Sample records for electrically conductive refractory
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Control for monitoring thickness of high temperature refractory
Caines, M.J.
1982-11-23
This invention teaches an improved monitoring device for detecting the changes in thickness of high-temperature refractory, the device consists of a probe having at least two electrically conductive generally parallel elements separated by a dielectric material. The probe is implanted or embedded directly in the refractory and is elongated to extend in line with the refractory thickness to be measured. Electrical inputs to the conductive elements provide that either or both the electrical conductance or capacitance can be found, so that charges over lapsed time periods can be compared in order to detect changes in the thickness of the refractory.
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Refractory electrodes for joule heating and methods of using same
Lamar, David A.; Chapman, Chris C.; Elliott, Michael L.
1998-01-01
A certain group of electrically conductive refractory materials presently known for use in high temperature applications as throat constructions, melter sidewalls, forehearth, stacks, port sills, hot face lining for slagging coal gasifiers, slag runners, and linings for nuclear waste encapsulation furnaces may be used as electrodes permitting joule heating at temperatures in excess of 1200 C. in excess of about 4400 hours even in the presence of transition group element(s). More specifically, the invention is an electrode for melting earthen materials, wherein the electrode is made from an electrically conductive refractory material, specifically at least one metal oxide wherein the metal is selected from the group consisting of chrome, ruthenium, rhodium, tin and combinations thereof.
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Refractory electrodes for joule heating and methods of using same
Lamar, D.A.; Chapman, C.C.; Elliott, M.L.
1998-05-12
A certain group of electrically conductive refractory materials presently known for use in high temperature applications as throat constructions, melter sidewalls, forehearth, stacks, port sills, hot face lining for slagging coal gasifiers, slag runners, and linings for nuclear waste encapsulation furnaces may be used as electrodes permitting joule heating at temperatures in excess of 1,200 C in excess of about 4400 hours even in the presence of transition group element(s). More specifically, the invention is an electrode for melting earthen materials, wherein the electrode is made from an electrically conductive refractory material, specifically at least one metal oxide wherein the metal is selected from the group consisting of chrome, ruthenium, rhodium, tin and combinations thereof. 2 figs.
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Compatibility Studies of Various Refractory Materials in Contact with Molten Silicon
NASA Technical Reports Server (NTRS)
Odonnell, T.; Leipold, M. H.; Hagan, M.
1978-01-01
The production of low cost, efficient solar cells for terrestrial electric power generation involves the manipulation of molten silicon with a present need for noncontaminating, high temperature refractories to be used as containment vessels, ribbon-production dies, and dip-coated substrates. Studies were conducted on the wetting behavior and chemical/physical interactions between molten silicon and various refractory materials.
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Refractory lining for electrochemical cell
Blander, Milton; Cook, Glenn M.
1987-01-01
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 contcat 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.
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Steel refining with an electrochemical cell
Blander, M.; Cook, G.M.
1988-05-17
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.
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Steel refining with an electrochemical cell
Blander, M.; Cook, G.M.
1985-05-21
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.
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Steel refining with an electrochemical cell
Blander, Milton; Cook, Glenn M.
1988-01-01
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.
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Oxygen sensitive, refractory oxide composition
Holcombe, Jr., Cressie E.; Smith, Douglas D.
1976-01-01
Oxide compositions containing niobium pentoxide and an oxide selected from the group consisting of hafnia, titania, and zirconia have electrical conductivity characteristics which vary greatly depending on the oxygen content.
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Refractory Research Group - U.S. DOE, Albany Research Center [Institution Profile
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bennett, James P.
2004-09-01
The refractory research group at the Albany Research Center (ARC) has a long history of conducting materials research within the U.S. Bureau of Mines, and more recently, within the U.S. Dept. of Energy. When under the U.S. Bureau of Mines, research was driven by national needs to develop substitute materials and to conserve raw materials. This mission was accomplished by improving refractory material properties and/or by recycling refractories using critical and strategic materials. Currently, as a U.S. Dept of Energy Fossil Energy field site, research is driven primarily by the need to assist DOE in meeting its vision to developmore » economically and environmentally viable technologies for the production of electricity from fossil fuels. Research at ARC impacts this vision by: • Providing information on the performance characteristics of materials being specified for the current generation of power systems; • Developing cost-effective, high performance materials for inclusion in the next generation of fossil power systems; and • Solving environmental emission and waste problems related to fossil energy systems. A brief history of past refractory research within the U.S. Bureau of Mines, the current refractory research at ARC, and the equipment and capabilities used to conduct refractory research at ARC will be discussed.« less
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Reuse of ultrafine mineral wool production waste in the manufacture of refractory concrete.
Stonys, R; Kuznetsov, D; Krasnikovs, A; Škamat, J; Baltakys, K; Antonovič, V; Černašėjus, O
2016-07-01
The paper deals with the mineral wool production waste (cupola dust - CD), presents CD characterization and aims to reuse CD in production of refractory concrete with calcium aluminate cement. The study of CD covers its chemical, phase and thermal analyses along with the morphological study and determination of particles size distribution. Zeta-potential, electrical conductivity and pH values of CD suspension are presented in the paper as well. Commercial microsilica additive in refractory concrete has been replaced with cupola dust. Compositions of refractory concrete have been prepared by incorporating 1%, 2% and 3% of CD. The bulk density, ultrasonic wave velocity, cold crushing strength and thermal shock resistance of the created refractory concrete have been determined. Based on experimental results, it has been found that cupola dust may be used for the production of refractory concrete. The environmental impact related to the CD reuse in refractory concrete production has been evaluated as well. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Khan, Muhammad Sadiq Ali; Yousuf, Sidrah
2016-03-01
Cardiac Electrical Activity is commonly distributed into three dimensions of Cardiac Tissue (Myocardium) and evolves with duration of time. The indicator of heart diseases can occur randomly at any time of a day. Heart rate, conduction and each electrical activity during cardiac cycle should be monitor non-invasively for the assessment of "Action Potential" (regular) and "Arrhythmia" (irregular) rhythms. Many heart diseases can easily be examined through Automata model like Cellular Automata concepts. This paper deals with the different states of cardiac rhythms using cellular automata with the comparison of neural network also provides fast and highly effective stimulation for the contraction of cardiac muscles on the Atria in the result of genesis of electrical spark or wave. The specific formulated model named as "States of automaton Proposed Model for CEA (Cardiac Electrical Activity)" by using Cellular Automata Methodology is commonly shows the three states of cardiac tissues conduction phenomena (i) Resting (Relax and Excitable state), (ii) ARP (Excited but Absolutely refractory Phase i.e. Excited but not able to excite neighboring cells) (iii) RRP (Excited but Relatively Refractory Phase i.e. Excited and able to excite neighboring cells). The result indicates most efficient modeling with few burden of computation and it is Action Potential during the pumping of blood in cardiac cycle.
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Wire EDM for Refractory Materials
NASA Technical Reports Server (NTRS)
Zellars, G. R.; Harris, F. E.; Lowell, C. E.; Pollman, W. M.; Rys, V. J.; Wills, R. J.
1982-01-01
In an attempt to reduce fabrication time and costs, Wire Electrical Discharge Machine (Wire EDM) method was investigated as tool for fabricating matched blade roots and disk slots. Eight high-strength nickel-base superalloys were used. Computer-controlled Wire EDM technique provided high quality surfaces with excellent dimensional tolerances. Wire EDM method offers potential for substantial reductions in fabrication costs for "hard to machine" alloys and electrically conductive materials in specific high-precision applications.
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Electrochemical cell with powdered electrically insulative material as a separator
Mathers, James P.; Olszanski, Theodore W.; Boquist, Carl W.
1978-01-01
A secondary electrochemical cell includes electrodes separated by a layer of electrically insulative powder. The powder includes refractory materials selected from the oxides and nitrides of metals and metaloids. The powdered refractory material, blended with electrolyte particles, can be compacted in layers with electrode materials to form an integral electrode structure or separately assembled into the cell. The assembled cell is heated to operating temperature leaving porous layers of electrically insulative, refractory particles, containing molten electrolyte between the electrodes.
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Method of preparing a powdered, electrically insulative separator for use in an electrochemical cell
Cooper, Tom O.; Miller, William E.
1978-01-01
A secondary electrochemical cell includes electrodes separated by a layer of electrically insulative powder. The powder includes refractory materials selected from the oxides and nitrides of metals and metaloids. The powdered refractory material, blended with electrolyte particles, is compacted as layers onto an electrode to form an integral electrode structure and assembled into the cell. The assembled cell is heated to its operating temperature leaving porous layers of electrically insulative, refractory particles, containing molten electrolyte between the electrodes.
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Dofetilide promotes repolarization abnormalities in perfused Guinea-pig heart.
Osadchii, Oleg E
2012-12-01
Dofetilide is class III antiarrhythmic agent which prolongs cardiac action potential duration because of selective inhibition of I (Kr), the rapid component of the delayed rectifier K(+) current. Although clinical studies reported on proarrhythmic risk associated with dofetilide treatment, the contributing electrophysiological mechanisms remain poorly understood. This study was designed to determine if dofetilide-induced proarrhythmia may be attributed to abnormalities in ventricular repolarization and refractoriness. The monophasic action potential duration and effective refractory periods (ERP) were assessed at distinct epicardial and endocardial sites along with volume-conducted ECG recordings in isolated, perfused guinea-pig heart preparations. Dofetilide was found to produce the reverse rate-dependent prolongation of ventricular repolarization, increased the steepness of action potential duration rate adaptation, and amplified transepicardial variability in electrical restitution kinetics. Dofetilide also prolonged the T peak-to-end interval on ECG, and elicited a greater prolongation of endocardial than epicardial ERP, thereby increasing transmural dispersion of refractoriness. At epicardium, dofetilide prolonged action potential duration to a greater extent than ERP, thus extending the critical interval for ventricular re-excitation. This change was associated with triangulation of epicardial action potential because of greater dofetilide-induced prolonging effect at 90 % than 30 % repolarization. Premature ectopic beats and spontaneous short-lasting episodes of monomorphic ventricular tachycardia were observed in 44 % of dofetilide-treated heart preparations. Proarrhythmic potential of dofetilide in guinea-pig heart is attributed to steepened electrical restitution, increased transepicardial variability in electrical restitution kinetics, amplified transmural dispersion of refractoriness, increased critical interval for ventricular re-excitation, and triangulation of epicardial action potential.
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Forming Refractory Insulation On Copper Wire
NASA Technical Reports Server (NTRS)
Setlock, J.; Roberts, G.
1995-01-01
Alternative insulating process forms flexible coat of uncured refractory insulating material on copper wire. Coated wire formed into coil or other complex shape. Wire-coating apparatus forms "green" coat on copper wire. After wire coiled, heating converts "green" coat to refractory electrical insulator. When cured to final brittle form, insulating material withstands temperatures above melting temperature of wire. Process used to make coils for motors, solenoids, and other electrical devices to be operated at high temperatures.
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High-Temperature Hall-Effect Apparatus
NASA Technical Reports Server (NTRS)
Wood, C.; Lockwood, R. A.; Chemielewski, A. B.; Parker, J. B.; Zoltan, A.
1985-01-01
Compact furnace minimizes thermal gradients and electrical noise. Semiautomatic Hall-effect apparatus takes measurements on refractory semiconductors at temperatures as high as 1,100 degrees C. Intended especially for use with samples of high conductivity and low chargecarrier mobility that exhibit low signal-to-noise ratios, apparatus carefully constructed to avoid spurious electromagnetic and thermoelectric effects that further degrade measurements.
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A time dependent anatomically detailed model of cardiac conduction
NASA Technical Reports Server (NTRS)
Saxberg, B. E.; Grumbach, M. P.; Cohen, R. J.
1985-01-01
In order to understand the determinants of transitions in cardiac electrical activity from normal patterns to dysrhythmias such as ventricular fibrillation, we are constructing an anatomically and physiologically detailed finite element simulation of myocardial electrical propagation. A healthy human heart embedded in paraffin was sectioned to provide a detailed anatomical substrate for model calculations. The simulation of propagation includes anisotropy in conduction velocity due to fiber orientation as well as gradients in conduction velocities, absolute and relative refractory periods, action potential duration and electrotonic influence of nearest neighbors. The model also includes changes in the behaviour of myocardial tissue as a function of the past local activity. With this model, we can examine the significance of fiber orientation and time dependence of local propagation parameters on dysrhythmogenesis.
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Sweet, Jennifer A; Mitchell, Laura S; Narouze, Samer; Sharan, Ashwini D; Falowski, Steven M; Schwalb, Jason M; Machado, Andre; Rosenow, Joshua M; Petersen, Erika A; Hayek, Salim M; Arle, Jeffrey E; Pilitsis, Julie G
2015-09-01
Occipital neuralgia (ON) is a disorder characterized by sharp, electrical, paroxysmal pain, originating from the occiput and extending along the posterior scalp, in the distribution of the greater, lesser, and/or third occipital nerve. Occipital nerve stimulation (ONS) constitutes a promising therapy for medically refractory ON because it is reversible with minimal side effects and has shown continued efficacy with long-term follow-up. To conduct a systematic literature review and provide treatment recommendations for the use of ONS for the treatment of patients with medically refractory ON. A systematic literature search was conducted using the PubMed database and the Cochrane Library to locate articles published between 1966 and April 2014 using MeSH headings and keywords relevant to ONS as a means to treat ON. A second literature search was conducted using the PubMed database and the Cochrane Library to locate articles published between 1966 and June 2014 using MeSH headings and keywords relevant to interventions that predict response to ONS in ON. The strength of evidence of each article that underwent full text review and the resulting strength of recommendation were graded according to the guidelines development methodology of the American Association of Neurological Surgeons/Congress of Neurological Surgeons Joint Guidelines Committee. Nine studies met the criteria for inclusion in this guideline. All articles provided Class III Level evidence. Based on the data derived from this systematic literature review, the following Level III recommendation can be made: the use of ONS is a treatment option for patients with medically refractory ON.
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Sánchez, Carlos; Corrias, Alberto; Bueno-Orovio, Alfonso; Davies, Mark; Swinton, Jonathan; Jacobson, Ingemar; Laguna, Pablo; Pueyo, Esther; Rodríguez, Blanca
2012-03-01
Pharmacological treatment of atrial fibrillation (AF) exhibits limited efficacy. Further developments require a comprehensive characterization of ionic modulators of electrophysiology in human atria. Our aim is to systematically investigate the relative importance of ionic properties in modulating excitability, refractoriness, and rotor dynamics in human atria before and after AF-related electrical remodeling (AFER). Computer simulations of single cell and tissue atrial electrophysiology were conducted using two human atrial action potential (AP) models. Changes in AP, refractory period (RP), conduction velocity (CV), and rotor dynamics caused by alterations in key properties of all atrial ionic currents were characterized before and after AFER. Results show that the investigated human atrial electrophysiological properties are primarily modulated by maximal value of Na(+)/K(+) pump current (G(NaK)) as well as conductances of inward rectifier potassium current (G(K1)) and fast inward sodium current (G(Na)). G(NaK) plays a fundamental role through both electrogenic and homeostatic modulation of AP duration (APD), APD restitution, RP, and reentrant dominant frequency (DF). G(K1) controls DF through modulation of AP, APD restitution, RP, and CV. G(Na) is key in determining DF through alteration of CV and RP, particularly in AFER. Changes in ionic currents have qualitatively similar effects in control and AFER, but effects are smaller in AFER. The systematic analysis conducted in this study unravels the important role of the Na(+)/K(+) pump current in determining human atrial electrophysiology.
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Bergman, Werner
1986-01-01
An electric disk filter provides a high efficiency at high temperature. A hollow outer filter of fibrous stainless steel forms the ground electrode. A refractory filter material is placed between the outer electrode and the inner electrically isolated high voltage electrode. Air flows through the outer filter surfaces through the electrified refractory filter media and between the high voltage electrodes and is removed from a space in the high voltage electrode.
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Bergman, W.
1985-01-09
An electric disk filter provides a high efficiency at high temperature. A hollow outer filter of fibrous stainless steel forms the ground electrode. A refractory filter material is placed between the outer electrode and the inner electrically isolated high voltage electrode. Air flows through the outer filter surfaces through the electrified refractory filter media and between the high voltage electrodes and is removed from a space in the high voltage electrode.
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A review of refractory materials for vapor-anode AMTEC cells
NASA Astrophysics Data System (ADS)
King, Jeffrey C.; El-Genk, M. S.
2000-01-01
Recently, refractory alloys have been considered as structural materials for vapor-anode Alkali Metal Thermal-to-Electric Conversion (AMTEC) cells, for extended (7-15 years) space missions. This paper reviewed the existing database for refractory metals and alloys of potential use as structural materials for vapor-anode sodium AMTEC cells. In addition to requiring that the vapor pressure of the material be below 10-9 torr (133 nPa) at a typical hot side temperature of 1200 K, other screening considerations were: (a) low thermal conductivity, low thermal radiation emissivity, and low linear thermal expansion coefficient; (b) low ductile-to-brittle transition temperature, high yield and rupture strengths and high strength-to-density ratio; and (c) good compatibility with the sodium AMTEC operating environment, including high corrosion resistance to sodium in both the liquid and vapor phases. Nb-1Zr (niobium-1% zirconium) alloy is recommended for the hot end structures of the cell. The niobium alloy C-103, which contains the oxygen gettering elements zirconium and hafnium as well as titanium, is recommended for the colder cell structure. This alloy is stronger and less thermally conductive than Nb-1Zr, and its use in the cell wall reduces parasitic heat losses by conduction to the condenser. The molybdenum alloy Mo-44.5Re (molybdenum-44.5% rhenium) is also recommended as a possible alternative for both structures if known problems with oxygen pick up and embrittlement of the niobium alloys proves to be intractable. .
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Electromagnetic valve for controlling the flow of molten, magnetic material
Richter, T.
1998-06-16
An electromagnetic valve for controlling the flow of molten, magnetic material is provided, which comprises an induction coil for generating a magnetic field in response to an applied alternating electrical current, a housing, and a refractory composite nozzle. The nozzle is comprised of an inner sleeve composed of an erosion resistant refractory material (e.g., a zirconia ceramic) through which molten, magnetic metal flows, a refractory outer shell, and an intermediate compressible refractory material, e.g., unset, high alumina, thermosetting mortar. The compressible refractory material is sandwiched between the inner sleeve and outer shell, and absorbs differential expansion stresses that develop within the nozzle due to extreme thermal gradients. The sandwiched layer of compressible refractory material prevents destructive cracks from developing in the refractory outer shell. 5 figs.
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Electromagnetic valve for controlling the flow of molten, magnetic material
Richter, Tomas
1998-01-01
An electromagnetic valve for controlling the flow of molten, magnetic material is provided, which comprises an induction coil for generating a magnetic field in response to an applied alternating electrical current, a housing, and a refractory composite nozzle. The nozzle is comprised of an inner sleeve composed of an erosion resistant refractory material (e.g., a zirconia ceramic) through which molten, magnetic metal flows, a refractory outer shell, and an intermediate compressible refractory material, e.g., unset, high alumina, thermosetting mortar. The compressible refractory material is sandwiched between the inner sleeve and outer shell, and absorbs differential expansion stresses that develop within the nozzle due to extreme thermal gradients. The sandwiched layer of compressible refractory material prevents destructive cracks from developing in the refractory outer shell.
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Murata, Hiroshige; Miyauchi, Yasushi; Hayashi, Meiso; Iwasaki, Yu-Ki; Yodogawa, Kenji; Ueno, Akira; Hayashi, Hiroshi; Tsuboi, Ippei; Uetake, Shunsuke; Takahashi, Kenta; Yamamoto, Teppei; Maruyama, Mitsunori; Akutsu, Koichi; Yamamoto, Takeshi; Kobayashi, Yoshinori; Tanaka, Keiji; Atarashi, Hirotsugu; Katoh, Takao; Shimizu, Wataru
2015-01-01
Few reports are available on the characteristics of electrical storms of ventricular tachycardia (VT storm) refractory to intravenous (IV) amiodarone. IV-amiodarone was administered to 60 patients with ventricular tachyarrhythmia between 2007 and 2012. VT storms, defined as 3 or more episodes of VT within 24 h, occurred in 30 patients (68±12 years, 7 female), with 12 having ischemic and 18 non-ischemic heart disease. We compared the clinical and electrocardiographic characteristics of the patients with VT storms suppressed by IV-amiodarone (Effective group) to those of patients not affected by the treatment (Refractory group). IV-amiodarone could not control recurrence of VT in 9 patients (30%). The Refractory group comprised 5 patients with acute myocardial infarctions. Although there was no difference in the VT cycle length, the QRS duration of both the VT and premature ventricular contractions (PVCs) followed by VT was narrower in the Refractory group than in the Effective group (140±30 vs. 178±25 ms, P<0.01; 121±14 vs. 179±22 ms, P<0.01). In the Refractory group, additional administration of IV-mexiletine and/or Purkinje potential-guided catheter ablation was effective. IV-amiodarone-refractory VT exhibited a relatively narrow QRS tachycardia. The narrow triggering PVCs, suggesting a Purkinje fiber origin, may be treated by additional IV-mexiletine and endocardial catheter ablation.
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Bio-heat transfer model of deep brain stimulation-induced temperature changes
NASA Astrophysics Data System (ADS)
Elwassif, Maged M.; Kong, Qingjun; Vazquez, Maribel; Bikson, Marom
2006-12-01
There is a growing interest in the use of chronic deep brain stimulation (DBS) for the treatment of medically refractory movement disorders and other neurological and psychiatric conditions. Fundamental questions remain about the physiologic effects of DBS. Previous basic research studies have focused on the direct polarization of neuronal membranes by electrical stimulation. The goal of this paper is to provide information on the thermal effects of DBS using finite element models to investigate the magnitude and spatial distribution of DBS-induced temperature changes. The parameters investigated include stimulation waveform, lead selection, brain tissue electrical and thermal conductivities, blood perfusion, metabolic heat generation during the stimulation and lead thermal conductivity/heat dissipation through the electrode. Our results show that clinical DBS protocols will increase the temperature of surrounding tissue by up to 0.8 °C depending on stimulation/tissue parameters.
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Refractory metals for ARPS AMTEC cells
DOE Office of Scientific and Technical Information (OSTI.GOV)
Svedberg, R.C.; Sievers, R.C.
1998-07-01
Alkali Metal Thermal-to-Electric Converter (AMTEC) cells for the Advanced Radioisotope Power Systems (ARPS) program are being developed with refractory metals and alloys as the basic structural materials. AMTEC cell efficiency increases with cell operating temperature. For space applications, long term reliability and high efficiency are essential and refractory metals were selected because of their high temperature strength, low vapor pressure, and compatibility with sodium. However, refractory metals are sensitive to oxygen, nitrogen and hydrogen contamination and refractory metal cells cannot be processed in air. Because of this sensitivity, new manufacturing and processing techniques are being developed. In addition to structuralmore » elements, development of other refractory metal components for the AMTEC cells, such as the artery and evaporator wicks, pinchoff tubes and feedthroughs are required. Changes in cell fabrication techniques and processing procedures being implemented to manufacture refractory metal cells are discussed.« less
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Noszczyk-Nowak, Agnieszka; Cepiel, Alicja; Janiszewski, Adrian; Pasławski, Robert; Gajek, Jacek; Pasławska, Urszula; Nicpoń, Józef
2016-01-01
Swine are a well-recognized animal model for human cardiovascular diseases. Despite the widespread use of porcine model in experimental electrophysiology, still no reference values for intracardiac electrical activity and conduction parameters determined during an invasive electrophysiology study (EPS) have been developed in this species thus far. The aim of the study was to develop a set of normal values for intracardiac electrical activity and conduction parameters determined during an invasive EPS of swine. The study included 36 healthy domestic swine (24-40 kg body weight). EPS was performed under a general anesthesia with midazolam, propofol and isoflurane. The reference values for intracardiac electrical activity and conduction parameters were calculated as arithmetic means ± 2 standard deviations. The reference values were determined for AH, HV and PA intervals, interatrial conduction time at its own and imposed rhythm, sinus node recovery time (SNRT), corrected sinus node recovery time (CSNRT), anterograde and retrograde Wenckebach points, atrial, atrioventricular node and ventricular refractory periods. No significant correlations were found between body weight and heart rate of the examined pigs and their electrophysiological parameters. The hereby presented reference values can be helpful in comparing the results of various studies, as well as in more accurately estimating the values of electrophysiological parameters that can be expected in a given experiment.
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40 CFR 420.41 - Specialized definitions.
Code of Federal Regulations, 2011 CFR
2011-07-01
...) [Reserved] (c) The term electric arc furnace steelmaking means the production of steel principally from steel scrap and fluxes in refractory lined furnaces by passing an electric current through the scrap or...
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40 CFR 420.41 - Specialized definitions.
Code of Federal Regulations, 2012 CFR
2012-07-01
... adding oxygen. (b) [Reserved] (c) The term electric arc furnace steelmaking means the production of steel principally from steel scrap and fluxes in refractory lined furnaces by passing an electric current through...
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40 CFR 420.41 - Specialized definitions.
Code of Federal Regulations, 2014 CFR
2014-07-01
...) [Reserved] (c) The term electric arc furnace steelmaking means the production of steel principally from steel scrap and fluxes in refractory lined furnaces by passing an electric current through the scrap or...
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40 CFR 420.41 - Specialized definitions.
Code of Federal Regulations, 2013 CFR
2013-07-01
...) [Reserved] (c) The term electric arc furnace steelmaking means the production of steel principally from steel scrap and fluxes in refractory lined furnaces by passing an electric current through the scrap or...
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George, Sharon A; Faye, N Rokhaya; Murillo-Berlioz, Alejandro; Lee, K Benjamin; Trachiotis, Gregory D; Efimov, Igor R
2017-01-01
The atrioventricular node (AVN) is a complex structure that performs a variety of functions in the heart. The AVN is primarily an electrical gatekeeper between the atria and ventricles and introduces a delay between atrial and ventricular excitation, allowing for efficient ventricular filling. The AVN is composed of several compartments that safely transmit electrical excitation from the atria to the ventricles via the fast or slow pathways. There are many electrophysiological differences between these pathways, including conduction time and electrical refractoriness, that increase the predisposition of the atrioventricular junction to arrhythmias such as atrioventricular nodal re-entrant tachycardia. These varied electrophysiological characteristics of the fast and slow pathways stem from their unique structural and molecular composition (tissue and cellular geometry, ion channels and gap junctions). This review summarises the structural and molecular heterogeneities of the human AVN and how they result in electrophysiological variations and arrhythmias. PMID:29326832
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Bennett, J.P.; Kwong, K.S.; Clark, J.A.
1996-12-31
The Albany Research Center is conducting work on spent refractory recycling/alternate use, including a review of refractory usage and current recycling/disposal practices. Research has focused on the hazardous nature of some spent refractory materials, with emphasis on lead pickup. Information on the issues associated with the reuse of spent refractories will be presented, including those associated with hazardous materials.
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Demonstrating Electrical Activity in Nerve and Muscle. Part I
ERIC Educational Resources Information Center
Robinson, D. J.
1975-01-01
Describes a demonstration for showing the electrical activity in nerve and muscle including action potentials, refractory period of a nerve, and fatigue. Presents instructions for constructing an amplifier, electronic stimulator, and force transducer. (GS)
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Conduction velocity and refractory period of single motor nerve fibres in antecedent poliomyelitis.
Borg, K; Borg, J
1987-01-01
The axonal conduction velocity and the axonal refractory period were determined using electromyographic techniques for 60 single motor units in 11 patients with antecedent poliomyelitis. The results were compared with previous observations in healthy subjects as well as subjects with motor neuron disease. In antecedent poliomyelitis there was a reduced proportion of nerve fibres with low conduction velocity as compared with the findings in healthy subjects. The mean value of the axonal conduction velocities in antecedent poliomyelitis (42.4 +/- 3.7 m/s, M +/- SD) was significantly higher (p less than 0.01) while in motor neuron disease the corresponding value (35.2 +/- 7.8 m/s) was significantly lower (p less than 0.005) than in healthy subjects (39.8 +/- 4.9 m/s). In antecedent poliomyelitis the conduction velocity and refractory period were related as in healthy subjects while abnormally long refractory periods were observed in motor neuron disease. Images PMID:3585356
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Ma, R Y; Li, W; Jiang, X J
2016-12-01
Objective: To investigate the correlation between the site of prelingual cochlear stimulation and its effect on electrically evoked compound action potentials. Method: Recordings of auditory nerve responses were conducted in 32 prelingual subjects to demonstrate the feasibility of ECAP recordings using the nerve response telemetry(NRT) feature of the Nucleus CI24R(CA) system software. These recordings were then analyzed based on the site of cochlear stimulation defined as basal, middle and apical to determine if the amplitude, threshold and slope of the amplitude growth function and the refractory time differs depending on the region of stimulation. Result: Findings of our prelingual children showed significant differences in the ECAP recordings depending on the stimulation site. Comparing the apical with the basal region, on average higher amplitudes, lower thresholds and steeper slopes of the amplitude growth function hadbeen observed. The refractory time showed an overall dependence on cochlear region; however post-hoc tests showed no significant effect between individual regions. Conclusion: Obtaining ECAP recordings is also possible in the most apical region of the cochlea. However, differences can be observed depending on the region of the cochlea stimulated. Specifically, significant higher ECAP amplitude, lower thresholds and steeper amplitude growth function slopes have been observed in the apical region. These differences between prelingual children and adults could be explained by the location of the stimulating electrode with respect to the neural tissue in the cochlea, a higher density, or an increased neural survival rate of neural tissue in the apex. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.
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Microwave Measurement of Refractory Materials at High-Temperature
NASA Astrophysics Data System (ADS)
Kharkovsky, S.; Zoughi, R.; Smith, J.; Davis, B.; Limmer, R.
2009-03-01
Knowledge of the electrical behavior of refractory materials may enable the development and optimization of microwave nondestructive techniques to detect and evaluate changes in their physical properties while the materials are in service. This paper presents the results of a limited and preliminary investigation in which two refractory materials (dense chrome and dense zircon) were subjected to increasing temperature in a furnace and in which a frequency-modulated continuous-wave radar operating in the frequency range of 8-18 GHz radar was used to evaluate their attenuation properties.
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Refractory metal alloys and composites for space nuclear power systems
NASA Technical Reports Server (NTRS)
Titran, Robert H.; Stephens, Joseph R.; Petrasek, Donald W.
1988-01-01
Space power requirements for future NASA and other U.S. missions will range from a few kilowatts to megawatts of electricity. Maximum efficiency is a key goal of any power system in order to minimize weight and size so that the Space Shuttle may be used a minimum number of times to put the power supply into orbit. Nuclear power has been identified as the primary power source to meet these high levels of electrical demand. One method to achieve maximum efficiency is to operate the power supply, energy conservation system, and related components at relatively high temperatures. For systems now in the planning stages, design temperatures range from 1300 K for the immediate future to as high as 1700 K for the advanced systems. NASA Lewis Research Center has undertaken a research program on advanced technology of refractory metal alloys and composites that will provide baseline information for space power systems in the 1900's and the 21st century. Special emphasis is focused on the refractory metal alloys of niobium and on the refractory metal composites which utilize tungsten alloy wires for reinforcement. Basic research on the creep and creep-rupture properties of wires, matrices, and composites are discussed.
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Holmes, Jeffrey W.; Laksman, Zachary; Gepstein, Lior
2015-01-01
Following myocardial infarction (MI), damaged myocytes are replaced by collagenous scar tissue, which serves an important mechanical function – maintaining integrity of the heart wall against enormous mechanical forces – but also disrupts electrical function as structural and electrical remodeling in the infarct and borderzone predispose to re-entry and ventricular tachycardia. Novel emerging regenerative approaches aim to replace this scar tissue with viable myocytes. Yet an alternative strategy of therapeutically modifying selected scar properties may also prove important, and in some cases may offer similar benefits with lower risk or regulatory complexity. Here, we review potential goals for such modifications as well as recent proof-of-concept studies employing specific modifications, including gene therapy to locally increase conduction velocity or prolong the refractory period in and around the infarct scar, and modification of scar anisotropy to improve regional mechanics and pump function. Another advantage of scar modification techniques is that they have applications well beyond MI. In particular, ablation treats electrical abnormalities of the heart by intentionally generating scar to block aberrant conduction pathways. Yet in diseases such as atrial fibrillation (AF) where ablation can be extensive, treating the electrical disorder can significantly impair mechanical function. Creating smaller, denser scars that more effectively block conduction, and choosing the location of those lesions by balancing their electrical and mechanical impacts, could significantly improve outcomes for AF patients. We review some recent advances in this area, including the use of computational models to predict the mechanical effects of specific lesion sets and gene therapy for functional ablation. Overall, emerging techniques for modifying scar properties represents a potentially important important set of tools for improving patient outcomes across a range of heart diseases, whether used in place of or as an adjunct to regenerative approaches. PMID:26615948
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Electrical remodelling of the left and right atria due to rheumatic mitral stenosis.
John, Bobby; Stiles, Martin K; Kuklik, Pawel; Chandy, Sunil T; Young, Glenn D; Mackenzie, Lorraine; Szumowski, Lukasz; Joseph, George; Jose, Jacob; Worthley, Stephen G; Kalman, Jonathan M; Sanders, Prashanthan
2008-09-01
To characterize the atrial remodelling in mitral stenosis (MS). Twenty-four patients with severe MS undergoing commissurotomy and 24 controls were studied. Electrophysiological evaluation was performed in 12 patients in each group by positioning multi-electrode catheters in both atria to determine the following: effective refractory period (ERP) at 10 sites at 600 and 450 ms; conduction time; conduction delay at the crista terminalis (CT); and vulnerability for atrial fibrillation (AF). P-wave duration (PWD) was determined on the surface ECG. In the remaining 12 patients in each group, electroanatomic maps of both atria were created to determine conduction velocity and identify regions of low voltage and electrical silence. Patients with MS had larger left atria (LA) (P < 0.0001); prolonged PWD (P = 0.0007); prolonged ERP in both LA (P < 0.0001) and right atria (RA) (P < 0.0001); reduced conduction velocity in the LA (P = 0.009) and RA (P < 0.0001); greater number (P < 0.0001) and duration (P< 0.0001) of bipoles along the CT with delayed conduction; lower atrial voltage in the LA (P < 0.0001) and RA (P < 0.0001); and more frequent electrical scar (P = 0.001) compared with controls. Five of twelve with MS and none of the controls developed AF with extra-stimulus (P = 0.02). Atrial remodelling in MS is characterized by LA enlargement, loss of myocardium, and scarring associated with widespread and site-specific conduction abnormalities and no change or an increase in ERP. These abnormalities were associated with a heightened inducibility of AF.
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Refractory lining system for high wear area of high temperature reaction vessel
Hubble, David H.; Ulrich, Klaus H.
1998-01-01
A refractory-lined high temperature reaction vessel comprises a refractory ring lining constructed of refractory brick, a cooler, and a heat transfer medium disposed between the refractory ring lining and the cooler. The refractory brick comprises magnesia (MgO) and graphite. The heat transfer medium contacts the refractory brick and a cooling surface of the cooler, and is composed of a material that accommodates relative movement between the refractory brick and the cooler. The brick is manufactured such that the graphite has an orientation providing a high thermal conductivity in the lengthwise direction through the brick that is higher than the thermal conductivity in directions perpendicular to the lengthwise direction. The graphite preferably is flake graphite, in the range of about 10 to 20 wt %, and has a size distribution selected to provide maximum brick density. The reaction vessel may be used for performing a reaction process including the steps of forming a layer of slag on a melt in the vessel, the slag having a softening point temperature range, and forming a protective frozen layer of slag on the interior-facing surface of the refractory lining in at least a portion of a zone where the surface contacts the layer of slag, the protective frozen layer being maintained at or about the softening point of the slag.
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Heckert, Jason; Sankineni, Abhinav; Hughes, William B; Harbison, Sean; Parkman, Henry
2016-01-01
Gastric electric stimulation (GES) is used to treat patients with refractory gastroparesis symptoms. However, the effectiveness of GES in clinical practice and the effect of GES on specific symptoms of gastroparesis are not well delineated. To determine the effectiveness of GES for treatment for refractory symptoms of gastroparesis, the improvement in specific symptoms of gastroparesis, and clinical factors impacting on outcome. Enterra GES was used to treat refractory gastroparesis symptoms. Patients filled out a symptom severity questionnaire (PAGI-SYM) prior to insertion. At each follow-up visit, the patient filled out PAGI-SYM and assessed their therapeutic response using the Clinical Patient Grading Assessment Scale (CPGAS). One hundred and fifty-one patients (120 females) with refractory gastroparesis (72 diabetic, 73 idiopathic, 6 other) underwent GES. Of the 138 with follow-up (1.4 ± 1.0 years), the average CPGAS was 2.4 ± 0.3 (SEM): 104 patients (75 %) improved (CPGAS > 0) and 34 (25 %) did not (CPGAS ≤ 0). Sixty patients (43 %) were at least moderately improved (CPGAS score ≥4). Clinical improvement was seen in both diabetic and idiopathic patients with the CPGAS in diabetic patients (3.5 ± 0.3) higher in idiopathic patients (1.5 ± 0.5; p < 0.05). Symptoms significantly improving the most included nausea, loss of appetite, and early satiety. Vomiting improved in both diabetic and idiopathic patients although the diabetic subgroup experienced a significantly greater reduction in vomiting than the idiopathic subgroup. In this cohort of patients with refractory gastroparesis, GES improved symptoms in 75 % of patients with 43 % being at least moderately improved. Response in diabetics was better than in nondiabetic patients. Nausea, loss of appetite, and early satiety responded the best.
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Timing Actions to Avoid Refractoriness: A Simple Solution for Streaming Sensory Signals
Nogueira, Javier; Caputi, Ángel Ariel
2011-01-01
Segmenting self- from allo-generated signals is crucial for active sensory processing. We report a dynamic filter used by South American pulse electric fish to distinguish active electro-sensory signals carried by their own electric discharges from other concomitant electrical stimuli (i.e. communication signals). The filter has a sensory component, consisting of an onset type central electro-sensory neuron, and a motor component, consisting of a change in the fish's discharge rate when allo-generated electrical events occur in temporal proximity to the fish's own discharge. We investigated the sensory component of the filter by in vitro mimicking synaptic inputs occurring during behavioral responses to allo-generated interfering signals. We found that active control of the discharge enhances self-generated over allo-generated responses by forcing allo-generated signals into a central refractory period. This hypothesis was confirmed by field potential recordings in freely discharging fish. Similar sensory-motor mechanisms may also contribute to signal segmentation in other sensory systems. PMID:21789228
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NASA Astrophysics Data System (ADS)
Huang, C.; Yamabe-Mitarai, Y.; Harada, H.
2002-02-01
Five prealloyed powder samples prepared from binary Ir-based refractory superalloys were sintered at 1800 °C for 4 h by Pulse Electric Current Sintering (PECS). No metal loss was observed during sintering. The relative densities of the sintered specimens all exceeded 90% T.D. The best one was Ir-13% Hf with the density of 97.82% T.D. Phases detected in sintered samples were in accordance with the phase diagram as expected. Fractured surfaces were observed in two samples (Ir-13% Hf and Ir-15% Zr). Some improvements obtained by using prealloyed powders instead of elemental powders, which were investigated in the previous studies, were presented.
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Refractory lining system for high wear area of high temperature reaction vessel
Hubble, D.H.; Ulrich, K.H.
1998-04-21
A refractory-lined high temperature reaction vessel comprises a refractory ring lining constructed of refractory brick, a cooler, and a heat transfer medium disposed between the refractory ring lining and the cooler. The refractory brick comprises magnesia (MgO) and graphite. The heat transfer medium contacts the refractory brick and a cooling surface of the cooler, and is composed of a material that accommodates relative movement between the refractory brick and the cooler. The brick is manufactured such that the graphite has an orientation providing a high thermal conductivity in the lengthwise direction through the brick that is higher than the thermal conductivity in directions perpendicular to the lengthwise direction. The graphite preferably is flake graphite, in the range of about 10 to 20 wt %, and has a size distribution selected to provide maximum brick density. The reaction vessel may be used for performing a reaction process including the steps of forming a layer of slag on a melt in the vessel, the slag having a softening point temperature range, and forming a protective frozen layer of slag on the interior-facing surface of the refractory lining in at least a portion of a zone where the surface contacts the layer of slag, the protective frozen layer being maintained at or about the softening point of the slag. 10 figs.
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Refractory lining system for high wear area of high temperature reaction vessel
Hubble, D.H.; Ulrich, K.H.
1998-09-22
A refractory-lined high temperature reaction vessel comprises a refractory ring lining constructed of refractory brick, a cooler, and a heat transfer medium disposed between the refractory ring lining and the cooler. The refractory brick comprises magnesia (MgO) and graphite. The heat transfer medium contacts the refractory brick and a cooling surface of the cooler, and is composed of a material that accommodates relative movement between the refractory brick and the cooler. The brick is manufactured such that the graphite has an orientation providing a high thermal conductivity in the lengthwise direction through the brick that is higher than the thermal conductivity in directions perpendicular to the lengthwise direction. The graphite preferably is flake graphite, in the range of about 10 to 20 wt %, and has a size distribution selected to provide maximum brick density. The reaction vessel may be used for performing a reaction process including the steps of forming a layer of slag on a melt in the vessel, the slag having a softening point temperature range, and forming a protective frozen layer of slag on the interior-facing surface of the refractory lining in at least a portion of a zone where the surface contacts the layer of slag, the protective frozen layer being maintained at or about the softening point of the slag. 10 figs.
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Hino, H; Oda, Y; Yoshida, Y; Suzuki, T; Shimada, M; Nishikawa, K
2018-02-01
We hypothesized that, compared with propofol, desflurane prolongs the antegrade accessory pathway effective refractory period (APERP) in children undergoing radiofrequency catheter ablation for Wolff-Parkinson-White (WPW) syndrome. In this randomized crossover study, children aged 4.1-16.1 years undergoing radiofrequency catheter ablation for WPW syndrome were randomly divided into four groups according to the concentration of desflurane and anesthetics used in the first and the second electrophysiological studies (EPS). After induction of general anesthesia with propofol and tracheal intubation, they received one of the following regimens: 0.5 minimum alveolar concentration (MAC) desflurane (first EPS) and propofol (second EPS) (Des0.5-Prop group, n = 8); propofol (first EPS) and 0.5 MAC desflurane (second EPS) (Prop-Des0.5 group, n = 9); 1 MAC desflurane (first EPS) and propofol (second EPS) (Des1.0-Prop group, n = 10); propofol (first EPS) and 1 MAC desflurane (second EPS) (Prop-Des1.0 group, n = 9). Radiofrequency catheter ablation was performed upon completion of EPS. Sample size was determined to detect a difference in the APERP. Desflurane at 1.0 MAC significantly prolonged the APERP compared with propofol, but did not affect the sinoatrial conduction time, atrio-His interval or atrioventricular node effective refractory period. Supraventricular tachycardia was induced in all children receiving propofol, but not induced in 1 and 4 children receiving 0.5 MAC and 1.0 MAC desflurane, respectively. Desflurane enhances the refractoriness and may block the electrical conduction of the atrioventricular accessory pathway, and is therefore not suitable for use in children undergoing radiofrequency catheter ablation for WPW syndrome. © 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.
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Kulboka, Arūnas; Veikutis, Vincentas; Pauza, Dainius Haroldas; Lekas, Raimundas
2003-01-01
The aims of present study were to verify the topography of the intracardiac nerve subplexuses (INS) by using electrophysiological methods, its relations with sinoatrial (SA) node function and to investigate possibility of selective surgical SA node denervation. Fifteen mongrel dogs of either sex weighing 8 to 15 kg were used for electrophysiological studies. Both cervical vagosympathetic trunks were isolated and crushed by tight ligatures. Nervus subplexuses destructions were performed by cryocoagulation in three zones located around the right superior vena cava: ventral, lateral and dorsal. The sinus rhythm, SA node function recovery time, AV node conductivity, AV node and atrial effective refractory period were measured. Five experiments in each of three zones were performed. Experimental data show that destruction of the epicardial nerves has different effect on electrophysiological parameters. After destruction of the anterior zone of the right atrium the sinus rhythm decreased on an average by 11.6%; SA node function recovery time prolonged by 7.2%; AV node conductivity decreased by 13.1%; AV node effective refractory period prolonged by 12.9% and atrial effective refractory period, by 10.9 %. Measurements of electrophysiological parameters after intravenous injection of atropine sulphate show that sinus rhythm decreased on an average by 23.4%; SA node function recovery time increased by 9.1%; the conductivity of AV node decreased by 10.2%; AV node effective refractory period prolonged by 15.4% and atrial effective refractory period, by 13.2%. After destruction of the intracardiac nerves of the lateral zone, the sinus rhythm decreased by 15.7%; SA node function recovery time increased by 16.3%; AV node conductivity decreased by 8.3%; AV node effective refractory period and atrial effective refractory period prolonged by 11.9% and 10.0%, respectively. After the atropine sulphate intravenous injection, the sinus rhythm decreased on an average by 7.1%, SA node function recovery time prolonged by 7.1%, AV conductivity decreased by 9.1%, AV node effective refractory period increased by 12.4%, and atrial effective refractory period prolonged by 12.5%. After destruction of the nerves in the dorsal zone the changes of electrophysiological parameters were opposite to those obtained after destruction of the nerve tracts in the anterior or lateral zones: the sinus rhythm increased on an average by 4.3%; SA node function recovery time shortened by 8.8%; AV conductivity increased by 9.7%; AV node and atrial effective refractory period decreased by 12.3% and 12.1%, respectively. After intravenous atropine sulphate infusion, sinus rhythm decreased on an average by 8.3%; SA node function recovery time prolonged by 9.6%; AV node conductivity decreased by 5%; AV node and atrial effective refractory period prolonged by 4.2% and 5.2%, respectively. The average changes of electrophysiological parameters before and after INS destruction shows that cryocoagulation of ventral and lateral zones eliminates the effects of sympathetic tone to SA and AV nodal activity. Cryocoagulation of dorsal zone eliminates the effects of nervus vagus to both nodal structures. These findings shows the possibility alter or correct SA node function by making selective surgical SA node denervation.
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Restitution slope is principally determined by steady-state action potential duration.
Shattock, Michael J; Park, Kyung Chan; Yang, Hsiang-Yu; Lee, Angela W C; Niederer, Steven; MacLeod, Kenneth T; Winter, James
2017-06-01
The steepness of the action potential duration (APD) restitution curve and local tissue refractoriness are both thought to play important roles in arrhythmogenesis. Despite this, there has been little recognition of the apparent association between steady-state APD and the slope of the restitution curve. The objective of this study was to test the hypothesis that restitution slope is determined by APD and to examine the relationship between restitution slope, refractoriness and susceptibility to VF. Experiments were conducted in isolated hearts and ventricular myocytes from adult guinea pigs and rabbits. Restitution curves were measured under control conditions and following intervention to prolong (clofilium, veratridine, bretylium, low [Ca]e, chronic transverse aortic constriction) or shorten (catecholamines, rapid pacing) ventricular APD. Despite markedly differing mechanisms of action, all interventions that prolonged the action potential led to a steepening of the restitution curve (and vice versa). Normalizing the restitution curve as a % of steady-state APD abolished the difference in restitution curves with all interventions. Effects on restitution were preserved when APD was modulated by current injection in myocytes pre-treated with the calcium chelator BAPTA-AM - to abolish the intracellular calcium transient. The non-linear relation between APD and the rate of repolarization of the action potential is shown to underpin the common influence of APD on the slope of the restitution curve. Susceptibility to VF was found to parallel changes in APD/refractoriness, rather than restitution slope. Steady-state APD is the principal determinant of the slope of the ventricular electrical restitution curve. In the absence of post-repolarization refractoriness, factors that prolong the action potential would be expected to steepen the restitution curve. However, concomitant changes in tissue refractoriness act to reduce susceptibility to sustained VF. Dependence on steady-state APD may contribute to the failure of restitution slope to predict sudden cardiac death. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Cardiology
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Restitution slope is principally determined by steady-state action potential duration
Shattock, Michael J.; Park, Kyung Chan; Yang, Hsiang-Yu; Lee, Angela W. C.; Niederer, Steven; MacLeod, Kenneth T.
2017-01-01
Aims The steepness of the action potential duration (APD) restitution curve and local tissue refractoriness are both thought to play important roles in arrhythmogenesis. Despite this, there has been little recognition of the apparent association between steady-state APD and the slope of the restitution curve. The objective of this study was to test the hypothesis that restitution slope is determined by APD and to examine the relationship between restitution slope, refractoriness and susceptibility to VF. Methods and results Experiments were conducted in isolated hearts and ventricular myocytes from adult guinea pigs and rabbits. Restitution curves were measured under control conditions and following intervention to prolong (clofilium, veratridine, bretylium, low [Ca]e, chronic transverse aortic constriction) or shorten (catecholamines, rapid pacing) ventricular APD. Despite markedly differing mechanisms of action, all interventions that prolonged the action potential led to a steepening of the restitution curve (and vice versa). Normalizing the restitution curve as a % of steady-state APD abolished the difference in restitution curves with all interventions. Effects on restitution were preserved when APD was modulated by current injection in myocytes pre-treated with the calcium chelator BAPTA-AM – to abolish the intracellular calcium transient. The non-linear relation between APD and the rate of repolarization of the action potential is shown to underpin the common influence of APD on the slope of the restitution curve. Susceptibility to VF was found to parallel changes in APD/refractoriness, rather than restitution slope. Conclusion(s) Steady-state APD is the principal determinant of the slope of the ventricular electrical restitution curve. In the absence of post-repolarization refractoriness, factors that prolong the action potential would be expected to steepen the restitution curve. However, concomitant changes in tissue refractoriness act to reduce susceptibility to sustained VF. Dependence on steady-state APD may contribute to the failure of restitution slope to predict sudden cardiac death. PMID:28371805
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A design study of hydrazine and biowaste resistojets
NASA Technical Reports Server (NTRS)
Page, R. J.; Stoner, W. A.; Barker, L.
1986-01-01
A generalized modeling program was adapted in BASIC on a personal computer to compare the performance of four types of biowaste resistojets and two types of hydrazine augmenters. Analyzed biowaste design types were: (1) an electrically conductive ceramic heater-exchanger of zirconia; (2) a truss heater of platinum in cross flow; (3) an immersed bicoiled tubular heater-exchanger; and (4) a nonexposed, refractory metal, radiant heater in a central cavity within a heat exchanger case. Concepts 2 and 3 are designed to have an efficient, stainless steel outer pressure case. The hydrazine design types are: (5) an immersed bicoil heater exchanger and (6) a nonexposed radiant heater now with a refractory metal case. The ceramic biowaste resistojet has the highest specific impulse growth potential at 2000 K of 192.5 (CO2) and 269 s (H2O). The bicoil produces the highest augmenter temperature of 1994 K for a 2073 K heater giving 317 s at .73 overall efficiency. Detailed temperature profiles of each of the designs are shown. The scaled layout drawings of each are presented with recommended materials and fabrication methods.
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Tokunaga, Chiho; Tsukada, Toru; Sakamoto, Hiroaki; Naruse, Yoshihisa; Yoshida, Kentaro; Sekiguchi, Yukio; Imai, Akito; Aonuma, Kazutaka; Hiramatsu, Yuji
2016-01-01
Electrical storm is a rare but critical complication following revascularization in patients with ischemic heart disease. We report the case of a 67-year-old man who developed drug refractory intractable electrical storm after emergent coronary artery bypass grafting for ischemic cardiomyopathy. The electrical storm was successfully eliminated by percutaneous endocardial radiofrequency catheter ablation targeting the abnormal Purkinje-related triggering ventricular premature contractions in a low-voltage zone. © 2015 Wiley Periodicals, Inc.
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NASA Technical Reports Server (NTRS)
Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Coffman, Brekke E.; Sampson, Jeffrey W.; Kolody, Mark R.; Curran, Jerome P.; Perusich, Stephen A.; Trejo, David; Whitten, Mary C.;
2009-01-01
A trade study and litera ture survey of refractory materials (fi rebrick. refractory concrete. and si licone and epoxy ablatives) were conducted to identify candidate replacement materials for Launch Complexes 39A and 398 at Kennedy Space Center (KSC). In addition, site vis its and in terviews with industry expens and vendors of refractory materials were conducted. As a result of the si te visits and interviews, several products were identified for launch applications. Firebrick is costly to procure and install and was not used in the si tes studied. Refractory concrete is gunnable. adheres well. and costs less 10 install. Martyte. a ceramic fi lled epoxy. can protect structural stccl but is costly. difficullto apply. and incompatible with silicone ablatives. Havanex, a phenolic ablative material, is easy to apply but is costly and requires frequent replacement. Silicone ablatives are ineJ[pensive, easy to apply. and perl'onn well outside of direct rocket impingement areas. but refractory concrete and epoxy ablatives provide better protection against direcl rocket exhaust. None of the prodUCIS in this trade study can be considered a panacea for these KSC launch complexes. but the refractory products. individually or in combination, may be considered for use provided the appropriate testing requirements and specifications are met.
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The effect of various sintering temperature on used refractory towards its physical properties
NASA Astrophysics Data System (ADS)
Sudibyo; Wulandari, Y. R.; Amin, M.; Azhar
2018-01-01
The used magnesia refractory from the kiln of cement industry was successfully recycled to new refractory using Kaolin as an adhesive. In this work, the temperatures of sintering were varied from 1000°C to 1500°C. The result shows that the increment temperature effects in sintering process will enhance refractory physical properties such as bulk density, cold crushing strength or pressure strength and thermal conductivity. Meanwhile, the porosity was decreased as the increase of the sintering temperature.
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Holmes, Jeffrey W; Laksman, Zachary; Gepstein, Lior
2016-01-01
Following myocardial infarction (MI), damaged myocytes are replaced by collagenous scar tissue, which serves an important mechanical function - maintaining integrity of the heart wall against enormous mechanical forces - but also disrupts electrical function as structural and electrical remodeling in the infarct and borderzone predispose to re-entry and ventricular tachycardia. Novel emerging regenerative approaches aim to replace this scar tissue with viable myocytes. Yet an alternative strategy of therapeutically modifying selected scar properties may also prove important, and in some cases may offer similar benefits with lower risk or regulatory complexity. Here, we review potential goals for such modifications as well as recent proof-of-concept studies employing specific modifications, including gene therapy to locally increase conduction velocity or prolong the refractory period in and around the infarct scar, and modification of scar anisotropy to improve regional mechanics and pump function. Another advantage of scar modification techniques is that they have applications well beyond MI. In particular, ablation treats electrical abnormalities of the heart by intentionally generating scar to block aberrant conduction pathways. Yet in diseases such as atrial fibrillation (AF) where ablation can be extensive, treating the electrical disorder can significantly impair mechanical function. Creating smaller, denser scars that more effectively block conduction, and choosing the location of those lesions by balancing their electrical and mechanical impacts, could significantly improve outcomes for AF patients. We review some recent advances in this area, including the use of computational models to predict the mechanical effects of specific lesion sets and gene therapy for functional ablation. Overall, emerging techniques for modifying scar properties represents a potentially important set of tools for improving patient outcomes across a range of heart diseases, whether used in place of or as an adjunct to regenerative approaches. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Kashimura, Takeshi; Kodama, Makoto; Watanabe, Tohru; Tanaka, Komei; Hayashi, Yuka; Ohno, Yukako; Obata, Hiroaki; Ito, Masahiro; Hirono, Satoru; Hanawa, Haruo; Minamino, Tohru
2014-02-01
Mechanical alternans (MA) and electrical alternans (EA) are predictors of cardiac events. Experimental studies have suggested that refractoriness of calcium cycling underlies these cardiac alternans. However, refractoriness of left ventricular contraction has not been examined in patients with cardiac alternans. In 51 patients with miscellaneous heart diseases, incremental right atrial pacing was performed to induce MA and EA. MA was quantified by alternans amplitude (AA: the difference between left ventricular dP/dt of a strong beat and that of a weak beat), and AA at 100/min (AA100) and maximal AA (AAmax) were measured. EA was defined as alternation of T wave morphology in 12-lead electrocardiogram. Relative refractoriness of left ventricular contraction was examined by drawing the mechanical restitution curve under a basal coupling interval (BCL) of 600 ms (100/min) and was assessed by the slope at BCL (Δmechanical restitution). Postextrasystolic potentiation (PESP) was also examined and the slope of PESP curve (ΔPESP) was assessed as a property to alternate strong and weak beats. MA and EA were induced in 19 patients and in none at 100/min or less, and at any heart rate in 32 and in 10, respectively. AA100 and AAmax correlated positively with Δmechanical restitution and negatively with ΔPESP. Patients with EA had a significantly larger Δmechanical restitution and a significantly larger absolute value of ΔPESP than those without. In patients with MA and EA, the left ventricular contractile force during tachycardia is under relative refractoriness and prone to cause large fluctuation of contractile force. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.
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Composition and process for making an insulating refractory material
Pearson, A.; Swansiger, T.G.
1998-04-28
A composition and process are disclosed for making an insulating refractory material. The composition includes calcined alumina powder, flash activated alumina powder, an organic polymeric binder and a liquid vehicle which is preferably water. Starch or modified starch may also be added. A preferred insulating refractory material made with the composition has a density of about 2.4--2.6 g/cm{sup 3} with reduced thermal conductivity, compared with tabular alumina. Of importance, the formulation has good abrasion resistance and crush strength during intermediate processing (commercial sintering) to attain full strength and refractoriness.
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Moreno, Lucas; Rubie, Herve; Varo, Amalia; Le Deley, Marie Cecile; Amoroso, Loredana; Chevance, Aurelie; Garaventa, Alberto; Gambart, Marion; Bautista, Francisco; Valteau-Couanet, Dominique; Geoerger, Birgit; Vassal, Gilles; Paoletti, Xavier; Pearson, Andrew D J
2017-01-01
Few randomized trials have been conducted in children with relapsed/refractory neuroblastoma and data about outcomes including progression-free survival (PFS) in these patients are scarce. A meta-analysis of three phase II studies of children with relapsed/refractory neuroblastoma conducted in Europe (temozolomide, topotecan-vincristine-doxorubicin and topotecan-temozolomide) was performed. Individual patient data with extended follow-up were collected from the trial databases after publication to describe trial outcomes (response rate, clinical benefit ratio, duration of treatment, PFS, and overall survival [OS]). Characteristics of subjects with relapsed/refractory neuroblastoma were compared. Data from 71 children and adolescents with relapsed/refractory neuroblastoma were collected. Response definitions were not homogeneous in the three trials. Patients were on study for a median of 3.5 months (interquartile range [IQR] 1.9-6.2). Of those, 35.2% achieved a complete or partial response, 26.3% experienced a response after more than two cycles, and 23.9% received more than six cycles. Median PFS from study entry for all, refractory, and relapsed patients was 6.4 ± 1.0, 12.5 ± 6.8, and 5.7 ± 1.0 months, respectively (P = 0.006). Median OS from study entry for all, refractory, and relapsed patients was 16.1 ± 4.3, 27.9 ± 20.2, and 11.0 ± 1.6 months, respectively (P = 0.03). Baseline data for response rate, clinical benefit ratio, duration of treatment, PFS, and OS were provided. Two subpopulations (relapsed/refractory) were clearly distinct and should be included in the interpretation of all trials. These results should help informing the design of forthcoming studies in relapsed/refractory neuroblastoma. © 2016 Wiley Periodicals, Inc.
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Scarponi, Letizia; Mozzanica, Francesco; De Cristofaro, Valeria; Ginocchio, Daniela; Pizzorni, Nicole; Bottero, Alessandro; Schindler, Antonio
2015-01-01
The aim of this study was to evaluate the role of neuromuscular electrical stimulation (NMES) in tube-fed patients with severe and chronic dysphagia refractory to traditional swallowing therapy (TT). A total of 11 consecutive dysphagic patients with tube-dependent nutrition and who had not responded to 6 months of TT were enrolled. Each patient received NMES for 30 min and TT for 30 min, twice a day, 5 days per week for 4 weeks. In order to evaluate the swallowing impairment, each patient underwent a fiberoptic endoscopic examination of swallowing immediately before the beginning of the treatment, after 2 weeks and after 4 weeks. All enrolled patients managed to complete the swallowing treatment protocol for at least 2 weeks. After the 4-week treatment, 6 of 11 enrolled patients passed to a total oral diet with single or multiple consistencies despite specific food limitations or special preparation or compensation. Five patients, all affected by the most severe form of dysphagia, maintained tube-dependent nutrition. NMES as adjunctive treatment to TT may offer a new possibility for the management of tube-fed patients who are refractory to TT. © 2016 S. Karger AG, Basel.
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Development of high strength ferritic steel for interconnect application in SOFCs
NASA Astrophysics Data System (ADS)
Froitzheim, J.; Meier, G. H.; Niewolak, L.; Ennis, P. J.; Hattendorf, H.; Singheiser, L.; Quadakkers, W. J.
High-Cr ferritic model steels containing various additions of the refractory elements Nb and/or W were studied with respect to oxidation behaviour (hot) tensile properties, creep behaviour and high-temperature electrical conductivity of the surface oxide scales. Whereas W additions of around 2 wt.% had hardly any effect on the oxidation rates at 800 and 900 °C, Nb additions of 1% led to a substantially enhanced growth rate of the protective surface oxide scale. It was found that this adverse effect can be alleviated by suitable Si additions. This is related to the incorporation of Si and Nb into Laves phase precipitates which also contribute to increased creep and hot tensile strength. The dispersion of Laves phase precipitates was greatly refined by combined additions of Nb and W. The high-temperature electrical conductivity of the surface oxide scales was similar to that of the Nb/W-free alloys. Thus the combined additions of Nb, W and Si resulted in an alloy with oxidation resistance, ASR contribution and thermal expansion comparable to the commercial alloy Crofer 22 APU, but with creep strength far greater than that of Crofer 22 APU.
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Zhang, Xueqin; Feng, Huajun; Liang, Yuxiang; Zhao, Zhiqing; Long, Yuyang; Fang, Yuan; Wang, Meizhen; Yin, Jun; Shen, Dongsheng
2015-05-01
Low temperature aggravates biological treatment of refractory p-fluoronitrobenzene (p-FNB) because of microtherm inhibition of microbial activity. Considering the potential characterization of energy supply for microbial metabolism and spurring microbial activity by electrical stimulation, a bioelectrochemical system (BES) was established to provide sustaining electrical stimulation for p-FNB mineralization at a low temperature. Electrical stimulation facilitated p-FNB treatment and bioelectrochemical reaction rate constants for the removal and defluorination of p-FNB at 10 °C were 0.0931 and 0.0054 h(-1), which were higher than the sums of the rates found using a biological system and an electrocatalytic system by 62.8 and 64.8%, respectively. At a low temperature, microbial activity in terms of dehydrogenase and ATPase was found to be higher with electrical stimulation, being 121.1 and 100.1% more active than that in the biological system. Moreover, stronger antioxidant ability was observed in the BES, which implied a better cold-resistance and relief of microtherm inhibition by electrical stimulation. Bacterial diversity analysis revealed a significant evolution of microbial community by electrical stimulation, and Clostridia was uniquely enriched. One bacterial sequence close to Pseudomonas became uniquely predominant, which appeared to be crucial for excellent p-FNB treatment performance in the BES at a low temperature. Economic evaluation revealed that the energy required to mineralize an extra mole of p-FNB was found to be 247 times higher by heating the system than by application of electrical stimulation. These results indicated that application of electrical stimulation is extremely promising for treating refractory waste at low temperatures.
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Acidosis slows electrical conduction through the atrio-ventricular node
Nisbet, Ashley M.; Burton, Francis L.; Walker, Nicola L.; Craig, Margaret A.; Cheng, Hongwei; Hancox, Jules C.; Orchard, Clive H.; Smith, Godfrey L.
2014-01-01
Acidosis affects the mechanical and electrical activity of mammalian hearts but comparatively little is known about its effects on the function of the atrio-ventricular node (AVN). In this study, the electrical activity of the epicardial surface of the left ventricle of isolated Langendorff-perfused rabbit hearts was examined using optical methods. Perfusion with hypercapnic Tyrode's solution (20% CO2, pH 6.7) increased the time of earliest activation (Tact) from 100.5 ± 7.9 to 166.1 ± 7.2 ms (n = 8) at a pacing cycle length (PCL) of 300 ms (37°C). Tact increased at shorter PCL, and the hypercapnic solution prolonged Tact further: at 150 ms PCL, Tact was prolonged from 131.0 ± 5.2 to 174.9 ± 16.3 ms. 2:1 AVN block was common at shorter cycle lengths. Atrial and ventricular conduction times were not significantly affected by the hypercapnic solution suggesting that the increased delay originated in the AVN. Isolated right atrial preparations were superfused with Tyrode's solutions at pH 7.4 (control), 6.8 and 6.3. Low pH prolonged the atrial-Hisian (AH) interval, the AVN effective and functional refractory periods and Wenckebach cycle length significantly. Complete AVN block occurred in 6 out of 9 preparations. Optical imaging of conduction at the AV junction revealed increased conduction delay in the region of the AVN, with less marked effects in atrial and ventricular tissue. Thus acidosis can dramatically prolong the AVN delay, and in combination with short cycle lengths, this can cause partial or complete AVN block and is therefore implicated in the development of brady-arrhythmias in conditions of local or systemic acidosis. PMID:25009505
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Acidosis slows electrical conduction through the atrio-ventricular node.
Nisbet, Ashley M; Burton, Francis L; Walker, Nicola L; Craig, Margaret A; Cheng, Hongwei; Hancox, Jules C; Orchard, Clive H; Smith, Godfrey L
2014-01-01
Acidosis affects the mechanical and electrical activity of mammalian hearts but comparatively little is known about its effects on the function of the atrio-ventricular node (AVN). In this study, the electrical activity of the epicardial surface of the left ventricle of isolated Langendorff-perfused rabbit hearts was examined using optical methods. Perfusion with hypercapnic Tyrode's solution (20% CO2, pH 6.7) increased the time of earliest activation (Tact) from 100.5 ± 7.9 to 166.1 ± 7.2 ms (n = 8) at a pacing cycle length (PCL) of 300 ms (37°C). Tact increased at shorter PCL, and the hypercapnic solution prolonged Tact further: at 150 ms PCL, Tact was prolonged from 131.0 ± 5.2 to 174.9 ± 16.3 ms. 2:1 AVN block was common at shorter cycle lengths. Atrial and ventricular conduction times were not significantly affected by the hypercapnic solution suggesting that the increased delay originated in the AVN. Isolated right atrial preparations were superfused with Tyrode's solutions at pH 7.4 (control), 6.8 and 6.3. Low pH prolonged the atrial-Hisian (AH) interval, the AVN effective and functional refractory periods and Wenckebach cycle length significantly. Complete AVN block occurred in 6 out of 9 preparations. Optical imaging of conduction at the AV junction revealed increased conduction delay in the region of the AVN, with less marked effects in atrial and ventricular tissue. Thus acidosis can dramatically prolong the AVN delay, and in combination with short cycle lengths, this can cause partial or complete AVN block and is therefore implicated in the development of brady-arrhythmias in conditions of local or systemic acidosis.
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NASA Astrophysics Data System (ADS)
Carroll, B.; Kharkovsky, S.; Zoughi, R.; Limmer, R.
2009-03-01
A frequency-modulated continuous-wave (FM-CW) handheld radar operating in the frequency range of 8-18 GHz, resulting in a relatively fine range resolution was designed and constructed for on-site inspection of refractory structure thickness. This paper presents the design of the radar and the results of measurements conducted on typical refractory furnace structures assembled in the laboratory.
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Carbon Nanofibers Synthesized on Selective Substrates for Nonvolatile Memory and 3D Electronics
NASA Technical Reports Server (NTRS)
Kaul, Anupama B.; Khan, Abdur R.
