrochemical cells  

DOEpatents

An electrochemical apparatus is made containing an exterior electrode bonded to the exterior of a tubular, solid, oxygen ion conducting electrolyte where the electrolyte is also in contact with an interior electrode, said exterior electrode comprising particles of an electronic conductor contacting the electrolyte, where a ceramic metal oxide coating partially surrounds the particles and is bonded to the electrolyte, and where a coating of an ionic-electronic conductive material is attached to the ceramic metal oxide coating and to the exposed portions of the particles.

Isenberg, Arnold O. (Pittsburgh, PA)

1987-01-01

198

High strength porous support tubes for high temperature solid electrolyte electrochemical cells  

DOEpatents

A high temperature, solid electrolyte electrochemical cell is made, having an electrode and a solid electrolyte disposed on a porous, sintered support material containing thermally stabilized zirconia powder particles and from about 3 wt. % to about 45 wt. % of thermally stable oxide fibers.

Rossing, Barry R. (Churchill, PA); Zymboly, Gregory E. (Penn Hills, PA)

1986-01-01

199

The Effect of Supplementing Instruction with Conceptual Change Texts on Students' Conceptions of Electrochemical Cells  

ERIC Educational Resources Information Center

The aim of this study was to investigate the effectiveness of instruction supplemented by conceptual change texts (CCTs) over traditional instruction on students' understanding of electrochemical (galvanic and electrolytic) cell concepts. The participants of the study consisted of 64 students from the two classes of a high school located in…

Yuruk, Nejla

2007-01-01

200

Conceptual Change Text: A Supplementary Material To Facilitate Conceptual Change in Electrochemical Cell Concepts.  

ERIC Educational Resources Information Center

The main purpose of the study was to investigate the effectiveness of conceptual change text (CCT) oriented instruction over traditionally designed instruction on students' understanding of electrochemical (galvanic and electrolytic) cell concepts. The subjects of the study consisted of 64 students from the two classes of a high school in Turkey.…

Yuruk, Nejla; Geban, Omer

201

Method for the manufacture of an electrochemical cell or battery and battery made by the method  

Microsoft Academic Search

The invention relates to a method for the manufacture of an electrochemical cell or battery, consisting of a stack of plateshaped elements, each of which consists of a sheet or plate of electrode material which is mounted in a frame made of electrically insulating fibrous-web material impregnated with a non-polymerized thermosetting synthetic material, which elements in a first compression molding

Dorrestijn

1980-01-01

202

Electrochemical DeNO x in solid electrolyte cells—an overview  

Microsoft Academic Search

The investigations in the field of electrochemical reduction of nitric oxide are reviewed. Using a cell based on an oxide ionic conductor it is shown that the selectivity and activity of the cathodes is strongly dependent on the temperature and of the composition of the cathode material. In general the selectivity is highest at the lowest temperatures. Cathode materials with

K. Kammer

2005-01-01

203

An electrochemical-based fuel-cell model suitable for electrical engineering automation approach  

Microsoft Academic Search

This paper presents a dynamic electrochemical model for representation, simulation, and evaluation of performance of small size generation systems emphasizing particularly proton exchange membrane fuel-cell (PEMFC) stacks. The results of the model are used to predict the output voltage, efficiency, and power of FCs as a function of the actual load current and of the constructive and operational parameters of

Jeferson M. Corrêa; Felix A. Farret; Luciane N. Canha; Marcelo G. Simões

2004-01-01

204

Comparison of High-Throughput Electrochemical Methods for Testing Direct Methanol Fuel Cell Anode Electrocatalysts  

Microsoft Academic Search

The screening and testing of fuel cell electrocatalysts often involves comparisons under conditions that do not closely match their use in membrane electrode assemblies. We compared the activities of several commercial and homemade Pt and PtRu catalysts for electrochemical methanol oxidation by four different techniques; disk electrode linear sweep voltammetry in aqueous methanol\\/ sulfuric acid solutions, optical fluorescence detection in

Benny C. Chan; Renxuan Liu; Krishnakumar Jambunathan; Hong Zhangc; Guoying Chen; Thomas E. Mallouk; Eugene S. Smotkinb

2005-01-01

205

Palladium deuteride formation in the cathode of an electrochemical cell: An in situ neutron diffraction study  

SciTech Connect

In this report, neutron diffraction of palladium cathodes is utilized to reveal palladium deuteride formation within the crystal structure of the metal. The experiment described in this report demonstrates the efficacy of neutron powder diffraction as a tool for structural studies of metal deuterides/hydrides and the feasibility of in situ diffraction measurements from a working electrochemical cell. (JL)

Rotella, F.J.; Richardson, J.W. Jr.; Redey, L.; Felcher, G.P.; Hitterman, R.L.; Kleb, R.

1991-01-01

206

Palladium deuteride formation in the cathode of an electrochemical cell: An in situ neutron diffraction study  

SciTech Connect

In this report, neutron diffraction of palladium cathodes is utilized to reveal palladium deuteride formation within the crystal structure of the metal. The experiment described in this report demonstrates the efficacy of neutron powder diffraction as a tool for structural studies of metal deuterides/hydrides and the feasibility of in situ diffraction measurements from a working electrochemical cell. (JL)

Rotella, F.J.; Richardson, J.W. Jr.; Redey, L.; Felcher, G.P.; Hitterman, R.L.; Kleb, R.

1991-12-31

207

The Effect of Supplementing Instruction with Conceptual Change Texts on Students' Conceptions of Electrochemical Cells  

ERIC Educational Resources Information Center

|The aim of this study was to investigate the effectiveness of instruction supplemented by conceptual change texts (CCTs) over traditional instruction on students' understanding of electrochemical (galvanic and electrolytic) cell concepts. The participants of the study consisted of 64 students from the two classes of a high school located in…

Yuruk, Nejla

2007-01-01

208

Imaging the doping and electroluminescence in extremely large planar polymer light-emitting electrochemical cells  

Microsoft Academic Search

An extremely large planar polymer light-emitting electrochemical cell with an interelectrode spacing of 11 mm has been demonstrated. The large planar device structure allows for the imaging of doping propagation, photoluminescence, and electroluminescence (EL) with high spatial and temporal resolutions. Several unconventional EL modes have been observed based on the direct imaging of these devices with an interelectrode spacing ranging

Jun Gao; Justin Dane

2005-01-01

209

A novel aptamer-based competition strategy for ultrasensitive electrochemical detection of leukemia cells.  

PubMed

A robust, nanobiotechnology-based electrochemical cytosensing platform for the detection of acute leukemia cells was developed with high sensitivity, selectivity, acceptable rapidity and excellent extensibility. It utilized the competitive binding of cell-specific aptamers to acute leukemia cells and subsequent voltammetric quantification of the metal signature. Greatly enhanced sensitivity was achieved with dual signal amplification by using Fe3O4 magnetic nanoparticles (MNPs) as carriers to load a large amount of gold nanoparticles (AuNPs) and AuNP-catalyzed silver deposition. The proposed competitive cytosensor showed high sensitivity with a detection limit down to 10 cells. This simple and low-cost electrochemical cytosensing approach offers great promise to extend its application to early detection of human leukemia and possibly to other cancer cells. PMID:23978949

Zhang, Kui; Tan, Tingting; Fu, Jia-Ju; Zheng, Tingting; Zhu, Jun-Jie

2013-09-30

210

Design, evaluation, and application of continuous flow cells for organic electrochemical synthesis. Progress report  

SciTech Connect

The strategy of paired electrochemical synthesis for the production of organic chemicals can result in as much as a 50% reduction in energy consumption, as compared to conventional electroorganic synthesis. A continuation of the research in paired synthesis, presently being conducted in this laboratory, is proposed. The future proposed work includes: (1) A continuing investigation into the chemistry of paired electroorganic reactions; (2) The engineering analysis and design of the electrochemical flow cell and separation equipment required for a synthesis; and (3) A bench scale pilot plant study and economic analysis of a synthesis.

Nobe, K.

1982-03-01

211

Method of bonding an interconnection layer on an electrode of an electrochemical cell  

DOEpatents

An electrochemical cell containing an air electrode (16), contacting electrolyte and electronically conductive interconnection layer (26), and a fuel electrode, has the interconnection layer (26) attached by: (A) applying a thin, closely packed, discrete layer of LaCrO.sub.3 particles (30), doped with an element selected from the group consisting of Ca, Sr, Co, Ba, Mg and their mixtures on a portion of the air electrode, and then (B) electrochemical vapor depositing a dense skeletal structure (32) between and around the doped LaCrO.sub.3 particles (30).

Pal, Uday B. (Cambridge, MA); Isenberg, Arnold O. (Pittsburgh, PA); Folser, George R. (Lower Burrell, PA)

1992-01-01

212

Method of bonding an interconnection layer on an electrode of an electrochemical cell  

DOEpatents

An electrochemical cell containing an air electrode, contacting electrolyte and electronically conductive interconnection layer, and a fuel electrode, has the interconnection layer attached by: (A) applying a thin, closely packed, discrete layer of LaCrO[sub 3] particles, doped with an element selected from the group consisting of Ca, Sr, Co, Ba, Mg and their mixtures on a portion of the air electrode, and then (B) electrochemical vapor depositing a dense skeletal structure between and around the doped LaCrO[sub 3] particles. 2 figs.

Pal, U.B.; Isenberg, A.O.; Folser, G.R.

1992-01-14

213

Combinatorial electrochemical cell array for high throughput screening of micro-fuel-cells and metal/air batteries  

NASA Astrophysics Data System (ADS)

An electrochemical cell array was designed that contains a common air electrode and 16 microanodes for high throughput screening of both fuel cells (based on polymer electrolyte membrane) and metal/air batteries (based on liquid electrolyte). Electrode materials can easily be coated on the anodes of the electrochemical cell array and screened by switching a graphite probe from one cell to the others. The electrochemical cell array was used to study direct methanol fuel cells (DMFCs), including high throughput screening of electrode catalysts and determination of optimum operating conditions. For screening of DMFCs, there is about 6% relative standard deviation (percentage of standard deviation versus mean value) for discharge current from 10 to 20 mA/cm2. The electrochemical cell array was also used to study tin/air batteries. The effect of Cu content in the anode electrode on the discharge performance of the tin/air battery was investigated. The relative standard deviations for screening of metal/air battery (based on zinc/air) are 2.4%, 3.6%, and 5.1% for discharge current at 50, 100, and 150 mA/cm2, respectively.

Jiang, Rongzhong

2007-07-01

214

Scanning Electrochemical Cell Microscopy: A Versatile Technique for Nanoscale Electrochemistry and Functional Imaging  

NASA Astrophysics Data System (ADS)

Scanning electrochemical cell microscopy (SECCM) is a new pipette-based imaging technique purposely designed to allow simultaneous electrochemical, conductance, and topographical visualization of surfaces and interfaces. SECCM uses a tiny meniscus or droplet, at the end of a double-barreled (theta) pipette, for high-resolution functional imaging and nanoscale electrochemical measurements. Here we introduce this technique and provide an overview of its principles, instrumentation, and theory. We discuss the power of SECCM in resolving complex structure-activity problems and provide considerable new information on electrode processes by referring to key example systems, including graphene, graphite, carbon nanotubes, nanoparticles, and conducting diamond. The many longstanding questions that SECCM has been able to answer during its short existence demonstrate its potential to become a major technique in electrochemistry and interfacial science.

Ebejer, Neil; Güell, Aleix G.; Lai, Stanley C. S.; McKelvey, Kim; Snowden, Michael E.; Unwin, Patrick R.

2013-06-01

215

Improvement of electrochemical performance of all-solid-state lithium secondary batteries by surface modification of LiMn 2O 4 positive electrode  

Microsoft Academic Search

To improve the electrochemical performance of an all-solid-state In\\/80Li2S?20P2S5 (electrolyte)\\/LiMn2O4 cell, a lithium-titanate thin film was used to coat LiMn2O4. The interfacial resistance between LiMn2O4 and the electrolyte (measured after initial charging) decreased when the LiMn2O4 particles were coated with lithium-titanate. A cell with lithium-titanate-coated LiMn2O4 had a higher capacity than a cell with noncoated LiMn2O4 for current densities in

Hirokazu Kitaura; Akitoshi Hayashi; Kiyoharu Tadanaga; Masahiro Tatsumisago

2011-01-01

216

Scanning electrochemical microscopy of menadione-glutathione conjugate export from yeast cells  

PubMed Central

The uptake of menadione (2-methyl-1,4-naphthoquinone), which is toxic to yeast cells, and its expulsion as a glutathione complex were studied by scanning electrochemical microscopy. The progression of the in vitro reaction between menadione and glutathione was monitored electrochemically by cyclic voltammetry and correlated with the spectroscopic (UV–visible) behavior. By observing the scanning electrochemical microscope tip current of yeast cells suspended in a menadione-containing solution, the export of the conjugate from the cells with time could be measured. Similar experiments were performed on immobilized yeast cell aggregates stressed by a menadione solution. From the export of the menadione-glutathione conjugate detected at a 1-?m-diameter electrode situated 10 ?m from the cells, a flux of about 30,000 thiodione molecules per second per cell was extracted. Numerical simulations based on an explicit finite difference method further revealed that the observation of a constant efflux of thiodione from the cells suggested the rate was limited by the uptake of menadione and that the efflux through the glutathione-conjugate pump was at least an order of magnitude faster.

Mauzeroll, Janine; Bard, Allen J.

2004-01-01

217

Electroendocytosis is driven by the binding of electrochemically produced protons to the cell's surface.  

PubMed

Electroendocytosis involves the exposure of cells to pulsed low electric field and is emerging as a complementary method to electroporation for the incorporation of macromolecules into cells. The present study explores the underlying mechanism of electroendocytosis and its dependence on electrochemical byproducts formed at the electrode interface. Cell suspensions were exposed to pulsed low electric field in a partitioned device where cells are spatially restricted relative to the electrodes. The cellular uptake of dextran-FITC was analyzed by flow cytometery and visualized by confocal microscopy. We first show that uptake occurs only in cells adjacent to the anode. The enhanced uptake near the anode is found to depend on electric current density rather than on electric field strength, in the range of 5 to 65 V/cm. Electrochemically produced oxidative species that impose intracellular oxidative stress, do not play any role in the stimulated uptake. An inverse dependence is found between electrically induced uptake and the solution's buffer capacity. Electroendocytosis can be mimicked by chemically acidifying the extracellular solution which promotes the enhanced uptake of dextran polymers and the uptake of plasmid DNA. Electrochemical production of protons at the anode interface is responsible for inducing uptake of macromolecules into cells exposed to a pulsed low electric field. Expanding the understanding of the mechanism involved in electric fields induced drug-delivery into cells, is expected to contribute to clinical therapy applications in the future. PMID:23209699

Ben-Dov, Nadav; Rozman Grinberg, Inna; Korenstein, Rafi

2012-11-27

218

Characterization of endothelial cells using electrochemical impedance spectroscopy  

Microsoft Academic Search

In this paper we report on the electrical impedance spectroscopy characterization of endothelial cell lines (RFPEC). For electrical cell-substrate impedance sensing (ECIS) of the endothelial cells a commercially available eight-well cell culture impedance array (ECIS-8W1E) was used. The impedance measurements were recorded with cell culture medium (without cells) and with endothelial cell layer in the culture medium over a frequency

Fei Liu; S. M. Arifuzzaman; A. N. Nordin; D. Spray; I. Voiculescu

2010-01-01

219

Electrical and Electrochemical Performance Characteristics of Large Capacity Li-Ion Cells  

SciTech Connect

We are currently evaluating large capacity (20 - 40 Ah) Bluestar (cylindrical) and Yardney (prismatic) Li-ion cells for their electrical and electrochemical performance characteristics at different temperatures. The cell resistance was nearly constant from room temperature to -20{degrees}C but increased by over 10 times at -40{degrees}C. The specific energy and power as well as the energy density and power density are high and didn't reach a plateau even at the highest discharge rates tested. For example, the prismatic Li-ion cells gave close to 280 Wh l{sup -1} at 4-amp discharge and 249 Wh l{sup -1} at 20-amp discharge at room temperature. For the same current range the specific power values are 102 Wh kg{sup -1} and 91 Wh kg{sup -1}. Cycle life and other electrical and electrochemical properties of the cells will be presented.

Doughty, I.D.; Hill, C.; Ingersoll, D.; Marsh, C.; Nagasubramanian, G.; Radzykewycz, D

1998-12-01

220

Method of making an electrolyte for an electrochemical cell  

DOEpatents

Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode. Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between {minus}15 C and 150 C. 9 figs.

Bates, J.B.; Dudney, N.J.

1996-04-30

221

Method of making an electrolyte for an electrochemical cell  

DOEpatents

Described is a thin-film battery, especially a thin-film microbattery, and a method for making same having application as a backup or primary integrated power source for electronic devices. The battery includes a novel electrolyte which is electrochemically stable and does not react with the lithium anode and a novel vanadium oxide cathode Configured as a microbattery, the battery can be fabricated directly onto a semiconductor chip, onto the semiconductor die or onto any portion of the chip carrier. The battery can be fabricated to any specified size or shape to meet the requirements of a particular application. The battery is fabricated of solid state materials and is capable of operation between -15.degree. C. and 150.degree. C.

Bates, John B. (Oak Ridge, TN); Dudney, Nancy J. (Knoxville, TN)

1996-01-01

222

Overcharge and overdischarge protection of ambient temperature secondary lithium cells  

SciTech Connect

A cathode additive is provided for protecting an ambient temperature secondary lithium cell from over-charging or over-discharging. The cathode additive is chosen to create an upper voltage plateau which is slightly higher than a characteristic charge cutoff voltage of the cathode of the cell. The cathode additive additionally creates a lower voltage plateau which is slightly lower than the characteristic discharge cutoff voltage of the cell. Preferably the cathode additive is a transition metal oxide or a sulfide and may, for example, include a mixture of Li[sub 2]Mn[sub 2]O[sub 4] and Li[sub 0.1]MoO[sub 2]. 4 figs.

Huang, C.K.; Surampudi, S.; Attia, A.I.; Halpert, G.

1994-01-11

223

Characterization of a stirred tank electrochemical cell for water disinfection processes  

Microsoft Academic Search

Laboratory experiments were performed to characterize the behaviour of an electrochemical cell equipped with boron-doped diamond anodes and to verify its effectiveness in water disinfection. The hydrodynamic regime was determined when the cell worked either in batch or in continuous mode. Galvanostatic electrolyses of aqueous 1mM Na2SO4 solutions were performed to investigate on the oxidant production in different experimental conditions.

A. M. Polcaro; A. Vacca; M. Mascia; S. Palmas; R. Pompei; S. Laconi

2007-01-01

224

Effects of synthesis temperature on the electrochemical characteristics of pyrolytic carbon for anodes of lithium-ion secondary batteries  

Microsoft Academic Search

The electrochemical properties of new disordered carbon materials obtained by a gas-phase reaction of LPG (liquid propane gas) have been studied. Pyrolysis of LPG was performed in the temperature range 900 to 1,200 C. The lithium storage mechanism in these disordered carbons has been investigated by the charge-discharge tester, cyclic voltammeter, X-ray diffraction (XRD), solid-state ⁷Li nuclear magnetic resonance (NMR),

Young-Soo Han; J. S. Yu; G. S. Park; J. Y. Lee

1999-01-01

225

Electroporation followed by electrochemical measurement of quantal transmitter release from single cells using a patterned microelectrode.  

PubMed

An electrochemical microelectrode located immediately adjacent to a single neuroendocrine cell can record spikes of amperometric current that result from exocytosis of oxidizable transmitter from individual vesicles, i.e., quantal exocytosis. Here, we report the development of an efficient method where the same electrochemical microelectrode is used to electropermeabilize an adjacent chromaffin cell and then measure the consequent quantal catecholamine release using amperometry. Trains of voltage pulses, 5-7 V in amplitude and 0.1-0.2 ms in duration, were used to reliably trigger release from cells using gold electrodes. Amperometric spikes induced by electropermeabilization had similar areas, peak heights and durations as amperometric spikes elicited by depolarizing high K(+) solutions, therefore release occurs from individual secretory granules. Uptake of trypan blue stain into cells demonstrated that the plasma membrane is permeabilized by the voltage stimulus. Voltage pulses did not degrade the electrochemical sensitivity of the electrodes assayed using a test analyte. Surprisingly, robust quantal release was elicited upon electroporation in the absence of Ca(2+) in the bath solution (0 Ca(2+)/5 mM EGTA). In contrast, electropermeabilization-induced transmitter release required Cl(-) in the bath solution in that bracketed experiments demonstrated a steep dependence of the rate of electropermeabilization-induced transmitter release on [Cl(-)] between 2 and 32 mM. Using the same electrochemical electrode to electroporate and record quantal release of catecholamines from an individual chromaffin cell allows precise timing of the stimulus, stimulation of a single cell at a time, and can be used to load membrane-impermeant substances into a cell. PMID:23598689

Ghosh, Jaya; Liu, Xin; Gillis, Kevin D

2013-06-01

226

Nanoarchitectured electrochemical cytosensors for selective detection of leukemia cells and quantitative evaluation of death receptor expression on cell surfaces.  

PubMed

The variable susceptibility to the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment observed in various types of leukemia cells is related to the difference in the expression levels of death receptors, DR4 and DR5, on the cell surfaces. Quantifying the DR4/DR5 expression status on leukemia cell surfaces is of vital importance to the development of diagnostic tools to guide death receptor-based leukemia treatment. Taking the full advantages of novel nanobiotechnology, we have developed a robust electrochemical cytosensing approach toward ultrasensitive detection of leukemia cells with detection limit as low as ~40 cells and quantitative evaluation of DR4/DR5 expression on leukemia cell surfaces. The optimization of electron transfer and cell capture processes at specifically tailored nanobiointerfaces and the incorporation of multiple functions into rationally designed nanoprobes provide unique opportunities of integrating high specificity and signal amplification on one electrochemical cytosensor. The high sensitivity and selectivity of this electrochemical cytosensing approach also allows us to evaluate the dynamic alteration of DR4/DR5 expression on the surfaces of living cells in response to drug treatments. Using the TRAIL-resistant HL-60 cells and TRAIL-sensitive Jurkat cells as model cells, we have further verified that the TRAIL susceptibility of various types of leukemia cells is directly correlated to the surface expression levels of DR4/DR5. This versatile electrochemical cytosensing platform is believed to be of great clinical value for the early diagnosis of human leukemia and the evaluation of therapeutic effects on leukemia patients after radiation therapy or drug treatment. PMID:23621478

Zheng, Tingting; Fu, Jia-Ju; Hu, Lihui; Qiu, Fan; Hu, Minjin; Zhu, Jun-Jie; Hua, Zi-Chun; Wang, Hui

2013-05-14

227

Electrochemical cell-based chip for the detection of toxic effects of bisphenol-A on neuroblastoma cells  

Microsoft Academic Search

A cell-based chip was fabricated for the electrochemical detection of the dose-dependent effects of bisphenol-A (BPA) on neuroblastoma cells (SH-SY5Y), which showed dual-mode correlation as a standard curve. Toxicity assessment of BPA became very important in environmental toxicants detection since BPA can be reached out easily from various common plastic-based product and give negative cellular effects on living organism. Cell

Tae-Hyung Kim; Jeung Hee An; Jeong-Woo Choi

2011-01-01

228

Interfacial phenomena observed in electrochemical systems (lithium-ion batteries, fuel cells, dye sensitized solar cells); causes, relevance and enhancements  

NASA Astrophysics Data System (ADS)

This dissertation is aimed to understand the interfacial phenomena in electrochemical systems. Three electrochemical systems, namely, Lithium Ion Batteries, Fuel Cells and Dye Sensitized Solar Cells were chosen to elucidate the different type of the interfaces involved. In Lithium ion batteries the interface between an electrode and an electrolyte called as the solid electrolyte interface plays an important role in the electrochemical performance. Solid electrolyte interface also has a direct correlation with thermal runaway which causes such systems to explode. An in-depth analysis of this interface has been explored using techniques such as differential scanning calorimeter (DSC), accelerating rate calorimeter (ARC) as well as material characterization by X-ray diffraction (XRD) and Transmission Electron Microscope (TEM). Electrochemical Impedance spectroscopy has also been used extensively in conjunction with the techniques mentioned above. In Fuel Cells, novel spiral flow channels have been proposed. The objective of these flow channels is to increase the effective reactant distribution to the surface of the catalyst and effectively remove water being formed as the reactant products at the catalyst interface. With respect to fuel cells, most of the work is towards catering to the interface rather that dealing directly with the interfacial phenomena (catalyst, membranes). In-situ neutron scattering were conducted to visualize the water formation and draining mechanism in the proposed spiral flow channels. In Dye Sensitized solar cells, the interface plays an important role in terms of the performance over a long period of time. Preliminary investigation has been carried out using electrochemical impedance spectroscopy (EIS) and the different regions within an operating cell have been identified.

Amiruddin, Shabab

229

Reflection-mode x-ray powder diffraction cell for in situ studies of electrochemical reactions  

NASA Astrophysics Data System (ADS)

The design and operation of an electrochemical cell for reflection-mode powder x-ray diffraction experiments are discussed. The cell is designed for the study of electrodes that are used in rechargeable lithium batteries. It is designed for assembly in a glove box so that air-sensitive materials, such as lithium foil electrodes and carbonate-based electrolytes with lithium salts, can be used. The cell uses a beryllium window for x-ray transmission and electrical contact. A simple mechanism for compressing the electrodes is included in the design. Sample results for the cell are shown with a Cu K? source and a position-sensitive detector.

Roberts, G. A.; Stewart, K. D.

2004-05-01

230

Electrochemical cell apparatus having axially distributed entry of a fuel-spent fuel mixture transverse to the cell lengths  

DOEpatents

An electrochemical apparatus is made having a generator section containing axially elongated electrochemical cells, a fresh gaseous feed fuel inlet, a gaseous feed oxidant inlet, and at least one gaseous spent fuel exit channel, where the spent fuel exit channel passes from the generator chamber to combine with the fresh feed fuel inlet at a mixing apparatus, reformable fuel mixture channel passes through the length of the generator chamber and connects with the mixing apparatus, that channel containing entry ports within the generator chamber, where the axis of the ports is transverse to the fuel electrode surfaces, where a catalytic reforming material is distributed near the reformable fuel mixture entry ports. 2 figures.

Reichner, P.; Dollard, W.J.

1991-01-08

231

Microfluidic electrochemical reactors  

SciTech Connect

A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

Nuzzo, Ralph G. (Champaign, IL); Mitrovski, Svetlana M. (Urbana, IL)

2011-03-22

232

Electrochemical Performance and Stability of the Cathode for Solid Oxide Fuel Cells: III. Role of volatile boron species on LSM/YSZ and LSCF  

SciTech Connect

Boron oxide is a key component to tailor the softening temperature and viscosity of the sealing glass for solid oxide fuel cells. The primary concern regarding the use of boron containing sealing glasses is the volatility of boron species, which possibly results in cathode degradation. In this paper, we report the role of volatile boron species on the electrochemical performance of LSM/YSZ and LSCF cathodes at various SOFC operation temperatures. The transport rate of boron, ~ 3.24×10-12 g/cm2•sec was measured at 750°C with air saturated with 2.8% moisture. A reduction in power density was observed in cells with LSM/YSZ cathodes after introduction of the boron source to the cathode air stream. Partial recovery of the power density was observed after the boron source was removed. Results from post-test secondary ion mass spectroscopy (SIMS) analysis the partial recovery in power density correlated with partil removal of the deposited boron by the clean air stream. The presence of boron was also observed in LSCF cathodes by SIMS analysis, however the effect of boron on the electrochemical performance of LSCF cathode was negligible. Coverage of triple phase boundaries in LSM/YSZ was postulated as the cause for the observed reduction in electrochemical performance.

Zhou, Xiao Dong; Templeton, Jared W.; Zhu, Zihua; Chou, Y. S.; Maupin, Gary D.; Lu, Zigui; Brow, R. K.; Stevenson, Jeffry W.

2010-09-02

233

Electrochemical Oscillations of Nickel Electrodissolution in an Epoxy-Based Microchip Flow Cell  

PubMed Central

We investigate the nonlinear dynamics of transpassive electrodissolution of nickel in sulfuric acid in an epoxy-based microchip flow cell. We observed bistability, smooth, relaxation, and period-2 waveform current oscillations with external resistance attached to the electrode in the microfabricated electrochemical cell with 0.05 mm diameter Ni wire under potentiostatic control. Experiments with 1mm × 0.1 mm Ni electrode show spontaneous oscillations without attached external resistance; similar surface area electrode in macrocell does not exhibit spontaneous oscillations. Combined experimental and numerical studies show that spontaneous oscillation with the on-chip fabricated electrochemical cell occurs because of the unusually large ohmic potential drop due to the constrained current in the narrow flow channel. This large IR potential drop is expected to have an important role in destabilizing negative differential resistance electrochemical (e.g., metal dissolution and electrocatalytic) systems in on-chip integrated microfludic flow cells. The proposed experimental setup can be extendend to multi-electrode configurations; the epoxy-based substrate procedure thus holds promise in electroanalytical applications that require collector-generator multi-electrodes wires with various electrode sizes, compositions, and spacings as well as controlled flow conditions.

Cioffi, Alexander G.; Martin, R. Scott; Kiss, Istvan Z.