2011-01-01
A plasma-enhanced chemical vapor deposition (PECVD) growth technique has been developed where the choice of starting substrate was found to influence the electrical characteristics of the resulting carbon nanofiber (CNF) tubes. It has been determined that, if the tubes are grown on refractory metallic nitride substrates, then the resulting tubes formed with dc PECVD are also electrically conducting. Individual CNFs were formed by first patterning Ni catalyst islands using ebeam evaporation and liftoff. The CNFs were then synthesized using dc PECVD with C2H2:NH3 = [1:4] at 5 Torr and 700 C, and approximately equal to 200-W plasma power. Tubes were grown directly on degenerately doped silicon <100> substrates with resistivity rho approximately equal to 1-5 meterohm-centimeter, as well as NbTiN. The approximately equal to 200-nanometer thick refractory NbTiN deposited using magnetron sputtering had rho approximately equal to 113 microohm-centimeter and was also chemically compatible with CNF synthesis. The sample was then mounted on a 45 beveled Al holder, and placed inside a SEM (scanning electron microscope). A nanomanipulator probe stage was placed inside the SEM equipped with an electrical feed-through, where tungsten probes were used to make two-terminal electrical measurements with an HP 4156C parameter analyzer. The positive terminal nanoprobe was mechanically manipulated to physically contact an individual CNF grown directly on NbTiN as shown by the SEM image in the inset of figure (a), while the negative terminal was grounded to the substrate. This revealed the tube was electrically conductive, although measureable currents could not be detected until approximately equal to 6 V, after which point current increased sharply until compliance (approximately equal to 50 nA) was reached at approximately equal to 9.5 V. A native oxide on the tungsten probe tips may contribute to a tunnel barrier, which could be the reason for the suppressed transport at low biases. Currents up to approximately 100 nA could be cycled, which are likely to propagate via the tube surface, or sidewalls, rather than the body, which is shown by the I-V in figure (a). Electrical conduction via the sidewalls is a necessity for dc NEMS (nanoelectromechanical system) applications, more so than for the field emission applications of such tubes. During the tests, high conductivity was expected, because both probes were shorted to the substrate, as shown by curve 1 in the I-V characteristic in figure (b). When a tube grown on NbTiN was probed, the response was similar to the approximately equal to 100 nA and is represented by curve 2 in figure (b), which could be cycled and propagated via the tube surface or the sidewalls. However, no measureable currents for the tube grown directly on Si were observed as shown by curve 3 in figure (b), even after testing over a range of samples. This could arise from a dielectric coating on the sidewalls for tubes on Si. As a result of the directional nature of ion bombardment during dc PECVD, Si from the substrate is likely re-sputtered and possibly coats the sidewalls.
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Electrophysiological determinants of hypokalaemia-induced arrhythmogenicity in the guinea-pig heart.
Osadchii, O E; Olesen, S P
2009-12-01
Hypokalaemia is an independent risk factor contributing to arrhythmic death in cardiac patients. In the present study, we explored the mechanisms of hypokalaemia-induced tachyarrhythmias by measuring ventricular refractoriness, spatial repolarization gradients, and ventricular conduction time in isolated, perfused guinea-pig heart preparations. Epicardial and endocardial monophasic action potentials from distinct left ventricular (LV) and right ventricular (RV) recording sites were monitored simultaneously with volume-conducted electrocardiogram (ECG) during steady-state pacing and following a premature extrastimulus application at progressively reducing coupling stimulation intervals in normokalaemic and hypokalaemic conditions. Hypokalaemic perfusion (2.5 mm K(+) for 30 min) markedly increased the inducibility of tachyarrhythmias by programmed ventricular stimulation and rapid pacing, prolonged ventricular repolarization and shortened LV epicardial and endocardial effective refractory periods, thereby increasing the critical interval for LV re-excitation. Hypokalaemia increased the RV-to-LV transepicardial repolarization gradients but had no effect on transmural dispersion of APD(90) and refractoriness across the LV wall. As determined by local activation time recordings, the LV-to-RV transepicardial conduction and the LV transmural (epicardial-to-endocardial) conduction were slowed in hypokalaemic heart preparations. This change was attributed to depressed diastolic excitability as evidenced by increased ventricular pacing thresholds. These findings suggest that hypokalaemia-induced arrhythmogenicity is attributed to shortened LV refractoriness, increased critical intervals for LV re-excitation, amplified RV-to-LV transepicardial repolarization gradients and slowed ventricular conduction in the guinea-pig heart.
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Composition and process for making an insulating refractory material
Pearson, Alan; Swansiger, Thomas G.
1998-04-28
A composition and process for making an insulating refractory material. The composition includes calcined alumina powder, flash activated alumina powder, an organic polymeric binder and a liquid vehicle which is preferably water. Starch or modified starch may also be added. A preferred insulating refractory material made with the composition has a density of about 2.4-2.6 g/cm.sup.3 with reduced thermal conductivity, compared with tabular alumina. Of importance, the formulation has good abrasion resistance and crush strength during intermediate processing (commercial sintering) to attain full strength and refractoriness, good abrasion resistance and crush strength.
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Assessment and Management of Treatment-Refractory Obsessive-Compulsive Disorder in Children
Bloch, Michael H.; Storch, Eric A.
2015-01-01
OBJECTIVE To review the assessment and treatment of treatment-refractory pediatric obsessive-compulsive disorder (OCD). METHOD A PubMed search was conducted to identify controlled trials in pediatric OCD. Additionally, practice guidelines for the treatment of adults and children were further reviewed for references in treatment-refractory OCD across the lifespan. RESULTS Pharmacotherapy with selective serotonin reuptake inhibitors (SSRIs) and cognitive-behavioral therapy are effective treatments for pediatric OCD. Evidence suggests that CBT is additionally effective even in pediatric patients with refractory OCD symptoms. Antipsychotic augmentation, raising SSRI dosage, and several glutamate-modulating agents have some evidence of efficacy in adults with treatment-refractory OCD but have not been studied in pediatric populations. CONCLUSION Several pharmacological treatment options exist for children with refractory OCD symptoms. However, little evidence-based data exist to guide treatment for our most challenging pediatric OCD patients. Further research is needed to evaluate the efficacy/side-effect profile of commonly used interventions in treatment-refractory pediatric OCD. PMID:25791142
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Hollow cathodes for arcjet thrusters
NASA Technical Reports Server (NTRS)
Luebben, Craig R.; Wilbur, Paul J.
1987-01-01
In an attempt to prevent exterior spot emission, hollow cathode bodies and orifice plates were constructed from boron nitride which is an electrical insulator, but the orifice plates melted and/or eroded at high interelectrode pressures. The most suitable hollow cathodes tested included a refractory metal orifice plate in a boron nitride body, with the insert insulated electrically from the orifice plate. In addition, the hollow cathode interior was evacuated to assure a low pressure at the insert surface, thus promoting diffuse electron emission. At high interelectrode pressures, the electrons tended to flow through the orifice plate rather than through the orifice, which could result in overheating of the orifice plate. Using a carefully aligned centerline anode, electron flow through the orifice could be sustained at interelectrode pressures up to 500 torr - but the current flow path still occasionally jumped from the orifice to the orifice plate. Based on these tests, it appears that a hollow cathode would operate most effectively at pressures in the arcjet regime with a refractory, chemically stable, and electrically insulating cathode body and orifice plate.
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Feasibility and safety of catheter ablation of electrical storm in ischemic dilated cardiomyopathy.
Dello Russo, Antonio; Casella, Michela; Pelargonio, Gemma; Santangeli, Pasquale; Bartoletti, Stefano; Bencardino, Gianluigi; Al-Mohani, Ghaliah; Innocenti, Ester; Di Biase, Luigi; Avella, Andrea; Pappalardo, Augusto; Carbucicchio, Corrado; Bellocci, Fulvio; Fiorentini, Cesare; Natale, Andrea; Tondo, Claudio
2016-06-01
Electrical storm is an emergency in 'implantation of a cardioverter defibrillator' carriers with ischemic dilated cardiomyopathy (DCM) and negatively impacts long-term prognosis. We evaluated the feasibility, safety, and effectiveness of radiofrequency catheter ablation (RFCA) in controlling electrical storm and its impact on survival and ventricular tachycardia/fibrillation recurrence. We enrolled 27 consecutive patients (25 men, age 73.1 ± 6.5 years) with ischemic DCM and an indication to RFCA for drug-refractory electrical storm. The immediate outcome was defined as failure or success, depending on whether the patient's clinical ventricular tachycardia could still be induced after RFCA; electrical storm resolution was defined as no sustained ventricular tachycardia/ventricular fibrillation in the next 7 days. Of the 27 patients, 1 died before RFCA; in the remaining 26 patients, a total of 33 RFCAs were performed. In all 26 patients, RFCA was successful, although in 6/26 patients (23.1%), repeated procedures were needed, including epicardial ablation in 3/26 (11.5%). In 23/26 patients (88.5%), electrical storm resolution was achieved. At a follow-up of 16.7 ± 8.1 months, 5/26 patients (19.2%) had died (3 nonsudden cardiac deaths, 2 noncardiac deaths) and 10/26 patients (38.5%) had ventricular tachycardia recurrence; none had electrical storm recurrence. A worse long-term outcome was associated with lower glomerular filtration rate, wider baseline QRS, and presence of atrial fibrillation before electrical storm onset. In patients with ischemic DCM, RFCA is well tolerated, feasible and effective in the acute management of drug-refractory electrical storm. It is associated with a high rate of absence of sustained ventricular tachycardia episodes over the subsequent 7 days. After successful ablation, long-term outcome was mainly predicted by baseline clinical variables.
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Management of refractory epilepsy.
Muñana, Karen R
2013-05-01
The term refractory epilepsy is utilized in veterinary medicine to describe a condition in which an animal with epilepsy fails to attain satisfactory seizure control or suffers intolerable side effects despite appropriate therapy with conventional antiepileptic drugs. Refractory epilepsy is an important problem in small animal practice as it occurs in approximately one-third of dogs with epilepsy. Consequently, there is much interest in identifying ways to more effectively treat this population of animals. More than a dozen new antiepileptic drugs have been approved for humans over the last 2 decades, and several of these drugs, including gabapentin, zonisamide, levetiracetam, and pregabalin, have been evaluated for the treatment of refractory seizures in veterinary patients. Nonmedical methods to treat poorly controlled epilepsy are also being explored. The 2 alternative forms of therapy that have shown the most promise in humans with epilepsy are electrical stimulation of the brain and dietary modification, both of which have also been evaluated in dogs. This overview summarizes the available data on pharmacologic as well as nonmedical treatment options for dogs and cats with refractory epilepsy. Although many forms of therapy are currently being utilized in clinical practice, our knowledge of the safety and efficacy of these treatments is limited. Additional randomized controlled trials are needed to better evaluate these novel therapies for refractory epilepsy in dogs and cats. © 2013 Elsevier Inc. All rights reserved.
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Refractory metal alloys and composites for space power systems
NASA Technical Reports Server (NTRS)
Stephens, Joseph R.; Petrasek, Donald W.; Titran, Robert H.
1988-01-01
Space power requirements for future NASA and other U.S. missions will range from a few kilowatts to megawatts of electricity. Maximum efficiency is a key goal of any power system in order to minimize weight and size so that the space shuttle may be used a minimum number of times to put the power supply into orbit. Nuclear power has been identified as the primary source to meet these high levels of electrical demand. One way to achieve maximum efficiency is to operate the power supply, energy conversion system, and related components at relatively high temperatures. NASA Lewis Research Center has undertaken a research program on advanced technology of refractory metal alloys and composites that will provide baseline information for space power systems in the 1900's and the 21st century. Basic research on the tensile and creep properties of fibers, matrices, and composites is discussed.
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Frequency dependence of behavioral modulation by hippocampal electrical stimulation
La Corte, Giorgio; Wei, Yina; Chernyy, Nick; Gluckman, Bruce J.
2013-01-01
Electrical stimulation offers the potential to develop novel strategies for the treatment of refractory medial temporal lobe epilepsy. In particular, direct electrical stimulation of the hippocampus presents the opportunity to modulate pathological dynamics at the ictal focus, although the neuroanatomical substrate of this region renders it susceptible to altering cognition and affective processing as a side effect. We investigated the effects of three electrical stimulation paradigms on separate groups of freely moving rats (sham, 8-Hz and 40-Hz sine-wave stimulation of the ventral/intermediate hippocampus, where 8- and 40-Hz stimulation were chosen to mimic naturally occurring hippocampal oscillations). Animals exhibited attenuated locomotor and exploratory activity upon stimulation at 40 Hz, but not at sham or 8-Hz stimulation. Such behavioral modifications were characterized by a significant reduction in rearing frequency, together with increased freezing behavior. Logistic regression analysis linked the observed changes in animal locomotion to 40-Hz electrical stimulation independently of time-related variables occurring during testing. Spectral analysis, conducted to monitor the electrophysiological profile in the CA1 area of the dorsal hippocampus, showed a significant reduction in peak theta frequency, together with reduced theta power in the 40-Hz vs. the sham stimulation animal group, independent of locomotion speed (theta range: 4–12 Hz). These findings contribute to the development of novel and safe medical protocols by indicating a strategy to constrain or optimize parameters in direct hippocampal electrical stimulation. PMID:24198322
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Experimental investigation of refractory metals in the premelting region during fast heating
NASA Astrophysics Data System (ADS)
Senchenko, V. N.; Belikov, R. S.; Popov, V. S.
2015-11-01
This work demonstrates experimental possibility of investigation of high refractory materials around its melting point, particularly in premelting region with high accuracy. In this article authors describe the developed experimental setup based on rapid resistive self-heating of a sample by a large current pulse generated by a capacitor discharge circuit that allow fast pulse interruption by temperature feedback signal. The sample temperature was measured with a two-channel microsecond radiation pyrometer. Preliminary experiments were conducted on tantalum and molybdenum at heating speed of 108 K/s. The method allows investigating thermophysical properties of refractory conductive materials such as melting temperature, melting heat, specific resistivity, specific enthalpy and specific heat capacity in solid and liquid phase, especially in premelting area.
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Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes
Hsieh, Peter Y.; Kwong, Kyei-Sing; Bennett, James
2015-09-27
Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. We measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometermore » and their ash fusion temperatures through optical image analysis. All measurements were made in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. An understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.« less
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Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hsieh, Peter Y.; Kwong, Kyei-Sing; Bennett, James
Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. We measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometermore » and their ash fusion temperatures through optical image analysis. All measurements were made in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. An understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.« less
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Bechard, Jeff; Gibson, John Ken; Killingsworth, Cheryl R; Wheeler, Jeffery J; Schneidkraut, Marlowe J; Huang, Jian; Ideker, Raymond E; McAfee, Donald A
2011-03-01
Vernakalant is a novel antiarrhythmic agent that has demonstrated clinical efficacy for the treatment of atrial fibrillation. Vernakalant blocks, to various degrees, cardiac sodium and potassium channels with a pattern that suggests atrial selectivity. We hypothesized, therefore, that vernakalant would affect atrial more than ventricular effective refractory period (ERP) and have little or no effect on ventricular defibrillation threshold (DFT). Atrial and ventricular ERP and ventricular DFT were determined before and after treatment with vernakalant or vehicle in 23 anesthetized male mixed-breed pigs. Vernakalant was infused at a rate designed to achieve stable plasma levels similar to those in human clinical trials. Atrial and ventricular ERP were determined by endocardial extrastimuli delivered to the right atria or right ventricle. Defibrillation was achieved using external biphasic shocks delivered through adhesive defibrillation patches placed on the thorax after 10 seconds of electrically induced ventricular fibrillation. The DFT was estimated using the Dixon "up-and-down" method. Vernakalant significantly increased atrial ERP compared with vehicle controls (34 ± 8 versus 9 ± 7 msec, respectively) without significantly affecting ventricular ERP or DFT. This is consistent with atrial selective actions and supports the conclusion that vernakalant does not alter the efficacy of electrical defibrillation.
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Gavrilescu, S; Luca, C; Streian, C; Lungu, G; Deutsch, G
1976-01-01
In 12 patients with manifest hypothyroidism right atrial monophasic action potentials showed a significant prolongation in comparison with data from normal or euthyroid patients. Atrial effective refractory periods were also significantly prolonged. After thyroid treatment the monophasic action potential duration and the effective refractory period of the right atrium were within normal ranges. In 6 hypothyroid patients studies of AV conduction with the aid of His bundle electrography and atrial pacing showed a supraHisian conduction delay which was manifest in one case and latent in another two. InfraHisian conduction delay was encountered in 2 cases. PMID:1008978
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Tobe, Satoshi; Yoshida, K; Adachi, K; Fukase, K; Tanimura, N; Yamaguchi, M
2008-03-01
A 65-year-old man was referred to our hospital to treat recent anterior myocardial infarction. Coronary artery angiography showed acute occlusion of left anterior descending coronary artery (LAD) and chronic occlusion of right coronary artery. After emergent percutaneous coronary intervention for LAD, drug-refractory electrical storm necessitating frequent electrical defibrillating cardioversion occurred. This patient successfully underwent surgical cryoablation, left ventriculoplasty and coronary revascularization. At 2 years and 10th month after the operation, he is well without limitation of daily activities and any evidence of myocardial ischemia and ventricular tachycardia.
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Simulation of meso-damage of refractory based on cohesion model and molecular dynamics method
NASA Astrophysics Data System (ADS)
Zhao, Jiuling; Shang, Hehao; Zhu, Zhaojun; Zhang, Guoxing; Duan, Leiguang; Sun, Xinya
2018-06-01
In order to describe the meso-damage of the refractories more accurately, and to study of the relationship between the mesostructured of the refractories and the macro-mechanics, this paper takes the magnesia-carbon refractories as the research object and uses the molecular dynamics method to instead the traditional sequential algorithm to establish the meso-particles filling model including small and large particles. Finally, the finite element software-ABAQUS is used to conducts numerical simulation on the meso-damage evolution process of refractory materials. From the results, the process of initiation and propagation of microscopic interface cracks can be observed intuitively, and the macroscopic stress-strain curve of the refractory material is obtained. The results show that the combination of molecular dynamics modeling and the use of Python in the interface to insert the cohesive element numerical simulation, obtaining of more accurate interface parameters through parameter inversion, can be more accurate to observe the interface of the meso-damage evolution process and effective to consider the effect of the mesostructured of the refractory material on its macroscopic mechanical properties.
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Electric current focusing efficiency in a graphene electric lens.
Mu, Weihua; Zhang, Gang; Tang, Yunqing; Wang, Wei; Ou-Yang, Zhongcan
2011-12-14
In the present work, we study theoretically the electron wave's focusing phenomenon in a single-layered graphene pn junction (PNJ) and obtain the electric current density distribution of graphene PNJ, which is in good agreement with the qualitative result in previous numerical calculations (Cheianov et al 2007 Science, 315, 1252). In addition, we find that, for a symmetric PNJ, 1/4 of total electric current radiated from the source electrode can be collected by the drain electrode. Furthermore, this ratio reduces to 3/16 in a symmetric graphene npn junction. Our results obtained by the present analytical method provide a general design rule for an electric lens based on negative refractory index systems. © 2011 IOP Publishing Ltd
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Epithelial conduction in hydromedusae.
Mackie, G O; Passano, L M
1968-09-01
Sarsia, Euphysa, and other hydromedusae have been studied by electrophysiological techniques and are found to have nonnervous conducting epithelia resembling those described earlier for siphonophores. Simple, nonmuscular epithelia fire singly or repetitively following brief electrical stimuli. The pulses recorded with suction electrodes are biphasic, initially positive, and show amplitudes of 0.75-2.0 mv, durations of 5-15 msec, and velocities of 15-35 cm/sec with short refractory periods. In the swimming muscle (myoepithelium) 2.0-4.0 mv composite events lasting 150-300 msec are associated with contraction waves. Propagation in nonnervous epithelia is typically all-or-none, nondecremental, and unpolarized. The subumbrellar endoderm lamella conducts independently of the adjacent ectoderm. The lower regions of the tentacles do not show propagated epithelial events. The spread of excitation in conducting epithelia and associated effector responses are described. Examples are given of interaction between events seemingly conducted in the nervous system and those in nonnervous epithelia. Either system may excite the other. Spontaneous activity, however, appears to originate in the nervous system. Conduction in nonnervous tissues is unaffected by excess Mg(++) in concentrations suppressing presumed nervous activity, although this may not be a wholly adequate criterion for distinguishing components of the two systems. Evidence from old work by Romanes is considered in the light of these findings and the general significance of epithelial conduction is discussed.
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Thermophotovoltaic energy conversion using photonic bandgap selective emitters
Gee, James M.; Lin, Shawn-Yu; Fleming, James G.; Moreno, James B.
2003-06-24
A method for thermophotovoltaic generation of electricity comprises heating a metallic photonic crystal to provide selective emission of radiation that is matched to the peak spectral response of a photovoltaic cell that converts the radiation to electricity. The use of a refractory metal, such as tungsten, for the photonic crystal enables high temperature operation for high radiant flux and high dielectric contrast for a full 3D photonic bandgap, preferable for efficient thermophotovoltaic energy conversion.
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Facilitation and refractoriness of the electrically evoked compound action potential.
Hey, Matthias; Müller-Deile, Joachim; Hessel, Horst; Killian, Matthijs
2017-11-01
In this study we aim to resolve the contributions of facilitation and refractoriness at very short pulse intervals. Measurements of the refractory properties of the electrically evoked compound action potential (ECAP) of the auditory nerve in cochlear implant (CI) users at inter pulse intervals below 300 μs are influenced by facilitation and recovery effects. ECAPs were recorded using masker pulses with a wide range of current levels relative to the probe pulse levels, for three suprathreshold probe levels and pulse intervals from 13 to 200 μs. Evoked potentials were measured for 21 CI patients by using the masked response extraction artifact cancellation procedure. During analysis of the measurements the stimulation current was not used as absolute value, but in relation to the patient's individual ECAP threshold. This enabled a more general approach to describe facilitation as a probe level independent effect. Maximum facilitation was found for all tested inter pulse intervals at masker levels near patient's individual ECAP threshold, independent from probe level. For short inter pulse intervals an increased N 1 P 1 amplitude was measured for subthreshold masker levels down to 120 CL below patient's individual ECAP threshold in contrast to the recreated state. ECAPs recorded with inter pulse intervals up to 200 μs are influenced by facilitation and recovery. Facilitation effects are most pronounced for masker levels at or below ECAP threshold, while recovery effects increase with higher masker levels above ECAP threshold. The local maximum of the ECAP amplitude for masker levels around ECAP threshold can be explained by the mutual influence of maximum facilitation and minimal refractoriness. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.
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Dal Magro, Fabio; Xu, Haoxin; Nardin, Gioacchino; Romagnoli, Alessandro
2018-03-01
This study reports the thermal analysis of a novel thermal energy storage based on high temperature phase change material (PCM) used to improve efficiency in waste-to-energy plants. Current waste-to-energy plants efficiency is limited by the steam generation cycle which is carried out with boilers composed by water-walls (i.e. radiant evaporators), evaporators, economizers and superheaters. Although being well established, this technology is subjected to limitations related with high temperature corrosion and fluctuation in steam production due to the non-homogenous composition of solid waste; this leads to increased maintenance costs and limited plants availability and electrical efficiency. The proposed solution in this paper consists of replacing the typical refractory brick installed in the combustion chamber with a PCM-based refractory brick capable of storing a variable heat flux and to release it on demand as a steady heat flux. By means of this technology it is possible to mitigate steam production fluctuation, to increase temperature of superheated steam over current corrosion limits (450°C) without using coated superheaters and to increase the electrical efficiency beyond 34%. In the current paper a detailed thermo-mechanical analysis has been carried out in order to compare the performance of the PCM-based refractory brick against the traditional alumina refractory bricks. The PCM considered in this paper is aluminium (and its alloys) whereas its container consists of high density ceramics (such as Al 2 O 3 , AlN and Si 3 N 4 ); the different coefficient of linear thermal expansion for the different materials requires a detailed thermo-mechanical analysis to be carried out to ascertain the feasibility of the proposed technology. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Cavus, Idil; Widi, Gabriel A; Duckrow, Robert B; Zaveri, Hitten; Kennard, Jeremy T; Krystal, John; Spencer, Dennis D
2016-02-01
The effect of electrical stimulation on brain glutamate release in humans is unknown. Glutamate is elevated at baseline in the epileptogenic hippocampus of patients with refractory epilepsy, and increases during spontaneous seizures. We examined the effect of 50 Hz stimulation on glutamate release and its relationship to interictal levels in the hippocampus of patients with epilepsy. In addition, we measured basal and stimulated glutamate levels in a subset of these patients where stimulation elicited a seizure. Subjects (n = 10) were patients with medically refractory epilepsy who were undergoing intracranial electroencephalography (EEG) evaluation in an epilepsy monitoring unit. Electrical stimulation (50 Hz) was delivered through implanted hippocampal electrodes (n = 11), and microdialysate samples were collected every 2 min. Basal glutamate, changes in glutamate efflux with stimulation, and the relationships between peak stimulation-associated glutamate concentrations, basal zero-flow levels, and stimulated seizures were examined. Stimulation of epileptic hippocampi in patients with refractory epilepsy caused increases in glutamate efflux (p = 0.005, n = 10), and 4 of ten patients experienced brief stimulated seizures. Stimulation-induced increases in glutamate were not observed during the evoked seizures, but rather were related to the elevation in interictal basal glutamate (R(2) = 0.81, p = 0.001). The evoked-seizure group had lower basal glutamate levels than the no-seizure group (p = 0.04), with no stimulation-induced change in glutamate efflux (p = 0.47, n = 4). Conversely, increased glutamate was observed following stimulation in the no-seizure group (p = 0.005, n = 7). Subjects with an atrophic hippocampus had higher basal glutamate levels (p = 0.03, n = 7) and higher stimulation-induced glutamate efflux. Electrical stimulation of the epileptic hippocampus either increased extracellular glutamate efflux or induced seizures. The magnitude of stimulated glutamate increase was related to elevation in basal interictal glutamate, suggesting a common mechanism, possibly impaired glutamate metabolism. Divergent mechanisms may exist for seizure induction and increased glutamate in patients with epilepsy. These data highlight the potential risk of 50 Hz stimulation in patients with epilepsy. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.
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Shao, Yiye; Wang, Cuicui; Hong, Zhen; Chen, Yinghui
2016-03-01
It is widely recognized that P-glycoprotein (P-gp) mediates drug resistance in refractory epilepsy. However, the molecular mechanism underlying the up-regulation of P-gp expression remains unclear. Our previous studies have demonstrated that p38 mitogen-activated protein kinase (MAPK) regulates P-gp expression in cultured K562 cells. However, a lack of in vivo research leaves unanswered questions regarding whether p38MAPK regulates P-gp expression or drug resistance in refractory epilepsy. This in vivo study examined the effects of p38MAPK on the expression of P-gp and mdr1 in the rat brain and quantified antiepileptic drug (AED) concentrations in the hippocampal extracellular fluid. In addition, the role of p38MAPK in electrical and behavioral activity in a rat epilepsy model was studied. The results indicated that p38MAPK inhibition by SB202190 reduced P-gp expression, while increasing AED concentration in the hippocampal extracellular fluid in refractory epileptic rats. SB202190 also reduced the resistance to AEDs in drug-resistant rats and significantly reduced the severity of seizure activity. These results suggest that p38MAPK could participate in drug resistance in refractory epilepsy through the regulation of P-gp. We show that the specific inhibitor of p38MAPK could down-regulate the expression of multidrug transporter (P-glycoprotein) in blood-brain barrier, increase the concentration of antiepileptic drugs in the hippocampal extracellular fluid and reduce anti-epileptic drug resistance in refractory epileptic rats. We propose that the p38MAPK signaling pathway participates in drug resistance in refractory epilepsy through the regulation of P-glycoprotein expression. © 2015 International Society for Neurochemistry.
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Thermally Simulated Testing of a Direct-Drive Gas-Cooled Nuclear Reactor
NASA Technical Reports Server (NTRS)
Godfroy, Thomas; Bragg-Sitton, Shannon; VanDyke, Melissa
2003-01-01
This paper describes the concept and preliminary component testing of a gas-cooled, UN-fueled, pin-type reactor which uses He/Xe gas that goes directly into a recuperated Brayton system to produce electricity for nuclear electric propulsion. This Direct-Drive Gas-Cooled Reactor (DDG) is designed to be subcritical under water or wet-sand immersion in case of a launch accident. Because the gas-cooled reactor can directly drive the Brayton turbomachinery, it is possible to configure the system such that there are no external surfaces or pressure boundaries that are refractory metal, even though the gas delivered to the turbine is 1144 K. The He/Xe gas mixture is a good heat transport medium when flowing, and a good insulator when stagnant. Judicious use of stagnant cavities as insulating regions allows transport of the 1144-K gas while keeping all external surfaces below 900 K. At this temperature super-alloys (Hastelloy or Inconel) can be used instead of refractory metals. Super-alloys reduce the technology risk because they are easier to fabricate than refractory metals, we have a much more extensive knowledge base on their characteristics, and, because they have a greater resistance to oxidation, system testing is eased. The system is also relatively simple in its design: no additional coolant pumps, heat exchanger, or freeze-thaw systems are required. Key to success of this concept is a good knowledge of the heat transfer between the fuel pins and the gas, as well as the pressure drop through the system. This paper describes preliminary testing to obtain this key information, as well as experience in demonstrating electrical thermal simulation of reactor components and concepts.
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Direct-Drive Gas-Cooled Reactor Power System: Concept and Preliminary Testing
NASA Technical Reports Server (NTRS)
Wright, S. A.; Lipinski, R. J.; Godfroy, T. J.; Bragg-Sitton, S. M.; VanDyke, M. K.
2002-01-01
This paper describes the concept and preliminary component testing of a gas-cooled, UN-fueled, pin-type reactor which uses He/Xe gas that goes directly into a recuperated Brayton system to produce electricity for nuclear electric propulsion. This Direct-Drive Gas-Cooled Reactor (DDG) is designed to be subcritical under water or wet- sand immersion in case of a launch accident. Because the gas-cooled reactor can directly drive the Brayton turbomachinery, it is possible to configure the system such that there are no external surfaces or pressure boundaries that are refractory metal, even though the gas delivered to the turbine is 1144 K. The He/Xe gas mixture is a good heat transport medium when flowing, and a good insulator when stagnant. Judicious use of stagnant cavities as insulating regions allows transport of the 1144-K gas while keeping all external surfaces below 900 K. At this temperature super-alloys (Hastelloy or Inconel) can be used instead of refractory metals. Super-alloys reduce the technology risk because they are easier to fabricate than refractory metals, we have a much more extensive knowledge base on their characteristics, and, because they have a greater resistance to oxidation, system testing is eased. The system is also relatively simple in its design: no additional coolant pumps, heat exchanger, or freeze-thaw systems are required. Key to success of this concept is a good knowledge of the heat transfer between the fuel pins and the gas, as well as the pressure drop through the system. This paper describes preliminary testing to obtain this key information, as well as experience in demonstrating electrically heated testing of simulated reactor components.
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[Dust and silica exposure on metallurgical furnace maintenance using refractory materials].
Garattini, S; Barbieri, P G; Bottone, F; Brunelli, E; Carminati, F; Chiari, R; Sarnico, M
2012-01-01
In the metallurgical industries the silica risk has long been known, particularly for the refractoryes maintenance workers. The maintenance of furnaces, ladles and tundisches refractory linings, on the current organization of production, is provided by companies under contract. The information available about the characterization of risk for this group of workers are at present inadequate. The study investigates the exposure to dust, also containing free crystalline silica (SLC), through the analysis of samples of commercial products used in the reconstruction of refractory linings of furnaces, ladles and tundisches, materials from the demolition of refractory articles and dust from work areas. It also presents the results of an environmental investigation conducted during the demolition and reconstruction of the refractory in three steel mills. The Authors, by the numerous inspections and the systematic survey of working conditions, have formulated a SLC risk profile and some proposals for prevention.
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Pereira Junior, Bernardo de Sampaio; Nunes, Paula; Benseñor, Isabela Martins; Lotufo, Paulo Andrade; Machado-Vieira, Rodrigo; Brunoni, André R.
2015-01-01
Background. Bipolar depression (BD) is a prevalent condition, with poor therapeutic options and a high degree of refractoriness. This justifies the development of novel treatment strategies, such as transcranial direct current stimulation (tDCS) that showed promising results in unipolar depression. Methods. We describe a randomized, sham-controlled, double-blinded trial using tDCS for refractory, acutely symptomatic BD (the bipolar depression electrical treatment trial, BETTER). Sixty patients will be enrolled and assessed with clinical and neuropsychological tests. The primary outcome is change (over time and across groups) in the scores of the Hamilton Depression Rating Scale (17 items). Biological markers such as blood neurotrophins and interleukins, genetic polymorphisms, heart rate variability, and motor cortical excitability will be assessed. Twelve anodal-left/cathodal-right 2 mA tDCS sessions over the dorsolateral prefrontal cortex will be performed in 6 weeks. Results. In the pilot phase, five patients received active tDCS and were double-blindly assessed, two presenting clinical response. TDCS was well-tolerated, with no changes in cognitive scores. Conclusion. This upcoming clinical trial will address the efficacy of tDCS for BD on different degrees of refractoriness. The evaluation of biological markers will also help in understanding the pathophysiology of BD and the mechanisms of action of tDCS. PMID:25878904
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A Network Model for the Effective Thermal Conductivity of Rigid Fibrous Refractory Insulations
NASA Technical Reports Server (NTRS)
Marschall, Jochen; Cooper, D. M. (Technical Monitor)
1995-01-01
A procedure is described for computing the effective thermal conductivity of a rigid fibrous refractory insulation. The insulation is modeled as a 3-dimensional Cartesian network of thermal conductance. The values and volume distributions of the conductance are assigned to reflect the physical properties of the insulation, its constituent fibers, and any permeating gas. The effective thermal conductivity is computed by considering the simultaneous energy transport by solid conduction, gas conduction and radiation through a cubic volume of model insulation; thus the coupling between heat transfer modes is retained (within the simplifications inherent to the model), rather than suppressed by treating these heat transfer modes as independent. The model takes into account insulation composition, density and fiber anisotropy, as well as the geometric and material properties of the constituent fibers. A relatively good agreement, between calculated and experimentally derived thermal conductivity values, is obtained for a variety of rigid fibrous insulations.
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ERIC Educational Resources Information Center
Miller, Julie Ann
1977-01-01
Describes use of electronic model to simulate electrical patterns resulting from nerve cell interactions in the brain. Resembles nerve cell activity realistically in that the model produces signals above a set threshold, its firing activity varies, a refractory period is required before second firing, and it displays plasticity. (CS)
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Early bioelectric activities mediate redox-modulated regeneration
Ferreira, Fernando; Luxardi, Guillaume; Reid, Brian
2016-01-01
Reactive oxygen species (ROS) and electric currents modulate regeneration; however, the interplay between biochemical and biophysical signals during regeneration remains poorly understood. We investigate the interactions between redox and bioelectric activities during tail regeneration in Xenopus laevis tadpoles. We show that inhibition of NADPH oxidase-mediated production of ROS, or scavenging or blocking their diffusion into cells, impairs regeneration and consistently regulates the dynamics of membrane potential, transepithelial potential (TEP) and electric current densities (JI) during regeneration. Depletion of ROS mimics the altered TEP and JI observed in the non-regenerative refractory period. Short-term application of hydrogen peroxide (H2O2) rescues (from depleted ROS) and induces (from the refractory period) regeneration, TEP increase and JI reversal. H2O2 is therefore necessary for and sufficient to induce regeneration and to regulate TEP and JI. Epistasis assays show that voltage-gated Na+ channels act downstream of H2O2 to modulate regeneration. Altogether, these results suggest a novel mechanism for regeneration via redox-bioelectric orchestration. PMID:27827821
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Sarkisov, G. S.; Rosenthal, S. E.; Struve, K. W.
For nanosecond electrical explosion of fine metal wires in vacuum generates calibrated, radially expanded gas cylinders of metal atoms are surrounded by low-density fast expanding plasma corona. Here, a novel integrated-phase technique, based on laser interferometry, provides the dynamic dipole polarizability of metal atoms. This data was previously unavailable for tungsten atoms. Furthermore, an extremely high melting temperature and significant pre-melt electronic emission make these measurements particularly complicated for this refractory metal.
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Elevated temperature strain gages
NASA Technical Reports Server (NTRS)
Brittain, J. O.; Geslin, D.; Lei, J. F.
1986-01-01
One of the goals of the HOST Program is the development of electrical resistance strain gages for static strain measurements at temperatures equal to or greater than 1273 K. Strain gage materials must have a reproducible or predictable response to temperature, time and strain. It is the objective of this research to investigate criteria for the selection of materials for such applications through electrical properties studies. The results of the investigation of two groups of materials, refractory compounds and binary alloy solid solutions are presented.
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Sarkisov, G. S.; Rosenthal, S. E.; Struve, K. W.
2016-10-12
For nanosecond electrical explosion of fine metal wires in vacuum generates calibrated, radially expanded gas cylinders of metal atoms are surrounded by low-density fast expanding plasma corona. Here, a novel integrated-phase technique, based on laser interferometry, provides the dynamic dipole polarizability of metal atoms. This data was previously unavailable for tungsten atoms. Furthermore, an extremely high melting temperature and significant pre-melt electronic emission make these measurements particularly complicated for this refractory metal.
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Code of Federal Regulations, 2014 CFR
2014-07-01
... introduced and that uses electrical energy to heat the reverberatory furnace slag to such a temperature... removal of ground, pavement, concrete, or asphalt. Materials storage and handling area means any area of a.... Reverberatory furnace means a refractory-lined furnace that uses one or more flames to heat the walls and roof...
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Code of Federal Regulations, 2013 CFR
2013-07-01
... introduced and that uses electrical energy to heat the reverberatory furnace slag to such a temperature... removal of ground, pavement, concrete, or asphalt. Materials storage and handling area means any area of a.... Reverberatory furnace means a refractory-lined furnace that uses one or more flames to heat the walls and roof...
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Code of Federal Regulations, 2012 CFR
2012-07-01
... introduced and that uses electrical energy to heat the reverberatory furnace slag to such a temperature... removal of ground, pavement, concrete, or asphalt. Materials storage and handling area means any area of a.... Reverberatory furnace means a refractory-lined furnace that uses one or more flames to heat the walls and roof...
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2014-01-01
Background Refractory angina is a severe chronic disease, defined as angina which cannot be controlled by usual treatments for heart disease. This disease is frightening, debilitating, and difficult to manage. Many people suffering refractory have inadequate pain relief, continually revisit emergency departments for help, undergo repeated cardiac investigations, and struggle with obtaining appropriate care. There is no clear framework to help people understand the risks and benefits of available treatment options in Canada. Some treatments for refractory angina are invasive, while others are not covered by provincial health insurance plans. Effective care for refractory angina sufferers in Canada is critically underdeveloped; it is important that healthcare professionals and refractory angina sufferers alike understand the treatment options and their implications. This proposal builds on the recent Canadian practice guidelines for the management of refractory angina. We propose to develop a decision support tool in order to help people suffering from refractory angina make well-informed decisions about their healthcare and reduce their uncertainty about treatment options. Methods This project will be conducted in three phases: a) development of the support tool with input from clinical experts, the Canadian refractory angina guidelines, and people living with refractory angina, b) pilot testing of the usability of the tool, and c) formal preliminary evaluation of the effectiveness of the support tool to help people make informed decisions about treatment options. Discussion A decision support tool for refractory angina is needed and the available data suggest that by developing such a tool, we may be able to help refractory angina sufferers better understand their condition and the effectiveness of available treatment options (in their respective clinical settings) as well as their implications (e.g. risks vs. benefits). By virtue of this tool, we may also be able to facilitate identification and inclusion of patients’ values and preferences in the decision making process. This is particularly important as refractory angina is an intractable condition, necessitating that the selected course of treatment be lifelong. This study will yield a much needed patient decision aid for people living with refractory angina and pilot data to support a subsequent effectiveness study. PMID:24920518
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Lightweight alumina refractory aggregate. Final report
DOE Office of Scientific and Technical Information (OSTI.GOV)
Swansiger, T.G.; Pearson, A.
1996-07-16
Objective was to develop a lightweight, high alumina refractory aggregate for use in various high performance insulating (low thermal conductivity) refractory applications (e.g., in the aluminium, glass, cement, and iron and steel industries). A new aggregate process was developed through bench and pilot-scale experiments involving extrusion of a blend of calcined and activated alumina powders and organic extrusion aids and binders. The aggregate, with a bulk density approaching 2.5 g/cc, exhibited reduced thermal conductivity and adequate fired strength compared to dense tabular aggregate. Refractory manufacturers were moderately enthusiastic over the results. Alcoa prepared an economic analysis for producing lightweight aggregate,more » based on a retrofit of this process into existing Alcoa production facilities. However, a new, competing lightweight aggregate material was developed by another company; this material (Plasmal{trademark})had a significantly more favorable cost base than the Alcoa/DOE material, due to cheap raw materials and fewer processing steps. In late 1995, Alcoa became a distributor of Plasmal. Alcoa estimated that {ge}75% of the market originally envisioned for the Alcoa/DOE aggregate would be taken by Plasmal. Hence, it was decided to terminate the contract without the full- scale demonstration.« less
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Epithelial Conduction in Hydromedusae
Mackie, G. O.; Passano, L. M.
1968-01-01
Sarsia, Euphysa, and other hydromedusae have been studied by electrophysiological techniques and are found to have nonnervous conducting epithelia resembling those described earlier for siphonophores. Simple, nonmuscular epithelia fire singly or repetitively following brief electrical stimuli. The pulses recorded with suction electrodes are biphasic, initially positive, and show amplitudes of 0.75–2.0 mv, durations of 5–15 msec, and velocities of 15–35 cm/sec with short refractory periods. In the swimming muscle (myoepithelium) 2.0–4.0 mv composite events lasting 150–300 msec are associated with contraction waves. Propagation in nonnervous epithelia is typically all-or-none, nondecremental, and unpolarized. The subumbrellar endoderm lamella conducts independently of the adjacent ectoderm. The lower regions of the tentacles do not show propagated epithelial events. The spread of excitation in conducting epithelia and associated effector responses are described. Examples are given of interaction between events seemingly conducted in the nervous system and those in nonnervous epithelia. Either system may excite the other. Spontaneous activity, however, appears to originate in the nervous system. Conduction in nonnervous tissues is unaffected by excess Mg++ in concentrations suppressing presumed nervous activity, although this may not be a wholly adequate criterion for distinguishing components of the two systems. Evidence from old work by Romanes is considered in the light of these findings and the general significance of epithelial conduction is discussed. PMID:19873635
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Epithelial Conduction in Hydromedusae
Mackie, G. O.; Passano, L. M.
1968-01-01
Sarsia, Euphysa, and other hydromedusae have been studied by electrophysiological techniques and are found to have nonnervous conducting epithelia resembling those described earlier for siphonophores. Simple, non-muscular epithelia fire singly or repetitively following brief electrical stimuli. The pulses recorded with suction electrodes are biphasic, initially positive, and show amplitudes of 0.75–2.0 mv, durations of 5–15 msec, and velocities of 15–35 cm/sec with short refractory periods. In the swimming muscle (myoepithelium) 2.0–4.0 mv composite events lasting 150–300 msec are associated with contraction waves. Propagation in nonnervous epithelia is typically all-or-none, nondecremental, and unpolarized. The subumbrellar endoderm lamella conducts independently of the adjacent ectoderm. The lower regions of the tentacles do not show propagated epithelial events. The spread of excitation in conducting epithelia and associated effector responses are described. Examples are given of interaction between events seemingly conducted in the nervous system and those in nonnervous epithelia. Either system may excite the other. Spontaneous activity, however, appears to originate in the nervous system. Conduction in nonnervous tissues is unaffected by excess Mg++ in concentrations suppressing presumed nervous activity, although this may not be a wholly adequate criterion for distinguishing components of the two systems. Evidence from old work by Romanes is considered in the light of these findings and the general significance of epithelial conduction is discussed. PMID:4386662
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Epithelial conduction in hydromedusae.
Mackie, G O; Passano, L M
1968-10-01
Sarsia, Euphysa, and other hydromedusae have been studied by electrophysiological techniques and are found to have nonnervous conducting epithelia resembling those described earlier for siphonophores. Simple, non-muscular epithelia fire singly or repetitively following brief electrical stimuli. The pulses recorded with suction electrodes are biphasic, initially positive, and show amplitudes of 0.75-2.0 mv, durations of 5-15 msec, and velocities of 15-35 cm/sec with short refractory periods. In the swimming muscle (myoepithelium) 2.0-4.0 mv composite events lasting 150-300 msec are associated with contraction waves. Propagation in nonnervous epithelia is typically all-or-none, nondecremental, and unpolarized. The subumbrellar endoderm lamella conducts independently of the adjacent ectoderm. The lower regions of the tentacles do not show propagated epithelial events. The spread of excitation in conducting epithelia and associated effector responses are described. Examples are given of interaction between events seemingly conducted in the nervous system and those in nonnervous epithelia. Either system may excite the other. Spontaneous activity, however, appears to originate in the nervous system. Conduction in nonnervous tissues is unaffected by excess Mg(++) in concentrations suppressing presumed nervous activity, although this may not be a wholly adequate criterion for distinguishing components of the two systems. Evidence from old work by Romanes is considered in the light of these findings and the general significance of epithelial conduction is discussed.
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Corino, Valentina D A; Sandberg, Frida; Platonov, Pyotr G; Mainardi, Luca T; Ulimoen, Sara R; Enger, Steve; Tveit, Arnljot; Sörnmo, Leif
2014-11-01
During atrial fibrillation (AF), conventional electrophysiological techniques for assessment of refractory period or conduction velocity of the atrioventricular (AV) node cannot be used. We aimed at evaluating changes in AV nodal properties during administration of metoprolol from electrocardiogram data, and to support our findings with simulated data based on results from an electrophysiological study. Sixty patients (age 71 ± 9 years, 42 men) with permanent AF were included in the RATe control in Atrial Fibrillation (RATAF) study. Two 15 min segments, during baseline and metoprolol administration, starting at 2 pm were analysed in this study. Atrial fibrillatory rate (AFR), heart rate (HR), and AV nodal parameters were assessed. The AV nodal parameters account for the probability of an impulse not taking the fast pathway, the absolute refractory periods of the slow and fast pathways (aRPs and aRPf), representing the functional refractory period, and their respective prolongation in refractory period. In addition, simulated RR series were generated that mimic metoprolol administration through prolonged AV conduction interval and AV node effective refractory period. During metoprolol administration, AFR and HR were significantly decreased and aRP was significantly prolonged in both pathways (aRPs: 337 ± 60 vs. 398 ± 79 ms, P < 0.01; aRPf: 430 ± 91 vs. 517 ± 100 ms, P < 0.01). Similar results were found for the simulated RR series, both aRPs and aRPf being prolonged with metoprolol (aRPs: 413 ± 33 vs. 437 ± 43 ms, P = 0.01; aRPf: 465 ± 40 vs. 502 ± 69 ms, P = 0.02). The AV nodal parameters reflect expected changes after metoprolol administration, i.e. a prolongation in functional refractory period. The simulations confirmed that aRPs and aRPf may serve as an estimate of the functional refractory period. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.
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NASA Technical Reports Server (NTRS)
Phillips, W. M. (Inventor)
1978-01-01
High temperature oxidation resistance, high hardness and high abrasion and wear resistance are properties of cermet compositions particularly to provide high temperature resistant refractory coatings on metal substrates, for use as electrical insulation seals for thermionic converters. The compositions comprise a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride are also described.
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Stimulant-Responsive and Stimulant-Refractory Aggressive Behavior Among Children with ADHD
Blader, Joseph C.; Pliszka, Steven R.; Jensen, Peter S.; Schooler, Nina R.; Kafantaris, Vivian
2010-01-01
OBJECTIVES The objective of this study was to examine factors that are associated with aggression that is responsive versus refractory to individualized optimization of stimulant monotherapy among children with attention-deficit/hyperactivity disorder (ADHD). METHODS Children who were aged 6 to 13 years and had ADHD, either oppositional defiant disorder or conduct disorder, significant aggressive behavior, and a history of insufficient response to stimulants completed an open stimulant monotherapy optimization protocol. Stimulant titration with weekly assessments of behavior and tolerability identified an optimal regimen for each child. Families also received behavioral therapy. Parents completed the Retrospective-Modified Overt Aggression Scale (R-MOAS) at each visit. Children were classified as having stimulant-refractory aggression on the basis of R-MOAS ratings and clinician judgment. Differences that pertained to treatment, demographic, and psychopathology between groups with stimulant monotherapy–responsive and –refractory aggression were evaluated. RESULTS Aggression among 32 (49.3%) of 65 children was reduced sufficiently after stimulant dosage adjustment and behavioral therapy to preclude adjunctive medication. Those who responded to stimulant monotherapy were more likely to benefit from the protocol’s methylphenidate preparation (once-daily, triphasic release), showed a trend for lower average dosages, and received fewer behavioral therapy sessions than did children with stimulant-refractory aggression. Boys, especially those with higher ratings of baseline aggression and of depressive and manic symptoms, more often exhibited stimulant-refractory aggression. CONCLUSIONS Among children whose aggressive behavior develops in the context of ADHD and of oppositional defiant disorder or conduct disorder, and who had insufficient response to previous stimulant treatment in routine clinical care, systematic, well-monitored titration of stimulant monotherapy often culminates in reduced aggression that averts the need for additional agents. PMID:20837589
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Miwa, Yosuke; Ikeda, Takanori; Mera, Hisaaki; Miyakoshi, Mutsumi; Hoshida, Kyoko; Yanagisawa, Ryoji; Ishiguro, Haruhisa; Tsukada, Takehiro; Abe, Atsuko; Yusu, Satoru; Yoshino, Hideaki
2010-05-01
Occasionally it is difficult to inhibit electrical storm (ES) with standard pharmacological treatment. In the present study the effect of landiolol, an ultra-short-acting beta(1)-selective blocker, on ES refractory to class III antiarrhythmic drugs was evaluated. The study group comprised 42 consecutive patients who developed ES for which intravenous class III antiarrhythmic drugs, such as amiodarone and nifekalant, were ineffective. Landiolol was administered intravenously with an initial dose of 2.5 microg x kg(-1) x min(-1), which was doubled if it was ineffective, up to a maximum dose of 80 microg x kg(-1) x min(-1). Landiolol inhibited ES in 33 patients (79%) at a mean dose of 7.5+/-12.2 microg x kg(-1) x min(-1). All patients in whom landiolol was ineffective died of arrhythmia. Of the 33 patients in whom landiolol was effective, 25 survived and were discharged (60% of all patients). Landiolol significantly decreased heart rate (P<0.0001), but did not affect blood pressure. Landiolol was not discontinued for adverse effects in any of the responders. Age, APACHE II score, and pH of arterial blood gas differed significantly between the responders and nonresponders. Landiolol is useful as a life-saving drug for class III antiarrhythmic drug-resistant ES. The main mechanism of ES refractory to class III antiarrhythmic drugs could be abnormal automaticity but not reentry.
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Enhanced electro-Fenton Mineralization of Acid Orange 7 Using a Carbon Nanotube Fiber Based Cathode
NASA Astrophysics Data System (ADS)
Huong Le, Thi Xuan; Alemán, Belén; Vilatela, Juan J.; Bechelany, Mikhael; Cretin, Marc
2018-02-01
A new cathodic material for electro-Fenton (EF) process was prepared based on a macroscopic fiber (CNTF) made of mm long carbon nanotubes directly spun from the gas phase by floating catalyst CVD, on a carbon fiber (CF) substrate. CNTF@CF electrode is a highly graphitic material combining a high surface area ( 260 m2/g) with high electrical conductivity and electrochemical stability . One kind of azo dye, acid orange 7 (AO7), was used as model bio-refractory pollutant to be treated at CNTF@CF cathode in acidic aqueous medium (pH 3.0). The experimental results pointed out that AO7 and its organic intermediate compounds were totally mineralized by hydroxyl radical generated from Fenton reaction. In fact, 96.7 % of the initial TOC was eliminated in 8h of electrolysis by applying a current of -25 mA and ferrous ions as catalyst at concentration of 0.2 mM. At the same electrolysis time, only 23.7 % of TOC removal found on CF support which proved the high mineralization efficiency of new material thanks to CNTs deposition. The CNTF@CF cathode maintained stable its activity during five experimental cycles of EF set-up. The results indicated that CNTF@CF material could be a potential choice for wastewater treatment containing bio-refractory by electrochemical advanced oxidation processes (EAOPs).
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[Sacral neuromodulation in urology - development and current status].
Schwalenberg, T; Stolzenburg, J-U; Kriegel, C; Gonsior, A
2012-01-01
Sacral neuromodulation (SNM) in urology is employed to treat refractory lower urinary tract dysfunction as well as chronic pelvic pain. Electrical stimulation of the sacral afferents (S2 - S4) causes activation and conditioning of higher autonomic and somatic neural structures and thereby influences the efferents controlling the urinary bladder, the rectum and their related sphincter systems. It is therefore possible to treat overactivity as well as hypocontractility and functional bladder neck obstruction. SNM treatment is conducted biphasically. Initially, test electrodes are placed to evaluate changes in micturition and pain parameters. If, in this first phase - called peripheral nerve evaluation (PNE test) - sufficient improvements are observed, the patient progresses to phase two which involves implantation of the permanent electrodes and impulse generator system. In recent years, the "two stage approach" with initial implantation of the permanent electrodes has been favoured as it increases treatment success rates. Long-term success rates of SNM vary significantly in the literature (50 - 80 %) due to heterogeneous patient populations as well as improved surgical approaches. With the introduction of "tined lead electrodes" (2002), tissue damage is reduced to a minimum. Technical innovation, financial feasibility (reimbursed in Germany since 2004) and wider application, especially in otherwise therapy-refractory patients or complex dysfunctions of the pelvis, have established SNM as a potent treatment option in urology. © Georg Thieme Verlag KG Stuttgart · New York.
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Sakamoto, Tamotsu; Fujiki, Akira; Nakatani, Yosuke; Sakabe, Masao; Mizumaki, Koichi; Hashimoto, Norio; Inoue, Hiroshi
2009-10-01
This study evaluated antiarrhythmic effects of d,l-sotalol in a canine atrial fibrillation (AF) model with left ventricular dysfunction. Thirteen beagles (Sotalol group n=7 and Control group n=6) were subjected to atrial tachypacing (ATP) (400 beats/min) with intact atrioventricular conduction for 4 weeks. Oral d,l-sotalol (2 mg/kg) was administered 1 week after starting ATP and continued throughout the experiment. One week after starting ATP, atrial effective refractory periods (AERPs) were shortened in both groups. However, d,l-sotalol treatment gradually prolonged AERP, resulting in a significant prolongation of AERP compared with the Control group at 4 weeks (Control 76 +/-4 and Sotalol 126 +/-5 ms, p<0.01). d,l-Sotalol treatment showed lower AF inducibility and shorter AF duration at 4 weeks. In the control group, expressions of L-type Ca(2+) channel alpha1c and Kv4.3 mRNA were downregulated by 46.2% and 43.0%, respectively, after 4 weeks of ATP; d,l-sotalol treatment did not affect these changes. d,l-Sotalol treatment prolonged AERP, even after atrial electrical remodeling had developed, and prevented AF perpetuation without affecting downregulated expression of L-type Ca(2+) channel alpha1c and Kv4.3 mRNA in an ATP-induced canine AF model.
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Li, Zhan; Wang, Ximin; Wang, Weizong; Du, Juanjuan; Wei, Jinqiu; Zhang, Yong; Wang, Jiangrong; Hou, Yinglong
2017-07-01
Electrical remodeling has been reported to play a major role in the initiation and maintenance of atrial fibrillation (AF). Long non-coding RNAs (lncRNAs) have been increasingly recognized as contributors to the pathology of heart diseases. However, the roles and mechanisms of lncRNAs in electrical remodeling during AF remain unknown. In this study, the lncRNA expression profiles of right atria were investigated in AF and non-AF rabbit models by using RNA sequencing technique and validated using quantitative real-time polymerase chain reaction (qRT-PCR). A total of 99,843 putative new lncRNAs were identified, in which 1220 differentially expressed transcripts exhibited >2-fold change. Bioinformatics analysis was conducted to predict the functions and interactions of the aberrantly expressed genes. On the basis of a series of filtering pipelines, one lncRNA, TCONS_00075467, was selected to explore its effects and mechanisms on electrical remodeling. The atrial effective refractory period was shortened in vivo and the L-type calcium current and action potential duration were decreased in vitro by silencing of TCONS_00075467 with lentiviruses. Besides, the expression of miRNA-328 was negatively correlated with TCONS_00075467. We further demonstrated that TCONS_00075467 could sponge miRNA-328 in vitro and in vivo to regulate the downstream protein coding gene CACNA1C. In addition, miRNA-328 could partly reverse the effects of TCONS_00075467 on electrical remodeling. In summary, dysregulated lncRNAs may play important roles in modulating electrical remodeling during AF. Our study may facilitate the mechanism studies of lncRNAs in AF pathogenesis and provide potential therapeutic targets for AF. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Early bioelectric activities mediate redox-modulated regeneration.
Ferreira, Fernando; Luxardi, Guillaume; Reid, Brian; Zhao, Min
2016-12-15
Reactive oxygen species (ROS) and electric currents modulate regeneration; however, the interplay between biochemical and biophysical signals during regeneration remains poorly understood. We investigate the interactions between redox and bioelectric activities during tail regeneration in Xenopus laevis tadpoles. We show that inhibition of NADPH oxidase-mediated production of ROS, or scavenging or blocking their diffusion into cells, impairs regeneration and consistently regulates the dynamics of membrane potential, transepithelial potential (TEP) and electric current densities (J I ) during regeneration. Depletion of ROS mimics the altered TEP and J I observed in the non-regenerative refractory period. Short-term application of hydrogen peroxide (H 2 O 2 ) rescues (from depleted ROS) and induces (from the refractory period) regeneration, TEP increase and J I reversal. H 2 O 2 is therefore necessary for and sufficient to induce regeneration and to regulate TEP and J I Epistasis assays show that voltage-gated Na + channels act downstream of H 2 O 2 to modulate regeneration. Altogether, these results suggest a novel mechanism for regeneration via redox-bioelectric orchestration. © 2016. Published by The Company of Biologists Ltd.
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Refractory Pain Management in Amyloid-Associated Peripheral Neuropathy.
Warner, Nafisseh S; Watson, James C; Bendel, Markus A; Moeschler, Susan M
2018-05-01
Systemic amyloidosis is a disease that often involves multiple organ systems, including the peripheral nervous system. Patients may present with severe, refractory neuropathic pain; however, the optimal treatment approach for pain for these patients remains unclear. A man with severe, refractory neuropathic pain in his bilateral upper and lower extremities and the trunk secondary to amyloid neuropathy is presented. Multiple medication trials, including neuropathic and opioid agents, produced considerable adverse effects and minimal relief. Scrambler therapy, a novel electrical stimulation modality, was used and was associated with substantial short-term but nonsustained benefit. Spinal cord stimulation was considered, but given his diffuse symptoms, it was deemed a less-than-optimal approach. Ultimately, an intrathecal drug delivery system was placed with infusion of hydromorphone, resulting in substantial pain reduction in all involved areas and with an improved adverse effect profile. This intervention resulted in immense improvement in the patient's quality of life, despite progression of his systemic amyloidosis. Severe pain in the setting of amyloid neuropathy is often difficult to treat. To our knowledge, this represents the first report of Scrambler therapy or an implanted intrathecal drug delivery system used for a patient with refractory amyloidosis-related neuropathic pain, resulting in substantial analgesic benefit and improved quality of life.
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Nanostructured refractory thin films for solar applications
NASA Astrophysics Data System (ADS)
Ollier, E.; Dunoyer, N.; Dellea, O.; Szambolics, H.
2014-08-01
Selective solar absorbers are key elements of all solar thermal systems. Solar thermal panels and Concentrated Solar Power (CSP) systems aim respectively at producing heat and electricity. In both cases, a surface receives the solar radiation and is designed to have the highest optical absorption (lowest optical reflectivity) of the solar radiation in the visible wavelength range where the solar intensity is the highest. It also has a low emissivity in the infrared (IR) range in order to avoid radiative thermal losses. Current solutions in the state of the art usually consist in deposited interferential thin films or in cermets [1]. Structured surfaces have been proposed and have been simulated because they are supposed to be more efficient when the solar radiation is not normal to the receiving surface and because they could potentially be fabricated with refractory materials able to sustain high operating temperatures. This work presents a new method to fabricate micro/nanostructured surfaces on molybdenum (refractory metal with a melting temperature of 2623°C). This method now allows obtaining a refractory selective surface with an excellent optical selectivity and a very high absorption in the visible range. This high absorption performance was obtained by achieving a double structuration at micro and nano scales thanks to an innovative process flow.
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Preliminary SP-100/Stirling Heat Exchanger Designs
NASA Astrophysics Data System (ADS)
Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brain; Dunn, Pat
1994-07-01
Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor(SSPC)was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.
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Preliminary SP-100/Stirling heat exchanger designs
NASA Astrophysics Data System (ADS)
Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat
1993-12-01
Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.
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Neurophysiological aspects of peripheral neuropathies.
MacKenzie, R A; Skuse, N F; Lethlean, A K
1976-01-01
1. Eighty-eight intrafascicular neural recordings were obtained in 10 normal subjects, 5 patients with axonal degeneration and 11 patients with demyelinating neuropathy. 2. Stimulus levels required for perception and fibre activation were higher in neuropathic subjects. Fibres transmitting touch perception had significantly lower conduction velocities in both patient groups, but were very much lower in the group with demyelinating neuropahty than the group with axonal degeneration. Maximum electrical stimulation evoked dispersed fibre responses in the axonal degeneration group and more dispersed, slowly conducting fibre potentials in the demyelinating group. In patients with hypertrophic Charcot-Marie-Tooth disorder, usually only a small group of slowly conducting low amplitude potentials was recorded. 3. Delivery of a train of supramaximal stimuli caused prolongation of latency and dispersion of fibre potentials in all microneurographic recordings. The changes were significantly greater in the axonal neuropathy group than in normals, and recovery was slower. The demyelinating neuropathies showed significantly greater changes than both the normal and the axonal neuropathy groups, and post-tetanic conduction slowing became even more marked after limb temperature was raised. 4. Surface SAP recordings showed normal refractory period in chronic axonal neuropathy but significant latency prolongation occurred in demyelinating neuropathy. 5. It is concluded that both receptor and nerve fibre abnormalities contribute to sensory dysfunction in degenerative and demyelinating neuropathies.
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Preliminary SP-100/Stirling heat exchanger designs
NASA Technical Reports Server (NTRS)
Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat
1993-01-01
Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Sabolsky, Edward M.; Bhattacharyya, Debangsu; Graham, David
The objective of the work was to develop refractory “smart bricks”, which would contain embedded temperature, strain/stress, and spallation sensors throughout the volume of high-chromia (-Cr2O3) refractory brick. The proposed work included work to interconnect the sensors to the reactor exterior, where the sensor signals may be processed by low-power electronics and transmitted wirelessly to a central processing hub. The data processing and wireless transmitter hardware was specifically designed to be isolated (with low power consumption) and to be adaptable to future implementation of energy-harvesting strategies for extended life. Finally, the collected data was incorporated into a model to estimatemore » refractory degradation, a technique that could help monitor the health of the refractory in real-time. The long-term goal of this program was to demonstrate high-temperature, wireless sensor arrays for in situ three-dimensional (3-D) refractory monitoring or mapping for slagging gasification systems. The research was in collaboration with HarbisonWalker International (HWI) Technology Center in West Mifflin, PA. HWI is a leading developer and manufacturer of ceramic refractory products for high-temperature applications. The work completed focused on the following areas: 1) Investigation of the chemical stability, microstructural evolution, grain growth kinetics, degree of homogeneity (quantitative image analysis), and electrical properties of refractory oxide-silicide composites at temperatures between 750-1450ºC; 2) Fabrication of silicide-alumina composite and oxide thermocouples and thermistor preforms and the development of techniques to embed them into high-chromia refractory bricks to form “smart bricks”; 3) Utilization of commercial off-the-shelf discrete components to prototype circuits for interfacing between smart brick sensors and the wireless sensor network. The prototypes were then used to design an integrated circuit for thermistor, thermocouple, and capacitive-based smart brick sensor interfacing; 4) Interfacing of the smart bricks with embedded sensors with wireless motes thus yielding a complete signal chain. This end-to-end data collection system was tested on a furnace heated to 1350 °C; 5) Development of a slag penetration model and a nonlinear unknown input filter for the data from the embedded sensors for estimating temperature and extent of slag penetration.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Martin, P.C.; DePoorter, G.L.; Munoz, D.R.
1991-02-01
We have initiated a three phase investigation of the development of high performance refractory fibers with enhanced insulating properties and longer usable lifetimes. This report presents the results of the first phase of the study, performed from Aug. 1989 through Feb. 1991, which shows that significant energy saving are possible through the use of high temperature insulating fibers that better retain their efficient insulating properties during the service lifetime of the fibers. The remaining phases of this program include the pilot scale development and then full scale production feasibility development and evaluation of enhanced high temperature refractory insulting fibers. Thismore » first proof of principle phase of the program presents a summary of the current use patterns of refractory fibers, a laboratory evaluation of the high temperature performance characteristics of selected typical refractory fibers and an analysis of the potential energy savings through the use of enhanced refractory fibers. The current use patterns of refractory fibers span a wide range of industries and high temperature furnaces within those industries. The majority of high temperature fiber applications are in furnaces operating between 2000 and 26000{degrees}F. The fibers used in furnaces operating within this range provide attractive thermal resistance and low thermal storage at reasonable cost. A series of heat treatment studies performed for this phase of the program has shown that the refractory fibers, as initially manufactured, have attractive thermal conductivities for high temperature applications but the fibers go through rapid devitrification and subsequent crystal growth upon high temperature exposure. Development of improved fibers, maintaining the favorable characteristics of the existing as-manufactured fibers, could save between 1 and 4% of the energy consumed in high temperature furnaces using refractory fibers.« less
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Cermet-fueled reactors for advanced space applications
DOE Office of Scientific and Technical Information (OSTI.GOV)
Cowan, C.L.; Palmer, R.S.; Taylor, I.N.
Cermet-fueled nuclear reactors are attractive candidates for high-performance advanced space power systems. The cermet consists of a hexagonal matrix of a refractory metal and a ceramic fuel, with multiple tubular flow channels. The high performance characteristics of the fuel matrix come from its high strength at elevated temperatures and its high thermal conductivity. The cermet fuel concept evolved in the 1960s with the objective of developing a reactor design that could be used for a wide range of mobile power generating sytems, including both Brayton and Rankine power conversion cycles. High temperature thermal cycling tests for the cermet fuel weremore » carried out by General Electric as part of the 710 Project (General Electric 1966), and by Argonne National Laboratory in the Direct Nuclear Rocket Program (1965). Development programs for cermet fuel are currently under way at Argonne National Laboratory and Pacific Northwest Laboratory. The high temperature qualification tests from the 1960s have provided a base for the incorporation of cermet fuel in advanced space applications. The status of the cermet fuel development activities and descriptions of the key features of the cermet-fueled reactor design are summarized in this paper.« less
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Computer simulation of fibrillation threshold measurements and electrophysiologic testing procedures
NASA Technical Reports Server (NTRS)
Grumbach, M. P.; Saxberg, B. E.; Cohen, R. J.
1987-01-01
A finite element model of cardiac conduction was used to simulate two experimental protocols: 1) fibrillation threshold measurements and 2) clinical electrophysiologic (EP) testing procedures. The model consisted of a cylindrical lattice whose properties were determined by four parameters: element length, conduction velocity, mean refractory period, and standard deviation of refractory periods. Different stimulation patterns were applied to the lattice under a given set of lattice parameter values and the response of the model was observed through a simulated electrocardiogram. The studies confirm that the model can account for observations made in experimental fibrillation threshold measurements and in clinical EP testing protocols.
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Bright and durable field emission source derived from refractory taylor cones
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hirsch, Gregory
A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tipmore » end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.« less
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Teruya, Alan T [Livermore, CA; Elmer,; John, W [Danville, CA; Palmer, Todd A [State College, PA
2011-03-08
A diagnostic system for characterization of an electron beam or an ion beam includes an electrical conducting disk of refractory material having a circumference, a center, and a Faraday cup assembly positioned to receive the electron beam or ion beam. At least one slit in the disk provides diagnostic characterization of the electron beam or ion beam. The at least one slit is located between the circumference and the center of the disk and includes a radial portion that is in radial alignment with the center and a portion that deviates from radial alignment with the center. The electron beam or ion beam is directed onto the disk and translated to the at least one slit wherein the electron beam or ion beam enters the at least one slit for providing diagnostic characterization of the electron beam or ion beam.
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Rosa, Regis Goulart; Rutzen, William; Madeira, Laura; Ascoli, Aline Maria; Dexheimer Neto, Felippe Leopoldo; Maccari, Juçara Gasparetto; de Oliveira, Roselaine Pinheiro; Teixeira, Cassiano
2015-01-01
Thoracic electrical impedance tomography is a real-time, noninvasive monitoring tool of the regional pulmonary ventilation distribution. Its bedside use in patients with acute respiratory distress syndrome has the potential to aid in alveolar recruitment maneuvers, which are often necessary in cases of refractory hypoxemia. In this case report, we describe the monitoring results and interpretation of thoracic electrical impedance tomography used during alveolar recruitment maneuvers in a patient with acute respiratory distress syndrome, with transient application of high alveolar pressures and optimal positive end-expiratory pressure titration. Furthermore, we provide a brief literature review regarding the use of alveolar recruitment maneuvers and monitoring using thoracic electrical impedance tomography in patients with acute respiratory distress syndrome. PMID:26761481
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Broseus, Julien; Florensa, Lourdes; Zipperer, Esther; Schnittger, Susanne; Malcovati, Luca; Richebourg, Steven; Lippert, Eric; Cermak, Jaroslav; Evans, Jyoti; Mounier, Morgane; Raya, José Maria; Bailly, François; Gattermann, Norbert; Haferlach, Torsten; Garand, Richard; Allou, Kaoutar; Besses, Carlos; Germing, Ulrich; Haferlach, Claudia; Travaglino, Erica; Luno, Elisa; Pinan, Maria Angeles; Arenillas, Leonor; Rozman, Maria; Perez Sirvent, Maria Luz; Favre, Bernardine; Guy, Julien; Alonso, Esther; Ahwij, Nuhri; Jerez, Andrés; Hermouet, Sylvie; Maynadié, Marc; Cazzola, Mario; Girodon, François
2012-01-01
Background Refractory anemia with ring sideroblasts associated with marked thrombocytosis was proposed as a provisional entity in the 2001 World Health Organization classification of myeloid neoplasms and also in the 2008 version, but its existence as a single entity is contested. We wish to define the clinical features of this rare myelodysplastic/myeloproliferative neoplasm and to compare its clinical outcome with that of refractory anemia with ring sideroblasts and essential thrombocythemia. Design and Methods We conducted a collaborative retrospective study across Europe. Our database included 200 patients diagnosed with refractory anemia with ring sideroblasts and marked thrombocytosis. For each of these patients, each patient diagnosed with refractory anemia with ring sideroblasts was matched for age and sex. At the same time, a cohort of 454 patients with essential thrombocythemia was used to compare outcomes of the two diseases. Results In patients with refractory anemia with ring sideroblasts and marked thrombocytosis, depending on the Janus Kinase 2 V617F mutational status (positive or negative) or platelet threshold (over or below 600×109/L), no difference in survival was noted. However, these patients had shorter overall survival and leukemia-free survival with a lower risk of thrombotic complications than did patients with essential thrombocythemia (P<0.001) but better survival (P<0.001) and a higher risk of thrombosis (P=0.039) than patients with refractory anemia with ring sideroblasts. Conclusions The clinical course of refractory anemia with ring sideroblasts and marked thrombocytosis is better than that of refractory anemia with ring sideroblasts and worse than that of essential thrombocythemia. The higher risk of thrombotic events in this disorder suggests that anti-platelet therapy might be considered in this subset of patients. From a clinical point of view, it appears to be important to consider refractory anemia with ring sideroblasts and marked thrombocytosis as a distinct entity. PMID:22532522
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DOE Office of Scientific and Technical Information (OSTI.GOV)
EWSUK,KEVIN G.
1999-11-24
Ceramics represent a unique class of materials that are distinguished from common metals and plastics by their: (1) high hardness, stiffness, and good wear properties (i.e., abrasion resistance); (2) ability to withstand high temperatures (i.e., refractoriness); (3) chemical durability; and (4) electrical properties that allow them to be electrical insulators, semiconductors, or ionic conductors. Ceramics can be broken down into two general categories, traditional and advanced ceramics. Traditional ceramics include common household products such as clay pots, tiles, pipe, and bricks, porcelain china, sinks, and electrical insulators, and thermally insulating refractory bricks for ovens and fireplaces. Advanced ceramics, also referredmore » to as ''high-tech'' ceramics, include products such as spark plug bodies, piston rings, catalyst supports, and water pump seals for automobiles, thermally insulating tiles for the space shuttle, sodium vapor lamp tubes in streetlights, and the capacitors, resistors, transducers, and varistors in the solid-state electronics we use daily. The major differences between traditional and advanced ceramics are in the processing tolerances and cost. Traditional ceramics are manufactured with inexpensive raw materials, are relatively tolerant of minor process deviations, and are relatively inexpensive. Advanced ceramics are typically made with more refined raw materials and processing to optimize a given property or combination of properties (e.g., mechanical, electrical, dielectric, optical, thermal, physical, and/or magnetic) for a given application. Advanced ceramics generally have improved performance and reliability over traditional ceramics, but are typically more expensive. Additionally, advanced ceramics are typically more sensitive to the chemical and physical defects present in the starting raw materials, or those that are introduced during manufacturing.« less
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Corrosion resistance of ceramic refractories to simulated waste glasses at high temperature
DOE Office of Scientific and Technical Information (OSTI.GOV)
Xing, S.B.; Lin, Y.; Mohr, R.K.
1996-08-01
In many vitrification processes, refractory materials are used to contain the waste glass melt. The corrosive nature of the high-temperature melt consumes the waste feed materials but also limits refractory life. As vitrification is applied to more diverse waste streams, and particularly in higher-temperature applications, increasingly severe demands are placed on the refractory materials. A variety of potential refractory materials including Fused-cast AZS, Monofrax K3, Monofrax E, and the Corhart refractories ER1195, ER2161, C1215, C1215Z, Rechrome, and T1186, were subjected to corrosion testing at 1,450 C using the ASTM C-621 procedure. A series of simulated waste glasses was used whichmore » included F, Cl, S, Cu, Zn, Pb; these minor components were found to cause significant, and in some cases drastic, increases in corrosion rates. The corrosion tests were conducted over a range of time intervals extending to 144 hrs in order to investigate the kinetics of the corrosion processes. The change of the concentrations of constituents in the glass was monitored by compositional analysis of glass samples and correlated to the observed extent of corrosion; typically, components of the material under test increase with time while key minor components, such as Co and Pb, decrease. The rate of corrosion of high-zirconia refractories was slowed considerably by adding zirconia to the waste glass composition; this has the added benefit of improving the aqueous leach resistance of the waste form that is produced.« less
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Gonzales, Matthew J.; Vincent, Kevin P.; Rappel, Wouter-Jan; Narayan, Sanjiv M.; McCulloch, Andrew D.
2014-01-01
Aims The aim of this study was to investigate structural contributions to the maintenance of rotors in human atrial fibrillation (AF) and possible mechanisms of termination. Methods and results A three-dimensional human biatrial finite element model based on patient-derived computed tomography and arrhythmia observed at electrophysiology study was used to study AF. With normal physiological electrical conductivity and effective refractory periods (ERPs), wave break failed to sustain reentrant activity or electrical rotors. With depressed excitability, decreased conduction anisotropy, and shorter ERP characteristic of AF, reentrant rotors were readily maintained. Rotors were transiently or permanently trapped by fibre discontinuities on the lateral wall of the right atrium near the tricuspid valve orifice and adjacent to the crista terminalis, both known sites of right atrial arrhythmias. Modelling inexcitable regions near the rotor tip to simulate fibrosis anchored the rotors, converting the arrhythmia to macro-reentry. Accordingly, increasing the spatial core of inexcitable tissue decreased the frequency of rotation, widened the excitable gap, and enabled an external wave to impinge on the rotor core and displace the source. Conclusion These model findings highlight the importance of structural features in rotor dynamics and suggest that regions of fibrosis may anchor fibrillatory rotors. Increasing extent of fibrosis and scar may eventually convert fibrillation to excitable gap reentry. Such macro-reentry can then be eliminated by extending the obstacle or by external stimuli that penetrate the excitable gap. PMID:25362167
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Cosio, F G; Palacios, J; Vidal, J M; Cocina, E G; Gómez-Sánchez, M A; Tamargo, L
1983-01-01
Extrastimulus-induced intraatrial conduction delays were measured in 12 patients with documented episodes of atrial fibrillation (AF) by recording atrial electrograms at the high right atrium, His bundle region, and coronary sinus. Seventeen patients with and without heart disease, but without atrial arrhythmias served as the control group. During baseline-paced atrial rhythms, a conduction delay zone could be delineated, near the atrial effective refractory period, during which all extrastimuli produced conduction delays. When compared at the same paced cycle lengths (500 to 650 ms), the patients with AF had shorter atrial effective refractory periods (mean +/- standard deviation 206 +/- 24.1 versus 233 +/- 28.2 in control patients, p less than 0.02), wider conduction delay zones (79 +/- 21.7 ms versus 52 +/- 21 in control patients, p less than 0.01), and longer conduction delays both to the His bundle region (64 +/- 18.3 ms versus 35 +/- 21.7 in control patients, p less than 0.005) and the coronary sinus (76 +/- 18.9 ms versus 35 +/- 16.1 in control patients, p less than 0.001). Repetitive atrial responses were recorded in 6 patients with AF and in 9 control subjects. Sinus nodal function abnormalities were detected in 6 of the patients with fibrillation. Patients with AF had a higher tendency than control subjects to develop slow intraatrial conduction, as well as shorter effective refractory periods. Since both features would favor reentry, they may be the electrophysiologic manifestations of the abnormalities making these patients prone to atrial reentrant arrhythmias. Repetitive atrial responses were of no predictive value. Sinus nodal dysfunction was frequently found, but was not essential for the occurrence of AF.
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Jessurun, G A; Hautvast, R W; DeJongste, M J; Meyler, W J; van Boven AJ; Crijns, H J
1999-07-01
Patients with symptomatic small vessel coronary artery disease may be inadequate candidates for revascularization procedures. They may suffer from refractory angina, which does not respond to maximal anti-anginal drug therapy. In addition to patients with end stage coronary artery disease and syndrome X, this newly defined group of subjects with an isolated stenosis of a small coronary artery may benefit from electrical neurostimulation. We describe two patients with intractable angina caused by a significant narrowing of a diagonal branch. This treatment modality should be considered as an alternative method for unsatisfactory revascularization procedures.
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NASA Technical Reports Server (NTRS)
Fuller, R. A.; Schnacke, A. W.
1974-01-01
An electromagnetic pump, in which pressure is developed in mercury because of the interaction of the magnetic field and current which flows as a result of the voltage induced in the mercury contained in the pump duct, was developed for the SNAP-8 refractory boiler test facility. Pump performance results are presented for ten duct configurations and two stator sizes. These test results were used to design and fabricate a pump which met the SNAP-8 criteria of 530 psi developed pressure at 12,500 lb/hr. The pump operated continuously for over 13,000 hours without failure or performance degradation. Included in this report are descriptions of the experimental equipment, measurement techniques, all experimental data, and an analysis of the electrical losses in the pump.
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The cathode material for a plasma-arc heater
NASA Astrophysics Data System (ADS)
Yelyutin, A. V.; Berlin, I. K.; Averyanov, V. V.; Kadyshevskii, V. S.; Savchenko, A. A.; Putintseva, R. G.
1983-11-01
The cathode of a plasma arc heater experiences a large thermal load. The temperature of its working surface, which is in contact with the plasma, reaches high values, as a result of which the electrode material is subject to erosion. Refractory metals are usually employed for the cathode material, but because of the severe erosion do not usually have a long working life. The most important electrophysical characteristic of the electrode is the electron work function. The use of materials with a low electron work function allows a decrease in the heat flow to the cathode, and this leads to an increase in its erosion resistance and working life. The electroerosion of certain materials employed for the cathode in an electric arc plasma generator in the process of reduction smelting of refractory metals was studied.
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Cao, Xian; Yu, Chunyan; Wang, Hui; Zhou, Fang; Li, Xianning
2017-04-01
In this study, the soil microbial fuel cells (MFCs) were constructed based on sandy soil to remove the refractory organic pesticide hexachlorobenzene (HCB) in topsoil by a simple method. The construction of membraneless single-chamber soil MFCs by setting up the cathode- and the anode-activated carbon, inoculating the sludge and adding the co-substrates can promote HCB removal significantly. The results showed that HCB removal efficiencies in the soils contaminated with 40, 80 and 200 mg/kg were 71.14%, 62.15% and 50.06%, respectively, which were 18.65%, 18.46% and 19.17% higher than the control, respectively. The electricity generation of soil MFCs in different HCB concentrations was analyzed. The highest power density reached was 70.8 mW/m 2 , and an internal resistance of approximately 960 Ω was obtained when an external resistance loading of 1000 Ω was connected. Meanwhile, the influences of temperature, substrate species and substrate concentrations on soil MFCs initial electricity production were investigated. The addition of the anionic surfactant sodium dodecyl sulfate (SDS) into the soil MFCs system contributed to the improvement in HCB removal efficiency.
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Distributed Fiber Optic Sensor for On-Line Monitoring of Coal Gasifier Refractory Health
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Anbo; Yu, Zhihao
This report summarizes technical progress on the program “Distributed Fiber Optic Sensor for On-Line Monitoring of Coal Gasifier Refractory Health,” funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The scope of work entails analyses of traveling grating generation technologies in an optical fiber, as well as the interrogation of the gratings to infer a distributed temperature along the fiber, for the purpose of developing a real-time refractory health condition monitoring technology for coal gasifiers. Duringmore » the project period, which is from 2011-2015, three different sensing principles were studied, including four-wave mixing (FWM), coherent optical time-domain reflectometer (C-OTDR) and Brillouin optical time-domain analysis (BOTDA). By comparing the three methods, the BOTDA was selected for further development into a complete bench-top sensing system for the proposed high-temperature sensing application. Based on the input from Eastman Chemical, the industrial collaborator on this project, a cylindrical furnace was designed and constructed to simulate typical gasifier refractory temperature conditions in the laboratory, and verify the sensor’s capability to fully monitor refractory conditions on the back-side at temperatures up to 1000°C. In the later stages of the project, the sensing system was tested in the simulated environment for its sensing performance and high-temperature survivability. Through theoretical analyses and experimental research on the different factors affecting the sensor performance, a sensor field deployment strategy was proposed for possible future sensor field implementations.« less
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Töllner, Kathrin; Brandt, Claudia; Erker, Thomas; Löscher, Wolfgang
2015-01-05
In about 20-40% of patients, status epilepticus (SE) is refractory to standard treatment with benzodiazepines, necessitating second- and third-line treatments that are not always successful, resulting in increased mortality. Rat models of refractory SE are instrumental in studying the changes underlying refractoriness and to develop more effective treatments for this severe medical emergency. Failure of GABAergic inhibition is a likely cause of the development of benzodiazepine resistance during SE. In addition to changes in GABAA receptor expression, trafficking, and function, alterations in Cl(-) homeostasis with increased intraneuronal Cl(-) levels may be involved. Bumetanide, which reduces intraneuronal Cl(-) by inhibiting the Cl(-) intruding Na(+), K(+), Cl(-) cotransporter NKCC1, has been reported to interrupt SE induced by kainate in urethane-anesthetized rats, indicating that this diuretic drug may be an interesting candidate for treatment of refractory SE. In this study, we evaluated the effects of bumetanide in the kainate and lithium-pilocarpine models of SE as well as a model in which SE is induced by sustained electrical stimulation of the basolateral amygdala. Unexpectedly, bumetanide alone was ineffective to terminate SE in both conscious and anesthetized adult rats. However, it potentiated the anticonvulsant effect of low doses of phenobarbital, although this was only seen in part of the animals; higher doses of phenobarbital, particularly in combination with diazepam, were more effective to terminate SE than bumetanide/phenobarbital combinations. These data do not suggest that bumetanide, alone or in combination with phenobarbital, is a valuable option in the treatment of refractory SE in adult patients. Copyright © 2014 Elsevier B.V. All rights reserved.
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Metal alloy coatings and methods for applying
Merz, Martin D.; Knoll, Robert W.
1991-01-01
A method of coating a substrate comprises plasma spraying a prealloyed feed powder onto a substrate, where the prealloyed feed powder comprises a significant amount of an alloy of stainless steel and at least one refractory element selected from the group consisting of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The plasma spraying of such a feed powder is conducted in an oxygen containing atmosphere and forms an adherent, corrosion resistant, and substantially homogenous metallic refractory alloy coating on the substrate.
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Modelling Simulation and Comparison of Refractory Corrosion at RHI's Technology Center
NASA Astrophysics Data System (ADS)
Gregurek, Dean; Ressler, Angelika; Franzkowiak, Anna; Spanring, Alfred
In order to determine the most suitable refractory products and improve the lining lifetime for the diverse furnaces used in the nonferrous metal industry, corrosion tests are performed at RHF's Technology Center. The practical facilities include the cup test, induction furnace, rotary kiln, and drip slag test described in this paper, which enable a comprehensive understanding of the chemo-thermal brick wear on a pilot scale. The corrosion trials are performed with actual slags generated during operations at a customer's plant. To determine the highest influencing wear parameter, every single test is combined with a detailed mineralogical investigation and thermochemical calculations performed using FactSage. Based on the results, tailored refractory solutions for the nonferrous metal industry can be provided in combination with trials conducted at the customer's site.
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Improvements in Ionized Cluster-Beam Deposition
NASA Technical Reports Server (NTRS)
Fitzgerald, D. J.; Compton, L. E.; Pawlik, E. V.
1986-01-01
Lower temperatures result in higher purity and fewer equipment problems. In cluster-beam deposition, clusters of atoms formed by adiabatic expansion nozzle and with proper nozzle design, expanding vapor cools sufficiently to become supersaturated and form clusters of material deposited. Clusters are ionized and accelerated in electric field and then impacted on substrate where films form. Improved cluster-beam technique useful for deposition of refractory metals.
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Washizuka, Takashi; Chinushi, Masaomi; Watanabe, Hiroshi; Hosaka, Yukio; Komura, Satoru; Sugiura, Hirotaka; Hirono, Takashi; Furushima, Hiroshi; Tanabe, Yasutaka; Aizawa, Yoshifusa
2005-12-01
Some patients with an implantable cardioverter-defibrillator (ICD) suffer from burst of inappropriate multiple discharges (severe electrical storm), and because the current therapeutic options are limited, the effect of nifekalant hydrochloride, a new class III drug, on severe electrical storm was investigated in the present study. Ninety-one consecutive patients treated with ICD were included in the study (M 70; mean age 58 years; left ventricular ejection fraction 45+/-15%). Severe electrical storm was defined as more than 10 ICD discharges within 1 h. During a mean follow-up period of 30+/-13 months, 41/91 (45%) patients had appropriate ICD therapy for arrhythmias and severe electrical storm occurred in 11 of them (12%) at 20+/-18 months after ICD implantation. The mean number of ICD discharges/h during severe electrical storm was 18+/-12. In 4 of 10 patients, severe electrical storm was successfully suppressed by a combination of deep sedation and beta-blocking agent; 6 other patients were refractory to this treatment, but severe electrical storm was successfully suppressed by intravenous administration of nifekalant hydrochloride with no adverse effects. Nifekalant hydrochloride is an effective and safe treatment for severe electrical storm.
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Illness identity in young adults with refractory epilepsy.
Luyckx, Koen; Oris, Leen; Raymaekers, Koen; Rassart, Jessica; Moons, Philip; Verdyck, Ludo; Mijnster, Teus; Mark, Ruth E
2018-03-01
Refractory epilepsy is an intrusive condition with important implications for daily functioning in emerging and young adulthood. The present study examined the degree to which refractory epilepsy is integrated in one's identity, and examined how such a sense of illness identity was related to health-related quality of life (HRQOL). A total of 121 18- to 40-year-old patients with refractory epilepsy (56.2% women) completed self-report questionnaires assessing the four illness identity states of acceptance, enrichment, engulfment, and rejection (Illness Identity Questionnaire (IIQ)); HRQOL (Quality of Life in Epilepsy Inventory - 31); and seizure frequency and severity (Liverpool Seizure Severity Scale (LSSS)). Illness identity scores were compared with a sample of 191 patients with a nonneurological chronic disease (congenital heart disease). Hierarchical regression analyses were conducted to assess the predictive value of illness identity for HRQOL when simultaneously controlling for demographic and clinical features. Patients with refractory epilepsy scored higher on rejection and engulfment and lower on acceptance when compared with patients with congenital heart disease. Further, seizure severity and number of medication side-effects were positively related to engulfment and negatively to acceptance. Finally, when simultaneously controlling for various demographic and clinical variables, illness identity significantly predicted HRQOL (with engulfment being the strongest and most consistent predictor). The extent to which patients with refractory epilepsy succeed in integrating their illness into their identity may have important implications for HRQOL. Clinicians should be especially attentive for signs that patients feel engulfed by their epilepsy. Copyright © 2018 Elsevier Inc. All rights reserved.
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NASA Technical Reports Server (NTRS)
Goldsby, Jon C.
2003-01-01
Lanthanum titanate (La2Ti2O7) a layered distorted perovskite (1) with space group Pna2(sub 1) has been shown to have potential as a high temperature piezoelectric (2). However this highly refractory oxide compound must be consolidated at relatively high temperatures approximately 1400 C. Commercial La2Ti207 powders were mechanically alloyed with additions of Y2O3 to lower the consolidation temperature by 300 C and to provide post processing mechanical stability. Temperature dependent electrical, elastic and anelastic behavior were selected as nondestructive means of evaluating the effects of yttria on the properties of this ferroceramic material.
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NASA Astrophysics Data System (ADS)
Adabifiroozjaei, Esmaeil; Saidi, Ali; Monshi, Ahmad; Koshy, Pramod
2011-04-01
Andalusite containing low-cement castables (LCCs) have been used in aluminum casthouses for several decades. CaF2 is commonly added to the refractory to improve its corrosion resistance mainly because of its role in the formation of anorthite (CaAl2Si2O8); the latter has been reported to decrease the penetration of molten aluminum alloys into refractories. This article investigates the effect of the addition of different calcium containing compounds (CaO, CaCO3, CaSO4, CaF2, Clinker white cement, calcia feldspar, wollastonite, and Ca3(PO4)2) on reactions with the refractory constituents to form anorthite as well as the effect of the additives on both the subsequent physical properties and the corrosion resistance of andalusite LCC refractories. Corrosion tests using the Alcoa cup test at temperatures (1123 K [850 °C] for 150 hours and 1433 K [1160 °C] for 72 hours) were conducted to determine the extent of penetration, whereas immersion tests in boiling water were conducted to determine the extent of open porosity in the material. Scanning electron microscopy coupled with energy dispersive spectrometer, optical microscopy, and X-ray diffraction techniques were employed to characterize the phase formations in the materials after the tests. The study demonstrated that both calcia feldspar and clinker white cement had the potential to be used as new additives for decreasing the penetration of molten Al-alloy into the refractory materials. Anorthite formation (in the refractory matrix), along with the absence of glassy phases, were responsible for the improvement in the corrosion resistance of the castables containing calcia feldspar. However, in the sample containing cement, the presence of calcium silicate phases were observed to resist reactions with molten aluminum. The observed results were validated using thermodynamic calculations, which indicated that tricalcium silicates (3CaO.SiO2) and dicalcium silicate (2CaO.SiO2) phases were more resistant than wollastonite (CaSiO3) for applications involving contact with molten aluminum.
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Electrical Storm: Incidence, Prognosis and Therapy.
Sagone, Antonio
2015-12-01
The term "electrical storm" indicates a life-threatening clinical condition characterized by the recurrence of hemodynamically unstable ventricular tachycardia and/or ventricular fibrillation, in particular in patients with ICD implanted for primary or secondary prevention. Although there isn't a shared definition of electrical storm, nowadays the most accepted definition refers to three or more separate arrhythmia episodes leading to ICD therapies including antitachycardia pacing or shock occurring over a single 24 hours' time period. Clinical presentation can be dramatic and triggering mechanism are not clear at all yet, but electrical storm is associated with high mortality rates and low patients quality of life, both in the acute phase and in the long term. The first line therapy is based on antiarrhythmic drugs to suppress electrical storm, but in refractory patients, interventions such as catheter ablation or in some cases surgical cardiac sympathetic denervation might be helpful. Anyhow, earlier interventional management can lead to better outcomes than persisting with antiarrhythmic pharmacologic therapy and, when available, an early interventional approach should be preferred.
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Gonzales, Matthew J; Vincent, Kevin P; Rappel, Wouter-Jan; Narayan, Sanjiv M; McCulloch, Andrew D
2014-11-01
The aim of this study was to investigate structural contributions to the maintenance of rotors in human atrial fibrillation (AF) and possible mechanisms of termination. A three-dimensional human biatrial finite element model based on patient-derived computed tomography and arrhythmia observed at electrophysiology study was used to study AF. With normal physiological electrical conductivity and effective refractory periods (ERPs), wave break failed to sustain reentrant activity or electrical rotors. With depressed excitability, decreased conduction anisotropy, and shorter ERP characteristic of AF, reentrant rotors were readily maintained. Rotors were transiently or permanently trapped by fibre discontinuities on the lateral wall of the right atrium near the tricuspid valve orifice and adjacent to the crista terminalis, both known sites of right atrial arrhythmias. Modelling inexcitable regions near the rotor tip to simulate fibrosis anchored the rotors, converting the arrhythmia to macro-reentry. Accordingly, increasing the spatial core of inexcitable tissue decreased the frequency of rotation, widened the excitable gap, and enabled an external wave to impinge on the rotor core and displace the source. These model findings highlight the importance of structural features in rotor dynamics and suggest that regions of fibrosis may anchor fibrillatory rotors. Increasing extent of fibrosis and scar may eventually convert fibrillation to excitable gap reentry. Such macro-reentry can then be eliminated by extending the obstacle or by external stimuli that penetrate the excitable gap. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.
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Intravenous ketamine for subacute treatment of refractory chronic migraine: a case series.
Lauritsen, Clinton; Mazuera, Santiago; Lipton, Richard B; Ashina, Sait
2016-12-01
Refractory migraine is a challenging condition with great impact on health related quality of life. Intravenous (IV) ketamine has been previously used to treat various refractory pain conditions. We present a series of patients with refractory migraine treated with intravenous ketamine in the hospital setting. Based on retrospective chart review, we identified six patients with refractory migraine admitted from 2010 through 2014 for treatment with intravenous ketamine. Ketamine was administered using a standard protocol starting with a dose of 0.1 mg/kg/hr and increased by 0.1 mg/kg/hr every 3 to 4 h as tolerated until the target pain score of 3/10 was achieved and maintained for at least 8 h. Visual Analogue Scale (VAS) scores at time of hospital admission were obtained as well as average baseline VAS scores prior to ketamine infusion. A phone interview was conducted for follow-up of migraine response in the 3 to 6 months following ketamine infusion. The study sample had a median age of 36.5 years (range 29-54) and 83% were women. Pre-treatment pain scores ranged from 9 to 10. All patients achieved a target pain level of 3 or less for 8 h; the average ketamine infusion rate at target was 0.34 mg/kg/hour (range 0.12-0.42 mg/kg/hr). One patient reported a transient out-of-body hallucination following an increase in the infusion rate, which resolved after decreasing the rate. There were no other significant side effects. IV ketamine was safely administered in the hospital setting to patients with refractory chronic migraine. Treatment was associated with short term improvement in pain severity in 6 of 6 patients with refractory chronic migraine. Prospective placebo-controlled trials are needed to assess short term and long-term efficacy of IV ketamine in refractory chronic migraine.
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Moccia, Alden A; Hitz, Felicitas; Hoskins, Paul; Klasa, Richard; Power, Maryse M; Savage, Kerry J; Shenkier, Tamara; Shepherd, John D; Slack, Graham W; Song, Kevin W; Gascoyne, Randy D; Connors, Joseph M; Sehn, Laurie H
2017-02-01
The optimal choice of salvage therapy for patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) or Hodgkin lymphoma (HL) remains unknown. Based on promising results of phase II trials, the preferred salvage regimen in British Columbia since 2002 has been the out-patient regimen, gemcitabine, dexamethasone, and cisplatin (GDP). We conducted a retrospective analysis including all patients with relapsed/refractory DLBCL or HL who received GDP as salvage therapy between September 2002 and June 2010. We identified 235 patients: 152 DLBCL, 83 HL. Overall response rates were 49% and 71% for patients with DLBCL and HL, respectively. Within the transplant-eligible population, 52% of patients with DLBCL and 96% of patients with HL proceeded to stem cell transplantation. The 2-year progression-free survival and overall survival were 21% and 28% in the DLBCL cohort, and 58% and 85% in the HL group. GDP is an effective and well-tolerated out-patient salvage regimen for relapsed/refractory DLBCL and HL.
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The composition and origin of the moon
NASA Technical Reports Server (NTRS)
Anderson, D. L.
1972-01-01
A model is presented of the moon as a high temperature condensate from the solar nebula. The Ca, Al, and Ti rich compounds condense first in a cooling nebula. The initial high temperature mineralogy is gehlenite, spinel, perovskite, Ca-Al-rich pyroxenes, and anorthite. Type 3 carbonaceous chondrites such as the Allende meteorite are composed primarily of these minerals and are highly enriched in refractories. These inclusions can yield basalt and anorthosite in the proportions required to eliminate the europium anomaly, leaving a residual spinel-melilite interior. The inferred high U content of the lunar interior, both from the Allende analogy and the high heat flow, indicates a high temperature interior. The model is consistent with extensive early, shallow melting at 3 A.E., and with high deep internal temperatures. It is predicted that the outer 250 km is rich in plagioclase and FeO. The low iron content of the interior raises the interior temperatures estimated from electrical conductivity by some 800 C.
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Vagal nerve stimulator: Evolving trends
Ogbonnaya, Sunny; Kaliaperumal, Chandrasekaran
2013-01-01
Over three decades ago, it was found that intermittent electrical stimulation from the vagus nerve produces inhibition of neural processes, which can alter brain activity and terminate seizures. This paved way for the concept of vagal nerve stimulator (VNS). We describe the evolution of the VNS and its use in different fields of medicine. We also review the literature focusing on the mechanism of action of VNS producing desired effects in different conditions. PUBMED and EMBASE search was performed for ‘VNS’ and its use in refractory seizure management, depression, obesity, memory, and neurogenesis. VNS has been in vogue over for the past three decades and has proven to reduce the intensity and frequency of seizure by 50% in the management of refractory seizures. Apart from this, VNS has been shown to promote neurogenesis in the dentate gyrus of rat hippocampus after 48 hours of stimulation of the vagus nerve. Improvement has also been observed in non-psychotic major depression from a randomized trial conducted 7 years ago. The same concept has been utilized to alter behavior and cognition in rodents, and good improvement has been observed. Recent studies have proven that VNS is effective in obesity management in patients with depression. Several hypotheses have been postulated for the mechanism of action of VNS contributing to its success. VNS has gained significant popularity with promising results in epilepsy surgery and treatment-resistant depression. The spectrum of its use has also extended to other fields of medicine including obesity, memory, and neurogenesis, and there is still a viable scope for its utility in the future. PMID:23633829
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Place, Andrew E; Goldsmith, Kelly; Bourquin, Jean-Pierre; Loh, Mignon L; Gore, Lia; Morgenstern, Daniel A; Sanzgiri, Yeshwant; Hoffman, David; Zhou, Ying; Ross, Jeremy A; Prine, Betty; Shebley, Mohamad; McNamee, Megan; Farazi, Thalia; Kim, Su Young; Verdugo, Maria; Lash-Fleming, Leanne; Zwaan, C Michel; Vormoor, Josef
2018-03-29
Venetoclax is a highly selective, potent BCL-2 inhibitor that is approved for some patients previously treated for chronic lymphocytic leukemia, and has shown promising activity in adult studies across several hematologic malignancies. Preclinical studies have demonstrated venetoclax activity in pediatric patient-derived xenograft models and cell lines; however, clinical studies in pediatric patients have yet to be conducted. The prognosis is poor for children with most relapsed/refractory malignancies, and limited treatment options result in unmet clinical need. Herein, we describe the rationale and design of the first study of venetoclax in pediatric patients with relapsed/refractory malignancies: a Phase I trial investigating the safety and pharmacokinetics of venetoclax monotherapy followed by the addition of chemotherapy (Trial registration: EudraCT 2017-000439-14; NCT03236857).
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Transcutaneous sacral neurostimulation for irritative voiding dysfunction.
Walsh, I K; Johnston, R S; Keane, P F
1999-01-01
Patients with irritative voiding dysfunction are often unresponsive to standard clinical treatment. We evaluated the response of such individuals to transcutaneous electrical stimulation of the third sacral nerve. 32 patients with refractory irritative voiding dysfunction (31 female and 1 male; mean age 47 years) were recruited to the study. Ambulatory transcutaneous electrical neurostimulation was applied bilaterally to the third sacral dermatomes for 1 week. Symptoms of frequency, nocturia, urgency, and bladder pain were scored by each patient throughout and up to 6 months following treatment. The mean daytime frequency was reduced from 11.3 to 7.96 (p = 0.01). Nocturia episodes were reduced from a mean of 2.6 to 1.8 (p = 0.01). Urgency and bladder pain mean symptom scores were reduced from 5.97 to 4.89 and from 1.48 to 0.64, respectively. After stopping therapy, symptoms returned to pretreatment levels within 2 weeks in 40% of the patients and within 6 months in 100%. Three patients who continued with neurostimulation remained satisfied with this treatment modality at 6 months. Transcutaneous third sacral nerve stimulation may be an effective and noninvasive ambulatory technique for the treatment of patients with refractory irritative voiding dysfunction. Following an initial response, patients may successfully apply this treatment themselves to ensure long-term relief.
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Effect of Right Ventricular versus Biventricular Pacing on Electrical Remodeling in the Normal Heart
Saba, Samir; Mehdi, Haider; Mathier, Michael A.; Islam, M. Zahadul; Salama, Guy; London, Barry
2010-01-01
Background Biventricular (BIV) pacing can improve cardiac function in heart failure by altering the mechanical and electrical substrates. We investigated the effect of BIV versus right ventricular (RV) pacing on the normal heart. Methods and Results Male New Zealand White rabbits (n=33) were divided into 3 groups: sham-operated (control), RV pacing, and BIV pacing groups. Four weeks after surgery, the native QT (p=0.004) interval was significantly shorter in the BIV group compared to the RV or sham-operated groups. Also, compared to rabbits in the RV group, rabbits in the BIV group had shorter RV ventricular effective refractory period (VERP) at all cycle lengths, and shorter LV paced QT interval during the drive train of stimuli and close to refractoriness (p<0.001 for all comparisons). Protein expression of the KVLQT1 was significantly increased in the BIV group compared to the RV and control groups, while protein expression of SCN5A and connexin43 was significantly decreased in the RV compared to the other study groups. Erg protein expression was significantly increased in both pacing groups compared to the controls. Conclusions In this rabbit model, we demonstrate a direct effect of BIV but not RV pacing on shortening the native QT interval as well as the paced QT interval during burst pacing and close to the VERP. These findings underscore the fact that the effect of BIV pacing is partially mediated through direct electrical remodeling and may have implications as to the effect of BIV pacing on arrhythmia incidence and burden. PMID:20042767
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Kimura, Utako; Takeuchi, Kaori; Kinoshita, Ayako; Takamori, Kenji; Suga, Yasushi
2014-03-01
Common warts (verruca vulgaris) are the most commonly seen benign cutaneous tumors. However, warts in the hands and feet regions often respond poorly to treatment, some are resistant to more than 6 months of treatment with currently available modalities, including cryotherapy, being defined as refractory warts. We investigated the usefulness of long-pulsed neodymium:yttrium-aluminum-garnet (LP-Nd:YAG) treatment for refractory warts. The clinical trial was conducted on 20 subjects (11 male, nine female) with a total of 34 lesions (periungual/subungual areas, plantar areas, fingers and/or toes). All the subjects suffered from refractory warts despite conventional treatments for more than 6 months. The patients were administrated up to six sessions of treatment, at intervals of 4 weeks between sessions, with an LP-Nd:YAG at a spot size of 5 mm, pulse duration of 15 msec and fluence of 150-185 J/cm(2) . Evaluation of the treatment results at 24 weeks after the initial treatment showed complete clearance of the refractory warts in 56% of the patients. Histological evaluation showed separation of the dermis and epidermis at the basement membrane with coagulated necrosis of the wart tissue in the lower epidermis, as well as coagulation and destruction of the blood vessels in the papillary dermis following the laser irradiation. No scarring, post-hyperpigmentary changes or serious adverse events were documented. Our preliminary results show that LP-Nd:YAG treatments are safe and effective for refractory warts of hands and feet, causing minimal discomfort, and is a viable treatment alternative. © 2014 Japanese Dermatological Association.
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Rocker, Graeme; Young, Joanne; Donahue, Margaret; Farquhar, Morag; Simpson, Catherine
2012-01-01
Background: A recent national practice guideline recommends the use of opioids for the treatment of refractory dyspnea in patients with advanced chronic obstructive pulmonary disease (COPD). We conducted two qualitative studies to explore the experiences of patients and family caregivers with opioids for refractory COPD-related dyspnea and the perspectives and attitudes of physicians toward opioids in this context. Methods: Patients (n = 8; 5 men, 3 women), their caregivers (n = 12; 5 men, 7 women) and physicians (n = 28, 17 men, 11 women) in Nova Scotia participated in the studies. Semistructured interviews were recorded, transcribed verbatim, coded conceptually and analyzed for emergent themes using interpretive description methodology. Results: Patients reported that opioids provided a sense of calm and relief from severe dyspnea. Family caregivers felt that opioids helped patients to breathe more “normally,” observed improvements in patients’ symptoms of anxiety and depression, and experienced reductions in their own stress. Patients reported substantial improvements in their quality of life. All patients and family caregivers wanted opioid therapy to continue. Most physicians were reluctant to prescribe opioids for refractory dyspnea, describing a lack of related knowledge and experience, and fears related to the potential adverse effects and legal censure. Interpretation: Discrepancies between the positive experiences of patients and family caregivers with opioids and the reluctance of physicians to prescribe opioids for refractory dyspnea constitute an important gap in care. Bridging this gap will require initiatives to improve the uptake of practice guidelines and to increase confidence in prescribing opioids for dyspnea refractory to conventional treatment. PMID:22529167
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Rocker, Graeme; Young, Joanne; Donahue, Margaret; Farquhar, Morag; Simpson, Catherine
2012-06-12
A recent national practice guideline recommends the use of opioids for the treatment of refractory dyspnea in patients with advanced chronic obstructive pulmonary disease (COPD). We conducted two qualitative studies to explore the experiences of patients and family caregivers with opioids for refractory COPD-related dyspnea and the perspectives and attitudes of physicians toward opioids in this context. Patients (n = 8; 5 men, 3 women), their caregivers (n = 12; 5 men, 7 women) and physicians (n = 28, 17 men, 11 women) in Nova Scotia participated in the studies. Semistructured interviews were recorded, transcribed verbatim, coded conceptually and analyzed for emergent themes using interpretive description methodology. Patients reported that opioids provided a sense of calm and relief from severe dyspnea. Family caregivers felt that opioids helped patients to breathe more "normally," observed improvements in patients' symptoms of anxiety and depression, and experienced reductions in their own stress. Patients reported substantial improvements in their quality of life. All patients and family caregivers wanted opioid therapy to continue. Most physicians were reluctant to prescribe opioids for refractory dyspnea, describing a lack of related knowledge and experience, and fears related to the potential adverse effects and legal censure. Discrepancies between the positive experiences of patients and family caregivers with opioids and the reluctance of physicians to prescribe opioids for refractory dyspnea constitute an important gap in care. Bridging this gap will require initiatives to improve the uptake of practice guidelines and to increase confidence in prescribing opioids for dyspnea refractory to conventional treatment.
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Zhao, Yongdong; Wu, Eveline Y; Oliver, Melissa S; Cooper, Ashley M; Basiaga, Matthew L; Vora, Sheetal S; Lee, Tzielan C; Fox, Emily; Amarilyo, Gil; Stern, Sara M; Dvergsten, Jeffrey A; Haines, Kathleen A; Rouster-Stevens, Kelly A; Onel, Karen B; Cherian, Julie; Hausmann, Jonathan S; Miettunen, Paivi; Cellucci, Tania; Nuruzzaman, Farzana; Taneja, Angela; Barron, Karyl S; Hollander, Matthew C; Lapidus, Sivia K; Li, Suzanne C; Ozen, Seza; Girschick, Hermann; Laxer, Ronald M; Dedeoglu, Fatma; Hedrich, Christian M; Ferguson, Polly J
2017-11-07
To develop standardized treatment regimens for chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis (CRMO) to enable comparative effectiveness treatment studies. Virtual and face-to-face discussions and meetings were held within the CNO subgroup of the Childhood Arthritis and Rheumatology Research Alliance (CARRA). A literature search was conducted, and CARRA membership was surveyed to evaluate available treatment data and identify current treatment practices. Nominal group technique was used to achieve consensus on treatment plans for CNO refractory to non-steroidal anti-inflammatory drug (NSAID) monotherapy and/or with active spinal lesions. Three consensus treatment plans (CTPs) were developed for the first 12 months of therapy for CNO patients refractory to NSAID monotherapy and/or with active spinal lesions. The three CTPs are: (1) methotrexate or sulfasalazine, (2) tumor necrosis factor (TNF)-alpha inhibitors with optional use of methotrexate, and (3) bisphosphonates. Short courses of glucocorticoids and continuation of NSAIDs are permitted for all regimens. Consensus was achieved on these CTPs among CARRA members. Consensus was also reached on subject eligibility criteria, initial evaluations that should be conducted prior to the initiation of CTPs, and data items to collect to assess treatment response. Three consensus treatment plans were developed for pediatric patients with CNO refractory to NSAIDs and/or with active spinal lesions. Use of these CTPs will provide additional information on efficacy and will generate meaningful data for comparative effectiveness research in CNO. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
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Gökbuget, Nicola; Dombret, Hervè; Ribera, Jose-Maria; Fielding, Adele K.; Advani, Anjali; Bassan, Renato; Chia, Victoria; Doubek, Michael; Giebel, Sebastian; Hoelzer, Dieter; Ifrah, Norbert; Katz, Aaron; Kelsh, Michael; Martinelli, Giovanni; Morgades, Mireia; O’Brien, Susan; Rowe, Jacob M.; Stieglmaier, Julia; Wadleigh, Martha; Kantarjian, Hagop
2016-01-01
Adults with relapsed/refractory acute lymphoblastic leukemia have an unfavourable prognosis, which is influenced by disease and patient characteristics. To further evaluate these characteristics, a retrospective analysis of 1,706 adult patients with Ph-negative relapsed/refractory B-precursor acute lymphoblastic leukemia diagnosed between 1990–2013 was conducted using data reflecting the standard of care from 11 study groups and large centers in Europe and the United States. Outcomes included complete remission, overall survival, and realization of stem cell transplantation after salvage treatment. The overall complete remission rate after first salvage was 40%, ranging from 35%–41% across disease status categories (primary refractory, relapsed with or without prior transplant), and was lower after second (21%) and third or greater (11%) salvage. The overall complete remission rate was higher for patients diagnosed from 2005 onward (45%, 95% CI: 39%–50%). One- and three-year survival rates after first, second, and third or greater salvage were 26% and 11%, 18% and 6%, and 15% and 4%, respectively, and rates were 2%–5% higher among patients diagnosed from 2005. Prognostic factors included younger age, longer duration of first remission, and lower white blood cell counts at primary diagnosis. This large dataset can provide detailed reference outcomes for patients with relapsed/refractory Ph-negative B-precursor acute lymphoblastic leukemia. clinicaltrials.gov identifier: 02003612 PMID:27587380
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Clinical outcomes of intravenous immunoglobulin therapy in refractory uveitis.
Garcia-Geremias, M; Carreño, E; Epps, S J; Lee, R W J; Dick, A D
2015-04-01
Intravenous immunoglobulin (IVIg) therapy has multiple mechanisms of immunomodulatory action. We wished therefore to assess its efficacy in a spectrum of patients with refractory uveitis. Retrospective review of clinical charts was conducted to document response to IVIg treatment in consecutive patients with treatment-refractory uveitis. Main outcome measures were control of intraocular inflammation, visual acuity, progression of the disease, and complications. Four (two male) patients, with a mean age at the beginning of the treatment of 47 years (range: 39-64), were included in the study. Indication for treatment was patients with active non-infectious uveitis refractory to steroids and immunomodulatory therapy. All patients received a course of 0.5 g/kg per day of IVIg for three consecutive days, repeating this course at a mean of 11 week (range: 2-39 weeks) intervals when indicated clinically. The median duration of the IVIg therapy was 7 months (range: 3-14 months). In three patients treatment resulted in stabilisation and prevention of progression of the disease, and additionally in two patients it facilitated a decrease in prednisolone dose. Treatment failed to induce long-term remission in one patient with recurrence of macular oedema. IVIg was well tolerated with neither immediate nor longer-term adverse events observed. In three out of four cases IVIg was an effective adjunctive therapy and well tolerated for the management of treatment-refractory uveitis.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Dangi, Beni B.; Kim, Yong S.; Krasnokutski, Serge A.
2015-05-20
We report on laboratory simulation experiments mimicking the chemical processing of model atmospheres of exoplanets containing C3 and C4 hydrocarbons at moderate temperatures of 400 K upon interaction of catalytic surfaces of micrometeoroids. By utilizing an ultrasonic levitator device and heating singly levitated particles under simulated microgravity conditions, Raman spectroscopy is utilized as a non-invasive tool to probe on line and in situ the conversion of C3 and C4 hydrocarbons to refractory carbonaceous matter on the surfaces of levitated particles. Secondary Ion Mass Spectrometry and electron microscopic imaging were also conducted to gain further insight into the elementary composition andmore » structures of the refractories formed. Our results provide compelling evidence that in the presence of a catalytic surface, which can be supplied in the form of micrometeoroids and atmospheric dust particles, hydrocarbon gases present in the atmospheres of exoplanets can be converted to refractory, carbon-rich carbonaceous matter of mainly graphitic structure with a carbon content of at least 90% at elevated temperatures. This finding might explain the low methane to carbon monoxide (CH{sub 4}–CO) ratio in the hot Neptune GJ 436b, where the abundant methane photochemically converts to higher order hydrocarbons and ultimately to refractory graphite-like carbon in the presence of a silicon surface.« less
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Hypercalcemic crisis and primary hyperparathyroidism: Cause of an unusual electrical storm.
Guimarães, Tatiana; Nobre Menezes, Miguel; Cruz, Diogo; do Vale, Sónia; Bordalo, Armando; Veiga, Arminda; Pinto, Fausto J; Brito, Dulce
2017-12-01
Hypercalcemia is a known cause of heart rhythm disorders, however its association with ventricular arrhythmias is rare. The authors present a case of a fifty-three years old male patient with a ischemic and ethanolic dilated cardiomyopathy, and severely reduced ejection fraction, carrier of cardiac resynchronization therapy (CRT) with cardioverter defibrillator (ICD), admitted in the emergency department with an electrical storm, with multiple appropriated ICD shocks, refractory to antiarrhythmic therapy. In the etiological investigation was documented severe hypercalcemia secondary to primary hyperparathyroidism undiagnosed until then. Only after the serum calcium level reduction ventricular tachycardia was stopped. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.
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Feasibility Study for Casting of High Temperature Refractory Superalloy Composites
NASA Technical Reports Server (NTRS)
Lee, Jonathan A.
1998-01-01
Abstract This study investigated the feasibility of using conventional casting technique to fabricate refractory wires reinforced superalloy composites. These composites were being developed for advanced rocket engine turbine blades and other high temperature applications operating up to 2000 F. Several types of refractory metal wires such as W- Th, W-Re, Mo-Hf-C and W-HF-C reinforced waspaloy were experimentally cast and heat treated at 2000 F up to 48 hrs. Scanning electron microscope analysis was conducted in regions adjacent to the wire-matrix interface to determine the reaction zone and chemical compatibility resulting from material interdiffusion. It was concluded that fabrication using conventional casting may be feasible because the wire-matrix reaction zone thickness was comparable to similar composites produced by arc-sprayed monotape with hot isostatic pressing technique, Moreover, it was also found that the chemical compatibility could be improved significantly through a slight modification of the superalloy matrix compositions.
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Evaluation of olivine refractories for TES
NASA Astrophysics Data System (ADS)
Gay, B. M.; Cochrane, R. L.; Palmour, H., III; Paisley, M. J.
1982-02-01
The principal objectives of this program are to (1) experimentally determine the degree of improvement in thermal and mechanical performance that can be obtained with an olivine thermal storage brick made of domestic materials using advanced processing techniques compared with state-of-the-art as represented by commercial European bricks, (2) conduct an assessment of existing German ceramic process technology and determine its adaptability to domestic raw materials and manufacturing practices, and (3) investigate, on a limited basis, method for further improvement of domestic-olivine brick. To date, accomplishments include (1) installation of improved, computer-based instrumentation, (2) the use of this system to determine performance characteristics of a set of heat storage refractories under cyclic use conditions, (3) acquisition of the services of a knowledgeable European consultant, (4) continued lab-scale process/property optimization studies, and (5) comparative testing of olivine-based and magnesite-based heat storage refractories in the calorimetric test facility at Purdue University.
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Emergency catheter ablation in critical patients
Tebbenjohanns, Jürgen; Rühmkorf, Klaus
2010-01-01
Emergency catheter ablation is justified in critical patients with drug-refractory life-threatening arrhythmias. The procedure can be used for ablation of an accessory pathway in preexcitation syndrome with high risk of ventricular fibrillation and in patients with shock due to ischemic cardiomyopathy and incessant ventricular tachycardia. Emergency catheter ablation can also be justified in patients with an electrical storm of the implanted cardioverter-defibrillator or in patients with idiopathic ventricular fibrillation. PMID:20606793
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SNAP-8 refractory boiler development program
NASA Technical Reports Server (NTRS)
Fuller, R. A.
1974-01-01
Performance and endurance tests of the SNAP-8, SN-1 refractory metal boiler are described. The tests were successful and indicated that the boiler heat transfer area could be reduced significantly primarily because of the wetting characteristics of mercury on tantalum in a contaminant-free environment. A continuous endurance test of more than 10,000 hours was conducted without noticeable change in the thermal performance of the boiler. A conclusion of the metallographic examination of the boiler following the endurance test was that expected boiler life would be of the order of 40,000 hours at observed corrosion rates.
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Synthetic Coal Slag Infiltration into Varying Refractory Materials
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kaneko, Tetsuya K; Thomas, Hugh; Bennett, James P
The infiltrations of synthetic coal slag into 99%Al{sub 2}O{sub 3}, 85%Al{sub 2}O{sub 3}–15%SiO{sub 2}, and 90%Cr{sub 2}O{sub 3}–10%Al{sub 2}O{sub 3} refractories with a temperature gradient induced along the penetration direction were compared to one another. The infiltrating slag was synthesized with a composition that is representative of an average of the ash contents from U S coal feedstock. Experiments were conducted with a hot-face temperature of 1450°C in a CO/CO{sub 2} atmosphere. Minimal penetration was observed in the 90%Cr{sub 2}O{sub 3}–10%Al{sub 2}O{sub 3} material because interactions between the refractory and the slag produced a protective layer of FeCr{sub 2}O{sub 4},more » which impeded slag flow into the bulk of the refractory. After 5 h, the 99%Al{sub 2}O{sub 3} sample exhibited an average penetration of 12.7 mm whereas the 85%Al{sub 2}O{sub 3}–15%SiO{sub 2} sample showed 3.8 mm. Slag infiltrated into the 99%Al{sub 2}O{sub 3} and 85%Al{sub 2}O{sub 3}–15%SiO{sub 2} refractory systems by dissolving the respective refractories' matrix materials, which consist of fine Al{sub 2}O{sub 3} particles and an amorphous alumino-silicate phase. Due to enrichment in SiO{sub 2}, a network-former, infiltration into the 85%Al{sub 2}O{sub 3}–15%SiO{sub 2} system yielded a higher viscosity slag and hence, a shallower penetration depth. The results suggest that slag infiltration can be limited by interactions with the refractory through the formation of either a solid layer that physically impedes fluid flow or a more viscous slag that retards infiltration.« less
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Vijay, Sonam; Rawat, Manmeet; Adak, Tridibes; Dixit, Rajnikant; Nanda, Nutan; Srivastava, Harish; Sharma, Joginder K; Prasad, Godavarthi B K S; Sharma, Arun
2011-04-04
Anopheles culicifacies, the main vector of human malaria in rural India, is a complex of five sibling species. Despite being phylogenetically related, a naturally selected subgroup species B of this sibling species complex is found to be a poor vector of malaria. We have attempted to understand the differences between vector and non-vector Anopheles culicifacies mosquitoes in terms of transcriptionally activated nitric oxide synthase (AcNOS) physiologies to elucidate the mechanism of refractoriness. Identification of the differences between genes and gene products that may impart refractory phenotype can facilitate development of novel malaria transmission blocking strategies. We conducted a study on phylogenetically related susceptible (species A) and refractory (species B) sibling species of An. culicifacies mosquitoes to characterize biochemical and molecular differences in AcNOS gene and gene elements and their ability to inhibit oocyst growth. We demonstrate that in species B, AcNOS specific activity and nitrite/nitrates in mid-guts and haemolymph were higher as compared to species A after invasion of the mid-gut by P. vivax at the beginning and during the course of blood feeding. Semiquantitative RT-PCR and real time PCR data of AcNOS concluded that this gene is more abundantly expressed in midgut of species B than in species A and is transcriptionally upregulated post blood meals. Dietary feeding of L-NAME along with blood meals significantly inhibited midgut AcNOS activity leading to an increase in oocyst production in An. culicifacies species B. We hypothesize that upregulation of mosquito innate cytotoxicity due to NOS in refractory strain to Plasmodium vivax infection may contribute to natural refractoriness in An. culicifacies mosquito population. This innate capacity of refractory mosquitoes could represent the ancestral function of the mosquito immune system against the parasite and could be utilized to understand the molecular basis of refractoriness in planning effective vector control strategies.
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Vijay, Sonam; Rawat, Manmeet; Adak, Tridibes; Dixit, Rajnikant; Nanda, Nutan; Srivastava, Harish; Sharma, Joginder K.; Prasad, Godavarthi B. K. S.; Sharma, Arun
2011-01-01
Background Anopheles culicifacies, the main vector of human malaria in rural India, is a complex of five sibling species. Despite being phylogenetically related, a naturally selected subgroup species B of this sibling species complex is found to be a poor vector of malaria. We have attempted to understand the differences between vector and non-vector Anopheles culicifacies mosquitoes in terms of transcriptionally activated nitric oxide synthase (AcNOS) physiologies to elucidate the mechanism of refractoriness. Identification of the differences between genes and gene products that may impart refractory phenotype can facilitate development of novel malaria transmission blocking strategies. Methodology/Principal Findings We conducted a study on phylogenetically related susceptible (species A) and refractory (species B) sibling species of An. culicifacies mosquitoes to characterize biochemical and molecular differences in AcNOS gene and gene elements and their ability to inhibit oocyst growth. We demonstrate that in species B, AcNOS specific activity and nitrite/nitrates in mid-guts and haemolymph were higher as compared to species A after invasion of the mid-gut by P. vivax at the beginning and during the course of blood feeding. Semiquantitative RT-PCR and real time PCR data of AcNOS concluded that this gene is more abundantly expressed in midgut of species B than in species A and is transcriptionally upregulated post blood meals. Dietary feeding of L-NAME along with blood meals significantly inhibited midgut AcNOS activity leading to an increase in oocyst production in An. culicifacies species B. Conclusions/Significance We hypothesize that upregulation of mosquito innate cytotoxicity due to NOS in refractory strain to Plasmodium vivax infection may contribute to natural refractoriness in An. culicifacies mosquito population. This innate capacity of refractory mosquitoes could represent the ancestral function of the mosquito immune system against the parasite and could be utilized to understand the molecular basis of refractoriness in planning effective vector control strategies. PMID:21483693
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Clinical Outcomes and Quality of Life Following Surgical Treatment for Refractory Epilepsy
Liu, Shi-Yong; Yang, Xiao-Lin; Chen, Bing; Hou, Zhi; An, Ning; Yang, Mei-Hua; Yang, Hui
2015-01-01
Abstract Surgery for refractory epilepsy is widely used but the efficacy of this treatment for providing a seizure-free outcome and better quality of life remains unclear. This study aimed to update current evidence and to evaluate the effects of surgery on quality of life in patients with refractory epilepsy. A systematic review and meta-analysis of the literature were conducted and selected studies included 2 groups of refractory epilepsy patients, surgical and nonsurgical. The studies were assessed using the Newcastle–Ottawa Scale. The primary outcome was the seizure-free rate. The secondary outcome was quality of life. Adverse events were also reviewed. After screening, a total of 20 studies were selected: 8 were interventional, including 2 randomized controlled trials, and 12 were observational. All of the studies comprised 1959 patients with refractory epilepsy. The seizure-free rates were significantly higher for patients who received surgery compared with the patients who did not; the combined odds ratio was 19.35 (95% CI = 12.10–30.95, P < 0.001). After adjusting for publication bias the combined odds ratio was 10.25 (95% CI = 5.84–18.00). In both the interventional and observational studies, patients treated surgically had a significantly better quality of life compared with the patients not treated surgically. Complications were listed in 3 studies and the rates were similar in surgical and nonsurgical patients. Our meta-analysis found that for patients with refractory epilepsy, surgical treatment appears to provide a much greater likelihood of seizure-free outcome than nonsurgical treatment, although there is a need for more studies, particularly randomized studies, to confirm this conclusion. Based on more limited data, surgical treatment also appeared to provide a better quality of life and did not seem to increase complications. PMID:25674741
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Matsuoka, A J; Abbas, P J; Rubinstein, J T; Miller, C A
2000-11-01
Experimental results from humans and animals show that electrically evoked compound action potential (EAP) responses to constant-amplitude pulse train stimulation can demonstrate an alternating pattern, due to the combined effects of highly synchronized responses to electrical stimulation and refractory effects (Wilson et al., 1994). One way to improve signal representation is to reduce the level of across-fiber synchrony and hence, the level of the amplitude alternation. To accomplish this goal, we have examined EAP responses in the presence of Gaussian noise added to the pulse train stimulus. Addition of Gaussian noise at a level approximately -30 dB relative to EAP threshold to the pulse trains decreased the amount of alternation, indicating that stochastic resonance may be induced in the auditory nerve. The use of some type of conditioning stimulus such as Gaussian noise may provide a more 'normal' neural response pattern.
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2018-06-13
Advanced Malignant Solid Neoplasm; RB1 Positive; Recurrent Childhood Ependymoma; Recurrent Ewing Sarcoma; Recurrent Glioma; Recurrent Hepatoblastoma; Recurrent Kidney Wilms Tumor; Recurrent Langerhans Cell Histiocytosis; Recurrent Malignant Germ Cell Tumor; Recurrent Malignant Glioma; Recurrent Medulloblastoma; Recurrent Neuroblastoma; Recurrent Non-Hodgkin Lymphoma; Recurrent Osteosarcoma; Recurrent Peripheral Primitive Neuroectodermal Tumor; Recurrent Rhabdoid Tumor; Recurrent Rhabdomyosarcoma; Recurrent Soft Tissue Sarcoma; Refractory Ependymoma; Refractory Ewing Sarcoma; Refractory Glioma; Refractory Hepatoblastoma; Refractory Langerhans Cell Histiocytosis; Refractory Malignant Germ Cell Tumor; Refractory Malignant Glioma; Refractory Medulloblastoma; Refractory Neuroblastoma; Refractory Non-Hodgkin Lymphoma; Refractory Osteosarcoma; Refractory Peripheral Primitive Neuroectodermal Tumor; Refractory Rhabdoid Tumor; Refractory Rhabdomyosarcoma; Refractory Soft Tissue Sarcoma
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Jessurun, G A; DeJongste, M J; Hautvast, R W; Tio, R A; Brouwer, J; van Lelieveld, S; Crijns, H J
1999-10-01
The present study assessed the reoccurrence of myocardial ischemia after withholding electrical neurostimulation. After randomization, in the study or withdrawal group, spinal cord stimulation (SCS) was set active during the first 4 weeks, followed by 4 weeks of withholding stimulation. In the control group, SCS was switched off during 4 weeks before the end of the study. The control group had no crossover period. Measurements were done at baseline, then after 4 and 8 weeks. The first periods at 4 weeks of each sequence of both groups were compared. In addition, a comparison of clinical variables was performed between the study group 4 weeks after withholding stimulation and the control group 4 weeks following randomization. A total number of 24 patients with refractory angina and an implanted spinal cord stimulator were included in the study (n = 12) and control group. Angina pectoris complaints, nitroglycerin intake, ischemia, and heart rate variability using 48-hour ambulatory electrocardiographic monitoring were assessed. In addition, neurohormonal status and symptom-limited aerobic capacity were evaluated. There was no increase of anginal complaints or ischemia after withholding stimulation. Neurohormonal levels and aerobic capacity were not altered. We conclude that there is no adverse clinical rebound phenomenon after withholding neurostimulation in patients with refractory angina pectoris.
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Dimov, Luiz Fabio; Toniolo, Elaine Flamia; Alonso-Matielo, Heloísa; de Andrade, Daniel Ciampi; Garcia-Larrea, Luis; Ballester, Gerson; Teixeira, Manoel Jacobsen; Dale, Camila Squarzoni
2018-07-02
Cortical electrical stimulation (CES) has shown to be an effective therapeutic alternative for neuropathic pain refractory to pharmacological treatment. The primary motor cortex(M1) was the main cortical target used in the vast majority of both invasive and non-invasive studies. Despite positive results M1-based approaches still fail to relieve pain in a significant proportion of individuals. It has been advocated that the direct stimulation of cortical areas directly implicated in the central integration of pain could increase the efficacy of analgesic brain stimulation. Here, we evaluated the behavioral effects of electrical stimulation of the insular cortex (ESI) on pain sensitivity in an experimental rat model of peripheral neuropathy, and have described the pathways involved. Animals underwent chronic constriction of the sciatic nerve in the right hind limb and had concentric electrodes implanted in the posterior dysranular insular cortex. Mechanical nociception responses were evaluated before and at the end of a 15-min session of ESI (60Hz, 210μs, 1V). ESI reversed mechanical hypersensitivity in the paw contralateral to the brain hemisphere stimulated, without inducing motor impairment in the open-field test. Pharmacological blockade of μ-opioid (MOR) or type 1-cannabinoid receptors (CB1R) abolished ESI-induced antinociceptive effects. Evaluation of CB1R and MOR spatial expression demonstrated differential modulation of CB1R and MOR in the periaqueductal gray matter (PAG) of ESI-treated rats in sub-areas involved in pain processing/modulation. These results indicate that ESI induces antinociception by functionally modulating opioid and cannabinoid systems in the PAG pain circuitry in rats with experimentally induced neuropathic pain. Copyright © 2017 Elsevier B.V. All rights reserved.
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A retrospective study on the management of patients with rituximab refractory follicular lymphoma.
Solal-Céligny, Philippe; Leconte, Pierre; Bardet, Aurélie; Hernandez, Juana; Troussard, Xavier
2018-01-01
Given that there are currently no clear recommendations regarding therapeutic options for rituximab refractory/relapsed follicular lymphoma patients, this study aimed to describe the real-life management of patients with refractory follicular lymphoma after systemic rituximab-containing regimens (rFL), and rFL patient characteristics. In this retrospective, national, multicentre study, descriptive analyses were mainly performed according to rituximab-containing regimen at rFL diagnosis [rituximab monotherapy (R-MONO), rituximab + chemotherapy (R-COMBO), and ongoing rituximab maintenance (R-MAINTAIN)]. The 459 analysed patients experienced rituximab-refractoriness between October 2013 and September 2015: R-MONO: 58 (13%), R-COMBO: 197 (43%), R-MAINTAIN: 204 (44%). Post-refractoriness strategies were heterogeneous: idelalisib ± rituximab (22%), without anti-lymphoma treatment (21%), rituximab-chemotherapy (21%) and stem cell transplantation (18%). Rituximab was continued in combination in 41% of cases. Chosen strategies varied according to patient age (without anti-lymphoma treatment: 28% of patients if ≥65 years vs. 12% if <65 years old; stem-cell transplantation: 4% vs. 38%), treatment line at rFL, FL International Prognostic Index score and prior treatment. This French retrospective study, the first one conducted in a large cohort of rFL patients, showed that further strategies were highly heterogeneous, depending notably on patient characteristics and previous treatment. These data are the basis for a better understanding of rFL management and for the design of clinical trials in these patients. © 2017 John Wiley & Sons Ltd.
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Uranium carbide fission target R&D for RIA - an update
NASA Astrophysics Data System (ADS)
Greene, J. P.; Levand, A.; Nolen, J.; Burtseva, T.
2004-12-01
For the Rare Isotope Accelerator (RIA) facility, ISOL targets employing refractory compounds of uranium are being developed to produce radioactive ions for post-acceleration. The availability of refractory uranium compounds in forms that have good thermal conductivity, relatively high density, and adequate release properties for short-lived isotopes remains an important issue. Investigations using commercially obtained uranium carbide material and prepared into targets involving various binder materials have been carried out at ANL. Thin sample pellets have been produced for measurements of thermal conductivity using a new method based on electron bombardment with the thermal radiation observed using a two-color optical pyrometer and performed on samples as a function of grain size, pressing pressure and sintering temperature. Manufacture of uranium carbide powder has now been achieved at ANL. Simulations have been carried out on the thermal behavior of the secondary target assembly incorporating various heat shield configurations.
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Takahara, Akira; Suzuki, Sanae; Hagiwara, Mihoko; Nozaki, Shuhei; Sugiyama, Atsushi
2013-01-01
We assessed the effects of oseltamivir on the conduction velocity and effective refractory period in the guinea-pig atrium in comparison with those of a class Ic antiarrhythmic drug pilsicainide. The recording and stimulating electrodes were attached on the epicardium close to the sinus nodal region and on the left atrial appendage. Oseltamivir (10-100 µM) as well as pilsicainide (1-10 µM) decreased the atrial conduction velocity in a frequency-dependent manner. Both drugs also increased the effective refractory period in both atria; but the frequency-dependent property of oseltamivir was lacking in the left atrium, and it was less obvious in the right atrium compared with that of pilsicainide. These results suggest that oseltamivir can directly modify the electrophysiological functions in the guinea-pig atrium possibly via combination of Na(+) and K(+) channel-blocking actions.
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Zhang, Ming; Wang, Zhou; Li, Penghui; Zhang, Hua; Xie, Li
2017-07-01
An important portion of organic matter and colorants still remain in the biologically treated distillery wastewater, leaving the dark brown and odorous downstream with the heavy loading of chemical oxygen demand and the potential of forming disinfection byproducts. However, those bio-recalcitrant colorants have not been clearly recognized. The current study investigated the features of the bio-refractory organic matter and colorants in a typical distillery effluent, cassava distillery wastewater; special attention was paid to their change and behaviors in the coagulation treatment following the bio-processes. The wastewater analyses denoted that the fraction of high molecular weight (1-50 kDa and >50 kDa) became predominant after the anaerobic-aerobic processes. Importantly, the lignin breakdown products, melanoidins and lignin phenols were confirmed to be the leading colored components, according to the parallel factor analysis of fluorescence excitation-emission matrixes results. Compared with lignin phenols, the former two types of colorants exhibited stronger bio-refractory activity and resulted in smaller color reduction after the aerobic treatment. Neither advanced oxidation nor adsorption could perform efficiently as post-treatment for decolorization in this study. Nevertheless, high removal of color and dissolved organic matter (∼94.0% and ∼78.3%, respectively) could be achieved by the FeCl 3 -involved coagulation under the optimal conditions. The ferric coagulant was found to preferably interact with the aromatic compounds (such as lignin derivatives) and melanoidins via either surface complexation or electric charge neutralization, or both. The findings presented herein might provide an insight into the evaluation of bio-refractory organic colorants and the Fe(III)-involved decolorization mechanisms of ethanol production wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Passive safety device and internal short tested method for energy storage cells and systems
Keyser, Matthew; Darcy, Eric; Long, Dirk; Pesaran, Ahmad
2015-09-22
A passive safety device for an energy storage cell for positioning between two electrically conductive layers of the energy storage cell. The safety device also comprising a separator and a non-conductive layer. A first electrically conductive material is provided on the non-conductive layer. A first opening is formed through the separator between the first electrically conductive material and one of the electrically conductive layers of the energy storage device. A second electrically conductive material is provided adjacent the first electrically conductive material on the non-conductive layer, wherein a space is formed on the non-conductive layer between the first and second electrically conductive materials. A second opening is formed through the non-conductive layer between the second electrically conductive material and another of the electrically conductive layers of the energy storage device. The first and second electrically conductive materials combine and exit at least partially through the first and second openings to connect the two electrically conductive layers of the energy storage device at a predetermined temperature.