2011-01-01

234

Exploratory cell research and fundamental processes study in solid state electrochemical cells  

SciTech Connect

Last year this program demonstrated that alternative to lithium had some merit on which to base new polymer electrolyte batteries and other electrochemical devices. We reported that Na, Zn, and Cu electrolytes have modest conductivities at 100{degree}C. Some preliminary cell cycling data were reported with V{sub 6}O{sub 13} insertion cathodes, and the successful cell cycling suggested that N{sup +}, Zn{sup +2} could be inserted and removed reversibly in the cathode material. Also, thin-film polymer cathodes were shown by impedance measurements to have three characteristic regions of behavior. Each region had different controlling processes with relaxation time constants that could be separated with careful manipulation of film thickness, morphology, and charging level. The present report gives results of the continuation of these studies. In particular, the sodium system was studied more intensively with conductivity measurements on sodium triflate in poly(ethyleneoxide)(PEO), and cell studies with V{sub 6}O{sub 13} and poly(pyrrole)(PPY) cathodes. The impedance work was concluded and several directions of new work in that area were identified. The insertion studies with single crystal V{sub 6}O{sub 13} were concluded on this program and transferred to NSF funding. 29 refs., 6 figs., 6 tabs.

Smyrl, W.H.; Owens, B.B.; White, H.S. (Minnesota Univ., Minneapolis, MN (USA). Dept. of Chemical Engineering and Materials Science)

1990-06-01

235

Characterization of PEM fuel cell membrane-electrode-assemblies by electrochemical methods and microanalysis  

SciTech Connect

Characterization of Membrane Electrode Assemblies (MEAs) is used to help optimize construction of the MEA. Characterization techniques include electron microscopies (SEM and TEM), and electrochemical evaluation of the catalyst. Electrochemical hydrogen adsorption/desorption (HAD) and CO oxidation are used to evaluate the active Pt surface area of fuel cell membrane electrode assemblies. Electrochemical surface area measurements have observed large active Pt surface areas, on the order of 50 m{sup 2}/g for 20% weight Pt supported on graphite. Comparison of the hydrogen adsorption/desorption with CO oxidation indicates that on the supported catalysts, the saturation coverage of CO/Pt is about 0.90, the same as observed in H{sub 2}SO{sub 4}. The catalyst surface area measurements are nearly a factor of 2 lower than the Pt surface area calculated from the 30 {angstrom} average particle size observed by TEM. The electrochemical measurements combined with microanalysis of membrane electrode assemblies, allow a greater understanding and optimization of process variables.

Borup, R.L.; Vanderborgh, N.E.

1995-09-01

236

Cellulose synthesis in two secondary cell wall processes in a single cell type  

PubMed Central

Plant cells have a rigid cell wall that constrains internal turgor pressure yet extends in a regulated and organized manner to allow the cell to acquire shape. The primary load-bearing macromolecule of a plant cell wall is cellulose, which forms crystalline microfibrils that are organized with respect to a cell's function and shape requirements. A primary cell wall is deposited during expansion whereas secondary cell wall is synthesized post expansion during differentiation. A complex form of asymmetrical cellular differentiation occurs in Arabidopsis seed coat epidermal cells, where we have recently shown that two secondary cell wall processes occur that utilize different cellulose synthase (CESA) proteins. One process is to produce pectinaceous mucilage that expands upon hydration and the other is a radial wall thickening that reinforced the epidermal cell structure. Our data illustrate polarized specialization of CESA5 in facilitating mucilage attachment to the parent seed and CESA2, CESA5 and CESA9 in radial cell wall thickening and formation of the columella. Herein, we present a model for the complexity of cellulose biosynthesis in this highly differentiated cell type with further evidence supporting each cellulosic secondary cell wall process.

Mendu, Venugopal; Stork, Jozsef; Harris, Darby; DeBolt, Seth

2011-01-01

237

Yellow-green light-emitting electrochemical cells with long lifetime and high efficiency  

NASA Astrophysics Data System (ADS)

We show that the electrochemical stability window of the constituent components in light-emitting electrochemical cells (LECs), e.g., the electrolyte, should be considered in order to minimize undesired side reactions. By designing and operating LECs in accordance with straightforward principles, we demonstrate sandwich cells that turn on fast at room temperature (<2 s), and which emit significant yellow-green light (>100 cd/m2) during 25 days of uninterrupted operation at low voltage (<4 V) and high power conversion efficacy (~6 lm/W). We further demonstrate that it is possible to attain balanced p- and n-type doping and a centered p-n junction in such planar LECs based on the conjugated polymer ``superyellow.''

Sandström, Andreas; Matyba, Piotr; Edman, Ludvig

2010-02-01

238

Electrochemical cell for facilitating hermeticity leakage testing of an electrical feedthrough  

SciTech Connect

An electrical feedthrough, including a metal ferrule, an electrical lead, a glass seal for centrally locating the electrical lead axially within ferrule, for electrically isolating the electrical lead from the ferrule and for hermetically sealing the feedthrough assembly, which further includes an injection molded insulating material extending between the ferrule and lead and a fluorocarbon washer positioned adjacent the inner surface of the glass seal. The fluorocarbon washer is capable of retaining helium and allows for the hermeticity leakage testing of the glass seal. Such a feedthrough is particularly useful in hermetically sealed electrochemical cells wherein the insulated portion of the feedthrough is placed in the cell and the uninsulated portion of the ferrule is welded to or forms the cell cover, and the electrical lead is electrically connected to cell components, such as the anode, within the cell. The hermeticity testing of the aforementioned cell is accomplished by constructing the electrical feedthrough with the teflon washer in position; attaching the feedthrough to the hermetically sealed cells; placing the completed electrochemical cell in a pressurized atmosphere of a test gas, such as helium, for a period of time to force the test gas through the glass seal into the chamber containing the fluorocarbon washer, whereby the fluorocarbon washer absorbs helium gas; and examining the electrochemical cell for leakage of any of the helium back out through the glass seal. Gross and fine leakage testing may be accomplished by respectively observing the escape of the test gas at atmospheric pressure and drawing a vacuum on the electrical feedthrough and testing for the escape of the test gas with a mass spectrometer.

Jurva, E.O.; Goodin, R.L.

1984-07-17

239

Simultaneous organics removal and bio-electrochemical denitrification in microbial fuel cells  

Microsoft Academic Search

Simultaneous organics removal and bio-electrochemical denitrification using a microbial fuel cell (MFC) reactor were investigated\\u000a in this study. The electrons produced as a result of the microbial oxidation of glucose in the anodic chamber were transferred\\u000a to the anode, which then flowed to the cathode in the cathodic chamber through a wire, where microorganisms used the transferred\\u000a electrons to reduce

Yu-Hong Jia; Hung-Thuan Tran; Dae-Hee Kim; Se-Jin Oh; Doo-Hyun Park; Rui-Hong Zhang; Dae-Hee Ahn

2008-01-01

240

Polymer Light-Emitting Electrochemical Cells for High-Efficiency Low-Voltage Electroluminescent Devices  

Microsoft Academic Search

Organic light-emitting devices exhibiting high power conversion efficiency and long operating lifetime may potentially be achieved with the polymer light-emitting electrochemical cell (LEC) configuration. An LEC device typically uses a thin layer of conjugated polymer sandwiched between two contact electrodes. The polymer layer contains an ionically conductive species that are essential in the formation of a light-emitting p-i-n junction. LEC

Qingjiang Sun; Yongfang Li; Qibing Pei

2007-01-01

241

Design and application of a flow cell for carbon-film based electrochemical enzyme biosensors  

Microsoft Academic Search

A flow cell has been designed for use with an electrochemical enzyme biosensor, based on low-cost carbon-film electrodes. Three types of mediators were used: cobalt and copper hexacyanoferrates and poly(neutral red) (PNR), covered with glucose oxidase (GOx) immobilised by cross-linking with glutaraldehyde in the presence of bovine serum albumin or inside a oxysilane sol–gel network. Mixtures of sol–gel precursors were

Madalina M. Barsan; Janja Klin?ar; Martin Bati?; Christopher M. A. Brett

2007-01-01

242

Evolution of absorption spectra of C60 film in solid electrolyte cell during electrochemical reduction  

Microsoft Academic Search

Absorption spectra of C60 film reduced electrochemically in a cell composed of solid polymer electrolyte and LiClO4 are studied. The results are compared with data of C60 anion solutions and films doped with alkali metals by vapor phase. Little difference is found in absorption spectra between the solutions and films of reduced C60 up to di-anion at least. This fact

K. Kaneto; T. Abe; W. Takashima

1995-01-01

243

Fabrication and electrochemical performance of solid oxide fuel cell components by atmospheric and suspension plasma spray  

Microsoft Academic Search

The theory of functionally graded material (FGM) was applied in the fabrication process of PEN (Positive-Electrolyte-Negative), the core component of solid oxide fuel cell (SOFC). To enhance its electrochemical performance, the functionally graded PEN of planar SOFC was prepared by atmospheric plasma spray (APS). The cross-sectional SEM micrograph and element energy spectrum of the resultant PEN were analyzed. Its interface

Wei-sheng XIA; Yun-zhen YANG; Hai-ou ZHANG; Gui-lan WANG

2009-01-01

244

Electrochemical solar cells based on layer-type transition metal compounds - Performance of electrode material  

Microsoft Academic Search

The effect of doping of MoSe2 (band gap 1.4 eV) as well as the influence of the electrochemical potential of the redox-couple in the electrolyte have been investigated in an effort to optimize solar cells based on layer compounds. It is shown that in the case of I(-)\\/I2 the mechanism of photopotential generation is assisted by a favorable chemical modification

H. Tributsch

1979-01-01

245

Preparation and electrochemical characteristics of a new rechargeable Li\\/PAn[FeOCl(an)] cell  

Microsoft Academic Search

To increase the rechargeability and energy density, polyaniline(PAn)\\/FeOCl(an) composite cathode was made newly. The electrochemical characteristics of its lithium cells at 30°C were investigated by using cyclic voltammetry, a.c. impedance method, and other techniques. Especially, the reducing and enhancement effects of the resistance at electrolyte\\/cathode interface and the energy density by using the conducting polyaniline thin film could be plausibly

K. S. Hwang; J. S. Kim; M. J. Kong

1995-01-01

246

Effect of plasticizer on safranine-T-dye-based solid-state photo electrochemical cell  

Microsoft Academic Search

Effect of plasticizers on electrical and photovoltaic properties of safranine-T-dye-based solid-state photo electrochemical\\u000a cell (PEC) is studied. Ethylene carbonate (EC) and propylene carbonate (PC) are used as plasticizers. Dark current–voltage\\u000a characteristic and different photovoltaic parameters such as open-circuit voltage, short-circuit current, and power conversion\\u000a efficiency are measured. To understand the effect of plasticizers on charge transport process, we analyze the

S. Maity; A. Haldar; N. B. Manik

2008-01-01

247

A new contactless electrochemical etch-stop based on a gold\\/silicon\\/TMAH galvanic cell  

Microsoft Academic Search

Fabrication of micromechanical structures with a reproducible thickness is usually accomplished by electrochemically controlled etching. This method requires an external contact to the n-type silicon to be passivated. The contact is usually accomplished by a wafer holder, which may introduce stress into the wafer and complicate batch fabrication. A new technique based on a gold\\/silicon\\/TMAH galvanic cell is presented. The

C. M. A. Ashruf; P. J. French; P. M. M. C. Bressers; P. M. Sarro; J. J. Kelly

1998-01-01

248

Study of electrochemical processes and wetting phenomena at the molten carbonate fuel cell anode  

NASA Astrophysics Data System (ADS)

A study to ellucidate the mechanism and kinetics of the hydrogen oxidation reaction in various molten carbonate compositions and at different candidate electrode materials is presented. Experimental conditions and electrochemical methods were investigated in order to obtain more basic knowledge of the molten carbonate anode system. The described experiments have a strongly exploratory character, and most of the experiments were conducted at gold electrodes. A critical analysis of the possibilities offered by four electrochemical techniques for the elucidation of the hydrogen oxidation reaction is given. To facilitate the elucidation of the hydrogen oxidation mechanism, the experimental problems accompanying research in molten carbonates are described along with possible solutions. In order to make up arrears regarding fundamental aspects of the anodic fuel cell reaction, an extensive discussion on molten carbonate chemistry, proposed mechanisms, electrochemical techniques, and porous electrodes is given. Experiments performed at solid electrodes on the so called 'pot cell' or 'half cell', comprising polarization measurements, cyclic voltammetry, chrono-amperometry, and impedance measurements at gold, nickel, and copper flag electrodes in Li/K carbonate, are described. Impedance measurements carried out at aporous Ni/Cr anode in a symmetric laboratory are described. Wetting experiments carried out using the sessile drop method are described.

Weewer, Ricardo

249

Materials for electrochemical energy storage and conversion -- Batteries, capacitors and fuel cells  

SciTech Connect

The papers contained in this volume were presented at Symposium W: Materials for Electrochemical Energy Storage and Conversion -- Batteries, Capacitors and Fuel Cells, that was held during the 1995 MRS Spring Meeting in San Francisco, California, April 17--20, 1995. The symposium was organized as a forum for uniting materials scientists with electrochemists and battery engineers, with the hope of increasing communication and understanding of electrochemical aspects of materials. It is believed that the development of high-performance power sources for applications ranging from portable electronics to electric and hybrid vehicles is intimately linked with availability of advanced materials. Designing batteries and capacitors with higher specific energy and power will require a deeper understanding of materials properties and performance. Fuel cells, which offer the potential for clean, efficient conversion of chemical energy to electrical energy, are hampered by high cost and performance problems, both of which could be resolved by new materials and processing techniques. Sessions were organized on oxides, hydrides, polymers and carbons as they relate to fuel cells, batteries and electrochemical double-layer capacitors. Moreover, reviews of the current status of materials performance and needs were presented in each of the application areas. Forty nine papers have been processed separately for inclusion on the data base.

Doughty, D.H. [ed.] [Sandia National Labs., Albuquerque, NM (United States); Vyas, B. [ed.] [AT and T Bell Labs., Murray Hill, NJ (United States); Takamura, Tsutomu [ed.] [Rikkyo Univ., Tokyo (Japan); Huff, J.R. [ed.] [Ballard Power Corp., Albuquerque, NM (United States)

1995-12-31

250

Electrochemical biosensors for on-chip detection of oxidative stress from immune cells.  

PubMed

Seamless integration of biological components with electrochemical sensors is critical in the development of microdevices for cell analysis. The present paper describes the integration miniature Au electrodes next to immune cells (macrophages) in order to detect cell-secreted hydrogen peroxide (H(2)O(2)). Photopatterning of poly(ethylene glycol) (PEG) hydrogels was used to both immobilize horseradish peroxidase molecules onto electrodes and to define regions for cell attachment in the vicinity of sensing electrodes. Electrodes micropatterned in such a manner were enclosed inside poly(dimethylsiloxane) fluid conduits and incubated with macrophages. The cells attached onto the exposed glass regions in the vicinity of the electrodes and nowhere else on the non-fouling PEG hydrogel surface. A microfluidic device was converted into an electrochemical cell by placing flow-through Ag?AgCl reference and Pt wire counter electrodes at the outlet and inlet, respectively. This microdevice with integrated H(2)O(2)-sensing electrodes had sensitivity of 27 ?A?cm(2) mM with a limit of detection of 2 ?M. Importantly, this microdevice allowed controllable seeding of macrophages next to electrodes, activation of these cells and on-chip monitoring of H(2)O(2) release in real time. In the future, this biosensor platform may be utilized for monitoring of macrophage responses to pathogens or for the study of inflammatory signaling in micropatterned cell cultures. PMID:22007269

Yan, Jun; Pedrosa, Valber A; Enomoto, James; Simonian, Aleksandr L; Revzin, Alexander

2011-09-20

251

Electronic circuit for measuring series connected electrochemical cell voltages  

DOEpatents

An electronic circuit for measuring voltage signals in an energy storage device is disclosed. The electronic circuit includes a plurality of energy storage cells forming the energy storage device. A voltage divider circuit is connected to at least one of the energy storage cells. A current regulating circuit is provided for regulating the current through the voltage divider circuit. A voltage measurement node is associated with the voltage divider circuit for producing a voltage signal which is proportional to the voltage across the energy storage cell.

Ashtiani, Cyrus N. (West Bloomfield, MI); Stuart, Thomas A. (Toledo, OH)

2000-01-01

252

Metabolic and Electrochemical Mechanisms of Dimeric Naphthoquinones Cytotoxicity in Breast Cancer Cells  

PubMed Central

Cancer cells reprogram their metabolism due to genetic alteration to compensate for increased energy demand and enhanced anabolism, cell proliferation, and protection from oxidative damage. Here, we assessed the cytotoxicity of three dimeric naphthoquinones against the glycolytic MCF-7 versus the oxidative MDA-453 breast carcinoma cell lines. Dimeric naphthoquinones 1 and 2 impaired MDA-453, but not MCF-7, cell growth at IC50 = 15 ?M. Significant increase in reactive oxygen species, decrease in oxygen consumption and ATP production were observed in MDA-453 cells but not in MCF-7 cell. These findings suggest that oxidative stress and mitochondrial dysfunction are mechanisms by which these agents exert their cytotoxic effects. Cyclic voltammetry and semi-empirical molecular orbital calculations further characterized the electrochemical behavior of these compounds. These results also suggest that dimeric naphthoquinones may be used to selectively target cancer cells that depend on oxidative phosphorylation for energy production and macromolecular synthesis.

Emadi, Ashkan; Le, Anne; Harwood, Cynthia J.; Stagliano, Kenneth W.; Kamangar, Farin; Ross, Ashley E.; Cooper, Charles R.; Dang, Chi V.; Karp, Judith E.; Vuica-Ross, Milena

2011-01-01

253

Cell-adhesive and cell-repulsive zwitterionic oligopeptides for micropatterning and rapid electrochemical detachment of cells.  

PubMed

In this study, we describe the development of oligopeptide-modified cell culture surfaces from which adherent cells can be rapidly detached by application of an electrical stimulus. An oligopeptide, CGGGKEKEKEK, was designed with a terminal cysteine residue to mediate binding to a gold surface via a gold-thiolate bond. The peptide forms a self-assembled monolayer through the electrostatic force between the sequence of alternating charged glutamic acid (E) and lysine (K) residues. The dense and electrically neutral oligopeptide zwitterionic layer of the modified surface was resistant to nonspecific adsorption of proteins and adhesion of cells, while the surface was altered to cell adhesive by the addition of a second oligopeptide (CGGGKEKEKEKGRGDSP) containing the RGD cell adhesion motif. Application of a negative electrical potential to this gold surface cleaved the gold-thiolate bond, leading to desorption of the oligopeptide layer, and rapid (within 2?min) detachment of virtually all cells. This approach was applicable not only to detachment of cell sheets but also for transfer of cell micropatterns to a hydrogel. This electrochemical approach of cell detachment may be a useful tool for tissue-engineering applications. PMID:22853640

Kakegawa, Takahiro; Mochizuki, Naoto; Sadr, Nasser; Suzuki, Hiroaki; Fukuda, Junji

2012-09-05

254

An electrochemical cell for the Faraday constant determination  

Microsoft Academic Search

A new 2-electrode cell for the electro-gravimetric determination of silver has been designed and is now under test. The new set-up allows accurate galvanostatic measurements of the dissolution of the Ag electrode with a strict control on the Ag+ ion concentration in the two sides of the cell solution. The solution stability, the residue recovery, the O2 prevention and the

F. Durbiano; U. Pogliano; D. Serazio

2008-01-01

255

Assessment of multidrug resistance on cell coculture patterns using scanning electrochemical microscopy  

PubMed Central

The emergence of resistance to multiple unrelated chemotherapeutic drugs impedes the treatment of several cancers. Although the involvement of ATP-binding cassette transporters has long been known, there is no in situ method capable of tracking this transporter-related resistance at the single-cell level without interfering with the cell’s environment or metabolism. Here, we demonstrate that scanning electrochemical microscopy (SECM) can quantitatively and noninvasively track multidrug resistance-related protein 1–dependent multidrug resistance in patterned adenocarcinoma cervical cancer cells. Nonresistant human cancer cells and their multidrug resistant variants are arranged in a side-by-side format using a stencil-based patterning scheme, allowing for precise positioning of target cells underneath the SECM sensor. SECM measurements of the patterned cells, performed with ferrocenemethanol and [Ru(NH3)6]3+ serving as electrochemical indicators, are used to establish a kinetic “map” of constant-height SECM scans, free of topography contributions. The concept underlying the work described herein may help evaluate the effectiveness of treatment administration strategies targeting reduced drug efflux.

Kuss, Sabine; Polcari, David; Geissler, Matthias; Brassard, Daniel; Mauzeroll, Janine

2013-01-01

256

Sensitive detection of CD147/EMMPRIN and its expression on cancer cells with electrochemical technique.  

PubMed

Cluster of differentiation 147 (CD147), also known as extracellular matrix metalloproteinase inducer (EMMPRIN), plays an essential role in tumor progression and metastasis, the expression of which on cell surface is a critical clinical testing index for cancer therapy. In this work, an electrochemical method to assay CD147/EMMPRIN expression on tumor cell surface is proposed. While the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) catalyzed by horseradish peroxidase (HRP) can be employed for electrochemical measurement, the signal enhancement amplified by gold nanoparticles (GNPs) can be also utilized in this study. Therefore, under optimized conditions, the fabricated biosensor responds linearly to the CD147/EMMPRIN concentration from 125 to 1000 pg/mL with a detection limit as low as 52 pg/mL. High sensitivity can also be achieved for the quantification of breast cancer cells in a linear range from 6.2 × 10(4) to 6.25 × 10(5) cells/mL. Moreover, the CD147/EMMPRIN expressed on a single breast cancer cell can be calculated as 2.57 × 10(4) molecules/cell. The proposed strategy in this study is considerably potential for monitoring the dynamic protein expression on cancer cells and for the effective cancer diagnosis and treatment in the future. PMID:23598007

Zheng, Dianyuan; Zhu, Xuejun; Ding, Xiaorong; Zhu, Xiaoli; Yin, Yongmei; Li, Genxi

2012-12-03

257

Secondary cytokine production by lymphoid cells used in cellular immunotherapy.  

PubMed

Interleukin-2 (IL-2) has been used extensively in cellular immunotherapy trials as a systemic activator of the immune system as well as an ex vivo stimulant for lymphoid cell function. Despite the measurement of several in vitro and in vivo immunologic parameters related to cellular immunotherapy, determinants of successful cellular immunotherapy remain unknown. To further delineate the consequences of exposing peripheral blood lymphocytes to high concentrations of IL-2, we assessed the supernatants of IL-2-activated peripheral blood lymphocytes for production of tumour necrosis factor (TNF) and interferon-gamma (IFN-gamma). Exposure of normal monocyte-depleted peripheral blood mononuclear cells (PBMC) to IL-2 caused a dose-dependent increase in secretion of TNF and IFN-gamma which increased linearly after 48 h in culture. Analysis of positively selected, highly purified PBMC subpopulations exposed to IL-2 revealed that TNF-alpha and TNF-beta were produced by both CD3+ and CD16+ subpopulations but not by CD22+ cells. These studies were extended to supernatants obtained from PBMC cultures used in the adoptive cellular immunotherapy of patients with advanced cancer. Patients treated with lymphokine-activated killer (LAK) cell immunotherapy were classified as responders (N = 14) or non-responders (N = 17) to therapy. We found no significant difference in the production of TNF between responders and nonresponders (22 +/- 9 U ml-1 vs. 20 +/- 6 U ml-1), P > 0.05. However, LAK cell supernatants harvested from non-responders contained a significantly higher level of IFN-gamma (232 +/- 94 U ml-1) compared with responders (42 +/- 14), P < 0.05. Furthermore, the linear association between IFN-gamma and TNF-alpha production was different between these two response groups (rs = -0.19 for non-responders and rs = 0.48 for responders). These results suggest that secondary cytokine production by adoptively transferred lymphocytesmay play an important role in the host response to cellular immunotherapy. PMID:1341247

Schoof, D D; Hunt, P; Obando, J A; Cusack, J C; Andrews, V; Terashima, Y; Eberlein, T J

1992-04-01

258

Electrochemical and surface science research on fuel cells  

NASA Astrophysics Data System (ADS)

The development of advanced acid electrolyte fuel cells for power generation and transportation application is investigated. The ions CF3SO3(-) and H2PO4(-) have similar adsorption characteristics on mercury from dilute aqueous electrolytes ( 1 M). Transport properties in phosphoric acid show strong temperature and concentration dependences. Solvent clusters account for transport of 6 to 9 moles of water per mole of proton through Nafion membranes. Exchange current densities for oxygen reduction on platinum are dependent on anion adsorption from the electrolyte. The nuclear microprobe technique reveal: (1) the three-dimensional distribution of platinum in a fuel cell electrode, and (2) the loss of vanadium from a Pt-V electrocatalyst during fuel cell operation. The ellipsometric method was developed to measure anion adsorption on platinum. Single cells were assembled and tested for the proposed simulated drive-cycle-performance evaluations. An energy balance was made for a 20 kW phosphoric acid fuel cell power plant for a GM X-car.

Srinivasan, S.; Gonzalez, E. R.; Hsueh, K. L.; Chin, D. T.; Hyde, P. J.; Maggiore, C. J.; Gottesfeld, S.; Chang, H. R.; Derouin, C. R.; Bobbett, R. E.

1984-06-01

259

Improved conversion rates in drug screening applications using miniaturized electrochemical cells with frit channels.  

PubMed

This paper reports a novel design of a miniaturized three-electrode electrochemical cell, the purpose of which is aimed at generating drug metabolites with a high conversion efficiency. The working electrode and the counter electrode are placed in two separate channels to isolate the reaction products generated at both electrodes. The novel design includes connecting channels between these two electrode channels to provide a uniform distribution of the current density over the entire working electrode. In addition, the effect of ohmic drop is decreased. Moreover, two flow resistors are included to ensure an equal flow of analyte through both electrode channels. Total conversion of fast reacting ions is achieved at flow rates up to at least 8 ?L/min, while the internal chip volume is only 175 nL. Using this electrochemical chip, the metabolism of mitoxantrone is studied by microchip electrospray ionization-mass spectrometry. At an oxidation potential of 700 mV, all known metabolites from direct oxidation are observed. The electrochemical chip performs equally well, compared to a commercially available cell, but at a 30-fold lower flow of reagents. PMID:23020795

Odijk, Mathieu; Olthuis, Wouter; van den Berg, A; Qiao, Liang; Girault, Hubert

2012-10-22

260

Microfabrication of a digital microfluidic platform integrated with an on-chip electrochemical cell  

NASA Astrophysics Data System (ADS)

We report on an IC compatible microfabrication process proposed for a novel monolithic lab-on-a-chip (LOC) with an electrochemical cell embedded in an electrowetting on dielectric (EWOD) digital microfluidic device. The optimized process focused on the surface modification of Teflon, selective exposure for the electrochemical module and recovery of surface properties by one-step annealing at low temperature. The optimum modification time and annealing temperature were 20 s and 210 °C, respectively. The experimental results from atomic force microscope and contact angle (CA) measurement revealed the effects of surface roughness and apparent CA on the wettability for different etch times. The multifunctionality of droplet creation, merger and transportation in the EWOD microfluidic module and sensitive electrochemical detection for the redox probe were realized simultaneously. The proposed microfabrication process has many advantages of remarkable simplicity, prominent repeatability, low cost and compatibility with standard IC processes. It shows great promise for the microsystem of the microfluidic unit and detecting cell, and gives a brilliant conception for the future fabrication of monolithic LOC integrated with functional detection.

Yu, Yuhua; Chen, Jianfeng; Li, Jian; Yang, Sheng; Fan, Shih-Kang; Zhou, Jia

2013-09-01

261

Fabrication of VB2/Air Cells for Electrochemical Testing.  

PubMed

A technique to investigate the properties and performance of new multi-electron metal/air battery systems is proposed and presented. A method for synthesizing nanoscopic VB2 is presented as well as step-by-step procedure for applying a zirconium oxide coating to the VB2 particles for stabilization upon discharge. The process for disassembling existing zinc/air cells is shown, in addition construction of the new working electrode to replace the conventional zinc/air cell anode with a the nanoscopic VB2 anode. Finally, discharge of the completed VB2/air battery is reported. We show that using the zinc/air cell as a test bed is useful to provide a consistent configuration to study the performance of the high-energy high capacity nanoscopic VB2 anode. PMID:23962835

Stuart, Jessica; Lopez, Ruben; Lau, Jason; Li, Xuguang; Waje, Mahesh; Mullings, Matthew; Rhodes, Christopher; Licht, Stuart

2013-08-05

262

Process for manufacturing a lithium alloy electrochemical cell  

DOEpatents

A process for manufacturing a lithium alloy, metal sulfide cell tape casts slurried alloy powders in an organic solvent containing a dissolved thermoplastic organic binder onto casting surfaces. The organic solvent is then evaporated to produce a flexible tape removable adhering to the casting surface. The tape is densified to increase its green strength and then peeled from the casting surface. The tape is laminated with a separator containing a lithium salt electrolyte and a metal sulfide electrode to form a green cell. The binder is evaporated from the green cell at a temperature lower than the melting temperature of the lithium salt electrolyte. Lithium alloy, metal sulfide and separator powders may be tape cast.

Bennett, William R. (North Olmstead, OH)

1992-10-13

263

Low-hazard metallography of moisture-sensitive electrochemical cells.  