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Rivastigmine for refractory REM behavior disorder in mild cognitive impairment.
Brunetti, Valerio; Losurdo, Anna; Testani, Elisa; Lapenta, Leonardo; Mariotti, Paolo; Marra, Camillo; Rossini, Paolo Maria; Della Marca, Giacomo
2014-03-01
Mild Cognitive Impairment (MCI) and REM Behavior Disorder (RBD) are both associated with a degeneration of ponto-medullary cholinergic pathways. We conducted a placebo-controlled, cross-over pilot trial of Rivastigmine (RVT) in 25 consecutive patients with MCI, who presented RBD refractory to conventional first-line treatments (melatonin up to 5 mg/day and clonazepam up to 2 mg/day). RVT treatment was followed by a significant reduction of RBD episodes when compared with placebo. Our data suggest that, in MCI patients with RBD resistant to conventional therapies (muscle relaxants benzodiazepines or melatonin,) treatment with RVT may induce a reduction in the frequency of RBD episodes compared to placebo.
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Light, Strong Insulating Tiles
NASA Technical Reports Server (NTRS)
Cordia, E.; Schirle, J.
1987-01-01
Improved lightweight insulating silica/aluminum borosilicate/silicon carbide tiles combine increased tensile strength with low thermal conductivity. Changes in composition substantially improve heat-insulating properties of silica-based refractory tile. Silicon carbide particles act as high-emissivity radiation scatterers in tile material.
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Non-Contact Measurements of Creep Properties of Refractory Materials
NASA Technical Reports Server (NTRS)
Lee, Jonghyun; Bradshaw, Richard C.; Hyers, Robert W.; Rogers, Jan R.; Rathz, Thomas J.; Wall, James J.; Choo, Hahn; Liaw, Peter
2006-01-01
State-of-the-art technologies for hypersonic aircraft, nuclear electric/thermal propulsion for spacecraft, and more efficient jet engines are driving ever more demanding needs for high-temperature (>2000 C) materials. At such high temperatures, creep rises as one of the most important design factors to be considered. Since conventional measurement techniques for creep resistance are limited to about 17OO0C, a new technique is in demand for higher temperatures. This paper presents a non-contact method using electrostatic levitation (ESL) which is applicable to both metallic and non-metallic materials. The samples were rotated quickly enough to cause creep deformation by centrifugal acceleration. The deformation of the samples was captured with a high speed camera and then the images were analyzed to estimate creep resistance. Finite element analyses were performed and compared to the experiments to verify the new method. Results are presented for niobium and tungsten, representative refractory materials at 2300 C and 2700 C respectively.
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Cao, Xian; Song, Hai-Liang; Yu, Chun-Yan; Li, Xian-Ning
2015-01-01
In this study, the soil microbial fuel cells (MFCs) were constructed in the topsoil contaminated with toxic refractory organic pesticide, hexachlorobenzene (HCB). The performance of electricity generation and HCB degradation in the soil-MFCs were investigated. The HCB degradation pathway was analyzed based on the determination of degradation products and intermediates. Experimental results showed that the HCB removal efficiencies in the three groups (soil MFCs group, open circuit control group and no adding anaerobic sludge blank group) were 71.15%, 52.49% and 38.92%, respectively. The highest detected power density was 77.5 mW/m(2) at the external resistance of 1000 Ω. HCB was degraded via the reductive dechlorination pathway in the soil MFC under anaerobic condition. The existence of the anode promoted electrogenic bacteria to provide more electrons to increase the metabolic reactions rates of anaerobic bacteria was the main way which could promote the removal efficiencies of HCB in soil MFC. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Buckstein, Rena; Kuruvilla, John; Chua, Neil; Lee, Christina; Macdonald, David A; Al-Tourah, Abdulwahab J; Foo, Alison H; Walsh, Wendy; Ivy, S Percy; Crump, Michael; Eisenhauer, Elizabeth A
2011-05-01
There are limited effective therapies for most patients with relapsed diffuse large B-cell lymphoma (DLBCL). We conducted a phase II trial of the multi-targeted vascular endothelial growth factor receptor (VEGFR) kinase inhibitor, sunitinib, 37.5 mg given orally once daily in adult patients with relapsed or refractory DLBCL. Of 19 enrolled patients, 17 eligible patients were evaluable for toxicity and 15 for response. No objective responses were seen and nine patients achieved stable disease (median duration 3.4 months). As a result, the study was closed at the end of the first stage. Grades 3-4 neutropenia and thrombocytopenia were observed in 29% and 35%, respectively. There was no relationship between change in circulating endothelial cell numbers (CECs) and bidimensional tumor burden over time. Despite some activity in solid tumors, sunitinib showed no evidence of response in relapsed/refractory DLBCL and had greater than expected hematologic toxicity.
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Buckstein, Rena; Kuruvilla, John; Chua, Neil; Lee, Christina; Macdonald, David A; Al-Tourah, Abdulwahab J; Foo, Alison H; Walsh, Wendy; Ivy, S Percy; Crump, Michael; Eisenhauer, Elizabeth A
2011-01-01
There are limited effective therapies for most patients with relapsed diffuse large B-cell lymphoma (DLBCL). We conducted a phase II trial of the multi-targeted vascular endothelial growth factor receptor (VEGFR) kinase inhibitor, sunitinib, 37.5 mg given orally once daily in adult patients with relapsed or refractory DLBCL. Of 19 enrolled patients, 17 eligible patients were evaluable for toxicity and 15 for response. No objective responses were seen and nine patients achieved stable disease (median duration 3.4 months). As a result, the study was closed at the end of the first stage. Grades 3—4 neutropenia and thrombocytopenia were observed in 29% and 35%, respectively. There was no relationship between change in circulating endothelial cell numbers (CECs) and bidimensional tumor burden over time. Despite some activity in solid tumors, sunitinib showed no evidence of response in relapsed/refractory DLBCL and had greater than expected hematologic toxicity. PMID:21463120
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Hall, David R [Provo, UT; Fox, Joe [Spanish Fork, UT
2008-01-15
A transmission system in a downhole component comprises a data transmission element in both ends of the downhole component. Each data transmission element houses an electrically conducting coil in a MCEI circular trough. An electrical conductor connects both the transmission elements. The electrical conductor comprises at least three electrically conductive elements insulated from each other. In the preferred embodiment the electrical conductor comprises an electrically conducting outer shield, an electrically conducting inner shield and an electrical conducting core. In some embodiments of the present invention, the electrical conductor comprises an electrically insulating jacket. In other embodiments, the electrical conductor comprises a pair of twisted wires. In some embodiments, the electrical conductor comprises semi-conductive material.
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Study on the RF inductively coupled plasma spheroidization of refractory W and W-Ta alloy powders
NASA Astrophysics Data System (ADS)
Chenfan, YU; Xin, ZHOU; Dianzheng, WANG; Neuyen VAN, LINH; Wei, LIU
2018-01-01
Spherical powders with good flowability and high stacking density are mandatory for powder bed additive manufacturing. Nevertheless, the preparation of spherical refractory tungsten and tungsten alloy powders is a formidable task. In this paper, spherical refractory metal powders processed by high-energy stir ball milling and RF inductively coupled plasma were investigated. By utilizing the technical route, pure spherical tungsten powders were prepared successfully, the flowability increased from 10.7 s/50 g to 5.5 s/50 g and apparent density increased from 6.916 g cm-3 to 11.041 g cm-3. Alloying element tantalum can reduce the tendency to micro-crack during tungsten laser melting and rapid solidification process. Spherical W-6Ta (%wt) powders were prepared in this way, homogeneous dispersion of tantalum in a tungsten matrix occurred but a small amount of flake-like shape particles appeared after high-energy stir ball milling. The flake-like shape particles can hardly be spheroidized in subsequent RF inductively coupled plasma process, might result from the unique suspended state of flaky particles under complex electric and magnetic fields as well as plasma-particle heat exchange was different under various turbulence models. As a result, the flake-like shape particles cannot pass through the high-temperature area of thermal plasma torch and cannot be spheroidized properly.
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Osadchii, Oleg E
2012-11-01
Flecainide is nonselective Na(+) channel blocker which may also inhibit I(Kr), the rapid component of the delayed rectifier. This study was designed to explore if proarrhythmic responses to flecainide noted in cardiac patients may be partly attributed to abnormal changes in repolarization and refractoriness. Monophasic action potential duration (APD) and effective refractory periods (ERP) were assessed at distinct epicardial and endocardial sites along with volume-conducted ECG recordings in isolated perfused guinea-pig heart preparations. Flecainide was found to prolong ventricular repolarization, with effect being greater at the left ventricular compared with the right ventricular epicardium. This change translated to reversal of the normal right ventricular-to-left ventricular transepicardial APD difference determined before drug infusion. An inverse correlation between local epicardial APD and corresponding activation time values seen at baseline was eliminated in flecainide-treated hearts, indicating the activation-to-repolarization uncoupling. Over transmural plane, flecainide produced a greater ERP lengthening at endocardium than epicardium, thus markedly increasing ERP dispersion across ventricular wall. Spontaneous short-lasting episodes of monomorphic ventricular tachycardia were observed in 45% of heart preparations upon flecainide infusion. In conclusion, in nonischemic guinea-pig heart, flecainide-induced proarrhythmia may be partly attributed to abnormal spatial gradients in repolarization and refractoriness and impaired transepicardial activation-to-repolarization coupling.
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Small Reactor Designs Suitable for Direct Nuclear Thermal Propulsion: Interim Report
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bruce G. Schnitzler
Advancement of U.S. scientific, security, and economic interests requires high performance propulsion systems to support missions beyond low Earth orbit. A robust space exploration program will include robotic outer planet and crewed missions to a variety of destinations including the moon, near Earth objects, and eventually Mars. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. In NASA's recent Mars Design Reference Architecture (DRA) 5.0 study, nuclear thermal propulsion (NTP) was again selectedmore » over chemical propulsion as the preferred in-space transportation system option for the human exploration of Mars because of its high thrust and high specific impulse ({approx}900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. The recently announced national space policy2 supports the development and use of space nuclear power systems where such systems safely enable or significantly enhance space exploration or operational capabilities. An extensive nuclear thermal rocket technology development effort was conducted under the Rover/NERVA, GE-710 and ANL nuclear rocket programs (1955-1973). Both graphite and refractory metal alloy fuel types were pursued. The primary and significantly larger Rover/NERVA program focused on graphite type fuels. Research, development, and testing of high temperature graphite fuels was conducted. Reactors and engines employing these fuels were designed, built, and ground tested. The GE-710 and ANL programs focused on an alternative ceramic-metallic 'cermet' fuel type consisting of UO2 (or UN) fuel embedded in a refractory metal matrix such as tungsten. The General Electric program examined closed loop concepts for space or terrestrial applications as well as open loop systems for direct nuclear thermal propulsion. Although a number of fast spectrum reactor and engine designs suitable for direct nuclear thermal propulsion were proposed and designed, none were built. This report summarizes status results of evaluations of small nuclear reactor designs suitable for direct nuclear thermal propulsion.« less
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In-Situ Wire Damage Detection System
NASA Technical Reports Server (NTRS)
Jolley, Scott T. (Inventor); Gibson, Tracy L. (Inventor); Medelius, Pedro J. (Inventor); Roberson, Luke B. (Inventor); Tate, Lanetra C. (Inventor); Smith, Trent M. (Inventor); Williams, Martha K. (Inventor)
2014-01-01
An in-situ system for detecting damage in an electrically conductive wire. The system includes a substrate at least partially covered by a layer of electrically conductive material forming a continuous or non-continuous electrically conductive layer connected to an electrical signal generator adapted to delivering electrical signals to the electrically conductive layer. Data is received and processed to identify damage to the substrate or electrically conductive layer. The electrically conductive material may include metalized carbon fibers, a thin metal coating, a conductive polymer, carbon nanotubes, metal nanoparticles or a combination thereof.
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Hussein, Ayman A; Panchabhai, Tanmay S; Budev, Marie M; Tarakji, Khaldoun; Barakat, Amr F; Saliba, Walid; Lindsay, Bruce; Wazni, Oussama M
2017-06-01
The authors report their experience with atrial fibrillation (AF) rates and ablation findings in lung transplant recipients. Pulmonary venous (PV) conduction recovery accounts for most failed atrial fibrillation (AF) catheter ablation procedures. Lung transplantation involves full surgical resection and replacement of the recipient's PVs with donor's PVs, which may represent the ultimate PV ablation. They followed 755 consecutive lung transplant recipients categorized based on transplant status (unilateral vs. bilateral) and pre-transplant AF. In patients without pre-transplant AF (n = 704), late AF (beyond 6 months after transplant) occurred in 2.5% and 3.3% of unilateral or bilateral lung transplants, respectively. In patients with pre-transplant AF (n = 51), AF recurred in 19.4% and 25.0% of bilateral and unilateral transplants, respectively. In a subset of patients who underwent left atrial ablations after transplant for recurrent refractory AF (n = 8), PV conduction recovery across the surgical anastomoses lines was observed in 22 of 26 previously disconnected PVs. Conduction recovery was observed in ≥1 vein in all but 1 patient. Re-isolation of the veins with additional substrate modification/flutter ablations successfully restored and maintained sinus rhythm in 7 of 8 patients. In lung transplant recipients who undergo full surgical resection of the PVs, a prior history of AF was associated with late AF, regardless of whether patients underwent single or bilateral lung transplantation. PV conduction recovery still occurred and was observed in most patients who underwent left atrial ablation procedures for recurrent AF. Copyright © 2017. Published by Elsevier Inc.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Sugawara, Shunsuke, E-mail: suga_shun@hotmail.com; Sone, Miyuki; Arai, Yasuaki
Purpose: Peritoneal venous shunts (PVSs) are widely used for palliating symptoms of refractory malignant ascites and are recognized as one of the practical methods. However, reliable clinical data are insufficient because most previous reports have been small studies from single centers. We conducted a retrospective, multicenter study to evaluate the safety and efficacy of radiologically placed PVSs in patients with malignant refractory ascites. Methods: A total of 133 patients with malignant ascites refractory to medical therapies were evaluated for patient characteristics, technical success, efficacy, survival times, adverse events, and changes in laboratory data. Results: PVSs were successfully placed in allmore » patients and were effective (i.e., improvement of ascites symptoms lasting 7 days or more) in 110 (82.7%). The median duration of symptom palliation was 26 days and median survival time was 41 days. The most frequent adverse event was PVS dysfunction, which occurred in 60 (45.1%) patients, among whom function was recovered with an additional minimally invasive procedure in 9. Abnormalities in coagulation (subclinical disseminated intravascular coagulation) occurred in 37 (27.8%) patients, although only 7 (5.3%) developed clinical disseminated intravascular coagulation. Other major adverse events were gastrointestinal bleeding (9.8%), sepsis (3.8%), and acute heart failure (3.0%). PVS was least effective in patients with elevated serum creatinine, bloody ascites, or gynecologic tumor. Conclusions: Radiological PVS is a technically feasible and effective method for palliating the symptoms from refractory malignant ascites, but preoperative evaluation and monitoring the postprocedural complications are mandatory to preclude severe adverse events after PVS.« less
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Propofol Infusion Syndrome in Refractory Status Epilepticus
Hwang, Woo Sub; Gwak, Hye Min; Seo, Dae-Won
2013-01-01
Background and Purpose: Propofol is used for treating refractory status epilepticus, which has high rate of mortality. Propofol infusion syndrome is a rare but often fatal syndrome, characterized by lactic acidosis, lipidemia, and cardiac failure, associated with propofol infusion over prolonged periods of time. We investigated the clinical factors that characterize propofol infusion syndrome to know the risk of them in refractory status epilepticus. Methods: This retrospective observation study was conducted in Samsung medical center from Jan. 2005 to Dec. 2009. Thirty two patients (19 males, 13 females, aged between 16 and 64 years), with refractory status epilepsy were included. Their clinical findings and treatment outcomes were evaluated retrospectively. We divided our patients into established status epilepticus (ESE) and refractory status epilepticus (RSE). And then the patients with RSE was further subdivided into propofol treatment group (RSE-P) and the other anesthetics treatment group (RSE-O). We analyzed the clinical characteristics by comparison of the groups. Results: There were significant differences of hypotension and lipid change between ESE and RSE (p<0.05). However, there was no significant difference between RSE-P and RSE-O groups. The hospital days were longer in RSE than in ESE (p=0.012) and treatment outcome was also worse in RSE than in ESE (p=0.007) but there were no significant differences of hospital stays and treatment outcome between RSE-P and RSE-O. Conclusions: RSE is very critical disease with high mortality, which may show as many clinical changes as propofol infusion syndrome. Therefore propofol infusion syndrome might be considered as one of the clinical manifestations of RSE. PMID:24649467
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Komaki, Yuga; Komaki, Fukiko; Micic, Dejan; Yamada, Akihiro; Suzuki, Yasuo; Sakuraba, Atsushi
2017-06-01
A limited option of therapies is available for hospitalized patients with severe steroid refractory ulcerative colitis (UC). Furthermore, there exists a paucity of direct comparisons between them. To provide a comparative evaluation of the efficacy and safety of pharmacologic therapies, we conducted a network meta-analysis combined with a benefit-risk analysis of randomized controlled trials (RCTs) performed in hospitalized patients with severe steroid refractory UC. Electronic databases were searched through November 2015 for RCTs evaluating the efficacy of therapies for severe steroid refractory hospitalized UC. The outcomes were clinical response, colectomy free rate, and severe adverse events leading to discontinuation of therapy. The primary endpoints were the rank of therapies based on network meta-analysis combined with benefit-risk analysis between clinical response and severe adverse events as well as colectomy free rate and severe adverse events. Eight RCTs of 421 patients were identified. Cyclosporine, infliximab, and tacrolimus as well as placebo were included in our analysis. Network meta-analysis with benefit-risk analysis simultaneously assessing clinical response and severe adverse events demonstrated the rank order of efficacy as infliximab, cyclosporine, tacrolimus, and placebo. Similar analysis for colectomy-free rate and severe adverse events demonstrated the same rank order of efficacy. The differences among infliximab, cyclosporine, and tacrolimus were small in all analyses. The results of the present comprehensive benefit-risk assessment using network meta-analysis provide RCT-based evidence on efficacy and safety of infliximab, cyclosporine, and tacrolimus for hospitalized patients with severe steroid refractory UC. © 2016 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.
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Soto, Marcelo; Sampietro-Colom, Laura; Sagarra, Joan; Brugada-Terradellas, Josep
2016-06-01
In Spain, 0.3% of patients with hypertension are refractory to conventional treatment. The complications resulting from deficient control of this condition can lead to poor quality of life for the patient and considerable health care costs. Barostim is an implantable device designed to lower blood pressure in these patients. The aim of this study was to analyze the cost-effectiveness of Barostim compared with drug therapy in hypertensive patients refractory to conventional treatment (at least 3 antihypertensive drugs, including 1 diuretic agent). We used a Markov model adapted to the epidemiology of the Spanish population to simulate the natural history of a cohort of patients with refractory hypertension over their lifetime. Data on the effectiveness of the treatments studied were obtained from the literature, and data on costs were taken from hospital administrative databases and official sources. Deterministic and probabilistic sensitivity analyses were conducted. Barostim increased the number of quality-adjusted life years by 0.78 and reduced the number of hypertension-associated clinical events. The incremental cost-effectiveness ratio in a cohort of men reached 68 726 euros per year of quality-adjusted life. One of the main elements that makes this technology costly is the need for battery replacement. The results were robust. Barostim is not a cost-effective strategy for the treatment of refractory hypertension in Spain. The cost-effectiveness ratio could be improved by future reductions in the cost of the battery. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Tooker, Angela C.; Felix, Sarah H.; Pannu, Satinderpall S.
A neural interface includes a first dielectric material having at least one first opening for a first electrical conducting material, a first electrical conducting material in the first opening, and at least one first interconnection trace electrical conducting material connected to the first electrical conducting material. A stiffening shank material is located adjacent the first dielectric material, the first electrical conducting material, and the first interconnection trace electrical conducting material.
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Refractory overactive bladder: Beyond oral anticholinergic therapy
Glinski, Ronald W.; Siegel, Steven
2007-01-01
Objectives: In this review, we discuss the treatment of refractory overactive bladder (OAB) that has not adequately responded to medication therapy and we propose an appropriate care pathway to the treatment of OAB. We also attempt to address the cost of OAB treatments. Materials and Methods: A selective expert review of the current literature on the subject of refractory OAB using MEDLINE was performed and the data is summarized. We also review our experience in treating refractory OAB. The role and outcomes of various treatment options for refractory OAB are discussed and combined therapy with oral anticholinergics is explored. Emerging remedies including intravesical botulinum toxin injection and pudendal neuromodulation are also reviewed, along with conventional surgical options. Results: In general behavioral therapy, pelvic floor electrical stimulation, magnetic therapy and posterior tibial nerve stimulation (PTNS), have shown symptom decreases in 50-80% of patients with OAB. Depending on the study, combination therapy with oral anticholinergics seems to improve efficacy of behavioral therapy and PTNS in approximately 10-30%. In multicenter, long-term randomized controlled trials, sacral neuromodulation has been shown to improve symptoms of OAB and OAB incontinence in up to 80% of the patients treated. Studies involving emerging therapies such as pudendal serve stimulation suggest that there may be a 15-20% increase in efficacy over sacral neuromodulation, but long-term studies are not yet available. Another emerging therapy, botulinum toxin, is also showing similar success in reducing OAB symptoms in 80-90% of patients. Surgical approaches, such as bladder augmentation, are a last resort in the treatment of OAB and are rarely used at this point unless upper tract damage is a concern and all other treatment options have been exhausted. Conclusion: The vast majority of OAB patients can be managed successfully by behavioral options with or without anticholinergic medications. When those fail, neuromodulation or intravesical botulinum toxin therapies are successful alternatives for most of the remaining group. We encourage practitioners responsible for the care of OAB patients to gain experience with these options. More research is needed to assess the cost-effectiveness of various OAB treatments PMID:19675795
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Improved Rare-Earth Emitter Hollow Cathode
NASA Technical Reports Server (NTRS)
Goebel, Dan M.
2011-01-01
An improvement has been made to the design of the hollow cathode geometry that was created for the rare-earth electron emitter described in Compact Rare Earth Emitter Hollow Cathode (NPO-44923), NASA Tech Briefs, Vol. 34, No. 3 (March 2010), p. 52. The original interior assembly was made entirely of graphite in order to be compatible with the LaB6 material, which cannot be touched by metals during operation due to boron diffusion causing embrittlement issues in high-temperature refractory materials. Also, the graphite tube was difficult to machine and was subject to vibration-induced fracturing. This innovation replaces the graphite tube with one made out of refractory metal that is relatively easy to manufacture. The cathode support tube is made of molybdenum or molybdenum-rhenium. This material is easily gun-bored to near the tolerances required, and finish machined with steps at each end that capture the orifice plate and the mounting flange. This provides the manufacturability and robustness needed for flight applications, and eliminates the need for expensive e-beam welding used in prior cathodes. The LaB6 insert is protected from direct contact with the refractory metal tube by thin, graphite sleeves in a cup-arrangement around the ends of the insert. The sleeves, insert, and orifice plate are held in place by a ceramic spacer and tungsten spring inserted inside the tube. To heat the cathode, an insulating tube is slipped around the refractory metal hollow tube, which can be made of high-temperature materials like boron nitride or aluminum nitride. A screw-shaped slot, or series of slots, is machined in the outside of the ceramic tube to constrain a refractory metal wire wound inside the slot that is used as the heater. The screw slot can hold a single heater wire that is then connected to the front of the cathode tube by tack-welding to complete the electrical circuit, or it can be a double slot that takes a bifilar wound heater with both leads coming out the back. This configuration replaces the previous sheathed heater design that limited the cycling-life of the cathode.
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Colin, J J; Diot, Y; Guerin, Ph; Lamongie, B; Berneau, F; Michel, A; Jaouen, C; Abadias, G
2016-02-01
An experimental setup designed for in situ electrical resistance measurement during thin film growth is described. The custom-built sample holder with a four-point probe arrangement can be loaded into a high-vacuum magnetron sputter-deposition chamber through a load-lock transfer system, allowing measurements on series of samples without venting the main chamber. Electrical contact is ensured with circular copper tracks inserted in a Teflon plate on a mounting holder station inside the deposition chamber. This configuration creates the possibility to measure thickness-dependent electrical resistance changes with sub-monolayer resolution and is compatible with use of sample rotation during growth. Examples are presented for metallic films with high adatom mobility growing in a Volmer-Weber mode (Ag and Pd) as well as for refractory metal (Mo) with low adatom mobility. Evidence for an amorphous-to-crystalline phase transition at a film thickness of 2.6 nm is reported during growth of Mo on an amorphous Si underlayer, supporting previous findings based on in situ wafer curvature measurements.
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2018-03-20
B-Cell Prolymphocytic Leukemia; Recurrent Chronic Lymphocytic Leukemia; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Follicular Lymphoma; Recurrent Lymphoplasmacytic Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Non-Hodgkin Lymphoma; Recurrent Small Lymphocytic Lymphoma; Refractory Chronic Lymphocytic Leukemia; Refractory Diffuse Large B-Cell Lymphoma; Refractory Follicular Lymphoma; Refractory Lymphoplasmacytic Lymphoma; Refractory Mantle Cell Lymphoma; Refractory Marginal Zone Lymphoma; Refractory Non-Hodgkin Lymphoma; Refractory Small Lymphocytic Lymphoma; Richter Syndrome
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Apparatus for detecting alpha radiation in difficult access areas
Steadman, Peter; MacArthur, Duncan W.
1997-09-02
An electrostatic alpha radiation detector for measuring alpha radiation emitted from inside an enclosure comprising an electrically conductive expandable electrode for insertion into the enclosure. After insertion, the electrically conductive expandable electrode is insulated from the enclosure and defines a decay cavity between the electrically conductive expandable electrode and the enclosure so that air ions generated in the decay cavity are electrostatically captured by the electrically conductive expandable electrode and the enclosure when an electric potential is applied between the electrically conductive expandable electrode and the enclosure. Indicator means are attached to the electrically conductive expandable electrode for indicating an electrical current produced by generation of the air ions generated in the decay cavity by collisions between air molecules and the alpha particles emitted from the enclosure. A voltage source is connected between the indicator means and the electrically conductive enclosure for creating an electric field between the electrically conductive expandable electrode and the enclosure.
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Abemaciclib in Children With DIPG or Recurrent/Refractory Solid Tumors
2017-07-14
Diffuse Intrinsic Pontine Glioma; Brain Tumor, Recurrent; Solid Tumor, Recurrent; Neuroblastoma, Recurrent, Refractory; Ewing Sarcoma, Recurrent, Refractory; Rhabdomyosarcoma, Recurrent, Refractory; Osteosarcoma, Recurrent, Refractory; Rhabdoid Tumor, Recurrent, Refractory
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Geant4 calculations for space radiation shielding material Al2O3
NASA Astrophysics Data System (ADS)
Capali, Veli; Acar Yesil, Tolga; Kaya, Gokhan; Kaplan, Abdullah; Yavuz, Mustafa; Tilki, Tahir
2015-07-01
Aluminium Oxide, Al2O3 is the most widely used material in the engineering applications. It is significant aluminium metal, because of its hardness and as a refractory material owing to its high melting point. This material has several engineering applications in diverse fields such as, ballistic armour systems, wear components, electrical and electronic substrates, automotive parts, components for electric industry and aero-engine. As well, it is used as a dosimeter for radiation protection and therapy applications for its optically stimulated luminescence properties. In this study, stopping powers and penetrating distances have been calculated for the alpha, proton, electron and gamma particles in space radiation shielding material Al2O3 for incident energies 1 keV - 1 GeV using GEANT4 calculation code.
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Electric energy production by particle thermionic-thermoelectric power generators
NASA Technical Reports Server (NTRS)
Oettinger, P. E.
1980-01-01
Thermionic-thermoelectric power generators, composed of a thin layer of porous, low work function material separating a heated emitter electrode and a cooler collector electrode, have extremely large Seebeck coefficients of over 2 mV/K and can provide significant output power. Preliminary experiments with 20-micron thick (Ba Sr Ca)O coatings, limited by evaporative loss to temperatures below 1400 K, have yielded short circuit current densities of 500 mA/sq cm and power densities of 60 mW/ sq cm. Substantially more output is expected with cesium-coated refractory oxide particle coatings operating at higher temperatures. Practical generators will have thermal-to-electrical efficiencies of 10 to 20%. Further increases can be gained by cascading these high-temperature devices with lower temperature conventional thermoelectric generators.
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Lengline, Etienne; Drenou, Bernard; Peterlin, Pierre; Tournilhac, Olivier; Abraham, Julie; Berceanu, Ana; Dupriez, Brigitte; Guillerm, Gaelle; Raffoux, Emmanuel; de Fontbrune, Flore Sicre; Ades, Lionel; Balsat, Marie; Chaoui, Driss; Coppo, Paul; Corm, Selim; Leblanc, Thierry; Maillard, Natacha; Terriou, Louis; Socié, Gerard; de Latour, Regis Peffault
2018-02-01
Few therapeutic options are available for patients with aplastic anemia who are ineligible for transplantation or refractory to immunosuppressive therapy. Eltrombopag was recently shown to produce trilineage responses in refractory patients. However, the effects of real-life use of this drug remain unknown. This retrospective study (2012-2016) was conducted by the French Reference Center for Aplastic Anemia on patients with relapsed/refractory aplastic anemia, and patients ineligible for antithymocyte globulin or transplantation, who received eltrombopag for at least 2 months. Forty-six patients with aplastic anemia were given eltrombopag without prior antithymocyte globulin treatment (n=11) or after antithymocyte globulin administration (n=35) in a relapsed/refractory setting. Eltrombopag (median daily dose 150 mg) was introduced 17 months (range, 8-50) after the diagnosis of aplastic anemia. At last followup, 49% were still receiving treatment, 9% had stopped due to a robust response, 2% due to toxicity and 40% due to eltrombopag failure. Before eltrombopag treatment, all patients received regular transfusions. The overall rates of red blood cell and platelet transfusion independence were 7%, 33%, 46% and 46% at 1, 3, 6 months and last follow-up. Responses were slower to develop in antithymocyte treatment-naïve patients. In patients achieving transfusion independence, hemoglobin concentration and platelet counts improved by 3 g/dL (interquartile range, 1.4-4.5) and 42×10 9 /L (interquartile range, 11-100), respectively. Response in at least one lineage (according to National Institutes of Health criteria) was observed in 64% of antithymocyte treatment-naïve and 74% of relapsed/refractory patients, while trilineage improvement was observed in 27% and 34%, respectively. We found high rates of hematologic improvement and transfusion independence in refractory aplastic anemia patients but also in patients ineligible for antithymocyte globulin receiving first-line treatment. In conclusion, elderly patients unfit for antithymocyte globulin therapy may benefit from eltrombopag. Copyright© 2018 Ferrata Storti Foundation.
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Nowacki, Andreas; Seidel, Kathleen; Schucht, Philippe; Schindler, Kaspar; Abela, Eugenio; Heinemann, Dorothea; Gutbrod, Klemens; Wiest, Roland; Raabe, Andreas; Pollo, Claudio
2015-08-01
A case is presented and a systematic review of the literature is provided to update our current knowledge of induction of fear by cortical stimulation. We present a case of refractory epilepsy associated with a lesion where fear could be induced by intraoperative electrical stimulation of the posterior inner part of the superior temporal gyrus. We performed a systematic review of the literature using PubMed with the key words "epilepsy AND emotion", "cortical stimulation AND emotion," and "human brain stimulation AND behavior". Intraoperative cortical stimulation of the inner part of the posterior superior temporal gyrus reliably induced fear and progressive screaming behavior. Stimulation through subdural grid electrodes did not induce this phenomenon. A systematic review of the literature identified fear induction by stimulation of different widespread cortical areas including the temporal pole, the insula, and the anterior cingulate cortex. The posterior part of the superior temporal gyrus has so far not been associated with fear induction after electrical stimulation. Although our observation suggests that this area of the brain could be part of a network involved in the elicitation of fear, dysfunction of this network induced by epilepsy could also explain the observed phenomenon. Electrophysiologic and imaging studies must be conducted to improve our understanding of the cortical networks forming the neuroanatomical substrate of higher brain functions and experiences such as fear. Copyright © 2015 Elsevier Inc. All rights reserved.
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Tolone, Salvatore; Savarino, Edoardo; Docimo, Ludovico
2015-10-01
Radiofrequency catheter ablation (RFCA) is a potentially curative method for treatment of highly symptomatic and drug-refractory atrial fibrillation (AF). However, this technique can provoke esophageal and nerve lesion, due to thermal injury. To our knowledge, there have been no reported cases of a newly described motor disorder, the Jackhammer esophagus (JE) after RFCA, independently of GERD. We report a case of JE diagnosed by high-resolution manometry (HRM), in whom esophageal symptoms developed 2 weeks after RFCA, in absence of objective evidence of GERD. A 65-year-old male with highly symptomatic, drug-refractory paroxysmal AF was candidate to complete electrical pulmonary vein isolation with RFCA. Prior the procedure, the patient underwent HRM and impedance-pH to rule out GERD or hiatal hernia presence. All HRM parameters, according to Chicago classification, were within normal limits. No significant gastroesophageal reflux was documented at impedance pH monitoring. Patient underwent RFCA with electrical disconnection of pulmonary vein. After two weeks, patient started to complain of dysphagia for solids, with acute chest-pain. The patient repeated HRM and impedance-pH monitoring 8 weeks after RFCA. HRM showed in all liquid swallows the typical spastic hypercontractile contractions consistent with the diagnosis of JE, whereas impedance-pH monitoring resulted again negative for GERD. Esophageal dysmotility can represent a possible complication of RFCA for AF, probably due to a vagal nerve injury, and dysphagia appearance after this procedure must be timely investigated by HRM.
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Marchant, David D.; Killpatrick, Don H.
1978-01-01
An electrode capable of withstanding high temperatures and suitable for use as a current collector in the channel of a magnetohydrodynamic (MHD) generator consists of a sintered powdered metal base portion, the upper surface of the base being coated with a first layer of nickel aluminide, an intermediate layer of a mixture of nickel aluminide - refractory ceramic on the first layer and a third or outer layer of a refractory ceramic material on the intermediate layer. The sintered powdered metal base resists spalling by the ceramic coatings and permits greater electrode compliance to thermal shock. The density of the powdered metal base can be varied to allow optimization of the thermal conductivity of the electrode and prevent excess heat loss from the channel.
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Low resistance thin film organic solar cell electrodes
Forrest, Stephen [Princeton, NJ; Xue, Jiangeng [Piscataway, NJ
2008-01-01
A method which lower the series resistance of photosensitive devices includes providing a transparent film of a first electrically conductive material arranged on a transparent substrate; depositing and patterning a mask over the first electrically conductive material, such that openings in the mask have sloping sides which narrow approaching the substrate; depositing a second electrically conductive material directly onto the first electrically conductive material exposed in the openings of the mask, at least partially filling the openings; stripping the mask, leaving behind reentrant structures of the second electrically conductive material which were formed by the deposits in the openings of the mask; after stripping the mask, depositing a first organic material onto the first electrically conductive material in between the reentrant structures; and directionally depositing a third electrically conductive material over the first organic material deposited in between the reentrant structures, edges of the reentrant structures aligning deposition so that the third electrically conductive material does not directly contact the first electrically conductive material, and does not directly contact the second electrically conductive material.
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Flexible neural interfaces with integrated stiffening shank
Tooker, Angela C.; Felix, Sarah H.; Pannu, Satinderpall S.; Shah, Kedar G.; Sheth, Heeral; Tolosa, Vanessa
2016-07-26
A neural interface includes a first dielectric material having at least one first opening for a first electrical conducting material, a first electrical conducting material in the first opening, and at least one first interconnection trace electrical conducting material connected to the first electrical conducting material. A stiffening shank material is located adjacent the first dielectric material, the first electrical conducting material, and the first interconnection trace electrical conducting material.
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Osadchii, Oleg E
2017-01-01
Na+ channel blockers flecainide and quinidine can increase propensity to ventricular tachyarrhythmia, whereas lidocaine and mexiletine are recognized as safe antiarrhythmics. Clinically, ventricular fibrillation is often precipitated by transient tachycardia that reduces action potential duration, suggesting that a critical shortening of the excitation wavelength (EW) may contribute to the arrhythmic substrate. This study examined whether different INa blockers can produce contrasting effects on the rate adaptation of the EW, which would explain the difference in their safety profile. In perfused guinea-pig hearts, effective refractory periods (ERP), conduction times, and EW values were determined over a wide range of cardiac pacing intervals. All INa blockers tested were found to flatten the slope of ERP restitution, indicating antiarrhythmic tendency. However, with flecainide and quinidine, the beneficial changes in ERP were reversed owing to the use-dependent conduction slowing, thereby leading to significantly steepened restitution of the EW. In contrast, lidocaine and mexiletine had no effect on ventricular conduction, and therefore reduced the slope of the EW restitution, as expected from their effect on ERP. These findings suggest that the slope of the EW restitution is an important electrophysiological determinant which can discriminate INa blockers with proarrhythmic and antiarrhythmic profile.
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NASA Technical Reports Server (NTRS)
Andrews, Russell J.
2003-01-01
Three examples of neuroprotective applications of electrical stimulation-neuromodulation-are considered: (1) the diagnosis and treatment of epilepsy, (2) the augmentation of peripheral nerve regeneration after transection, and (3) the interaction between electrical stimulation and neurotrophins (notably brain derived neurotrophic factor [BDNF]) in various neuroprotective situations. The research cited demonstrates clear benefit from appropriate electrical stimulation in the treatment of (1) certain patients with medication-refractory epilepsy, and (2) the functional regeneration of peripheral nerves after transection and surgical repair. Furthermore, neuromodulation of peripheral nerve regeneration has been associated with an increase in the neurotrophin BDNF. The roles of BDNF and other neurotrophins in several disorders of the nervous system are discussed in the context of neuromodulation and its augmentation of neurotrophins. Neuromodulation-at least in part through its effect on BDNF and other neurotrophins-will likely play a major role in the treatment (and possibly prevention) of disorders of the nervous system for which neuroproteive pharmacologic agents have traditionally been sought.
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SP-100 multimegawatt scaleup to meet electric propulsion mission requirements
NASA Astrophysics Data System (ADS)
Newkirk, D. W.; Salamah, S. A.; Stewart, S. L.; Pluta, P. R.
The SP-100 nuclear heat source technology, utilizing uranium nitride fuel clad in PWC-11 in a fast reactor with lithium coolant circulated by an electromagnetic pump, is shown to be directly extrapolatable to thermal power levels that meet NASA nuclear electric propulsion requirements using different power conversion techniques. The SP-100 nuclear technology can be applied to missions with NEP (nuclear electric propulsion) requirements as low as tens of kWe to tens of MWe. It is pointed out that the SP-100 heat source has a great advantage of very long lifetime capability, since it utilizes very rugged refractory metal fuel pins and is independent of the power conversion scheme chosen for a given mission. The only moving parts in the nuclear subsystems are the control rods moved to compensate for fuel enrichment degradation due to fission and for power shutdown. Lowest alpha values in the range of interest for potential NASA missions are predicted for the dynamic Rankine and static HYTEC conversion systems.
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Andrews, Russell J
2003-05-01
Three examples of neuroprotective applications of electrical stimulation-neuromodulation-are considered: (1) the diagnosis and treatment of epilepsy, (2) the augmentation of peripheral nerve regeneration after transection, and (3) the interaction between electrical stimulation and neurotrophins (notably brain derived neurotrophic factor [BDNF]) in various neuroprotective situations. The research cited demonstrates clear benefit from appropriate electrical stimulation in the treatment of (1) certain patients with medication-refractory epilepsy, and (2) the functional regeneration of peripheral nerves after transection and surgical repair. Furthermore, neuromodulation of peripheral nerve regeneration has been associated with an increase in the neurotrophin BDNF. The roles of BDNF and other neurotrophins in several disorders of the nervous system are discussed in the context of neuromodulation and its augmentation of neurotrophins. Neuromodulation-at least in part through its effect on BDNF and other neurotrophins-will likely play a major role in the treatment (and possibly prevention) of disorders of the nervous system for which neuroproteive pharmacologic agents have traditionally been sought.
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Apparatus for detecting alpha radiation in difficult access areas
Steadman, P.; MacArthur, D.W.
1997-09-02
An electrostatic alpha radiation detector for measuring alpha radiation emitted from inside an enclosure comprising an electrically conductive expandable electrode for insertion into the enclosure is disclosed. After insertion, the electrically conductive expandable electrode is insulated from the enclosure and defines a decay cavity between the electrically conductive expandable electrode and the enclosure so that air ions generated in the decay cavity are electrostatically captured by the electrically conductive expandable electrode and the enclosure when an electric potential is applied between the electrically conductive expandable electrode and the enclosure. Indicator means are attached to the electrically conductive expandable electrode for indicating an electrical current produced by generation of the air ions generated in the decay cavity by collisions between air molecules and the alpha particles emitted from the enclosure. A voltage source is connected between the indicator means and the electrically conductive enclosure for creating an electric field between the electrically conductive expandable electrode and the enclosure. 4 figs.
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Antiarrhythmic properties of atrial pacing.
Kliś, Magdalena; Sławuta, Agnieszka; Gajek, Jacek
2017-01-01
Bradycardia, atrial stretch and dilatation, autonomic nervous system disorders, and the presence of triggers such as atrial premature contractions, are factors which predispose a person to paroxysmal AF. Atrial pacing not only eliminates bradycardia but also prevents atrial premature contractions and dispersion of refractoriness, which are a substrate for atrial fibrillation. As the prolonged duration of atrial activation during pacing, especially from locations changing the physiological pattern of this activation (right atrium lateral wall, right atrium appendage), negatively influences both a mechanical and an electrical function of the atria, the atrial pacing site affects an atrial arrhythmogenesis. A conventional atrial lead location in the right atrium appendage causes non-physiological activation propagation, resulting in a prolongation of the activation time of both atria. This location is optimal according to a passive fixation of the atrial lead but the available contemporary active fixation leads could potentially be located in any area of the atrium. There is growing evidence of the benefit of pacing, imitating the physiological propagation of impulses within the atria. It seems that the Bachmann's bundle pacing is the best pacing site within the atria, not only positively influencing the atrial mechanical function but also best fulfilling the so-called atrial resynchronization function, in particular in patients with interatrial conduction delay. It can be effectively achieved using only one atrial electrode, and the slight shortening of atrioventricular conduction provides an additional benefit of this atrial pacing site.
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2018-06-18
Refractory Diffuse Large B Cell Lymphoma; Refractory Primary Mediastinal B Cell Lymphoma; Refractory Transformed Follicular Lymphoma; Relapsed/Refractory Transplant Ineligible Diffuse Large B Cell Lymphoma; Relapsed/Refractory Transplant Ineligible Primary Mediastinal B Cell Lymphoma; Relapsed/Refractory Transplant Ineligible Transformed Follicular Lymphoma; Relapsed/Refractory Large B Cell Lymphoma Including DLBCL, PMBCL, TFL and HGBCL After Two Systemic Lines of Therapy" in Phase 2 Expanded Cohorts
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Valles-Antuña, C; Pérez-Haro, M L; González-Ruiz de L, C; Quintás-Blanco, A; Tamargo-Diaz, E M; García-Rodríguez, J; San Martín-Blanco, A; Fernandez-Gomez, J M
2017-09-01
To assess the efficacy of treatment with transcutaneous posterior tibial nerve stimulation (TPTNS) in patients with urge urinary incontinence, of neurogenic or nonneurogenic origin, refractory to first-line therapeutic options. We included 65 patients with urge urinary incontinence refractory to medical treatment. A case history review, a urodynamic study and a somatosensory evoked potentials (SEP) study were conducted before the TPTNS, studying the functional urological condition by means of a voiding diary. The treatment consisted of 10 weekly sessions of TPTNS lasting 30minutes. Some 57.7% of the patients showed abnormal tibial SEPs, and 42% showed abnormal pudendal SEPs. A statistically significant symptomatic improvement was observed in all clinical parameters after treatment with TPTNS, and 66% of the patients showed an overall improvement, regardless of sex, the presence of underlying neurological disorders, detrusor hyperactivity in the urodynamic study or SEP disorders. There were no adverse effects during the treatment. TPTNS is an effective and well tolerated treatment in patients with urge incontinence refractory to first-line therapies and should be offered early in the treatment strategy. New studies are needed to identify the optimal parameters of stimulation, the most effective treatment protocols and long-term efficacy, as well as its applicability to patients with a neurogenic substrate. Copyright © 2017 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.
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Bekheit, Mohamed; Baddour, Nahed; Katri, Khaled; Taher, Yousry; El Tobgy, Khaled; Mousa, Essam
2016-01-01
Background Hyperbaric oxygen (HBO) is used as part of treatment in a variety of clinical conditions. Its use in the treatment of ulcerative colitis has been reported in few clinical reports. Objective We report the effect of HBO on refractory ulcerative colitis exploring one potential mechanism of action. Design A review of records of patients with refractory ulcerative colitis who received HBO was conducted. Clinical and histopathological scoring was utilised to evaluate the response to HBO therapy (HBOT). Results All patients manifested clinical improvement by the 40th cycle of HBOT. The median number of stool frequency dropped from seven motions/day (range=3–20) to 1/day (range=0.5–3), which was significant (z=−4.6, p<0.001). None of the patients manifested persistent blood passage after HBOT (z=−3.2, p=0.002). The severity index significantly improved after HBOT (z=−4.97, p<0.001). Histologically, a significant reduction of the scores of activity was recorded accompanied by a significant increase in the proliferating cell nuclear antigen labelling index of the CD44 cells of the colonic mucosa (p=0.001). Conclusions HBOT is effective in the setting of refractory ulcerative colitis. The described protocol is necessary for successful treatment. HBOT stimulates colonic stem cells to promote healing. PMID:27195128
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Danion, F; Rosine, N; Belkhir, R; Gottenberg, J E; Hachulla, E; Chatelus, E; Pugnet, G; Pers, Y M; Mariette, X; Sibilia, J; Seror, R
2016-11-01
Objective The objective of this study was to assess the safety and efficacy of abatacept in patients with SLE refractory to conventional treatment in routine clinical practice. Methods This retrospective study included 11 SLE patients treated with abatacept for an active and refractory disease. The primary endpoint was the change in SLE Disease Activity Index (SLEDAI) score at six months. Response was defined as a decrease of SLEDAI ≥4 in a patient continuing abatacept. Results Indications of abatacept treatment were articular ( n=8), renal ( n=1) and cutaneous ( n=1) involvement and autoimmune thrombocytopenia ( n=1). Abatacept was discontinued before six months in two patients, because of adverse event ( n=1) and/or lupus flare ( n=2). The median SLEDAI decreased from 6 (2-20) to 4 (0-20) ( p=0.031). Decrease of SLEDAI ≥4 was observed in 6/11 patients (55%) and response to treatment according to the physician's judgement in 8/11 (73%) patients. Improvement of articular involvement was observed in 7/8 (87.5%) patients. Four adverse events were observed in three patients, but no severe infection occurred. Conclusion This study suggests some efficacy of abatacept in patients with refractory disease in routine clinical practice, particularly in the case of articular manifestations, with an acceptable safety profile. These data support conducting new controlled trials of abatacept in SLE patients.
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Williams, Brent A.; Law, Arjun Datt; Routy, Bertrand; denHollander, Neal; Gupta, Vikas; Wang, Xing-Hua; Chaboureau, Amélie; Viswanathan, Sowmya; Keating, Armand
2017-01-01
Background Autologous NK cell therapy can treat a variety of malignancies, but is limited by patient-specific variations in potency and cell number expansion. In contrast, allogeneic NK cell lines can overcome many of these limitations. Cells from the permanent NK-92 line are constitutively activated, lack inhibitory receptors and appear to be safe based on two prior phase I trials. Materials and Methods We conducted a single-center, non-randomized, non-blinded, open-label, Phase I dose-escalation trial of irradiated NK-92 cells in adults with refractory hematological malignancies who relapsed after autologous hematopoietic cell transplantation (AHCT). The objectives were to determine safety, feasibility and evidence of activity. Patients were treated at one of three dose levels (1 × 109 cells/m2, 3 × 109 cells/m2 and 5 × 109 cells/m2), given on day 1, 3 and 5 for a planned total of six monthly cycles. Results Twelve patients with lymphoma or multiple myeloma who relapsed after AHCT for relapsed/refractory disease were enrolled in this trial. The treatment was well tolerated, with minor toxicities restricted to acute infusional events, including fever, chills, nausea and fatigue. Two patients achieved a complete response (Hodgkin lymphoma and multiple myeloma), two patients had minor responses and one had clinical improvement on the trial. Conclusions Irradiated NK-92 cells can be administered at very high doses with minimal toxicity in patients with refractory blood cancers, who had relapsed after AHCT. We conclude that high dose NK-92 therapy is safe, shows some evidence of efficacy in patients with refractory blood cancers and warrants further clinical investigation. PMID:29179517
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The effects of classic ketogenic diet on serum lipid profile in children with refractory seizures.
Zamani, Gholam Reza; Mohammadi, Mahmoud; Ashrafi, Mahmoud Reza; Karimi, Parviz; Mahmoudi, Maryam; Badv, Reza Shervin; Tavassoli, Ali Reza; Azizi Malamiri, Reza
2016-12-01
More than 25 % of children with epilepsy develop refractory seizures unresponsive to both old and new generation anticonvulsants. Since such seizures have a serious negative impact on the quality of life, other treatment options are considered. The ketogenic diet is a well-known treatment for managing refractory seizures, although its mechanism of action is unknown. Studies have shown that this diet is as good as, or better than, any of the newer medications in reducing seizure frequency. However, concerns about adverse effects have been raised. We conducted an open label trial to show the effects of this diet on serum lipid profile. Thirty-three children with refractory epilepsy were treated with the ketogenic diet and were followed for 6 months. Their serum lipid profile was assessed at baseline, and at 3 and 6 months after initiating the diet. Seizure frequency was reduced in 63 % of children (no seizures in 2/33 and reduced >50 % in 19/33). However, after 6 months of administering the diet, median triglyceride was significantly increased (from 84 to 180 mg/dl, P < 0.001), median total cholesterol was significantly increased (from 180 to 285 mg/dl, P < 0.001), median serum low-density lipoprotein (LDL) was significantly increased (from 91 to 175 mg/dl, P < 0.001), and median serum high-density lipoprotein (HDL) was significantly increased (from 51 to 58 mg/dl, P < 0.001). Results of this study indicate that a classic ketogenic diet in children with refractory seizures is effective in seizure reduction, but leads to development of hypercholesterolemia and hypertriglyceridemia.
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Shah, Manali R.; Khandekar, Rajiv B.; Zutshi, Rajiv; Mahrooqi, Rahima
2013-01-01
Background: We present outcomes of Ahmed Glaucoma Valve (AGV) implantation in treating refractory glaucoma in a tertiary hospital in Oman. Refractory glaucoma was defined as previously failed conventional glaucoma surgery and an uncontrolled intraocular pressure (IOP) of more than 21 mm Hg despite treatment with three topical and/or oral therapy. Materials and Methods: This historical cohort study was conducted in 2010. Details of medical and surgical treatment were recorded. Ophthalmologists examined eyes and performed glaucoma surgeries using AGV. The best corrected distant vision, IOP, and glaucoma medications were prospectively reviewed on 1st day, 1st, 6th, 12th week postoperatively, and at the last follow up. Result: Glaucoma specialists examined and treated 40 eyes with refractory glaucoma of 39 patients (20 males + 19 females). Neo-vascular glaucoma was present in 23 eyes. Vision before surgery was <3/60 in 21 eyes. At 12 weeks, one eye had vision better than 6/12, seven eyes had vision 6/18 to 6/60, and eight eyes had vision 6/60 to 3/60. Mean IOP was reduced from 42.9 (SD 16) to 14.2 (SD 8) and 19.1 (SD 7.8) mmHg at one and 12 weeks after surgery, respectively. At 12 weeks, five (12.5%) eyes had IOP controlled without medication. In 33 (77.5%) eyes, pressure was controlled by using one or two eye drops. The mean number of preoperative anti-glaucoma medications (2.38; SD 1.1) was reduced compared to the mean number of postoperative medications (1.92; SD 0.9) at 12 weeks. Conclusion: We succeeded in reducing visual disabilities and the number of anti-glaucoma medications used to treat refractory glaucoma by AGV surgery. PMID:23772122
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Xu, Yunyun; Zhong, Yi; Zhao, Minjing; Tu, Liudan; Fan, Meida; Zhang, Pingping; Wei, Qiujing; Cao, Shuangyan; Li, Qiuxia; Liao, Zetao; Lin, Zhiming; Pan, Yunfeng; Jin, Ou; Gu, Jieruo
2018-01-01
To evaluate the clinical efficacy and safety in patients with refractory ankylosing spondylitis (AS) initiating 99Tc-MDP therapy and explore the mechanisms. Refractory AS patients were enrolled in the clinical trial and received 99Tc-MDP treatments for 3 or 5 courses according to ASAS improvement. Efficacy and safety evaluations were conducted during the follow-up. 37 cytokines were quantified by Luminex at baseline and week 30. p-values<0.05 were considered statistically significant. 51 refractory AS patients were included, with 20 healthy people serving as the control group. The patients were in an active disease state (mean (SD) ASDAS 3.66 (0.83), BASDAI 4.53 (1.92)), 42(82.35%) patients had syndesmophytes. Their cytokines were significantly higher than that in the control group. After 3 courses of 99Tc-MDP treatment, 32 (62.75%) patients achieved ASAS20 improvement, 24 (47.06%) patients achieved a clinically significant improvement (ΔASDAS-CRP≥1.1). 27 patients entered the second stage to complete 5 courses of the treatment, all of whom achieved ASAS20 improvement, 18 (66.67%) patients achieved a clinically significant improvement. All clinical parameters including ASAS and ASDAS significantly improved as the treatment was continued. Cytokines also had significant down-regulation after the treatment, and the reductions had positive correlations with the improvements of disease activity. No serious adverse event was observed. This investigation confirmed the remarkable efficacy of 99Tc-MDP in a large number of refractory AS patients, and highlighted the mechanism by dramatic regulation on cytokines. 99Tc-MDP was safe in clinical application.
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Malempati, Suman; Weigel, Brenda; Ingle, Ashish M.; Ahern, Charlotte H.; Carroll, Julie M.; Roberts, Charles T.; Reid, Joel M.; Schmechel, Stephen; Voss, Stephan D.; Cho, Steven Y.; Chen, Helen X.; Krailo, Mark D.; Adamson, Peter C.; Blaney, Susan M.
2012-01-01
Purpose A phase I/II study of cixutumumab (IMC-A12) in children with refractory solid tumors was conducted. This study was designed to assess the toxicities, pharmacokinetics, and pharmacodynamics of cixutumumab in children to determine a recommended phase II dose and to assess antitumor activity in Ewing sarcoma (ES). Patients and Methods Pediatric patients with relapsed or refractory solid tumors were treated with cixutumumab as a 1-hour intravenous infusion once per week. Two dose levels—6 and 9 mg/kg—were evaluated using a standard three-plus-three cohort design. Patients with refractory ES were treated in an expanded phase II cohort at each dose level. Results Forty-seven eligible patients with a median age of 15 years (range, 4 to 28 years) were enrolled. Twelve patients were treated in the dose-finding phase. Hematologic and nonhematologic toxicities were generally mild and infrequent. Dose-limiting toxicities included grade 4 thrombocytopenia at 6 mg/kg and grade 3 dehydration at 9 mg/kg. Mean trough concentration (± standard deviation) at 9 mg/kg was 106 ± 57 μg/mL, which exceeded the effective trough concentration of 60 μg/mL observed in xenograft models. Three patients with ES had confirmed partial responses: one of 10 at 6 mg/kg and two of 20 at 9 mg/kg. Serum insulin-like growth factor I (IGF-I) levels consistently increased after one dose of cixutumumab. Tumor IGF-I receptor expression by immunohistochemistry did not correlate with response in patients with ES. Conclusion Cixutumumab is well tolerated in children with refractory solid tumors. The recommended phase II dose is 9 mg/kg. Limited single-agent activity of cixutumumab was seen in ES. PMID:22184397
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Vagus nerve stimulation therapy in partial epilepsy: a review.
Panebianco, Mariangela; Zavanone, Chiara; Dupont, Sophie; Restivo, Domenico A; Pavone, Antonino
2016-09-01
Epilepsy is a chronic neurological disorder characterized by recurrent, unprovoked epileptic seizures. The majority of people given a diagnosis of epilepsy have a good prognosis, but 20-30 % will develop drug-resistant epilepsy. Vagus nerve stimulation (VNS) is a neuromodulatory treatment that is used as an adjunctive therapy for treating people with medically refractory epilepsy. It consists of chronic intermittent electrical stimulation of the vagus nerve, delivered by a programmable pulse generator (Neuro-Cybernetic Prosthesis). In 1997, the Food and Drug Administration approved VNS as adjunctive treatment for medically refractory partial-onset seizures in adults and adolescents. This article reviews the literature from 1988 to nowadays. We discuss thoroughly the anatomy and physiology of vagus nerve and the potential mechanisms of actions and clinical applications involved in VNS therapy, as well as the management, safety, tolerability and effectiveness of VNS therapy. VNS for partial seizures appears to be an effective and well tolerated treatment in adult and pediatric patients. People noted improvements in feelings of well-being, alertness, memory and thinking skills, as well as mood. The adverse effect profile is substantially different from the adverse effect profile associated with antiepileptic drugs, making VNS a potential alternative for patients with difficulty tolerating antiepileptic drug adverse effects. Despite the passing years and the advent of promising neuromodulation technologies, VNS remains an efficacy treatment for people with medically refractory epilepsy. Past and ongoing investigations in other indications have provided signals of the therapeutic potential in a wide variety of conditions.
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A review of recombinant factor VII for refractory bleeding in nonhemophilic trauma patients.
Barletta, Jeffrey F; Ahrens, Christine L; Tyburski, James G; Wilson, Robert F
2005-03-01
Recombinant factor VII (rFVII) is an attractive agent to control refractory, coagulopathic bleeding in patients following major surgery. The purpose of this review is to evaluate the published experiences of rFVII in adult, nonhemophilic, surgical and trauma patients. A computerized literature search was conducted to identify articles pertaining to rFVII use for refractory bleeding in adult, nonhemophilic, surgical patients. The selected articles were reviewed and the applicable data was analyzed. A total of 117 patients were found in 8 case series and 24 case reports. Overall, rFVII was effective in restoring hemostasis in 99/117 (85%) patients with 76/99 (77%) surviving to hospital discharge. In trauma patients, hemostasis was achieved in 20/26 (77%) patients and 17/20 (85%) survived. There were 5 (4%) thromboembolic events observed in the 117 cases and much disparity was noted with the initial dose. Severe acidosis affected the activity of rFVII. Recombinant factor VII is an effective therapeutic agent for achieving hemostasis in nonhemophilic surgical patients. Published clinical experiences, however, are limited to small case series and case reports.
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Martínez, Carmen; Solano, Carlos; Ferrá, Christelle; Sampol, Antonia; Valcárcel, David; Pérez-Simón, José Antonio
2009-05-01
We conducted a phase II trial to investigate the safety and efficacy of alemtuzumab in treating steroid-refractory acute graft-versus-host disease (aGVHD) grade II or higher after stem cell transplantation. Ten adult patients (6 with aGVHD grade III and 4 with aGVHD grade IV) were included in the study. Nine patients had gastrointestinal tract involvement, 7 had skin involvement, and 5 had liver involvement. Five patients responded to treatment, 2 with complete response and 3 with partial response. Eight infectious events (4 of grade 3-4) and 7 cytomegalovirus (CMV) reactivations were observed. Six patients had grade 3-4 cytopenia. All 10 patients died (7 resulting from aGVHD progression, 2 from severe infection, and 1 from to leukemia relapse), at a median of 40 days (range, 4 to 88 days) after alemtuzumab treatment. Overall, our findings suggest that steroid-refractory aGVHD may be improved by treatment with alemtuzumab, but that this treatment does not overcome the dismal prognosis of patients with severe aGVHD, demonstrating the need for alternative therapies to treat this complication.
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Improving the thermal and physical properties of fire clay refractory bricks by added magnesia
NASA Astrophysics Data System (ADS)
Ibrahim, Sarmad I.; Ali, Nahedh M.; Abood, Tamara W.
2018-05-01
In this study, the Local natural Iraqi rocks kaolin with the addition of different proportions of MgO along with its effects on the physical and thermal properties of the prepared refractories were investigated. kaolin/MgO mixture was milled and classified into various size fractions, the kaolin (less than 105 µm) and MgO (less than 50µm). The specimens were mixed from kaolin and MgO in range M1 (95+5)%, M2 (90+10) %, M3(85+15)% and M4(80+20)% respectively. The green specimens were shaped by the semi-dry method using a hydraulic press and a molding pressure of (5)Ton with addition of (9-12) %wt. of pva solution ratio. After molding and drying, the specimens were fired at (1100, 1200 and 1300)°C. Physical properties (density, porosity, Water Absorption) and thermal properties (thermal conductivity) were measured for all the prepared samples. The results showed that the porosity was increased and the density was decreased, such increase &decrease affected on to the thermal properties for refractory.
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Murray, M.M.; Wilfong, D.H.; Lomax, R.E.
1998-12-08
An electrical cable for connecting transient voltage surge suppressors to electrical power panels. A strip of electrically conductive foil defines a longitudinal axis, with a length of an electrical conductor electrically attached to the metallic foil along the longitudinal axis. The strip of electrically conductive foil and the length of an electrical conductor are covered by an insulating material. For impedance matching purposes, triangular sections can be removed from the ends of the electrically conductive foil at the time of installation. 6 figs.
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Method of Fault Detection and Rerouting
NASA Technical Reports Server (NTRS)
Gibson, Tracy L. (Inventor); Medelius, Pedro J. (Inventor); Lewis, Mark E. (Inventor)
2013-01-01
A system and method for detecting damage in an electrical wire, including delivering at least one test electrical signal to an outer electrically conductive material in a continuous or non-continuous layer covering an electrically insulative material layer that covers an electrically conductive wire core. Detecting the test electrical signals in the outer conductive material layer to obtain data that is processed to identify damage in the outer electrically conductive material layer.
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Himmel, Herbert M
2008-01-01
An increased sensitivity of the heart to catecholamines or cardiac sensitization is a recognized risk during acute human exposure to halogenated hydrocarbons used as solvents, foam-blowing or fire-extinguishing agents, refrigerants, and aerosol propellants. Although cardiac sensitization to such "industrial" halocarbons can result in serious arrhythmia and death, research into its mechanistic basis has been limited, whereas the literature on volatile anesthetics (e.g., halothane, chloroform) is comparably extensive. A review of the literature on halocarbons and related volatile anesthetics was conducted. The available experimental evidence suggests that volatile anesthetics at physiologically relevant concentrations interact predominantly with the main repolarizing cardiac potassium channels hERG and I(Ks), as well as with calcium and sodium channels at slightly higher concentrations. On the level of the heart, inhibition of these ion channels is prone to alter both action potential shape (triangulation) and electrical impulse conduction, which may facilitate arrhythmogenesis by volatile anesthetics per se and is potentiated by catecholamines. Action potential triangulation by regionally heterogeneous inhibition of calcium and potassium channels will facilitate catecholamine-induced afterdepolarizations, triggered activity, and enhanced automaticity. Inhibition of cardiac sodium channels will reduce conduction velocity and alter refractory period; this is potentiated by catecholamines and promotes reentry arrhythmias. Other cardiac and/or neuronal mechanisms might also contribute to arrhythmogenesis. The few scattered in vitro data available for halocarbons (e.g., FC-12, halon 1301, trichloroethylene) suggest inhibition of cardiac sodium (conduction), calcium and potassium channels (triangulation), extraneuronal catecholamine reuptake, and various neuronal ion channels. Therefore, it is hypothesized that halocarbons promote cardiac sensitization by similar mechanisms as volatile anesthetics. Experimental approaches for further investigation of these sensitization mechanisms by selected halocarbons are suggested.
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Nivolumab in Treating Patients With Relapsed or Refractory Peripheral T-cell Lymphoma
2018-04-27
Blastic Plasmacytoid Dendritic Cell Neoplasm; Hepatosplenic T-Cell Lymphoma; HTLV-1 Infection; NK-Cell Lymphoma, Unclassifiable; Primary Systemic Anaplastic Large Cell Lymphoma, ALK-Negative; Recurrent Adult T-Cell Leukemia/Lymphoma; Recurrent Anaplastic Large Cell Lymphoma; Recurrent Angioimmunoblastic T-cell Lymphoma; Recurrent Enteropathy-Associated T-Cell Lymphoma; Recurrent Mycosis Fungoides; Refractory Adult T-Cell Leukemia/Lymphoma; Refractory Anaplastic Large Cell Lymphoma; Refractory Angioimmunoblastic T-cell Lymphoma; Refractory Enteropathy-Associated T-Cell Lymphoma; Refractory Mycosis Fungoides; Refractory Nasal Type Extranodal NK/T-Cell Lymphoma; Refractory Peripheral T-Cell Lymphoma, Not Otherwise Specified
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2018-03-12
Previously Treated Myelodysplastic Syndrome; Recurrent Adult Acute Myeloid Leukemia; Recurrent Anaplastic Large Cell Lymphoma; Recurrent Angioimmunoblastic T-cell Lymphoma; Recurrent Cutaneous T-Cell Non-Hodgkin Lymphoma; Recurrent Mycosis Fungoides; Recurrent Plasma Cell Myeloma; Recurrent T-Cell Non-Hodgkin Lymphoma; Refractory Anaplastic Large Cell Lymphoma; Refractory Angioimmunoblastic T-cell Lymphoma; Refractory Cutaneous T-Cell Non-Hodgkin Lymphoma; Refractory Mycosis Fungoides; Refractory Peripheral T-Cell Lymphoma, Not Otherwise Specified; Refractory Plasma Cell Myeloma; Refractory T-Cell Non-Hodgkin Lymphoma
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Alisertib and Romidepsin in Treating Patients With Relapsed or Refractory B-Cell or T-Cell Lymphomas
2018-05-02
High Grade B-Cell Lymphoma With MYC and BCL2 or BCL6 Rearrangements; MYC Positive; Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Burkitt Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Follicular Lymphoma; Recurrent Hodgkin Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Mature T- and NK-Cell Non-Hodgkin Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Burkitt Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Follicular Lymphoma; Refractory Hodgkin Lymphoma; Refractory Mantle Cell Lymphoma; Refractory Mature T-Cell and NK-Cell Non-Hodgkin Lymphoma
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Cannan, Chad; Bartel, Lewis; Palisch, Terrence; Aldridge, David
2015-01-13
Electrically conductive proppants and methods for detecting, locating, and characterizing same are provided. The electrically conductive proppant can include a substantially uniform coating of an electrically conductive material having a thickness of at least 500 nm. The method can include injecting a hydraulic fluid into a wellbore extending into a subterranean formation at a rate and pressure sufficient to open a fracture therein, injecting into the fracture a fluid containing the electrically conductive proppant, electrically energizing the earth at or near the fracture, and measuring three dimensional (x, y, and z) components of electric and magnetic field responses at a surface of the earth or in an adjacent wellbore.