PubMed

A low-hazard approach is presented to prepare metallographic cross-sections of moisture-sensitive battery components. The approach is tailored for evaluation of thermal (molten salt) batteries composed of thin pressed-powder pellets, but has general applicability to other battery electrochemistries. Solution-cast polystyrene is used to encapsulate cells before embedding in epoxy. Nonaqueous grinding and polishing are performed in an industrial dry room to increase throughput. Lapping oil is used as a lubricant throughout grinding. Hexane is used as the solvent throughout processing; occupational exposure levels are well below the limits. Light optical and scanning electron microscopy on cross-sections are used to analyse a thermal battery cell. Spatially resolved X-ray diffraction on oblique angle cut cells complement the metallographic analysis. PMID:21477264

Wesolowski, D E; Rodriguez, M A; McKenzie, B B; Papenguth, H W

2011-04-11

264

Electrochemically grown ZnO nanorods for hybrid solar cell applications  

SciTech Connect

A hybrid solar cell is designed and proposed as a feasible and reasonable alternative, according to acquired efficiency with the employment of zinc oxide (ZnO) nanorods and ZnO thin films at the same time. Both of these ZnO structures were grown electrochemically and poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester; (P3HT:PCBM) was used as an active polymer blend, which was found to be compatible to prepared indium-tin-oxide (ITO) substrate base. This ITO base was introduced with mentioned ZnO structure in such a way that, the most efficient configuration was optimized to be ITO/ZnO film/ZnO nanorod/P3HT: PCBM/Ag. Efficiency of this optimized device is found to be 2.44%. All ZnO works were carried out electrochemically, that is indeed for the first time and at relatively lower temperatures. (author)

Hames, Yakup [Department of Electrical-Electronics Engineering, Mustafa Kemal University, 31040 Hatay (Turkey); Alpaslan, Zuehal; Koesemen, Arif; San, Sait Eren; Yerli, Yusuf [Department of Physics, Gebze Institute of Technology, 41400 Gebze (Turkey)

2010-03-15

265

High performance solid oxide fuel cell cathode fabricated by electrochemical vapor deposition  

SciTech Connect

La(Sr)MnO[sub 3] cathodes have been investigated as high temperature oxygen reduction electrodes in the solid oxide fuel cells (SOFCs). The cathodes consist of 10 mole percent of yttria stabilized zirconia (YSZ) thin film electrolyte layer deposited on a porous La[sub 0.81]Sr[sub 0.09]MnO[sub 3] tube using the electrochemical vapor deposition method. The La(Sr)MnO[sub 3]/YSZ cathodes have different electrochemical properties from those fabricated with the sintering method. The cathode polarization was about 1 mV at a current density of 1.5 A/cm[sup 2] in oxygen at 1,000 C. This type of cathode has an extremely large phase boundary and large interfacial capacitance (more than 1 F/cm[sup 2]) which is approximately proportional to the oxygen partial pressure.

Suzuki, Minoru; Sasaki, Hirokazu; Otoshi, Shoji; Kajimura, Atsuko; Sugiura, Nozomi; Ippommatsu, Masamichi (Osaka Gas Co. Ltd. (Japan). Fundamental Research Labs.)

1994-07-01

266

Verification of p-n junctions in polymer light-emitting electrochemical cells via electrical characterization  

NASA Astrophysics Data System (ADS)

We report micrometer thick sandwich light-emitting electrochemical cells (LECs) based on a blend of poly[5-(2'-ethylhexyloxy)-2-methoxy-1, 4-phenylene vinylene] and poly(ethylene oxide) complexed with lithium trifluoromethanesulfonate. These LECs exhibit very similar properties as those of thin LECs including bipolar current-voltage characteristics and light emission. Mixing of aluminum nanoparticles into polymer layers improves electroluminescence because of smaller series resistance and larger light-emitting area. Taking series resistance into account, we confirm the operating mechanism of an LEC is the formation of a p-n junction by in situ electrochemical doping via fitting the steady state current-voltage characteristics to the expression for the Shockley model of a p-n diode.

Lei, Yueqing; Teng, Feng; Hou, Yanbing; Lou, Zhidong; Wang, Yongsheng

2009-09-01

267

Polymerizable ionic liquids for fixed junction light-emitting electrochemical cells  

NASA Astrophysics Data System (ADS)

Fixed junction light-emitting electrochemical cells (LECs) have been shown to offer several advantages over traditional dynamic junction LECs. Recently we have reported fixed junction LECs that use ion-pair monomers (IPMs) in order to eliminate counterionic mobility. However, the materials presented in our previous work had poor miscibility of IPMs with electroluminescent polymers and poor ion dissociation/mobility. Here we report on the synthesis and performance of polymerizable ionic liquids (PILs) as candidates for ionic charge carriers in LEC device structures. PILs are advantageous since they combine the improved materials properties of ionic liquids with the fixed-junction functionality of IPMs. Devices employing PILs had uniform film morphology and showed diode-like behavior. In addition, brightness was improved by an order of magnitude compared to IPM based devices reported earlier. The materials developed here, besides having advantages in LECs, may also find utility in additional applications in which control over ionic mobility or electrochemical doping is crucial.

Kosilkin, Ilya; Martens, Matt; Murphy, Michael; Leger, Janelle

2010-03-01

268

Thin-film electrochemical power cells. Final report  

SciTech Connect

Fundamental properties of research cells were correlated with the projected performance of full scale power sources, considering both battery and supercapacitor concepts. In addition to establishing the data base for modelling and performance projections, the program had the additional objective of identifying loss mechanisms and degradation reactions, especially those unique to polymer thin film cell designs. Because of the intrinsic high electrode/electrolyte interface areas, interfacial reactions must be understood. Many applications require power under extreme conditions, and low temperature performance needs to be improved.

Owens, B.B.; Smyrl, W.H.

1991-01-01

269

Electrochemical diffusimetry of fuel cell gas diffusion layers  

Microsoft Academic Search

The gas diffusion layers (GDLs) of a membrane electrode assembly (MEA) serve as link between flow field and porous electrode within a polymer electrolyte fuel cell. Beside ensuring sufficient electrical and thermal contact between the whole electrode area and the flow field, these typically 200–400?m thick porous structures enable the access of educts to the electrode area which would be

Denis Kramer; Stefan A. Freunberger; Reto Flückiger; Ingo A. Schneider; Alexander Wokaun; Felix N. Büchi; Günther G. Scherer

2008-01-01

270

Fabrication of carbon nanotubes/RGD peptide composites to enhance electrochemical performance of cell chip.  

PubMed

A cell chip is a valuable tool to evaluate the effects of anticancer drugs, antibiotics and environmental toxicants on various kinds of cells. In this study, a conductive composite material composed of multi-walled carbon nanotubes (CNTs) and RGD-MAP-C peptide was fabricated on gold electrode surface for enhancing electrochemical signals from HEK293T cells. The topological characteristics and electrochemical performance of composite materials with different concentrations of CNTs were analyzed by scanning electron microscopy and cyclic voltammetry (CV), respectively. CNTs/RGD peptide composites (CP) electrode containing 20 microg/ml CNT was found to be excellent for improving the sensitivity of cell chip compared with that of bare gold or RGD peptide modified electrode. Finally, two kinds of nephrotoxic antibiotics were treated to HEK293T cells and their toxicity were successfully monitored by CV. Our CP composites can be used as a suitable conducting material for the fabrication of various kinds of cell-based chips. PMID:23926807

Cho, Hyeon-Yeol; Eun-Bi-Ko; Kim, Tae-Hyung; Choi, Jeong-Woo

2013-08-01

271

Studies of lithium intercalation into carbons using nonaqueous electrochemical cells  

SciTech Connect

This paper discusses how Li/graphite and Li/petroleum coke cells using a 1{ital M} LiAsF{sub 6} in a 50:50 mixture of propylene carbonate (PC) and ethylene carbonate (EC) electrolyte exhibit irreversible reactions only on the first discharge. These irreversible reactions are associated with electrolyte decomposition and cause the formation of a passivating film or solid electrolyte interphase on the surface of the carbon. The amount of electrolyte decomposition is proportional to the specific surface area of the carbon electrode. When all the available surface area is coated with the film of decomposition products, further decomposition reactions stop. In subsequent cycles, these cells exhibit excellent reversibility and can be cycled without capacity loss.

Fong, R.; von Sacken, U.; Dahn, J.R. (Moli Energy Limited, Burnaby Columbia V5C 4G2 (CA))

1990-07-01

272

Electrochemical and flow characterization of a direct methanol fuel cell  

Microsoft Academic Search

Two-phase phenomena, i.e. bubble flow in the anode and water flooding in the cathode, are critical to design of high-performance direct methanol fuel cells (DMFC). A 5cm2 transparent DMFC has been developed to visualize these phenomena in situ. Two types of membrane-electrode assembly (MEA) based on Nafion® 112 were used to investigate effects of backing pore structure and wettability on

G. Q. Lu; C. Y. Wang

2004-01-01

273

An optically transparent thin-layer electrochemical cell for the study of vibrational circular dichroism of chiral redox-active molecules  

NASA Astrophysics Data System (ADS)

An optically transparent thin-layer electrochemical (OTTLE) cell with a locally extended optical path has been developed in order to perform vibrational circular dichroism (VCD) spectroscopy on chiral molecules prepared in specific oxidation states by means of electrochemical reduction or oxidation. The new design of the electrochemical cell successfully addresses the technical challenges involved in achieving sufficient infrared absorption. The VCD-OTTLE cell proves to be a valuable tool for the investigation of chiral redox-active molecules.

Domingos, Sérgio R.; Luyten, Henk; van Anrooij, Fred; Sanders, Hans J.; Bakker, Bert H.; Buma, Wybren J.; Hartl, František; Woutersen, Sander

2013-03-01

274

Electrical and Electrochemical Performance Characteristics of Small Commercial Li-Ion Cells  

SciTech Connect

Advanced rechargeable lithium-ion batteries are presently being developed and commercialized worldwide for use in consumer electronics, military and space applications. At Sandia National Laboratories we have used different electrochemical techniques such as impedance and charge/discharge at ambient and subambient temperatures to probe the various electrochemical processes that are occurring in Li-ion cell. The purpose of this study is to identify the component that reduces the cell performance at subambient temperatures. Our impedance data suggest that while the variation in the electrolyte resistance between room temperature and {minus}20 C is negligible the anode electrolyte interfacial resistance increases by an order of magnitude in the same temperature regime. We believe that the solid electrolyte interface (SEI) layer on the carbon anode may be responsible for the increase in cell impedance. We have also evaluated the cells in hybrid mode with capacitors. High-current operation in the hybrid mode allowed fill usage of the Li-ion cell capacity at 25 C and showed a factor of 5 improvement in delivered capacity at {minus}20 C.

Ingersoll, D.; Nagasubramanian, G.; Roth, E.P.

1998-12-22

275

Aptamer-aided target capturing with biocatalytic metal deposition: an electrochemical platform for sensitive detection of cancer cells.  

PubMed

A novel aptamer biosensor for cancer cell assay has been reported on the basis of ultrasensitive electrochemical detection. Cancer cell capturing is first accomplished via aptamer-aided recognition, and the cell-aptamer binding events then mediate an alkaline phosphatase-catalyzed silver deposition reaction which can be probed by electrochemical detection. Following biocatalytic silver deposition, an efficient amplification approach for sensitive electrochemical measurements is demonstrated, for cell detection with high sensitivity. Ramos cell are used as a model case, a typical biomarker of the acute blood cell cancer, Burkitt's lymphoma. The results reveal that the developed technique displays desirable selectivity in Ramos cell discrimination, and linear response range from 10 to 10(6) cells with a detection limit as low as 10 cells. Due to the simple procedures, label-free and electrochemistry based detection format, this technique is simple and cost-effective, and exhibits excellent compatibility with miniaturization technologies. The electrochemical cell detection strategy may create an intrinsically specific and sensitive platform for cancer cell assay and associated studies. PMID:23420020

Yi, Zi; Li, Xiao-Yan; Gao, Qing; Tang, Li-Juan; Chu, Xia

2013-02-18

276

Electrochemical oxidation in solid oxide fuel cells -- Where does it occur and how?  

NASA Astrophysics Data System (ADS)

Electrochemical processes in solid-oxide fuel cells (SOFCs) are thought to occur at a ``triple phase boundary'' (TPB) -- that junction between a conducting anode, a solid oxide electrolyte and the gas phase fuel mixture. A quantitative, physical description of this boundary, however, remains elusive given difficulties associated with probing molecular species present in SOFCs under realistic operating conditions of high temperatures and reducing atmospheres. Recently, we have constructed an SOFC that has optical access to the anode assembly allowing us to probe with Raman spectroscopy the chemical intermediates present on anode and electrolyte surfaces as carbon containing fuels are electrochemically oxidized. Results show that chemistry occurs on both the anode and electrolyte surfaces as well as in the vicinity of the purported TPB. The reduced electrolyte surface is both catalytically active and, over micron distances, electrically conductive. The Ni anode shows strong evidence of adsorbed carboxylate intermediates. This talk will address mechanisms of electrochemical oxidation in SOFCs using direct and indirect experimental probes as well as the consequence of our findings for models of a well defined triple phase boundary.

Walker, Robert; Pomfret, Michael

2006-03-01

277

Electrochemical oxidation of cyanide in the hydrocyclone cell  

SciTech Connect

A diluted electroplating cyanide rinse water has been used to test the use of the hydrocyclone cell (HCC) in batch recycle mode of operation for the simultaneous oxidation of cyanide during the electrodeposition of silver. The results obtained in this work with regard to the final products, current efficiency and the number of transferred electrons per CN{sup {minus}} helped to establish a probable reaction scheme. According to this, the process occurs mainly with one-electron transfer, through cyanate and cyanogen as intermediate species. Meanwhile, under conditions where the electrolyte circulates in an open bath and flows successively through the cathodic and the anodic compartments, as in the case of the HCC system, the cyanate could be produced by the direct oxidation through air and/or generated peroxide and CN could be lost as HCN (g).

Dhamo, N. [TU Berlin (Germany). Inst. fuer Metallurgie

1996-12-31

278

A dual-electrochemical cell to study the biocorrosion of stainless steel.  

PubMed

The presence of microorganisms on metal surfaces can alter the local physical/chemical conditions and lead to microbiologically influenced corrosion (MIC). The goal of the present work was to study the effect of a mixed aerobic-anaerobic biofilm on the behaviour of stainless steel (316 L) in underground conditions. Rather than testing different bacteria or consortia, investigations were based on the mechanisms of MIC. Mixed biofilms were simulated by the addition of glucose oxidase to reproduce the aerobic conditions and by sulphide or sulphate-reducing bacteria (SRB) for the anaerobic conditions. A double thermostated electrochemical cell has been developed to study the coupling between aerobic and anaerobic conditions. Results suggested a transfer of electrons from the stainless steel sample of the anaerobic cell to the stainless steel sample of the aerobic one. Inorganic sulphide was replaced by SRB in the anaerobic cell revealing an increase of the galvanic current which may be explained by an effect of lactate and/or acetate on the anodic reaction or by a high sulphide concentration in the biofilm. The results of this study underline that the dual-electrochemical cell system is representative of phenomena present in natural environments and should be considered as an option when studying MIC. PMID:17547022

Lopes, F A; Perrin, S; Féron, D

2007-01-01

279

Electrochemical Performance and Microbial Characterization of Thermophilic Microbial Fuel Cells  

NASA Astrophysics Data System (ADS)

Significant research effort is currently focused on microbial fuel cells (MFC) as a source of renewable energy. To date, most of these efforts have concentrated on MFCs operating at mesophilic temperatures. However, many previous studies have reported on the superiority of thermophilic conditions in anaerobic digestion and demonstrated a net gain in energy yield, in terms of methane, relative to the increased energy requirements of operation. Because of this, our recent studies on MFCs focused on investigating the operation and microbiology associated with thermophilic MFCs operating at 55°C. Over 100-day operation, these MFCs were highly stable and achieved a maximum power density of 24mW/m2 and a columbic efficiency of 89 percent with acetate as the sole electron donor. In order to characterize the microbial community involved in thermophilic electricity generation, DNA and RNA were isolated from the electrode and PhyloChip analyses performed. Exploring the changes in the microbial community over time in electricity producing MFC revealed an increase in relative abundance of populations belonging to the Firmicutes, Chloroflexi, and alpha Proteobacteria by at least one order of magnitude. In contrast, these populations decreased in the open circuit and no electron donor amended controls. In order to better characterize the active microbial populations, we enriched and isolated a novel organism, strain JR, from samples collected from an operating MFC. Based on 16S rRNA sequence analysis strain JR was a member of the family Peptococcaceae, within the Phylum Firmicutes, clustering with Thermincola ferriacetica (98 percent similarity). Phenotypic characterization revealed that strain JR was capable of thermophilic dissimilatory reduction of insoluble electron acceptors such as amorphous Fe(III); as well as reduction of the model quinone 2,6-anthraquinone disulfonate. Thermincola strain JR was also capable of producing current by coupling acetate oxidation to anodic electron transfer. This represents the first organism isolated from a thermophilic microbial fuel cell and also the first representative of this genus capable of anodic electron transfer. The results of this study indicate the potential advantages for thermophilic MFCs and the novel microbiology associated with their operation.

Wrighton, K. C.; Agbo, P.; Brodie, E. L.; Weber, K. A.; Desantis, T. Z.; Anderson, G. L.; Coates, J. D.

2007-12-01

280

Biclonal light chain gammopathy with aberrant CD33 expression in secondary plasma cell leukemia  

PubMed Central

Plasma cell leukemia is a rare neoplastic proliferation of circulating plasma cells. Clonal proliferations of plasma cells, such as in plasma cell leukemia or plasma cell myeloma, are typically characterized by production of a monoclonal heavy and/or light chain immunoglobulin. We present a case of a secondary plasma cell leukemia arising from plasma cell myeloma with dual expression of lambda and kappa light chains along with aberrant expression of CD33, CD20, and dim CD56. This case emphasizes the importance of recognizing aberrant immunophenotypes in plasma cell leukemias and represents the first reported case of biclonal light chain expression in a secondary plasma cell leukemia.

Gentry, Michael; Pettenati, Mark; Pang, Changlee S

2013-01-01

281

Electrochemical construction  

DOEpatents

An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

Einstein, Harry (Springfield, NJ); Grimes, Patrick G. (Westfield, NJ)

1983-08-23

282

Test report for measurement of performance vs temperature of Whittaker Electrochemical Cell  

SciTech Connect

This document is the test report that summarizes the results of the tests on the Whittaker cells between the temperatures of -20{degrees}F and +120{degrees}F. These sensors are used on the Rotary Mode Core Sampling (RMCS) flammable gas interlock (FGI), to detect and quantify hydrogen gas. The test consisted of operating five Whittaker electrochemical cells in an environmental chamber that was varied in temperature from -20{degrees}F to +120{degrees}F. As the rate rise of the voltage from the cells changed, after exposure to a gas concentration of 1% hydrogen at the different temperatures, the voltage was recorded on a computer controlled data acquisition system. Analysis of the data was made to determine if the cells maximum output voltages and rise times were effected by temperature.

Vargo, G.F., Fluor Daniel Hanford

1997-02-13

283

Teaching Cell Division to Secondary School Students: An Investigation of Difficulties Experienced by Turkish Teachers  

ERIC Educational Resources Information Center

|This study examines the difficulties biology teachers face when teaching cell division in the secondary schools of the central part of the Erzurum province in Turkey. During this research, a questionnaire was distributed to a total of 36 secondary school biology teachers. Findings of the study indicate biology teachers perceive cell division as…

Oztap, Haydar; Ozay, Esra; Oztap, Fulya

2003-01-01

284

Role for rearranged variable gene segments in directing secondary T cell receptor recombination  

Microsoft Academic Search

During the recombination of variable (V) and joining (J) gene segments at the T cell receptor ? locus, a V?J? joint resulting from primary rearrangement can be replaced by subsequent rounds of secondary rearrangement that use progressively more 5? V? segments and progressively more 3? J? segments. To understand the mechanisms that target secondary T cell receptor ? recombination, we

Abbas Hawwari; M. S. Krangel

2007-01-01

285

Planar polymer light-emitting electrochemical cells with extremely large interelectrode spacing  

NASA Astrophysics Data System (ADS)

Planar polymer light-emitting electrochemical cells have been demonstrated with interelectrode spacings nearly 100 times larger than previously reported. Striking details of the p-i-n junction structure have been imaged directly using a digital camera. With an interelectrode spacing of 1.5 mm, a well-defined emission zone over 70 ?m wide is observed near the cathode. Imaging under UV excitation reveals that the p-doped region migrates towards the cathode during operation, causing the emission zone at its frontier to shift. The width of the p-doped region is found to have a large variance, giving rise to an irregularly shaped emission zone.

Gao, Jun; Dane, Justin

2003-10-01

286

Study of magneto-electroluminescence and magneto-conductance in polymer light-emitting electrochemical cells  

NASA Astrophysics Data System (ADS)

Magneto-electroluminescence (MEL) and magneto-conductance (MC) have been investigated in polymer light-emitting electrochemical cells based on ``super-yellow'' poly-(phenylene vynilene) (SY-PPV). We measured positive MEL(B) and MC(B) responses that show a modified Lorentzian shape for B < 120 mT. At B < 2 mT, both MEL(B) and MC(B) responses show a second component, opposite in sign to the higher field response. We interpret the magnetic field response using the polaron pair model, from which we extract the hyperfine interaction constant of polarons in the SY-PPV polymer.

Ni, G.; Nguyen, T. D.; Vardeny, Z. V.

2011-06-01

287

Analytical analysis of the generic SET and RESET characteristics of electrochemical metallization memory cells.  

PubMed

We report on an analytical model which describes the bipolar resistive switching in electrochemical metallization cells. To simulate the resistive switching, we modeled the growth and dissolution of a metallic filament together with electron tunneling between the growing filament and the counter electrode. The model accounts for the controllability of the low resistive state and the RESET current by tuning the SET current. By analytical analysis the relevant conditions for these generic characteristics are identified. In addition, an explanation for the asymmetry in the SET and RESET switching characteristics is presented. The results of the analytical analysis is generalized to all types of ReRAMs. PMID:24065212

Menzel, Stephan; Waser, Rainer

2013-09-25

288

Hydrophilic Electrode For An Alkaline Electrochemical Cell, And Method Of Manufacture  

DOEpatents

A negative electrode for an alkaline electrochemical cell. The electrode comprises an active material and a hydrophilic agent constituted by small cylindrical rods of polyolefin provided with hydrophilic groups. The mean length of the rods is less than 50 microns and the mean diameter thereof is less than 20 microns. A method of manufacturing a negative electrode in which hydrophilic rods are made by fragmenting long polyolefin fibers having a mean diameter of less than 20 microns by oxidizing them, with the rods being mixed with the active material and the mixture being applied to a current conductor.

Senyarich, Stephane (Mornac, FR); Cocciantelli, Jean-Michel (Bordeaux, FR)

2000-03-07

289

Electrochemical performance of all-solid-state lithium secondary batteries with Li–Ni–Co–Mn oxide positive electrodes  

Microsoft Academic Search

LiNi1\\/3Co1\\/3Mn1\\/3O2 was applied as a promising material to the all-solid-state lithium cells using the 80Li2S·19P2S5·1P2O5 (mol%) solid electrolyte. The cell showed the first discharge capacity of 115mAhg?1 at the current density of 0.064mAcm?2 and retained the reversible capacity of 110mAhg?1 after 10 cycles. The interfacial resistance was observed in the impedance spectrum of the all-solid-state cell charged to 4.4V (vs.

Hirokazu Kitaura; Akitoshi Hayashi; Kiyoharu Tadanaga; Masahiro Tatsumisago

2010-01-01

290

Electrolytic cell and methods combining electrowinning and electrochemical reactions employing a membrane or diaphragm  

SciTech Connect

A process is described for combining at compatible cell geometries and current densities the electrowinning of a free metal element on a cathode in a catholytic electrolyte in a cell in which there is an anode with an anolytic electrolyte with a cationic permselective membrane between the catholytic electrolyte and anolytic electrolyte thereby forming a catholytic half-cell compartment and an anolytic half-cell compartment. The voltage for the combined catholytic half-cell and anolytic half-cell is reduced greater than 50% as compared to the sum of the cell voltages of two independently operating nonmembrane cells using an electrolyte selected from the catholytic electrolyte or the anolytic electrolyte and with water electrolysis at the anode. The process consists of (a) introducing a metal sulfate salt into the catholytic electrolyte in the half-cell catholytic compartment (b) introducing an alkali metal chlorate and an alkali metal perchlorate into the anolytic electrolyte in the half-cell anolytic compartment; and (c) applying an electromotive force across the cathode and anode whereby an oxidation electrochemical reaction occurs at the anode to produce a perchlorate while the free metal element of the metal salt is deposited at the cathode.

Smith, G.R.; Thompson, W.R.

1986-12-09

291

Patterned cell development in the secondary phloem of dicotyledonous trees: a review and a hypothesis  

Microsoft Academic Search

The secondary phloem of dicotyledonous trees and shrubs is constructed of sieve tube cells (S) and their companion cells, as well as parenchyma (P) and fibre (F) cells. Different species have characteristic sequences of these S, P and F cells within the radial files of their phloem. The sequences are recurrent, and are evidence of rhythmic cell determination and differentiation.

Peter W. Barlow; Jacqueline Lück

2006-01-01

292

Xylogenesis in tissue culture II: Microtubules, cell shape and secondary wall patterns  

Microsoft Academic Search

Summary InZinnia suspension cultures, two general categories of tracheary element (TE) secondary wall patterns can be distinguished: bands and webs. Band patterns are found in elongated cells or regions of cells, web patterns in isodiametric cells or regions of cells. Interphase cortical microtubule arrays, organized before overt differentiation occurs, determine both the shape of the cell and whether band or

Marcia M. Falconer; R. W. Seagull

1986-01-01

293

Electrochemical study of the effect of functionalized nickel nanoparticles on cellular uptake of leukemia cancer cells in vitro  

Microsoft Academic Search

In this study, we have fabricated the functionalized nickel nanoparticles and investigated their effects on cellular uptake of quercetin in leukemia K562 cancer cells by using electrochemical assay. The results indicate that nickel nanoparticles could efficiently enhance the quercetin uptake and increase the intracellular accumulation in cancer cells, implying the great potential of functionalized nickel nanoparticles in target cancer therapy.

Da Dong Guo; Chun Hui Wu; Xue Mei Wang; Bao An Chen

2008-01-01

294

Electrochemical study of Type 304 and 316L stainless steels in simulated body fluids and cell cultures  

Microsoft Academic Search

The electrochemical corrosion behaviour of Type 304 and 316L stainless steels was studied in Hanks’ solution, Eagle’s minimum essential medium (MEM), serum containing medium (MEM with 10% of fetal bovine serum) without cells, and serum containing medium with cells over a 1-week period. Polarization resistance measurements indicated that the stainless steels were resistant to Hanks’ and MEM solutions. Type 304

Yee-Chin Tang; Shoji Katsuma; Shinji Fujimoto; Sachiko Hiromoto

2006-01-01

295

Survey of genes involved in rice secondary cell wall formation through a co-expression network.  

PubMed

The plant secondary cell wall is the major source of lignocellulosic biomass, a renewable energy resource that can be used for bioethanol production. To comprehensively identify transcription factors (TFs), glycosyltransferase (GT) and glycosyl hydrolase (GH) involved in secondary cell wall formation in rice (Oryza sativa), co-expression network analysis was performed using 68 microarray data points for different rice tissues and stages. In addition to rice genes encoding orthologs of Arabidopsis thaliana TFs known to regulate secondary cell wall formation, the network analysis suggested many novel TF genes likely to be involved in cell wall formation. In the accompanying paper (Hirano et al.), several of these TFs are shown to be involved in rice secondary cell wall formation. Based on a comparison of the rice and Arabidopsis networks, TFs were classified as common to both species or specific to each plant species, suggesting that in addition to a common transcriptional regulatory mechanism of cell wall formation, the two plants may also use species-specific groups of TFs during secondary wall formation. Similarly, genes encoding GT and GH were also classified as genes showing species-common or species-specific expression patterns. In addition, genes for primary or secondary cell wall formation were also suggested. The list of rice TF, GT and GH genes provides an opportunity to unveil the regulation of secondary cell wall formation in grasses, leading to optimization of the cell wall for biofuel production. PMID:24089433

Hirano, Ko; Aya, Koichiro; Morinaka, Yoichi; Nagamatsu, Shiro; Sato, Yutaka; Antonio, Baltazar A; Namiki, Nobukazu; Nagamura, Yoshiaki; Matsuoka, Makoto

2013-10-01

296

Electrochemical immunoassay of membrane P-glycoprotein by immobilization of cells on gold nanoparticles modified on a methoxysilyl-terminated butyrylchitosan matrix.  

PubMed

A strategy to detect P-glycoprotein (P-gp) on cell membrane and quantify the cell number using electrochemical immunoassay was developed by effective surface immunoreactions and immobilization of cells on a highly hydrophilic interface, which was constructed by adsorption of colloidal gold nanoparticles on a methoxysilyl-terminated (Mos) butyrylchitosan modified glassy carbon electrode (Au-CS/GCE). Atomic force microscopy studies proved that the nanoparticles adsorbed on Mos-butyrylchitosan were efficient in preventing the cell leakage and retaining the activity of immobilized living K562/ADM leukemic cells. The incubation with P-gp monoclonal antibody and then the secondary alkaline phosphatase (AP) conjugated antibody introduced AP onto the K562/ADM cell immobilized on Au-CS/GCE. The bound AP led to an amperometric response of 1-naphthyl phosphate. Under optimal conditions the response was proportional to the logarithm of cell concentration in the range from 5.0 x 10(4) to 1.0 x 10(7) cells mL(-)(1) with a detection limit of 1.0 x 10(4) cells mL(-)(1). The results were comparable to flow cytometric analysis of P-gp expression. This proposed method was practical, convenient, and significant in the clinic and cytobiology. PMID:16114890

Du, Dan; Ju, Huangxian; Zhang, Xueji; Chen, Jing; Cai, Jie; Chen, Hongyuan

2005-08-30

297

Single cells and intracellular processes studied by a plasmonic-based electrochemical impedance microscopy  

PubMed Central

We report an electrochemical impedance microscope (EIM) based on surface plasmon resonance. The new EIM can resolve local impedance with sub-micron spatial resolution, and monitor dynamics of various processes, such as apoptosis and electroporation of individual cells with millisecond time resolution. The high spatial and temporal resolution images make it possible to not only study individual cells, but also resolve the sub-cellular structures and processes without labels. The detection sensitivity achieved with the current setup is ~2 pS, which is excellent considering the conductance of a single ion channel is in the range of 5–400 pS. We describe also a model that simulates the EIM images of cells based on local dielectric constant and conductivity.