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NASA Astrophysics Data System (ADS)
Shibata, K.; Yoshida, K.; Daiguji, K.; Sato, H.; , T., Ii; Hirakawa, K.
2017-10-01
An electric-field control of quantized conductance in metal (gold) quantum point contacts (QPCs) is demonstrated by adopting a liquid-gated electric-double-layer (EDL) transistor geometry. Atomic-scale gold QPCs were fabricated by applying the feedback-controlled electrical break junction method to the gold nanojunction. The electric conductance in gold QPCs shows quantized conductance plateaus and step-wise increase/decrease by the conductance quantum, G0 = 2e2/h, as EDL-gate voltage is swept, demonstrating a modulation of the conductance of gold QPCs by EDL gating. The electric-field control of conductance in metal QPCs may open a way for their application to local charge sensing at room temperature.
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Electrical conductivity modeling in fractal non-saturated porous media
NASA Astrophysics Data System (ADS)
Wei, W.; Cai, J.; Hu, X.; Han, Q.
2016-12-01
The variety of electrical conductivity in non-saturated conditions is important to study electric conduction in natural sedimentary rocks. The electrical conductivity in completely saturated porous media is a porosity-function representing the complex connected behavior of single conducting phases (pore fluid). For partially saturated conditions, the electrical conductivity becomes even more complicated since the connectedness of pore. Archie's second law is an empirical electrical conductivity-porosity and -saturation model that has been used to predict the formation factor of non-saturated porous rock. However, the physical interpretation of its parameters, e.g., the cementation exponent m and the saturation exponent n, remains questionable. On basis of our previous work, we combine the pore-solid fractal (PSF) model to build an electrical conductivity model in non-saturated porous media. Our theoretical porosity- and saturation-dependent models contain endmember properties, such as fluid electrical conductivities, pore fractal dimension and tortuosity fractal dimension (representing the complex degree of electrical flowing path). We find the presented model with non-saturation-dependent electrical conductivity datasets indicate excellent match between theory and experiments. This means the value of pore fractal dimension and tortuosity fractal dimension change from medium to medium and depends not only on geometrical properties of pore structure but also characteristics of electrical current flowing in the non-saturated porous media.
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2017-10-24
CD19-Positive Neoplastic Cells Present; Recurrent Adult Acute Lymphoblastic Leukemia; Recurrent Chronic Lymphocytic Leukemia; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Non-Hodgkin Lymphoma; Recurrent Small Lymphocytic Lymphoma; Refractory Acute Lymphoblastic Leukemia; Refractory Chronic Lymphocytic Leukemia; Refractory Diffuse Large B-Cell Lymphoma; Refractory Mantle Cell Lymphoma; Refractory Non-Hodgkin Lymphoma; Refractory Small Lymphocytic Lymphoma
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Shiroshita-Takeshita, Akiko; Sakabe, Masao; Haugan, Ketil; Hennan, James K; Nattel, Stanley
2007-01-23
Abnormal intercellular communication caused by connexin dysfunction may be involved in atrial fibrillation (AF). The present study assessed the effect of the gap junctional conduction-enhancing peptide rotigaptide on AF maintenance in substrates that result from congestive heart failure induced by 2-week ventricular tachypacing (240 bpm), atrial tachypacing (ATP; 400 bpm for 3 to 6 weeks), and isolated atrial myocardial ischemia. Electrophysiological study and epicardial mapping were performed before and after rotigaptide administration in dogs with ATP and congestive heart failure, as well as in similarly instrumented sham dogs that were not tachypaced. For atrial myocardial ischemia, dogs administered rotigaptide before myocardial ischemia were compared with no-drug myocardial ischemia controls. ATP significantly shortened the atrial effective refractory period (P=0.003) and increased AF duration (P=0.008), with AF lasting >3 hours in all 6-week ATP animals. Rotigaptide increased conduction velocity in ATP dogs slightly but significantly (P=0.04) and did not affect the effective refractory period, AF duration, or atrial vulnerability. In dogs with congestive heart failure, rotigaptide also slightly increased conduction velocity (P=0.046) but failed to prevent AF promotion. Rotigaptide had no statistically significant effects in sham dogs. Myocardial ischemia alone increased AF duration and impaired conduction (based on conduction velocity across the ischemic border and indices of conduction heterogeneity). Rotigaptide prevented myocardial ischemia-induced conduction slowing and AF duration increases. Rotigaptide improves conduction in various AF models but suppresses AF only for the acute ischemia substrate. These results define the atrial antiarrhythmic profile of a mechanistically novel antiarrhythmic drug and suggest that gap junction dysfunction may be more important in ischemic AF than in ATP remodeling or congestive heart failure substrates.
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NASA Astrophysics Data System (ADS)
Mosayebidorcheh, Taha; Hosseinibalam, Fahimeh; Hassanzadeh, Smaeyl
2017-11-01
In this paper, the effect of atmospheric electrical conductivity on the electromagnetic waves radiated by a vertical electric dipole located in the earth, near the surface of the earth, is investigated. As far as electrical conductivity is concerned, the atmosphere is divided into three areas, in which the electrical conductivity changes with altitude. The Maxwell equations in these areas are investigated as well. Using the differential transform method, the differential equation is solved in a way that atmospheric electrical conductivity is variable. Solving the problem in these areas indicates that electrical conductivity in the middle and lower areas of atmosphere may be ignored. However, in the upper areas of atmosphere, the magnitude of the magnetic field in the ionosphere at a frequency of 10 kHz at night is five times smaller when electrical conductivity is considered compared to when it is neglected.
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NASA Astrophysics Data System (ADS)
Connolly, Adam; Robson, Matthew D.; Schneider, Jürgen; Burton, Rebecca; Plank, Gernot; Bishop, Martin J.
2017-09-01
Novel low-energy defibrillation therapies are thought to be driven by virtual-electrodes (VEs), due to the interaction of applied monophasic electric shocks with fine-scale anatomical structures within the heart. Significant inter-species differences in the cardiac (micro)-anatomy exist, however, particularly with respect to the degree of endocardial trabeculations, which may underlie important differences in response to low-energy defibrillation protocols. Understanding the interaction of monophasic electric fields with the specific human micro-anatomy is therefore imperative in facilitating the translation and optimisation of these promising experimental therapies to the clinic. In this study, we sought to investigate how electric fields from implanted devices interact with the highly trabeculated human endocardial surface to better understand shock success in order to help optimise future clinical protocols. A bi-ventricular human computational model was constructed from high resolution (350 μm) ex-vivo MR data, including anatomically accurate endocardial structures. Monophasic shocks were applied between a basal right ventricular catheter and an exterior ground. Shocks of varying strengths were applied with both anodal [positive right ventricle (RV) electrode] and cathodal (negative RV electrode) polarities at different states of tissue refractoriness and during induced arrhythmias. Anodal shocks induced isolated positive VEs at the distal side of "detached" trabeculations, which rapidly spread into hyperpolarised tissue on the surrounding endocardial surfaces following the shock. Anodal shocks thus depolarised more tissue 10 ms after the shock than cathodal shocks where the propagation of activation from VEs induced on the proximal side of "detached" trabeculations was prevented due to refractory endocardium. Anodal shocks increased arrhythmia complexity more than cathodal shocks during failed anti-arrhythmia shocks. In conclusion, multiple detached trabeculations in the human ventricle interact with anodal stimuli to induce multiple secondary sources from VEs, facilitating more rapid shock-induced ventricular excitation compared to cathodal shocks. Such a mechanism may help explain inter-species differences in response to shocks and help to develop novel defibrillation strategies.
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McComsey, David F; Smith-Swintosky, Virginia L; Parker, Michael H; Brenneman, Douglas E; Malatynska, Ewa; White, H Steve; Klein, Brian D; Wilcox, Karen S; Milewski, Michael E; Herb, Mark; Finley, Michael F A; Liu, Yi; Lubin, Mary Lou; Qin, Ning; Reitz, Allen B; Maryanoff, Bruce E
2013-11-27
Broad-spectrum anticonvulsants are of considerable interest as antiepileptic drugs, especially because of their potential for treating refractory patients. Such "neurostabilizers" have also been used to treat other neurological disorders, including migraine, bipolar disorder, and neuropathic pain. We synthesized a series of sulfamide derivatives (4-9, 10a-i, 11a, 11b, 12) and evaluated their anticonvulsant activity. Thus, we identified promising sulfamide 4 (JNJ-26489112) and explored its pharmacological properties. Compound 4 exhibited excellent anticonvulsant activity in rodents against audiogenic, electrically induced, and chemically induced seizures. Mechanistically, 4 inhibited voltage-gated Na(+) channels and N-type Ca(2+) channels and was effective as a K(+) channel opener. The anticonvulsant profile of 4 suggests that it may be useful for treating multiple forms of epilepsy (generalized tonic-clonic, complex partial, absence seizures), including refractory (or pharmacoresistant) epilepsy, at dose levels that confer a good safety margin. On the basis of its pharmacology and other favorable characteristics, 4 was advanced into human clinical studies.
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McComsey, David F.; Smith-Swintosky, Virginia L.; Parker, Michael H.; Brenneman, Douglas E.; Malatynska, Ewa; White, H. Steve; Klein, Brian D.; Wilcox, Karen S.; Milewski, Michael E.; Herb, Mark; Finley, Michael F. A.; Liu, Yi; Lubin, Mary Lou; Qin, Ning; Reitz, Allen B.; Maryanoff, Bruce E.
2014-01-01
Broad-spectrum anticonvulsants are of considerable interest as antiepileptic drugs, especially because of their potential for treating refractory patients. Such “neurostabilizers” have also been used to treat other neurological disorders, including migraine, bipolar disorder, and neuropathic pain. We synthesized a series of sulfamide derivatives (4–9, 10a–i, 11a, 11b, 12) and evaluated their anticonvulsant activity. Thus, we identified promising sulfamide 4 (JNJ-26489112) and explored its pharmacological properties. Compound 4 exhibited excellent anticonvulsant activity in rodents against audiogenic, electrically-induced, and chemically-induced seizures. Mechanistically, 4 inhibited voltage-gated Na+ channels and N-type Ca2+ channels, and was effective as a K+ channel opener. The anticonvulsant profile of 4 suggests that it may be useful for treating multiple forms of epilepsy (generalized tonic-clonic, complex partial, absence seizures), including refractory (or pharmacoresistant) epilepsy, at dose levels that confer a good safety margin. On the basis of its pharmacology and other favorable characteristics, 4 was advanced into human clinical studies. PMID:24205976
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Refractory porcelain enamel passive-thermal-control coating for high-temperature superalloys
NASA Technical Reports Server (NTRS)
Levin, H.; Auker, B. H.; Gardos, M. N.
1973-01-01
Study was conducted to match thermal expansion coefficients thereby preventing enamels from cracking. Report discusses various enamel coatings that are applied to two different high-temperature superalloys. Study may be of interest to manufacturers of chemical equipment, furnaces, and metal components intended for high-temperature applications.
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Li, Kan; Zhang, Hongbo; Tang, Tiantian; Xu, Yunlan; Ying, Diwen; Wang, Yalin; Jia, Jinping
2014-10-01
A TiO2/Ti-Pt photo fuel cell (PFC) was established to generate electricity and degrade organic pollutants simultaneously. The electricity generation was optimized through investigation the influences of photoanode calcination temperature and dissolve oxygen on the resistances existing in PFC. TiO2 light quantum yield was also improved in PFC which resulted in a higher PC degradation efficiency. Two kinds of real textile wastewaters were also employed in this PFC system, 62.4% and 50.0% Coulombic efficiency were obtained for 8 h treatment. These refractory wastewaters with high salinity may become good fuels in PFC because a) TiO2 has no selectivity and can degrade nearly any organic substance, b) no more electrolyte is needed due to the high salinity, c) the energy in wastes can be recovered to generate electricity. The electricity generated by the PFC was further applied on a TiO2/Ti rotating disk photoelectrocatalytic reactor. A bias voltage between 0.6 and 0.75 V could be applied and the PC degradation efficiency was significantly improved. This result was similar with that obtained by a 0.7 V DC power. Copyright © 2014 Elsevier Ltd. All rights reserved.
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NASA Technical Reports Server (NTRS)
Zhu, Dongming; Lee, Kang N.; Miller, Robert A.
2001-01-01
Plasma-sprayed mullite and BSAS coatings have been developed to protect SiC/SiC ceramic matrix composites from high temperature environmental attack. In this study, thermal conductivity and thermal barrier functions of these coating systems are evaluated using a laser high-heat-flux test rig. The effects of water vapor on coating thermal conductivity and durability are studied by using alternating furnace and laser thermal gradient cyclic tests. The influence of laser high thermal-gradient cycling on coating failure modes is also investigated.
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Livesay, Ronald Jason; Mason, Brandon William; Kuhn, Michael Joseph; Rowe, Nathan Carl
2017-04-04
Disclosed are several examples of a system and method for detecting if an article is being tampered with. Included is a covering made of a substrate that is coated with a layer of an electrically conductive material that forms an electrically conductive surface having an electrical resistance. The covering is configured to at least partially encapsulate the article such that the article cannot be tampered with, without modifying the electrical resistance of the electrically conductive surface of the covering. A sensing device is affixed to the electrically conductive surface of the covering and the sensing device monitors the condition of the covering by producing a signal that is indicative of the electrical resistance of the electrically conductive surface of the covering. A measured electrical resistance that differs from a nominal electrical resistance is indicative of a covering that is being tampered with and an alert is communicated to an observer.
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Livesay, Ronald Jason; Mason, Brandon William; Kuhn, Michael Joseph; Rowe, Nathan Carl
2015-10-13
Disclosed are several examples of a system and method for detecting if an article is being tampered with. Included is a covering made of a substrate that is coated with a layer of an electrically conductive material that forms an electrically conductive surface having an electrical resistance. The covering is configured to at least partially encapsulate the article such that the article cannot be tampered with, without modifying the electrical resistance of the electrically conductive surface of the covering. A sensing device is affixed to the electrically conductive surface of the covering and the sensing device monitors the condition of the covering by producing a signal that is indicative of the electrical resistance of the electrically conductive surface of the covering. A measured electrical resistance that differs from a nominal electrical resistance is indicative of a covering that is being tampered with and an alert is communicated to an observer.
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An analysis of electrical conductivity model in saturated porous media
NASA Astrophysics Data System (ADS)
Cai, J.; Wei, W.; Qin, X.; Hu, X.
2017-12-01
Electrical conductivity of saturated porous media has numerous applications in many fields. In recent years, the number of theoretical methods to model electrical conductivity of complex porous media has dramatically increased. Nevertheless, the process of modeling the spatial conductivity distributed function continues to present challenges when these models used in reservoirs, particularly in porous media with strongly heterogeneous pore-space distributions. Many experiments show a more complex distribution of electrical conductivity data than the predictions derived from the experiential model. Studies have observed anomalously-high electrical conductivity of some low-porosity (tight) formations compared to more- porous reservoir rocks, which indicates current flow in porous media is complex and difficult to predict. Moreover, the change of electrical conductivity depends not only on the pore volume fraction but also on several geometric properties of the more extensive pore network, including pore interconnection and tortuosity. In our understanding of electrical conductivity models in porous media, we study the applicability of several well-known methods/theories to electrical characteristics of porous rocks as a function of pore volume, tortuosity and interconnection, to estimate electrical conductivity based on the micro-geometrical properties of rocks. We analyze the state of the art of scientific knowledge and practice for modeling porous structural systems, with the purpose of identifying current limitations and defining a blueprint for future modeling advances. We compare conceptual descriptions of electrical current flow processes in pore space considering several distinct modeling approaches. Approaches to obtaining more reasonable electrical conductivity models are discussed. Experiments suggest more complex relationships between electrical conductivity and porosity than experiential models, particularly in low-porosity formations. However, the available theoretical models combined with simulations do provide insight to how microscale physics affects macroscale electrical conductivity in porous media.
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Murray, Matthew M.; Wilfong, Dennis H.; Lomax, Ralph E.
1998-01-01
An electrical cable for connecting transient voltage surge suppressers to ectrical power panels. A strip of electrically conductive foil defines a longitudinal axis, with a length of an electrical conductor electrically attached to the metallic foil along the longitudinal axis. The strip of electrically conductive foil and the length of an electrical conductor are covered by an insulating material. For impedance matching purposes, triangular sections can be removed from the ends of the electrically conductive foil at the time of installation.
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2018-06-20
Advanced Malignant Solid Neoplasm; Ann Arbor Stage III Childhood Hodgkin Lymphoma; Ann Arbor Stage III Childhood Non-Hodgkin Lymphoma; Ann Arbor Stage IV Childhood Hodgkin Lymphoma; Ann Arbor Stage IV Childhood Non-Hodgkin Lymphoma; Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; EZH2 Gain of Function; EZH2 Gene Mutation; Histiocytosis; Loss of BRG1 Protein Expression; Loss of INI 1 Protein Expression; Low Grade Glioma; Recurrent Childhood Central Nervous System Neoplasm; Recurrent Childhood Ependymoma; Recurrent Childhood Soft Tissue Sarcoma; Recurrent Ewing Sarcoma; Recurrent Glioma; Recurrent Hepatoblastoma; Recurrent Hodgkin Lymphoma; Recurrent Langerhans Cell Histiocytosis; Recurrent Malignant Germ Cell Tumor; Recurrent Malignant Glioma; Recurrent Malignant Solid Neoplasm; Recurrent Medulloblastoma; Recurrent Neuroblastoma; Recurrent Non-Hodgkin Lymphoma; Recurrent Osteosarcoma; Recurrent Peripheral Primitive Neuroectodermal Tumor; Recurrent Rhabdoid Tumor; Recurrent Rhabdomyosarcoma; Recurrent Soft Tissue Sarcoma; Refractory Central Nervous System Neoplasm; Refractory Hodgkin Lymphoma; Refractory Langerhans Cell Histiocytosis; Refractory Malignant Germ Cell Tumor; Refractory Malignant Glioma; Refractory Medulloblastoma; Refractory Neuroblastoma; Refractory Non-Hodgkin Lymphoma; Refractory Osteosarcoma; Refractory Peripheral Primitive Neuroectodermal Tumor; Refractory Rhabdoid Tumor; Refractory Soft Tissue Sarcoma; Rhabdoid Tumor; SMARCA4 Gene Inactivation; SMARCB1 Gene Inactivation; Stage III Soft Tissue Sarcoma AJCC v7; Stage IV Soft Tissue Sarcoma AJCC v7; Wilms Tumor
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Apparatus for Use in Determining Surface Conductivity at Microwave Frequencies
NASA Technical Reports Server (NTRS)
Hearn, Chase P. (Inventor)
1995-01-01
An apparatus is provided for use in determining surface conductivity of a flat or shaped conductive material at microwave frequencies. A plate has an electrically conductive surface with first and second holes passing through the plate. An electrically conductive material under test (MUT) is maintained in a spaced apart relationship with the electrically conductive surface of the plate by one or more nonconductive spacers. A first coupling loop is electrically shielded within the first hole while a second coupling loop is electrically shielded within the second hole. A dielectric resonator element is positioned between the first and second coupling loops, while also being positioned closer to the MUT than the electrically conductive surface of the plate. Microwave energy at an operating frequency f is supplied from a signal source to the first coupling loop while microwave energy received at the second coupling loop is measured. The apparatus is capable of measuring the Q-factor of the dielectric resonator situated in the 'cavity' existing between the electrically conductive surface of the plate and the MUT. Surface conductivity of the electrically conductive surface can be determined via interpolation using: 1 ) the measured Q-factor with the electrically conductive surface in place, and 2) the measured Q-factor when the MUT is replaced with reference standards having known surface conductivities.
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Ibrutinib in Treating Patients With Refractory or Relapsed Lymphoma After Donor Stem Cell Transplant
2017-10-03
Blastoid Variant Mantle Cell Lymphoma; Recurrent Chronic Lymphocytic Leukemia; Recurrent Follicular Lymphoma; Recurrent Hodgkin Lymphoma; Recurrent Mantle Cell Lymphoma; Refractory Chronic Lymphocytic Leukemia; Refractory Follicular Lymphoma; Refractory Hodgkin Lymphoma; Refractory Mantle Cell Lymphoma
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Development of refractories and related products for steel melting, finishing, and casting
NASA Astrophysics Data System (ADS)
Smirnov, A. N.
2013-06-01
The transformation of the consumption of refractories for the production, out-of-furnace treatment, and casting of steel is considered. The main trends in developing the refractory market are shown to be a significant decrease in the specific consumption of refractories per 1 t liquid steel and the predominant application of refractories based on magnesia raw materials and fused corundum for the working layers of melting units, ladles, and tundishes. The main trend in decreasing the specific costs of refractories is the development of refractories based on alternative sources of raw materials, which are cheaper and more available for refractory manufacturers.
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2017-06-30
Recurrent Chronic Lymphocytic Leukemia; Recurrent Extranodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Lymphoplasmacytic Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Nodal Marginal Zone Lymphoma; Recurrent Small Lymphocytic Lymphoma; Recurrent Splenic Marginal Zone Lymphoma; Refractory Chronic Lymphocytic Leukemia; Refractory Extranodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue; Refractory Follicular Lymphoma; Refractory Lymphoplasmacytic Lymphoma; Refractory Nodal Marginal Zone Lymphoma; Refractory Small Lymphocytic Lymphoma; Refractory Splenic Marginal Zone Lymphoma; Richter Syndrome; Waldenstrom Macroglobulinemia
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[Surgery of refractory ischemic arrhythmia].
Viganò, M; Graffigna, A; Salerno, G
1992-03-01
Since June 1980, 138 patients have undergone surgical treatment for refractory ventricular tachycardia due to ischemic heart disease. Electrically guided surgical ablation (EGSA) of the focus was performed in 117 patients, while 14 patients underwent application of automatic implantable cardioverter-defibrillator (AICD), and 8 patients underwent heart transplantation. During the whole period considered, among the EGSA patients an operative mortality of 13 patients was observed (11.4%), with a late mortality of another 14 patients (13.4%). Two early and six late recurrences were described, and 4 cases of sudden or unexplained death, with 2 cases clearly due to an arrhythmic event. Multivariate analysis showed preoperative ejection fraction lower than 25% as a powerful predictor of early mortality (32% vs 0%). Actuarial survival rate of patients with LVEF lower than 25% was 67 +/- 12% vs 95 +/- 2% at one year and 37 +/- 25% vs 94 +/- 8% at 8 years. A high operative mortality was then observed in patients who underwent aneurysmectomy alone or visually guided procedures as compared to electrically guided procedures (75% or 3 deaths out of 4 patients vs 8.5% or 10 out of 113 patients, respectively). Patients who received an AICD with or without associated procedures showed 1 case of in-hospital mortality and no late mortality; in 6 patients at least one shock was delivered; in two patients the AICD was implanted during an EGSA procedure, due to multiple or difficult origins of the arrhythmias. Of patients who underwent heart transplantation one case of later mortality was observed due to malignancy.(ABSTRACT TRUNCATED AT 250 WORDS)
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Cho, Hyun Woo; Kim, Jeongmin; Sung, Bong June, E-mail: jjpark@chonnam.ac.kr, E-mail: bjsung@sogang.ac.kr
We investigate how the electrical conductance of microfibers (made of polymers and conductive nanofillers) decreases upon uniaxial deformation by performing both experiments and simulations. Even though various elastic conductors have been developed due to promising applications for deformable electronic devices, the mechanism at a molecular level for electrical conductance change has remained elusive. Previous studies proposed that the decrease in electrical conductance would result from changes in either distances or contact numbers between conductive fillers. In this work, we prepare microfibers of single walled carbon nanotubes (SWCNTs)/polyvinyl alcohol composites and investigate the electrical conductance and the orientation of SWCNTs uponmore » uniaxial deformation. We also perform extensive Monte Carlo simulations, which reproduce experimental results for the relative decrease in conductance and the SWCNTs orientation. We investigate the electrical networks of SWCNTs in microfibers and find that the decrease in the electrical conductance upon uniaxial deformation should be attributed to a subtle change in the topological structure of the electrical network.« less
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Donnadieu, S; Djian, M C
1998-12-12
NEW OPIOID ANALGESICS: Progress in pain reliet has recently been achieved with the introduction of new opioid analgesics such as tramadol and the pediatric preparation of codeine phosphate as well as powerful long-release opioids which can be administered per os, or percutaneously for transdermal fentanyl. CO-ANALGESICS: Other drugs, mainly antidepressants and anti-convulsants, can be usefully combined with analgesics. New serotonin uptake inhibitors and anticonvulsants (gabapentin and lamotrigin) have the advantage of better tolerance. None of these drugs has marketing approval in France for their pain relieving effects. The same is true for clonidine and neostigmine which, after spinal infusion, potentialize opioids and for ketamine which can relieve neuropathy pain by dissociative anesthesia. NEW ANTI-MIGRAINE DRUGS: New drugs have been developed for specific types of pain such as migraine. The new "triptans" are tolerated better than sumatriptan and is reimbursed by the national social security. REFRACTORY NEUROPATHY PAIN: Indications for electrical stimulation techniques conducted in a neurosurgery unit have been identified. Stimulators may be implanted in spinal or supra-spinal localizations. REGULATORY ASPECTS: New legislation has reorganized health care for pain relief in France. The new texts take into consideration personnel training, the health care network and progress in therapeutics.
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Jørgensen, Cecilie Siggaard; Kamperis, Konstantinos; Borch, Luise; Borg, Britt; Rittig, Søren
2017-09-01
In a third of all children with monosymptomatic nocturnal enuresis their condition is refractory to first line treatments. Transcutaneous electrical nerve stimulation has been documented to be efficacious in children with daytime incontinence. We investigated the effect of transcutaneous electrical nerve stimulation in children with monosymptomatic nocturnal enuresis without nocturnal polyuria. Children with monosymptomatic nocturnal enuresis (3 or more wet nights per week) and no nocturnal polyuria were randomized to treatment with active or sham transcutaneous electrical nerve stimulation involving 1-hour sessions twice daily for 10 weeks in a double-blind design. Of the 52 children with monosymptomatic nocturnal enuresis included in the study 47 completed treatment (mean age 9.5 ± 2.1 years, 38 males). None of the children experienced a full response with complete remission of enuresis. Treatment with transcutaneous electrical nerve stimulation did not lead to significant changes in number of wet nights, nocturnal urine production on wet or dry nights, maximum voided volume with and without first morning voided volume, or voiding frequency when comparing parameters before and after treatment. The present study demonstrates no anti-enuretic effect of transcutaneous electrical nerve stimulation in children with monosymptomatic nocturnal enuresis without nocturnal polyuria. Nocturnal urine production and bladder capacity remained unchanged during and after treatment with transcutaneous electrical nerve stimulation. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
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Campbell, Jeremy B [Torrance, CA; Newson, Steve [Redondo Beach, CA
2011-11-15
A power module assembly of the type suitable for deployment in a vehicular power inverter, wherein the power inverter has a grounded chassis, is provided. The power module assembly comprises a conductive base layer electrically coupled to the chassis, an insulating layer disposed on the conductive base layer, a first conductive node disposed on the insulating layer, a second conductive node disposed on the insulating layer, wherein the first and second conductive nodes are electrically isolated from each other. The power module assembly also comprises a first capacitor having a first electrode electrically connected to the conductive base layer, and a second electrode electrically connected to the first conductive node, and further comprises a second capacitor having a first electrode electrically connected to the conductive base layer, and a second electrode electrically connected to the second conductive node.
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Plasma Exchange for Refractory MDA5 Myositis and ILD
2017-04-26
investigations. S02 ISG/JAC ( Ethics Review) and Public Affa irs (S9 MOW/PA) for review and then forward you a final letter of approval or disapproval. 9...Medical and Technical Papers, for additional information. 11 . The Joint Ethics Regulation (JER) DoD SS00.07 -R, Standards of Conduct. provides...standards of ethical conduct for all DoD personnel and their interactions with other non-DoD entities. organizations, societies. conferences, etc. Part of
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Thermo-Mechanical and Thermal behavior of High-Temperature Structural Materials.
1982-12-31
34-’- Mr. 3. D. SilboldMr-J-..ibl Columbus, OH 43201 Coor Porcelain Company 17750 W. 32nd Avenue Dr. R. E. Engdahl Golden, CO 80401 Deposits and Composites ...number) Thermal shock, thermal stress, thermal diffusivity, thermal conductivity; refractories, composites , radiation heat transfer, cyclic heating...Hasselman and R. Ruh, "Effect of Hot-Pressing 4 -; Temperature on the Thermal Diffusivity/Conductivity of SiC-AIN Composites ." III M. A. Bucknam, L. D
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2018-02-12
Prolymphocytic Leukemia; Recurrent Adult Hodgkin Lymphoma; Recurrent Childhood Hodgkin Lymphoma; Recurrent Childhood Non-Hodgkin Lymphoma; Recurrent Chronic Lymphocytic Leukemia; Recurrent Non-Hodgkin Lymphoma; Recurrent Small Lymphocytic Lymphoma; Refractory Childhood Hodgkin Lymphoma; Refractory Chronic Lymphocytic Leukemia; Refractory Hodgkin Lymphoma; Refractory Non-Hodgkin Lymphoma; Refractory Small Lymphocytic Lymphoma; T-Cell Chronic Lymphocytic Leukemia; T-Cell Prolymphocytic Leukemia
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2018-01-25
Grade 3a Follicular Lymphoma; Recurrent Burkitt Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Follicular Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Lymphoplasmacytic Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Waldenstrom Macroglobulinemia; Refractory Burkitt Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Follicular Lymphoma; Refractory Lymphoplasmacytic Lymphoma; Refractory Mantle Cell Lymphoma
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Ashrafi, Mahmoud Reza; Hosseini, Seyed Ahmad; Zamani, Gholam Reza; Mohammadi, Mahmoud; Tavassoli, Alireza; Badv, Reza Shervin; Heidari, Morteza; Karimi, Parviz; Malamiri, Reza Azizi
2017-03-01
To evaluate the efficacy, safety, and tolerability of a classic 4:1 ketogenic diet using a formula-based powder in infants and children with refractory seizures who are reluctant to eat homemade foods. We conducted an open label trial and administered a ketogenic diet using formula-based power (Ketocal ® ). Twenty-seven infants and children aged between 12 months and 5 years were enrolled who had refractory seizures and were reluctant to eat homemade foods. Of 27 children, 5 were lost to follow-up and 22 were remained at the end of the study. After 4 months, the median frequency of seizures per week was reduced >50% in 68.2% of patients, while 9/22 children (40.9%) showed a 50-90% reduction in seizure frequency per week, and 6/22 children (27.3%) showed more than 90% reduction in seizure frequency per week. Over the study course, 6/22 (27%) children who continued to receive the diet developed constipation, one child developed gastroesophageal reflux, and one child developed hypercholesterolemia. None of these children discontinued the diet because of the complications. Thirteen children and their parents (59%) reported that the diet was palatable and tolerable enough. The ketogenic diet using a formula-based powder (Ketocal ® ) is effective, safe, and tolerable in infants and children with refractory seizures who are reluctant to eat homemade foods according to the rules of the ketogenic diet.
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Sanabria-Castro, A; Henríquez-Varela, F; Monge-Bonilla, C; Lara-Maier, S; Sittenfeld-Appel, M
2017-03-16
Given that epileptic seizures and non-epileptic paroxysmal events have similar clinical manifestations, using specific diagnostic methods is crucial, especially in patients with drug-resistant epilepsy. Prolonged video electroencephalography monitoring during epileptic seizures reveals epileptiform discharges and has become an essential procedure for epilepsy diagnosis. The main purpose of this study is to characterise paroxysmal events and compare patterns in patients with refractory epilepsy. We conducted a retrospective analysis of medical records from 91 patients diagnosed with refractory epilepsy who underwent prolonged video electroencephalography monitoring during hospitalisation. During prolonged video electroencephalography monitoring, 76.9% of the patients (n=70) had paroxysmal events. The mean number of events was 3.4±2.7; the duration of these events was highly variable. Most patients (80%) experienced seizures during wakefulness. The most common events were focal seizures with altered levels of consciousness, progressive bilateral generalized seizures and psychogenic non-epileptic seizures. Regarding all paroxysmal events, no differences were observed in the number or type of events by sex, in duration by sex or age at onset, or in the number of events by type of event. Psychogenic nonepileptic seizures were predominantly registered during wakefulness, lasted longer, started at older ages, and were more frequent in women. Paroxysmal events recorded during prolonged video electroencephalography monitoring in patients with refractory epilepsy show similar patterns and characteristics to those reported in other latitudes. Copyright © 2017 The Author(s). Publicado por Elsevier España, S.L.U. All rights reserved.
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Sultan, Sadia; Irfan, Syed Mohammed; Jawed, Syeda Narisa
2016-01-01
Myelodysplastic syndrome (MDS) is a clonal disorder of hemopoeitic stem cells, characterized by infective hematopoiesis, peripheral cytopenias along with hypercellularity of marrow and marked dysplastic features. Our aim was to study the spectrum of the WHO classification in adult Pakistani patients with MDS at disease presentation. This retrospective descriptive study was conducted at Liaquat National Hospital and Medical College, extending from January 2010 to December 2014. Patient data were retrieved from the maintained archives. Overall, 45 patients were diagnosed at our institution with de novo MDS during the study period. There were 28 males and 17 females. Age ranged between 18 and 95 years with a mean of 57.6±17.4 years. The male to female ratio was 1.7:1. According to the WHO classification, 53.3% had refractory cytopenia with multilineage dysplasia, 22.2% had refractory cytopenia with unilineage dysplasia, 4.4% each had refractory anemia with excess of blasts-1 and II and 15.5% had MDS unclassified. The main presenting complaints were generalized fatigue (60%), fever (33.3%), dyspnea (15.5%), bleeding (13.3%) and weight loss (11.1%). Physical examination revealed pallor in 37.7%, followed by petechial and purpuric rashes in 20% of patients. Hemoglobin was <10 g/dl in 41 (91.1%). Pancytopenia and bicytopenia were noted in 18 (40%) and 14 (31.1%) respectively. MDS in our patients presents at a relatively young age. Refractory c ytopenia with multilineage dysplasia was the dominant disease variant in our setting.
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2018-03-02
Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Follicular Lymphoma; Recurrent Lymphoplasmacytic Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Follicular Lymphoma; Refractory Lymphoplasmacytic Lymphoma; Refractory Mantle Cell Lymphoma
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2014-06-10
Childhood Myelodysplastic Syndromes; de Novo Myelodysplastic Syndromes; Previously Treated Myelodysplastic Syndromes; Refractory Anemia; Refractory Anemia With Excess Blasts; Refractory Anemia With Ringed Sideroblasts; Refractory Cytopenia With Multilineage Dysplasia; Secondary Myelodysplastic Syndromes; Unspecified Childhood Solid Tumor, Protocol Specific
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2018-04-11
CD20 Positive; Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Chronic Lymphocytic Leukemia; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Follicular Lymphoma; Recurrent Lymphoplasmacytic Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Follicular Lymphoma; Refractory Lymphoplasmacytic Lymphoma; Refractory Mantle Cell Lymphoma; Refractory Transformed Indolent Non-Hodgkin Lymphoma
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Electrically-conductive proppant and methods for making and using same
Cannan, Chad; Roper, Todd; Savoy, Steve; Mitchell, Daniel R.
2016-09-06
Electrically-conductive sintered, substantially round and spherical particles and methods for producing such electrically-conductive sintered, substantially round and spherical particles from an alumina-containing raw material. Methods for using such electrically-conductive sintered, substantially round and spherical particles in hydraulic fracturing operations.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Tseng, Yolanda D., E-mail: ydt2@uw.edu; Chen, Yu-Hui; Catalano, Paul J.
Purpose: To evaluate the response rate (RR) and time to local recurrence (TTLR) among patients who received salvage radiation therapy for relapsed or refractory aggressive non-Hodgkin lymphoma (NHL) and investigate whether RR and TTLR differed according to disease characteristics. Methods and Materials: A retrospective review was performed for all patients who completed a course of salvage radiation therapy between January 2001 and May 2011 at Brigham and Women's Hospital/Dana-Farber Cancer Institute. Separate analyses were conducted for patients treated with palliative and curative intent. Predictors of RR for each subgroup were assessed using a generalized estimating equation model. For patients treatedmore » with curative intent, local control (LC) and progression-free survival were estimated with the Kaplan-Meier method; predictors for TTLR were evaluated using a Cox proportional hazards regression model. Results: Salvage radiation therapy was used to treat 110 patients to 121 sites (76 curative, 45 palliative). Salvage radiation therapy was given as part of consolidation in 18% of patients treated with curative intent. Median dose was 37.8 Gy, with 58% and 36% of curative and palliative patients, respectively, receiving 39.6 Gy or higher. The RR was high (86% curative, 84% palliative). With a median follow-up of 4.8 years among living patients, 5-year LC and progression-free survival for curative patients were 66% and 34%, respectively. Refractory disease (hazard ratio 3.3; P=.024) and lack of response to initial chemotherapy (hazard ratio 4.3; P=.007) but not dose (P=.93) were associated with shorter TTLR. Despite doses of 39.6 Gy or higher, 2-year LC was only 61% for definitive patients with refractory disease or disease that did not respond to initial chemotherapy. Conclusions: Relapsed or refractory aggressive NHL is responsive to salvage radiation therapy, and durable LC can be achieved in some cases. However, refractory disease is associated with a shorter TTLR, suggesting that radiation dose escalation, addition of radiosensitizers, or a combination of both may be indicated in these patients.« less
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Qazi, Y; Kheirkhah, A; Blackie, C; Cruzat, A; Trinidad, M; Williams, C; Korb, D R; Hamrah, P
2015-01-01
Purpose The utility of in vivo confocal microscopy (IVCM) in the investigation of palpebral conjunctival and corneal inflammation in patients with meibomian gland dysfunction (MGD)-associated refractory dry eye symptoms following gland expression, despite objective clinical improvement. Methods A retrospective, observational pilot study was conducted evaluating five patients with MGD-associated refractory dry eye symptoms and three control groups: symptomatic untreated MGD patients (n=3), treatment-responsive MGD patients with improved symptoms (n=3) and asymptomatic healthy normals (n=11). Ocular surface disease index (OSDI) scores, tear break-up time (TBUT), the number of meibomian glands yielding liquid secretion (MGYLS), palpebral conjunctival epithelial and substantia propria immune cell (EIC, SIC), and corneal dendritic cell (DC) densities were measured. Results Despite clinical improvement (TBUT: 6.4±1.2 s to 10.1±2.1 s, P=0.03; MGYLS: 3.5±0.8 glands to 7.0±1.1 glands, P=0.13) and a normal clinical examination post treatment, MGD patients remained symptomatic. IVCM revealed increased immune cells in the palpebral conjunctiva (refractory MGD EIC=592.6±110.1 cells/mm2; untreated MGD EIC=522.6±104.7 cells/mm2, P=0.69; responsive MGD EIC=194.9±119.4 cells/mm2, P<0.01; normals EIC=123.7±19.2 cells/mm2, P< 0.001), but not the cornea (refractory MGD DC=60.9±28.3 cells/mm2; normals DC=25.9±6.3 cells/mm2; P=0.43). EIC did not correlate with TBUT (Rs=−0.26, P=0.33). OSDI scores correlated with both EIC (Rs=0.76, P<0.001) and TBUT (Rs=−0.69, P<0.01) but not SIC. Intraglandular immune cells were also seen. Conclusion MGD-associated refractory symptoms and the symptom-sign disparity may be explained by clinically non-apparent, active inflammation of the palpebral conjunctiva as detected by IVCM. These patients may benefit from anti-inflammatory therapy. PMID:26088680
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Direct recordings from the auditory cortex in a cochlear implant user.
Nourski, Kirill V; Etler, Christine P; Brugge, John F; Oya, Hiroyuki; Kawasaki, Hiroto; Reale, Richard A; Abbas, Paul J; Brown, Carolyn J; Howard, Matthew A
2013-06-01
Electrical stimulation of the auditory nerve with a cochlear implant (CI) is the method of choice for treatment of severe-to-profound hearing loss. Understanding how the human auditory cortex responds to CI stimulation is important for advances in stimulation paradigms and rehabilitation strategies. In this study, auditory cortical responses to CI stimulation were recorded intracranially in a neurosurgical patient to examine directly the functional organization of the auditory cortex and compare the findings with those obtained in normal-hearing subjects. The subject was a bilateral CI user with a 20-year history of deafness and refractory epilepsy. As part of the epilepsy treatment, a subdural grid electrode was implanted over the left temporal lobe. Pure tones, click trains, sinusoidal amplitude-modulated noise, and speech were presented via the auxiliary input of the right CI speech processor. Additional experiments were conducted with bilateral CI stimulation. Auditory event-related changes in cortical activity, characterized by the averaged evoked potential and event-related band power, were localized to posterolateral superior temporal gyrus. Responses were stable across recording sessions and were abolished under general anesthesia. Response latency decreased and magnitude increased with increasing stimulus level. More apical intracochlear stimulation yielded the largest responses. Cortical evoked potentials were phase-locked to the temporal modulations of periodic stimuli and speech utterances. Bilateral electrical stimulation resulted in minimal artifact contamination. This study demonstrates the feasibility of intracranial electrophysiological recordings of responses to CI stimulation in a human subject, shows that cortical response properties may be similar to those obtained in normal-hearing individuals, and provides a basis for future comparisons with extracranial recordings.
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New mechanism of spiral wave initiation in a reaction-diffusion-mechanics system.
Weise, Louis D; Panfilov, Alexander V
2011-01-01
Spiral wave initiation in the heart muscle is a mechanism for the onset of dangerous cardiac arrhythmias. A standard protocol for spiral wave initiation is the application of a stimulus in the refractory tail of a propagating excitation wave, a region that we call the "classical vulnerable zone." Previous studies of vulnerability to spiral wave initiation did not take the influence of deformation into account, which has been shown to have a substantial effect on the excitation process of cardiomyocytes via the mechano-electrical feedback phenomenon. In this work we study the effect of deformation on the vulnerability of excitable media in a discrete reaction-diffusion-mechanics (dRDM) model. The dRDM model combines FitzHugh-Nagumo type equations for cardiac excitation with a discrete mechanical description of a finite-elastic isotropic material (Seth material) to model cardiac excitation-contraction coupling and stretch activated depolarizing current. We show that deformation alters the "classical," and forms a new vulnerable zone at longer coupling intervals. This mechanically caused vulnerable zone results in a new mechanism of spiral wave initiation, where unidirectional conduction block and rotation directions of the consequently initiated spiral waves are opposite compared to the mechanism of spiral wave initiation due to the "classical vulnerable zone." We show that this new mechanism of spiral wave initiation can naturally occur in situations that involve wave fronts with curvature, and discuss its relation to supernormal excitability of cardiac tissue. The concept of mechanically induced vulnerability may lead to a better understanding about the onset of dangerous heart arrhythmias via mechano-electrical feedback.
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Synthesis and Characterization of Low-Cost Superhard Transition-Metal Borides
NASA Astrophysics Data System (ADS)
Kaner, Richard
2013-06-01
The increasing demand for high-performance cutting and forming tools, along with the shortcomings of traditional tool materials such as diamond (unable to cut ferrous materials), cubic boron nitride (expensive) and tungsten carbide (relatively-low hardness), has motivated the search for new superhard materials for these applications. This has led us to a new class of superhard materials, dense refractory transition-metal borides, which promise to address some of the existing problems of conventional superhard materials. For example, we have synthesized rhenium diboride (ReB2) using arc melting at ambient pressure. This superhard material has demonstrated an excellent electrical conductivity and superior mechanical properties, including a Vickers hardness of 48.0 GPa (under an applied load of 0.49 N). To further increase the hardness and lower the materials costs, we have begun exploring high boron content metal borides including tungsten tetraboride (WB4) . We have synthesized WB4 by arc melting and studied its hardness and high-pressure behavior. With a similar Vickers hardness (43.3 GPa under a load of 0.49 N) and bulk modulus (326-339 GPa) to ReB2, WB4 offers a lower cost alternative and has the potential to be used in cutting tools. To further enhance the hardness of this superhard metal, we have created the binary and ternary solid solutions of WB4 with Cr, Mn and Ta, the results of which show a hardness increase of up to 20 percent. As with other metals, these metallic borides can be readily cut and shaped using electric discharge machining (EDM).
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NASA Astrophysics Data System (ADS)
Hui, KeShi; Dai, LiDong; Li, HePing; Hu, HaiYing; Jiang, JianJun; Sun, WenQing; Zhang, Hui
2017-03-01
The electrical conductivity of pyroxene andesite was in situ measured under conditions of 1.0-2.0 GPa and 673-1073 K using a YJ-3000t multi-anvil press and Solartron-1260 Impedance/Gain-phase analyzer. Experimental results indicate that the electrical conductivities of pyroxene andesite increase with increasing temperature, and the electrical conductivities decrease with the rise of pressure, and the relationship between electrical conductivity ( σ) and temperature ( T) conforms to an Arrhenius relation within a given pressure and temperature range. When temperature rises up to 873-923 K, the electrical conductivities of pyroxene andesite abruptly increase, and the activation enthalpy increases at this range, which demonstrates that pyroxene andesite starts to dehydrate. By the virtue of the activation enthalpy (0.35-0.42 eV) and the activation volume (-6.75 ± 1.67 cm3/mole) which characterizes the electrical properties of sample after dehydration, we consider that the conduction mechanism is the small polaron conduction before and after dehydration, and that the rise of carrier concentration is the most important reason of increased electrical conductivity.
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Electrically conductive cellulose composite
Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan
2010-05-04
An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.
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Axicabtagene Ciloleucel Expanded Access Study
2018-05-29
Relapsed/Refractory Diffuse Large B Cell Lymphoma; Relapsed/Refractory Primary Mediastinal B Cell Lymphoma; Relapsed/Refractory Transformed Follicular Lymphoma; Relapsed/Refractory High-Grade B-Cell Lymphoma
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Elvan, A; Wylie, K; Zipes, D P
1996-12-01
We assessed the effects of pacing-induced chronic atrial fibrillation (AF) on sinus node function, intra-atrial conduction, and atrial refractoriness. In 15 mongrel dogs (20 to 30 kg), AV nodal block was produced by radiofrequency catheter ablation, and a ventricular-inhibited (VVI) pacemaker (Minix 8330, Medtronic) was implanted and programmed to pace at 80 pulses per minute. In 11 of these dogs, right atrial endocardial pacing leads were connected to a pulse generator (Itrel 7432, Medtronic) and set at a rate of 20 Hz to induce AF. Corrected sinus node recovery time, P-wave duration, 24-hour Holter ECG to assess AF duration, maximal heart rate in response to isoproterenol (10 micrograms/min), intrinsic heart rate after administration of atropine (0.04 mg/kg) and propranolol (0.1 mg/kg), and atrial effective refractory periods (ERPs) were obtained at baseline (EPS-1) and after 2 to 6 weeks (EPS-2) of VVI pacing alone (n = 4) or VVI pacing and rapid atrial pacing (n = 11). At EPS-2, corrected sinus node recovery time and P-wave duration were prolonged, maximal heart rate and intrinsic heart rate were decreased, atrial ERPs were shortened, and the duration of AF was increased significantly compared with EPS-1. These changes partially reversed toward baseline 1 week after conversion to sinus rhythm. Sinus node function and AF inducibility observed in the control dogs that underwent ventricular pacing alone (n = 4) did not change. Pacing-induced chronic AF induces sinus node dysfunction, prolongs intra-atrial conduction time, shortens atrial refractoriness, and perpetuates AF, changes that reverse gradually after termination of AF.
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Reduction of atrial fibrillation by Tanshinone IIA in chronic heart failure.
He, Zhifeng; Sun, Changzheng; Xu, Yi; Cheng, Dezhi
2016-12-01
The aim of the present study was to confirm the effect of Tanshinone IIA (TAN) on the prevention of AF in chronic heart failure (CHF), and to elucidate the underlying electrophysiological mechanisms for the antiarrhythmic effects of TAN at the level of the atrium in an experimental model of CHF. In 10 female rabbits, CHF was induced by rapid ventricular pacing, leading to a significant decrease in ejection fraction in the presence of a dilated left ventricle and atrial enlargement. Twelve rabbits were sham-operated and served as controls. Isolated hearts were perfused using the Langendorff method. Burst pacing was used to induce AF. Monophasic action potential recordings showed an increase of atrial action potential duration (aAPD) and effective refractory period (aERP) in CHF hearts compared with sham hearts. Infusion of acetylcholine (1μm) and isoproterenol (1μm) led to AF in all failing hearts and in 11 sham hearts. Simultaneous infusion of TAN (10μm) remarkably reduced inducibility of AF in 50% of sham and 50% of failing hearts. TAN had no effect on aAPD but significantly increased aERP, leading to a marked increase in atrial post-repolarization refractoriness. Moreover, TAN application moderately increased interatrial conduction time. TAN has been shown to be effective in reducing the inducibility of AF in an experimental model of AF. The antiarrhythmic effect is mainly due to prolongations of atrial post-repolarization refractoriness and a moderate increase in interatrial conduction time. Copyright © 2016. Published by Elsevier Masson SAS.
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Insulating effectiveness of self-spacing dimpled foil
NASA Technical Reports Server (NTRS)
Bond, J. A.
1972-01-01
Experimental data are graphed for determining conductive heat losses of multilayer insulation as function of number of foil layers. Foil was 0.0051 cm thick Nb, 1% Zr refractory alloy, dimpled to 0.0254 cm with approximately 28 dimples/sq cm. Heat losses were determined at 0.1 microtorr between 700 and 1089 K.
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Experimental analysis of electrical properties of composite materials
NASA Astrophysics Data System (ADS)
Fiala, L.; Rovnaník, P.; Černý, R.
2017-02-01
Dry cement-based composites are electrically non-conductive materials that behave in electric field like dielectrics. However, a relatively low amount of electrically conductive admixture significantly increases the electrical conductivity which extends applicability of such materials in practice. Therefore, they can be used as self-monitoring sensors controlling development of cracks; as sensors monitoring moisture content or when treated by an external electrical voltage as heat sources used for deicing of material's surface layer. Alkali-activated aluminosilicates (AAA), as competing materials to cement-based materials, are intensively investigated in the present due to their superior durability and environmental impact. Whereas the electrical properties of AAA are similar to those cement-based, they can be enhanced in the same way. In both cases, it is crucial to find a reasonable amount of electrically conductive phase to design composites with a sufficient electrical conductivity at an affordable price. In this paper, electrical properties of composites based on AAA binder and electrically conductive admixture represented by carbon nanotubes (CNT) are investigated. Measurements of electrical properties are carried out by means of 2-probes DC technique on nine types of samples; reference sample without the conductive phase and samples with CNT admixture in amount of 0.1 % - 2.5 % by vol. A significant increase of the electrical conductivity starts from the amount of 0.5 % CNT admixture and in case of 2.5 % CNT is about three orders of magnitude higher compared to the reference sample.
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NASA Astrophysics Data System (ADS)
Steiner, Adam M.; Campbell, Paul C.; Yager-Elorriaga, David A.; Cochrane, Kyle R.; Mattsson, Thomas R.; Jordan, Nicholas M.; McBride, Ryan D.; Lau, Y. Y.; Gilgenbach, Ronald M.
2018-03-01
Presented are the results from the liner ablation experiments conducted at 550 kA on the Michigan Accelerator for Inductive Z-Pinch Experiments. These experiments were performed to evaluate a hypothesis that the electrothermal instability (ETI) is responsible for the seeding of magnetohydrodynamic instabilities and that the cumulative growth of ETI is primarily dependent on the material-specific ratio of critical temperature to melting temperature. This ratio is lower in refractory metals (e.g., tantalum) than in non-refractory metals (e.g., aluminum or titanium). The experimental observations presented herein reveal that the plasma-vacuum interface is remarkably stable in tantalum liner ablations. This stability is particularly evident when contrasted with the observations from aluminum and titanium experiments. These results are important to various programs in pulsed-power-driven plasma physics that depend on liner implosion stability. Examples include the magnetized liner inertial fusion (MagLIF) program and the cylindrical dynamic material properties program at Sandia National Laboratories, where liner experiments are conducted on the 27-MA Z facility.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Tomar, Vikas
2017-03-06
DoE-NETL partnered with Purdue University to predict the creep and associated microstructure evolution of tungsten-based refractory alloys. Researchers use grain boundary (GB) diagrams, a new concept, to establish time-dependent creep resistance and associated microstructure evolution of grain boundaries/intergranular films GB/IGF controlled creep as a function of load, environment, and temperature. The goal was to conduct a systematic study that includes the development of a theoretical framework, multiscale modeling, and experimental validation using W-based body-centered-cubic alloys, doped/alloyed with one or two of the following elements: nickel, palladium, cobalt, iron, and copper—typical refractory alloys. Prior work has already established and validated amore » basic theory for W-based binary and ternary alloys; the study conducted under this project extended this proven work. Based on interface diagrams phase field models were developed to predict long term microstructural evolution. In order to validate the models nanoindentation creep data was used to elucidate the role played by the interface properties in predicting long term creep strength and microstructure evolution.« less
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2018-03-28
Breast Adenocarcinoma; Recurrent Breast Carcinoma; Recurrent Hodgkin Lymphoma; Recurrent Mycosis Fungoides; Recurrent Non-Hodgkin Lymphoma; Recurrent Primary Cutaneous T-Cell Non-Hodgkin Lymphoma; Refractory Hodgkin Lymphoma; Refractory Mycosis Fungoides; Refractory Nodal Marginal Zone Lymphoma; Refractory Non-Hodgkin Lymphoma; Refractory Primary Cutaneous T-Cell Non-Hodgkin Lymphoma; Stage IV Breast Cancer AJCC v6 and v7
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Laboratory Investigation of Mineralization of Refractory Nitrogen from Sewage Treatment Plants
NASA Astrophysics Data System (ADS)
Benoit, Gaboury; Wang, Peng
2017-12-01
Laboratory studies were conducted and modeled to evaluate whether refractory organic nitrogen in tertiary-treated wastewater effluent could become bioavailable by conversion to mineral forms. Multiday incubations of effluent collected from the Branford and New Haven, Connecticut, waste water treatment plants (WWTP) revealed low but steady conversion of organic nitrogen to nitrate (NO3 -). In Branford, the principal form of organic nitrogen was dissolved, and in New Haven it was particulate. Modeling suggested that in both the cases conversion to NO3 - from organic forms occurred at several per cent per day, and appeared to happen via the intermediary NH4 +. The results suggest that organic nitrogen may be an important source of bioavailable N, contributing to the problem of hypoxia in Long Island Sound and other estuaries.
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Origin of cometary and chondritic refractory organics: Ion irradiation experiments
NASA Astrophysics Data System (ADS)
Quirico, E.; Faure, M.; Faure, A.; Baklouti, D.; Boduch, P.; Rothard, H.; Ballanzat, E.; Dartois, E.; Brunetto, R.; Bonal, L.; Beck, P.; Schmitt, B.; Duprat, J.; Engrand, C.
2017-09-01
The formation process of Refractory Organic matter present in chondrites and Interplanetary Dust Particles (IDPs) of cometary and asteroidal origin is a debated issue. Earlier studies have advocated a formation step in a hot environment, however the potential role of ion irradiation has been so far poorly constrained. We present here experimental simulations that address this issue, comprising thermal degradation and ion irradiation experiments conducted at GANIL (Caen France) and CSNSM (Orsay France). We show that unlike thermal reactions, ion irradiation might lead to ROM-like material under very stringent conditions on both the nuclear dose and the nature of precursor. These very narrow conditions suggest that forming ROM without any action of thermal reactions is extremely difficult in astrophysical environments, either ISM or the proto-solar disk.
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Laboratory Investigation of Mineralization of Refractory Nitrogen from Sewage Treatment Plants.
Benoit, Gaboury; Wang, Peng
2017-12-01
Laboratory studies were conducted and modeled to evaluate whether refractory organic nitrogen in tertiary-treated wastewater effluent could become bioavailable by conversion to mineral forms. Multiday incubations of effluent collected from the Branford and New Haven, Connecticut, waste water treatment plants (WWTP) revealed low but steady conversion of organic nitrogen to nitrate (NO 3 - ). In Branford, the principal form of organic nitrogen was dissolved, and in New Haven it was particulate. Modeling suggested that in both the cases conversion to NO 3 - from organic forms occurred at several per cent per day, and appeared to happen via the intermediary NH 4 + . The results suggest that organic nitrogen may be an important source of bioavailable N, contributing to the problem of hypoxia in Long Island Sound and other estuaries.
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Removal of pharmaceuticals from secondary effluents by an electro-peroxone process.
Yao, Weikun; Wang, Xiaofeng; Yang, Hongwei; Yu, Gang; Deng, Shubo; Huang, Jun; Wang, Bin; Wang, Yujue
2016-01-01
This study compared the removal of pharmaceuticals from secondary effluents of wastewater treatment plants (WWTPs) by conventional ozonation and the electro-peroxone (E-peroxone) process, which involves electrochemically generating H2O2 in-situ from O2 in sparged O2 and O3 gas mixture (i.e., ozone generator effluent) during ozonation. Several pharmaceuticals with kO3 ranging from <0.1 to 6.8 × 10(5) M(-1) s(-1) were spiked into four secondary effluents collected from different WWTPs, and then treated by ozonation and the E-peroxone process. Results show that both processes can rapidly remove ozone reactive pharmaceuticals (diclofenac and gemfibrozil), while the E-peroxone process can considerably accelerate the removal of ozone-refractory pharmaceuticals (e.g., ibuprofen and clofibric acid) via indirect oxidation with OH generated from the reaction of sparged O3 with electro-generated H2O2. Compared with ozonation, the E-peroxone process enhanced the removal kinetics of ozone-refractory pharmaceuticals in the four secondary effluents by ∼40-170%, and the enhancement was more pronounced in secondary effluents that had relatively lower effluent organic matter (EfOM). Due to its higher efficiency for removing ozone-refractory pharmaceuticals, the E-peroxone process reduced the reaction time and electrical energy consumption required to remove ≥90% of all spiked pharmaceuticals from the secondary effluents as compared to ozonation. These results indicate that the E-peroxone process may provide a simple and effective way to improve existing ozonation system for pharmaceutical removal from secondary effluents. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Shah, Nilesh; Pande, Nikhil; Bhat, Tushar; Murke, Mukund; Andrade, Chittaranjan
2012-06-01
Electroconvulsive therapy (ECT) raises the seizure threshold. This physiological change may benefit patients with seizure disorders. Whereas ECT has recently been used to terminate medication-refractory status epilepticus, there is little current literature on its planned administration as a specific maintenance treatment for medication-refractory epilepsy. We used maintenance ECT to treat an 18-year-old man with a long-standing generalized tonic-clonic seizure disorder who had shown poor response to several antiepileptic drugs administered in combination with antiepileptic medication compliance confirmed through drug level monitoring. A total of 52 ECTs were administered across nearly 20 months at a mean frequency of once in nearly 12 days. From the very outset, ECT dramatically decreased the frequency of spontaneous seizures from approximately 6 to 24 per week at baseline to approximately 1 to 2 per week after ECT initiation. The efficacy of maintenance ECT in spontaneous seizure prophylaxis was greater when the ECT treatment interval was narrower. Improvement with ECT was associated with improved behavior and improved psychosocial functioning on clinical report. No cognitive or other adverse effects were reported or clinically ascertained. The ECT charge administered at the last 10 treatment sessions was 1434 millicoulombs. This is probably the highest electrical stimulus dose recorded in literature. Maintenance ECT may reduce the frequency of breakthrough seizures in patients with seizure disorder that is inadequately responsive to antiepileptic medication regimes. Very high ECT seizure thresholds may be observed when many antiepileptic drugs are concurrently administered in high doses.
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Method of forming an electrically conductive cellulose composite
Evans, Barbara R [Oak Ridge, TN; O'Neill, Hugh M [Knoxville, TN; Woodward, Jonathan [Ashtead, GB
2011-11-22
An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.
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NASA Astrophysics Data System (ADS)
Dalla, P. T.; Alafogianni, P.; Tragazikis, I. K.; Exarchos, D. A.; Dassios, K.; Barkoula, N.-M.; Matikas, T. E.
2015-03-01
Cement-based materials have in general low electrical conductivity. Electrical conductivity is the measure of the ability of the material to resist the passage of electrical current. The addition of a conductive admixture such as Multi-Walled Carbon Nanotubes (MWCNTs) in a cement-based material increases the conductivity of the structure. This research aims to characterize nano-modified cement mortars with MWCNT reinforcements. Such nano-composites would possess smartness and multi-functionality. Multifunctional properties include electrical, thermal and piezo-electric characteristics. One of these properties, the electrical conductivity, was measured using a custom made apparatus that allows application of known D.C. voltage on the nano-composite. In this study, the influence of different surfactants/plasticizers on CNT nano-modified cement mortar specimens with various concentrations of CNTs (0.2% wt. cement CNTs - 0.8% wt. cement CNTs) on the electrical conductivity is assessed.
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NASA Astrophysics Data System (ADS)
Hassan, Huzairy; Jin, Bo; Dai, Sheng; Ngau, Cornelius
2016-11-01
The formation of microbial biofilm while maintaining the electricity output is a challenging topic in microbial fuel cell (MFC) studies. This MFC critical factor becomes more significant when handling with industrial wastewater which normally contains refractory and toxic compounds. This study explores the formation of industrial mixed culture biofilm in chlorophenol cultivated medium through observing and characterizing microscopically its establishment on MFC anode surface. The mixed culture was found to develop its biofilm on the anode surface in the chlorophenol environment and established its maturity and dispersal stages with concurrent electricity generation and phenolic degradation. The mixed culture biofilm engaged the electron transfer roles in MFC by generating current density of 1.4 mA/m2 and removing 53 % of 2,4-dichlorophenol. The results support further research especially on hazardous wastewater treatment using a benign and sustainable method.
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Radiation-hard electrical coil and method for its fabrication
Grieggs, R.J.; Blake, R.D.; Gac, F.D.
1982-06-29
A radiation-hard insulated electrical coil and method for making the same are disclosed. In accordance with the method, a conductor, preferably copper, is wrapped with an aluminum strip and then tightly wound into a coil. The aluminum-wrapped coil is then annealed to relax the conductor in the coiled configuration. The annealed coil is then immersed in an alkaline solution to dissolve the aluminum strip, leaving the bare conductor in a coiled configuration with all of the windings closely packed yet uniformly spaced from one another. The coil is then insulated with a refractory insulating material. In the preferred embodiment, the coil is insulated by coating it with a vitreous enamel and subsequently potting the enamelled coil in a castable ceramic concrete. The resulting coil is substantially insensitive to radiation and may be operated continuously in high radiation environments for long periods of time.
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NASA Astrophysics Data System (ADS)
Zaidan, Shihab A.; Omar, Mustafa H.
2018-05-01
One of the most important requirements for the manufacture of refractory mortars, especially those used in the construction of thermal systems (building or plastering), is the balance between thermal insulation properties and porosity. Where, increasing porosity of mortar to a large amount may be always undesirable, because the absorption of liquid and gases emitted from industrial system is decline the bonded with bricks and structural properties of mortars. Refractory mortars prepared from either fired bauxite or metakaolin clays with different percentages of kaolin (10, 20, 30, and 40 wt%). Bauxite rocks were fired at 1200 °C and metakaolin was obtained by firing kaolin up to 700 °C then crushed and grinded. Grog was added to mixture to reduce the shrinkage. Cylindrical specimens are prepared and then sintered at 1200 °C. All mixtures maintained a low thermal conductivity within the limits of thermal insulation material (less than 0.5 W/m K); it was done by controlling the porosity which reached a maximum value approximately 25%. The volumetric heat capacity and thermal diffusivity was ranged between (1-10 MJ/m3 K), (0.06-0.2 mm2/s), respectively.
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Protective sheath for a continuous measurement thermocouple
Phillippi, R.M.
1991-12-03
Disclosed is a protective thermocouple sheath of a magnesia graphite refractory material for use in continuous temperature measurements of molten metal in a metallurgical ladle and having a basic slag layer thereon. The sheath includes an elongated torpedo-shaped sheath body formed of a refractory composition and having an interior borehole extending axially therethrough and adapted to receive a thermocouple. The sheath body includes a lower end which is closed about the borehole and forms a narrow, tapered tip. The sheath body also includes a first body portion integral with the tapered tip and having a relatively constant cross section and providing a thin wall around the borehole. The sheath body also includes a second body portion having a relatively constant cross section larger than the cross section of the first body portion and providing a thicker wall around the borehole. The borehole terminates in an open end at the second body portion. The tapered tip is adapted to penetrate the slag layer and the thicker second body portion and its magnesia constituent material are adapted to withstand chemical attack thereon from the slag layer. The graphite constituent improves thermal conductivity of the refractory material and, thus, enhances the thermal responsiveness of the device. 4 figures.
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Protective sheath for a continuous measurement thermocouple
Phillippi, R. Michael
1991-01-01
Disclosed is a protective thermocouple sheath of a magnesia graphite refractory material for use in continuous temperature measurements of molten metal in a metallurgical ladle and having a basic slag layer thereon. The sheath includes an elongated torpedo-shaped sheath body formed of a refractory composition and having an interior borehole extending axially therethrough and adapted to receive a thermocouple. The sheath body includes a lower end which is closed about the borehole and forms a narrow, tapered tip. The sheath body also includes a first body portion integral with the tapered tip and having a relatively constant cross section and providing a thin wall around the borehole. The sheath body also includes a second body portion having a relatively constant cross section larger than the cross section of the first body portion and providing a thicker wall around the borehole. The borehole terminates in an open end at the second body portion. The tapered tip is adapted to penetrate the slag layer and the thicker second body portion and its magnesia constituent material are adapted to withstand chemical attack thereon from the slag layer. The graphite constituent improves thermal conductivity of the refractory material and, thus, enhances the thermal responsiveness of the device.
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[Experience of professor FANG Jianqiao treating trigeminal neuralgia at different stages].
Sun, Jing; Fang, Jianqiao; Shao, Xiaomei; Chen, Lifang
2016-02-01
Trigerninal neuralgia is a common refractory disease in clinic. Professor FANG Jianqiao has rich experience through diagnosing and treating the disease for many years. In the first diagnosis, professor FANG underlines the position of damaged neuron and syndrome differentiation. He considers acupuncture should be implemented by stages,namely according to whether the patients are in the period of pain attack, different acupuocture prescriptions are made. Acupuncture manipulation and needle-retention time should be adjusted according to the condition of disease. And the appropriate application of electroacupuncture and transcutaneous electrical acupoint stimulation can strengthen the effect.
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Series II AMTEC cell development issues
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sievers, R.K.; Rasmussen, J.R.; Giglio, J.C.
1998-07-01
The Series II alkali metal thermal to electric converter (AMTEC) cell, developed over the last two year, represents a significant engineering advance in AMTEC technology, and major step toward spacecraft power systems. The PX-5 cell design was developed as an early prototype in stainless steel alloys. This design will evolve into the PX-6 engineering cell and finally into the EPX-1 to be used in the Advanced Radioisotope Power System (ARPS) program. The EPX-1 cell will be all-refractory metal. Late work on the PX-5 and early work on the PX-6 will be described.
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The Use Of Phosphates To Reduce Slag Penetration In Cr203-Based Refractories
Kwong, Kyei-Sing; Dogan, Cynthia P.; Bennett, James P.; Chinn, Richard E.; Petty, Arthur V.
2004-11-09
A high-chromium refractory material that provides improved resistance to coal slag penetration is presented. The refractory mixture comprises a blend of chromium oxide, aluminum oxide and phosphates. The refractory mixture may be blended with an aggregate and cured. In addition a phosphorous oxide may be blended with chromium oxide and aluminum oxide and additionally an aggregate. The refractory mixture reduces the rate of coal slag penetration into the surface of the cured refractory.
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Electromagnetic interference filter for automotive electrical systems
Herron, Nicholas Hayden; Carlson, Douglas S; Tang, David; Korich, Mark D
2013-07-02
A filter for an automotive electrical system includes a substrate having first and second conductive members. First and second input terminals are mounted to the substrate. The first input terminal is electrically connected to the first conductive member, and the second input terminal is electrically connected to the second conductive member. A plurality of capacitors are mounted to the substrate. Each of the capacitors is electrically connected to at least one of the first and second conductive members. First and second power connectors are mounted to the substrate. The first power connector is electrically connected to the first conductive member, and the second power connector is electrically connected to the second conductive member. A common mode choke is coupled to the substrate and arranged such that the common mode choke extends around at least a portion of the substrate and the first and second conductive members.
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Ultrahigh Oxidation Resistance and High Electrical Conductivity in Copper-Silver Powder.
Li, Jiaxiang; Li, Yunping; Wang, Zhongchang; Bian, Huakang; Hou, Yuhang; Wang, Fenglin; Xu, Guofu; Liu, Bin; Liu, Yong
2016-12-22
The electrical conductivity of pure Cu powder is typically deteriorated at elevated temperatures due to the oxidation by forming non-conducting oxides on surface, while enhancing oxidation resistance via alloying is often accompanied by a drastic decline of electrical conductivity. Obtaining Cu powder with both a high electrical conductivity and a high oxidation resistance represents one of the key challenges in developing next-generation electrical transferring powder. Here, we fabricate a Cu-Ag powder with a continuous Ag network along grain boundaries of Cu particles and demonstrate that this new structure can inhibit the preferential oxidation in grain boundaries at elevated temperatures. As a result, the Cu-Ag powder displays considerably high electrical conductivity and high oxidation resistance up to approximately 300 °C, which are markedly higher than that of pure Cu powder. This study paves a new pathway for developing novel Cu powders with much enhanced electrical conductivity and oxidation resistance in service.
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Investigation of the electrical characteristics of electrically conducting yarns and fabrics
NASA Astrophysics Data System (ADS)
Akbarov, R. D.; Baymuratov, B. H.; Akbarov, D. N.; Ilhamova, M.
2017-11-01
Electro-conductive textile materials and products are used presently giving solutions to the problems, related to static electricity, electromagnetic shielding and electromagnetic radiation. Thus a study of their electro-physical characteristics, character of conductivity, possibility of forecasting of electric parameters etc has a substantial value. This work shows the possibility of production electro-conducting textile materials with stable anti-static properties by introduction of electro-conducting yarn into the structure of fabrics. The results of the research, directed to the study of the electro-physical characteristics of electroconducting yarn and fabrics, are influenced by the frequent washing of polyester fabrics containing the different amounts of electro-conducting filaments in the composition. This article reviews the results of the related research, of the electrical characteristics of the yarn and fabric, of the effect of multiple water treatments on the electrical properties of polyester fabrics, containing in their composition different amounts of electrically conductive yarns.
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2018-06-28
Constitutional Mismatch Repair Deficiency Syndrome; Lynch Syndrome; Malignant Glioma; Progressive Ependymoma; Progressive Medulloblastoma; Recurrent Brain Neoplasm; Recurrent Childhood Ependymoma; Recurrent Diffuse Intrinsic Pontine Glioma; Recurrent Medulloblastoma; Refractory Brain Neoplasm; Refractory Diffuse Intrinsic Pontine Glioma; Refractory Ependymoma; Refractory Medulloblastoma
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Evaluation of 2D ceramic matrix composites in aeroconvective environments
NASA Technical Reports Server (NTRS)
Riccitiello, Salvatore R.; Love, Wendell L.; Balter-Peterson, Aliza
1992-01-01
An evaluation is conducted of a novel ceramic-matrix composite (CMC) material system for use in the aeroconvective-heating environments encountered by the nose caps and wing leading edges of such aerospace vehicles as the Space Shuttle, during orbit-insertion and reentry from LEO. These CMCs are composed of an SiC matrix that is reinforced with Nicalon, Nextel, or carbon refractory fibers in a 2D architecture. The test program conducted for the 2D CMCs gave attention to their subsurface oxidation.
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Donor Umbilical Cord Blood Transplant in Treating Patients With Hematologic Cancer
2018-01-17
Acute Lymphoblastic Leukemia; Acute Myeloid Leukemia; Aggressive Non-Hodgkin Lymphoma; Chronic Myelogenous Leukemia, BCR-ABL1 Positive; Chronic Phase Chronic Myelogenous Leukemia, BCR-ABL1 Positive; Indolent Non-Hodgkin Lymphoma; Lymphoma; Mixed Phenotype Acute Leukemia; Myelodysplastic Syndrome; Myeloproliferative Neoplasm; Recurrent Chronic Lymphocytic Leukemia; Recurrent Follicular Lymphoma; Recurrent Lymphoplasmacytic Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Plasma Cell Myeloma; Recurrent Small Lymphocytic Lymphoma; Recurrent T-Cell Non-Hodgkin Lymphoma; Refractory Chronic Lymphocytic Leukemia; Refractory Chronic Myelogenous Leukemia, BCR-ABL1 Positive; Refractory Follicular Lymphoma; Refractory Hodgkin Lymphoma; Refractory Lymphoplasmacytic Lymphoma; Refractory Mantle Cell Lymphoma; Refractory Small Lymphocytic Lymphoma; T-Cell Non-Hodgkin Lymphoma
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Electrical contact arrangement for a coating process
Kabagambe, Benjamin; McCamy, James W; Boyd, Donald W
2013-09-17
A protective coating is applied to the electrically conductive surface of a reflective coating of a solar mirror by biasing a conductive member having a layer of a malleable electrically conductive material, e.g. a paste, against a portion of the conductive surface while moving an electrodepositable coating composition over the conductive surface. The moving of the electrodepositable coating composition over the conductive surface includes moving the solar mirror through a flow curtain of the electrodepositable coating composition and submerging the solar mirror in a pool of the electrodepositable coating composition. The use of the layer of a malleable electrically conductive material between the conductive member and the conductive surface compensates for irregularities in the conductive surface being contacted during the coating process thereby reducing the current density at the electrical contact area.
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Differentiation Therapy With Decitabine in Treating Patients With Myelodysplastic Syndrome
2013-02-25
Chronic Myelomonocytic Leukemia; de Novo Myelodysplastic Syndromes; Myelodysplastic Syndromes; Refractory Anemia; Refractory Anemia With Excess Blasts; Refractory Anemia With Ringed Sideroblasts; Refractory Cytopenia With Multilineage Dysplasia; Thrombocytopenia
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Matsumoto, Hiroaki; Hanayama, Hiroaki; Okada, Takashi; Sakurai, Yasuo; Minami, Hiroaki; Masuda, Atsushi; Tominaga, Shogo; Miyaji, Katsuya; Yamaura, Ikuya; Yoshida, Yasuhisa; Yoshida, Kozo
2017-11-01
Chronic subdural hematoma (CSDH) is sometimes refractory, and this is troublesome for neurosurgeons. Although many studies have reported risk factors or treatments in efforts to prevent recurrence, those have focused on single recurrence, and few cumulative data are available to analyze refractory CSDH. We defined refractory CSDH as ≥2 recurrences, then analyzed and compared clinical factors between patients with single recurrence and those with refractory CSDH in a cohort study, to clarify whether patients with refractory CSDH experience different or more risk factors than patients with single recurrence, and whether burr-hole irrigation with closed-system drainage reduces refractory CSDH. Seventy-five patients had at least 1 recurrence, with single recurrence in 62 patients and ≥2 recurrences in 13 patients. In comparing clinical characteristics, patients with refractory CSDH were significantly younger (P = 0.04) and showed shorter interval to first recurrence (P < 0.001). Organized CSDH was also significantly associated with refractory CSDH (P = 0.02). Multivariate logistic regression analysis identified first recurrence interval <1 month (odds ratio, 6.66, P < 0.001) and age <71 years (odds ratio, 4.16, P < 0.001) as independent risk factors for refractory CSDH. On the other hand, burr-hole irrigation with closed-system drainage did not reduce refractory CSDH. When patients with risk factors for refractory CSDH experience recurrence, alternative surgical procedures may be considered as the second surgery, because burr-hole irrigation with closed-system drainage did not reduce refractory CSDH in our study. Copyright © 2017 Elsevier Inc. All rights reserved.
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Anisotropy of synthetic quartz electrical conductivity at high pressure and temperature
NASA Astrophysics Data System (ADS)
Wang, Duojun; Li, Heping; Yi, Li; Matsuzaki, Takuya; Yoshino, Takashi
2010-09-01
AC measurements of the electrical conductivity of synthetic quartz along various orientations were made between 0.1 and 1 MHz, at ˜855˜1601 K and at 1.0 GPa. In addition, the electrical conductivity of quartz along the c axis has been studied at 1.0-3.0 GPa. The impedance arcs representing bulk conductivity occur in the frequency range of 103-106 Hz, and the electrical responses of the interface between the sample and the electrode occur in the 0.1˜103 Hz range. The pressure has a weak effect on the electrical conductivity. The electrical conductivity experiences no abrupt change near the α - β phase transition point. The electrical conductivity of quartz is highly anisotropic; the electrical conductivity along the c axis is strongest and several orders of magnitude larger than in other directions. The activation enthalpies along various orientations are determined to be 0.6 and 1.2 eV orders of magnitude, respectively. The interpretation of the former is based on the contribution of alkali ions, while the latter effect is attributed to additional unassociated aluminum ions. Comparison of determined anisotropic conductivity of quartz determined with those from field geophysical models shows that the quartz may potentially provide explanations for the behavior of electrical conductivity of anisotropy in the crust that are inferred from the transverse magnetic mode.
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High electric field conduction in low-alkali boroaluminosilicate glass
NASA Astrophysics Data System (ADS)
Dash, Priyanka; Yuan, Mengxue; Gao, Jun; Furman, Eugene; Lanagan, Michael T.
2018-02-01
Electrical conduction in silica-based glasses under a low electric field is dominated by high mobility ions such as sodium, and there is a transition from ionic transport to electronic transport as the electric field exceeds 108 V/m at low temperatures. Electrical conduction under a high electric field was investigated in thin low-alkali boroaluminosilicate glass samples, showing nonlinear conduction with the current density scaling approximately with E1/2, where E is the electric field. In addition, thermally stimulated depolarization current (TSDC) characterization was carried out on room-temperature electrically poled glass samples, and an anomalous discharging current flowing in the same direction as the charging current was observed. High electric field conduction and TSDC results led to the conclusion that Poole-Frenkel based electronic transport occurs in the mobile-cation-depleted region adjacent to the anode, and accounts for the observed anomalous current.
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Capillary zone electrophoresis-mass spectrometer interface
D'Silva, Arthur
1996-08-06
A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conducts is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer.
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Schwamb, Timo; Burg, Brian R; Schirmer, Niklas C; Poulikakos, Dimos
2009-10-07
This paper introduces an electrical four-point measurement method enabling thermal and electrical conductivity measurements of nanoscale materials. The method was applied to determine the thermal and electrical conductivity of reduced graphene oxide flakes. The dielectrophoretically deposited samples exhibited thermal conductivities in the range of 0.14-2.87 W m(-1) K(-1) and electrical conductivities in the range of 6.2 x 10(2)-6.2 x 10(3) Omega(-1) m(-1). The measured properties of each flake were found to be dependent on the duration of the thermal reduction and are in this sense controllable.
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Panattil, Prabitha; Sreelatha, M
2016-09-01
Proteinuria is always associated with intrinsic kidney disese and is a strong predictor of later development of End Stage Renal Disease (ESRD). As Renin Angiotensin Aldosterone System (RAAS) has a role in mediating proteinuria, inhibitors of this system are renoprotective and patients with refractory proteinuria are put on a combination of these agents. The routinely employed triple blockade of RAAS with Angiotensin Converting Enzyme (ACE) inhibitor, ARB and Aldosterone antagonist has many limitations. Addition of Aliskiren to this combination suppresses the RAAS at the earliest stage and can offset many of these limitations. This study was conducted to assess the safety and efficacy of complete RAAS blockade by the addition of Aliskiren in those patients with refractory proteinuria who were already on triple blockade with ACE inhibitor, ARB and Aldosterone antagonist. This study was conducted in Nephrology Department, Calicut Medical College. A total of 36 patients with refractory proteinuria who were already on ACE inhibitor, ARB and Aldosterone antagonist were divided in to two groups A and B. Group A received Aliskiren in addition to the above combination whereas group B continued the same treatment for 12 weeks. Efficacy of the treatment was assessed by recording 24hr urine protein and safety by S.Creatinine, S.Potassium every 2 weeks of the treatment period. Statistical analysis of the lab values was done using SPSS software. Unpaired t-test, Paired t-test and Chi-square test were done for data analysis. Statistical analysis revealed that addition of Aliskiren to the combination therapy with ACE inhibitor+ ARB+ Aldosterone antagonist offers no advantage. But mean reduction in proteinuria was more with Group A than Group B. There is no statistically significant change in S.Creatinine and S.Potassium at the end of treatment. As proteinuria is a strong risk factor for progression to ESRD, even a mild decrease in proteinuria by treatment is renoprotective. Hence treatment with group A may be considered clinically superior to group B with no alteration in safety and tolerability. But further multicentre studies with larger sample size and dose escalation are required for confirmation.
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Masarwa, Reem; Paret, Gideon; Perlman, Amichai; Reif, Shimon; Raccah, Bruria Hirsh; Matok, Ilan
2017-01-05
Vasopressin (AVP) and terlipressin (TP) have been used as last-line therapy in refractory shock in children. However, the efficacy and safety profiles of AVP and TP have not been determined in pediatric refractory shock of different origins. We aimed to assess the efficacy and safety of the addition of AVP/TP therapy in pediatric refractory shock of all causes compared to conventional therapy with fluid resuscitation and vasopressor and inotropic therapy. We conducted a systematic review, meta-analysis, and trial sequential analysis (TSA) comparing AVP and TP to conventional therapy. MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov were searched up to February 2016. The systematic review included all reports of AVP/TP use in the pediatric population. Reports of clinical trials were pooled using random-effects models and TSA. Main outcomes were mortality and tissue ischemia. Three randomized controlled trials and five "before-and-after clinical" trials (without comparator) met the inclusion criteria. Among 224 neonates and children (aged 0 to 18 years) with refractory shock, 152 received therapy with AVP or TP. Pooled analyses showed no association between AVP/TP treatment and mortality (relative risk (RR),1.19; 95% confidence interval (CI), 0.71-2.00), length of stay in the pediatric intensive care unit (PICU) (mean difference (MD), -3.58 days; 95% CI, -9.05 to 1.83), and tissue ischemia (RR, 1.48; 95% CI, 0.47-4.62). In TSA, no significant effect on mortality and risk for developing tissue ischemia was observed with AVP/TP therapy. Our results emphasize the lack of observed benefit for AVP/TP in terms of mortality and length of stay in the PICU, and suggest an increased risk for ischemic events. Our TSA suggests that further large studies are necessary to demonstrate and establish benefits of AVP/TP in children. PROSPERO registry: CRD42016035872.
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Narula, Neeraj; Marshall, John K; Colombel, Jean-Frederic; Leontiadis, Grigorios I; Williams, John G; Muqtadir, Zack; Reinisch, Walter
2016-04-01
Acute severe steroid-refractory ulcerative colitis (UC) carries a poor prognosis and requires optimal management. A systematic review and meta-analysis were conducted to assess cyclosporine and infliximab (IFX) as rescue agents in patients with steroid-refractory UC. A literature search identified studies that investigated IFX and cyclosporine in steroid-refractory UC patients. The primary outcome was short-term response to treatment. Secondary outcomes included the rates of colectomy at 3 months and 12 months, adverse drug reactions, post-operative complications in those who received rescue therapy but underwent colectomy subsequently, and mortality. Odds ratios (ORs) with 95% confidence intervals (CIs) are reported. Overall, 16 studies with 1,473 participants were eligible for inclusion. Among three randomized controlled trials, no significant difference was seen with IFX compared with cyclosporine with regard to treatment response and 3- or 12-month colectomy. Among 13 non-randomized studies, IFX was associated with significantly higher rates of treatment response (OR 2.96 (95% CI 2.12-4.14, χ(2)=6.50, I(2)=0%)) and a lower 12-month colectomy rate (OR 0.42 (95% CI 0.22-0.83, χ(2)=30.94, I(2)=71%)), with no significant difference seen in the 3-month colectomy rate (OR 0.53 (95% CI 0.22-1.28, χ(2)=22.73, I(2)=69%)) compared with cyclosporine. There were no significant differences between IFX and cyclosporine in adverse drug-related events, post-operative complications, or mortality. In the management of steroid-refractory severe UC, no definitive difference between IFX and cyclosporine is demonstrated by randomized trials, but non-randomized studies suggest that IFX is associated with better treatment response and lower risk of colectomy at 12 months. Prospective studies comparing dose-optimized IFX with cyclosporine are needed.
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Electrical condition monitoring method for polymers
Watkins, Jr., Kenneth S.; Morris, Shelby J [Hampton, VA; Masakowski, Daniel D [Worcester, MA; Wong, Ching Ping [Duluth, GA; Luo, Shijian [Boise, ID
2008-08-19
An electrical condition monitoring method utilizes measurement of electrical resistivity of an age sensor made of a conductive matrix or composite disposed in a polymeric structure such as an electrical cable. The conductive matrix comprises a base polymer and conductive filler. The method includes communicating the resistivity to a measuring instrument and correlating resistivity of the conductive matrix of the polymeric structure with resistivity of an accelerated-aged conductive composite.
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Design and development of advanced castable refractory materials
NASA Astrophysics Data System (ADS)
Davis, Robert Bruce
New formulations of castable refractory composite materials were studied. This technology is used to produce low cost composite concrete structures designed for high temperature stability, superior wear resistance and improved strength. An in situ fired, castable cement installation is a heterogeneous structure divided into three zones according to the temperature history and microstructure. The properties of each zone depend on the predominant bonding mode between constituents. Each zone has a characteristic microstructure that influences the integrity of the monolith. The hot side may have a highly dense and developed network of ceramic bonds between constituent particles while the cold side may never reach temperatures sufficient to drive off free water. The thermal, structural and tribological properties depend on the microstructure and the type of bonding that holds the monolith together. The phase distributions are defined by sets of metastable phase conditions driven by the local hydrated chemistry, nearest neighbor oxide compounds, impurities and sintering temperature. Equilibrium phase diagrams were used to select optimum compositions based on higher melting point phases. The phase diagrams were also used to target high temperature phase fields that are stable over wide temperature and stoichiometric ranges. Materials selection of candidate hydraulic clinkers, high temperature oxides, and reinforcement phases were based on requirements for high temperature stability. The calcium aluminate (CaO-Al2O3) and calcium dialuminate (CaO-(Al2O3)2) are common refractory clinkers used in castable refractory cements. The thermodynamics and kinetics of cement hydrate formation are well studied and suited to become the building block of a design for a superior refractory castable cement. The inert oxides mixed with the calcium aluminate clinkers are magnesia (MgO), alumina (Al 2O3), spinel (MgAl2O4) and chromic (Cr2O3). The bulk of the experiments concentrated in the Al2O3--MgO--CaO ternary system. Materials selection criteria for reinforcement materials was based on improved high temperature stability, increased strength, reduced thermal expansion mismatch, low thermal conductivity and increasing wear resistance. The reinforcement phases selected for this investigation are zircon (ZrSiO4), zirconia (ZrO2), spinel (MgAl2O4) and dead burnt magnesia (MgO). Batches of the formulations were tested for thermal conductivity, wear resistance and mechanical strength. Relative rankings of the formulations against commercial products indicate improved or similar performance with increased maximum temperature limits and improved thermal insulating power. The new cement formulations proved to exhibit superior high temperature stability with an increasing volume fraction of high temperature oxides. The addition of reinforcement aggregates and powder sizing to offset the loss of strength. The room temperature compression strength and wear resistance of the optimized formulations exceeded the properties of conventional refractory, brick and castable cement tested concurrently.
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Carbon-Nanotube Conductive Layers for Thin-Film Solar Cells
NASA Technical Reports Server (NTRS)
Landis, Geoffrey A.
2005-01-01
Thin, transparent layers comprising mats of carbon nanotubes have been proposed for providing lateral (that is, inplane) electrical conductivities for collecting electric currents from the front surfaces of the emitter layers of thin-film solar photovoltaic cells. Traditionally, thin, semitransparent films of other electrically conductive materials (usually, indium tin oxide, zinc oxide, or cadmium sulfide) have been used for this purpose. As in the cases of the traditional semitransparent conductive films, the currents collected by the nanotube layers would, in turn, be further collected by front metal contact stripes. Depending on details of a specific solar-cell design, the layer of carbon nanotubes would be deposited in addition to, or instead of, a semitransparent layer of one of these traditional conductive materials (see figure). The proposal is expected to afford the following advantages: The electrical conductivity of the carbon- nanotube layer would exceed that of the corresponding semitransparent layer of traditional electrically conductive material. The greater electrical conductivity of the carbon-nanotube layer would make it possible to retain adequate lateral electrical conductivity while reducing the thickness of, or eliminating entirely, the traditional semitransparent conductive layer. As a consequence of thinning or elimination of the traditional semitransparent conductive layer, less light would be absorbed, so that more of the incident light would be available for photovoltaic conversion. The greater electrical conductivity of the carbon-nanotube layer would make it possible to increase the distance between front metal contact stripes, in addition to (or instead of) thinning or eliminating the layer of traditional semitransparent conductive material. Consequently, the fraction of solar-cell area shadowed by front metal contact stripes would be reduced again, making more of the incident light available for photovoltaic conversion. The electrical conductivities of individual carbon nanotubes can be so high that the mat of carbon nanotubes could be made sparse enough to be adequately transparent while affording adequate lateral electrical conductivity of the mat as a whole. The thickness of the nanotube layer would be chosen so that the layer would contribute significant lateral electrical conductivity, yet would be as nearly transparent as possible to incident light. A typical thickness for satisfying these competing requirements is expected to lie between 50 and 100 nm. The optimum thickness must be calculated by comparing the lateral electrical conductivity, the distance between front metal stripes, and the amount of light lost by absorption in the nanotube layer.
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Electrical conductivity of electrolytes applicable to natural waters from 0 to 100 degrees C
McCleskey, R. Blaine
2011-01-01
The electrical conductivities of 34 electrolyte solutions found in natural waters ranging from (10-4 to 1) molkg-1 in concentration and from (5 to 90) °C have been determined. High-quality electrical conductivity data for numerous electrolytes exist in the scientific literature, but the data do not span the concentration or temperature ranges of many electrolytes in natural waters. Methods for calculating the electrical conductivities of natural waters have incorporated these data from the literature, and as a result these methods cannot be used to reliably calculate the electrical conductivity over a large enough range of temperature and concentration. For the single-electrolyte solutions, empirical equations were developed that relate electrical conductivity to temperature and molality. For the 942 molar conductivity determinations for single electrolytes from this study, the mean relative difference between the calculated and measured values was 0.1 %. The calculated molar conductivity was compared to literature data, and the mean relative difference for 1978 measurements was 0.2 %. These data provide an improved basis for calculating electrical conductivity for most natural waters.
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NASA Astrophysics Data System (ADS)
Kaneko, Tetsuya Kenneth
The penetration rate of molten mineral contents (slag) from spent carbonaceous feedstock into porous ceramic-oxide refractory linings is a critical parameter in determining the lifecycle of integrated gasification combined cycle energy production plants. Refractory linings that withstand longer operation without interruption are desirable because they can mitigate consumable and maintenance costs. Although refractory degradation has been extensively studied for many other high-temperature industrial processes, this work focuses on the mechanisms that are unique to entrained-flow gasification systems. The use of unique feedstock mixtures, temperatures from 1450 °C to 1600 °C, and oxygen partial pressures from 10-7 atm to 10-9 atm pose engineering challenges in designing an optimal refractory material. Experimentation, characterization, and modeling show that gasifier slag infiltration into porous refractory is determined by interactions between the slag and the refractory that either form a physical barrier that impedes fluid flow or induce an increased fluid viscosity that decelerates the velocity of the fluid body. The viscosity of the slag is modified by the thermal profile of the refractory along the penetration direction as well as reactions between the slag and refractory that alter the chemistry, and thereby the thermo-physical properties of the fluid. Infiltration experiments reveal that the temperature gradient inherently present along the refractory lining limits penetration. A refractory in near-isothermal conditions demonstrates deeper slag penetration as compared to one that experiences a steeper thermal profile. The decrease in the local temperatures of the slag as it travels deeper into the refractory increases the viscosity of the fluid, which in turn slows the infiltration velocity of fluid body into the pores of the refractory microstructure. With feedstock mixtures that exhibit high iron-oxide concentrations, a transition-metal-oxide, the oxygen partial pressure of the operating atmosphere regulates the penetration of slag into refractory. The viscosity of the slag, which dictates its penetration rate, is influenced by the oxidation state of the Fe cation. Slag penetrations are shallower in oxidizing conditions than they are in reducing conditions because the iron-oxide from the slag solutions into the corundum-structured refractory and the slag is depleted of iron-oxide, increasing the viscosity of slags. Equally, the chemistries of both the refractory and slag materials dictate the course of penetration. Cr2O3-Al2O3 refractory limits mixed feedstock slag penetration through formation of a chromium spinel layer that functions as a physical obstacle against fluid flow. Al2O 3-SiO2 refractory limits eastern coal feedstock slag penetration as a result of refractory dissolution of SiO2, which increases the viscosity of slags. A physical model, which considers unidirectional fluid flow of slag through each pore of the porous microstructure of the refractory, sufficiently approximates the penetration depth of the slag into the refractory. Agreement between experiments and the physical model demonstrates that the slag is driven into the refractory by capillary pressure. Since the viscosity of the slag continuously changes as the slag travels through the inherent temperature gradient of the refractory lining, the model incorporates dynamic viscosities that are dependent on both temperature and composition to project depths that are unique to the experimental parameters. The significantly different length scales of the radial and penetration directions of the pores allows for the application of a lubrication approximation onto the momentum equation. This process produces an analytical solution that effectively envelopes the variable viscosity into a single term.
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Chen, Fei-Fei; Zhu, Ying-Jie; Xiong, Zhi-Chao; Dong, Li-Ying; Chen, Feng; Lu, Bing-Qiang; Yang, Ri-Long
2017-11-15
How to survive under various harsh working conditions is a key challenge for flexible electronic devices because their performances are always susceptible to environments. Herein, we demonstrate the novel design and fabrication of a new kind of the all-weather flexible electrically conductive paper based on ultralong hydroxyapatite nanowires (HNs) with unique combination of the superhydrophobic surface, electrothermal effect, and flame retardancy. The superhydrophobic surface with water repellency stabilizes the electrically conductive performance of the paper in water. For example, the electrical current through the superhydrophobic paper onto which water droplets are deposited shows a little change (0.38%), and the electrical performance is steady as well even when the paper is immersed in water for 120 s (just 3.65% change). In addition, the intrinsic electrothermal effect of the electrically conductive paper can efficiently heat the paper to reach a high temperature, for example, 224.25 °C, within 10 s. The synergistic effect between the electrothermal effect and superhydrophobic surface accelerates the melting and removal of ice on the heated electrically conductive paper. Deicing efficiency of the heated superhydrophobic electrically conductive paper is ∼4.5 times that of the unheated superhydrophobic electrically conductive paper and ∼10.4 times that of the heated superhydrophilic paper. More importantly, benefiting from fire-resistant ultralong HNs, thermally stable Ketjen black, and Si-O backbone of poly(dimethylsiloxane), we demonstrate the stable and continuous service of the as-prepared electrically conductive paper in the flame for as long as 7 min. The electrical performance of the electrically conductive paper after flame treatment can maintain as high as 90.60% of the original value. The rational design of the electrically conductive paper with suitable building materials and structure demonstrated here will give an inspiration for the development of new kinds of all-weather flexible electronic devices that can work under harsh conditions.
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Ghazikhanlou-Sani, K; Firoozabadi, S M P; Agha-Ghazvini, L; Mahmoodzadeh, H
2016-06-01
There is many ways to assessing the electrical conductivity anisotropy of a tumor. Applying the values of tissue electrical conductivity anisotropy is crucial in numerical modeling of the electric and thermal field distribution in electroporation treatments. This study aims to calculate the tissues electrical conductivity anisotropy in patients with sarcoma tumors using diffusion tensor imaging technique. A total of 3 subjects were involved in this study. All of patients had clinically apparent sarcoma tumors at the extremities. The T1, T2 and DTI images were performed using a 3-Tesla multi-coil, multi-channel MRI system. The fractional anisotropy (FA) maps were performed using the FSL (FMRI software library) software regarding the DTI images. The 3D matrix of the FA maps of each area (tumor, normal soft tissue and bone/s) was reconstructed and the anisotropy matrix was calculated regarding to the FA values. The mean FA values in direction of main axis in sarcoma tumors were ranged between 0.475-0.690. With assumption of isotropy of the electrical conductivity, the FA value of electrical conductivity at each X, Y and Z coordinate axes would be equal to 0.577. The gathered results showed that there is a mean error band of 20% in electrical conductivity, if the electrical conductivity anisotropy not concluded at the calculations. The comparison of FA values showed that there is a significant statistical difference between the mean FA value of tumor and normal soft tissues (P<0.05). DTI is a feasible technique for the assessment of electrical conductivity anisotropy of tissues. It is crucial to quantify the electrical conductivity anisotropy data of tissues for numerical modeling of electroporation treatments.
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2018-05-10
Acute Myeloid Leukemia; Acute Myeloid Leukemia in Remission; Aplastic Anemia; Chronic Myelomonocytic Leukemia; Hodgkin Lymphoma; Indolent Non-Hodgkin Lymphoma; Malignant Neoplasm; Myelodysplastic Syndrome; Myeloproliferative Neoplasm; Plasma Cell Myeloma; Refractory Anemia; Refractory Anemia With Excess Blasts; Refractory Anemia With Ring Sideroblasts; Refractory Cytopenia With Multilineage Dysplasia; Refractory Cytopenia With Multilineage Dysplasia and Ring Sideroblasts
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Improved refractory performance through partnership
DOE Office of Scientific and Technical Information (OSTI.GOV)
Linck, F.E.; Peters, D.
1995-12-31
From the early designs and construction of Circulating Fluidized Bed (CFB) boilers, many improvements have been made based upon observations of performance. Included in these improvements have been the refractory linings. The early refractory linings were subjected to extreme fluctuations in temperatures as the units experienced up and down conditions. As the designs were improved refractory failures were mostly due to the operating conditions and other mechanical stresses rather than continual shutdowns and startups. More recent problems observed with refractory linings are localized areas of high erosion, corrosion and cracking which result in hot spots and eventual shutdowns for repair.more » Today the objective of refractory suppliers and installers is to strive towards planned shutdowns rather than emergency shutdowns. This can be accomplished through partnerships between operations, material suppliers and installers. In essence, the concept is a cooperative effort between these groups to solve the variety of refractory problems in order to achieve longer refractory lining performance and less chance for emergency shutdowns. The reliability of the refractory lining is dependent on the successful combination of the material selected, proper design and the installation of the refractory material. Where these three elements combine, the lining has the best chance of performing its intended purpose.« less
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Grain boundary dominated electrical conductivity in ultrananocrystalline diamond
NASA Astrophysics Data System (ADS)
Wiora, Neda; Mertens, Michael; Brühne, Kai; Fecht, Hans-Jörg; Tran, Ich C.; Willey, Trevor; van Buuren, Anthony; Biener, Jürgen; Lee, Jun-Sik
2017-10-01
N-type electrically conductive ultrananocrystalline diamond (UNCD) films were deposited using the hot filament chemical vapor deposition technique with a gas mixture of H2, CH4 and NH3. Depending on the deposition temperature and ammonia feed gas concentration, which serves as a nitrogen source, room temperature electrical conductivities in the order of 10-2 to 5 × 101 S/cm and activation energies in the meV range were achieved. In order to understand the origin of the enhanced electrical conductivity and clarify the role of ammonia addition to the process gas, a set of UNCD films was grown by systematically varying the ammonia gas phase concentration. These samples were analyzed with respect to their morphology and electrical properties as well as their carbon and nitrogen bonding environments. Temperature dependent electrical conductivity measurements (300-1200 K) show that the electrical conductivity of the samples increases with temperature. The near edge x-ray absorption fine structure measurements reveal that the electrical conductivity of the UNCD films does not correlate directly with ammonia addition, but depends on the total amount of sp2 bonded carbon in the deposited films.
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"Taking Charge of One's Life": A Model for Weight Management Success
ERIC Educational Resources Information Center
Adams, Marlene
2008-01-01
Obesity is a serious, prevalent, and refractory disorder that increases with age particularly in women who enroll in formal weight loss treatments. This study examined the processes used by obese postmenopausal women as they participated in a formal weight loss program. Using grounded theory, interviews were conducted with 14 women engaged in a…
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ERIC Educational Resources Information Center
West, Amy E.; Henry, David B.; Pavuluri, Mani N.
2007-01-01
Objective: The chronic and refractory course of pediatric bipolar disorder merits the study of adjunctive psychosocial interventions designed to facilitate long-term improvements. The objective of this study is to conduct a pilot study of a maintenance model of the child- and family-focused cognitive-behavioral therapy program (CFF-CBT), which…
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Effect of the mechanical deformation on the electrical properties of the polymer/CNT fiber
NASA Astrophysics Data System (ADS)
Cho, Hyun Woo; Sung, Bong June; Nano-Bio Computational Chemistry Laboratory Team
2014-03-01
We elucidate the effect of the mechanical deformation on the electrical properties of the polymer/CNT fiber. The conductive polymer fiber has drawn a great attention for its potential application to a stretchable electronics such as wearable devices and artificial muscles, etc. However, the electrical conductivity of the polymer-based stretchable electronics decreases significantly during the deformation, which may limit the applicability of the polymer/CNT fiber for the stretchable electronics. Moreover, its physical origin for the decrease in electrical conductivity has not been explained clearly. In this work, we employ a coarse-grained model for the polymer/CNT fiber, and we calculate the electric conductivity using global tunneling network (GTN) model. We show that the electric conductivity decreases during the elongation of the polymer/CNT fiber. We also find using critical path approximation (CPA) that the structure of the electrical network of the CNTs changes collectively during the elongation of the fiber, which is strongly responsible for the reduction of the electrical conductivity of the polymer/CNT fiber.
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Hot wire needle probe for thermal conductivity detection
Condie, Keith Glenn; Rempe, Joy Lynn; Knudson, Darrell lee; Daw, Joshua Earl; Wilkins, Steven Curtis; Fox, Brandon S.; Heng, Ban
2015-11-10
An apparatus comprising a needle probe comprising a sheath, a heating element, a temperature sensor, and electrical insulation that allows thermal conductivity to be measured in extreme environments, such as in high-temperature irradiation testing. The heating element is contained within the sheath and is electrically conductive. In an embodiment, the heating element is a wire capable of being joule heated when an electrical current is applied. The temperature sensor is contained within the sheath, electrically insulated from the heating element and the sheath. The electrical insulation electrically insulates the sheath, heating element and temperature sensor. The electrical insulation fills the sheath having electrical resistance capable of preventing electrical conduction between the sheath, heating element, and temperature sensor. The control system is connected to the heating element and the temperature sensor.
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Switching to ranibizumab in diabetic macular oedema refractory to bevacizumab treatment.
Ashraf, M; Souka, A A; Daich Varela, M; El Kayal, H; Schlottmann, P G
2018-05-31
To determine the efficacy of switching to ranibizumab in patients with diabetic macular oedema refractory to treatment with bevacizumab, and to evaluate the outcomes when switching back to bevacizumab. A prospective study was conducted that included 43 eyes of 31 patients refractory to previous bevacizumab treatment. The patients were switched to ranibizumab, and optical coherence tomography was performed one month post-injection. Patients showing improvement (>10% reduction in central sub-field thickness) were switched back to bevacizumab, and optical coherence tomography was performed one month post-switch back. The 34 eyes switched to ranibizumab showed a statistically significant improvement in mean best corrected visual acuity from 0.67±0.39 logMAR to a mean of 0.55±0.36 logMAR (P<.05). In addition, there was a statistically significant decrease in central subfield thickness (CST) from a mean of 475.3±122.8 to a mean of 417.3±109.1 (P<.05). In the 21 eyes that were switched back to bevacizumab, there was no significant difference either in the change in CST or in the change in best corrected visual acuity post-switch back. Switching to ranibizumab in patients improves both the best corrected visual acuity and CST in diabetic patients refractory to previous bevacizumab treatment. This effect is pronounced in patients with increased CST prior to the switch. Switching back to bevacizumab adds no further improvement. Copyright © 2018 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.
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Nagase, Hiroaki; Nishiyama, Masahiro; Nakagawa, Taku; Fujita, Kyoko; Saji, Yohsuke; Maruyama, Azusa
2014-07-01
We conducted a retrospective study to compare the outcome of intravenous midazolam infusion without electroencephalography or targeted temperature management and barbiturate coma therapy with electroencephalography and targeted temperature management for treating convulsive refractory febrile status epilepticus. Of 49 consecutive convulsive refractory febrile status epilepticus patients admitted to the pediatric intensive care unit of our hospital, 29 were excluded because they received other treatments or because of various underlying illnesses. Thus, eight patients were treated with midazolam and 10 with barbiturate coma therapy using thiamylal. Midazolam-treated patients were intubated only when necessary, whereas barbiturate coma therapy patients were routinely intubated. Continuous electroencephalography monitoring was utilized only for the barbiturate coma group. The titration goal for anesthesia was clinical termination of status epilepticus in the midazolam group and suppression or burst-suppression patterns on electroencephalography in the barbiturate coma group. Normothermia was maintained using blankets and neuromuscular blockade in the barbiturate coma group and using antipyretics in the midazolam group. Prognoses were measured at 1 month after onset; children were classified into poor and good outcome groups. Good outcome was achieved in all the barbiturate coma group patients and 50% of the midazolam group patients (P = 0.02, Fisher's exact test). Although the sample size was small and our study could not determine which protocol element is essential for the neurological outcome, the findings suggest that clinical seizure control using midazolam without continuous electroencephalography monitoring or targeted temperature management is insufficient in preventing neurological damage in children with convulsive refractory febrile status epilepticus. Copyright © 2014 Elsevier Inc. All rights reserved.
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Maximum on the Electrical Conductivity Polytherm of Molten TeCl4
NASA Astrophysics Data System (ADS)
Salyulev, Alexander B.; Potapov, Alexei M.
2017-05-01
The electrical conductivity of molten TeCl4 was measured up to 761K, i.e. 106 degrees above the normal boiling point of the salt. For the first time it was found that TeCl4 electrical conductivity polytherm has a maximum. It was recorded at 705K (κmax=0.245 Sm/cm), whereupon the conductivity decreases as the temperature rises. The activation energy of electrical conductivity was calculated.
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Does wastewater from olive mills induce toxicity and water repellency in soil?
NASA Astrophysics Data System (ADS)
Peikert, B.; Bandow, N.; Schaumann, G. E.
2012-04-01
Olive oil mill wastewater is the effluent generated by the olive oil extraction process. It is the main waste product of this industry mainly being produced in the Mediterranean Basin. Because proper treatment options are rare it is often disposed into the environment, e.g. fields or wadies. Due to its high concentration of fatty acids and phytotoxic phenolic compounds and its high chemical and biological oxygen demand, olive oil mill wastewater becomes a serious environmental problem. In this screening study we investigated long-term effects of olive oil mill wastewater application on soil properties in several locations in the West Bank and Israel. We determined wettability via water drop penetration time and the contact angle as well as general soil properties including pH, EC, carbon content, and we conducted thermogravimetrical analyses in order to characterize the impact of the waste water on the quality of soil organic matter. Our results show that application of olive oil mill wastewater has various effects. We determined contact angles between 110 and 120° and water drop penetration times up to 1367 s indicating significant reduction in wettability. Furthermore, soil carbon and nitrogen content and water extractable organic matter increased as well as electric conductivity, which could be pointed out as a fertilizing effect. In contrast soil pH was significantly reduced. Conducting thermal analyses we observed an increase in the labile and refractory carbon fraction. Probably first one is responsible for induced water repellency. As a consequence the reduced wettability negatively affects soil quality. It would therefore be promising to minimize the hydrophobizing impacts without losing fertilizing effects of the olive oil mill wastewater.
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Lau, Dennis H.; Shipp, Nicholas J.; Kelly, Darren J.; Thanigaimani, Shivshankar; Neo, Melissa; Kuklik, Pawel; Lim, Han S.; Zhang, Yuan; Drury, Karen; Wong, Christopher X.; Chia, Nicholas H.; Brooks, Anthony G.; Dimitri, Hany; Saint, David A.; Brown, Lindsay; Sanders, Prashanthan
2013-01-01
Background Both ageing and hypertension are known risk factors for atrial fibrillation (AF) although the pathophysiological contribution or interaction of the individual factors remains poorly understood. Here we aim to delineate the arrhythmogenic atrial substrate in mature spontaneously hypertensive rats (SHR). Methods SHR were studied at 12 and 15 months of age (n = 8 per group) together with equal numbers of age-matched normotensive Wistar-Kyoto control rats (WKY). Electrophysiologic study was performed on superfused isolated right and left atrial preparations using a custom built high-density multiple-electrode array to determine effective refractory periods (ERP), atrial conduction and atrial arrhythmia inducibility. Tissue specimens were harvested for structural analysis. Results Compared to WKY controls, the SHR demonstrated: Higher systolic blood pressure (p<0.0001), bi-atrial enlargement (p<0.05), bi-ventricular hypertrophy (p<0.05), lower atrial ERP (p = 0.008), increased atrial conduction heterogeneity (p = 0.001) and increased atrial interstitial fibrosis (p = 0.006) & CD68-positive macrophages infiltration (p<0.0001). These changes resulted in higher atrial arrhythmia inducibility (p = 0.01) and longer induced AF episodes (p = 0.02) in 15-month old SHR. Ageing contributed to incremental bi-atrial hypertrophy (p<0.01) and atrial conduction heterogeneity (p<0.01) without affecting atrial ERP, fibrosis and arrhythmia inducibility. The limited effect of ageing on the atrial substrate may be secondary to the reduction in CD68-positive macrophages. Conclusions Significant atrial electrical and structural remodeling is evident in the ageing spontaneously hypertensive rat atria. Concomitant hypertension appears to play a greater pathophysiological role than ageing despite their compounding effect on the atrial substrate. Inflammation is pathophysiologically linked to the pro-fibrotic changes in the hypertensive atria. PMID:24013508
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Osadchii, O E
2012-08-01
Endocardial pacing instituted to treat symptomatic bradycardia may nevertheless promote tachyarrhythmia in some pacemaker-implanted patients. We sought to determine the contributing electrophysiological mechanisms. Left ventricular (LV) monophasic action potential duration (APD(90)) and effective refractory periods were determined in perfused guinea-pig hearts along with volume-conducted ECG recordings during epicardial and endocardial stimulations. Consistent with electrotonic modulation of repolarization, APD(90) at a given (either epicardial or endocardial) recording site tended to be longer while pacing from the ipsilateral LV site as compared to stimulations applied at the opposite side of ventricular wall. As a result, the intrinsic transmural repolarization gradient was amplified during endocardial pacing while being significantly reduced upon epicardial stimulations. The maximum slope of APD(90) restitution was greater upon endocardial than epicardial pacing. The excitability was found to recur at earlier repolarization time point at endocardium than epicardium, thereby contributing to increased endocardial critical intervals for re-excitation. Premature extrasystolic beats could have been elicited at shorter coupling stimulation intervals and propagated with greater transmural conduction delay upon endocardial than epicardial stimulations. Endocardial site exhibited lower ventricular fibrillation thresholds and greater inducibility of tachyarrhythmia upon extrasystolic stimulations as compared to epicardium. Arrhythmic susceptibility in guinea-pig heart is greater during endocardial than epicardial pacing because of greater transmural APD(90) dispersion, steeper electrical restitution slopes, greater critical intervals for LV re-excitation and slower transmural conduction of the earliest premature ectopic beats. Further studies are warranted to determine whether these effects may contribute to proarrhythmia in paced human patients. © 2012 The Author Acta Physiologica © 2012 Scandinavian Physiological Society.
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NASA Astrophysics Data System (ADS)
Mehrali, Mohammad; Sadeghinezhad, Emad; Rashidi, Mohammad Mehdi; Akhiani, Amir Reza; Tahan Latibari, Sara; Mehrali, Mehdi; Metselaar, Hendrik Simon Cornelis
2015-06-01
Electrical conductivity is an important property for technological applications of nanofluids that have not been widely investigated, and few studies have been concerned about the electrical conductivity. In this study, nitrogen-doped graphene (NDG) nanofluids were prepared using the two-step method in an aqueous solution of 0.025 wt% Triton X-100 as a surfactant at several concentrations (0.01, 0.02, 0.04, 0.06 wt%). The electrical conductivity of the aqueous NDG nanofluids showed a linear dependence on the concentration and increased up to 1814.96 % for a loading of 0.06 wt% NDG nanosheet. From the experimental data, empirical models were developed to express the electrical conductivity as functions of temperature and concentration. It was observed that increasing the temperature has much greater effect on electrical conductivity enhancement than increasing the NDG nanosheet loading. Additionally, by considering the electrophoresis of the NDG nanosheets, a straightforward electrical conductivity model is established to modulate and understand the experimental results.
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Ultrahigh Oxidation Resistance and High Electrical Conductivity in Copper-Silver Powder
Li, Jiaxiang; Li, Yunping; Wang, Zhongchang; Bian, Huakang; Hou, Yuhang; Wang, Fenglin; Xu, Guofu; Liu, Bin; Liu, Yong
2016-01-01
The electrical conductivity of pure Cu powder is typically deteriorated at elevated temperatures due to the oxidation by forming non-conducting oxides on surface, while enhancing oxidation resistance via alloying is often accompanied by a drastic decline of electrical conductivity. Obtaining Cu powder with both a high electrical conductivity and a high oxidation resistance represents one of the key challenges in developing next-generation electrical transferring powder. Here, we fabricate a Cu-Ag powder with a continuous Ag network along grain boundaries of Cu particles and demonstrate that this new structure can inhibit the preferential oxidation in grain boundaries at elevated temperatures. As a result, the Cu-Ag powder displays considerably high electrical conductivity and high oxidation resistance up to approximately 300 °C, which are markedly higher than that of pure Cu powder. This study paves a new pathway for developing novel Cu powders with much enhanced electrical conductivity and oxidation resistance in service. PMID:28004839
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System and method for evaluating a wire conductor
Panozzo, Edward; Parish, Harold
2013-10-22
A method of evaluating an electrically conductive wire segment having an insulated intermediate portion and non-insulated ends includes passing the insulated portion of the wire segment through an electrically conductive brush. According to the method, an electrical potential is established on the brush by a power source. The method also includes determining a value of electrical current that is conducted through the wire segment by the brush when the potential is established on the brush. The method additionally includes comparing the value of electrical current conducted through the wire segment with a predetermined current value to thereby evaluate the wire segment. A system for evaluating an electrically conductive wire segment is also disclosed.
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Chromia refractory brick with carbon treatment
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bennett, James P.; Kwong, Kyei-Sing
The disclosure provides a refractory brick system comprising a chromia refractory brick for operation in the slagging environment of an air-cooled gasifier. The chromia refractory brick comprises a ceramically-bonded porous chromia refractory having a porosity greater than 9% and having carbon deposits residing within the pores. The brick may be further comprised of Al.sub.2O.sub.3. The air-cooled gasifier generates a liquefied slag in contact with the refractory brick and generally operates at temperatures between 1250.degree. C. and 1575.degree. C. and pressures between 300 psi to 1000 psi, with oxygen partial pressures generally between 10.sup.-4 and 10.sup.-10 atm. The refractory brick performsmore » without substantial chromium carbide or chromium metal formation in the low oxygen partial pressure environment. The inclusion of carbon without chromium carbide formation provides for significant mitigation of slag penetration and significantly reduced refractory wear.« less
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Zheng, Ruiting; Gao, Jinwei; Wang, Jianjian; Chen, Gang
2011-01-01
Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions. PMID:21505445
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Zheng, Ruiting; Gao, Jinwei; Wang, Jianjian; Chen, Gang
2011-01-01
Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions.
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Depositing bulk or micro-scale electrodes
Shah, Kedar G.; Pannu, Satinderpall S.; Tolosa, Vanessa; Tooker, Angela C.; Sheth, Heeral J.; Felix, Sarah H.; Delima, Terri L.
2016-11-01
Thicker electrodes are provided on microelectronic device using thermo-compression bonding. A thin-film electrical conducting layer forms electrical conduits and bulk depositing provides an electrode layer on the thin-film electrical conducting layer. An insulating polymer layer encapsulates the electrically thin-film electrical conducting layer and the electrode layer. Some of the insulating layer is removed to expose the electrode layer.
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Variable Anisotropic Brain Electrical Conductivities in Epileptogenic Foci
Mandelkern, M.; Bui, D.; Salamon, N.; Vinters, H. V.; Mathern, G. W.
2010-01-01
Source localization models assume brain electrical conductivities are isotropic at about 0.33 S/m. These assumptions have not been confirmed ex vivo in humans. This study determined bidirectional electrical conductivities from pediatric epilepsy surgery patients. Electrical conductivities perpendicular and parallel to the pial surface of neocortex and subcortical white matter (n = 15) were measured using the 4-electrode technique and compared with clinical variables. Mean (±SD) electrical conductivities were 0.10 ± 0.01 S/m, and varied by 243% from patient to patient. Perpendicular and parallel conductivities differed by 45%, and the larger values were perpendicular to the pial surface in 47% and parallel in 40% of patients. A perpendicular principal axis was associated with normal, while isotropy and parallel principal axes were linked with epileptogenic lesions by MRI. Electrical conductivities were decreased in patients with cortical dysplasia compared with non-dysplasia etiologies. The electrical conductivity values of freshly excised human brain tissues were approximately 30% of assumed values, varied by over 200% from patient to patient, and had erratic anisotropic and isotropic shapes if the MRI showed a lesion. Understanding brain electrical conductivity and ways to non-invasively measure them are probably necessary to enhance the ability to localize EEG sources from epilepsy surgery patients. PMID:20440549
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Lacosamide-Induced Recurrent Ventricular Tachycardia in the Acute Care Setting.
Berei, Theodore J; Lillyblad, Matthew P; Almquist, Adrian K
2018-04-01
Lacosamide is a new-generation antiepileptic drug (AED) most commonly used adjunctively in the setting of partial-onset seizures refractory to traditional therapy. We describe the first case report, to our knowledge, of a patient who developed recurrent, sustained ventricular tachycardia with multiple administrations of lacosamide in an acute setting. A 70-year-old woman with a history significant for valvular heart disease was admitted to the inpatient cardiology service for worsening heart failure. On hospital day 7, she received a bioprosthetic aortic valve. Prior to surgery and immediately after, the patient's electrocardiogram (ECG) was normal. After developing multiple generalized tonic-clonic seizures refractory to levetiracetam, fosphenytoin, and valproic acid, the decision was made to initiate lacosamide. Two hours following the second lacosamide dose, the patient developed a wide complex QRS that transitioned into sustained ventricular tachycardia requiring electrical cardioversion. Sustained ventricular tachycardia occurred again, just hours after the third dose of lacosamide was given. Following cessation of lacosamide, the patient's QRS interval normalized and has since had no documented episodes of ventricular tachycardia. Clinicians should be aware of the potential for life-threatening rhythmic disturbances in patients initiated on lacosamide and the need for vigilant ECG, electrolyte, and drug-drug monitoring.
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Weaver, Jonathan B; Kumar, Avinash B
2017-02-01
Case report. Operating room. 25YF, ASA IV E who underwent an emergent decompressive craniectomy for refractory intracranial hypertension secondary to acute intracranial hemorhage. A 25Y caucasian female presented with acute intracranial hemorrhage with intraventricular extension secondary to Moya Moya disease. Post admisison, she underwent an emergent decompressive craniectomy for medically refractory intracranial hypertension. Introperatively (post dural closure and bone flap removal) the patient developed acutely worsening peak and plateau pressures followed by pulseless electrical activity necessitating CPR with epinephrine and Vasopressin before return of circulation before return of circulation. Intraoperative TEE done during return of circulation, was essentially non diagnostic, the patient had normal breath sounds throughout, and non-contributory bronchoscopy findings. EKG, arterial blood pressure, heart rate, resp. rate, introperative tranesophageal echocardiogram (TEE), Pulse oximetry, serial arterial blood gases, introperative bronchoscopy, ventilatory peak pressures. A post operative chest CT revealed extensive pneumomediastinum with subcutaneous emphysema. The focussed introperative echocardiogram showed preserved left ventricular function and no evidence of tamponade physiology. Tension pneumomediastinum was the likely etiologic factor for the acute hemodynamic collapse and should be considered in the differential diagnosis of intraoperative circulatory arrest. Copyright © 2016 Elsevier Inc. All rights reserved.
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System design impacts on optimization of the advanced radioisotope power system (ARPS) AMTEC cell
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hendricks, T.J.; Huang, C.
1998-07-01
Several NASA deep space missions require Advanced Radioisotope Power Systems (ARPS) to supply spacecraft power for various internal functions and mission instruments and experiments. AMTEC (Alkali-Metal Thermal-Electric Conversion) power conversion is the DOE-selected technology for an advanced, next- generation RPS to power these spacecraft. Advanced Modular Power Systems, Inc. (AMPS) has begun investigating the design of an AMTEC-based ARPS using the General Purpose Heat Source (GPHS) and the latest PX-5 AMTEC cell technology with refractory materials in critical components. This paper presents and discusses the system design methodology, and results of important system design tradeoffs and system design impacts onmore » the ARPS AMTEC cell design. This work investigated dual 2-GPHS system configurations and 4-GPHS system configurations with 16 side-mounted AMTEC cells operating at beginning-of-mission (BOM) and end-of-mission (EOM) GPHS heat dissipation conditions. Current design studies indicate using a refractory material AMTEC cell with 8-BASE tubes, 5.0 inches long, and 1.75 inches diameter in the 4-GPHS system configuration is the strongest design candidate to satisfy system performance requirements.« less
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NASA Technical Reports Server (NTRS)
Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark; Perusich, Stephen; Whitten, Mary C.; Trejo, David; Zidek, Jason; Sampson, Jeffrey W.;
2009-01-01
Ceramics can be defmed as a material consisting of hard brittle properties produced from inorganic and nonmetallic minerals made by firing at high temperatures. These materials are compounds between metallic and nonmetallic elements and are either totally ionic, or predominately ionic but having some covalent character. This definition allows for a large range of materials, not all applicable to refractory applications. As this report is focused on potential ceramic materials for high temperature, aggressive exposure applications, the ceramics reviewed as part of this report will focus on refractory ceramics specifically designed and used for these applications. Ceramic materials consist of a wide variety of products. Callister (2000) 1 characterized ceramic materials into six classifications: glasses, clay products, refractories, cements, abrasives, and advanced ceramics. Figure 1 shows this classification system. This review will focus mainly on refractory ceramics and cements as in general, the other classifications are neither applicable nor economical for use in large structures such as the flame trench. Although much work has been done in advanced ceramics over the past decade or so, these materials are likely cost prohibitive and would have to be fabricated off-site, transported to the NASA facilities, and installed, which make these even less feasible. Although the authors reviewed the literature on advanced ceramic refractories 2 center dot 3 center dot 4 center dot 5 center dot 6 center dot 7 center dot 8 center dot 9 center dot 10 center dot 11 center dot 12 after the review it was concluded that these materials should not be ' the focus of this report. A review is in progress on materials and systems for prefabricated refractory ceramic panels, but this review is focusing more on typical refractory materials for prefabricated systems, which could make the system more economically feasible. Refractory ceramics are used for a wide variety of applications. Figure 2 shows many ofthese applications, their life expectancy or requirement, and the exposure temperature for the refractory ceramic. Note that the exposure temperatures for refractory ceramics are very similar to the exposure conditions for specialty ceramics (rocket nozzles, space vehicle re-entry fields, etc.) and yet the life expectancy or requirement is relatively low. Currently NASA is repairing the refractory lining in the flame trench after every launch - although this is not a direct indication of low life expectancy, it does indicate that the current system may not be sufficiently durable to maximize economy. Better performing refractory ceramics are needed to improve the performance, economy, and safety during and after launches at the flame trenches at Kennedy Space Center (KSC). To achieve this goal a current study is underway to assess different refractory systems for possible use in the flame trenches at KSC. This report will target the potential applicability of refractory ceramics for use in the flame trenches. An overview of the different refractory ceramics will be provided (see Figure I). This will be followed with a brief description of the structure of refractory products, the properties and characteristics of different systems, the methodology for selecting refractories, and then a general design methodology. Based on these sections, future challenges and opportunities will be identified with the objective of improving the durability, performance, economy, and safety of the launch complex. Refractory ceramics are used for a wide variety of applications. Figure 2 shows many ofthese applications, their life expectancy or requirement, and the exposure temperature for the refractory ceramic. Note that the exposure temperatures for refractory ceramics are very similar to the exposure conditions for specialty ceramics (rocket nozzles, space vehicle re-entry fields, etc.) and yet the life expectancy or requirement is relatively low. Currently NASA is repairing the refractory lining in the flame trench after every launch - although this is not a direct indication of low life expectancy, it does indicate that the current system may not be sufficiently durable to maximize economy. Better performing refractory ceramics are needed to improve the performance, economy, and safety during and after launches at the flame trenches at Kennedy Space Center (KSC). To achieve this goal a current study is underway to assess different refractory systems for possible use in the flame trenches at KSC. This report will target the potential applicability of refractory ceramics for use in the flame trenches. An overview of the different refractory ceramics will be provided (see Figure I). This will be followed with a brief description of the structure of refractory products, the properties and characteristics of different systems, the methodology for selecting refractories, and then a general design methodology. Based on these sections, future challenges and opportunities will be identified with the objective of improving the durability, performance, economy, and safety of the launch complex.
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Coated carbon nanotube array electrodes
Ren, Zhifeng; Wen, Jian; Chen, Jinghua; Huang, Zhongping; Wang, Dezhi
2006-12-12
The present invention provides conductive carbon nanotube (CNT) electrode materials comprising aligned CNT substrates coated with an electrically conducting polymer, and the fabrication of electrodes for use in high performance electrical energy storage devices. In particular, the present invention provides conductive CNTs electrode material whose electrical properties render them especially suitable for use in high efficiency rechargeable batteries. The present invention also provides methods for obtaining surface modified conductive CNT electrode materials comprising an array of individual linear, aligned CNTs having a uniform surface coating of an electrically conductive polymer such as polypyrrole, and their use in electrical energy storage devices.
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Coated carbon nanotube array electrodes
Ren, Zhifeng [Newton, MA; Wen, Jian [Newton, MA; Chen, Jinghua [Chestnut Hill, MA; Huang, Zhongping [Belmont, MA; Wang, Dezhi [Wellesley, MA
2008-10-28
The present invention provides conductive carbon nanotube (CNT) electrode materials comprising aligned CNT substrates coated with an electrically conducting polymer, and the fabrication of electrodes for use in high performance electrical energy storage devices. In particular, the present invention provides conductive CNTs electrode material whose electrical properties render them especially suitable for use in high efficiency rechargeable batteries. The present invention also provides methods for obtaining surface modified conductive CNT electrode materials comprising an array of individual linear, aligned CNTs having a uniform surface coating of an electrically conductive polymer such as polypyrrole, and their use in electrical energy storage devices.
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Grünewald, Volker; Höfner, Klaus; Thon, Walter F.; Kuczyk, Markus A.; Jonas, Udo
1999-01-01
Temporary electrical stimulation using anal or vaginal electrodes and an external pulse generator has been a treatment modality for urinary urge incontinence for nearly three decades. In 1981 Tanagho and Schmidt introduced chronic electrical stimulation of the sacral spinal nerves using a permanently implanted sacral foramen electrode and a battery powered pulse generator for treatment of different kinds of lower urinary tract dysfunction, refractory to conservative treatment. At our department chronic unilateral electrical stimulation of the S3 sacral spinal nerve has been used for treatment of vesi-courethral dysfunction in 43 patients with a mean postoperative follow up of 43,6 months. Lasting symptomatic improvement by more than 50 % could be achieved in 13 of 18 patients with motor urge incontinence (72,2 %) and in 18 of the 21 patients with urinary retention (85,7 %). Implants offer a sustained therapeutic effect to treatment responders, which is not achieved by temporary neuromodulation. Chronic neuromodulation should be predominantly considered in patients with urinary retention. Furthermore in patients with motor urge incontinence, refusing temporary techniques or in those requiring too much effort to achieve a sustained clinical effect. Despite high initial costs chronic sacral neuromodulation is an economically reasonable treatment option in the long run, when comparing it to the more invasive remaining therapeutic alternatives.
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2018-06-25
Adenoid Cystic Carcinoma; Adnexal Carcinoma; Apocrine Carcinoma; Eccrine Porocarcinoma; Extraocular Cutaneous Sebaceous Carcinoma; Hidradenocarcinoma; Keratoacanthoma; Malignant Sweat Gland Neoplasm; Merkel Cell Carcinoma; Microcystic Adnexal Carcinoma; NK-Cell Lymphoma, Unclassifiable; Non-Melanomatous Lesion; Paget Disease; Papillary Adenocarcinoma; Primary Cutaneous Mucinous Carcinoma; Refractory Anaplastic Large Cell Lymphoma; Refractory Mature T-Cell and NK-Cell Non-Hodgkin Lymphoma; Refractory Mycosis Fungoides; Refractory Primary Cutaneous T-Cell Non-Hodgkin Lymphoma; Refractory T-Cell Non-Hodgkin Lymphoma; Sezary Syndrome; Signet Ring Cell Carcinoma; Skin Basal Cell Carcinoma; Skin Basosquamous Cell Carcinoma; Skin Squamous Cell Carcinoma; Spiradenocarcinoma; Squamous Cell Carcinoma of Unknown Primary Origin; Stage III Skin Cancer; Stage IV Skin Cancer; Sweat Gland Carcinoma; Trichilemmocarcinoma; Vulvar Squamous Cell Carcinoma
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Ceramic substrate including thin film multilayer surface conductor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wolf, Joseph Ambrose; Peterson, Kenneth A.
2017-05-09
A ceramic substrate comprises a plurality of ceramic sheets, a plurality of inner conductive layers, a plurality of vias, and an upper conductive layer. The ceramic sheets are stacked one on top of another and include a top ceramic sheet. The inner conductive layers include electrically conductive material that forms electrically conductive features on an upper surface of each ceramic sheet excluding the top ceramic sheet. The vias are formed in each of the ceramic sheets with each via being filled with electrically conductive material. The upper conductive layer includes electrically conductive material that forms electrically conductive features on anmore » upper surface of the top ceramic sheet. The upper conductive layer is constructed from a stack of four sublayers. A first sublayer is formed from titanium. A second sublayer is formed from copper. A third sublayer is formed from platinum. A fourth sublayer is formed from gold.« less
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Estimates of olivine-basaltic melt electrical conductivity using a digital rock physics approach
NASA Astrophysics Data System (ADS)
Miller, Kevin J.; Montési, Laurent G. J.; Zhu, Wen-lu
2015-12-01
Estimates of melt content beneath fast-spreading mid-ocean ridges inferred from magnetotelluric tomography (MT) vary between 0.01 and 0.10. Much of this variation may stem from a lack of understanding of how the grain-scale melt geometry influences the bulk electrical conductivity of a partially molten rock, especially at low melt fraction. We compute bulk electrical conductivity of olivine-basalt aggregates over 0.02 to 0.20 melt fraction by simulating electric current in experimentally obtained partially molten geometries. Olivine-basalt aggregates were synthesized by hot-pressing San Carlos olivine and high-alumina basalt in a solid-medium piston-cylinder apparatus. Run conditions for experimental charges were 1.5 GPa and 1350 °C. Upon completion, charges were quenched and cored. Samples were imaged using synchrotron X-ray micro-computed tomography (μ-CT). The resulting high-resolution, 3-dimensional (3-D) image of the melt distribution constitutes a digital rock sample, on which numerical simulations were conducted to estimate material properties. To compute bulk electrical conductivity, we simulated a direct current measurement by solving the current continuity equation, assuming electrical conductivities for olivine and melt. An application of Ohm's Law yields the bulk electrical conductivity of the partially molten region. The bulk electrical conductivity values for nominally dry materials follow a power-law relationship σbulk = Cσmeltϕm with fit parameters m = 1.3 ± 0.3 and C = 0.66 ± 0.06. Laminar fluid flow simulations were conducted on the same partially molten geometries to obtain permeability, and the respective pathways for electrical current and fluid flow over the same melt geometry were compared. Our results indicate that the pathways for flow fluid are different from those for electric current. Electrical tortuosity is lower than fluid flow tortuosity. The simulation results are compared to existing experimental data, and the potential influence of volatiles and melt films on electrical conductivity of partially molten rocks is discussed.
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Photovoltaic device having light transmitting electrically conductive stacked films
Weber, Michael F.; Tran, Nang T.; Jeffrey, Frank R.; Gilbert, James R.; Aspen, Frank E.
1990-07-10
A light transmitting electrically conductive stacked film, useful as a light transmitting electrode, including a first light transmitting electrically conductive layer, having a first optical thickness, a second light transmitting layer, having a second optical thickness different from the optical thickness of the first layer, and an electrically conductive metallic layer interposed between and in initimate contact with the first and second layers.
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Electric moisture meters for wood
William L. James
1988-01-01
Electric moisture meters for wood measure electric conductance (resistance) or dielectric properties, which vary fairly consistently with moisture content when it is less than 30 percent. The two major classes of electric moisture meters are the conductance (resistance) type and the dielectric type. Conductance-t ype meters use penetrating electrodes that measure in a...
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Simulation of axonal excitability using a Spreadsheet template created in Microsoft Excel.
Brown, A M
2000-08-01
The objective of this present study was to implement an established simulation protocol (A.M. Brown, A methodology for simulating biological systems using Microsoft Excel, Comp. Methods Prog. Biomed. 58 (1999) 181-90) to model axonal excitability. The simulation protocol involves the use of in-cell formulas directly typed into a spreadsheet and does not require any programming skills or use of the macro language. Once the initial spreadsheet template has been set up the simulations described in this paper can be executed with a few simple keystrokes. The model axon contained voltage-gated ion channels that were modeled using Hodgkin Huxley style kinetics. The basic properties of axonal excitability modeled were: (1) threshold of action potential firing, demonstrating that not only are the stimulus amplitude and duration critical in the generation of an action potential, but also the resting membrane potential; (2) refractoriness, the phenomenon of reduced excitability immediately following an action potential. The difference between the absolute refractory period, when no amount of stimulus will elicit an action potential, and relative refractory period, when an action potential may be generated by applying increased stimulus, was demonstrated with regard to the underlying state of the Na(+) and K(+) channels; (3) temporal summation, a process by which two sub-threshold stimuli can unite to elicit an action potential was shown to be due to conductance changes outlasting the first stimulus and summing with the second stimulus-induced conductance changes to drive the membrane potential past threshold; (4) anode break excitation, where membrane hyperpolarization was shown to produce an action potential by removing Na(+) channel inactivation that is present at resting membrane potential. The simulations described in this paper provide insights into mechanisms of axonal excitation that can be carried out by following an easily understood protocol.
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Randomized trial of TAS-102 for refractory metastatic colorectal cancer.
Mayer, Robert J; Van Cutsem, Eric; Falcone, Alfredo; Yoshino, Takayuki; Garcia-Carbonero, Rocio; Mizunuma, Nobuyuki; Yamazaki, Kentaro; Shimada, Yasuhiro; Tabernero, Josep; Komatsu, Yoshito; Sobrero, Alberto; Boucher, Eveline; Peeters, Marc; Tran, Ben; Lenz, Heinz-Josef; Zaniboni, Alberto; Hochster, Howard; Cleary, James M; Prenen, Hans; Benedetti, Fabio; Mizuguchi, Hirokazu; Makris, Lukas; Ito, Masanobu; Ohtsu, Atsushi
2015-05-14
Early clinical trials conducted primarily in Japan have shown that TAS-102, an oral agent that combines trifluridine and tipiracil hydrochloride, was effective in the treatment of refractory colorectal cancer. We conducted a phase 3 trial to further assess the efficacy and safety of TAS-102 in a global population of such patients. In this double-blind study, we randomly assigned 800 patients, in a 2:1 ratio, to receive TAS-102 or placebo. The primary end point was overall survival. The median overall survival improved from 5.3 months with placebo to 7.1 months with TAS-102, and the hazard ratio for death in the TAS-102 group versus the placebo group was 0.68 (95% confidence interval [CI], 0.58 to 0.81; P<0.001). The most frequently observed clinically significant adverse events associated with TAS-102 were neutropenia, which occurred in 38% of those treated, and leukopenia, which occurred in 21%; 4% of the patients who received TAS-102 had febrile neutropenia, and one death related to TAS-102 was reported. The median time to worsening performance status (a change in Eastern Cooperative Oncology Group performance status [on a scale of 0 to 5, with 0 indicating no symptoms and higher numbers indicating increasing degrees of disability] from 0 or 1 to 2 or more) was 5.7 months with TAS-102 versus 4.0 months with placebo (hazard ratio, 0.66; 95% CI, 0.56 to 0.78; P<0.001). In patients with refractory colorectal cancer, TAS-102, as compared with placebo, was associated with a significant improvement in overall survival. (Funded by Taiho Oncology-Taiho Pharmaceutical; RECOURSE ClinicalTrials.gov number, NCT01607957.).