Wang, Wei; Foley, Kyle; Shan, Xiaonan; Wang, Shaopeng; Eaton, Seron; Nagaraj, Vinay J; Wiktor, Peter; Patel, Urmez; Tao, Nongjian

2012-01-01

298

Semiconductor photo-electrochemical solar cells based on admixing of nano-materials for renewable energy  

Microsoft Academic Search

We studied a new type of TiO2-WO3 admixed septum-based semiconductor photo-electrochemical (SC-SEP, PEC) solar cell for photo-electro chemical measurement and hydrogen production. The SC-SEP cell in the configuration of SCE\\/1 M NaOH\\/TiO2 (ns)\\/Ti\\/H2SO4 + K2SO4\\/PtCE, PtWE showed photo-voltage and photo-current of 0.72?V and 8.6 mA\\/cm, respectively, whereas the SC-SEP cell employing WO3 admixed TiO2 (ns) photo-electrode with the configuration: SCE\\/1

Mridula Tripathi; Ruby Upadhyay; Ashutosh Pandey

2012-01-01

299

Electrodes and method of preparation thereof for use in electrochemical cells  

SciTech Connect

This invention relates to novel electrodes and a method of preparation thereof for use in electrochemical cells. The novel electrodes contain a combination of electrocatalysts deposited on a metal substrate. The electrocatalysts are deposited from a homogeneous solution of the compounds of (A) at least one metal selected from iron, cobalt, manganese and nickel, (B) at least one metal selected from molybdenum, vanadium and tungsten, and (C) at least one rare earth metal of the lanthanide group having an atomic number of 57-71 inclusive, the metal compounds are decomposed to the oxide and the oxide coated substrate cured at elevated temperature in a reducing atmosphere. The electrodes thus produced can be used as an anode or as a cathode in fuel cells and in cells for the electrolysis of water or brines.

Brown, D.E.; Hall, S.M.; Mahmood, M.N.

1982-08-03

300

Fabrication of electrolytic cell for online post-column electrochemical derivatization in ion chromatography.  

PubMed

An electrolytic cell (EC), composed of two ruthenium-plated titanium electrodes separated by cation-exchange membranes, was fabricated and evaluated for online postcolumn derivatization in ion chromatography (IC). Folic acid (FA) and methotrexate (MTX) were preliminarily used as prototype analytes to test the performance of EC. After separation by an anion exchange column, FA and MTX, which emit very weak fluorescence when excited, were electrochemically oxidized online in the anode chamber of the EC. The compounds with strong fluorescence, which are oxidation products, were detected by the fluorescence detector. The phosphate buffer solution (100 mM KH(2)PO(4)) served as an optimal eluent for anion exchange chromatographic separation and a suitable supporting electrolyte for electro-oxidation, leading to ideal compatibility between IC separation and the postcolumn electrochemical derivatization. For the presently proposed method, the linear ranges were from 0.01 mg L(-1) to 5 mg L(-1) for both FA and MTX. The detection limits of FA and MTX were 1.8 and 2.1 ?g L(-1), and the relative standard deviations (RSD, n=7) were 2.9% and 3.6%, respectively. The method was applied for the simultaneous determination of FA and MTX in the plasma of patients being treated for rheumatoid arthritis. The determination of MTX in the urine of the patients of diffuse large B cell lymphoma was also demonstrated. PMID:22713918

Wu, Shuchao; Xu, Wei; Yang, Bingcheng; Ye, Mingli; Zhang, Peimin; Shen-Tu, Chao; Zhu, Yan

2012-05-19

301

Method of forming a plasma sprayed interconnection layer on an electrode of an electrochemical cell  

DOEpatents

A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO.sub.3 particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO.sub.3 powder, preferably compensated with chromium as Cr.sub.2 O.sub.3 and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO.sub.3 layer to about 1100.degree. C. to 1300.degree. C. to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the unselected portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell.

Spengler, Charles J. (Murrysville, PA); Folser, George R. (Lower Burrell, PA); Vora, Shailesh D. (Monroeville, PA); Kuo, Lewis (Monroeville, PA); Richards, Von L. (Anyola, IN)

1995-01-01

302

Method of forming a plasma sprayed interconnection layer on an electrode of an electrochemical cell  

DOEpatents

A dense, substantially gas-tight, electrically conductive interconnection layer is formed on an air electrode structure of an electrochemical cell by (A) providing an electrode surface; (B) forming on a selected portion of the electrode surface, a layer of doped LaCrO{sub 3} particles doped with an element selected from Ca, Sr, Ba, Mg, Co, Ni, Al and mixtures thereof by plasma spraying doped LaCrO{sub 3} powder, preferably compensated with chromium as Cr{sub 2}O{sub 3} and/or dopant element, preferably by plasma arc spraying; and, (C) heating the doped and compensated LaCrO{sub 3} layer to about 1100 C to 1300 C to provide a dense, substantially gas-tight, substantially hydration-free, electrically conductive interconnection material bonded to the electrode surface. A solid electrolyte layer can be applied to the unselected portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell. 6 figs.

Spengler, C.J.; Folser, G.R.; Vora, S.D.; Kuo, L.; Richards, V.L.

1995-06-20

303

Electrochemical properties of lead oxide films obtained by spray pyrolysis as negative electrodes for lithium secondary batteries  

Microsoft Academic Search

Lead(II) oxides in bulk and thin film form were assessed as electrodes for lithium rechargeable batteries. Films were prepared by spray pyrolysis of aqueous solutions of Pb(CH3–COO)2·2H2O and deposited onto lead substrates at 175°C. Films heated at 250°C were found to consist of well-crystallized tetragonal PbO and evolve to the orthorhombic polymorph with prolonged heating. Cycling of the cells at

M. Martos; J. Morales; L. Sánchez; R. Ayouchi; D. Leinen; F. Martin; J. R. Ramos Barrado

2001-01-01

304

Conceptual Difficulties Experienced by Prospective Teachers in Electrochemistry: Half-Cell Potential, Cell Potential, and Chemical and Electrochemical Equilibrium in Galvanic Cells  

NASA Astrophysics Data System (ADS)

A previous study of prospective teachers found that students from different countries and different levels of electrochemistry hold common misconceptions, indicating that concepts were presented to them poorly. It also identified new misconceptions by considering electrochemical concepts such as chemical equilibrium, electrochemical equilibrium, and the instrumental requirements for the measurement of cell potential, which had been ignored in the literature. This paper reports how the prospective teachers' scientifically incorrect ideas were used to form assertion-reason-type questions and how these questions were used to identify previously unreported conceptual difficulties related to these ignored concepts. The origins of the learning difficulties were attributed to lack of electrochemical conceptual knowledge and to insufficient explanation of the concepts in the textbooks. The results of this study were consistent with the constructivist model of learning, which suggests that students construct new knowledge through their existing experiences and knowledge, and that some misconceptions may appear to be quite logical to students.

Riza Özkaya, Ali

2002-06-01

305

The immunosuppressive effect of embryonic stem cells and mesenchymal stem cells on both primary and secondary alloimmune responses  

Microsoft Academic Search

Recently, both embryonic stem cells and mesenchymal stem cells have been demonstrated to have immunosuppressive effects. The purpose of this study was to elucidate whether the embryonic stem cells and\\/or mesenchymal stem cells modulate both primary and secondary alloimmune responses. Both stem cells suppressed in vitro proliferation and cytokine production in primary alloimmune responses. They also suppressed in vitro proliferation

Kyu Hyun Han; Hee Gyung Kang; Hae Jin Gil; Eun Mi Lee; Curie Ahn; Jaeseok Yang

2010-01-01

306

New Li-alloy electrode for Li-alloy/metal sulfide cells  

DOEpatents

The present invention relates to electrodes for use in secondary electrochemical cells. More particularly, it concerns a method of making a negative electrode composition, the electrode composition made thereby and the secondary electrochemical cell containing the electrode, wherein the negative electrode composition includes a lithium alloy including silicon and nickel.

Kaun, T.D.

1994-12-31

307

The Lead-Lead Oxide Secondary Cell as a Teaching Resource  

ERIC Educational Resources Information Center

|The assembly and use of a laboratory version of a secondary cell based on the lead-lead oxide system is described. The cell is easy to construct, sufficiently robust for student use, and has a conveniently low practical capacity of about 5 mA h. This modest cell capacity allows cell assembly, electrode formation and discharge characterization…

Smith, Michael J.; Fonseca, Antonio M.; Silva, M. Manuela

2009-01-01

308

Solid polymer electrolyte electrochemical storage cell containing a redox shuttle additive for overcharge protection  

DOEpatents

A class of organic redox shuttle additives is described, preferably comprising nitrogen-containing aromatics compounds, which can be used in a high temperature (85.degree. C. or higher) electrochemical storage cell comprising a positive electrode, a negative electrode, and a solid polymer electrolyte to provide overcharge protection to the cell. The organic redox additives or shuttles are characterized by a high diffusion coefficient of at least 2.1.times.10.sup.-8 cm.sup.2 /second and a high onset potential of 2.5 volts or higher. Examples of such organic redox shuttle additives include an alkali metal salt of 1,2,4-triazole, an alkali metal salt of imidazole, 2,3,5,6-tetramethylpyrazine, 1,3,5-tricyanobenzene, and a dialkali metal salt of 3-4-dihydroxy-3-cyclobutene-1,2-dione.

Richardson, Thomas J. (Oakland, CA); Ross, Philip N. (Moraga, CA)

1999-01-01

309

Electrodes and electrochemical storage cells utilizing tin-modified active materials  

DOEpatents

An electrode has a substrate and a finely divided active material on the substrate. The active material is ANi.sub.x-y-z Co.sub.y Sn.sub.z, wherein A is a mischmetal or La.sub.1-w M.sub.w, M is Ce, Nd, or Zr, w is from about 0.05 to about 1.0, x is from about 4.5 to about 5.5, y is from 0 to about 3.0, and z is from about 0.05 to about 0.5. An electrochemical storage cell utilizes such an electrode as the anode. The storage cell further has a cathode, a separator between the cathode and the anode, and an electrolyte.

Anani, Anaba (Lauderhill, FL); Johnson, John (Calverton, NY); Lim, Hong S. (Agoura Hills, CA); Reilly, James (Bellport, NY); Schwarz, Ricardo (Los Alamos, NM); Srinivasan, Supramaniam (College Station, TX)

1995-01-01

310

Intracellular Cytokine Production by Dengue Virus-specific T cells Correlates with Subclinical Secondary Infection  

PubMed Central

The pathophysiology of dengue virus infection remains poorly understood, although secondary infection is strongly associated with more severe disease. In the present study, we performed a nested, case-control study comparing the responses of pre-illness peripheral blood mononuclear cells between children who would subsequently develop either subclinical or symptomatic secondary infection 6–11 months after the baseline blood samples were obtained and frozen. We analyzed intracellular cytokine production by CD4+ and CD8+ cells in response to stimulation with dengue antigen. We found higher frequencies of dengue virus–specific TNF?, IFN?-, and IL-2–producing T cells among schoolchildren who subsequently developed subclinical infection, compared with those who developed symptomatic secondary dengue virus infection. Although other studies have correlated immune responses during secondary infection with severity of disease, to our knowledge this is the first study to demonstrate a pre-infection dengue-specific immune response that correlates specifically with a subclinical secondary infection.

Hatch, Steven; Endy, Tim P.; Thomas, Stephen; Mathew, Anuja; Potts, James; Pazoles, Pamela; Libraty, Daniel H.; Gibbons, Robert

2011-01-01

311

Method of preparing a negative electrode including lithium alloy for use within a secondary electrochemical cell  

DOEpatents

A negative electrode that includes a lithium alloy as active material is prepared by briefly submerging a porous, electrically conductive substrate within a melt of the alloy. Prior to solidification, excess melt can be removed by vibrating or otherwise manipulating the filled substrate to expose interstitial surfaces. Electrodes of such a solid lithium--aluminum filled within a substrate of metal foam are provided. 1 figure, 1 table.

Tomczuk, Z.; Olszanski, W.; Battles, J.E.

1975-12-09

312

Open micro-fluidic system for atomic force microscopy-guided in situ electrochemical probing of a single cell.  

PubMed

Ultra-sharp nano-probes and customized atomic force microscopy (AFM) have previously been developed in our laboratory for in situ sub-cellular probing of electrochemical phenomena in living plant cells during their photosynthesis. However, this AFM-based electrochemical probing still has numerous engineering challenges such as immobilization of the live cells, compatibility of the immobilization procedure with AFM manipulation of the probe, maintenance of biological activity of the cells for an extended time while performing the measurements, and minimization of electrochemical noise. Thus, we have developed an open micro-fluidic channel system (OMFC) in which individual cells can be immobilized in micro-traps by capillary flow. This system affords easy AFM access and allows for maintenance of the cells in a well-defined chemical environment, which sustains their biological activity. The use of micro-channels for making the electrochemical measurements significantly reduces parasitic electrical capacitances and allows for current detection in the sub-pico-ampere range at high signal bandwidths. The OMFC was further studied using simulation packages for optimal design conditions. This system was successfully used to measure light-dependent oxidation currents of a few pico-amperes from the green alga Chlamydomonas reinhardtii. PMID:18818800

Ryu, Wonhyoung; Huang, Zubin; Sun Park, Joong; Moseley, Jeffrey; Grossman, Arthur R; Fasching, Rainer J; Prinz, Fritz B

2008-07-25

313

Lack of Relation between Secondary Hyperparathyroidism and Red Blood Cell Osmotic Fragility in Chronic Renal Failure  

Microsoft Academic Search

The possible relationship between red blood cell (RBC) osmotic fragility and secondary hyperparathyroidism (HPT) in chronic renal failure was examined in 23 uremic patients on conservative therapy and in 42 patients on maintenance hemodialysis. Secondary HPT was evaluated by means of serum biochemistry (parathyroid hormone, calcium, phosphorus, and alkaline phosphatase) and radiographic examinations (X-ray films of the hand skeleton). This

Dino Docci; Fausto Turci; Leopoldo Baldrati

1985-01-01

314

Electrochemical differential photoacoustic cell to study in situ the growing process of porous materials  

NASA Astrophysics Data System (ADS)

In order to study in situ the growing process of porous materials, a new electrochemical differential photoacoustic cell (DPC) was developed. This system allows to obtain the thermal signals coming from the growing process of the pores without the external noise component. The DPC is a good system to growth porous silicon and study their growing process with reproducibility. The porous silicon samples were obtained by using electrochemical etching of (100) n-type silicon wafers with different nominal resistivity values in the range of 1-25 ? cm. The samples were formed in a solution of hydrofluoric acid and ethanol having a composition ratio of 1:1 in volume with etching voltage of 10V and an etching time of 2 min using back illumination provided by a laser beam with a wavelength of 808 nm. The porous samples were characterized by means of Raman microscopy, x-ray diffraction, and scanning electron microscopy. The crystallite sizes of the samples were obtained through the analysis of the micro-Raman spectra using a phonon confinement model, and the analysis of the x-ray diffractograms.

Gutiérrez, Adriana; Giraldo, Jairo; Velázquez-Hernández, Rubén; Mendoza-López, Maria Luisa; Espinosa-Arbeláez, Diego G.; Del Real, Alicia; Rodríguez-García, Mario E.

2010-01-01

315

Photophysical and electrochemical properties, and molecular structures of organic dyes for dye-sensitized solar cells.  

PubMed

Dye-sensitized solar cells (DSSCs) based on organic dyes adsorbed on oxide semiconductor electrodes, such as TiO(2), ZnO, or NiO, which have emerged as a new generation of sustainable photovoltaic devices, have attracted much attention from chemists, physicists, and engineers because of enormous scientific interest in not only their construction and operational principles, but also in their high incident-solar-light-to-electricity conversion efficiency and low cost of production. To develop high-performance DSSCs, it is important to create efficient organic dye sensitizers, which should be optimized for the photophysical and electrochemical properties of the dyes themselves, with molecular structures that provide good light-harvesting features, good electron communication between the dye and semiconductor electrode and between the dye and electrolyte, and to control the molecular orientation and arrangement of the dyes on a semiconductor surface. The aim of this Review is not to make a list of a number of organic dye sensitizers developed so far, but to provide a new direction in the epoch-making molecular design of organic dyes for high photovoltaic performance and long-term stability of DSSCs, based on the accumulated knowledge of their photophysical and electrochemical properties, and molecular structures of the organic dye sensitizers developed so far. PMID:22807392

Ooyama, Yousuke; Harima, Yutaka

2012-07-16

316

Electrochemical cell and electrode designs for high-temperature/high-pressure kinetic measurements  

SciTech Connect

Many corrosion processes of interest to the nuclear power industry occur in high-temperature/high-pressure aqueous systems. The investigation of the kinetics of the appropriate electrode reactions is a serious experimental challenge, partially because of the high temperatures and pressures and partially because many of these reactions are very rapid, requiring fast relaxation measurements. An electrochemical measuring system is described which is suitable for measurements of the kinetics of fast electrode reactions at temperatures extending to at least 300C and pressures to at least 10 MPa (100 atmospheres). The system includes solution preparation and handling equipment, the electrochemical cell, and several electrode designs. One of the new designs is a coaxial working electrode-counter electrode assembly; this electrode can be used with very fast-rising pulses, and it provides a well defined, repeatedly-polishable working surface. Low-impedance reference electrodes are also described, based on electrode concepts responding to the pH or the redox potential of the test solution. Additionally, a novel, long-life primary reference electrode design is reported, based on a modification of the external, pressure-balanced Ag/AgCl reference electrode.

Nagy, Z.; Yonco, R.M.

1987-05-01

317

In situ X-ray diffraction of prototype sodium metal halide cells: Time and space electrochemical profiling  

Microsoft Academic Search

The feasibility of using energy dispersive X-ray diffraction to characterize full size battery cells is demonstrated by unprecedented in situ measurements of the electrochemical processes taking place inside high temperature sodium metal halide (Na\\/MCl2, M=Ni and\\/or Fe) cells during charge\\/discharge cycling. Diffraction data provide phase information either via line scans across the 5cm wide cells or via fixed location scans

Job Rijssenbeek; Yan Gao; Zhong Zhong; Mark Croft; Najeh Jisrawi; Alexander Ignatov; Thomas Tsakalakos

2010-01-01

318

Electrochemical and physical analysis of a Li-ion cell cycled at elevated temperature  

SciTech Connect

Laboratory-size LiNi0.8Co0.15Al0.05O2/graphite lithium-ion pouch cells were cycled over 100 percent DOD at room temperature and 60 degrees C in order to investigate high-temperature degradation mechanisms of this important technology. Capacity fade for the cell was correlated with that for the individual components, using electrochemical analysis of the electrodes and other diagnostic techniques. The high-temperature cell lost 65 percent of its initial capacity after 140 cycles at 60 degrees C compared to only 4 percent loss for the cell cycled at room temperature. Cell ohmic impedance increased significantly with the elevated temperature cycling, resulting in some of loss of capacity at the C/2 rate. However, as determined with slow rate testing of the individual electrodes, the anode retained most of its original capacity, while the cathode lost 65 percent, even when cycled with a fresh source of lithium. Diagnostic evaluation of cell components including XRD, Raman, CSAFM and suggest capacity loss occurs primarily due to a rise in the impedance of the cathode, especially at the end-of-charge. The impedance rise may be caused in part by a loss of the conductive carbon at the surface of the cathode and/or by an organic film on the surface of the cathode that becomes non-ionically conductive at low lithium content.

Shim, Joongpyo; Kostecki, Robert; Richardson, Thomas; Song, Xiangyun; Striebel, Kathryn A.

2002-06-21

319

Electrochemical fuel cell generator having an internal and leak tight hydrocarbon fuel reformer  

DOEpatents

An electrochemical fuel cell generator configuration is made having a generator section which contains a plurality of axially elongated fuel cells, each cell containing a fuel electrode, air electrode, and solid oxide electrolyte between the electrodes, in which axially elongated dividers separate portions of the fuel cells from each other, and where at least one divider also reforms a reformable fuel gas mixture prior to electricity generation reactions, the at least one reformer-divider is hollow having a closed end and an open end entrance for a reformable fuel mixture to pass to the closed end of the divider and then reverse flow and pass back along the hollowed walls to be reformed, and then finally to pass as reformed fuel out of the open end of the divider to contact the fuel cells, and further where the reformer-divider is a composite structure having a gas diffusion barrier of metallic foil surrounding the external walls of the reformer-divider except at the entrance to prevent diffusion of the reformable gas mixture through the divider, and further housed in an outer insulating jacket except at the entrance to prevent short-circuiting of the fuel cells by the gas diffusion barrier.

Dederer, Jeffrey T. (Valencia, PA); Hager, Charles A. (Mars, PA)

1998-01-01

320

Electrochemical fuel cell generator having an internal and leak tight hydrocarbon fuel reformer  

DOEpatents

An electrochemical fuel cell generator configuration is made having a generator section which contains a plurality of axially elongated fuel cells, each cell containing a fuel electrode, air electrode, and solid oxide electrolyte between the electrodes, in which axially elongated dividers separate portions of the fuel cells from each other, and where at least one divider also reforms a reformable fuel gas mixture prior to electricity generation reactions, the at least one reformer-divider is hollow having a closed end and an open end entrance for a reformable fuel mixture to pass to the closed end of the divider and then reverse flow and pass back along the hollowed walls to be reformed, and then finally to pass as reformed fuel out of the open end of the divider to contact the fuel cells, and further where the reformer-divider is a composite structure having a gas diffusion barrier of metallic foil surrounding the external walls of the reformer-divider except at the entrance to prevent diffusion of the reformable gas mixture through the divider, and further housed in an outer insulating jacket except at the entrance to prevent short-circuiting of the fuel cells by the gas diffusion barrier. 10 figs.

Dederer, J.T.; Hager, C.A.

1998-03-31

321

Microfluidic chip integrated with flexible PDMS-based electrochemical cytosensor for dynamic analysis of drug-induced apoptosis on HeLa cells.  

PubMed

A novel microfluidic platform integrated with a flexible PDMS-based electrochemical cytosensor was developed for real-time monitoring of the proliferation and apoptosis of HeLa cells. The PDMS-gold film, which had a conductive smooth surface and was semi-transparent, facilitated electrochemical measurements and optical microscope observations. We observed distinct increases and decreases in peak current intensity, corresponding to cell proliferation in culture medium and apoptosis in the presence of an anticancer drug, respectively. This electrochemical analysis method permitted real-time, label-free monitoring of cell behavior, and the electrochemical results were confirmed with optical microscopy. The flexible microfluidic electrochemical platform presented here is suitable for on-site monitoring of cell behavior in microenvironments. PMID:23942358

Cao, Jun-Tao; Zhu, Ying-Di; Rana, Rohit Kumar; Zhu, Jun-Jie

2013-07-19

322

Hybrid organic-inorganic light-emitting electrochemical cells using fluorescent polymer and ionic liquid blend as an active layer  

NASA Astrophysics Data System (ADS)

We demonstrate enhanced device performance by using a blend of emissive polymer and mobile ionic liquid molecules in hybrid organic-inorganic polymeric light-emitting electrochemical cells with high air stability. The mobile anions and cations redistributed near each electrode/active layer interface make ohmic contacts, thereby enhancing current density and electroluminescence efficiency at relatively low operating voltage.

Lee, Hyun Jung; Lee, Bo Ram; Park, Ji Sun; Kim, Sang Ouk; Kim, Jin Young; Song, Myoung Hoon

2011-06-01

323

Electrochemical studies of an unsupported PtIr electrocatalyst as a bifunctional oxygen electrode in a unitized regenerative fuel cell  

Microsoft Academic Search

The electrochemical performance of an unsupported PtIr electrocatalyst was evaluated as a bifunctional oxygen electrode in a unitized regenerative fuel cell (URFC). The catalyst was a mixture of unsupported Pt black and Ir black catalysts in varying proportions. The performance of the unsupported PtIr catalyst was studied by using a rotating ring disc electrode (RRDE) and linear sweep voltammetry (LSV).

Ho-Young Jung; Branko N. Popov

2009-01-01

324

Thermal and electrochemical durability of carbonaceous composites used as a bipolar plate of proton exchange membrane fuel cell  

Microsoft Academic Search

Thermal and electrochemical durability of carbonaceous composite plates, which are made from graphite powders and a resin for use as bipolar plates of PEMFC (proton exchange membrane fuel cell), were investigated. The thermal durability was investigated by TG (thermal gravimetry) coupled with DTA (differential thermal analysis) technique under air up to 600°C. A weight loss was significant over 300°C, but

Taro Kinumoto; Keita Nagano; Tomoki Tsumura; Masahiro Toyoda

2010-01-01

325

Hybrid organic-inorganic light-emitting electrochemical cells using fluorescent polymer and ionic liquid blend as an active layer  

Microsoft Academic Search

We demonstrate enhanced device performance by using a blend of emissive polymer and mobile ionic liquid molecules in hybrid organic-inorganic polymeric light-emitting electrochemical cells with high air stability. The mobile anions and cations redistributed near each electrode\\/active layer interface make ohmic contacts, thereby enhancing current density and electroluminescence efficiency at relatively low operating voltage.

Hyun Jung Lee; Bo Ram Lee; Ji Sun Park; Sang Ouk Kim; Jin Young Kim; Myoung Hoon Song

2011-01-01

326

Annotated Bibliography of the Thermal Properties of Primary and Secondary Cells.  

National Technical Information Service (NTIS)

The literature concerning the thermal properties of primary and secondary cells and batteries is listed under six main subject headings. These six headings are: Thermal conductivity and resistance data, and thermal resistance-capacitance models; Specific ...

E. W. Brooman

1970-01-01

327

Electroluminescence and electric current response spectroscopy applied to the characterization of polymer light-emitting electrochemical cells  

NASA Astrophysics Data System (ADS)

Frequency-dependent electroluminescence and electric current response spectroscopy were applied to polymeric light-emitting electrochemical cells in order to obtain information about the operation mechanism regimes of such devices. Three clearly distinct frequency regimes could be identified: a dielectric regime at high frequencies; an ionic transport regime, characterized by ionic drift and electronic diffusion; and an electrolytic regime, characterized by electronic injection from the electrodes and electrochemical doping of the conjugated polymer. From the analysis of the results, it was possible to evaluate parameters like the diffusion speed of electronic charge carriers in the active layer and the voltage drop necessary for operation.

Gozzi, Giovani; Mendonça Faria, Roberto; Fugikawa Santos, Lucas

2012-09-01

328

Ultraviolet and infrared spectroscopy for effluent analysis in a molten salt electrochemical cell  

NASA Astrophysics Data System (ADS)

An apparatus that combines gas phase spectroscopy over two wavelength ranges for analysis of effluent from a molten salt electrochemical cell is described. The cell is placed in a quartz tube that is sealed at the top with a cap containing feedthrus for power, thermometry, and gas flow. A resistance furnace brings the cell assembly to the desired temperature while the cap remains cooled by water. Inert gas continually purges the cell headspace carrying effluent from the electrolysis sequentially through two gas cells, one in a Fourier transform infrared (FTIR) spectrometer and one in a fiber-optic coupled ultraviolet visible spectrometer. Strong vibrational absorptions in the IR can easily identify common effluent components such as HCl, CO, CO2, and H2O. Electronic bands can identify IR-inactive molecules of importance including Cl2 and O2. Since the absorptivity of all of these species is known, determinations of the gas concentration can be made without using standards. Spectra from the electrolysis of molten MgCl2 are shown and discussed, as well as the limit of detection and inherent time resolution of the apparatus as implemented.

Moore, J. F.; Pellin, M. J.; Calaway, W. F.; Hryn, J. N.

2003-08-01

329

Glucose and Lactate Biosensors for Scanning Electrochemical Microscopy Imaging of Single Live Cells  

PubMed Central

We have developed glucose and lactate ultramicroelectrode (UME) biosensors based on glucose oxidase and lactate oxidase (with enzymes immobilized onto Pt UMEs by either electropolymerization or casting) for scanning electrochemical microscopy (SECM), and have determined their sensitivity to glucose and lactate, respectively. The results of our evaluations reveal different advantages for sensors constructed by each method: improved sensitivity and shorter manufacturing time for hand-casting, and increased reproducibility for electropolymerization. We have acquired amperometric approach curves (ACs) for each type of manufactured biosensor UME, and these ACs can be used as a means of positioning the UME above a substrate at a known distance. We have used the glucose biosensor UMEs to record profiles of glucose uptake above individual fibroblasts. Likewise, we have employed the lactate biosensor UMEs for recording the lactate production above single cancer cells with the SECM. We also show that oxygen respiration profiles for single cancer cells do not mimic cell topography, but are rather more convoluted, with a higher respiration activity observed at the points where the cell touches the Petri dish. These UME biosensors, along with the application of others already described in the literature, could prove to be powerful tools for mapping metabolic analytes, such as glucose, lactate and oxygen, in single cancer cells.

Ciobanu, Madalina; Taylor, Dale E.; Wilburn, Jeremy P.; Cliffel, David E.

2010-01-01

330

THERMAL AND ELECTROCHEMICAL THREE DIMENSIONAL CFD MODEL OF A PLANAR SOLID OXIDE ELECTROLYSIS CELL  

SciTech Connect

A three-dimensional computational fluid dynamics (CFD) model has been created to model high-temperature steam electrolysis in a planar solid oxide electrolysis cell (SOEC). The model represents a single cell, as it would exist in an electrolysis stack. Details of the model geometry are specific to a stack that was fabricated by Ceramatec , Inc. and tested at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT2. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean model results are shown to compare favorably with experimental results obtained from an actual ten-cell stack tested at INL.

Grant Hawkes; Jim O'Brien; Carl Stoots; Steve Herring; Mehrdad Shahnam

2005-07-01

331

Rapid Reactivation of Extralymphoid CD4 T Cells during Secondary Infection  

PubMed Central

After infection, extralymphoid tissues are enriched with effector and memory T cells of a highly activated phenotype. The capacity for rapid effector cytokine response from extralymphoid tissue-memory T cells suggests these cells may perform a ‘sentinel’ function in the tissue. While it has been demonstrated that extralymphoid CD4+ T cells can directly respond to secondary infection, little is known about how rapidly this response is initiated, and how early activation of T cells in the tissue may affect the innate response to infection. Here we use a mouse model of secondary heterosubtypic influenza infection to show that CD4+ T cells in the lung airways are reactivated within 24 hours of secondary challenge. Airway CD4+ T cells initiate an inflammatory cytokine and chemokine program that both alters the composition of the early innate response and contributes to the reduction of viral titers in the lung. These results show that, unlike a primary infection, extralymphoid tissue-memory CD4+ T cells respond alongside the innate response during secondary infection, thereby shaping the overall immune profile in the airways. These data provide new insights into the role of extralymphoid CD4+ T cells during secondary immune responses.

Chapman, Timothy J.; Lambert, Kris; Topham, David J.

2011-01-01

332

In-situ Photoelectron Microspectroscopy and Imaging of Electrochemical Processes at the Electrodes of a Self-driven Cell  

PubMed Central

The challenges in development of solid oxide fuel cells (SOFCs) are reducing their dimensions and increasing their efficiency and durability, which requires physicochemical characterization at micro-scales of the device components during operation conditions. Recently, the unique potential of scanning photoelectron microscopy (SPEM) has been demonstrated by in-situ studies of externally-driven SOFCs, which mimic real devices. Here we overcome the gap between model and real systems using a single-chamber Ni|YSZ|Mn SOFC, supporting a range of self-driven electrochemical reactions in variable gas environments and temperatures. The reported SPEM results, obtained during spontaneous electrochemical processes occurring in reactive gas ambient, demonstrate the chemical evolution of electrodic material, in particular the lateral distribution of the oxidation state and the induced local potential, clearly marking out the electrochemically most active micro-regions of the Ni anode.

Bozzini, Benedetto; Amati, Matteo; Gregoratti, Luca; Kiskinova, Maya

2013-01-01

333

In-situ Photoelectron Microspectroscopy and Imaging of Electrochemical Processes at the Electrodes of a Self-driven Cell.  

PubMed

The challenges in development of solid oxide fuel cells (SOFCs) are reducing their dimensions and increasing their efficiency and durability, which requires physicochemical characterization at micro-scales of the device components during operation conditions. Recently, the unique potential of scanning photoelectron microscopy (SPEM) has been demonstrated by in-situ studies of externally-driven SOFCs, which mimic real devices. Here we overcome the gap between model and real systems using a single-chamber Ni|YSZ|Mn SOFC, supporting a range of self-driven electrochemical reactions in variable gas environments and temperatures. The reported SPEM results, obtained during spontaneous electrochemical processes occurring in reactive gas ambient, demonstrate the chemical evolution of electrodic material, in particular the lateral distribution of the oxidation state and the induced local potential, clearly marking out the electrochemically most active micro-regions of the Ni anode. PMID:24092014

Bozzini, Benedetto; Amati, Matteo; Gregoratti, Luca; Kiskinova, Maya

2013-10-04

334

In-situ Photoelectron Microspectroscopy and Imaging of Electrochemical Processes at the Electrodes of a Self-driven Cell  

NASA Astrophysics Data System (ADS)

The challenges in development of solid oxide fuel cells (SOFCs) are reducing their dimensions and increasing their efficiency and durability, which requires physicochemical characterization at micro-scales of the device components during operation conditions. Recently, the unique potential of scanning photoelectron microscopy (SPEM) has been demonstrated by in-situ studies of externally-driven SOFCs, which mimic real devices. Here we overcome the gap between model and real systems using a single-chamber Ni|YSZ|Mn SOFC, supporting a range of self-driven electrochemical reactions in variable gas environments and temperatures. The reported SPEM results, obtained during spontaneous electrochemical processes occurring in reactive gas ambient, demonstrate the chemical evolution of electrodic material, in particular the lateral distribution of the oxidation state and the induced local potential, clearly marking out the electrochemically most active micro-regions of the Ni anode.

Bozzini, Benedetto; Amati, Matteo; Gregoratti, Luca; Kiskinova, Maya

2013-10-01

335

Membraneless microfluidic microbial fuel cell for rapid detection of electrochemical activity of microorganism.  

PubMed

A membraneless microfluidic microbial fuel cell (?MFC) for rapid detection of microorganism electroactivity is demonstrated in this study. Owing to the merit of laminar flow, the proposed ?MFC has well-separated anode and cathode without applying proton exchange membrane. The highest open circuit voltages (OCVs) produced by different anodal solutions: fresh medium, inactivated and untreated microflora, were 102, 131, and 246mV, respectively. These results show that the membraneless ?MFC is capable of identifying the electric potential resulting from the imbalanced compositions between two streams (29mV) and from the electrochemical activity of microflora (115mV). When samples obtained along a batch cycle of H-type MFC were tested, the membraneless ?MFC produced similar OCVs with those from the H-type MFC. In conclusion, the proposed ?MFC has comparable abilities in detecting electroactivity with the conventional H-type MFC; moreover, it can distinguish the source of collected electricity. PMID:23415944

Wang, Hsiang-Yu; Su, Jian-Yu

2013-01-26

336

Thermodynamic relation between voltage-concentration dependence and salt adsorption in electrochemical cells.  

PubMed

Electrochemical cells containing two electrodes dipped in an ionic solution are widely used as charge accumulators, either with polarizable (supercapacitor) or nonpolarizable (battery) electrodes. Recent applications include desalination ("capacitive deionization") and energy extraction from salinity differences ("capacitive mixing"). In this Letter, we analyze a general relation between the variation of the electric potential as a function of the concentration and the salt adsorption. This relation comes from the evaluation of the electrical and mechanical energy exchange along a reversible cycle, which involves salt adsorption and release by the electrodes. The obtained relation thus describes a connection between capacitive deionization and capacitive mixing. We check this relation with experimental data already reported in the literature, and moreover by some classical physical models for electrodes, including polarizable and nonpolarizable electrodes. The generality of the relation makes it very useful in the study of the properties of the electric double layer. PMID:23102339

Rica, R A; Ziano, R; Salerno, D; Mantegazza, F; Brogioli, D

2012-10-11

337

Topographical and chemical effects of electrochemically assisted deposited hydroxyapatite coatings on osteoblast-like cells.  

PubMed

A recently commercialised hydroxyapatite electrochemically assisted chemical deposition technique (BoneMaster) has been shown to induce increased bone apposition; whether this response is caused by the surface topography or chemistry is unknown. An in-vitro examination using human osteoblast-like cells was performed on a series of BoneMaster-coated surfaces. The chemistry was separated from the topography using a thin gold coating; Thermanox coverslips were used as a control. BoneMaster surfaces showed significantly greater alkaline phosphatase activity and osteocalcin production compared with controls; however, no difference was found between the gold-coated and uncoated BoneMaster samples, indicating topography is the main contributing factor. PMID:23680819

Pegg, Elise C; Matboli, Faisal; Marriott, Tim; Khan, Imran; Scotchford, Colin A

2013-05-15

338

ELECTROCHEMICAL SYNTHESIS OF 2,2-DINITROPROPANOL  

SciTech Connect

This paper describes electrochemical approaches to the synthesis of 2,2-dinitropropanol (DNPOH) and discusses the potential for pilot-plant scale synthesis. In this work, the anode of the electrochemical cell replaces the chemical oxidizers used in the conventional synthesis for the purpose of reducing secondary waste and the consequent disposal cost. The electrosynthesis reactions described in this work use the common starting material, nitroethane (NE). The synthesis of the end-product DNPOH involves two steps: 1) electrochemical oxidative nitration (addition of a geminal NO2 group); and, 2) condensation with formaldehyde. Electrochemical oxidation of NE was first attempted by direct oxidation on a Pt electrode surface resulting in low yield and significant generation of undesirable by-product. Alternatively, two different mediators were employed resulting in a dramatic improvement of yield for the oxidative nitration step. The two different mediators used, Ag+/Ag0 and Fe(CN)6-3/-4, were derived from the chemical oxidizers known to perform the oxidative nitration. The Fe(CN)6-3/-4 mediator demonstrated the best promise for scale-up and industrial production due to the lower cost of the mediator and the solubility of the mediator lending it to greater ease-of-use in conventional electrochemical cell designs.

Robert V. Fox

2008-04-01

339

Towards manipulation of post-biosynthetic events in secondary metabolism of plant cell cultures  

Microsoft Academic Search

Plant cell cultures have been suggested as a feasible technology for the production of a myriad of plant-derived metabolites. However, commercial application of plant cell culture has met limited success with only a handful of metabolites produced at the pilot- and commercial-scales. To improve the production of secondary metabolites in plant cell cultures, efforts have been devoted predominantly to the

Wei Zhang; Chris Curtin; Chris Franco

2002-01-01

340

Secondary malignant giant-cell tumor of bone. Clinicopathological assessment of nineteen patients  

SciTech Connect

Twenty-six patients who had a malignant giant-cell tumor of bone--a sarcoma either juxtaposed to a zone of typical benign giant-cell tumor or occurring at the site of a previously documented benign giant-cell tumor--have been seen at the Mayo Clinic. Of the twenty-six tumors, nineteen were secondary to a previous attempt at local control of a benign giant-cell tumor. All but one of these nineteen patients with a secondary tumor had received therapeutic irradiation four to thirty-nine years earlier. The nature and duration of the symptoms and the sites of predilection of the malignant giant-cell tumors were the same as for benign giant-cell tumor. Fibrosarcoma occurred three times as frequently as osteosarcoma. The best results of treatment of the secondary sarcoma were obtained with early ablation.

Rock, M.G.; Sim, F.H.; Unni, K.K.; Witrak, G.A.; Frassica, F.J.; Schray, M.F.; Beabout, J.W.; Dahlin, D.C.

1986-09-01

341

B-Cell Responses During Primary and Secondary Dengue Virus Infections in Humans  

PubMed Central

Low-avidity serotype–cross-reactive antibodies are hypothesized to play a key role in triggering severe disease in patients with secondary dengue virus (DENV) infection. However, there is little systematic information about the frequency, avidity, and cross-reactivity of DENV-specific B cells in individuals experiencing primary instead of secondary infection. We compared DENV-specific B-cell responses in a cohort of Thai children with primary or secondary DENV infection. B cells specific for DENV precursor membrane protein, envelope (E) protein, and nonstructural protein 1 were detectable in immune peripheral blood mononuclear cells with the highest frequencies of DENV E-specific B cells detected in patients experiencing primary DENV-1 infections. DENV E-specific B cells were highly serotype-specific after primary DENV infections, whereas most E-specific B cells in patients with secondary infection were serotype–cross-reactive and secreted antibodies with higher avidity to heterologous DENV serotypes. Our data suggest that the minor populations of serotype–cross-reactive B cells generated by primary DENV infection are preferentially expanded during secondary DENV infection.

West, Kim; Kalayanarooj, Siripen; Gibbons, Robert V.; Srikiatkhachorn, Anon; Green, Sharone; Libraty, Daniel; Jaiswal, Smita; Rothman, Alan L.

2011-01-01

342

Identification of transcription factors involved in rice secondary cell wall formation.  

PubMed

Using co-expression network analysis, we identified 123 transcription factors (TFs) as candidate secondary cell wall regulators in rice. To validate whether these TFs are associated with secondary cell wall formation, six TF genes belonging to the MYB, NAC or homeodomain-containing TF families were overexpressed or downregulated in rice. With the exception of OsMYB58/63-RNAi plants, all transgenic plants showed phenotypes possibly related to secondary cell wall alteration, such as dwarfism, narrow and dark green leaves, and also altered rice cinnamyl alcohol dehydrogenase 2 (OsCAD2) gene expression and lignin content. These results suggest that many of the 123 candidate secondary cell wall-regulating TFs are likely to function in secondary cell wall formation in rice. Further analyses were performed for the OsMYB55/61 and OsBLH6 TFs, the former being a TF in which the Arabidopsis ortholog is known to participate in lignin biosynthesis (AtMYB61) and the latter being one for which no previous involvement in cell wall formation has been reported even in Arabidopsis (BLH6). OsMYB55/61 and OsBLH6-GFP fusion proteins localized to the nucleus of onion epidermal cells. Moreover, expression of a reporter gene driven by the OsCAD2 promoter was enhanced in rice calli when OsMYB55/61 or OsBLH6 was transiently expressed, demonstrating that they function in secondary cell wall formation. These results show the validity of identifying potential secondary cell wall TFs in rice by the use of rice co-expression network analysis. PMID:24089432

Hirano, Ko; Kondo, Mari; Aya, Koichiro; Miyao, Akio; Sato, Yutaka; Antonio, Baltazar A; Namiki, Nobukazu; Nagamura, Yoshiaki; Matsuoka, Makoto

2013-10-01

343

Junction studies on electrochemically fabricated p-n Cu(2)O homojunction solar cells for efficiency enhancement.  

PubMed

p-n Cu(2)O homojunction solar cells were electrochemically fabricated by consecutively depositing an n-Cu(2)O layer on a p-Cu(2)O layer. In order to better understand the Fermi levels of the electrochemically grown polycrystalline p- and n-Cu(2)O layers and maximize the overall cell performance, the back and front contacts of the Cu(2)O homojunction cells were systematically changed and the I-V characteristics of the resulting cells were examined. The result shows that the intrinsic doping levels of the electrochemically prepared p-Cu(2)O and n-Cu(2)O layers are very low and they made almost Ohmic junctions with Cu metal with which previously studied p-Cu(2)O layers prepared by thermal oxidation of Cu foils are known to form Schottky junctions. The best cell performance (an ? of 1.06%, a V(OC) of 0.621 V, an I(SC) of 4.07 mA cm(-2), and a fill factor (ff) of 42%) was obtained when the p-Cu(2)O layer was deposited on a commercially available ITO substrate as the back contact and a sputter deposited ITO layer was used as the front contact on the n-Cu(2)O layer. The unique features of the p-n Cu(2)O homojunction solar cell are discussed in comparison with other Cu(2)O-based heterojunction solar cells. PMID:22446958

McShane, Colleen M; Choi, Kyoung-Shin

2012-03-23

344

The electrochemical intercalation of Li into graphite in Li/polymer electrolyte/graphite cells  

SciTech Connect

The electrochemical intercalation of Li into graphite has been studied in Li/polymer electrolyte/graphite cells using an in situ X-ray diffraction (XRD) technique. In cells containing an electrolyte of PAN (polyacrylonitrile)-EC (ethylene carbonate)-LiPF{sub 6}, a minor irreversible reduction of the electrolyte is observed only during the first discharge. In these cells, Li is reversibly intercalated into graphite to form Li{sub 1.0}C{sub 6}, principally at potentials between 0.2 and 0.0 V vs. Li{sup +}/Li. No evidence for the cointercalation of EC was obtained. In cells containing PAN-EC/PC(propylene carbonate)-LiPF{sub 6}-based electrolyte, a massive reduction of electrolyte occurs during the first discharge at {approximately}0.8 V vs. Li{sup +}/Li, which precludes Li intercalation into graphite. In situ XRD data are consistent with the absence of the intercalation of PC or Li{sup +}(PC){sub n} solvates into the graphite lattice, either prior to or during the solvent reduction process. The latter appears to be a surface-catalyzed process, the extent of which is determined by a combination of thermodynamic and kinetic factors including the reduction potential of the electrolyte, and the passivating films which form on the graphite surface as a result of electrolyte reduction.

Jiang, Z.; Alamgir, M.; Abraham, K.M. [EIC Labs., Inc., Norwood, MA (United States)

1995-02-01

345

In vitro electrochemical detection of wheat allergen using rat basophilic leukaemia (RBL-1) cells.  

PubMed

We have investigated an electrochemical method of detecting foods that cause an allergic reaction. Rat basophilic leukaemia (RBL-1) cells were sensitized with serum from a rat that was allergic to wheat. A sample containing the protein fraction of a food was added to the cells and incubated. The cells were immobilized on a membrane filter and attached to a basal-plane pyrolytic graphite electrode. When a potential was applied in the range 0-1.0 V relative to a saturated calomel electrode, an anodic peak current appeared at around 0.33 V. This peak current, attributed to serotonin, increased with time, and the maximum current (0.5 microA) was obtained 20-25 min of incubation. The response of the RBL-1 cells was specific to the protein fraction of wheat. The peak current increased linearly with increasing protein concentration in the range of 0.01-0.5 micrograms ml-1. These results suggest that the concentration of the protein bringing about the allergic reaction can be determined by cyclic voltammetry within 25 min. This method is more sensitive than the conventional skin tests. PMID:7546602

Nakamura, N; Kumazawa, S; Matsunaga, T

346

Highly sensitive recognition of cancer cells by electrochemical biosensor based on the interface of gold nanoparticles\\/polylactide nanocomposites  

Microsoft Academic Search

The efficient diagnosis and therapy of cancers have been the hot topics in the clinic and biomedical areas. In this study, we have developed a new strategy for the fast and high sensitive recognition of the drug-sensitive leukemia K562\\/B.W. cells and drug-resistant leukemia K562\\/ADM cells by combining the nanocomposites interface of the gold nanoparticles\\/polylactide nanofibers (Au\\/PLA) with the electrochemical detection.

Xiaojing Wu; Hui Jiang; Jiusong Zheng; Xuemei Wang; Zhongze Gu; Chen Chen

2011-01-01

347

An advanced lithium-aluminum\\/iron disulfide secondary cell  

Microsoft Academic Search

An advanced Li-Al\\/FeS2 cell is described in which the dense U.P.-FeS2 electrode has replaced the T.P.-FeS2 of the earlier cells of this type, and the lower-melting LiCl-LiBr-KBr electrolyte has replaced LiCl-KCl electrolyte. The results of cycle-life testing (at 397) of the Li-Al\\/LiCl-LiBr-KBr\\/U.P.-FeS2 cell have shown that this cell has at least 50 percent higher energy density than a Li-Al\\/LiCl-KCl\\/T.P.-FeS2 cell

Thomas D. Kaun

1986-01-01

348

Design, evaluation, and application of continuous-flow cells for organic electrochemical synthesis. Final report  

SciTech Connect

Two examples of the oxidation and reduction of aldehydes as a paired synthesis have been studied. These are model systems for potential energy savings in organic electrochemical synthesis. Both are indirect processes; the reduction via alkali metal amalgam and the oxidation via hypobromite. One, using furfural as the substrate, has proved unsuccessful due to the oxidation of its reduction products with the electrogenerated oxidant, bromine. The other paired synthesis, using glucose, has been operated successfully in two types of parallel plate flow cells and two types of porous, packed bed flow cells. To date, the optimum electrode materials and operating conditions for the glucose paired reaction, as determined by product yields and current efficiencies, are an amalgamated zinc cathode, a graphite anode, an initial glucose concentration of 0.8M, a 0.8M NaBr supporting electrolyte and an electrolyte flow rate of 0.8 1/min. Both constant current (10 mA/cm/sup 2/) and constant cathode potential (-2.10V vs SCE) electrolyses were performed under the above conditions. Electrolyses carried out in the parallel plate flow cell and the packed bed flow cell in which the current and electrolyte flow are parallel to one another gave comparable results. Lower current efficiencies were obtained in the porous, packed bed flow cell with perpendicular current and flow. The reasons for the poorer results in the perpendicular configuration cell are not known at this time and further experimentation is required with this system. The current efficiencies and yields of both the oxidation reaction (the production of gluconic acid) and the reduction reaction (the formation of sorbitol) in the packed bed cells were found to be dependent on solution pH.

Nobe, K.

1982-09-30

349

Distinct CD4+ helper T cells involved in primary and secondary responses to infection  

PubMed Central

Helper T cells are critical for protective immunity, CD8+ T-cell memory, and CD4+ recall responses, but whether the same or distinct CD4+ T cells are involved in these responses has not been established. Here we describe two CD4+ T cells, LLO118 and LLO56, specific for an immunodominant Listeria monocytogenes epitope, with dramatically different responses to primary and secondary infection. Comparing in vivo responses, LLO118 T cells proliferate more strongly to primary infection, whereas surprisingly, LLO56 has a superior CD4+ recall response to secondary infection. LLO118 T cells provide more robust help for CD8+ T-cell responses to secondary infection than LLO56. We found no detectable differences in antigen sensitivity, but naive LLO118 T cells have much lower levels of CD5 and their T-cell receptor levels are dramatically down-regulated after their strong primary response. Thus, distinct CD4+ helper T cells are specialized to help either in primary or secondary responses to infection.

Weber, K. Scott; Li, Qi-Jing; Persaud, Stephen P.; Campbell, Jeff D.; Davis, Mark M.; Allen, Paul M.

2012-01-01

350

A sodium/beta-alumina/nickel chloride secondary cell  

NASA Astrophysics Data System (ADS)

Nickel chloride has been studied in a cell system, sodium/beta alumina/sodium tetrachloroaluminate/nickel chloride, which is analogous to two existing rechargeable high energy density cells based on iron chloride and sodium sulfur. The cell reaction can be written as: 2Na + NiCl2 yields on discharge Ni + 2NaCl. The positive electrode, conveniently assembled in the discharged state, was a nickel/sodium choride sinter. Molten sodium tetrachloroaluminate electrolyte (NaAlCl4) acted as intermediate between electrode and beta alumina tube. Encouraging results were obtained in terms of low resistances and rates of discharge for cells up to 20-Ah capacity. Cells were operated over the temperature range from 230 to 400 C where the OCV of the cell reaction varied from 2.60 V to 2.56 V.

Galloway, R. C.

1987-01-01

351

Comparison of mesenchymal stem cell proliferation and differentiation between biomimetic and electrochemical coatings on different topographic surfaces.  

PubMed

The hypothesis for this study was that there is no difference in mesenchymal stem cells (MSCs) proliferation and osteogenic differentiation between calcium-phosphate (CaP) coatings with different crystal size deposited on different topographic surfaces of metal discs. Polished (P) and sand-blasted (SB) tantalum and TiAl6V4 discs were CaP coated by three methods-biomimetic (BioM), electrochemical at 20 mA/cm(2) and at 6.5 mA/cm(2)-and cultured with MSCs. At days 4, 7 and 14, cell proliferation-alamarBlue(®) activity and DNA quantification-and differentiation down the osteogenic lineage-ALP activity normalised per amount of DNA and SEM (morphology)-were analysed. Results showed that MSCs proliferated more when cultured on the nano-sized BioM coatings compared to uncoated and electrochemically coated discs. MSCs also proliferated more on P surfaces than on SB and or electrochemical coatings. All the coatings induced osteogenic differentiation, which was greater on electrochemical coatings and SB discs. PMID:23053816

García-Gareta, Elena; Hua, Jia; Knowles, Jonathan C; Blunn, Gordon W

2012-10-10

352

A sodium\\/beta-alumina\\/nickel chloride secondary cell  

Microsoft Academic Search

Nickel chloride has been studied in a cell system, sodium\\/beta alumina\\/sodium tetrachloroaluminate\\/nickel chloride, which is analogous to two existing rechargeable high energy density cells based on iron chloride and sodium sulfur. The cell reaction can be written as: 2Na + NiCl2 yields on discharge Ni + 2NaCl. The positive electrode, conveniently assembled in the discharged state, was a nickel\\/sodium choride

R. C. Galloway

1987-01-01

353

Multichannel bipotentiostat integrated with a microfluidic platform for electrochemical real-time monitoring of cell cultures.  

PubMed

An electrochemical detection system specifically designed for multi-parameter real-time monitoring of stem cell culturing/differentiation in a microfluidic system is presented. It is composed of a very compact 24-channel electronic board, compatible with arrays of microelectrodes and coupled to a microfluidic cell culture system. A versatile data acquisition software enables performing amperometry, cyclic voltammetry and impedance spectroscopy in each of the 12 independent chambers over a 100 kHz bandwidth with current resolution down to 5 pA for 100 ms measuring time. The design of the platform, its realization and experimental characterization are reported, with emphasis on the analysis of impact of input capacitance (i.e., microelectrode size) and microfluidic pump operation on current noise. Programmable sequences of successive injections of analytes (ferricyanide and dopamine) and rinsing buffer solution as well as the impedimetric continuous tracking for seven days of the proliferation of a colony of PC12 cells are successfully demonstrated. PMID:23853236

Vergani, Marco; Carminati, Marco; Ferrari, Giorgio; Landini, Ettore; Caviglia, Claudia; Heiskanen, Arto; Comminges, Clément; Zór, Kinga; Sabourin, David; Dufva, Martin; Dimaki, Maria; Raiteri, Roberto; Wollenberger, Ulla; Emneus, Jenny; Sampietro, Marco

2012-10-01

354

In situ fluorescence and electrochemical monitoring of a photosynthetic microbial fuel cell.  

PubMed

Using an in-house developed platform, the performance of an Arthrospira maxima biofilm photosynthetic microbial fuel cell (PMFC) was monitored both optically and electrochemically. Fluorescence (excitation wavelength 633 nm, emission range 640 to 800 nm for detection of fluorescence), power density and current output of the PMFC were recorded in real time. Confocal microscopy performed in situ allowed detailed fluorescence imaging to further improve the understanding of the photosynthetic activity of the biofilm that developed on the anode surface of the PMFC, whilst power and current outputs indicated the performance of the cell. The PMFC was shown to be sensitive to temperature and light perturbations with increased temperatures and light intensities resulting in improved performance. A direct relationship between the fluorescent signature and the amount of current produced was identified. With a decreasing external load and increasing current production, the biofilm attached to the anode electrode showed increased fluorescence inferring improved activity of the photosynthetic material. Furthermore, the imaging proved that viable cells covered the entire surface area of the biofilm and that the fluorescence increased with increasing distance (z axis) from the electrode surface. PMID:23549224

Inglesby, Alister E; Yunus, Kamran; Fisher, Adrian C

2013-04-02

355

Hermetically sealed button-type electrochemical cell and method for making same  

SciTech Connect

An ultra-thin hermetically sealed button-type electrochemical cell is disclosed comprising a pair of mating metallic housing members, at least one of which is generally dish shaped to define an enclosed space therebetween. A peripheral opening defining a fill port is formed in one of the housing members, preferably at the junction formed by the mating surfaces. The interfacing surfaces of the cell housing members are welded together subsequent to the insertion of the internal cell components and prior to the addition of the electrolyte to form a hermetic seal. The electrolyte may then be added and the fill port hermetically sealed by welding. Owing to its relatively small size, the fill port may be quickly sealed so that the heat generated during the weld process is insufficient to volatilize the electrolyte. One of the housing members has a facial hole containing a glass-tometal seal through which an electrically conductive metal terminal structure extends and located such that the heat of welding may be dissipated by the housing members without adversely affecting the glass-to-metal seal.

Epstein, J.; Marincic, N.

1980-01-08

356

A thin layer electrochemical cell for disinfection of water contaminated with Staphylococcus aureus  

PubMed Central

A thin layer electrochemical cell was tested and developed for disinfection treatment of water artificially contaminated with Staphylococcus aureus. Electrolysis was performed with a low-voltage DC power source applying current densities of 75 mA cm-2 (3 A) or 25 mA cm-2 (1 A). A dimensionally stable anode (DSA) of titanium coated with an oxide layer of 70%TiO2 plus 30%RuO2 (w/w) and a 3 mm from a stainless-steel 304 cathode was used in the thin layer cell. The experiments were carried out using a bacteria suspension containing 0.08 M sodium sulphate with chloride-free to determine the bacterial inactivation efficacy of the thin layer cell without the generation of chlorine. The chlorine can promote the formation of trihalomethanes (THM) that are carcinogenic. S. aureus inactivation increased with electrolysis time and lower flow rate. The flow rates used were 200 or 500 L h-1. At 500 L h-1 and 75 mA cm-2 the inactivation after 60 min was about three logs of decreasing for colony forming units by mL. However, 100% inactivation for S. aureus was observed at 5.6 V and 75 mA cm-2 after 30 min. Thus, significant disinfection levels can be achieved without adding oxidant substances or generation of chlorine in the water.

Gusmao, Isabel C. P.; Moraes, Peterson B.; Bidoia, Ederio D.

2009-01-01

357

Effects of Operating Conditions on Internal Resistances in Enzyme Fuel Cells Studied via Electrochemical Impedance Spectroscopy  

SciTech Connect

Enzyme fuel cells (EFCs) offer some advantages over traditional precious-metal-catalyzed fuel cells, such as polymer electrolyte membrane fuel cells (PEMFCs). However, EFCs exhibit far less power output than PEMFCs and have relatively short life spans before materials must be replaced. In this work, electrochemical impedance spectroscopy (EIS) is used to analyze the internal resistances throughout the EFC at a variety of operating conditions. EIS analysis is focused primarily on the resistances of the anode, solution/membrane, and cathode. Increased enzyme loading results in improved power output and reductions in internal resistance. Conditions are identified for which enzyme loading does not limit the EFC performance. EIS experiments are also reported for EFCs operated continuously for 2 days; power output declines sharply over time, while all internal resistances increase. Drying of the cathode and enzyme/mediator degradation are believed to have contributed to this behavior. Finally, experiments are performed at varying air-humidification temperatures. Little effect on internal resistances or power output is observed. However, it is anticipated that increased air humidification can improve longevity by delivering more water to the cathode. Improvements to the enzymatic cathode are needed for EFC development. These improvements need to focus on improving transport rather than increasing enzyme loading.

Aaron, D [Georgia Institute of Technology; Borole, Abhijeet P [ORNL; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

2012-01-01

358

Microbial Communities and Electrochemical Performance of Titanium-Based Anodic Electrodes in a Microbial Fuel Cell?  