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Ch'ng, Soon W; Brent, Alexander J; Empeslidis, Theodoros; Konidaris, Vasileios; Banerjee, Somnath
2018-06-01
It is hypothesized that using fluocinolone acetonide (FAc) implants such as Iluvien for the treatment of diabetic macular edema (DME) may reduce the total number of intravitreal injections and clinic visits, resulting in an overall treatment cost reduction. The primary aim of this study is to identify the real-world cost savings achievable in a tertiary National Health Service (NHS) hospital. A retrospective cost analysis study was conducted. The inclusion criteria were patients with refractory DME who were switched to Iluvien. The average yearly costs were calculated both before and after the switch to Iluvien. All costs including medicines, investigations, clinics, and management of raised intraocular pressure (IOP) were calculated. The cost differences over the 3 years' worth of Iluvien treatment were calculated and analyzed. To ensure non-inferiority of this treatment intervention, the best corrected visual acuity (BCVA) and central retinal thickness (CRT) were also analyzed. Statistical analysis was conducted with a Student t test where appropriate and statistical significance is identified where p < 0.05. Fourteen eyes of 13 patients met the inclusion criteria. Switching patients to Iluvien achieved on average a saving of £2606.17 per patient (p = 0.33) over the 3 years. However, seven cases (50%) had a rise in IOP after Iluvien that warranted medical treatment and two cases (14.3%) required glaucoma surgery. Incorporating the costs of glaucoma management reduced the overall savings over 3 years to £1064.66 per patient. The BCVA and CRT analysis showed a non-inferiority relationship between Iluvien and any previous treatment. The use of Iluvien in refractory DME patients represents a cost- and time-saving procedure, while showing non-inferiority in terms of efficacy.
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Electrically-Conductive Polyaramid Cable And Fabric
NASA Technical Reports Server (NTRS)
Orban, Ralph F.
1988-01-01
Tows coated with metal provide strength and conductance. Cable suitable for use underwater made of electrically conductive tows of metal-coated polyaramid filaments surrounded by electrically insulating jacket. Conductive tows used to make conductive fabrics. Tension borne by metal-coated filaments, so upon release, entire cable springs back to nearly original length without damage.
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NASA Technical Reports Server (NTRS)
Soltysik, B.; Pawelek, A.; Witkowska, E.
1983-01-01
Phosphate binders, particularly acidic phosphates of Al and Cr, are used for binding Al silicate refractories used for lining of burners, SiC refractories, and refractory mortars. The binders have apparent d. 2.13-2.18 g/cu cm, porosity 21.4-23.8%, compressive strength 223 71 kg/ sq cm, total shrinkage 0.2-0.8%, and refractoriness 1240 deg.
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Refractory inclusions in the Ornans C30 chondrite
NASA Technical Reports Server (NTRS)
Davis, A. M.
1985-01-01
Several types of metedorites contain unusual objects 10 micrometers to 2 centimeters across that are enriched in refractory elements such as calcium, aluminum and titanium. These objects, commonly known as refractory inclusions, are most abundant in the meteorites known as carbonaceous chondrites. The refractory inclusions that have been found in the Ornans metedorite, a member of a little-studied group of carbonaceous chondrites are described. Some refractory inclusions in Ornans resemble those found in other meteorites, while others are unlike any seen before. The unusual inclusions in Ornans contain minerals with extraordinary enrichments in highly refractory elements.
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NASA Astrophysics Data System (ADS)
Sharma, Nidhi; Khan, Zahid A.; Siddiquee, Arshad Noor; Shihab, Suha K.; Atif Wahid, Mohd
2018-04-01
Copper (Cu) is predominantly used material as a conducting element in electrical and electronic components due to its high conductivity. Aluminum (Al) being lighter in weight and more conductive on weight basis than that of Cu is able to replace or partially replace Cu to make lighter and cost effective electrical components. Conventional methods of joining Al to Cu, such as, fusion welding process have many shortcomings. Friction Stir Welding (FSW) is a solid state welding process which overcomes the shortcoming of the fusion welding. FSW parameters affect the mechanical and electrical properties of the joint. This study aims to evaluate the effect of different process parameters such as shoulder diameter, pin offset, welding and rotational speed on the microstructure and electrical conductivity of the dissimilar Al-Cu joint. FSW is performed using cylindrical pin profile, and four process parameters. Each parameter at different levels is varied according to Taguchi’s L18 standard orthogonal array. It is found that the electrical conductivity of the FSWed joints are equal to that of aluminum at all the welded sections. FSW is found to be an effective technique to join Al to Cu without compromising with the electrical properties. However, the electrical conductivity gets influenced by the process parameters in the stir zone. The optimal combination of the FSW parameters for maximum electrical conductivity is determined. The analysis of variance (ANOVA) technique applied on stir zone suggests that the rotational speed and tool pin offset are the significant parameters to influence the electrical conductivity.
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Minimizing radiation damage in nonlinear optical crystals
Cooke, D.W.; Bennett, B.L.; Cockroft, N.J.
1998-09-08
Methods are disclosed for minimizing laser induced damage to nonlinear crystals, such as KTP crystals, involving various means for electrically grounding the crystals in order to diffuse electrical discharges within the crystals caused by the incident laser beam. In certain embodiments, electrically conductive material is deposited onto or into surfaces of the nonlinear crystals and the electrically conductive surfaces are connected to an electrical ground. To minimize electrical discharges on crystal surfaces that are not covered by the grounded electrically conductive material, a vacuum may be created around the nonlinear crystal. 5 figs.
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NASA Astrophysics Data System (ADS)
El-Nahass, M. M.; Attia, A. A.; Ali, H. A. M.; Salem, G. F.; Ismail, M. I.
2018-02-01
The structural characteristics of thermally deposited ZnIn2Se4 thin films were indexed utilizing x-ray diffraction as well as scanning electron microscopy techniques. Dielectric properties, electric modulus and AC electrical conductivity of ZnIn2Se4 thin films were examined in the frequency range from 42 Hz to 106 Hz. The capacitance, conductance and impedance were measured at different temperatures. The dielectric constant and dielectric loss decrease with an increase in frequency. The maximum barrier height was determined from the analysis of the dielectric loss depending on the Giuntini model. The real part of the electric modulus revealed a constant maximum value at higher frequencies and the imaginary part of the electric modulus was characterized by the appearance of dielectric relaxation peaks. The AC electrical conductivity obeyed the Jonscher universal power law. Correlated barrier hopping model was the appropriate mechanism for AC conduction in ZnIn2Se4 thin films. Estimation of the density of states at the Fermi level and activation energy, for AC conduction, was carried out based on the temperature dependence of AC electrical conductivity.
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Grain boundary dominated electrical conductivity in ultrananocrystalline diamond
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wiora, Neda; Mertens, Michael; Bruhne, Kai
Here, N-type electrically conductive ultrananocrystalline diamond (UNCD) films were deposited using the hot filament chemical vapor deposition technique with a gas mixture of H 2, CH 4 and NH 3. Depending on the deposition temperature and ammonia feed gas concentration, which serves as a nitrogen source, room temperature electrical conductivities in the order of 10 –2 to 5 × 10 1S/cm and activation energies in the meV range were achieved. In order to understand the origin of the enhanced electrical conductivity and clarify the role of ammonia addition to the process gas, a set of UNCD films was grown bymore » systematically varying the ammonia gas phase concentration. These samples were analyzed with respect to their morphology and electrical properties as well as their carbon and nitrogen bonding environments. Temperature dependent electrical conductivity measurements (300–1200 K) show that the electrical conductivity of the samples increases with temperature. The near edge x-ray absorption fine structure measurements reveal that the electrical conductivity of the UNCD films does not correlate directly with ammonia addition, but depends on the total amount of sp2 bonded carbon in the deposited films.« less
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Grain boundary dominated electrical conductivity in ultrananocrystalline diamond
Wiora, Neda; Mertens, Michael; Bruhne, Kai; ...
2017-10-09
Here, N-type electrically conductive ultrananocrystalline diamond (UNCD) films were deposited using the hot filament chemical vapor deposition technique with a gas mixture of H 2, CH 4 and NH 3. Depending on the deposition temperature and ammonia feed gas concentration, which serves as a nitrogen source, room temperature electrical conductivities in the order of 10 –2 to 5 × 10 1S/cm and activation energies in the meV range were achieved. In order to understand the origin of the enhanced electrical conductivity and clarify the role of ammonia addition to the process gas, a set of UNCD films was grown bymore » systematically varying the ammonia gas phase concentration. These samples were analyzed with respect to their morphology and electrical properties as well as their carbon and nitrogen bonding environments. Temperature dependent electrical conductivity measurements (300–1200 K) show that the electrical conductivity of the samples increases with temperature. The near edge x-ray absorption fine structure measurements reveal that the electrical conductivity of the UNCD films does not correlate directly with ammonia addition, but depends on the total amount of sp2 bonded carbon in the deposited films.« less
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Gasket Assembly for Sealing Mating Surfaces
NASA Technical Reports Server (NTRS)
Bryant, Melvin A., III (Inventor)
2003-01-01
A pair of substantially opposed mating surfaces are joined to each other and sealed in place by means of an electrically-conductive member which is placed in proximity to the mating surfaces. The electrically-conductive member has at least one element secured thereto which is positioned to contact the mating surfaces, and which softens when the electrically-conductive member is heated by passing an electric current therethrough. The softened element conforms to the mating surfaces, and upon cooling of the softened element the mating surfaces are joined together in an effective seal. Of particular significance is an embodiment of the electrically-conductive member which is a gasket having an electrically-conductive gasket base and a pair of the elements secured to opposite sides of the gasket base. This embodiment is positioned between the opposed mating surfaces to be joined to each other. Also significant is an embodiment of the electrically-conductive member which is an electrically-conductive sleeve having an element secured to its inner surface. This embodiment surrounds cylindrical members the bases of which are the substantially opposed mating surfaces to be joined, and the element on the inner surface of the sleeve contacts the outer surfaces of the cylindrical members.
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van de Kamp, Cornelis; Gawthrop, Peter J.; Gollee, Henrik; Loram, Ian D.
2013-01-01
Researchers have previously adopted the double stimulus paradigm to study refractoriness in human neuromotor control. Currently, refractoriness, such as the Psychological Refractory Period (PRP) has only been quantified in discrete movement conditions. Whether refractoriness and the associated serial ballistic hypothesis generalises to sustained control tasks has remained open for more than sixty years. Recently, a method of analysis has been presented that quantifies refractoriness in sustained control tasks and discriminates intermittent (serial ballistic) from continuous control. Following our recent demonstration that continuous control of an unstable second order system (i.e. balancing a ‘virtual’ inverted pendulum through a joystick interface) is unnecessary, we ask whether refractoriness of substantial duration (∼200 ms) is evident in sustained visual-manual control of external systems. We ask whether the refractory duration (i) is physiologically intrinsic, (ii) depends upon system properties like the order (0, 1st, and 2nd) or stability, (iii) depends upon target jump direction (reversal, same direction). Thirteen participants used discrete movements (zero order system) as well as more sustained control activity (1st and 2nd order systems) to track unpredictable step-sequence targets. Results show a substantial refractory duration that depends upon system order (250, 350 and 550 ms for 0, 1st and 2nd order respectively, n = 13, p<0.05), but not stability. In sustained control refractoriness was only found when the target reverses direction. In the presence of time varying actuators, systems and constraints, we propose that central refractoriness is an appropriate control mechanism for accommodating online optimization delays within the neural circuitry including the more variable processing times of higher order (complex) input-output relations. PMID:23300430
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NASA Astrophysics Data System (ADS)
Dong, Song-Tao; Zhang, Bin-Bin; Xiong, Ye; Lv, Yang-Yang; Yao, Shu-Hua; Chen, Y. B.; Zhou, Jian; Zhang, Shan-Tao; Chen, Yan-Feng
2015-09-01
Bi2AE2Co2O8+δ (AE represents alkaline earth), constructed by stacking of rock-salt Bi2AE2O4 and triangle CoO2 layers alternatively along c-axis, is one of promising thermoelectric oxides. The most impressive feature of Bi2AE2Co2O8+δ, as reported previously, is their electrical conductivity mainly lying along CoO2 plane, adjusting Bi2AE2O4 layer simultaneously manipulates both thermal conductivity and electrical conductivity. It in turn optimizes thermoelectric performance of these materials. In this work, we characterize the anisotropic thermal and electrical conductivity along both ab-plane and c-direction of Bi2AE2Co2O8+δ (AE = Ca, Sr, Ba, Sr1-xBax) single crystals. The results substantiate that isovalence replacement in Bi2AE2Co2O8+δ remarkably modifies their electrical property along ab-plane; while their thermal conductivity along ab-plane only has a slightly difference. At the same time, both the electrical conductivity and thermal conductivity along c-axis of these materials also have dramatic changes. Certainly, the electrical resistance along c-axis is too high to be used as thermoelectric applications. These results suggest that adjusting nano-block Bi2AE2O4 layer in Bi2AE2Co2O8+δ cannot modify the thermal conductivity along high electrical conductivity plane (ab-plane here). The evolution of electrical property is discussed by Anderson localization and electron-electron interaction U. And the modification of thermal conductivity along c-axis is attributed to the microstructure difference. This work sheds more light on the manipulation of the thermal and electrical conductivity in the layered thermoelectric materials.
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2018-03-28
Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative; Chronic Myelomonocytic Leukemia; de Novo Myelodysplastic Syndrome; Essential Thrombocythemia; Myeloproliferative Neoplasm; Paroxysmal Nocturnal Hemoglobinuria; Polycythemia Vera; Polycythemia Vera, Post-Polycythemic Myelofibrosis Phase; Primary Myelofibrosis; Refractory Anemia; Refractory Anemia With Excess Blasts; Refractory Anemia With Ring Sideroblasts; Refractory Cytopenia With Multilineage Dysplasia; Refractory Cytopenia With Multilineage Dysplasia and Ring Sideroblasts
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2018-04-23
Grade 3a Follicular Lymphoma; Grade 3b Follicular Lymphoma; Recurrent Classical Hodgkin Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Follicular Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Mediastinal (Thymic) Large B-Cell Cell Lymphoma; Refractory Classical Hodgkin Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Follicular Lymphoma; Refractory Mediastinal (Thymic) Large B-Cell Cell Lymphoma
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Effect of a hawthorn extract on contraction and energy turnover of isolated rat cardiomyocytes.
Pöpping, S; Rose, H; Ionescu, I; Fischer, Y; Kammermeier, H
1995-11-01
The hawthorn extract LI 132 (crataegus), prepared from leaves and flowers, and standardised to 2.2% flavonoids, was investigated with respect to its effect on (1) the contraction, (2) the energy-turnover and (3) the apparent refractory period (t(ref)) of isolated cardiac myocytes from adult rats. (1) The contractile behaviour of attached myocytes was analyzed by an image processing system. (2) The energy turnover was calculated from the decrease in oxygen content in the myocyte suspension, brought about by cellular respiration. It was differentiated between energy turnover related to cell shortening and that required for ionic transport processes by application of the contraction-inhibiting agent 2,3-butanedione monoxime. (3) The apparent refractory period (t(ref)) was evaluated by pacing the myocytes with increasing stimulation rates and determining the frequency at which failure of single contractions occurred. For these purposes, the myocytes were incubated in a stimulation chamber, which is part of a computer-assisted system allowing to simultaneously evaluate the mechanics and energetics of electrically induced contraction. Within a range of 30-180 microg/ml, the hawthorn extract exhibited a positive inotropic effect on the contraction amplitude accompanied by a moderate increase of energy turnover both for mechanical and ionic processes. In comparison with other positive inotropic interventions, such as application of the beta-adrenergic agonist isoprenaline, or of the cardiac glycoside ouabain (g-strophantin), or elevation of the extracellular Ca++-concentration, the effects of the hawthorn extract were significantly more economical with respect to the energetics of the myocytes. Furthermore the extract prolonged the apparent refractory period in the presence and the absence of isoprenaline, which be indicative for an antiarrhythmic potential.
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Electrically conductive material
Singh, Jitendra P.; Bosak, Andrea L.; McPheeters, Charles C.; Dees, Dennis W.
1993-01-01
An electrically conductive material for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO.sub.2 as a matrix and 6-19 wt. % monoclinic ZrO.sub.2 formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO.sub.2 as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns.
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Contact-independent electrical conductance measurement
Mentzel, Tamar S.; MacLean, Kenneth; Kastner, Marc A.; Ray, Nirat
2017-01-24
Electrical conductance measurement system including a one-dimensional semiconducting channel, with electrical conductance sensitive to electrostatic fluctuations, in a circuit for measuring channel electrical current. An electrically-conductive element is disposed at a location at which the element is capacitively coupled to the channel; a midpoint of the element aligned with about a midpoint of the channel, and connected to first and second electrically-conductive contact pads that are together in a circuit connected to apply a changing voltage across the element. The electrically-conductive contact pads are laterally spaced from the midpoint of the element by a distance of at least about three times a screening length of the element, given in SI units as (K.di-elect cons..sub.0/e.sup.2D(E.sub.F)).sup.1/2, where K is the static dielectric constant, .di-elect cons..sub.0 is the permittivity of free space, e is electron charge, and D(E.sub.F) is the density of states at the Fermi energy for the element.
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Lenalidomide and Blinatumomab in Treating Patients With Relapsed Non-Hodgkin Lymphoma
2018-06-11
CD19 Positive; Mediastinal Lymphoma; Recurrent B-Cell Lymphoma, Unclassifiable, With Features Intermediate Between Diffuse Large B-Cell Lymphoma and Classic Hodgkin Lymphoma; Recurrent Burkitt Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Non-Hodgkin Lymphoma; Recurrent Small Lymphocytic Lymphoma; Refractory B-Cell Lymphoma, Unclassifiable, With Features Intermediate Between Diffuse Large B-Cell Lymphoma and Classic Hodgkin Lymphoma; Refractory Burkitt Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Follicular Lymphoma; Refractory Mantle Cell Lymphoma; Refractory Small Lymphocytic Lymphoma
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Evaluation of Alternative Refractory Materials for the Main Flame Deflectors at KSC Launch Complexes
NASA Technical Reports Server (NTRS)
Calle, Luz Marina; Trejo, David; Rutkowsky, Justin
2006-01-01
The deterioration of the refractory materials used to protect the KSC launch complex steel base structures from the high temperatures during launches results in frequent and costly repairs and safety hazards. KSC-SPEC-P-0012, Specification for Refractory Concrete, is ineffective in qualifying refractory materials. This study of the specification and of alternative refractory materials recommends a complete revision of the specification and further investigation of materials that were found to withstand the environment of the Solid Rocket Booster main flame deflector better than the refractory materials in current use in terms of compressive strength, tensile strength, modulus of rupture, shrinkage, and abrasion.
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Transient liquid phase ceramic bonding
Glaeser, Andreas M.
1994-01-01
Ceramics are joined to themselves or to metals using a transient liquid phase method employing three layers, one of which is a refractory metal, ceramic or alloy. The refractory layer is placed between two metal layers, each of which has a lower melting point than the refractory layer. The three layers are pressed between the two articles to be bonded to form an assembly. The assembly is heated to a bonding temperature at which the refractory layer remains solid, but the two metal layers melt to form a liquid. The refractory layer reacts with the surrounding liquid and a single solid bonding layer is eventually formed. The layers may be designed to react completely with each other and form refractory intermetallic bonding layers. Impurities incorporated into the refractory metal may react with the metal layers to form refractory compounds. Another method for joining ceramic articles employs a ceramic interlayer sandwiched between two metal layers. In alternative embodiments, the metal layers may include sublayers. A method is also provided for joining two ceramic articles using a single interlayer. An alternate bonding method provides a refractory-metal oxide interlayer placed adjacent to a strong oxide former. Aluminum or aluminum alloys are joined together using metal interlayers.
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Defining refractory migraine: results of the RHSIS Survey of American Headache Society members.
Schulman, Elliott A; Peterlin, B Lee; Lake, Alvin E; Lipton, Richard B; Hanlon, Alexandra; Siegel, Sherry; Levin, Morris; Goadsby, Peter J; Markley, Herbert G
2009-04-01
To gauge consensus regarding a proposed definition for refractory migraine proposed by Refractory Headache Special Interest Section, and where its use would be most appropriate. Headache experts have long recognized that a subgroup of headache sufferers remains refractory to treatment. Although different groups have proposed criteria to define refractory migraine, the definition remains controversial. The Refractory Headache Special Interest Section of the American Headache Society developed a definition through a consensus process, assisted by a literature review and initial membership survey. A 12-item questionnaire was distributed at the American Headache Society meeting in 2007 during a platform session and at the Refractory Headache Special Interest Section symposium. The same questionnaire was subsequently sent to all American Headache Society members via e-mail. A total of 151 responses from AHS members form the basis of this report. The survey instrument was designed using Survey Monkey. Frequencies and percentages of the survey were used to describe survey responses. American Headache Society members agreed that a definition for refractory migraine is needed (91%) that it should be added to the International Classification of Headache Disorders-2 (86%), and that refractory forms of non-migraine headache disorders should be defined (87%). Responders believed a refractory migraine definition would be of greatest value in selecting patients for clinical drug trials. The current refractory migraine definition requires a diagnosis of migraine, interference with function or quality of life despite modification of lifestyle factors, and adequate trials of acute and preventive medicines with established efficacy. The proposed criteria for the refractory migraine definition require failing 2 preventive medications to meet the threshold for failure. Although 42% of respondents agreed with the working definition of refractory migraine, 43% favored increasing the number to 3 (50%) or 4 (26%) preventive treatment failures. When respondents were asked if they felt that the proposed definition was appropriate to select patients for invasive procedures (patent foramen ovale repair or stimulators) only 44% agreed. There is a consensus for a need for a definition for refractory migraine and that it should be added to the International Classification of Headache Disorder-2. There was also general agreement by the responders that refractory forms of non-migraine headache disorders should be defined.
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Dual-Task Processing When Task 1 Is Hard and Task 2 Is Easy: Reversed Central Processing Order?
ERIC Educational Resources Information Center
Leonhard, Tanja; Fernandez, Susana Ruiz; Ulrich, Rolf; Miller, Jeff
2011-01-01
Five psychological refractory period (PRP) experiments were conducted with an especially time-consuming first task (Experiments 1, 3, and 5: mental rotation; Experiments 2 and 4: memory scanning) and with equal emphasis on the first task and on the second (left-right tone judgment). The standard design with varying stimulus onset asynchronies…
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Intravesical NGF Antisense Therapy Using Lipid Nanoparticle for Interstitial Cystitis
2015-10-01
intravesical botulinum toxin type A injec- tions plus hydrodistention with hydrodis- tention alone for the treatment of refractory interstitial cystitis/ painful ...SUPPLEMENTARY NOTES 14. ABSTRACT Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating disorder characterized by persistent pelvic pain ...from an animal efficacy experiment conducted during the previous period. The project is ongoing. 15. SUBJECT TERMS Interstitial cystitis/ painful
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Conducting single-molecule magnet materials.
Cosquer, Goulven; Shen, Yongbing; Almeida, Manuel; Yamashita, Masahiro
2018-05-11
Multifunctional molecular materials exhibiting electrical conductivity and single-molecule magnet (SMM) behaviour are particularly attractive for electronic devices and related applications owing to the interaction between electronic conduction and magnetization of unimolecular units. The preparation of such materials remains a challenge that has been pursued by a bi-component approach of combination of SMM cationic (or anionic) units with conducting networks made of partially oxidized (or reduced) donor (or acceptor) molecules. The present status of the research concerning the preparation of molecular materials exhibiting SMM behaviour and electrical conductivity is reviewed, describing the few molecular compounds where both SMM properties and electrical conductivity have been observed. The evolution of this research field through the years is discussed. The first reported compounds are semiconductors in spite being able to present relatively high electrical conductivity, and the SMM behaviour is observed at low temperatures where the electrical conductivity of the materials is similar to that of an insulator. During the recent years, a breakthrough has been achieved with the coexistence of high electrical conductivity and SMM behaviour in a molecular compound at the same temperature range, but so far without evidence of a synergy between these properties. The combination of high electrical conductivity with SMM behaviour requires not only SMM units but also the regular and as far as possible uniform packing of partially oxidized molecules, which are able to provide a conducting network.
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The electrical conductivity of in vivo human uterine fibroids.
DeLonzor, Russ; Spero, Richard K; Williams, Joseph J
2011-01-01
The purpose of this study was to determine the value of electrical conductivity that can be used for numerical modelling in vivo radiofrequency ablation (RFA) treatments of human uterine fibroids. No experimental electrical conductivity data have previously been reported for human uterine fibroids. In this study electrical data (voltage) from selected in vivo clinical procedures on human uterine fibroids were used to numerically model the treatments. Measured versus calculated power dissipation profiles were compared to determine uterine fibroid electrical conductivity. Numerical simulations were conducted utilising a wide range of values for tissue thermal conductivity, heat capacity and blood perfusion coefficient. The simulations demonstrated that power dissipation was insensitive to the exact values of these parameters for the simulated geometry, treatment duration, and power level. Consequently, it was possible to determine tissue electrical conductivity without precise knowledge of the values for these parameters. Results of this study showed that an electrical conductivity for uterine fibroids of 0.305 S/m at 37°C and a temperature coefficient of 0.2%/°C can be used for modelling Radio Frequency Ablation of human uterine fibroids at a frequency of 460 kHz for temperatures from 37°C to 100°C.
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Characterization studies of prototype ISOL targets for the RIA
NASA Astrophysics Data System (ADS)
Greene, John P.; Burtseva, Tatiana; Neubauer, Janelle; Nolen, Jerry A.; Villari, Antonio C. C.; Gomes, Itacil C.
2005-12-01
Targets employing refractory compounds are being developed for the rare isotope accelerator (RIA) facility to produce ion species far from stability. With the 100 kW beams proposed for the production targets, dissipation of heat becomes a challenging issue. In our two-step target design, neutrons are generated in a refractory primary target, inducing fission in the surrounding uranium carbide. The interplay of density, grain size, thermal conductivity and diffusion properties of the UC2 needs to be well understood before fabrication. Thin samples of uranium carbide were prepared for thermal conductivity measurements using an electron beam to heat the sample and an optical pyrometer to observe the thermal radiation. Release efficiencies and independent thermal analysis on these samples are being undertaken at Oak Ridge National Laboratory (ORNL). An alternate target concept for RIA, the tilted slab approach promises to be simple with fast ion release and capable of withstanding high beam intensities while providing considerable yields via spallation. A proposed small business innovative research (SBIR) project will design a prototype tilted target, exploring the materials needed for fabrication and testing at an irradiation facility to address issues of heat transfer and stresses within the target.
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Examination of nanosecond laser melting thresholds in refractory metals by shear wave acoustics
NASA Astrophysics Data System (ADS)
Abdullaev, A.; Muminov, B.; Rakhymzhanov, A.; Mynbayev, N.; Utegulov, Z. N.
2017-07-01
Nanosecond laser pulse-induced melting thresholds in refractory (Nb, Mo, Ta and W) metals are measured using detected laser-generated acoustic shear waves. Obtained melting threshold values were found to be scaled with corresponding melting point temperatures of investigated materials displaying dissimilar shearing behavior. The experiments were conducted with motorized control of the incident laser pulse energies with small and uniform energy increments to reach high measurement accuracy and real-time monitoring of the epicentral acoustic waveforms from the opposite side of irradiated sample plates. Measured results were found to be in good agreement with numerical finite element model solving coupled elastodynamic and thermal conduction governing equations on structured quadrilateral mesh. Solid-melt phase transition was handled by means of apparent heat capacity method. The onset of melting was attributed to vanished shear modulus and rapid radial molten pool propagation within laser-heated metal leading to preferential generation of transverse acoustic waves from sources surrounding the molten mass resulting in the delay of shear wave transit times. Developed laser-based technique aims for applications involving remote examination of rapid melting processes of materials present in harsh environment (e.g. spent nuclear fuels) with high spatio-temporal resolution.
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Understanding refractory failures
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bases, G.J.
2006-01-15
Compared to most pieces of a power plant, refractory costs very little to install. Yet, if improperly manufactured, specified, stored, mixed installed, cured, or dried, refractory may cause problems that can significantly decrease a plant's operating efficiency and flexibility. Like Rodney Dangerfield, refractory design and installation deserve more respect. 4 photos.
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2018-05-22
Lymphocyte-Rich Classical Hodgkin Lymphoma; Recurrent Lymphocyte-Depleted Classical Hodgkin Lymphoma; Recurrent Mixed Cellularity Classical Hodgkin Lymphoma; Recurrent Nodular Sclerosis Classical Hodgkin Lymphoma; Refractory Lymphocyte-Depleted Classical Hodgkin Lymphoma; Refractory Mixed Cellularity Classical Hodgkin Lymphoma; Refractory Nodular Sclerosis Classical Hodgkin Lymphoma
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2017-11-15
Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Hodgkin Lymphoma; Recurrent T-Cell Non-Hodgkin Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Hodgkin Lymphoma; Refractory T-Cell Non-Hodgkin Lymphoma
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NASA Astrophysics Data System (ADS)
Morozov, V. N.
2018-01-01
The problem of the penetration of nonstationary ionospheric electric fields into the lower atmospheric layers is considered based on the model of the global electric circuit in the Earth's atmosphere. For the equation of the electric field potential, a solution that takes into account exponential variation in the electrical conductivity with height has been obtained. Analysis of the solution made it possible to reveal three cases of the dependence of the solution on height. The first case (the case of high frequencies) corresponds to the Coulomb approximation, when the electrical conductivity of the atmosphere can be neglected. In the case of low frequencies (when the frequency of changes in the ionosphere potential is less than the quantity reciprocal to the time of electric relaxation of the atmosphere), a quasi-stationary regime, in which the variation in the electric potential of the atmosphere is determined by the electric conduction currents, occurs. In the third case, due to the increase in the electrical conductivity of the atmosphere, two spherical regions appear: with the Coulomb approximation in the lower region and conduction currents in the upper one. For these three cases, formulas for estimating the electric field strength near the Earth's surface have been obtained.
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Reactive conductors for increased efficiency of exploding foil initiators and other detonators
Morris, Christopher J.; Wilkins, Paul; May, Chadd; Zakar, Eugene
2015-05-05
Provided among other things are reactive energetic material systems used for conductors in detonators for increased efficiencies. According to an embodiment, a detonator may include: a conductor including at least two constituents including (i) an electrically conductive constituent, and (ii) an electrically non-conductive constituent, that when subjected to sufficient electrical energy, result in an exothermic reaction; and a flyer plate having a non-conductive surface in contact with said conductor. When the sufficient electrical energy is supplied to said conductor, rapid heating and vaporization of at least a portion of the conductor occurs so as to explosively drive at least a portion of the flyer plate away from said conductor. In an embodiment, a multilayer conductor may be formed of alternating layers of at least one electrically conductive layer, and at least one electrically non-conductive layer, that when subjected to sufficient electrical energy, result in an exothermic reaction.
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Modification of surface properties of copper-refractory metal alloys
Verhoeven, John D.; Gibson, Edwin D.
1993-10-12
The surface properties of copper-refractory metal (CU-RF) alloy bodies are modified by heat treatments which cause the refractory metal to form a coating on the exterior surfaces of the alloy body. The alloys have a copper matrix with particles or dendrites of the refractory metal dispersed therein, which may be niobium, vanadium, tantalum, chromium, molybdenum, or tungsten. The surface properties of the bodies are changed from those of copper to that of the refractory metal.
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Broccoli, Alessandro; Casadei, Beatrice; Morigi, Alice; Sottotetti, Federico; Gotti, Manuel; Spina, Michele; Volpetti, Stefano; Ferrero, Simone; Spina, Francesco; Pisani, Francesco; Merli, Michele; Visco, Carlo; Paolini, Rossella; Zilioli, Vittorio Ruggero; Baldini, Luca; Di Renzo, Nicola; Tosi, Patrizia; Cascavilla, Nicola; Molica, Stefano; Ilariucci, Fiorella; Rigolin, Gian Matteo; D'Alò, Francesco; Vanazzi, Anna; Santambrogio, Elisa; Marasca, Roberto; Mastrullo, Lucia; Castellino, Claudia; Desabbata, Giovanni; Scortechini, Ilaria; Trentin, Livio; Morello, Lucia; Argnani, Lisa; Zinzani, Pier Luigi
2018-05-04
Although sometimes presenting as an indolent lymphoma, mantle cell lymphoma (MCL) is an aggressive disease, hardly curable with standard chemo-immunotherapy. Current approaches have greatly improved patients' outcomes, nevertheless the disease is still characterized by high relapse rates. Before approval by EMA, Italian patients with relapsed/refractory MCL were granted ibrutinib early access through a Named Patient Program (NPP). An observational, retrospective, multicenter study was conducted. Seventy-seven heavily pretreated patients were enrolled. At the end of therapy there were 14 complete responses and 14 partial responses, leading to an overall response rate of 36.4%. At 40 months overall survival was 37.8% and progression free survival was 30%; disease free survival was 78.6% at 4 years: 11/14 patients are in continuous complete response with a median of 36 months of follow up. Hematological toxicities were manageable, and main extra-hematological toxicities were diarrhea (9.4%) and lung infections (9.0%). Overall, 4 (5.2%) atrial fibrillations and 3 (3.9%) hemorrhagic syndromes occurred. In conclusions, thrombocytopenia, diarrhea and lung infections are the relevant adverse events to be clinically focused on; regarding effectiveness, ibrutinib is confirmed to be a valid option for refractory/relapsed MCL also in a clinical setting mimicking the real world.
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Initial Clinical Experience with Ahmed Valve Implantation in Refractory Pediatric Glaucoma
Novak-Lauš, Katia; Škunca Herman, Jelena; Šimić Prskalo, Marija; Jurišić, Darija; Mandić, Zdravko
2016-12-01
The purpose is to report on the safety and efficacy of Ahmed Glaucoma Valve (AGV, New World Medical, Inc., Rancho Cucamonga, CA, USA) implantation for the management of refractory pediatric glaucoma observed during one-year follow up period. A retrospective chart review was conducted on 10 eyes, all younger than 11 years, with pediatric glaucoma that underwent AGV implantation for medicamentously uncontrolled intraocular pressure (IOP) between 2010 and 2014. Outcome measures were control of IOP below 23 mm Hg (with or without antiglaucoma medications) and changes in visual acuity. Complications were recorded. After AGV implantation, IOP values ranged from 18 mm Hg to 23 mm Hg (except for one eye with postoperative hypotonia due to suprachoroid hemorrhage, where the postoperative IOP value was 4 mm Hg). The number of antiglaucoma medications was reduced, i.e. four patients had two medications, one patient had one medication, and the others did not need antiglaucoma medication on the last follow-up visit. One eye had suprachoroid hemorrhage, one eye had long-term persistent uveitic membrane, and two eyes had tube-cornea touch. In conclusion, AGV implantation appears to be a viable option for the management of refractory pediatric glaucoma and shows success in IOP control. However, there was a relatively high complication rate limiting the overall success rate.
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Neuroimaging evaluation in refractory epilepsy
Granados, Ana M; Orejuela, Juan F
2015-01-01
Purpose To describe the application of neuroimaging analysis, compared to neuropsychological tests and video-electroencephalogram, for the evaluation of refractory epilepsy in a reference centre in Cali, Colombia. Methods Between March 2013 and November 2014, 29 patients, 19 men and 10 women, aged 9–65 years and with refractory epilepsy, were assessed by structural and functional magnetic resonance imaging while performing tasks related to language, verbal and non-verbal memory. Also, volumetric evaluation was performed. A 1.5 Tesla magnetic resonance imaging scanner was used in all cases. Results Neuroimaging evaluation identified 13 patients with mesial temporal sclerosis. The remaining patients were classified as: 10 patients with neoplastic masses, two patients with cortical atrophy, two patients with scarring lesions and two patients with non-structural aetiology. Among patients with mesial temporal sclerosis, comparison between techniques for lateralising the epileptogenic foci was made; the κ index between functional magnetic resonance imaging and hippocampi volumetry was κ = 1.00, agreement between neuroimaging and video-electroencephalogram was good (κ = 0.78) and comparison with a neuropsychological test was mild (κ = 0.24). Conclusions Neuroimaging studies allow the assessment of functional and structural damage related to epileptogenic lesions and foci, and are helpful to select surgical treatment, conduct intraoperative neuronavigation techniques, predict surgical deficits and evaluate patient recovery. PMID:26427897
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Vogl, Dan T; Stadtmauer, Edward A; Tan, Kay-See; Heitjan, Daniel F; Davis, Lisa E; Pontiggia, Laura; Rangwala, Reshma; Piao, Shengfu; Chang, Yunyoung C; Scott, Emma C; Paul, Thomas M; Nichols, Charles W; Porter, David L; Kaplan, Janeen; Mallon, Gayle; Bradner, James E; Amaravadi, Ravi K
2014-08-01
The efficacy of proteasome inhibition for myeloma is limited by therapeutic resistance, which may be mediated by activation of the autophagy pathway as an alternative mechanism of protein degradation. Preclinical studies demonstrate that autophagy inhibition with hydroxychloroquine augments the antimyeloma efficacy of the proteasome inhibitor bortezomib. We conducted a phase I trial combining bortezomib and hydroxychloroquine for relapsed or refractory myeloma. We enrolled 25 patients, including 11 (44%) refractory to prior bortezomib. No protocol-defined dose-limiting toxicities occurred, and we identified a recommended phase 2 dose of hydroxychloroquine 600 mg twice daily with standard doses of bortezomib, at which we observed dose-related gastrointestinal toxicity and cytopenias. Of 22 patients evaluable for response, 3 (14%) had very good partial responses, 3 (14%) had minor responses, and 10 (45%) had a period of stable disease. Electron micrographs of bone marrow plasma cells collected at baseline, after a hydroxychloroquine run-in, and after combined therapy showed therapy-associated increases in autophagic vacuoles, consistent with the combined effects of increased trafficking of misfolded proteins to autophagic vacuoles and inhibition of their degradative capacity. Combined targeting of proteasomal and autophagic protein degradation using bortezomib and hydroxychloroquine is therefore feasible and a potentially useful strategy for improving outcomes in myeloma therapy.
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Reaction Behaviors of Al-Killed Medium-Manganese Steel with Different Refractories
NASA Astrophysics Data System (ADS)
Kong, Lingzhong; Deng, Zhiyin; Zhu, Miaoyong
2018-03-01
In order to understand the reaction mechanism between medium-manganese steel and different refractories, some laboratory experiments were carried out at 1873 K (1600 °C). Three types of refractory plates (Al2O3, MgO, and MgO·Al2O3) were used. The results show that Mn in liquid medium-manganese steel does not react easily with the Al2O3 refractory, but can react with the MgO refractory to generate a (Mn, Mg)O layer at the boundary between the refractory plate and liquid steel. After the formation of (Mn, Mg)O, a layer of (Mn, Mg)O·Al2O3 spinel is also formed at the edge of the MgO refractory. Similar to the MgO refractory, the dissolved Mn can react with the MgO·Al2O3 refractory as well, and a layer of (Mn, Mg)O·Al2O3 was also detected after reaction. It was found that the formation of (Mn, Mg)O·Al2O3 at the edge of the refractory is a source of (Mn, Mg)O·Al2O3 inclusions in liquid steel. The flush-off of the (Mn, Mg)O·Al2O3 layer would result in the formation of (Mn, Mg)O·Al2O3 inclusions.
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Characterization of refractory brick based on local raw material from Lampung Province - Indonesia
NASA Astrophysics Data System (ADS)
Amin, Muhammad; Suryana, Yayat I.; Isnugroho, Kusno; Aji, Bramantyo B.; Birawidha, David C.; Hendronursito, Yusup
2018-04-01
Refractories are non-metallic inorganic materials that are difficult to melt at high temperatures and used in high-temperature casting industries. Refractories are classified into their constituent mineral feed stocks, refractories having typical plot properties commonly called fire bricks. In the manufacture of refractory bricks that exist in the market during the use of mangrove materials derived from abroad that is from China. In this research the refractory brick materials used are quartz sand, feldspart, kaolin, bentonite, and ball clay. All materials come from local Lampung Province - Indonesia. The experiment, there are 7 kinds of experimental composition, made of plot shape with size 230 mm, 65 mm in thickness, 114 mm height mould using manual press machine with 10 tons power and burning at 1400°C for 5 hours. Refractory brick product is done by physical test in the form of porosity, specific gravity, compressive strength and XRF and SEM characteristics. The result of XRF characteristic of refractory brick composition of 1 to 5 compared to the refractory brick type SK 34 in the market and the result of composition 1 is a composition close to refractory brick composition type SK 34 namely SiO2 is 54.21 %, Al2O3 is 25.38 % and test Physical of Bulk density is 2.25 g/cm3, porosity is 18.98 % and compressive strength is 325 kg/cm2.
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Lin, Lung-Chang; Ouyang, Chen-Sen; Chiang, Ching-Tai; Yang, Rei-Cheng; Wu, Rong-Ching; Wu, Hui-Chuan
2014-11-01
Refractory epilepsy often has deleterious effects on an individual's health and quality of life. Early identification of patients whose seizures are refractory to antiepileptic drugs is important in considering the use of alternative treatments. Although idiopathic epilepsy is regarded as having a significantly lower risk factor of developing refractory epilepsy, still a subset of patients with idiopathic epilepsy might be refractory to medical treatment. In this study, we developed an effective method to predict the refractoriness of idiopathic epilepsy. Sixteen EEG segments from 12 well-controlled patients and 14 EEG segments from 11 refractory patients were analyzed at the time of first EEG recordings before antiepileptic drug treatment. Ten crucial EEG feature descriptors were selected for classification. Three of 10 were related to decorrelation time, and four of 10 were related to relative power of delta/gamma. There were significantly higher values in these seven feature descriptors in the well-controlled group as compared to the refractory group. On the contrary, the remaining three feature descriptors related to spectral edge frequency, kurtosis, and energy of wavelet coefficients demonstrated significantly lower values in the well-controlled group as compared to the refractory group. The analyses yielded a weighted precision rate of 94.2%, and a 93.3% recall rate. Therefore, the developed method is a useful tool in identifying the possibility of developing refractory epilepsy in patients with idiopathic epilepsy.
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Refractory Wear Mechanisms in the Nonferrous Metal Industry: Testing and Modeling Results
NASA Astrophysics Data System (ADS)
Gregurek, D.; Ressler, A.; Reiter, V.; Franzkowiak, A.; Spanring, A.; Prietl, T.
2013-11-01
Nonferrous pyrometallurgical processes today operate at a high intensity requiring the best standards for the furnace refractory systems. From one plant to another, there is a range of process conditions such as temperature, slag chemistry, and feed types, and each of these parameters can influence refractory life. It is generally understood that process changes at plants can impact refractory life. The ability to test and understand refractory responses to a wide range of furnace operating conditions is therefore important. The RHI Technology Centre in Leoben, Austria is well equipped with laboratory and pilot plant facilities to evaluate refractory suitability over the range of conditions encountered in modern nonferrous pyrometallurgical systems. This article describes refractory testing at the RHI Technology Centre of the impact of two metallurgical slags on a number of different RHI test bricks. The slags were a fayalite slag and a calcium ferrite slag supplied by two smelter plants. High-temperature corrosion tests were carried out in a 250-mm-diameter induction furnace and a 165-mm-diameter short rotary kiln; each unit was lined with a number of refractory bricks and tested against attack by the particular slag. After testing, the refractory bricks were subjected to several laboratory tests to determine the extent of corrosion. Optimal refractory choices for the customers' plants were developed based on the test results.
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Reaction Behaviors of Al-Killed Medium-Manganese Steel with Different Refractories
NASA Astrophysics Data System (ADS)
Kong, Lingzhong; Deng, Zhiyin; Zhu, Miaoyong
2018-06-01
In order to understand the reaction mechanism between medium-manganese steel and different refractories, some laboratory experiments were carried out at 1873 K (1600 °C). Three types of refractory plates (Al2O3, MgO, and MgO·Al2O3) were used. The results show that Mn in liquid medium-manganese steel does not react easily with the Al2O3 refractory, but can react with the MgO refractory to generate a (Mn, Mg)O layer at the boundary between the refractory plate and liquid steel. After the formation of (Mn, Mg)O, a layer of (Mn, Mg)O·Al2O3 spinel is also formed at the edge of the MgO refractory. Similar to the MgO refractory, the dissolved Mn can react with the MgO·Al2O3 refractory as well, and a layer of (Mn, Mg)O·Al2O3 was also detected after reaction. It was found that the formation of (Mn, Mg)O·Al2O3 at the edge of the refractory is a source of (Mn, Mg)O·Al2O3 inclusions in liquid steel. The flush-off of the (Mn, Mg)O·Al2O3 layer would result in the formation of (Mn, Mg)O·Al2O3 inclusions.
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Lebedev, Vyacheslav; Bartlett, Joshua H.; Malyzhenkov, Alexander; ...
2017-12-06
Here, we present a novel compact design for a multichannel atomic oven which generates collimated beams of refractory atoms for fieldable laser spectroscopy. Using this resistively heated crucible, we demonstrate spectroscopy of an erbium sample at 1300 °C with improved isotopic resolution with respect to a single-channel design. In addition, our oven has a high thermal efficiency. By minimizing the surface area of the crucible, we achieve 2000 °C at 140 W of applied electrical power. As a result, the design does not require any active cooling and is compact enough to allow for its incorporation into fieldable instruments.
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Monolithic integrated high-T.sub.c superconductor-semiconductor structure
NASA Technical Reports Server (NTRS)
Barfknecht, Andrew T. (Inventor); Garcia, Graham A. (Inventor); Russell, Stephen D. (Inventor); Burns, Michael J. (Inventor); de la Houssaye, Paul R. (Inventor); Clayton, Stanley R. (Inventor)
2000-01-01
A method for the fabrication of active semiconductor and high-temperature superconducting device of the same substrate to form a monolithically integrated semiconductor-superconductor (MISS) structure is disclosed. A common insulating substrate, preferably sapphire or yttria-stabilized zirconia, is used for deposition of semiconductor and high-temperature superconductor substructures. Both substructures are capable of operation at a common temperature of at least 77 K. The separate semiconductor and superconductive regions may be electrically interconnected by normal metals, refractory metal silicides, or superconductors. Circuits and devices formed in the resulting MISS structures display operating characteristics which are equivalent to those of circuits and devices prepared on separate substrates.
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Hauptmann, C; Roulet, J-C; Niederhauser, J J; Döll, W; Kirlangic, M E; Lysyansky, B; Krachkovskyi, V; Bhatti, M A; Barnikol, U B; Sasse, L; Bührle, C P; Speckmann, E-J; Götz, M; Sturm, V; Freund, H-J; Schnell, U; Tass, P A
2009-12-01
In the past decade deep brain stimulation (DBS)-the application of electrical stimulation to specific target structures via implanted depth electrodes-has become the standard treatment for medically refractory Parkinson's disease and essential tremor. These diseases are characterized by pathological synchronized neuronal activity in particular brain areas. We present an external trial DBS device capable of administering effectively desynchronizing stimulation techniques developed with methods from nonlinear dynamics and statistical physics according to a model-based approach. These techniques exploit either stochastic phase resetting principles or complex delayed-feedback mechanisms. We explain how these methods are implemented into a safe and user-friendly device.
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Better Ohmic Contacts For InP Semiconductor Devices
NASA Technical Reports Server (NTRS)
Weizer, Victor G.; Fatemi, Navid S.
1995-01-01
Four design modifications enable fabrication of improved ohmic contacts on InP-based semiconductor devices. First modification consists of insertion of layer of gold phosphide between n-doped InP and metal or other overlayer of contact material. Second, includes first modification plus use of particular metal overlayer to achieve very low contact resistivities. Third, also involves deposition of Au(2)P(3) interlayer; in addition, refractory metal (W or Ta) deposited to form contact overlayer. In fourth, contact layer of Auln alloy deposited directly on InP. Improved contacts exhibit low electrical resistances and fabricated without exposing devices to destructive predeposition or postdeposition treatments.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Lebedev, Vyacheslav; Bartlett, Joshua H.; Malyzhenkov, Alexander
Here, we present a novel compact design for a multichannel atomic oven which generates collimated beams of refractory atoms for fieldable laser spectroscopy. Using this resistively heated crucible, we demonstrate spectroscopy of an erbium sample at 1300 °C with improved isotopic resolution with respect to a single-channel design. In addition, our oven has a high thermal efficiency. By minimizing the surface area of the crucible, we achieve 2000 °C at 140 W of applied electrical power. As a result, the design does not require any active cooling and is compact enough to allow for its incorporation into fieldable instruments.
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NASA Technical Reports Server (NTRS)
Thieme, Lanny G.; Schreiber, Jeffrey G.
2005-01-01
A high-efficiency, 110-W(sub e) (watts electric) Stirling Radioisotope Generator (SRG110) for possible use on future NASA Space Science missions is being developed by the Department of Energy, Lockheed Martin, Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). Potential mission use includes providing spacecraft onboard electric power for deep space missions and power for unmanned Mars rovers. GRC is conducting an in-house supporting technology project to assist in SRG110 development. One-, three-, and six-month heater head structural benchmark tests have been completed in support of a heater head life assessment. Testing is underway to evaluate the key epoxy bond of the permanent magnets to the linear alternator stator lamination stack. GRC has completed over 10,000 hours of extended duration testing of the Stirling convertors for the SRG110, and a three-year test of two Stirling convertors in a thermal vacuum environment will be starting shortly. GRC is also developing advanced technology for Stirling convertors, aimed at substantially improving the specific power and efficiency of the convertor and the overall generator. Sunpower, Inc. has begun the development of a lightweight Stirling convertor, under a NASA Research Announcement (NRA) award, that has the potential to double the system specific power to about 8 W(sub e) per kilogram. GRC has performed random vibration testing of a lowerpower version of this convertor to evaluate robustness for surviving launch vibrations. STC has also completed the initial design of a lightweight convertor. Status of the development of a multi-dimensional computational fluid dynamics code and high-temperature materials work on advanced superalloys, refractory metal alloys, and ceramics are also discussed.
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NASA Technical Reports Server (NTRS)
Thieme, Lanny G.; Schreiber, Jeffrey G.
2005-01-01
A high-efficiency, 110-We (watts electric) Stirling Radioisotope Generator (SRG110) for possible use on future NASA Space Science missions is being developed by the Department of Energy, Lockheed Martin, Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). Potential mission use includes providing spacecraft onboard electric power for deep space missions and power for unmanned Mars rovers. GRC is conducting an in-house supporting technology project to assist in SRG110 development. One-, three-, and six-month heater head structural benchmark tests have been completed in support of a heater head life assessment. Testing is underway to evaluate the key epoxy bond of the permanent magnets to the linear alternator stator lamination stack. GRC has completed over 10,000 hours of extended duration testing of the Stirling convertors for the SRG110, and a three-year test of two Stirling convertors in a thermal vacuum environment will be starting shortly. GRC is also developing advanced technology for Stirling convertors, aimed at substantially improving the specific power and efficiency of the convertor and the overall generator. Sunpower, Inc. has begun the development of a lightweight Stirling convertor, under a NASA Research Announcement (NRA) award, that has the potential to double the system specific power to about 8 We/kg. GRC has performed random vibration testing of a lower-power version of this convertor to evaluate robustness for surviving launch vibrations. STC has also completed the initial design of a lightweight convertor. Status of the development of a multi-dimensional computational fluid dynamics code and high-temperature materials work on advanced superalloys, refractory metal alloys, and ceramics are also discussed.
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Machining of Molybdenum by EDM-EP and EDC Processes
NASA Astrophysics Data System (ADS)
Wu, K. L.; Chen, H. J.; Lee, H. M.; Lo, J. S.
2017-12-01
Molybdenum metal (Mo) can be machined with conventional tools and equipment, however, its refractory propertytends to chip when being machined. In this study, the nonconventional processes of electrical discharge machining (EDM) and electro-polishing (EP) have been conducted to investigate the machining of Mo metal and fabrication of Mo grid. Satisfactory surface quality was obtained using appropriate EDM parameters of Ip ≦ 3A and Ton < 80μs at a constant pulse interval of 100μs. The finished Mometal has accomplished by selecting appropriate EP parameters such as electrolyte flow rate of 0.42m/s under EP voltage of 50V and flush time of 20 sec to remove the recast layer and craters on the surface of Mo metal. The surface roughness of machined Mo metal can be improved from Ra of 0.93μm (Rmax = 8.51μm) to 0.23μm (Rmax = 1.48μm). Machined Mo metal surface, when used as grid component in electron gun, needs to be modified by coating materials with high work function, such as silicon carbide (SiC). The main purpose of this study is to explore the electrical discharge coating (EDC) process for coating the SiC layer on EDMed Mo metal. Experimental results proved that the appropriate parameters of Ip = 5A and Ton = 50μs at Toff = 10μs can obtain the deposit with about 60μm thickness. The major phase of deposit on machined Mo surface was SiC ceramic, while the minor phases included MoSi2 and/or SiO2 with the presence of free Si due to improper discharging parameters and the use of silicone oil as the dielectric fluid.
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Igarashi, Tazuru; Niwano, Shinichi; Niwano, Hiroe; Yoshizawa, Tomoharu; Nakamura, Hironori; Fukaya, Hidehira; Fujiishi, Tamami; Ishizue, Naruya; Satoh, Akira; Kishihara, Jun; Murakami, Masami; Ako, Junya
2018-05-02
Dipeptidyl peptidase 4 (DPP-4) inhibitors have recently been reported to exhibit additional cardioprotective effects; however, their effect in atrial remodeling, such as in atrial fibrillation (AF), remains unclear. In this study, the effect of linagliptin on atrial electrical and structural remodeling was evaluated in a canine AF model. Sixteen beagle dogs with 3-week atrial rapid stimulation were divided into the linagliptin group (9 mg/kg/day, n = 8) and pacing control group (n = 8). Three additional dogs without rapid pacing were assigned into non-pacing group, which was used as sham in this study. In the dogs with rapid pacing, the atrial effective refractory period (AERP), conduction velocity (CV), and AF inducibility were evaluated and blood was sampled every week. After the entire protocol, atrial tissue was sampled for histological examinations using HE, Azan, and dihydroethidium (DHE) staining to evaluate any tissue damage or oxidative stress. The pacing control group exhibited a gradual AERP shortening and CV decrease along the time course as previously reported. In the linagliptin group, the AERP shortening was not affected, but the CV decrease was suppressed in comparison to the control group (p < 0.05). The AF inducibility was increased in the control group and suppressed in the linagliptin group (p < 0.05). The control group exhibited tissue fibrosis, the degree of which was suppressed in the linagliptin group. DHE staining exhibited suppression of the reactive oxygen species expression in the linagliptin group in comparison to the pacing control group. Linagliptin, a DPP-4-inhibitor, suppressed the AF inducibility, CV decrease, and overexpression of oxidative stress in the canine AF model. Such suppressive effects of linagliptin on AF in the canine model may possibly be related to the anti-oxidative effect.
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Electrochemical Device Comprising an Electrically-Conductive, Selectively-Permeable Membrane
NASA Technical Reports Server (NTRS)
Laicer, Castro S. T. (Inventor); Mittelsteadt, Cortney K. (Inventor); Harrison, Katherine E. (Inventor); McPheeters, Bryn M. (Inventor)
2017-01-01
An electrochemical device, such as a fuel cell or an electrolyzer. In one embodiment, the electrochemical device includes a membrane electrode assembly (MEA), an anodic gas diffusion medium in contact with the anode of the MEA, a cathodic gas diffusion medium in contact with the cathode, a first bipolar plate in contact with the anodic gas diffusion medium, and a second bipolar plate in contact with the cathodic gas diffusion medium. Each of the bipolar plates includes an electrically-conductive, non-porous, liquid-permeable, substantially gas-impermeable membrane in contact with its respective gas diffusion medium, the membrane including a solid polymer electrolyte and a non-particulate, electrically-conductive material, such as carbon nanotubes, carbon nanofibers, and/or metal nanowires. In addition, each bipolar plate also includes an electrically-conductive fluid chamber in contact with the electrically-conductive, selectively-permeable membrane and further includes a non-porous and electrically-conductive plate in contact with the fluid chamber.
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NASA Astrophysics Data System (ADS)
E, Lotfi; H, Rezania; B, Arghavaninia; M, Yarmohammadi
2016-07-01
We address the electrical conductivity of bilayer graphene as a function of temperature, impurity concentration, and scattering strength in the presence of a finite bias voltage at finite doping, beginning with a description of the tight-binding model using the linear response theory and Green’s function approach. Our results show a linear behavior at high doping for the case of high bias voltage. The effects of electron doping on the electrical conductivity have been studied via changing the electronic chemical potential. We also discuss and analyze how the bias voltage affects the temperature behavior of the electrical conductivity. Finally, we study the behavior of the electrical conductivity as a function of the impurity concentration and scattering strength for different bias voltages and chemical potentials respectively. The electrical conductivity is found to be monotonically decreasing with impurity scattering strength due to the increased scattering among electrons at higher impurity scattering strength.
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Downhole data transmission system
Hall, David R.; Hall, Jr., H. Tracy; Pixton, David S; Dahlgren, Scott; Fox, Joe
2006-06-20
A system for transmitting data through a string of downhole components. In one aspect, the system includes first and second magnetically conductive, electrically insulating elements at both ends of the component. Each element includes a first U-shaped trough with a bottom, first and second sides and an opening between the two sides. Electrically conducting coils are located in each trough. An electrical conductor connects the coils in each component. In operation, a varying current applied to a first coil in one component generates a varying magnetic field in the first magnetically conductive, electrically insulating element, which varying magnetic field is conducted to and thereby produces a varying magnetic field in the second magnetically conductive, electrically insulating element of a connected component, which magnetic field thereby generates a varying electrical current in the second coil in the connected component.
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Downhole Data Transmission System
Hall, David R.; Hall, Jr., H. Tracy; Pixton, David; Dahlgren, Scott; Fox, Joe
2003-12-30
A system for transmitting data through a string of downhole components. In one aspect, the system includes first and second magnetically conductive, electrically insulating elements at both ends of the component. Each element includes a first U-shaped trough with a bottom, first and second sides and an opening between the two sides. Electrically conducting coils are located in each trough. An electrical conductor connects the coils in each component. In operation, a varying current applied to a first coil in one component generates a varying magnetic field in the first magnetically conductive, electrically insulating element, which varying magnetic field is conducted to and thereby produces a varying magnetic field in the second magnetically conductive, electrically insulating element of a connected component, which magnetic field thereby generates a varying electrical current in the second coil in the connected component.
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NASA Astrophysics Data System (ADS)
Jesús Moral García, Francisco; Rebollo Castillo, Francisco Javier; Monteiro Santos, Fernando
2016-04-01
Maps of apparent electrical conductivity of the soil are commonly used in precision agriculture to indirectly characterize some important properties like salinity, water, and clay content. Traditionally, these studies are made through an empirical relationship between apparent electrical conductivity and properties measured in soil samples collected at a few locations in the experimental area and at a few selected depths. Recently, some authors have used not the apparent conductivity values but the soil bulk conductivity (in 2D or 3D) calculated from measured apparent electrical conductivity through the application of an inversion method. All the published works used data collected with electromagnetic (EM) instruments. We present a new software to invert the apparent electrical conductivity data collected with VERIS 3100 and 3150 (or the more recent version with three pairs of electrodes) using the 1D spatially constrained inversion method (1D SCI). The software allows the calculation of the distribution of the bulk electrical conductivity in the survey area till a depth of 1 m. The algorithm is applied to experimental data and correlations with clay and water content have been established using soil samples collected at some boreholes. Keywords: Digital soil mapping; inversion modelling; VERIS; soil apparent electrical conductivity.
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Cheng, Yehong; Zhou, Shanbao; Hu, Ping; Zhao, Guangdong; Li, Yongxia; Zhang, Xinghong; Han, Wenbo
2017-05-03
Graphene aerogels with high surface areas, ultra-low densities and thermal conductivities have been prepared to exploit their wide applications from pollution adsorption to energy storage, supercapacitor, and thermal insulation. However, the low mechanical properties, poor thermal stability and electric conductivity restrict these aerogels' applications. In this paper, we prepared mechanically strong graphene aerogels with large BET surface areas, low thermal conductivities, high thermal stability and electric conductivities via hydrothermal reduction and supercritical ethanol drying. Annealing at 1500 °C resulted in slightly increased thermal conductivity and further improvement in mechanical properties, oxidation temperature and electric conductivity of the graphene aerogel. The large BET surface areas, together with strong mechanical properties, low thermal conductivities, high thermal stability and electrical conductivities made these graphene aerogels feasible candidates for use in a number of fields covering from batteries to sensors, electrodes, lightweight conductor and insulation materials.
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Differential and directional effects of perfusion on electrical and thermal conductivities in liver.
Podhajsky, Ronald J; Yi, Ming; Mahajan, Roop L
2009-01-01
Two different measurement probes--an electrical probe and a thermal conductivity probe--were designed, fabricated, calibrated, and used in experimental studies on a pig liver model that was designed to control perfusion rates. These probes were fabricated by photolithography and mounted in 1.5-mm diameter catheters. We measured the local impedance and thermal conductivity, respectively, of the artificially perfused liver at different flow rates and, by rotating the probes, in different directions. The results show that both the local electrical conductivity and the thermal conductivity varied location to location, that thermal conductivity increased with decreased distance to large blood vessels, and that significant directional differences exist in both electrical and thermal conductivities. Measurements at different perfusion rates demonstrated that both the local electrical and local thermal conductivities increased linearly with the square root of perfusion rate. These correlations may be of great value to many energy-based biomedical applications.
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2018-03-05
Relapsed Acute Lymphoblastic Leukemia (ALL); Refractory Acute Lymphoblastic Leukemia (ALL); Relapsed Acute Myelogenous Leukemia (AML); Refractory Acute Myelogenous Leukemia (AML); Relapsed Mixed Lineage Leukemia; Refractory Mixed Lineage Leukemia; Relapsed Biphenotypic Leukemia; Refractory Biphenotypic Leukemia; Chronic Myelogenous Leukemia (CML) in Blast Crisis
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2018-05-23
ALK Positive; BCL6 Positive; Recurrent Anaplastic Large Cell Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Mantle Cell Lymphoma; Refractory Anaplastic Large Cell Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Mantle Cell Lymphoma
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2018-02-28
Acute Leukemia of Ambiguous Lineage; Recurrent Adult Acute Lymphoblastic Leukemia; Recurrent Adult Acute Myeloid Leukemia; Recurrent Childhood Acute Lymphoblastic Leukemia; Recurrent Childhood Acute Myeloid Leukemia; Refractory Acute Myeloid Leukemia; Refractory Adult Acute Lymphoblastic Leukemia; Refractory Childhood Acute Lymphoblastic Leukemia
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2018-05-22
Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Hodgkin Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent T-Cell Non-Hodgkin Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Hodgkin Lymphoma; Refractory Mantle Cell Lymphoma; Refractory T-Cell Non-Hodgkin Lymphoma
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2017-12-04
Post-Transplant Lymphoproliferative Disorder; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Burkitt Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Burkitt Lymphoma; Refractory Diffuse Large B-Cell Lymphoma
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Capillary zone electrophoresis-mass spectrometer interface
D`Silva, A.
1996-08-06
A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conductors is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer. 1 fig.
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NASA Astrophysics Data System (ADS)
Benallou, Amina; Hadri, Baghdad; Martinez-Vega, Juan; El Islam Boukortt, Nour
2018-04-01
The effect of percolation threshold on the behaviour of electrical conductivity at high electric field of insulating polymers has been briefly investigated in literature. Sometimes the dead ends links are not taken into account in the study of the electric field effect on the electrical properties. In this work, we present a theoretical framework and Monte Carlo simulation of the behaviour of the electric conductivity at high electric field based on the percolation theory using the traps energies levels which are distributed according to distribution law (uniform, Gaussian, and power-law). When a solid insulating material is subjected to a high electric field, and during trapping mechanism the dead ends of traps affect with decreasing the electric conductivity according to the traps energies levels, the correlation length of the clusters, the length of the dead ends, and the concentration of the accessible positions for the electrons. A reasonably good agreement is obtained between simulation results and the theoretical framework.
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A percolation model for electrical conduction in wood with implications for wood-water relations
Samuel L. Zelinka; Samuel V. Glass; Donald S. Stone
2008-01-01
The first models used to describe electrical conduction in cellulosic materials involved conduction pathways through free water. These models were abandoned in the middle of the 20th century. This article re-evaluates the theory of conduction in wood by using a percolation model that describes electrical conduction in terms of overlapping paths of loosely bound or...
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DEEP DESULFURIZATION OF DIESEL FUELS BY A NOVEL INTEGRATED APPROACH
DOE Office of Scientific and Technical Information (OSTI.GOV)
Xiaoliang Ma; Uday Turaga; Shingo Watanabe
2004-05-01
The overall objective of this project is to explore a new desulfurization system concept, which consists of efficient separation of the refractory sulfur compounds from diesel fuel by selective adsorption, and effective hydrodesulfurization of the concentrated fraction of the refractory sulfur compounds in diesel fuels. Our approaches focused on (1) selecting and developing new adsorbents for selective adsorption of sulfur or sulfur compounds in commercial diesel fuel; (2) conducting the adsorption desulfurization of model fuels and real diesel fuels by the selective-adsorption-for-removing-sulfur (PSUSARS) process over various developed adsorbents, and examining the adsorptive desulfurization performance of various adsorbents; (3) developing andmore » evaluating the regeneration methods for various spent adsorbent; (4) developing new catalysts for hydrodesulfurization of the refractory sulfur existing in the commercial diesel fuel; (5) on the basis of the fundamental understanding of the adsorptive performance and regeneration natures of the adsorbents, further confirming and improving the conceptual design of the novel PSU-SARS process for deep desulfurization of diesel fuel Three types of adsorbents, the metal-chloride-based adsorbents, the activated nickel-based adsorbents and the metal-sulfide-based adsorbents, have been developed for selective adsorption desulfurization of liquid hydrocarbons. All of three types of the adsorbents exhibit the significant selectivity for sulfur compounds, including alkyl dibenzothiophenes (DBTs), in diesel fuel. Adsorption desulfurization of real diesel fuels (regular diesel fuel (DF), S: 325 ppmw; low sulfur diesel fuel (LSD-I), S: 47 ppmw) over the nickel-based adsorbents (A-2 and A-5) has been conducted at different conditions by using a flowing system. The adsorption capacity of DF over A-2 corresponding to an outlet sulfur level of 30 ppmw is 2.8 mg-S/g-A. The adsorption capacity of LSD-I over A-5 corresponding to the break-through point at 5.0 ppmw sulfur level is 0.35 mg-S/g-A. The spent A-5 can be regenerated by using H2 gas at a flowing rate of 40-50 ml/min, 500 C, and ambient pressure. Adsorption desulfurization of model diesel fuels over metal-sulfide-based adsorbents (A-6-1 and A-6-2) has been conducted at different temperatures to examine the capacity and selectivity of the adsorbents. A regeneration method for the spent metal-sulfide-based adsorbents has been developed. The spent A-6-1 can be easily regenerated by washing the spent adsorbent with a polar solvent followed by heating the adsorbent bed to remove the remainder solvent. Almost all adsorption capacity of the fresh A-6-1 can be recovered after the regeneration. On the other hand, a MCM-41-supported HDS catalyst was developed for deep desulfurization of the refractory sulfur compounds. The results show that the developed MCM-41-supported catalyst demonstrates consistently higher activity for the HDS of the refractory dibenzothiophenic sulfur compounds than the commercial catalyst. On the basis of the fundamental understanding of the adsorptive performance and regeneration natures of the adsorbents, the conceptual design of the novel PSU-SARS process for deep desulfurization of diesel fuel is confirmed and improved further.« less
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The reliability of thermocouples in microwave ceramics processing.