PubMed Central

Four types of titanium (Ti)-based electrodes were tested in the same microbial fuel cell (MFC) anodic compartment. Their electrochemical performances and the dominant microbial communities of the electrode biofilms were compared. The electrodes were identical in shape, macroscopic surface area, and core material but differed in either surface coating (Pt- or Ta-coated metal composites) or surface texture (smooth or rough). The MFC was inoculated with electrochemically active, neutrophilic microorganisms that had been enriched in the anodic compartments of acetate-fed MFCs over a period of 4 years. The original inoculum consisted of bioreactor sludge samples amended with Geobacter sulfurreducens strain PCA. Overall, the Pt- and Ta-coated Ti bioanodes (electrode-biofilm association) showed higher current production than the uncoated Ti bioanodes. Analyses of extracted DNA of the anodic liquid and the Pt- and Ta-coated Ti electrode biofilms indicated differences in the dominant bacterial communities. Biofilm formation on the uncoated electrodes was poor and insufficient for further analyses. Bioanode samples from the Pt- and Ta-coated Ti electrodes incubated with Fe(III) and acetate showed several Fe(III)-reducing bacteria, of which selected species were dominant, on the surface of the electrodes. In contrast, nitrate-enriched samples showed less diversity, and the enriched strains were not dominant on the electrode surface. Isolated Fe(III)-reducing strains were phylogenetically related, but not all identical, to Geobacter sulfurreducens strain PCA. Other bacterial species were also detected in the system, such as a Propionicimonas-related species that was dominant in the anodic liquid and Pseudomonas-, Clostridium-, Desulfovibrio-, Azospira-, and Aeromonas-related species.

Michaelidou, Urania; ter Heijne, Annemiek; Euverink, Gerrit Jan W.; Hamelers, Hubertus V. M.; Stams, Alfons J. M.; Geelhoed, Jeanine S.

2011-01-01

359

Electrochemical characterization of nano-sized Pd-based catalysts as cathode materials in direct methanol fuel cells.  

PubMed

To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd-TiO2) catalysts which the Pd and TiO2 nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO2 as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO2 on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd-TiO2/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd-TiO2 catalysts were strongly influenced by the TiO2 content. In the single cell test, the Pd-TiO2 catalysts showed very comparable performance to the Pt catalyst. PMID:21446535

Choi, M; Han, C; Kim, I T; An, J C; Lee, J J; Lee, H K; Shim, J

2011-01-01

360

Hermetically Sealed Electrical Feedthrough for High Temperature Secondary Cells.  

National Technical Information Service (NTIS)

A passthrough seal is disclosed for electrically isolating the terminal in a lithium/metal sulfide cell from the structural cell housing. The seal has spaced upper and lower insulator rings fitted snuggly between the terminal and an annularly disposed ups...

R. Knoedler P. A. Nelson H. Shimotake J. E. Battles

1983-01-01

361

Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation  

PubMed Central

Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

2013-01-01

362

Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation.  

PubMed

Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. PMID:24098302

Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

2013-10-01

363

Circulating cells as predictors of secondary manifestations of cardiovascular disease: design of the CIRCULATING CELLS study.  

PubMed

Biomarkers for primary or secondary risk prediction of cardiovascular disease (CVD) are urgently needed to improve individual treatment and clinical trial design. The vast majority of biomarker discovery studies has concentrated on plasma/serum as an easily accessible source. Although numerous markers have been identified, their added predictive value on top of traditional risk factors has been limited, as the biological specimen does not specifically reflect expression profiles related with CVD progression and because the signal is often diluted by marker release from other organs. In contrast to serum markers, circulating cells serve as indicators of the actual disease state due to their active role in the pathogenesis of CVD and are responsible for the majority of secreted biomarkers. Therefore, the CIRCULATING CELLS study was initiated, focusing on the cellular effectors of atherosclerosis in the circulation. In total, 714 patients with coronary artery disease (CAD) symptoms were included. Blood cell fractions (monocytes, T-lymphocytes, platelets, granulocytes, PBMC) of all individual patients were isolated and stored for analysis. Concomitantly, extensive flow cytometric characterization of these populations was performed. From each patient, a detailed clinical profile together with extensive questionnaires about medical history and life style was obtained. Various high-throughput -omics approaches (protein, mRNA, miRNA) are currently being undertaken. Data will be integrated with advanced bioinformatics for discovery and validation of secondary risk markers for adverse events. Overall, the CIRCULATING CELLS study grants the interesting possibility that it will both identify novel biomarkers and provide useful insights into the pathophysiology of CAD in patients. PMID:23975238

Hoefer, Imo E; Sels, Jan-Willem; Jukema, J Wouter; Bergheanu, Sandrin; Biessen, Erik; McClellan, Elizabeth; Daemen, Mat; Doevendans, Pieter; de Groot, Philip; Hillaert, Marieke; Horsman, Sebastiaan; Ilhan, Mustafa; Kuiper, Johan; Pijls, Nico; Redekop, Ken; van der Spek, Peter; Stubbs, Andrew; van de Veer, Eric; Waltenberger, Johannes; van Zonneveld, Anton-Jan; Pasterkamp, Gerard

2013-08-23

364

Neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues  

SciTech Connect

Antigen-transporting cells take up pathogens, and then migrate from sites of inflammation to secondary lymphoid tissues to induce an immune response. Among antigen-transporting cells, dendritic cells (DCs) are believed to be the most potent and professional antigen-presenting cells that can stimulate naive T cells. However, the cells that transport antigens, tumor cell antigens in particular, have not been clearly identified. In this study we have analyzed what types of cells transport tumor cell antigens to secondary lymphoid tissues. We show that neutrophils, monocytes and macrophages but not DCs engulf X-irradiated P388 leukemic cells after their injection into the peritoneal cavity, and that neutrophils and monocytes but not macrophages migrate to the parathymic lymph nodes (pLN), the blood, and then the spleen. The monocytes in the pLN comprise Gr-1{sup -} and Gr-1{sup +} ones, and some of these cells express CD11c. Overall, this study demonstrates that neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues.

Terasawa, Masao; Nagata, Kisaburo [Division of Molecular Medicine, Department of Biomolecular Science, Faculty of Science, Toho University, 2-2-1, Miyama, Funabashi (Japan); Kobayashi, Yoshiro [Division of Molecular Medicine, Department of Biomolecular Science, Faculty of Science, Toho University, 2-2-1, Miyama, Funabashi (Japan)], E-mail: yoshiro@biomol.sci.toho-u.ac.jp

2008-12-12

365

The current distribution and shape change of zinc electrodes in secondary silver-zinc cells  

Microsoft Academic Search

The current and potential distributions of zinc electrodes in secondary zinc-silver oxide cells during cycling were studied using a sectioned electrode technique. The shape change occurring in zinc electrodes resulting from cell cycling was examined. The zinc electrodes used for this study were of a conventional type of design and were fabricated by a slurry paste method. The positive electrodes

S.-P. Poa; C. H. Wu

1978-01-01

366

Electrochemical detection of catecholamine release using planar iridium oxide electrodes in nanoliter microfluidic cell culture volumes.  

PubMed

Release of neurotransmitters and hormones by calcium regulated exocytosis is a fundamental cellular/molecular process that is disrupted in a variety of psychiatric, neurological, and endocrine disorders. Therefore, this area represents a relevant target for drug and therapeutic development, efforts that will be aided by novel analytical tools and devices that provide mechanistically rich data with increased throughput. Toward this goal, we have electrochemically deposited iridium oxide (IrOx) films onto planar thin film platinum electrodes (20 ?m×300 ?m) and utilized these for quantitative detection of catecholamine release from adrenal chromaffin cells trapped in a microfluidic network. The IrOx electrodes show a linear response to norepinephrine in the range of 0-400 ?M, with a sensitivity of 23.1±0.5 mA/M mm(2). The sensitivity of the IrOx electrodes does not change in the presence of ascorbic acid, a substance commonly found in biological samples. A replica molded polydimethylsiloxane (PDMS) microfluidic device with nanoliter sensing volumes was aligned and sealed to a glass substrate with the sensing electrodes. Small populations of chromaffin cells were trapped in the microfluidic device and stimulated by rapid perfusion with high potassium (50mM) containing Tyrode's solution at a flow rate of 1 nL/s. Stimulation of the cells produced a rapid increase in current due to oxidation of the released catecholamines, with an estimated maximum concentration in the cell culture volume of ~52 ?M. Thus, we demonstrate the utility of an integrated microfluidic network with IrOx electrodes for real-time quantitative detection of catecholamines released from small populations of chromaffin cells. PMID:22398270

Ges, Igor A; Currie, Kevin P M; Baudenbacher, Franz

2011-12-22

367

A battery of transcription factors involved in the regulation of secondary cell wall biosynthesis in Arabidopsis.  

PubMed

SECONDARY WALL-ASSOCIATED NAC DOMAIN PROTEIN1 (SND1) is a master transcriptional switch activating the developmental program of secondary wall biosynthesis. Here, we demonstrate that a battery of SND1-regulated transcription factors is required for normal secondary wall biosynthesis in Arabidopsis thaliana. The expression of 11 SND1-regulated transcription factors, namely, SND2, SND3, MYB103, MYB85, MYB52, MYB54, MYB69, MYB42, MYB43, MYB20, and KNAT7 (a Knotted1-like homeodomain protein), was developmentally associated with cells undergoing secondary wall thickening. Of these, dominant repression of SND2, SND3, MYB103, MYB85, MYB52, MYB54, and KNAT7 significantly reduced secondary wall thickening in fiber cells. Overexpression of SND2, SND3, and MYB103 increased secondary wall thickening in fibers, and overexpression of MYB85 led to ectopic deposition of lignin in epidermal and cortical cells in stems. Furthermore, SND2, SND3, MYB103, MYB85, MYB52, and MYB54 were able to induce secondary wall biosynthetic genes. Direct target analysis using the estrogen-inducible system revealed that MYB46, SND3, MYB103, and KNAT7 were direct targets of SND1 and also of its close homologs, NST1, NST2, and vessel-specific VND6 and VND7. Together, these results demonstrate that a transcriptional network consisting of SND1 and its downstream targets is involved in regulating secondary wall biosynthesis in fibers and that NST1, NST2, VND6, and VND7 are functional homologs of SND1 that regulate the same downstream targets in different cell types. PMID:18952777

Zhong, Ruiqin; Lee, Chanhui; Zhou, Jianli; McCarthy, Ryan L; Ye, Zheng-Hua

2008-10-24

368

Red cell membrane lipid peroxidation and hemolysis secondary to phototherapy.  

PubMed

The exposure of red cells to phototherapy light in the presence of a sensitizer (bilirubin) resulted in oxidative injury to the red cell membrane as manifested by a significant increase in the concentration of the products of lipid peroxidation (TBA reactants and diene conjugation) in the membrane and hemolysis. To induce a photo-oxidized membrane injury, the sensitizer (bilirubin) has to be membrane bound. Thus, by altering the availability of free bilirubin in the red cell suspension through changes in the molar concentration ratio of bilirubin to albumin, one is able to regulate the occurrence and extent of the oxidative red cell membrane injury. The clinical implications of these findings are discussed. PMID:4003061

Ostrea, E M; Cepeda, E E; Fleury, C A; Balun, J E

1985-05-01

369

BMP7 Expression Correlates with Secondary Drug Resistance in Mantle Cell Lymphoma  

PubMed Central

Purpose We designed a gene profiling experiment to identify genes involved in secondary drug resistance in mantle cell lymphomas (MCL). Experimental Design We obtained paired tissue samples collected from the same patients before treatment and after relapse or progression. Variations in gene expression between the 2 samples were estimated for 5 patients. For each gene, the mean variation was estimated for patients with a refractory primary tumor and for responders who developed secondary drug resistance. Nine genes of interest were selected on the basis of the magnitude and statistical significance of the variation of expression in responders and non-responders. Results BMP7 was the only one with significantly increased expression at relapse in patients who developed secondary resistance. Validation of BMP7 as a key gene involved in secondary resistance was performed using cultures of cell line. Incubation of BMP7 with MCL cell lines increased their resistance to bortezomib and cytarabine, while inhibition of BMP7 expression by siRNA correlated with increased cell death linked to drug application. Conclusion Variations in gene expression after treatment point out BMP7 as a key gene involved in secondary resistance in mantle cell lymphoma.

Roux, Sebastien; Lamy, Thierry; Bosq, Jacques; Bernard, Marc; Fest, Thierry; Lazar, Vladimir; Lenoir, Gilbert; Ribrag, Vincent

2013-01-01

370

Universal transients in polymer and ionic transition metal complex light-emitting electrochemical cells.  

PubMed

Two types of light-emitting electrochemical cells (LECs) are commonly distinguished, the polymer-based LEC (p-LEC) and the ionic transition metal complex-based LEC (iTMC-LEC). Apart from marked differences in the active layer constituents, these LEC types typically show operational time scales that can differ by many orders of magnitude at room temperature. Here, we demonstrate that despite these differences p-LECs and iTMC-LECs show current, light output, and efficacy transients that follow a universal shape. Moreover, we conclude that the turn-on time of both LEC types is dominated by the ion conductivity because the turn-on time exhibits the same activation energy as the ion conductivity in the off-state. These results demonstrate that both types of LECs are really two extremes of one class of electroluminescent devices. They also implicate that no fundamental difference exists between charge transport in small molecular weight or polymeric mixed ionic and electronic conductive materials. Additionally, it follows that the ionic conductivity is responsible for the dynamic properties of devices and systems using them. This likely extends to mixed ionic and electronic conductive materials used in organic solar cells and in a variety of biological systems. PMID:23256637

van Reenen, Stephan; Akatsuka, Takeo; Tordera, Daniel; Kemerink, Martijn; Bolink, Henk J

2013-01-08

371

Measuring fundamental properties in operating solid oxide electrochemical cells by using in situ X-ray photoelectron spectroscopy.  

PubMed

Photoelectron spectroscopic measurements have the potential to provide detailed mechanistic insight by resolving chemical states, electrochemically active regions and local potentials or potential losses in operating solid oxide electrochemical cells (SOCs), such as fuel cells. However, high-vacuum requirements have limited X-ray photoelectron spectroscopy (XPS) analysis of electrochemical cells to ex situ investigations. Using a combination of ambient-pressure XPS and CeO(2-x)/YSZ/Pt single-chamber cells, we carry out in situ spectroscopy to probe oxidation states of all exposed surfaces in operational SOCs at 750 °C in 1 mbar reactant gases H(2) and H(2)O. Kinetic energy shifts of core-level photoelectron spectra provide a direct measure of the local surface potentials and a basis for calculating local overpotentials across exposed interfaces. The mixed ionic/electronic conducting CeO(2-x) electrodes undergo Ce(3+)/Ce(4+) oxidation-reduction changes with applied bias. The simultaneous measurements of local surface Ce oxidation states and electric potentials reveal the active ceria regions during H(2) electro-oxidation and H(2)O electrolysis. The active regions extend ~150 ?m from the current collectors and are not limited by the three-phase-boundary interfaces associated with other SOC materials. The persistence of the Ce(3+)/Ce(4+) shifts in the ~150 ?m active region suggests that the surface reaction kinetics and lateral electron transport on the thin ceria electrodes are co-limiting processes. PMID:20871607

Zhang, Chunjuan; Grass, Michael E; McDaniel, Anthony H; DeCaluwe, Steven C; El Gabaly, Farid; Liu, Zhi; McCarty, Kevin F; Farrow, Roger L; Linne, Mark A; Hussain, Zahid; Jackson, Gregory S; Bluhm, Hendrik; Eichhorn, Bryan W

2010-09-26

372

A novel quantum dot nanocluster as versatile probe for electrochemiluminescence and electrochemical assays of DNA and cancer cells.  

PubMed

A novel dendritic quantum dot (QD) nanocluster was constructed and used as versatile electrochemiluminescence (ECL) and electrochemical probe for the detection of DNA and cancer cells. Owing to the many functional groups present in the nanoclusters, a large number of QDs were assembled on the nanoclusters, which could greatly amplify both the ECL and electrochemical signals of QDs. Carbon nanotubes (CNTs)/gold nanoparticles' (NPs) hybrids were used as amplified platform for assembling large numbers of DNA on the electrode, which also improve the bioactivity and stability of the electrode. After the QD-DNA signal probe was recognized with target DNA (t-DNA), the amplified ECL signal for the detection of target DNA was obtained. Furthermore, magnetic nanoparticles were employed for cell aptamers immobilization, the same QD nanocluster-DNA probe was also extended for electrochemical detection of cancer cells using sensitive anodic stripping voltammetry (ASV) method, which simplified the separation procedures and improved the sensitivity. It is anticipated that the assays could provide promising and cost effective approach for the early and accurate detection of DNA and cancer cells. PMID:24021658

Jie, Guifen; Zhang, Jian; Jie, Guixia; Wang, Lei

2013-08-26

373

Computational, electrochemical and {sup 7}Li NMR studies of lithiated disordered carbons electrodes in lithium ion cells.  

SciTech Connect

Disordered carbons that deliver high reversible capacity in electrochemical cells have been synthesized by using inorganic clays as templates to control the pore size and the surface area. The capacities obtained were much higher than those calculated if the resultant carbon had a graphitic-like structure. Computational chemistry was used to investigate the nature of lithium bonding in a carbon lattice unlike graphite. The lithium intercalated fullerene Li{sub n}-C{sub 60} was used as a model for our (non-graphitic) disordered carbon lattice. A dilithium-C{sub 60} system with a charge and multiplicity of (0,1) and a trilithium-C{sub 60} system with a charge and multiplicity of (0,4) were investigated. The spatial distribution of lithium ions in an electrochemical cell containing this novel disordered carbon material was investigated in situ by Li-7 NMR using an electrochemical cell that was incorporated into a toroid cavity nuclear magnetic resonance (NMR) imager. The concentration of solvated Li{sup +} ions in the carbon anode appears to be larger than in the bulk electrolyte, is substantially lower near the copper/carbon interface, and does not change with cell charging.

Sandi, G.; Gerald, R., II; Scanlon, L. G.; Carrado, K. A.; Winans, R. E.

1998-01-07

374

Comprehensive forensic analyses of debris from the fatal explosion of a "cold fusion" electrochemical cell.  

PubMed

Selected components of explosion debris from the SRI International incident of January 2, 1992 were subjected to forensic analyses to elucidate potential causes of, or contributing factors to, the explosion. Interrogation of the debris encompassed nuclear, chemical, physical, and materials investigations. Nuclear studies for the determination of tritium and neutron-activation products in stainless steel and brass were conducted. No evidence for signature species indicative of orthodox nuclear events was detected. The inorganic and particulate analyses were likewise negative with respect to residues of unexpected chemical species. Such target compounds included conventional explosives, accelerants, propellants, or any exceptional industrial chemicals. Materials characterization identified the type of stainless steel used in the manufacture of the electrolytic cell as one relatively high in Mo concentration, probably type 316. Metallurgical analyses of the cell vessel wall and its detached base provided no evidence of corrosion or hydrogen embrittlement, leaving only ductile failure of the weld as contributing to the incident. The weld was found to have missed the center-line of the step joint, and the average penetration of the weld was measured to be 54%. The GC-MS analyses of trace organic components in the explosion debris provided a most interesting result. Although no evidence of organic explosives, oxidizers, or other unusual compounds was detected, the presence of an organic oil in the interior of the electrochemical cell was established. It is likely that the source of this oil was lubricating fluid from machining the metal cell components.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7876799

Grant, P M; Whipple, R E; Andresen, B D

1995-01-01

375

Electrochemical detection of catecholamine exocytosis using planar iridium oxide electrodes in nanoliter microfluidic cell culture volumes  

PubMed Central

Release of neurotransmitters and hormones by Ca2+ regulated exocytosis is a fundamental cellular/molecular process that is disrupted in a variety of psychiatric, neurological, and endocrine disorders. Therefore, this area represents a relevant target for drug and therapeutic development, efforts that will be aided by novel analytical tools and devices that provide mechanistically rich data with increased throughput. Toward this goal, we have electrochemically deposited iridium oxide (IrOx) films onto planar thin film platinum electrodes (20×300µm2) and utilized these for quantitative detection of catecholamine exocytosis from adrenal chromaffin cells trapped in a microfluidic network. The IrOx electrodes show a linear response to norepinephrine in the range of 0–400µM, with a sensitivity of 23.1±0.5mA/(M·mm2). The sensitivity of the IrOx electrodes does not change in the presence of ascorbic acid, a substance commonly found in biological samples. A replica molded polydimethylsiloxane (PDMS) microfluidic device with nanoliter sensing volumes was aligned and sealed to a glass substrate with the sensing electrodes. Small populations of chromaffin cells were trapped in the microfluidic sensing chamber and stimulated by rapid perfusion with high potassium (50mM) containing Tyrode’s solution at a flow rate of 1nL/s. Stimulation of the cells produced a rapid increase in current due to oxidation of the released catecholamines, with an estimated maximum concentration in the microfluidic device ~52µM. Thus, we demonstrate the utility of an integrated microfluidic network with IrOx electrodes for real-time quantitative detection of catecholamines released from small populations of cells.

Ges, Igor A.; Currie, Kevin P.M.; Baudenbacher, Franz

2013-01-01

376

Physical, mechanical and electrochemical characterization of all-perovskite intermediate temperature solid oxide fuel cells  

NASA Astrophysics Data System (ADS)

Strontium- and magnesium-doped lanthanum gallate (LSGM) has been considered as a promising electrolyte for solid oxide fuel cell (SOFC) systems in recent years due to its high ionic conductivity and chemical stability over a wide range of oxygen partial pressures and temperatures. This research describes synthesis, physical and mechanical behavior, electrochemical properties, phase evolution, and microstructure of components of an all-perovskite anode-supported intermediate temperature solid oxide fuel cell (ITSOFC), based on porous La 0.75Sr0.25Cr0.5Mn0.5O3 (LSCM) anode, La0.8Sr0.2Ga0.8Mg0.2O 2.8 (LSGM) electrolyte, and porous La0.6Sr0.4Fe 0.8Co0.2O3 (LSCF) cathode. The phase evolution of synthesized LSGM and LSCM powders has been investigated, and it has been confirmed that there is no reaction between LSGM and LSCM at sintering temperature. Using different amounts of poreformers and binders as well as controlling firing temperature, porosity of the anode was optimized while still retaining good mechanical integrity. The effect of cell operation conditions under dry hydrogen fuel on the SOFC open circuit voltage (OCV) and cell performance were also investigated. Characterization study of the synthesized LSGM indicates that sintering at 1500°C obtains higher electrical conductivity compared to the currently published results, while conductivity of pellets sintered at 1400°C and 1450°C would be slightly lower. The effect of sintering temperature on bulk and grain boundary resistivities was also discussed. The mechanical properties, such as hardness, Young's modulus, fracture toughness and modulus of rupture of the electrolyte were determined and correlated with scanning electron microscopy (SEM) morphological characterization. Linear thermal expansion and thermal expansion coefficient of LSGM were also measured.

Mohammadi, Alidad

377

Development of Secondary Inclusions in Cells Infected by Chlamydia trachomatis  

Microsoft Academic Search

The chlamydiae are obligate intracellular bacteria that occupy a nonacidified vacuole (the inclusion) during their entire developmental cycle. These bacteria produce a set of proteins (Inc proteins) that localize to the surface of the inclusion within infected cells. Chlamydia trachomatis IncA is also commonly found in long fibers that extend away from the inclusion. We used standard and confocal immunofluorescence

Robert J. Suchland; Daniel D. Rockey; Damir T. Alzhanov; Walter E. Stamm

2005-01-01

378

Electrochemical sensors, MTT and immunofluorescence assays for monitoring the proliferation effects of cissus populnea extracts on Sertoli cells  

PubMed Central

Background We describe the development of an electrochemical sensor array for monitoring the proliferation effects of cissus populnea plant extracts on TM4 Sertoli cells. Methods The proliferation activities of the extracts on Sertoli cells were studied using a high-throughput electrochemical sensor array (DOX-96) and the analytical sensor characteristics were compared with conventional colorimetric MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and fluorescence spectroscopy. Results This work shows that there is a definite positive trend in the proliferation effect of the extract of Cissus populnea on the TM4 Sertoli cells. All of the three techniques confirmed that the most effective concentration for the proliferation is 10 ppm. At this concentration, the proliferation effect was established around 120% for both DOX-96 and MTT techniques, whereas fluorescence assays showed a higher level (120-150%). DOX-96 showed a lower limit of detection (1.25 × 10(4) cells/ml); whereas the LOD recorded for both MTT and fluorescence techniques was 2.5 × 10(4) cells/ml. Visual examination of the cells by means of confocal fluorescence microscopy confirmed the proliferation of Sertoli cells as was determined using the MTT assay. This investigation provides a confident interpretation of the results and proved that the most effective concentration for the proliferation using Cissus populnea plant extract is 10 ppm. Conclusions Overall, the DOX results compared well with the conventional methods of checking proliferation of cells. The fascinating feature of the sensor array is the ability to provide continuous proliferation experiments with no additional reagents including 96 simultaneous electrochemical experiments. The use of the DOX-96 could reduce a typical bioassay time by 20-fold. Thus the DOX-96 can be used as both a research tool and for practical cell culture monitoring.

2011-01-01

379

Non-Faradaic electrochemical modification of catalytic activity: the work function of metal electrodes in solid electrolyte cells  

Microsoft Academic Search

The catalytic activity and selectivity of metal films used as electrodes in solid electrolyte cells can be altered dramatically and reversibly by polarizing the metal-sohd electrolyte interface This effect, termed non-Faradalc electrochemical modification of catalytic act tvaty (NEMCA) leads to steady state catalytic rate increases up to 3 X l 0 s t~mes higher than the steady state rate of

Costas G. Vayenas; Symeon Bebelis; Ioannis V. Yentekakis; Stelios Neophytides

1992-01-01

380

Electrochemical production of polysulfides and sodium hydroxide from white liquor: Part II: Electrolysis in a laboratory scale flow cell  

Microsoft Academic Search

Electrochemical production of polysulfide-containing white liquor and pure sodium hydroxide solution was investigated at 90°C in a laboratory scale flow cell. A mixed iridium–tantalum oxide coated titanium electrode was used as the anode and the two electrolyte compartments were separated by a cation-exchange membrane. The process was demonstrated at current densities up to 5kAm-2, resulting in high current efficiencies for

M. BEHM; D. SIMONSSON

1997-01-01

381

Flow-through electrochemical cell for accurate pH measurements at temperatures up to 400°C  

Microsoft Academic Search

We have developed a flow-through electrochemical cell (FTEC) and demonstrated that it operates successfully in both subcritical and supercritical aqueous environments at temperatures up to 400°C. The FTEC consists of a previously developed flow-through external (Ag?AgCl) pressure-balanced reference electrode (FTEPBRE) (Lvov et al., J. Electroanal. Chem. 444 (1998) 186) and a modified flow-through platinum hydrogen electrode (FTPHE). The experimental measurements

S. N. Lvov; X. Y. Zhou; D. D. Macdonald

1999-01-01

382

A high pressure single-pass high-conversion electrochemical cell for intensification of organic electrosynthesis processes  

Microsoft Academic Search

The anode oxidation of 4-methoxytoluene (4-MT) to 4-methoxybenzyl dimethylacetal (4-MBDMA) in methanol is used as a test reaction for the study of a microchannel electrochemical reactor operated continuously in a single-pass high-conversion mode. The cell consists of two stainless steel cathodes, grooved with 100?m deep channels surrounding a flat glassy carbon anode. Pressures up to 20 bars are applied in

Anis Attour; Patricia Dirrenberger; Sabine Rode; Athanassios Ziogas; Michael Matlosz; François Lapicque

2011-01-01

383

High-durability titanium bipolar plate modified by electrochemical deposition of platinum for unitized regenerative fuel cell (URFC)  

Microsoft Academic Search

The electrochemical deposition of platinum on a titanium bipolar plate (Pt\\/Ti) was studied for applications in a unitized regenerative fuel cell (URFC). Platinum deposition on the titanium plate was carried out in the platinum precursor solution (1.8gdm?3) at constant acidity (pH 1.0) and temperature (90°C). The pre-treatment of the titanium plate and the applied deposition current density were optimized to

Ho-Young Jung; Sheng-Yang Huang; Branko N. Popov

2010-01-01

384

Secondary Acute Monocytic Leukemia Occurring during the Treatment of a Testicular Germ Cell Tumor  

Microsoft Academic Search

Secondary leukemia following chemotherapy or radiotherapy for mediastinal germ cell tumors is a well-described entity. It also may occur in patients with testicular germ cell tumors. We report a case of acute monocytic leukemia occurring in a 44-year-old man who received etoposide-based chemotherapy and radiotherapy for a recurrent, metastatic testicular germ cell tumor. The patient recevied 14 cycles of systemic

Norio Nonomura; Nobukazu Murosaki; Yasuyuki Kojima; Nobuyuki Kondoh; Toshinobu Seguchi; Yoshito Takeda; Yusuke Oji; Hiroyasu Ogawa; Haruo Sugiyama; Tsuneharu Miki; Äkïhïko Okuyama

1997-01-01

385

Bioprocess considerations for production of secondary metabolites by plant cell suspension cultures  

Microsoft Academic Search

Plant cell culture provides a viable alternative over whole plant cultivation for the production of secondary metabolites.\\u000a In order to successfully cultivate the plant cells at large scale, several engineering parameters such as, cell aggregation,\\u000a mixing, aeration, and shear sensitivity are taken into account for selection of a suitable bioreactor. The media ingredients,\\u000a their concentrations and the environmental factors are

Saurabh Chattopadhyay; Sunita Farkya; Ashok K. Srivastava; Virendra S. Bisaria

2002-01-01

386

Optimization of microstructure of buckypaper-based proton exchange membrane fuel cell by using electrochemical impedance spectroscopy  

NASA Astrophysics Data System (ADS)

The microstructure of the catalyst layer in proton exchange membrane fuel cells (PEMFCs) greatly influences the utilization of the catalyst (Pt) and the overall cell performance. Research focused on two key components in optimizing the microstructure of PEMFCs, primarily the platinum loading and Nafion loading. An electrochemical impedance spectroscopy (EIS) experiment was performed, in order to study the effects of varying these two components and come to a conclusion on the optimal amount required to maximize cell performance of PEMFC's that are based on double-layered supported Pt (Pt/DLBP) catalyst.