Aguilar, Juan; Valdez, Zarel; Ortiz, Ubaldo
2004-01-01
It is not rare to hear arguments against the use of thermocouples for taking temperatures in processes that are taking place under microwave fields. However, the simplicity of this device makes it attractive to consider its use. One question that arises when thermocouples are employed is whether the electric field perturbs the measurement, and if the thermocouple affects the processing. The process that was chosen for conducting this test was the synthesis of spinel (MgAl2O4) using microwaves as a power supply and hematite (Fe2O3) as an additive for both spinel formation promotion and susceptor. The alumina-based systems are very important to study because this is one of the most common ingredients in refractory materials. There are many discussions about the improvement of the process when microwaves are used, but a kinetic comparison cannot be performed if the temperature is unknown, and that is the reason for emphasizing the measurement techniques. The analysis of the obtained samples was carried out by X-ray diffraction of powders. The results of this work show that there is no difference between the products obtained when the thermocouple was inserted in the system, compared to processing without it; hence the thermocouple is appropriate for this application.
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Refractory thermowell for continuous high temperature measurement of molten metal
Thiesen, Todd J.
1992-01-01
An apparatus for the continuous high temperature measurement of materials in vessels lined with rammed or cast refractory materials. A refractory housing member is integral with the refractory lining of the vessel and contains a plurality of high temperature sensing means, such as thermocouples. A face of the housing is flush with the refractory lining and contacts the high temperature material contained in the vessel. Continuous temperature measurement is achieved by a means which is coupled to the thermocouples for indicating the temperature.
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Electrically conductive material
Singh, J.P.; Bosak, A.L.; McPheeters, C.C.; Dees, D.W.
1993-09-07
An electrically conductive material is described for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO[sub 2] as a matrix and 6-19 wt. % monoclinic ZrO[sub 2] formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO[sub 2] as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns. 8 figures.
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All diamond self-aligned thin film transistor
Gerbi, Jennifer [Champaign, IL
2008-07-01
A substantially all diamond transistor with an electrically insulating substrate, an electrically conductive diamond layer on the substrate, and a source and a drain contact on the electrically conductive diamond layer. An electrically insulating diamond layer is in contact with the electrically conductive diamond layer, and a gate contact is on the electrically insulating diamond layer. The diamond layers may be homoepitaxial, polycrystalline, nanocrystalline or ultrananocrystalline in various combinations.A method of making a substantially all diamond self-aligned gate transistor is disclosed in which seeding and patterning can be avoided or minimized, if desired.
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Perforation patterned electrical interconnects
Frey, Jonathan
2014-01-28
This disclosure describes systems and methods for increasing the usable surface area of electrical contacts within a device, such as a thin film solid state device, through the implementation of electrically conductive interconnects. Embodiments described herein include the use of a plurality of electrically conductive interconnects that penetrate through a top contact layer, through one or more multiple layers, and into a bottom contact layer. The plurality of conductive interconnects may form horizontal and vertical cross-sectional patterns. The use of lasers to form the plurality of electrically conductive interconnects from reflowed layer material further aids in the manufacturing process of a device.
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Capacitor discharge process for welding braided cable
Wilson, Rick D.
1995-01-01
A capacitor discharge process for welding a braided cable formed from a plurality of individual cable strands to a solid metallic electrically conductive member comprises the steps of: (a) preparing the electrically conductive member for welding by bevelling one of its end portions while leaving an ignition projection extending outwardly from the apex of the bevel; (b) clamping the electrically conductive member in a cathode fixture; (c) connecting the electrically conductive member clamped in the cathode fixture to a capacitor bank capable of being charged to a preselected voltage value; (d) preparing the braided cable for welding by wrapping one of its end portions with a metallic sheet to form a retaining ring operable to maintain the individual strands of the braided cable in fixed position within the retaining ring; (e) clamping the braided cable and the retaining ring as a unit in an anode fixture so that the wrapped end portion of the braided cable faces the ignition projection of the electrically conductive member; and (f) moving the cathode fixture towards the anode fixture until the ignition projection of the electrically conductive member contacts the end portion of the braided cable thereby allowing the capacitor bank to discharge through the electrically conductive member and through the braided cable and causing the electrically conductive member to be welded to the braided cable via capacitor discharge action.
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Simplified Calculation of the Electrical Conductivity of Composites with Carbon Nanotubes
NASA Astrophysics Data System (ADS)
Ivanov, S. G.; Aniskevich, A.; Kulakov, V.
2018-03-01
The electrical conductivity of two groups of polymer nanocomposites filled with the same NC7000 carbon nanotubes (CNTs) beyond the percolation threshold is described with the help of simple formulas. Different manufacturing process of the nanocomposites led to different CNT network structures, and, as a consequence, their electrical conductivity, at the same CNT volume, differed by two orders of magnitude. The relation between the electrical conductivity and the volume content of CNTs of the first group of composites (with a higher electrical conductivity) is described assuming that the CNT network structure is close to a statistically homogeneous one. The formula for this case, derived on the basis of a self-consistent model, includes only two parameters: the effective longitudinal electrical conductivity of CNT and the percolation threshold (the critical value of CNT volume content). These parameters were determined from two experimental points of electrical conductivity as a function of the volume fraction of CNTs. The second group of nanocomposites had a pronounced agglomerative structure, which was confirmed by microscopy data. To describe the low electrical conductivity of this group of nanocomposites, a formula based on known models of micromechanics is proposed. Two parameters of this formula were determined from experimental data of the first group, but the other two — of the second group of nanocomposites. A comparison of calculation and experimental relations confirmed the practical expediency of using the approach described.
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Gong, Jun; Wu, Daniel; Chuang, Jeremy; Tuli, Richard; Simard, John; Hendifar, Andrew
2017-11-01
This review highlights the evidence supporting symptom control and quality-of-life (QOL) measures as predictors of survival in treatment-refractory metastatic colorectal cancer (mCRC) and describes a composite symptom control and QOL end point recently reported in a Phase III trial that may serve as a more reasonable end point of efficacy in this population. A literature search was conducted using MEDLINE to identify clinical studies (including case series and observational, retrospective, and prospective studies) that reported the predictive value of QOL measures for survival in mCRC. The search was limited by the following key words: quality of life, survival, and colorectal cancer. We then performed a second search limited to studies of randomized and Phase III design in mCRC to identify studies that used QOL assessments as their primary end points. A manual search was also performed to include additional studies of potential relevance. There is increasing evidence to support that symptom control and QOL measures are predictors of survival in treatment-refractory mCRC and can serve as an alternative but equally as important end point to survival in this population. A recent large, randomized Phase III trial using a composite primary end point of lean body mass, pain, anorexia, and fatigue reported the feasibility in evaluating benefit in mCRC beyond conventional clinical trial end points. Future studies in treatment-refractory mCRC may be better served by evaluating improvement in symptom control and QOL, which may otherwise serve as the best predictor of survival in last-line treatment settings. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.
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The Ahmed Glaucoma Valve in Refractory Glaucoma: Experiences in Southwest Ethiopia.
Gessesse, Girum W
2015-07-01
The management of refractory glaucoma is a challenging task for any glaucoma surgeon. This study is aimed to evaluate the efficacy of Ahmed Glaucoma Valve implantation in refractory glaucomas in South-West Ethiopia. A retrospective review was conducted on the charts of consecutive patients treated with Ahmed glaucoma valve implantation at Jimma University Specialized Hospital between August 2012 and August 2014. Success was defined as Intraocular Pressure (IOP) less than 22 mm Hg and greater than 5mm Hg at 6 months, with at least 30% reduction from baseline, without medical therapy (complete success) or either with or without medication (qualified successes). A total of 12 eyes of 11 patients were included. The mean age of patients was 40.7 (SD= 19.0) years; 63.6% of them were males. The main types of glaucoma were pseudoexfoliative (3 eyes), uveitic (2 eyes), chronic angle closure (2 eyes) and Juvenile Open Angle (JOAG) (2 eyes). The mean IOP was reduced from preoperative level (32.75±7.14 mmHg) to (15.75 ±4.35 mmHg) at six postoperative months, (P<0.001); 66.7% eyes had complete successes while 83.3% had qualified success. Intra-operative complications were encountered in 2(16.7%) eyes, while 5/12 (41.7%) eyes had post-operative complications-hypotony (one with choroidal effusion) and progression of cataract in 2 eyes each. Hypertensive phase was diagnosed in 2(16.7%) eyes. The Ahmed glaucoma valve implant appears to be effective and relatively safe for treating complicated glaucomas with success rate comparable with those reported from other studies. Ahmed glaucoma valve, refractory glaucoma, complications, Ethiopia.
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[Long-term outcomes of Ahmed glaucoma valve implantation for treating refractory glaucoma].
Xu, Yumei; Hong, Tao; Li, Wanming
2015-02-10
To explore the efficacies and complications of Ahmed glaucoma valve implantation for treating refractory glaucoma. A retrospective study of case series was conducted for 24 patients (26 eyes) with refractory glaucoma from February 2001 to July 2008 at our hospital. Ahmed glaucoma valve implantation was performed. Pre- and post-operative best spectacle-corrected visual acuity (BSCVA), intraocular pressure (IOP), number of medications and complications were recorded and analyzed. The follow-up period was 58-159 months. The post-operative values of IOP were 13.02+/-6.79, 11.43+/-5.24 and 18.56+/-6.43 mmHg at 1 day, 1 month and the last follow-up respectively. There were significant difference when compared with pre-operative IOP (37.59+/-10.76 mmHg, P < 0.01). And 65.38% of eyes maintained or gained ≥ 1 line of BSCVA. But there was no significant difference with pre-operative BSCVA (P = 0.110). Twenty eyes required anti-glaucoma drugs after glaucoma valve implantation and the average number of medication was 1.72+/-0.98. There was significant difference with the pre-operative medication number 2.7 ± 0.7 (P = 0.001). The surgical success rate was 73.1%. And the causes of failure were endophthalmitis, corneal endothelial decompensation, persistent conjunctival wound non-healing, glaucoma valve exposure and loss of light perception.Early postoperative complications were ocular hypotony, shallow anterior chamber, hyphema, transient high IOP and tube occlusion. And long-term complications included encapsulated cyst formation, tube exposure, corneal endothelial decompensation and endophthalmitis. Ahmed glaucoma valve implantation is efficacious for refractory glaucoma.However, clinicians should pay attention to the prevention and treatment of complications.
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Gong, Feilong; Li, Peng; Li, Bin; Zhang, Shizhen; Zhang, Xinjie; Yang, Sen; Liu, Hongbin; Wang, Wei
2018-02-01
OBJECTIVE Anterior capsulotomy (AC) is sometimes used as a last resort for treatment-refractory obsessive-compulsive disorder (OCD). Previous studies assessing neuropsychological outcomes in patients with OCD have identified several forms of cognitive dysfunction that are associated with the disease, but few have focused on changes in cognitive function in OCD patients who have undergone surgery. In the present study, the authors investigated the effects of AC on the cognitive function of patients with treatment-refractory OCD. METHODS The authors selected 14 patients with treatment-refractory OCD who had undergone bilateral AC between 2007 and 2013, 14 nonsurgically treated OCD patients, and 14 healthy control subjects for this study. The 3 groups were matched for sex, age, and education. Several neuropsychological tests, including Similarities and Block Design, which are subsets of the Wechsler Abbreviated Scale of Intelligence; Immediate and Delayed Logical Memory and Immediate and Delayed Visual Reproduction, which are subsets of the Wechsler Memory Scale-Revised; and Corrects, Categories, Perseverative Errors, Nonperseverative Errors, and Errors, subtests of the Wisconsin Card Sorting Test, were conducted in all 42 subjects at baseline and after AC, after nonsurgical treatment, or at 6-month intervals, as appropriate. The Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) was used to measure OCD symptoms in all 28 OCD patients. RESULTS The Y-BOCS scores decreased significantly in both OCD groups during the 12-month follow-up period. Surgical patients showed higher levels of improvement in verbal memory, visual memory, visuospatial skills, and executive function than the nonsurgically treated OCD patients. CONCLUSIONS The findings of this study suggest that AC not only reduces OCD symptoms but also attenuates moderate cognitive deficits.
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Izawa, Shinya; Funaki, Yasushi; Iida, Akihito; Tokudome, Kentaro; Tamura, Yasuhiro; Ogasawara, Naotaka; Sasaki, Makoto; Kasugai, Kunio
2014-01-01
The symptom improvement rate is low with proton pump inhibitors (PPIs) in nonerosive reflux disease (NERD). The underlying pathogenic mechanism is complex. Esophageal motility disorders (EMDs) are thought to be a factor, but their prevalence, type, symptoms and the role played by gastroesophageal reflux (GER) in symptom onset have not been fully investigated. To investigate the role of GER in symptom onset in PPI-refractory NERD patients with EMDs. This study comprised 76 patients with PPI-refractory NERD. Manometry was performed during PPI treatment and patients were divided into an EMD group and normal motility (non-EMD) group. Then, multichannel intraluminal impedance-pH monitoring was performed and medical interviews were conducted. Nineteen patients (25%) had an EMD. Data were compared between 17 patients, excluding 2 with achalasia and 57 non-EMD patients. No significant differences were observed between groups in 24-hour intraesophageal pH <4 holding time (HT), mean number of GER episodes or mean number of proximal reflux episodes. The reflux-related symptom index (≥50%) showed a relationship between reflux and symptoms in 70.5% of EMD patients and 75% of non-EMD patients. In the EMD group, the score for FSSG (Frequency Scale for the Symptoms of GERD) question (Q)10 was significantly correlated with the number of GER episodes (r = 0.58, p = 0.02) and the number of proximal reflux episodes (r = 0.63, p = 0.02). In addition, the score for Q9 tended to be correlated with the number of GER episodes (r = 0.44, p = 0.06). Our results suggest that some PPI-refractory NERD patients have EMDs, and that GER plays a role in symptom onset.
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Li, Ling; Xiao, Sa; Zhang, Lei; Li, Xin; Fu, Xiaorui; Wang, Xinhua; Wu, Jingjing; Sun, Zhenchang; Zhang, Xudong; Chang, Yu; Nan, Feifei; Yan, Jiaqin; Li, Zhaoming; Shi, Mengyuan; Young, Ken H; Zhang, Mingzhi
2018-03-23
Apatinib, a novel small molecule vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase inhibitor, have shown remarkable efficacy in many solid cancers. But evidence of antitumor activity in patients with lymphoma is still limited. We conducted an open-label, single-armed, exploratory study in relapse or refractory non-Hodgkin lymphoma patients for the efficacy and safety of apatinib. Patients with relapse or refractory non-Hodgkin patients meet the criteria were eligible for enrollment. Treatment comprised of oral apatinib 500 mg once daily with 21 days as a treatment cycle. The primary end point was response rate. Secondary end points included progression-free survival (PFS) and overall survival (OS). Between February 2016 and December 2016, 21 patients were enrolled. The ORR (CR plus PR) was 47.6% (10 of 21 patients) included 9.5% CRs and 38.1% PRs. 23.8% patients achieved stable disease made the DCR 71.4% (15/21). The median OS was 7.3 months (95% CI, 7.1 to 7.9) and the median PFS was 7.1 months (95% CI, 4.2 to 7.3). Most patients suffered from grade 1 to grade 2 treatment-related adverse events and the most common nonhematologic adverse events were proteinuria (47.6%), hypertension (42.9%) and hand-foot syndrome (33.3%), respectively. In our study, the results we presented showed apatinib might have a rapid, safe and high efficacy on relapsed or refractory non-Hodgkin lymphoma patients. Based on the data more clinic trials are expected to be taken to identification the efficacy of apatinib on lymphoma further.
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Plasma-Sprayed Refractory Oxide Coatings on Silicon-Base Ceramics
NASA Technical Reports Server (NTRS)
Tewari, Surendra
1997-01-01
Silicon-base ceramics are promising candidate materials for high temperature structural applications such as heat exchangers, gas turbines and advanced internal combustion engines. Composites based on these materials are leading candidates for combustor materials for HSCT gas turbine engines. These materials possess a combination of excellent physical and mechanical properties at high temperatures, for example, high strength, high toughness, high thermal shock resistance, high thermal conductivity, light weight and excellent oxidation resistance. However, environmental durability can be significantly reduced in certain conditions such as when molten salts, H2 or water vapor are present. The oxidation resistance of silicon-base materials is provided by SiO2 protective layer. Molten salt reacts with SiO2 and forms a mixture of SiO2 and liquid silicate at temperatures above 800C. Oxygen diffuses more easily through the chemically altered layer, resulting in a catastrophic degradation of the substrate. SiC and Si3N4 are not stable in pure H2 and decompose to silicon and gaseous species such as CH4, SiH, SiH4, N2, and NH3. Water vapor is known to slightly increase the oxidation rate of SiC and Si3N4. Refractory oxides such as alumina, yttria-stabilized zirconia, yttria and mullite (3Al2O3.2SiO2) possess excellent environmental durability in harsh conditions mentioned above. Therefore, refractory oxide coatings on silicon-base ceramics can substantially improve the environmental durability of these materials by acting as a chemical reaction barrier. These oxide coatings can also serve as a thermal barrier. The purpose of this research program has been to develop refractory oxide chemical/thermal barrier coatings on silicon-base ceramics to provide extended temperature range and lifetime to these materials in harsh environments.
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Isozaki, Hideko; Hotta, Katsuyuki; Ichihara, Eiki; Takigawa, Nagio; Ohashi, Kadoaki; Kubo, Toshio; Ninomiya, Takashi; Ninomiya, Kiichiro; Oda, Naohiro; Yoshioka, Hiroshige; Ichikawa, Hirohisa; Inoue, Masaaki; Takata, Ichiro; Shibayama, Takuo; Kuyama, Shoichi; Sugimoto, Keisuke; Harada, Daijiro; Harita, Shingo; Sendo, Toshiaki; Tanimoto, Mitsune; Kiura, Katsuyuki
2016-11-01
Based on our preclinical study results, which showed that the activation of the hepatocyte growth factor/MET pathway is a potential mechanism of acquired resistance to alectinib, we launched the ALRIGHT (OLCSG1405 [alectinib-refractory non-small-cell lung cancer patients harboring the EML4-ALK fusion gene]), a phase II trial of the anaplastic lymphoma kinase (ALK)/MET inhibitor crizotinib in patients with non-small-cell lung cancer refractory to alectinib and harboring the echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion gene. Patients with ALK-rearranged tumors who have developed disease progression during alectinib treatment will receive crizotinib monotherapy until disease progression or the occurrence of unacceptable toxicity. The primary endpoint is set as the objective response rate, assuming that a response in 50% of eligible patients will indicate potential usefulness and that 15% would be the lower limit of interest (1-sided α of 0.05, β of 0.20). The estimated accrual number of patients is 9. The secondary endpoints include progression-free survival, overall survival, adverse events, and patient-reported outcomes. We will also take tissue samples before crizotinib monotherapy to conduct an exploratory analysis of ALK and hepatocyte growth factor/MET expression levels and gene alterations (eg, mutations, amplifications, and translocations). We will obtain information regarding whether crizotinib, which targets not only ALK, but also MET, can truly produce efficacy with acceptable safety profiles in ALK + non-small-cell lung cancer even in the alectinib-refractory setting. Copyright © 2016 Elsevier Inc. All rights reserved.
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Epperla, Narendranath; Hamadani, Mehdi; Cashen, Amanda F; Ahn, Kwang W; Oak, Eunhye; Kanate, Abraham S; Calzada, Oscar; Cohen, Jonathon B; Farmer, Luke; Ghosh, Nilanjan; Tallarico, Michael; Nabhan, Chadi; Costa, Luciano J; Kenkre, Vaishalee P; Hari, Parameswaran N; Fenske, Timothy S
2017-12-01
Ibrutinib has demonstrated significant activity in relapsed/refractory mantle cell lymphoma (MCL) in clinical trials. However, the impact of hematopoietic cell transplantation on the outcomes of ibrutinib and the predictive factors for ibrutinib response has not been well studied. Hence, we conducted a multicenter retrospective study of MCL patients who received ibrutinib to (1) determine the overall response rate (ORR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS) of ibrutinib in routine clinical practice, (2) examine characteristics predictive of response to ibrutinib therapy, and (3) describe the outcomes of patients failing ibrutinib. Ninety-seven patients met the eligibility criteria. Overall response rate and median DOR to ibrutinib were 65% and 17 months, respectively. Only lack of primary refractory disease was predictive of ibrutinib response on multivariate analysis. Twenty-nine patients received postibrutinib therapies, with an ORR of 48% and a median DOR of 3 months. The median OS and PFS for the entire group (n = 97) was 22 and 15 months, respectively. On multivariate analysis, ibrutinib response, low MCL international prognostic index, and absence of primary refractory disease were predictors of better PFS, while ibrutinib response and Eastern Cooperative Oncology Group performance status ≤1 were predictors of better OS. The median OS postibrutinib failure was 2.5 months. Our results confirm the high ORR and DOR of ibrutinib in MCL and that prior hematopoietic cell transplantation does not negatively influence ibrutinib outcomes. Survival following ibrutinib failure is poor with no specific subsequent therapy showing superior activity in this setting. As a result, for select (transplant eligible) patients, allogeneic transplant should be strongly considered soon after ibrutinib response is documented to provide durable responses. Copyright © 2017 John Wiley & Sons, Ltd.
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Conductivity is a measure of the ability of water to pass an electrical current. Because dissolved salts and other inorganic chemicals conduct electrical current, conductivity increases as salinity increases.
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Biodesulfurization of refractory organic sulfur compounds in fossil fuels.
Soleimani, Mehran; Bassi, Amarjeet; Margaritis, Argyrios
2007-01-01
The stringent new regulations to lower sulfur content in fossil fuels require new economic and efficient methods for desulfurization of recalcitrant organic sulfur. Hydrodesulfurization of such compounds is very costly and requires high operating temperature and pressure. Biodesulfurization is a non-invasive approach that can specifically remove sulfur from refractory hydrocarbons under mild conditions and it can be potentially used in industrial desulfurization. Intensive research has been conducted in microbiology and molecular biology of the competent strains to increase their desulfurization activity; however, even the highest activity obtained is still insufficient to fulfill the industrial requirements. To improve the biodesulfurization efficiency, more work is needed in areas such as increasing specific desulfurization activity, hydrocarbon phase tolerance, sulfur removal at higher temperature, and isolating new strains for desulfurizing a broader range of sulfur compounds. This article comprehensively reviews and discusses key issues, advances and challenges for a competitive biodesulfurization process.
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Sharp Refractory Composite Leading Edges on Hypersonic Vehicles
NASA Technical Reports Server (NTRS)
Walker, Sandra P.; Sullivan, Brian J.
2003-01-01
On-going research of advanced sharp refractory composite leading edges for use on hypersonic air-breathing vehicles is presented in this paper. Intense magnitudes of heating and of heating gradients on the leading edge lead to thermal stresses that challenge the survivability of current material systems. A fundamental understanding of the problem is needed to further design development. Methodology for furthering the technology along with the use of advanced fiber architectures to improve the thermal-structural response is explored in the current work. Thermal and structural finite element analyses are conducted for several advanced fiber architectures of interest. A tailored thermal shock parameter for sharp orthotropic leading edges is identified for evaluating composite material systems. The use of the tailored thermal shock parameter has the potential to eliminate the need for detailed thermal-structural finite element analyses for initial screening of material systems being considered for a leading edge component.
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Effect of Different Structural Materials on Neutronic Performance of a Hybrid Reactor
NASA Astrophysics Data System (ADS)
Übeyli, Mustafa; Tel, Eyyüp
2003-06-01
Selection of structural material for a fusion-fission (hybrid) reactor is very important by taking into account of neutronic performance of the blanket. Refractory metals and alloys have much higher operating temperatures and neutron wall load (NWL) capabilities than low activation materials (ferritic/martensitic steels, vanadium alloys and SiC/SiC composites) and austenitic stainless steels. In this study, effect of primary candidate refractory alloys, namely, W-5Re, T111, TZM and Nb-1Zr on neutronic performance of the hybrid reactor was investigated. Neutron transport calculations were conducted with the help of SCALE 4.3 System by solving the Boltzmann transport equation with code XSDRNPM. Among the investigated structural materials, tantalum had the worst performance due to the fact that it has higher neutron absorption cross section than others. And W-5Re and TZM having similar results showed the best performance.
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Application of Carbon Composite Bricks for Blast Furnace Hearth
NASA Astrophysics Data System (ADS)
Zuo, Haibin; Wang, Cong; Zhang, Jianliang; Zhao, Yongan; Jiao, Kexin
Traditional refractory materials for blast furnace hearth lining are mainly composed of carbon bricks and the ceramic cup. However, these materials can't meet the demands for long service life design of blast furnaces. In this paper, a new refractory called carbon composite brick (CCB) was introduced, which combined the advantages of carbon bricks and the ceramic cup. In this case, the resistance of the CCB against corrosion was equal to the ceramic cup and the thermal conductivity of the CCB was equal to carbon bricks. From the results of more than 20 blast furnaces, the CCB could be well used in small blast furnaces and large blast furnaces. In the bad condition of low grade burden and high smelting intensity, the CCB gave full play to the role of cooling system, and effectively resisted the erosion of hot metal to improve the service life of blast furnaces.
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Shin, Yun Kyoung; Cho, Yang Seok; Lien, Mei-Ching; Proctor, Robert W
2007-09-01
It has been argued that the psychological refractory period (PRP) effect is eliminated with two ideomotor compatible tasks when instructions stress fast and simultaneous responding. Three experiments were conducted to test this hypothesis. In all experiments, Task 1 required spatially compatible manual responses (left or right) to the direction of an arrow, and Task 2 required saying the name of the auditory letter A or B. In Experiments 1 and 3, the manual responses were keypresses made with the left and right hands, whereas in Experiment 2 they were left-right toggle-switch movements made with the dominant hand. Instructions that stressed response speed reduced reaction time and increased error rate compared to standard instructions to respond fast and accurately, but did not eliminate the PRP effect on Task 2 reaction time. These results imply that, even when response speed is emphasized, ideomotor compatible tasks do not bypass response selection.
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Deep brain stimulation for psychiatric disorders: Is there an impact on social functioning?
Saleh, Christian; Hasler, Gregor
2017-01-01
Background: Deep brain stimulation (DBS) for refractory psychiatric disorders shows promising effects on symptom-reduction, however, little is known regarding the effects of DBS on social outcome. Methods: A PubMed search based on original studies of DBS for psychiatric disorders [treatment resistant depression (TRD), Gilles de la Tourette's syndrome (GTS), and obsessive compulsive disorder (OCD)] was conducted. Data on social outcome following surgery were extracted and analyzed. Results: Social functioning was not a primary outcome measure in the reviewed article. The literature is incomplete and inconclusive on this variable, however from the reported data, there is some evidence that DBS has the potential to improve social functioning. Conclusions: More systematic and detailed data gathering and reporting on social outcome with longer follow-ups are needed to evaluate more exhaustively the role of DBS in refractory psychiatric disorders. PMID:28781911
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Microstructure and Properties of Zircon-Added Carbon Refractories for Blast Furnace
NASA Astrophysics Data System (ADS)
Zhu, Tianbin; Li, Yawei; Sang, Shaobai; Chen, Xilai; Zhao, Lei; Li, Yuanbing; Li, Shujing
2012-11-01
Microstructure and properties of zircon-added carbon refractory specimens for blast furnace (BF) were investigated with the aid of X-ray diffraction (XRD), a scanning electron microscope (SEM), energy-dispersive X-ray, mercury porosimetry, and a laser thermal conductivity (TC) meter. Additives could influence the matrix structures and improve the properties of specimens. With the increase of zircon powder content, the amount of SiC whiskers formed increased and their aspect ratio became larger, and the SiC whiskers tended to be distributed homogeneously. Zircon powder additions decreased the mean pore diameter and increased <1- μm pore volume by filling in pores via SiC, improved the TC and the cold crushing strength (CCS) due to the in-situ formation of the more well-developed SiC whiskers with high TC, and significantly reduced the molten iron attack to carbon specimens.
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Diagnosis and management of refractory celiac disease: a systematic review.
Labidi, Asma; Serghini, Meriem; Karoui, Sami; Boubaker, Jalel; Filali, Azza
2013-01-01
Refractory celiac disease is defined by persisting malabsorptive symptoms in spite of a strict gluten free diet for at least 6 to 12 months. Alternatives to gluten free diet seem to be still controversial. To describe the clinical and epidemiologic aspects of refractory celiac disease, and to identify therapeutic options in this condition. Systematic review and critical analysis of observational studies, clinical trials and case reports that focused on diagnosis and management of refractory celiac disease. Refractory celiac disease can be classified as type 1 or type 2 according to the phenotype of intraepithelial lymphocytes. Great complications such as enteropathy-associated T-cell lymphoma may occur in a subgroup of these patients mainly in refractory celiac disease type 2. Curative therapies are still lacking. Refractory celiac disease remains a diagnosis of exclusion. Its prognosis remains still dismal by the absence yet of curative therapies. However, some new treatments seem to hold promise during few cohort-studies.
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Treatment of coking wastewater by a novel electric assisted micro-electrolysis filter.
Xie, Ruosong; Wu, Miaomiao; Qu, Guangfei; Ning, Ping; Cai, Yingying; Lv, Pei
2018-04-01
A newly designed electric assisted micro-electrolysis filter (E-ME) was developed to investigate its degradation efficiency for coking wastewater and correlated characteristics. The performance of the E-ME system was compared with separate electrolysis (SE) and micro-electrolysis (ME) systems. The results showed a prominent synergistic effect on COD removal in E-ME systems. Gas chromatography/mass spectrometry (GC-MS) analysis confirmed that the applied electric field enhanced the degradation of phenolic compounds. Meanwhile, more biodegradable oxygen-bearing compounds were detected. SEM images of granular activated carbon (GAC) showed that inactivation and blocking were inhibited during the E-ME process. The effects of applied voltage and initial pH in E-ME systems were also studied. The best voltage value was 1V, but synergistic effects existed even with lower applied voltage. E-ME systems exhibited some pH buffering capacity and attained the best efficiency in neutral media, which means that there is no need to adjust pH prior to or during the treatment process. Therefore, E-ME systems were confirmed as a promising technology for treatment of coking wastewater and other refractory wastewater. Copyright © 2017. Published by Elsevier B.V.
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2018-04-06
Folliculotropic Mycosis Fungoides; Recurrent Cutaneous T-Cell Non-Hodgkin Lymphoma; Recurrent Mycosis Fungoides; Refractory Cutaneous T-Cell Non-Hodgkin Lymphoma; Refractory Mycosis Fungoides; Refractory Peripheral T-Cell Lymphoma, Not Otherwise Specified; Sezary Syndrome; Recurrent Mature T- and NK-Cell Non-Hodgkin Lymphoma
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von Tresckow, Bastian; Engert, Andreas
2013-09-01
Despite the advances in the treatment of Hodgkin Lymphoma, patients with refractory disease still have a poor prognosis. Hodgkin Lymphoma can be refractory at first diagnosis or might become refractory later in the course of treatment. Both situations represent a therapeutic challenge. Intensified chemotherapy with BEACOPP escalated has been evaluated in early unfavourable and advanced Hodgkin Lymphoma and led to an improved tumour control and reduced rates of refractory disease. Furthermore, there is growing evidence for the role of tandem autologous transplant in breaking refractory disease. For patients relapsing after autologous transplant, more recent analyses have reported outcome and defined risk factors. The antibody drug conjugate brentuximab vedotin is a new, highly effective therapeutic option for these patients. Dose-reduced allogeneic transplant is a therapeutic alternative for patients relapsing after autologous transplant, but induction of a remission is the prerequisite for a successful allogeneic transplant. Brentuximab vedotin has been evaluated as a bridge to allogeneic transplant for patients refractory to conventional treatment. Recent therapeutic advances have improved the prognosis of Hodgkin Lymphoma by prevention or successful treatment of refractory disease. The use of new drugs such as brentuximab vedotin will hopefully further increase the cure rates.
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Method and Apparatus for Obtaining a Precision Thickness in Semiconductor and Other Wafers
NASA Technical Reports Server (NTRS)
Okojie, Robert S. (Inventor)
2002-01-01
A method and apparatus for processing a wafer comprising a material selected from an electrical semiconducting material and an electrical insulating material is presented. The wafer has opposed generally planar front and rear sides and a peripheral edge, wherein said wafer is pressed against a pad in the presence of a slurry to reduce its thickness. The thickness of the wafer is controlled by first forming a recess such as a dimple on the rear side of the wafer. A first electrical conducting strip extends from a first electrical connection means to the base surface of the recess to the second electrical connector. The first electrical conducting strip overlies the base surface of the recess. There is also a second electrical conductor with an electrical potential source between the first electrical connector and the second electrical connector to form. In combination with the first electrical conducting strip, the second electrical conductor forms a closed electrical circuit, and an electrical current flows through the closed electrical circuit. From the front side of the wafer the initial thickness of the wafer is reduced by lapping until the base surface of the recess is reached. The conductive strip is at least partially removed from the base surface to automatically stop the lapping procedure and thereby achieve the desired thickness.
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Embedded Heaters for Joining or Separating Plastic Parts
NASA Technical Reports Server (NTRS)
Bryant, Melvin A., III
2004-01-01
A proposed thermal-bonding technique would make it possible to join or separate thermoplastic parts quickly and efficiently. The technique would eliminate the need for conventional welding or for such conventional fastening components as bolted flanges or interlocking hooks. The technique could be particularly useful in the sign industry (in which large quantities of thermoplastics are used) or could be used to join plastic pipes. A thin sheet of a suitable electrically conductive material would be formed to fit between two thermoplastic parts to be joined (see figure). The electrically conductive sheet and the two parts would be put together tightly, then an electrical current would be sent through the conductor to heat the thermoplastic locally. The magnitude of the current and the heating time would be chosen to generate just enough heat to cause the thermoplastic to adhere to both sides of the electrically conductive sheet. Optionally, the electrically conductive sheet could contain many small holes to provide purchase or to increase electrical resistance to facilitate the generation of heat. After thermal bonding, the electrically conductive sheet remains as an integral part of the structure. If necessary, the electrically conductive sheet can be reheated later to separate the joined thermoplastic parts.
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Electrical Conductivity of Ferritin Proteins by Conductive AFM
NASA Technical Reports Server (NTRS)
Xu, Degao; Watt, Gerald D.; Harb, John N.; Davis, Robert C.
2005-01-01
Electrical conductivity measurements were performed on single apoferritin and holoferritin molecules by conductive atomic force microscopy. Conductivity of self-assembled monolayer films of ferritin molecules on gold surfaces was also measured. Holoferritin was 5-25 times more conductive than apoferritin, indicating that for holoferritin most electron-transfer goes through the ferrihydrite core. With 1 V applied, the average electrical currents through single holoferritin and apoferritin molecules were 2.6 PA and 0.19 PA, respectively.
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Modeling of electric field distribution in tissues during electroporation
2013-01-01
Background Electroporation based therapies and treatments (e.g. electrochemotherapy, gene electrotransfer for gene therapy and DNA vaccination, tissue ablation with irreversible electroporation and transdermal drug delivery) require a precise prediction of the therapy or treatment outcome by a personalized treatment planning procedure. Numerical modeling of local electric field distribution within electroporated tissues has become an important tool in treatment planning procedure in both clinical and experimental settings. Recent studies have reported that the uncertainties in electrical properties (i.e. electric conductivity of the treated tissues and the rate of increase in electric conductivity due to electroporation) predefined in numerical models have large effect on electroporation based therapy and treatment effectiveness. The aim of our study was to investigate whether the increase in electric conductivity of tissues needs to be taken into account when modeling tissue response to the electroporation pulses and how it affects the local electric distribution within electroporated tissues. Methods We built 3D numerical models for single tissue (one type of tissue, e.g. liver) and composite tissue (several types of tissues, e.g. subcutaneous tumor). Our computer simulations were performed by using three different modeling approaches that are based on finite element method: inverse analysis, nonlinear parametric and sequential analysis. We compared linear (i.e. tissue conductivity is constant) model and non-linear (i.e. tissue conductivity is electric field dependent) model. By calculating goodness of fit measure we compared the results of our numerical simulations to the results of in vivo measurements. Results The results of our study show that the nonlinear models (i.e. tissue conductivity is electric field dependent: σ(E)) fit experimental data better than linear models (i.e. tissue conductivity is constant). This was found for both single tissue and composite tissue. Our results of electric field distribution modeling in linear model of composite tissue (i.e. in the subcutaneous tumor model that do not take into account the relationship σ(E)) showed that a very high electric field (above irreversible threshold value) was concentrated only in the stratum corneum while the target tumor tissue was not successfully treated. Furthermore, the calculated volume of the target tumor tissue exposed to the electric field above reversible threshold in the subcutaneous model was zero assuming constant conductivities of each tissue. Our results also show that the inverse analysis allows for identification of both baseline tissue conductivity (i.e. conductivity of non-electroporated tissue) and tissue conductivity vs. electric field (σ(E)) of electroporated tissue. Conclusion Our results of modeling of electric field distribution in tissues during electroporation show that the changes in electrical conductivity due to electroporation need to be taken into account when an electroporation based treatment is planned or investigated. We concluded that the model of electric field distribution that takes into account the increase in electric conductivity due to electroporation yields more precise prediction of successfully electroporated target tissue volume. The findings of our study can significantly contribute to the current development of individualized patient-specific electroporation based treatment planning. PMID:23433433
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Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.
Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis
2016-05-01
Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front.
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Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges
Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis
2016-01-01
Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10−3 S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10−1 S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front. PMID:27386526
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Chemical Detection using Electrically Open Circuits having no Electrical Connections
NASA Technical Reports Server (NTRS)
Woodward, Stanley E.; Olgesby, Donald M.; Taylor, Bryant D.; Shams, Qamar A.
2008-01-01
This paper presents investigations to date on chemical detection using a recently developed method for designing, powering and interrogating sensors as electrically open circuits having no electrical connections. In lieu of having each sensor from a closed circuit with multiple electrically connected components, an electrically conductive geometric pattern that is powered using oscillating magnetic fields and capable of storing an electric field and a magnetic field without the need of a closed circuit or electrical connections is used. When electrically active, the patterns respond with their own magnetic field whose frequency, amplitude and bandwidth can be correlated with the magnitude of the physical quantities being measured. Preliminary experimental results of using two different detection approaches will be presented. In one method, a thin film of a reactant is deposited on the surface of the open-circuit sensor. Exposure to a specific targeted reactant shifts the resonant frequency of the sensor. In the second method, a coating of conductive material is placed on a thin non-conductive plastic sheet that is placed over the surface of the sensor. There is no physical contact between the sensor and the electrically conductive material. When the conductive material is exposed to a targeted reactant, a chemical reaction occurs that renders the material non-conductive. The change in the material s electrical resistance within the magnetic field of the sensor alters the sensor s response bandwidth and amplitude, allowing detection of the reaction without having the reactants in physical contact with the sensor.
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NASA Astrophysics Data System (ADS)
Pradipto, Abdul-Muizz; Akiyama, Toru; Ito, Tomonori; Nakamura, Kohji
2018-01-01
The effects of applying external electric fields to the anomalous and spin Hall conductivities in Fe thin-film models with different layer thicknesses on MgO(001) are investigated by using first-principles calculations. We observe that, for the considered systems, the application of positive electric field associated with the accumulation of negative charges on the Fe side generally decreases (increases) the anomalous (spin) Hall conductivities. The mapping of the Hall conductivities within the two-dimensional Brillouin zone shows that the electric-field-induced modifications are related to the modification of the band structures of the atoms at the interface with the MgO substrate. In particular, the external electric field affects the Hall conductivities via the modifications of the dx z,dy z orbitals, in which the application of positive electric field pushes the minority-spin states of the dx z,dy z bands closer to the Fermi level. Better agreement with the anomalous Hall conductivity for bulk Fe and a more realistic scenario for the electric field modification of Hall conductivities are obtained by using the thicker layers of Fe on MgO (Fe3/MgO and Fe5/MgO).
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Non-permeable substrate carrier for electroplating
Abas, Emmanuel Chua; Chen, Chen-An; Ma, Diana Xiaobing; Ganti, Kalyana Bhargava
2012-11-27
One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The substrate carrier comprises a non-conductive carrier body on which the substrates are to be held. Electrically-conductive lines are embedded within the carrier body, and a plurality of contact clips are coupled to the electrically-conductive lines embedded within the carrier body. The contact clips hold the substrates in place and electrically couple the substrates to the electrically-conductive lines. The non-conductive carrier body is continuous so as to be impermeable to flow of electroplating solution through the non-conductive carrier body. Other embodiments, aspects and features are also disclosed.
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Non-permeable substrate carrier for electroplating
Abas, Emmanuel Chua; Chen, Chen-an; Ma, Diana Xiaobing; Ganti, Kalyana; Divino, Edmundo Anida; Ermita, Jake Randal G.; Capulong, Jose Francisco S.; Castillo, Arnold Villamor
2015-12-29
One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The substrate carrier comprises a non-conductive carrier body on which the substrates are to be held. Electrically-conductive lines are embedded within the carrier body, and a plurality of contact clips are coupled to the electrically-conductive lines embedded within the carrier body. The contact clips hold the substrates in place and electrically couple the substrates to the electrically-conductive lines. The non-conductive carrier body is continuous so as to be impermeable to flow of electroplating solution through the non-conductive carrier body. Other embodiments, aspects and features are also disclosed.
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Electrical Investigation of Metal-Olivine Systems and Application to the Deep Interior of Mercury
NASA Astrophysics Data System (ADS)
Zhang, Zhou; Pommier, Anne
2017-12-01
We report electrical conductivity measurements on metal-olivine systems at about 5 and 6 GPa and up to 1,675°C in order to investigate the electrical properties of core-mantle boundary (CMB) systems. Electrical experiments were conducted in the multianvil apparatus using the impedance spectroscopy technique. The samples are composed of one metal layer (Fe, FeS, FeSi2, or Fe-Ni-S-Si) and one polycrystalline olivine layer, with the metal:olivine ratio ranging from 1:0.7 to 1:9.2. For all samples, we observe that the bulk electrical conductivity increases with temperature from 10-2.5 to 101.8 S/m, which is higher than the conductivity of polycrystalline olivine but lower than the conductivity of the pure metal phase at similar conditions. In some experiments, a conductivity jump is observed at the temperature corresponding to the melting temperature of the metallic phase. Both the metal:olivine ratio and the metal phase geometry control the electrical conductivity of the two-layer samples. By combining electrical results, textural analyses of the samples, and previous studies of the structure and composition of Mercury's interior, we propose an electrical profile of the deep interior of the planet that accounts for a layered CMB-outer core structure. The electrical model agrees with existing conductivity estimates of Mercury's lower mantle and CMB using magnetic observations and thermodynamic calculations, and thus, supports the hypothesis of a layered CMB-outermost core structure in the present-day interior of Mercury. We propose that the layered CMB-outer core structure is possibly electrically insulating, which may influence the planet's structure and cooling history.
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Stanis, Ronald J.; Lambert, Timothy N.
2016-12-06
An apparatus of an aspect includes a fuel cell catalyst layer. The fuel cell catalyst layer is operable to catalyze a reaction involving a fuel reactant. A fuel cell gas diffusion layer is coupled with the fuel cell catalyst layer. The fuel cell gas diffusion layer includes a porous electrically conductive material. The porous electrically conductive material is operable to allow the fuel reactant to transfer through the fuel cell gas diffusion layer to reach the fuel cell catalyst layer. The porous electrically conductive material is also operable to conduct electrons associated with the reaction through the fuel cell gas diffusion layer. An electrically conductive polymer material is coupled with the fuel cell gas diffusion layer. The electrically conductive polymer material is operable to limit transfer of the fuel reactant to the fuel cell catalyst layer.
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Method of forming electrical pathways in indium-tin-oxide coatings
Haynes, T.E.
1996-12-03
An electrical device includes a substrate having an ITO coating thereon, a portion of which is conductive and defines at least one electrical pathway, and the balance of the ITO being insulative. The device is made by the following general steps: a. providing a substrate having a conductive ITO coating on at least one surface thereof; b. rendering a preselected portion of the coating of conductive ITO insulative, leaving the remaining portion of conductive ITO as at least one electrical pathway. 8 figs.
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Method of forming electrical pathways in indium-tin-oxide coatings
Haynes, T.E.
1997-03-04
An electrical device includes a substrate having an ITO coating thereon, a portion of which is conductive and defines at least one electrical pathway, the balance of the ITO being insulative. The device is made by the following general steps: (a) providing a substrate having a conductive ITO coating on at least one surface thereof; (b) rendering a preselected portion of the coating of conductive ITO insulative, leaving the remaining portion of conductive ITO as at least one electrical pathway. 8 figs.
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Method of forming electrical pathways in indium-tin-oxide coatings
Haynes, Tony E.
1996-01-01
An electrical device includes a substrate having an ITO coating thereon, a portion of which is conductive and defines at least one electrical pathway, and the balance of the ITO being insulative. The device is made by the following general steps: a. providing a substrate having a conductive ITO coating on at least one surface thereof; b. rendering a preselected portion of the coating of conductive ITO insulative, leaving the remaining portion of conductive ITO as at least one electrical pathway.
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Method of forming electrical pathways in indium-tin-oxide coatings
Haynes, Tony E.
1997-01-01
An electrical device includes a substrate having an ITO coating thereon, a portion of which is conductive and defines at least one electrical pathway, and the balance of the ITO being insulative. The device is made by the following general steps: a. providing a substrate having a conductive ITO coating on at least one surface thereof; b. rendering a preselected portion of the coating of conductive ITO insulative, leaving the remaining portion of conductive ITO as at least one electrical pathway.
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2018-06-25
CD20 Positive; Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Mediastinal (Thymic) Large B-Cell Cell Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Mediastinal (Thymic) Large B-Cell Cell Lymphoma; Transformed Recurrent Non-Hodgkin Lymphoma
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Spent refractory reuse as a slag conditioning additive in the EAF
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bennett, James P.; Kwong, Kyei-Sing; Krabbe, Rick
2000-01-01
Refractories removed from service in EAF applications are typically landfilled. A joint USDOE and Steel Manufacturers Association program involving industrial cooperators is evaluating spent refractory recycling/reuse. A review of current recycling practices and a review of progress towards controlling EAF slag chemistry and properties with the additions of basic spent refractories will be discussed.
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2018-06-25
Advanced Malignant Solid Neoplasm; Ann Arbor Stage III Childhood Non-Hodgkin Lymphoma; Ann Arbor Stage IV Childhood Non-Hodgkin Lymphoma; BRAF Gene Mutation; GNA11 Gene Mutation; GNAQ Gene Mutation; Histiocytosis; HRAS Gene Mutation; KRAS Gene Mutation; NF1 Gene Mutation; NRAS Gene Mutation; Recurrent Childhood Central Nervous System Neoplasm; Recurrent Childhood Non-Hodgkin Lymphoma; Recurrent Malignant Solid Neoplasm; Recurrent Neuroblastoma; Refractory Central Nervous System Neoplasm; Refractory Malignant Solid Neoplasm; Refractory Neuroblastoma; Refractory Non-Hodgkin Lymphoma
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Electrical conductivity of rocks at high pressures and temperatures
NASA Technical Reports Server (NTRS)
Parkhomenko, E. I.; Bondarenko, A. T.
1986-01-01
The results of studies of the electrical conductivity in the most widely distributed types of igneous rocks, at temperatures of up to 1200 C, at atmospheric pressure, and also at temperatures of up to 700 C and at pressures of up to 20,000 kg/sq cm are described. The figures of electrical conductivity, of activaation energy and of the preexponential coefficient are presented and the dependence of these parameters on the petrochemical parameters of the rocks are reviewed. The possible electrical conductivities for the depository, granite and basalt layers of the Earth's crust and of the upper mantle are presented, as well as the electrical conductivity distribution to the depth of 200 to 240 km for different geological structures.
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Bogachev, Igor; Yudin, Artem; Grigoryev, Evgeniy; ...
2015-11-02
Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10–15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining themore » initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. As a result, the choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.« less
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Brandt, A; Gulba, D C
2006-12-01
Myocardial ischemia induces redistribution of different ions (H(+), K(+), Na(+), Ca(++)) across the cardiomyocyte membrane, as well as the loss of intracellular ATP content. This results in changes in the electrical properties including shortening of the action potential, appearance of delayed afterpotentials, and a modified refractoriness of the cardiomyocyte. These changes may induce or support malignant cardiac arrhythmias. Supersensitivity of sympathetic denervated myocardium may further support the electrical instability of ischemic myocardium.Virtues of studies indicate that patients with coronary artery disease who develop complex arrhythmias during or after exercise bear a substantially increased risk for sudden cardiac death. Other studies report about arrhythmic stabilization and reduced mortality if patients with reversible myocardial ischemia receive complete revascularization. However, none of these studies is without methodological flaws. Due to the lack of methodologically sound studies in sufficiently large patient cohorts, the question whether complete coronary revascularisation improves the prognosis of patients with coronary artery disease and which strategy (medical, interventional, or surgical) warrants the best outcomes remains open.
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Bogachev, Igor; Yudin, Artem; Grigoryev, Evgeniy; Chernov, Ivan; Staltsov, Maxim; Khasanov, Oleg; Olevsky, Eugene
2015-11-02
Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10-15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining the initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. The choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.
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RF transmission line and drill/pipe string switching technology for down-hole telemetry
Clark, David D [Santa Fe, NM; Coates, Don M [Santa Fe, NM
2007-08-14
A modulated reflectance well telemetry apparatus having an electrically conductive pipe extending from above a surface to a point below the surface inside a casing. An electrical conductor is located at a position a distance from the electrically conductive pipe and extending from above the surface to a point below the surface. Modulated reflectance apparatus is located below the surface for modulating well data into a RF carrier transmitted from the surface and reflecting the modulated carrier back to the surface. A RF transceiver is located at the surface and is connected between the electrically conductive pipe and the electrical conductor for transmitting a RF signal that is confined between the electrically conductive well pipe and the electrical conductor to the modulated reflectance apparatus, and for receiving reflected data on the well from the modulated reflectance apparatus.
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Electrical conductivity behavior of Gum Arabic biopolymer-Fe3O4 nanocomposites
NASA Astrophysics Data System (ADS)
Bhakat, D.; Barik, P.; Bhattacharjee, A.
2018-01-01
Present work reports a study on the electrical conduction properties of some composites of Gum Arabic biopolymer and magnetite nanoparticles as host and guest, respectively, synthesized in different weight percentages. The nanocomposites are found to be non-extrinsic type of semiconductors with guest content dependent trap distribution of charge carriers. Conductivity of these materials increases with increasing guest content along with a concomitant decrease in the activation energy. Percolation theory has been employed for the analysis of the electrical conductivity results to explore the effect of the guest on the electrical conductivity of the host.
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Influence of temperature on the electrical conductivity of leachate from municipal solid waste.
Grellier, Solenne; Robain, Henri; Bellier, Gérard; Skhiri, Nathalie
2006-09-01
A bioreactor landfill is designed to manage municipal solid waste, through accelerated waste biodegradation, and stabilisation of the process by means of the controlled addition of liquid, i.e. leachate recirculation. The measurement of electrical resistivity by Electrical Resistivity Tomography (ERT) allows to monitor water content present in the bioreactors. Variations in electrical resistivity are linked to variations in moisture content and temperature. In order to overcome this ambiguity, two laboratory experiments were carried out to establish a relationship between temperature and electrical conductivity: the first set of measurements was made for leachate alone, whereas the second set was made with two different granular media saturated with leachate. Both experiments confirm a well known increase in conductivity of about 2% degrees C(-1). However, higher suspended matter concentrations lead to a lower dependence of electrical conductivity on temperature. Furthermore, for various porous media saturated with an identical leachate, the higher the specific surface of the granular matrix, the lower the effective bulk electrical conductivity. These observations show that a correct understanding of the electrical properties of liquids requires the nature and (in particular) the size of the electrical charge carriers to be taken into account.
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Atrioventricular node functional remodeling induced by atrial fibrillation.
Zhang, Youhua; Mazgalev, Todor N
2012-09-01
The atrioventricular node (AVN) plays a vital role in determining the ventricular rate during atrial fibrillation (AF). AF results in profound electrophysiological and structural remodeling in the atria as well as the sinus node. However, it is unknown whether AVN undergoes remodeling during AF. To determine whether AVN undergoes functional remodeling during AF. AVN conduction properties were studied in vitro in 9 rabbits with AF and 10 normal controls. A previously validated index of AVN dual-pathway electrophysiology, His-electrogram alternans, was used to monitor fast-pathway or slow-pathway (SP) AVN conduction in these experiments. AVN conduction properties were further studied in vivo in 7 dogs with chronic AF and 8 controls. Compared with the control rabbits, the rabbits with AF had a longer AVN conduction time (83 ± 16 ms vs 68 ± 7 ms; P <.01), longer AVN effective refractory period (141 ± 27 ms vs 100 ± 9 ms; P <.01), an earlier transition from fast-pathway to SP conduction (at a longer prematurity, 249 ± 60 ms vs 171 ± 24 ms; P <.01), and a slower ventricular rate during simulated AF (RR interval 249 ± 42 ms vs 202 ± 12 ms; P <.01). Notably, a larger proportion of conducted beats utilized the SP in AF preparations (92% ± 12% vs 63% ± 32%; P <.05). Long-term AF in dogs resulted in a longer atrioventricular conduction time and AVN effective refractory period and a slower ventricular rate during AF compared with the controls. Pronounced AVN functional electrophysiological remodeling occurs after long-term AF, which could lead to a spontaneous slowing of the ventricular rate. Furthermore, the SP dominance during AF underscores the effectiveness of its modification by ablation for ventricular rate control during AF. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.
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Young Investigator Program: Quasi-Liquid Grain Boundary Films in Refractory Metals
2010-01-15
have been conducted for W using various dopants with significantly different effectiveness [48, 52], enabling a critical test of the hypothesized...thickness vs. temperature for dopant -saturated W specimens. (b) The experimental sintering (densification) rates. Reprinted from an AFOSR supported...the colloidal theory (Fig. 16b). The basic concepts can be explained as follows. By reducing the temperature, or dopant activity, a quasi-liquid
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NASA Astrophysics Data System (ADS)
Jougnot, Damien; Jiménez-Martínez, Joaquín; Legendre, Raphaël; Le Borgne, Tanguy; Méheust, Yves; Linde, Niklas
2018-03-01
Time-lapse electrical resistivity tomography (ERT) is a geophysical method widely used to remotely monitor the migration of electrically-conductive tracers and contaminant plumes in the subsurface. Interpretations of time-lapse ERT inversion results are generally based on the assumption of a homogeneous solute concentration below the resolution limits of the tomogram depicting inferred electrical conductivity variations. We suggest that ignoring small-scale solute concentration variability (i.e., at the sub-resolution scale) is a major reason for the often-observed apparent loss of solute mass in ERT tracer studies. To demonstrate this, we developed a geoelectrical milli-fluidic setup where the bulk electric conductivity of a 2D analogous porous medium, consisting of cylindrical grains positioned randomly inside a Hele-Shaw cell, is monitored continuously in time while saline tracer tests are performed through the medium under fully and partially saturated conditions. High resolution images of the porous medium are recorded with a camera at regular time intervals, and provide both the spatial distribution of the fluid phases (aqueous solution and air), and the saline solute concentration field (where the solute consists of a mixture of salt and fluorescein, the latter being used as a proxy for the salt concentration). Effective bulk electrical conductivities computed numerically from the measured solute concentration field and the spatial distributions of fluid phases agree well with the measured bulk conductivities. We find that the effective bulk electrical conductivity is highly influenced by the connectivity of high electrical conductivity regions. The spatial distribution of air, saline tracer fingering, and mixing phenomena drive temporal changes in the effective bulk electrical conductivity by creating preferential paths or barriers for electrical current at the pore-scale. The resulting heterogeneities in the solute concentrations lead to strong anisotropy of the effective bulk electrical conductivity, especially for partially saturated conditions. We highlight how these phenomena contribute to the typically large apparent mass loss observed when conducting field-scale time-lapse ERT.
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Double anisotropic electrically conductive flexible Janus-typed membranes.
Li, Xiaobing; Ma, Qianli; Tian, Jiao; Xi, Xue; Li, Dan; Dong, Xiangting; Yu, Wensheng; Wang, Xinlu; Wang, Jinxian; Liu, Guixia
2017-12-07
Novel type III anisotropic conductive films (ACFs), namely flexible Janus-typed membranes, were proposed, designed and fabricated for the first time. Flexible Janus-typed membranes composed of ordered Janus nanobelts were constructed by electrospinning, which simultaneously possess fluorescence and double electrically conductive anisotropy. For the fabrication of the Janus-typed membrane, Janus nanobelts comprising a conductive side and an insulative-fluorescent side were primarily fabricated, and then the Janus nanobelts are arranged into parallel arrays using an aluminum rotary drum as the collector to obtain a single anisotropically conductive film. Subsequently, a secondary electrospinning process was applied to the as-prepared single anisotropically conductive films to acquire the final Janus-typed membrane. For this Janus-typed membrane, namely its left-to-right structure, anisotropic electrical conduction synchronously exists on both sides, and furthermore, the two electrically conductive directions are perpendicular. By modulating the amount of Eu(BA) 3 phen complex and conducting polyaniline (PANI), the characteristics and intensity of the fluorescence-electricity dual-function in the membrane can be tuned. The high integration of this peculiar Janus-typed membrane with simultaneous double electrically conductive anisotropy-fluorescent dual-functionality is successfully realized in this study. This design philosophy and preparative technique will provide support for the design and construction of new types of special nanostructures with multi-functionality.
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NASA Astrophysics Data System (ADS)
Sheftman, D.; Shafer, D.; Efimov, S.; Krasik, Ya. E.
2012-03-01
Sub-microsecond timescale underwater electrical wire explosions using Cu and Al materials have been conducted. Current and voltage waveforms and time-resolved streak images of the discharge channel, coupled to 1D magneto-hydrodynamic simulations, have been used to determine the electrical conductivity of the metals for the range of conditions between hot liquid metal and strongly coupled non-ideal plasma, in the temperature range of 10-60 KK. The results of these studies showed that the conductivity values obtained are typically lower than those corresponding to modern theoretical electrical conductivity models and provide a transition between the conductivity values obtained in microsecond time scale explosions and those obtained in nanosecond time scale wire explosions. In addition, the measured wire expansion shows good agreement with equation of state tables.
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Febrile Infection-Related Epilepsy Syndrome (FIRES): An Overview of Treatment and Recent Patents.
Hon, Kam Lun E Lun; Leung, Alexander K C; Torres, Alcy R
2018-05-08
New-onset refractory status epilepticus (NORSE) refers to a clinical presentation in a patient without active epilepsy or other existing relevant neurological disorder, with new onset of refractory status epilepticus in the absence of a clear acute or active structural, metabolic, or toxic cause. Febrile infection-related epilepsy syndrome (FIRES) is a subset of NORSE that requires a febrile infection between 24 hours and 2 weeks prior to the onset of refractory status epilepticus, with or without fever at the onset of status epilepticus, and with no restriction to the age of the patient. The literature on FIRES is scarce. This article reviews the pathophysiology, clinical features, and various treatment modalities in the treatment of FIRES. A Medline/Pubmed search was conducted using Clinical Queries with the key terms "febrile infection-related epilepsy syndrome", "FIRES", "new-onset refractory status epilepticus" and "NORSE". The search strategy included meta-analyses, randomized controlled trials, clinical trials, reviews and pertinent references. Patents were searched using the key term "FIRES", "NORSE" and "febrile epilepsy syndrome" from www.google.com/patents, www.uspto.gov, and www.freepatentsonline.com. FIRES almost invariably begins with a mild nonspecific febrile illness in an otherwise healthy individual. Twenty four hours to two weeks later, seizures begin and quickly become very frequent and worsen, becoming status epilepticus. Seizures can be simple motor, complex partial or secondary generalized. The exact etiology is no known. It is possible that the syndrome is caused by an inflammatory or autoimmune mechanism. Seizures in FIRES are notoriously very difficult to treat. Treatment modalities include, among others, various antiepileptic drugs, ketogenic diet, intravenous corticosteroids, intravenous immunoglobulin, and burst-suppression coma. Outcome is poor; most children are left with significant cognitive disability and refractory epilepsy. Recent patents for the management of FIRES are discussed. FIRES is a rare epilepsy syndrome of unclear etiology in which children, usually of school age, suddenly develop very frequent seizures after a mild febrile illness. Seizures in FIRES are typically recalcitrant and difficult to treat. The prognosis is poor. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
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Method of imaging the electrical conductivity distribution of a subsurface
Johnson, Timothy C.
2017-09-26
A method of imaging electrical conductivity distribution of a subsurface containing metallic structures with known locations and dimensions is disclosed. Current is injected into the subsurface to measure electrical potentials using multiple sets of electrodes, thus generating electrical resistivity tomography measurements. A numeric code is applied to simulate the measured potentials in the presence of the metallic structures. An inversion code is applied that utilizes the electrical resistivity tomography measurements and the simulated measured potentials to image the subsurface electrical conductivity distribution and remove effects of the subsurface metallic structures with known locations and dimensions.
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Sensors for detecting analytes in fluids
NASA Technical Reports Server (NTRS)
Lewis, Nathan S. (Inventor); Severin, Erik (Inventor)
1998-01-01
Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.
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Sensors for detecting analytes in fluids
NASA Technical Reports Server (NTRS)
Severin, Erik (Inventor); Lewis, Nathan S. (Inventor)
2001-01-01
Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.
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Sensors for detecting analytes in fluids
NASA Technical Reports Server (NTRS)
Lewis, Nathan S. (Inventor); Severin, Erik (Inventor)
1999-01-01
Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.
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Sensor arrays for detecting analytes in fluids
NASA Technical Reports Server (NTRS)
Lewis, Nathan S. (Inventor); Freund, Michael S. (Inventor)
1996-01-01
Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g. electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.
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Transport properties of olivine grain boundaries from electrical conductivity experiments
NASA Astrophysics Data System (ADS)
Pommier, Anne; Kohlstedt, David L.; Hansen, Lars N.; Mackwell, Stephen; Tasaka, Miki; Heidelbach, Florian; Leinenweber, Kurt
2018-05-01
Grain boundary processes contribute significantly to electronic and ionic transports in materials within Earth's interior. We report a novel experimental study of grain boundary conductivity in highly strained olivine aggregates that demonstrates the importance of misorientation angle between adjacent grains on aggregate transport properties. We performed electrical conductivity measurements of melt-free polycrystalline olivine (Fo90) samples that had been previously deformed at 1200 °C and 0.3 GPa to shear strains up to γ = 7.3. The electrical conductivity and anisotropy were measured at 2.8 GPa over the temperature range 700-1400 °C. We observed that (1) the electrical conductivity of samples with a small grain size (3-6 µm) and strong crystallographic preferred orientation produced by dynamic recrystallization during large-strain shear deformation is a factor of 10 or more larger than that measured on coarse-grained samples, (2) the sample deformed to the highest strain is the most conductive even though it does not have the smallest grain size, and (3) conductivity is up to a factor of 4 larger in the direction of shear than normal to the shear plane. Based on these results combined with electrical conductivity data for coarse-grained, polycrystalline olivine and for single crystals, we propose that the electrical conductivity of our fine-grained samples is dominated by grain boundary paths. In addition, the electrical anisotropy results from preferential alignment of higher-conductivity grain boundaries associated with the development of a strong crystallographic preferred orientation of the grains.
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Electrically Conductive and Protective Coating for Planar SOFC Stacks
DOE Office of Scientific and Technical Information (OSTI.GOV)
Choi, Jung-Pyung; Stevenson, Jeffry W.
Ferritic stainless steels are preferred interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. However, this coating is not compatible with the formation of stable, hermetic seals between the interconnect frame component and the ceramic cell. Thus, a new aluminizing process has been developed by PNNL to enable durable sealing, preventmore » Cr evaporation, and maintain electrical insulation between stack repeat units. Hence, two different types of coating need to have stable operation of SOFC stacks. This paper will focus on the electrically conductive coating process. Moreover, an advanced coating process, compatible with a non-electrically conductive coating will be« less
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Method of fabricating high-density hermetic electrical feedthroughs
Shah, Kedar G.; Pannu, Satinderpall S.; Delima, Terri L.
2015-06-02
A method of fabricating electrical feedthroughs selectively removes substrate material from a first side of an electrically conductive substrate (e.g. a bio-compatible metal) to form an array of electrically conductive posts in a substrate cavity. An electrically insulating material (e.g. a bio-compatible sealing glass) is then flowed to fill the substrate cavity and surround each post, and solidified. The solidified insulating material is then exposed from an opposite second side of the substrate so that each post is electrically isolated from each other as well as the bulk substrate. In this manner a hermetic electrically conductive feedthrough construction is formed having an array of electrical feedthroughs extending between the first and second sides of the substrate from which it was formed.
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NASA Astrophysics Data System (ADS)
Ogawa, Emiyu; Arai, Tsunenori
2018-02-01
The time for electrical conduction blockade induced by a photodynamic reaction was studied on a myocardial cell wire in vitro and an in silico simulation model was constructed to understand the necessary time for electrical conduction blockade for the wire. Vulnerable state of the cells on a laser interaction would be an unstable and undesirable state since the cells might progress to completely damaged or repaired to change significantly therapeutic effect. So that in silico model, which can calculate the vulnerable cell state, is needed. Understanding an immediate electrical conduction blockade is needed for our proposed new methodology for tachyarrhythmia catheter ablation applying a photodynamic reaction. We studied the electrical conduction blockade occurrence on the electrical conduction wire made of cultured myocardial cells in a line shape and constructed in silico model based on this experimental data. The intracellular Ca2+ ion concentrations were obtained using Fluo-4 AM dye under a confocal laser microscope. A cross-correlation function was used for the electrical conduction blockade judgment. The photodynamic reaction was performed under the confocal microscopy with 3-120 mW/cm2 in irradiance by the diode laser with 663 nm in wavelength. We obtained that the time for the electrical conduction blockade decreased with the irradiance increasing. We constructed a simulation model composed of three states; living cells, vulnerable cells, and blocked cells, using the obtained experimental data and we found the rate constant by an optimization using a conjugate gradient method.
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NASA Astrophysics Data System (ADS)
Bourdo, Shawn Edward
Two groups of materials that have recently come to the forefront of research initiatives are carbon allotropes, especially nanotubes, and conducting polymers-more specifically inherently conducting polymers. The terms conducting polymers and inherently conducting polymers sometimes are used interchangeably without fully acknowledging a major difference in these terms. Conducting polymers (CPs) and inherently conducting polymers (ICPs) are both polymeric materials that conduct electricity, but the difference lies in how each of these materials conducts electricity. For CPs of the past, an electrically conductive filler such as metal particles, carbon black, or graphite would be blended into a polymer (insulator) allowing for the CP to carry an electric current. An ICP conducts electricity due to the intrinsic nature of its chemical structure. The two materials at the center of this research are graphite and polyaniline. For the first time, a composite between carbon allotropes (graphite) and an inherently conducting polymer (PANI) has exhibited an electrical conductivity greater than either of the two components. Both components have a plethora of potential applications and therefore the further investigation could lead to use of these composites in any number of technologies. Touted applications that use either conductive carbons or ICPs exist in a wide range of fields, including electromagnetic interference (EMI) shielding, radar evasion, low power rechargeable batteries, electrostatic dissipation (ESD) for anti-static textiles, electronic devices, light emitting diodes (LEDs), corrosion prevention, gas sensors, super capacitors, photovoltaic cells, and resistive heating. The main motivation for this research has been to investigate the connection between an observed increase in conductivity and structure of composites. Two main findings have resulted from the research as related to the observed increase in conductivity. The first was the structural evidence from Raman spectroscopy, X-ray diffraction, and thermal analysis suggesting a more crystalline graphite matrix due to intimate interactions with PANI that resulted in a charge transfer. Confirmation of charge transfer was observed through magnetic susceptibility, electron paramagnetic resonance, and temperature dependent electrical conductivity studies.