Hagen, Mark

387

Peroxiredoxin II Regulates Effector and Secondary Memory CD8+ T Cell Responses  

PubMed Central

Reactive oxygen intermediates (ROI) generated in response to receptor stimulation play an important role in cellular responses. However, the effect of increased H2O2 on an antigen-specific CD8+ T cell response was unknown. Following T cell receptor (TCR) stimulation, the expression and oxidation of peroxiredoxin II (PrdxII), a critical antioxidant enzyme, increased in CD8+ T cells. Deletion of PrdxII increased ROI, S phase entry, division, and death during in vitro division. During primary acute viral and bacterial infection, the number of effector CD8+ T cells in PrdxII-deficient mice was increased, while the number of memory cells were similar to those of the wild-type cells. Adoptive transfer of P14 TCR transgenic cells demonstrated that the increased expansion of effector cells was T cell autonomous. After rechallenge, effector CD8+ T cells in mutant animals were more skewed to memory phenotype than cells from wild-type mice, resulting in a larger secondary memory CD8+ T cell pool. During chronic viral infection, increased antigen-specific CD8+ T cells accumulated in the spleens of PrdxII mutant mice, causing mortality. These results demonstrate that PrdxII controls effector CD8+ T cell expansion, secondary memory generation, and immunopathology.

Michalek, Ryan D.; Crump, Katie E.; Weant, Ashley E.; Hiltbold, Elizabeth M.; Juneau, Daniel G.; Moon, Eun-Yi; Yu, Dae-Yeul; Poole, Leslie B.

2012-01-01

388

Hermetically sealed electrical feedthrough for high temperature secondary cells  

DOEpatents

A passthrough seal is disclosed for electrically isolating the terminal in a lithium/metal sulfide cell from the structural cell housing. The seal has spaced upper and lower insulator rings fitted snuggly between the terminal and an annularly disposed upstanding wall, and outwardly of a powdered insulator also confined between the upstanding wall and terminal. The adjacent surfaces of the upper insulator ring and the respective upstanding wall and terminal are conically tapered, diverging in the axial direction away from the cell interior, and a sealing ring is located between each pair of the adjacent surfaces. The components are sized so that upon appropriate movement of the upper insulator ring toward the lower insulator ring the powdered insulator and sealing rings are each compressed to a high degree. This compacts the powdered insulator thereby rendering the same highly impervious and moreover fuses the sealing rings to and between the adjacent surfaces. The upper and lower insulator rings might be formed of beryllium oxide and/or alumina, the powdered insulator might be formed of boron nitride, and the sealing rings might be formed of aluminum.

Knoedler, Reinhard (Nussloch, DE); Nelson, Paul A. (Wheaton, IL); Shimotake, Hiroshi (Hinsdale, IL); Battles, James E. (Oak Forest, IL)

1985-01-01

389

Detecting bifurcations in an electrochemical cell employing an assisted reference model strategy.  

PubMed

Bifurcations are detected in experiments involving the electrochemical oxidation of copper in phosphoric acid. Ideally, a bifurcation detection protocol requires a model with good qualitative and quantitative prediction capabilities that is also able to reproduce the drift inherent to the electrochemical experiment. A generic protocol for manipulation of nonlinear systems is proposed to achieve this goal. This protocol is based on a good qualitative predictor coupled to a modified Kalman filter that corrects the quantitative errors of the model point by point, adapting to the slowly varying conditions imposed by the electrochemical drift. PMID:23276166

Ramírez-Álvarez, E; Calderón Ramírez, M; Rico-Martínez, R; González-Figueredo, C; Parmananda, P

2013-01-14

390

The toughness of secondary cell wall and woody tissue  

PubMed Central

The 'across grain' toughness of 51 woods has been determined on thin wet sections using scissors. The moisture content of sections and the varying sharpness of the scissor blades had little effect on the results. In thin sections (less than 0.6mm), toughness rose linearly with section thickness. The intercept toughness at zero thickness, estimated from regression analysis, was proportional to relative density, consistent with values reported for non-woody plant tissues. Extrapolation of the intercept toughness of these woods and other plant tissues/materials to a relative density of 1.0 predicted a toughness of 3.45kJ m-2 , which we identify with the intrinsic toughness of the cell wall. This quantity appears to predict published results from KIC tests on woods and is related to the propensity for crack deflection. The slope of the relationship between section thickness and toughness, describing the work of plastic buckling of cells, was not proportional to relative density, the lightest (balsa) and heaviest (lignum vitae) woods fracturing with less plastic work than predicted. The size of the plastic zone around the crack tip was estimated to be 0.5mm in size. From this, the hypothetical overall toughness of a thick (greater than 1 mm) block of solid cell wall material was calculated as 39.35 kJ m-2, due to both cell wall resistance (10 per cent) and the plastic buckling of cells (90 per cent). This value successfully predicts the toughness of most commercial woods (of relative densities between 0.2 and 0.8) from 'work area' tests in tension and bending. Though density was the most important factor, both fibre width/fibre length (in hardwoods) and lignin/cellulose ratios were negatively correlated with the work of plastic buckling, after correcting for density. At low densities the work of plastic buckling in the longitudinal radial (LR) direction exceeded that in longitudinal tangential (LT), but the reverse was true for relative densities above 0.25. This could be attributed to the direction of rays. Density for density, the toughness of temperate hardwoods tested was about 20 per cent lower than that of tropical hardwoods. This is probably due to the much greater number of vessels in temperate hardwoods. Vessels appear either not to display buckling behaviour during fracture at all or to collapse cheaply. These general results have applications to other plant tissues.

Lucas, P. W.; Tan, H. T. W.; Cheng, P. Y.

1997-01-01

391

Method of bonding a conductive layer on an electrode of an electrochemical cell  

DOEpatents

A dense, electronically conductive interconnection layer is bonded onto a porous, tubular, electronically conductive air electrode structure, optionally supported by a ceramic support, by (A) providing an air electrode surface, (B) forming on a selected portion of the electrode surface, without the use of pressure, particles of LaCrO[sub 3] doped with an element selected from the group consisting of Sr, Mg, Ca, Ba, Co, and mixtures thereof, where the particles have a deposit on their surface comprising calcium oxide and chromium oxide; (C) heating the particles with the oxide surface deposit in an oxidizing atmosphere at from 1,300 C to 1,550 C, without the application of pressure, to provide a dense, sintered, interconnection material bonded to the air electrode, where calcium and chromium from the surface deposit are incorporated into the structure of the LaCrO[sub 3]. A solid electrolyte layer can be applied to the uncovered portion of the air electrode, and a fuel electrode can be applied to the solid electrolyte, to provide an electrochemical cell. 4 figs.

Bowker, J.C.; Singh, P.

1989-08-29

392

Method of bonding a conductive layer on an electrode of an electrochemical cell  

DOEpatents

A dense, electronically conductive interconnection layer 26 is bonded onto a porous, tubular, electronically conductive air electrode structure 16, optionally supported by a ceramic support 22, by (A) providing an air electrode surface, (B) forming on a selected portion of the electrode surface 24, without the use of pressure, particles of LaCrO.sub.3 doped with an element selected from the group consisting of Sr, Mg, Ca, Ba, Co, and mixtures thereof, where the particles have a deposit on their surface comprising calcium oxide and chromium oxide; (C) heating the particles with the oxide surface deposit in an oxidizing atmosphere at from 1,300.degree. C. to 1,550.degree. C., without the application of pressure, to provide a dense, sintered, interconnection material 26 bonded to the air electrode 16, where calcium and chromium from the surface deposit are incorporated into the structure of the LaCrO.sub.3. A solid electrolyte layer 18 can be applied to the uncovered portion of the air electrode, and a fuel electrode 20 can be applied to the solid electrolyte, to provide an electrochemical cell 10.

Bowker, Jeffrey C. (Richland Township, Allegheny County, PA); Singh, Prabhakar (Pittsburgh, PA)

1989-01-01

393

Luminescent ionic transition-metal complexes for light-emitting electrochemical cells.  

PubMed

Higher efficiency in the end-use of energy requires substantial progress in lighting concepts. All the technologies under development are based on solid-state electroluminescent materials and belong to the general area of solid-state lighting (SSL). The two main technologies being developed in SSL are light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs), but in recent years, light-emitting electrochemical cells (LECs) have emerged as an alternative option. The luminescent materials in LECs are either luminescent polymers together with ionic salts or ionic species, such as ionic transition-metal complexes (iTMCs). Cyclometalated complexes of Ir(III) are by far the most utilized class of iTMCs in LECs. Herein, we show how these complexes can be prepared and discuss their unique electronic, photophysical, and photochemical properties. Finally, the progress in the performance of iTMCs based LECs, in terms of turn-on time, stability, efficiency, and color is presented. PMID:22887710

Costa, Rubén D; Ortí, Enrique; Bolink, Henk J; Monti, Filippo; Accorsi, Gianluca; Armaroli, Nicola

2012-08-13

394

Electrochemical Characteristics of Tin Oxide-Graphite as Anode Material for Lithium-ion Cells  

NASA Astrophysics Data System (ADS)

Tin oxide anode materials used in lithium-ion cells experience large volume changes during charging and discharging which cause substantial losses in capacity. In this work, the tin oxide-graphite composite is proposed as an alternative anode material to overcome this problem. The composite was synthesised from a solution of tin chloride dihydrate and graphite powders with citric acid as the chelating agent. In this sol-gel method, a solid phase is formed through a chemical reaction in a liquid phase at moderate temperature. The technique offers several advantages compared to the solid state synthesis technique such as the ability to maintain the homogeneous mixture of precursors during synthesis and to produce small particles. The electrochemical behaviour of the anode material was investigated by means of galvanostatic charge discharge technique. An initial reversible capacity of 748 mAh/g is obtained and nearly 600 mAh/g was retained upon the reaching the fifth cycle. This study shows that the presence of graphite is able to minimise the agglomeration of tin particles that causes large volume changes during cycling, thereby improving cyclability of the anode material.

Hasanaly, Siti Munirah

2010-03-01

395

Electrochemical Characterization of Hydrothermally Synthesized Pt--Ru--Ni--P Catalyst for Direct Methanol Fuel Cell  

NASA Astrophysics Data System (ADS)

Pt--Ru--Ni--P/multiwalled carbon nanotube (MWCNT) catalyst is synthesized by a hydrothermal process using sodium hypophosphite (NaH2PO2) as a reducing agent. The particle size is evaluated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrocatalytic activity of a Pt--Ru--Ni--P/MWCNT catalyst for methanol electro-oxidation has been studied by cyclic voltammetry, chromoamperometry, and impedance spectroscopy. TEM images reveal that the Pt--Ru--Ni--P nanoparticles have a wide size distribution with an average size of 3.2 nm. Pt--Ru--Ni--P/MWCNT catalyst shows an electrochemically active surface area of 63.2 m2 g-1 and a mass activity of 187.56 mA mg Pt-1. It has been found that the presence of phosphorus as an interstitial species can enhance the dispersion as well as reduce the size of Pt--Ru--Ni--P nanoparticles. Moreover, incorporation of phosphorus into the Pt--Ru--Ni/MWCNT catalyst shows a 1.5 times higher electrocatalytic activity. The power density (57 mW cm-1) of the Pt--Ru--Ni--P/MWCNT catalyst in fuel cell tests is higher than that (40 mW cm-1) of the Pt--Ru--Ni/MWCNT catalyst.

Lee, Seok-Hee; Kim, Dong-Joo; Yoon, Young-Soo

2013-03-01

396

Precise Color Tuning via Hybrid Quantum Dot Light-Emitting Electrochemical Cells  

NASA Astrophysics Data System (ADS)

Quantum dots (QDs) are of much interest as the active emitter in an organic light-emitting device due to their size-tunable band-gap energies, allowing device color to be carefully tuned over the entire spectrum by simply varying the size of QDs used. Colloidal QDs are compatible with solution processing techniques used to fabricate polymer light-emitting devices, resulting in inexpensive, low temperature, large area device fabrication on flexible substrates. QDs are more stable and have higher photoluminescence efficiency than organic emitters, but their efficacy in a typical polymer LED is limited by an insulating surface ligand layer that presents a charge tunneling barrier. This leads to unwanted emission from the polymer host material. A light-emitting electrochemical cell (LEC) structure presents a novel solution to this problem by limiting the emissive region thickness in the polymer/QD film. Emission spectra of QD-LECs composed of a two different sizes of QDs blended into a single polymer film show better color purity than polymer-only LECs, with nearly pure emission from the QDs. Relative intensity of the two narrow QD emission peaks is precisely controlled by varying the mass ratio between the QDs, directly changing device color. This novel QD-LEC structure has the potential to improve the performance of polymer optoelectronic devices, particularly in solid-state lighting.

Norell Bader, Amanda; Ilkevich, Anton; Leger, Janelle

2010-10-01

397

Light-emitting electrochemical cells using polymeric ionic liquid/polyfluorene blends as luminescent material  

NASA Astrophysics Data System (ADS)

We report the use of blends composed of poly(9,9'-dioctylfluorene-alt-benzothiadiazole), F8BT, and a polymeric ionic liquid (PIL), poly(vinyl-ethylimidazolium bistrifluoromethanesulfonimide), as the active layer in light-emitting electrochemical cells (LECs) with the simple indium-tin-oxide/active-layer/Al configuration. The PIL provides both the ionic charge and the transport channel necessary for the devices to operate as LECs resulting in reduction of charge injection barriers at the electrode/active-layer interfaces. We find that the performance of devices using PIL:F8BT blends improved with respect to pure F8BT with maximum luminance increasing from 10-20 cd/m2 for pure F8BT to 2000-4000 cd/m2 for blends. Turn-on voltages were also reduced from above 7 V down to around 3.6-4 V. The maximum external quantum efficiency was increased from 10-3%-10-4% to values higher than 0.1%.

Marcilla, Rebeca; Mecerreyes, David; Winroth, Gustaf; Brovelli, Sergio; Del Mar Rodriguez Yebra, Maria; Cacialli, Franco

2010-01-01

398

Separation of competitive microorganisms using anaerobic membrane bioreactors as pretreatment to microbial electrochemical cells.  

PubMed

Anaerobic membrane bioreactors (AnMBRs) as pretreatment to microbial electrochemical cells (MECs) were first assessed for improving energy recovery. A dual-chamber MEC was operated at hydraulic retention time (HRT) ranging from 1 to 8d, while operating conditions for an AnMBR were fixed. Current density was increased from 7.5±0 to 14±1A/m(2) membrane with increasing HRT. MEC tests with AnMBR permeate (mainly propionate and acetate) and propionate medium confirmed that propionate was fermented to acetate and hydrogen gas, and anode-respiring bacteria (ARB) utilized these fermentation products as substrate. Membrane separation in the AnMBR excluded fermenters and methanogens from the MEC, and thus no methane production was found in the MEC. The lack of fermenters, however, slowed down propionate fermentation rate, which limited current density in the MEC. To symphonize fermenters, H2-consumers, and ARB in biofilm anode is essential for improving current density, and COD removal. PMID:24047682

Dhar, Bipro Ranjan; Gao, Yaohuan; Yeo, Hyeongu; Lee, Hyung-Sool

2013-08-31

399

Roles of microtubules and cellulose microfibril assembly in the localization of secondary-cell-wall deposition in developing tracheary elements  

Microsoft Academic Search

Summary. The roles of cellulose microfibrils and cortical microtubules in establishing and maintaining the pattern of secondary-cell-wall deposition in tracheary elements were investigated with direct dyes to inhibit cellulose microfibril assembly and amiprophosmethyl to inhibit microtubule polymerization. When direct dyes were added to xylogenic cultures of Zinnia elegans L. mesophyll cells just before the onset of differentiation, the secondary cell

A. W. Roberts; A. O. Frost; E. M. Roberts; C. H. Haigler

2004-01-01

400

Thermodynamic and kinetic study of mixed metal oxide cathode material for lithium organic polymer electrolyte electrochemical cells  

NASA Astrophysics Data System (ADS)

The thermodynamics and discharge kinetics of the lithium/bismuth modified manganese dioxide electrochemical couple was investigated. These investigations coupled with biased impedance spectroscopy studies lead to the establishment of a model of the electrochemical interfaces of the system. Biased impedance spectroscopy allows for the study of the electrodes during open circuit and discharge conditions. This ability to study the electrode interface during discharge allowed for the development of an equivalent circuit and description of the complex interface of the mixed metal oxide. The results of these techniques were the establishment of a theory of the discharge mechanism of the lithium/bismuth modified manganese dioxide electrochemical cell and the processes involved. Equivalent circuit analysis of materials provides data for comparison. Equivalent circuit analysis when used with biased impedance spectroscopy provides valued component data for lithium battery cathode material. The model, therefore, provides an invaluable tool in the investigation of new materials for use as lithium battery cathodes. Kinetic measurements were used to determine the catalytic nature of the bismuth phase in bismuth modified manganese dioxide lithium primary battery cathode material. A reduction in activation energy for lithium cells was identified in the bismuth manganese mixed metal oxide as compared to manganese dioxide. Impedance spectroscopy allowed for the identification of an additional process linked to the catalytic behavior of the bismuth oxide phase of the bismuth manganese mixed metal oxide. An additional part of the studies focused on the thermodynamics and kinetics of the lithium polymer electrolyte cells with bismuth manganese mixed metal oxide cathodes. This study resulted in the determination of thermodynamic properties of the electrochemical couple. Discharge kinetic measurements lead to the establishment of optimum cathode formulations. This optimization considered both gravimetric and volumetric efficiencies. Measurements examined the relationship between discharge characteristics and cathode material concentration and cathode thickness.

Atwater, Terrill Bradford

1997-09-01

401

Automated Targeting of Cells to Electrochemical Electrodes Using a Surface Chemistry Approach for the Measurement of Quantal Exocytosis  

PubMed Central

Here, we describe a method to fabricate a multichannel high-throughput microchip device for the measurement of quantal transmitter release from individual cells. Instead of bringing carbon-fiber electrodes to cells, the device uses a surface chemistry approach to bring cells to an array of electrochemical microelectrodes. The microelectrodes are small and cytophilic in order to promote adhesion of a single cell, whereas all other areas of the chip are covered with a thin cytophobic film to block cell attachement and facilitate the movement of cells to electrodes. This cytophobic film also insulates unused areas of the conductive film; thus, the alignment of cell docking sites to working electrodes is automatic. Amperometric spikes resulting from single-granule fusion events were recorded on the device and had amplitudes and kinetics similar to those measured using carbon-fiber microelectrodes. Use of this device will increase the pace of basic neuroscience research and may also find applications in drug discovery or validation.

2010-01-01

402

Filming a live cell by scanning electrochemical microscopy: label-free imaging of the dynamic morphology in real time  

PubMed Central

The morphology of a live cell reflects the organization of the cytoskeleton and the healthy status of the cell. We established a label-free platform for monitoring the changing morphology of live cells in real time based on scanning electrochemical microscopy (SECM). The dynamic morphology of a live human bladder cancer cell (T24) was revealed by time-lapse SECM with dissolved oxygen in the medium solution as the redox mediator. Detailed local movements of cell membrane were presented by time-lapse cross section lines extracted from time-lapse SECM. Vivid dynamic morphology is presented by a movie made of time-lapse SECM images. The morphological change of the T24 cell by non-physiological temperature is in consistence with the morphological feature of early apoptosis. To obtain dynamic cellular morphology with other methods is difficult. The non-invasive nature of SECM combined with high resolution realized filming the movements of live cells.

2012-01-01

403

Comparative structure and biomechanics of plant primary and secondary cell walls  

PubMed Central

Recent insights into the physical biology of plant cell walls are reviewed, summarizing the essential differences between primary and secondary cell walls and identifying crucial gaps in our knowledge of their structure and biomechanics. Unexpected parallels are identified between the mechanism of expansion of primary cell walls during growth and the mechanisms by which hydrated wood deforms under external tension. There is a particular need to revise current “cartoons” of plant cell walls to be more consistent with data from diverse approaches and to go beyond summarizing limited aspects of cell walls, serving instead as guides for future experiments and for the application of new techniques.

Cosgrove, Daniel J.; Jarvis, Michael C.

2012-01-01

404

Continuous Organic Electrochemical Synthesis.  

National Technical Information Service (NTIS)

The electrochemical oxidation of glucose to gluconic acid and reduction of glucose to sorbitol has been successfully paired in an undivided packed bed electrode flow cell. The use of a Raney nickel powder catalytic cathode significantly improved the curre...

K. Nobe M. Baizer P. Pintauro K. Park S. Gilbert

1984-01-01

405

Electrochemical heat engine  

DOEpatents

Electrochemical heat engines produce electrochemical work, and mechanical motion is limited to valve and switching actions as the heat-to-work cycles are performed. The electrochemical cells of said heat engines use molten or solid electrolytes at high temperatures. One or more reactions in the cycle will generate a gas at high temperature which can be condensed at a lower temperature with later return of the condensate to electrochemical cells. Sodium, potassium, and cesium are used as the working gases for high temperature cells (above 600 K) with halogen gases or volatile halides being used at lower temperature. Carbonates and halides are used as molten electrolytes and the solid electrolyte in these melts can also be used as a cell separator.

Elliott, Guy R. B. (Los Alamos, NM); Holley, Charles E. (Alcalde, NM); Houseman, Barton L. (Cockeysville, MD); Sibbitt, Jr., Wilmer L. (Albuquerque, NM)

1978-01-01

406

Design, Evaluation, and Application of Continuous Flow Cells for Organic Electrochemical Synthesis. Progress Report.  

National Technical Information Service (NTIS)

The strategy of paired electrochemical synthesis for the production of organic chemicals can result in as much as a 50% reduction in energy consumption, as compared to conventional electroorganic synthesis. A continuation of the research in paired synthes...

K. Nobe

1982-01-01

407

Novel Concepts in Electrochemical Solar Cells. Quarterly Technical Progress Report, December 15, 1980-March 15, 1981.  

National Technical Information Service (NTIS)

During the past quarter, the following areas were emphasized: (a) characterization of redox couples with very positive potentials in room-temperature AlCl sub 3 -BPC electrolytes and comparison of the electrochemical behavior of decamethyl ferrocene in th...

1981-01-01

408

Li-alloy electrode for Li-alloy/metal sulfide cells  

DOEpatents

A method of making a negative electrode, the electrode made thereby and a secondary electrochemical cell using the electrode. Lithium, silicon and nickel is alloyed in a prescribed proportion forming an electroactive material, to provide an improved electrode and cell.

Kaun, Thomas D. (320 Willow St., New Lenox, IL 60451)

1996-01-01

409

A microwell device for targeting single cells to electrochemical microelectrodes for high-throughput amperometric detection of quantal exocytosis  

PubMed Central

Electrochemical microelectrodes are commonly used to detect spikes of amperometric current that correspond to exocytosis of oxidizable transmitter from individual vesicles, i.e., quantal exocytosis. We are developing transparent multi- electrochemical electrode arrays on microchips in order to automate measurement of quantal exocytosis. Here we report development of an improved device to target individual cells to each microelectrode in an array. Efficient targeting (~75%) is achieved using cell-sized micro-well traps fabricated in SU-8 photoresist together with patterning of poly (L-lysine) in register with electrodes to promote cell adhesion. The surface between electrodes is made resistant to cell adhesion using poly (ethylene glycol) in order to facilitate movement of cells to electrode “docking sites”. We demonstrate the activity of the electrodes using the test analyte ferricyanide and perform recordings of quantal exocytosis from bovine adrenal chromaffin cells on the device. Multiple cell recordings on a single device demonstrate the consistency of spike measurements and multiple recordings from the same electrodes demonstrate that the device can be cleaned and reused without degradation of performance. The new device will enable high-throughput studies of quantal exocytosis and may also find application in rapidly screening drugs or toxins for effects on exocytosis.

Liu, Xin; Barizuddin, Syed; Shin, Wonchul; Mathai, Cherian J.; Gangopadhyay, Shubhra; Gillis, Kevin D.

2011-01-01

410

Design parameters for an electrochemical cell with porous electrode to treat metal–ion solution  

Microsoft Academic Search

An electrochemical reactor was designed and operated to treat the solution containing copper ions. Design parameters for the electrochemical reactor using the porous cathode and RuO2\\/IrO2\\/Ti anode were investigated. The porous cathode was prepared by the electroless nickel deposition on polyurethane. The apparent current, the gap between cathode and anode, and hydraulic retention time (HRT) were selected as design parameters.

Daewon Pak; Dowon Chung; Jeh Beck Ju

2001-01-01

411

Aldh1-expressing endocrine progenitor cells regulate secondary islet formation in larval zebrafish pancreas.  

PubMed

Aldh1 expression is known to mark candidate progenitor populations in adult and embryonic mouse pancreas, and Aldh1 enzymatic activity has been identified as a potent regulator of pancreatic endocrine differentiation in zebrafish. However, the location and identity of Aldh1-expressing cells in zebrafish pancreas remain unknown. In this study we demonstrate that Aldh1-expressing cells are located immediately adjacent to 2F11-positive pancreatic ductal epithelial cells, and that their abundance dramatically increases during zebrafish secondary islet formation. These cells also express neurod, a marker of endocrine progenitor cells, but do not express markers of more mature endocrine cells such as pax6b or insulin. Using formal cre/lox-based lineage tracing, we further show that Aldh1-expressing pancreatic epithelial cells are the direct progeny of pancreatic notch-responsive progenitor cells, identifying them as a critical intermediate between multi-lineage progenitors and mature endocrine cells. Pharmacologic manipulation of Aldh1 enzymatic activity accelerates cell entry into the Aldh1-expressing endocrine progenitor pool, and also leads to the premature maturation of these cells, as evidenced by accelerated pax6b expression. Together, these findings suggest that Aldh1-expressing cells act as both participants and regulators of endocrine differentiation during zebrafish secondary islet formation. PMID:24147152

Matsuda, Hiroki; Parsons, Michael J; Leach, Steven D

2013-09-17

412

Aldh1-Expressing Endocrine Progenitor Cells Regulate Secondary Islet Formation in Larval Zebrafish Pancreas  

PubMed Central

Aldh1 expression is known to mark candidate progenitor populations in adult and embryonic mouse pancreas, and Aldh1 enzymatic activity has been identified as a potent regulator of pancreatic endocrine differentiation in zebrafish. However, the location and identity of Aldh1-expressing cells in zebrafish pancreas remain unknown. In this study we demonstrate that Aldh1-expressing cells are located immediately adjacent to 2F11-positive pancreatic ductal epithelial cells, and that their abundance dramatically increases during zebrafish secondary islet formation. These cells also express neurod, a marker of endocrine progenitor cells, but do not express markers of more mature endocrine cells such as pax6b or insulin. Using formal cre/lox-based lineage tracing, we further show that Aldh1-expressing pancreatic epithelial cells are the direct progeny of pancreatic notch-responsive progenitor cells, identifying them as a critical intermediate between multi-lineage progenitors and mature endocrine cells. Pharmacologic manipulation of Aldh1 enzymatic activity accelerates cell entry into the Aldh1-expressing endocrine progenitor pool, and also leads to the premature maturation of these cells, as evidenced by accelerated pax6b expression. Together, these findings suggest that Aldh1-expressing cells act as both participants and regulators of endocrine differentiation during zebrafish secondary islet formation.

Matsuda, Hiroki; Parsons, Michael J.; Leach, Steven D.

2013-01-01

413

Direct numerical simulation of transport and electrochemical reaction in battery and fuel cell electrodes  

NASA Astrophysics Data System (ADS)

Batteries and fuel cells are widely used to generate electrical energy, especially in recent applications to electric and hybrid vehicles. To simulate a porous electrode for batteries and fuel cells, macro-homogeneous models are often employed in which the actual morphology of the electrode is ignored, thereby making computations much easier. However, such models are based on the volume-averaging technique, which smears the microscopically complex interfacial structures and has to invoke empirical correlations for describing the effective transport properties in a multiphase system. In this work, a methodology is developed to achieve the description on the pore level based on direct numerical simulation (DNS) method. The DNS solves the accurate point-wise conservation equations on a real micro-structure of the porous electrode and hence utilizes the intrinsic transport properties for each phase. To demonstrate the DNS method, an idealized morphology and further a random microstructure are constructed to represent all the phases composing the porous electrode. A single set of conservation equations of charge and species valid in all phases are developed and numerically solved using a finite volume technique. The present DNS model is first applied to simulate the behavior of an intercalative carbon electrode in the widely used lithium-ion cell. The concentration and potential distributions in both solid and electrolyte phases at the pore level are obtained across the electrode during the discharge. The species and charge transport processes, as well as the electrochemical reactions, are computationally visualized when discharging the electrode. In addition, empirical correlations in porous electrode theory, which describe the dependency of effective properties (diffusion coefficient, conductivity, etc.) on the porosity, are corroborated using the fundamental DNS data. Then the discharge processes of a full lithium ion cell at various rates are simulated with DNS approach and verified by the experimental data. In the application to the cathode catalyst layer of PEM fuel cells, DNS is employed to identify three characteristic voltage losses: kinetics losses, ohmic losses and O2 transport losses. On a constructed random microstructure, DNS is also utilized to optimize the inlet air humidity and the composition design and hence achieve the minimum voltage loss during operation. In summary, the newly developed DNS method has provided an effective method to simulate behavior of thin porous electrodes with microscopically complicated geometries and the fundamentals insight into structure-performance relationships of porous electrodes for the first time.

Wang, Guoqing

414

Influence of KOH-activated graphite nanofibers on the electrochemical behavior of Pt-Ru nanoparticle catalysts for fuel cells  

NASA Astrophysics Data System (ADS)

Graphite nanofibers (GNFs) were activated chemically by a heat treatment at between 700 and 1000 °C. The GNFs were used as carbon supports for Pt-Ru nanoparticles in fuel cells. The surface, structural, and textural characteristics of the carbon supports and Pt-Ru/KOH-activated GNFs catalysts were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and surface area analyzer, respectively. The electrochemical activity was examined by cyclic voltammetry. The results showed that the concentration of oxygen functional groups and the specific surface area of the carbon supports increased with increasing activation temperature up to 900 °C, whereas the mean Pt-Ru nanoparticle size decreased due to an improvement in the dispersibility of the Pt-Ru/KOH-activated GNFs catalysts. From the results, it was found that the electrochemical activities of the Pt-Ru/KOH-activated GNFs catalysts were improved by the larger active surface area available due to an increase in the number of oxygen functional groups and specific surface area, resulting in the enhanced electrochemical activity for use in fuel cells.

Lee, Seul-Yi; Kim, Byung-Ju; Park, Soo-Jin

2013-03-01

415

Promoting effect of layered titanium phosphate on the electrochemical and photovoltaic performance of dye-sensitized solar cells.  

PubMed

We reported a composite electrolyte prepared by incorporating layered ?-titanium phosphate (?-TiP) into an iodide-based electrolyte using 1-ethyl-3-methylimidazolium tetrafluoroborate(EmimBF4) ionic liquid as solvent. The obtained composite electrolyte exhibited excellent electrochemical and photovoltaic properties compared to pure ionic liquid electrolyte. Both the diffusion coefficient of triiodide (I3-) in the electrolyte and the charge-transfer reaction at the electrode/electrolyte interface were improved markedly. The mechanism for the enhanced electrochemical properties of the composite electrolyte was discussed. The highest conversion efficiency of dye-sensitized solar cell (DSSC) was obtained for the composite electrolyte containing 1wt% ?-TiP, with an improvement of 58% in the conversion efficiency than the blank one, which offered a broad prospect for the fabrication of stable DSSCs with a high conversion efficiency. PMID:20676195

Cheng, Ping; Chen, Ruihao; Wang, Junfei; Yu, Jianong; Lan, Tian; Wang, Wanjun; Yang, Haijun; Wu, Haixia; Deng, Changsheng

2010-05-20

416

Electrochemical oxidation of glucose using mutant glucose oxidase from directed protein evolution for biosensor and biofuel cell applications.  

PubMed

In this study, electrochemical characterisation of glucose oxidation has been carried out in solution and using enzyme polymer electrodes prepared by mutant glucose oxidase (B11-GOx) obtained from directed protein evolution and wild-type enzymes. Higher glucose oxidation currents were obtained from B11-GOx both in solution and polymer electrodes compared to wt-GOx. This demonstrates an improved electrocatalytic activity towards electrochemical oxidation of glucose from the mutant enzyme. The enzyme electrode with B11-GOx also showed a faster electron transfer indicating a better electronic interaction with the polymer mediator. These encouraging results have shown a promising application of enzymes developed by directed evolution tailored for the applications of biosensors and biofuel cells. PMID:21915588

Yu, Eileen Hao; Prodanovic, Radivoje; Güven, Güray; Ostafe, R; Schwaneberg, U

2011-09-14

417

THE MECHANISM OF ANTIGENIC STIMULATION OF PRIMARY AND SECONDARY CLONAL PRECURSOR CELLS  

PubMed Central

Cell transfers to carrier-immunized irradiated mice have permitted an analysis of the in vitro stimulation of clonal precursors of anti-2,4-dinitrophenyl (DNP) antibody-producing cells derived from both immune and nonimmune mice. The results indicate that: (a) carrier-specific enhancement is obligatory for stimulation of primary precursor cells and increases both the size and number of detectable foci derived from secondary precursors. (b) This carrier-specific enhancement is most apparent in the stimulation of precursors of high-affinity antibody producer cells. (c) The antibody produced by primary foci, like that of secondary foci, appears homogeneous. (d) The frequency of clonal precursors in normal spleens is 38% that in spleens from mice 4–8 months after immunization, and the number of such precursors in normal spleens can be reduced fivefold by specific suppression of donor mice with soluble antigen. (e) The average of association constants of primary monofocal antibodies, like that of primary serum antibody produced in carrier-primed mice, is less than 10-fold lower than that of secondary clonal or serum antibody. (f) The affinity of primary monofocal antibodies shows a slight dependence on stimulating antigen concentration; however, a minimum threshold affinity consonant with stimulation is apparent. (g) Free hapten inhibits antigenic stimulation of primary precursor cells at a much lower concentration than is required for the inhibition of secondary precursors. These results are interpreted as indicating that (a) primary stimulation, like secondary stimulation, results from the selective stimulation by antigen of a population of cells differing from one another in their potential antibody product but each having only a single such product; (b) the antigen receptors of primary cells interact with antigen as if they are monovalent while receptors of secondary cells evidence multivalence; (c) antigenic stimulation appears to require both a relatively high affinity of receptors for bound antigen and an interlinking of receptors through such antigen; stimulation is thus seen as resulting from a stabilization of receptors within antigen-receptor aggregates to the cell surface; (d) T-cells appear to serve both in cross-linking antigens and in amplifying the size of stimulated clones.

Klinman, Norman R.

1972-01-01

418

Nano and bulk-silicon-based insertion anodes for lithium-ion secondary cells  

Microsoft Academic Search

The increase in energy density and power density requirements for lithium-ion secondary cells for commercial applications has led to a search for higher capacity electrode materials than those available today. Silicon would seem to be a possible alternative for the graphite or carbon anode because its intercalation capacity is the highest known. However, the large capacity fade observed during initial

Uday Kasavajjula; Chunsheng Wang; A. John Appleby

2007-01-01

419

Development of secondary cell wall in cotton fibers as examined with Fourier transform-infrared spectroscopy  

Technology Transfer Automated Retrieval System (TEKTRAN)

Our presentation will focus on continuing efforts to examine secondary cell wall development in cotton fibers using infrared Spectroscopy. Cotton fibers harvested at 18, 20, 24, 28, 32, 36 and 40 days after flowering were examined using attenuated total reflection Fourier transform-infrared (ATR FT-...

420

CELL PHONES IN NEW ZEALAND SECONDARY SCHOOLS: BOON, BANNED OR BIASED  

Microsoft Academic Search

In this qualitative research study conducted in twelve New Zealand secondary schools data was gathered on policy formation on a range of issues including: cell phone usage at school; mobile technology incorporated into learning; staff development; curriculum development; assessment, school and class management; and registration and enrolment. Participants included: school principals; deans; heads of department; guidance officers; teachers; and prior

K. FIELDEN; P. MALCOLM

2007-01-01

421

Effect of sulfur isotopic composition of zinc and lead sulfides on the E. M. F. of electrochemical cells  

SciTech Connect

A new effect is reported in which unexpectedly large voltages are produced by electrochemical cells containing sulfides at natural isotopic abundance levels. Room temperature experiments were undertaken to determine whether electrochemical cells employing silver bromide and silver beta alumina as solid electrolytes would be sufficiently sensitive to detect small variations in sulfur isotopic composition for zinc and lead sulfides. Voltages obtained for silver bromide cells tended to increase progressively over at least 20 days, and increased in a regular fashion with increasing differences in isotopic composition between charges. Voltages exceeding 150 mV were obtained for /sup delta/S/sup 3,4/ differences up to 85 per mil for zinc sulfide, but reached only about 20 mV for lead sulfide. Silver beta alumina cells with opposing zinc and lead sulfide charges yielded larger voltages and E.M.F. minimum corresponding to a +8(/plus minus/2) per mil difference. This value shows reasonable agreement with interpolated 20/degrees/C equilibrium values of between +7.5 to +9.8 obtained from the literature. Matured silver bromide cells with opposed zinc and lead sulfide charges behaved similarly but yielded lower voltages. Silver concentration cells of the opposed type are thus able to detect isotopic equilibrium and this will permit calibration of sulfur isotope thermometers down to unexpectedly low temperatures.

Lusk, J.; Krouse, H.R.; Batts, B.D.

1988-03-01

422

Electrochemical impedance spectroscopy of dye-sensitized solar cells with thermally degraded N719 loaded TiO2  

NASA Astrophysics Data System (ADS)

Here, we have deliberately degraded N719 loaded TiO2 photoelectrodes (PEs) at elevated temperatures; for example, from 80 °C to 160 °C with a step of 40 °C and studied their influence on photovoltaic parameters of dye-sensitized solar cells (DSSCs). Electrochemical impedance spectroscopy (EIS) study shows that the thermal degraded PEs suffered from increased recombination as well as downward shift of TiO2 conduction band that eventually decreased photovoltage of the cells. In contrast, incident photon-to-current efficiency (IPCE) reveals that poor light harvesting, charge collection and dye regeneration efficiency were responsible for low photocurrent of the DSSCs with thermal degraded PEs.

Sarker, Subrata; Seo, Hyun Woo; Kim, Dong Min

2013-10-01

423

Electrochemical impedance spectra of CdSe quantume dots sensitized nanocrystalline TiO 2 solar cells  

Microsoft Academic Search

Quantum dots sensitized nanocrystalline TiO2 solar cells (QDSSCs) are promising third-generation photovoltaic devices. In comparison with conventional dye-sensitized\\u000a solar cells (DSSCs), the efficiency of QDSSCs is still very low (about 3%). In this paper, the electrochemical impedance spectroscopy\\u000a technology has been adopted to investigate the quasi-Fermi level and the carrier dynamics of the colloidal CdSe QDs sensitized\\u000a TiO2 eletrode with

XueQing Xu; Gang Xu

2011-01-01

424

Dengue Virus Activates Polyreactive, Natural IgG B Cells after Primary and Secondary Infection  

PubMed Central

Background Dengue virus is transmitted by mosquitoes and has four serotypes. Cross-protection to other serotypes lasting for a few months is observed following infection with one serotype. There is evidence that low-affinity T and/or B cells from primary infections contribute to the severe syndromes often associated with secondary dengue infections. such pronounced immune-mediated enhancement suggests a dengue-specific pattern of immune cell activation. This study investigates the acute and early convalescent B cell response leading to the generation of cross-reactive and neutralizing antibodies following dengue infection. Methodology/Principal Findings We assayed blood samples taken from dengue patients with primary or secondary infection during acute disease and convalescence and compared them to samples from patients presenting with non-dengue related fever. Dengue induced massive early plasmablast formation, which correlated with the appearance of polyclonal, cross-reactive IgG for both primary and secondary infection. Surprisingly, the contribution of IgG to the neutralizing titer 4–7 days after fever onset was more than 50% even after primary infection. Conclusions/Significance Poly-reactive and virus serotype cross-reactive IgG are an important component of the innate response in humans during both primary and secondary dengue infection, and “innate specificities” seem to constitute part of the adaptive response in dengue. While of potential importance for protection during secondary infection, cross-reactive B cells will also compete with highly neutralizing B cells and possibly interfere with their development.

Toh, Ying Xiu; Flamand, Marie; Devi, Shamala; Koh, Mickey B.; Hibberd, Martin L.; Ooi, Eng Eong; Low, Jenny G.; Leo, Yee Sin; Gu, Feng; Fink, Katja

2011-01-01

425

Notch-responsive cells initiate the secondary transition in larval zebrafish pancreas  

PubMed Central

Zebrafish provide a highly versatile model in which to study vertebrate development. Many recent studies have elucidated early events in the organogenesis of the zebrafish pancreas; however, several aspects of early endocrine pancreas formation in the zebrafish are not homologous to the mammalian system. To better identify mechanisms of islet formation in the zebrafish, with true homology to those observed in mammals, we have temporally and spatially characterized zebrafish secondary islet formation. As is the case in the mouse, we show that Notch inhibition leads to precocious differentiation of endocrine tissues. Furthermore, we have used transgenic fish expressing fluorescent markers under the control of a Notch-responsive element to observe the precursors of these induced endocrine cells. These pancreatic Notch-responsive cells represent a novel population of putative progenitors that are associated with larval pancreatic ductal epithelium, suggesting functional homology between secondary islet formation in zebrafish and the secondary transition in mammals. We also show that Notch-responsive cells persist in the adult pancreas and possess the classical characteristics of centroacinar cells, a cell type believed to be a multipotent progenitor cell in adult mammalian pancreas.

Parsons, Michael J.; Pisharath, Harshan; Yusuff, Shamila; Moore, John C.; Siekmann, Arndt F.; Lawson, Nathan; Leach, Steven D.

2013-01-01

426

Room Temperature, Electrochemical Generation of Ozone with 50%?Current Efficiency in 0.5M Sulfuric Acid at Cell Voltages?  

Microsoft Academic Search

The electrochemical generation of ozone by Ni\\/Sb-SnO2 anodes immersed in 0.5M H2SO4 was assessed in both flow and recycle systems using the same electrochemical cell. The anodes were found to exhibit current efficiencies of up to 50%?for ozone generation under flow conditions at room temperature, with an optimum mole ratio in the precursor solutions of ca. 500:8:3 Sn:Sb:Ni and optimum

P. A. Christensen; W. F. Lin; H. Christensen; A. Imkum; J. M. Jin; G. Li; C. M. Dyson

2009-01-01

427

Elucidation of electrochemical properties of electrolyte-impregnated micro-porous ceramic films as framework supports in dye-sensitized solar cells  

Microsoft Academic Search

This study investigates the electrochemical properties of electrolyte-impregnated micro-porous ceramic (Al2O3) films as framework supports in dye-sensitized solar cells (DSSCs). A field-emission scanning electron microscope (FE-SEM) is used to characterize the morphology on both surfaces of the ceramic membranes, which exhibit high porosity (41–66%) and an open cylindrical pore structure. Electrochemical impedance analysis reveals that the conductivity of the electrolyte-impregnated

Hseng Shao Chen; Shingjiang Jessie Lue; Yung Liang Tung; Kong Wei Cheng; Fu Yuan Huang; Kuo Chuan Ho

2011-01-01

428

Electrochemical photovoltaic cells/stabilization and optimization of II-VI semiconductors  

SciTech Connect

The overall goal of this program is to provide the basis for designing a practical electrochemical solar cell based on the II-VI compound semiconductors. Emphasis is on developing new electrolyte redox systems and electrode surface modifications which will stabilize the II-VI compounds against photodissolution without seriously degrading the long-term solar response. Factors limiting the short circuit current of the n-CdSe photoanodes in the methanol/ferro-ferricyanide system were identified. Although the methanol/ferro-ferricyanide solution itself was found to be photolytically unstable, study of this system led to the identification of more promising nonaqueous redox electrolytes. Additional work on redox couple stabilizaton of n-CdX photoanodes was focused on both one- and two-electron couples. Very promising results were obtained for the alkylammonium chloro-Fe(II,III) couple in acetonitrile. Conducting polymer films of polypyrrole photoelectrochemically deposited onto n-type semiconductors were shown to protect these electrode materials from photodecomposition while permitting electron exchange with the electrolyte, but poor adhesion has remained a key problem. Recently, improved adhesion has been attained for roughened semiconductor surfaces. In a basic aqueous ferro-ferricyanide electrolyte containing cyanide ion, the measured open circuit voltage for n-CdTe was 1.3 V, which is practically the bandgap for this material. It now appears that polypyrrole films are to some extent permeable to solvent/solute species since the film stability depends on the nature of the redox electrolyte, and semiconductor decomposition products seem to form underneath film in some cases. Some work with polyaniline films was performed. Work on evaluating photocapacitance spectroscopy as a means of in situ characterization of semiconductor electrodes was focused on developing a reliable measurement technique.

Noufi, R.; Tench, D.; Warren, L.

1981-03-01

429

Unexpected large spectral shift from blue to green region in a light-emitting electrochemical cell  

NASA Astrophysics Data System (ADS)

A new, but archetype compound [Ir(ppy-F2)2Me4phen]PF6, where ppy-F2 is 2-(2',4'- fluorophenyl)pyridine and Me4phen is 3,4,7,8-tetramethyl-1,10-phenanthroline, was synthesized and used to prepare a solid-state light-emitting electrochemical cell (LEC). This complex emits blue light with a maximum at 476 nm when photoexcited in a thin film, with a photoluminescence quantum yield of 52 %. It yields an efficient single-component solid-state electroluminescence device with a current efficiency reaching 5.5 cd/A and a maximum power efficiency of 5.8 Lm/Watt. However, the electroluminiscence spectrum is shifted with respect to the photoluminiscence spectrum by 80 nm resulting in the emission of green light. We demonstrate that this unexpected shift in emission spectrum is not originating from the way of excitation, nor from the presence of large concentrations of ions, but is related to the concentration of the ionic transition metal complex in the thin film. The origin of the concentration dependent emission is extensively commented and argued to be related to the population of either 3LC ?-?* or 3MLCT triplet states, in diluted and concentrated films, respectively. Using quantum chemical calculations we demonstrate that three low-energy triplet states are present with only 0.1 eV difference in energy and that their associated emission wavelengths differ by as much as 60 nm from each other.

Bolink, Henk J.; Coronado, Eugenio; Costa, Rubén D.; Lardiés, Nora; Nazeeruddin, Md. K.; Ortí, Enrique

2008-05-01

430

Development of a standard bench-scale cell for electrochemical studies on inert anodes. Inert Anode/Cathode Program  

SciTech Connect

Objective of this work was to develop a standard bench-scale cell for performing short-term ac and dc polarization studies on inert anode candidate materials in molten cryolite. Two designs for electrochemical cells were developed and successfully evaluated in short-term experiments. Both cells consisted on the inert anode as a small cylindrical specimen partially sheathed in alumina, an Al/Al/sub 2/O/sub 3/ reference electrode, and a cryolite bath saturated in alumina. The difference between the two cells was in the design of the cathode. One cell used a bare solid metal cathode; the other used an aluminum pad similar to the Hall-Heroult configuration.

Windisch, C.F. Jr.; Boget, D.I.

1986-07-01

431

Characterization of high-power lithium-ion cells during constant current cycling. Part I. Cycle performance and electrochemical diagnostics  

SciTech Connect

Twelve-cm{sup 2} pouch type lithium-ion cells were assembled with graphite anodes, LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} cathodes and 1M LiPF{sub 6}/EC/DEC electrolyte. These pouch cells were cycled at different depths of discharge (100 percent and 70 percent DOD) at room temperature to investigate cycle performance and pulse power capability. The capacity loss and power fade of the cells cycled over 100 percent DOD was significantly faster than the cell cycled over 70 percent DOD. The overall cell impedance increased with cycling, although the ohmic resistance from the electrolyte was almost constant. From electrochemical analysis of each electrode after cycling, structural and/or impedance changes in the cathode are responsible for most of the capacity and power fade, not the consumption of cycleable Li from side-reactions.

Shim, Joongpyo; Striebel, Kathryn A.

2003-01-24

432

Effect of nano-topographical features of Ti/TiO(2) electrode surface on cell response and electrochemical stability in artificial saliva.  

PubMed

The paper is a new approach which aims to evaluate the relation between surface aspects (wettability and roughness) of materials based on titanium with native passive TiO(2) as untreated samples and TiO(2) nanotubes as treated discs respectively, their electrochemical stability in artificial saliva, and fibroblast cell behavior. Ti/TiO(2) modified electrodes as nanotubes with 120 nm as diameter were obtained using an electrochemical method as anodizing and surface analysis as SEM, AFM and contact angle measurements were performed to obtain topographical features and wettability. The TiO(2) nanotube structured oxide films electrochemical growth increases the stability of titanium surfaces. The electrochemical behavior of the Ti/TiO(2) nanotube surface was evaluated by corrosion parameters obtained from Tafel plots and electrical parameters for proposed circuits from electrochemical impedance spectroscopy were analyzed. The cell results indicated a slight preference in terms of cell survival and adhesion for nanostructure TiO(2) with a more hydrophilic character and the electrochemical data revealed that such features are connected with better stability in artificial saliva. The roughness seems to be not conclusive for this case. PMID:20189888

Demetrescu, I; Pirvu, C; Mitran, V

2010-02-10

433

Cell-mediated cytotoxicity: comparison of primary and secondary immune reactions after parainfluenza type 1 virus inoculation.  

PubMed

H-2 antigen compatibility of effector spleen cells and target cells was necessary for cell-mediated cytotoxicity (CMC) after both 1 and 2 intraperitoneal inoculation of 6/94 virus into mice. T cells were responsible for both primary and secondary CMS reactions. Neither reaction was influenced by the presence of virus-specific antibody added to the test system. Secondary CMC peaked earlier than the primary response and declined more rapidly. In vitro stimulation of primed spleen cells could also be used to detect the secondary CMC response. PMID:202521

Kibler, R; Solvay, M J; ter Meulen, V

1978-01-01

434

MYB75 functions in regulation of secondary cell wall formation in the Arabidopsis inflorescence stem.  

PubMed

Deposition of lignified secondary cell walls in plants involves a major commitment of carbon skeletons in both the form of polysaccharides and phenylpropanoid constituents. This process is spatially and temporally regulated by transcription factors, including a number of MYB family transcription factors. MYB75, also called PRODUCTION OF ANTHOCYANIN PIGMENT1, is a known regulator of the anthocyanin branch of the phenylpropanoid pathway in Arabidopsis (Arabidopsis thaliana), but how this regulation might impact other aspects of carbon metabolism is unclear. We established that a loss-of-function mutation in MYB75 (myb75-1) results in increased cell wall thickness in xylary and interfascicular fibers within the inflorescence stem. The total lignin content and S/G ratio of the lignin monomers were also affected. Transcript profiles from the myb75-1 inflorescence stem revealed marked up-regulation in the expression of a suite of genes associated with lignin biosynthesis and cellulose deposition, as well as cell wall modifying proteins and genes involved in photosynthesis and carbon assimilation. These patterns suggest that MYB75 acts as a repressor of the lignin branch of the phenylpropanoid pathway. Since MYB75 physically interacts with another secondary cell wall regulator, the KNOX transcription factor KNAT7, these regulatory proteins may form functional complexes that contribute to the regulation of secondary cell wall deposition in the Arabidopsis inflorescence stem and that integrate the metabolic flux through the lignin, flavonoid, and polysaccharide pathways. PMID:20807862

Bhargava, Apurva; Mansfield, Shawn D; Hall, Hardy C; Douglas, Carl J; Ellis, Brian E

2010-08-31

435

Use of high-temperature gas-tight electrochemical cells to measure electronic transport and thermodynamics in metal oxides  

SciTech Connect

By using a gas-tight electrochemical cell, the authors can perform high-temperature coulometric titration and measure electronic transport properties to determine the electronic defect structure of metal oxides. This technique reduces the time and expense required for conventional thermogravimetric measurements. The components of the gas-tight coulometric titration cell are an oxygen sensor, Pt/yttria stabilized zirconia (YSZ)/Pt, and an encapsulated metal oxide sample. Based on cell design, both transport and thermodynamic measurements can be performed over a wide range of oxygen partial pressures (pO{sub 2} = 10{sup {minus}35} to 1 atm). This paper describes the high-temperature gas-tight electrochemical cells used to determine electronic defect structures and transport properties for pure and doped-oxide systems, such as YSZ, doped and pure ceria (Ca-CeO{sub 2} and CeO{sub 2}), copper oxides, and copper-oxide-based ceramic superconductors, transition metal oxides, SrFeCo{sub 0.5}O{sub x}, and BaTiO{sub 3}.

Park, J.H.; Ma, B.; Park, E.T. [Argonne National Lab., IL (United States). Energy Technology Div.

1997-10-01

436

Bioreactor production of secondary metabolites from cell cultures of periwinkle and sandalwood.  

PubMed

A bench-top bioreactor allowing continuous extraction of secondary metabolites is designed for Catharanthus roseus L. (G.) Don (periwinkle) and Santalum album L. (sandalwood) plant cell suspensions. Periwinkle cell cultures are exposed to biotic elicitors (Aspergillus niger, crude chitin) and abiotic elicitors (mannitol, methyl jasmonate) to induce alkaloid production. Whereas most of the biotic elicitors are effective when added on day 15 of culture, the abiotic elicitors are effective when added on day 20. The use of trans-cinnamic acid, an inhibitor of phenylalanine ammonia lyase (PAL) activity, results in significant increase in the alkaloid production of periwinkle cell cultures. Exposure of the cells to mannitol-induced osmotic stress produced marked increment in the total alkaloid production. When biotic and abiotic stress treatments are applied sequentially, an additive effect in alkaloid accumulation is observed. Although no essential oils are detected, secondary metabolites in the form of phenolics are produced by the sandalwood cell cultures in the bioreactor environment. The use of morphologic modification such as organ cultures and transformed cultures is believed to be required for both production and storage of essential oil constituents in sandalwood. The present chapter demonstrates that periwinkle and sandalwood cell suspensions could be developed and successfully cultured in a modified air-lift bioreactor. The exploitation of variant cell strains and biotransformation of added precursors can certainly improve the use of periwinkle and sandalwood cell cultures for the bioproduction of desired compounds. PMID:19521856

Valluri, Jagan V

2009-01-01

437

Alternating-polarity operation for complete regeneration of electrochemical deionization system  

DOEpatents

An electrically regeneratable battery of electrochemical cells for capacitive deionization (including electrochemical purification) and regeneration of electrodes is operated at alternate polarities during consecutive cycles. By polarizing the cells, ions are removed from the electrolyte and are held in the electric double layers formed at the carbon aerogel surfaces of the electrodes. As the electrodes of each cell of the battery are saturated with the removed ions, the battery is regenerated electrically at a reversed polarity from that during the deionization step of the cycle, thus significantly minimizing secondary wastes.

Tran, Tri D. (Livermore, CA); Lenz, David J. (Livermore, CA)

2002-01-01

438

Interactions between MUR10\\/CesA7Dependent Secondary Cellulose Biosynthesis and Primary Cell Wall Structure1(OA)  

Microsoft Academic Search

Primary cell walls are deposited and remodeled during cell division and expansion. Secondary cell walls are deposited in specialized cells after the expansion phase. It is presently unknown whether and how these processes are interrelated. The Arabidopsis (Arabidopsis thaliana) MUR10 gene is required for normal primary cell wall carbohydrate composition in mature leaves as well as for normal plant growth,

Sonia Bosca; J. Barton; Neil G. Taylor; Peter Ryden; Markus Pauly; Keith Roberts; Georg J. Seifert

439

Large-scale co-expression approach to dissect secondary cell wall formation across plant species.  

PubMed

Plant cell walls are complex composites largely consisting of carbohydrate-based polymers, and are generally divided into primary and secondary walls based on content and characteristics. Cellulose microfibrils constitute a major component of both primary and secondary cell walls and are synthesized at the plasma membrane by cellulose synthase (CESA) complexes. Several studies in Arabidopsis have demonstrated the power of co-expression analyses to identify new genes associated with secondary wall cellulose biosynthesis. However, across-species comparative co-expression analyses remain largely unexplored. Here, we compared co-expressed gene vicinity networks of primary and secondary wall CESAsin Arabidopsis, barley, rice, poplar, soybean, Medicago, and wheat, and identified gene families that are consistently co-regulated with cellulose biosynthesis. In addition to the expected polysaccharide acting enzymes, we also found many gene families associated with cytoskeleton, signaling, transcriptional regulation, oxidation, and protein degradation. Based on these analyses, we selected and biochemically analyzed T-DNA insertion lines corresponding to approximately twenty genes from gene families that re-occur in the co-expressed gene vicinity networks of secondary wall CESAs across the seven species. We developed a statistical pipeline using principal component analysis and optimal clustering based on silhouette width to analyze sugar profiles. One of the mutants, corresponding to a pinoresinol reductase gene, displayed disturbed xylem morphology and held lower levels of lignin molecules. We propose that this type of large-scale co-expression approach, coupled with statistical analysis of the cell wall contents, will be useful to facilitate rapid knowledge transfer across plant species. PMID:22639584

Ruprecht, Colin; Mutwil, Marek; Saxe, Friederike; Eder, Michaela; Nikoloski, Zoran; Persson, Staffan

2011-07-01

440

Large-Scale Co-Expression Approach to Dissect Secondary Cell Wall Formation Across Plant Species  

PubMed Central

Plant cell walls are complex composites largely consisting of carbohydrate-based polymers, and are generally divided into primary and secondary walls based on content and characteristics. Cellulose microfibrils constitute a major component of both primary and secondary cell walls and are synthesized at the plasma membrane by cellulose synthase (CESA) complexes. Several studies in Arabidopsis have demonstrated the power of co-expression analyses to identify new genes associated with secondary wall cellulose biosynthesis. However, across-species comparative co-expression analyses remain largely unexplored. Here, we compared co-expressed gene vicinity networks of primary and secondary wall CESAsin Arabidopsis, barley, rice, poplar, soybean, Medicago, and wheat, and identified gene families that are consistently co-regulated with cellulose biosynthesis. In addition to the expected polysaccharide acting enzymes, we also found many gene families associated with cytoskeleton, signaling, transcriptional regulation, oxidation, and protein degradation. Based on these analyses, we selected and biochemically analyzed T-DNA insertion lines corresponding to approximately twenty genes from gene families that re-occur in the co-expressed gene vicinity networks of secondary wall CESAs across the seven species. We developed a statistical pipeline using principal component analysis and optimal clustering based on silhouette width to analyze sugar profiles. One of the mutants, corresponding to a pinoresinol reductase gene, displayed disturbed xylem morphology and held lower levels of lignin molecules. We propose that this type of large-scale co-expression approach, coupled with statistical analysis of the cell wall contents, will be useful to facilitate rapid knowledge transfer across plant species.

Ruprecht, Colin; Mutwil, Marek; Saxe, Friederike; Eder, Michaela; Nikoloski, Zoran; Persson, Staffan

2011-01-01