Antioxidant effects of water- and lipid-soluble nitroxide radicals in liposomes.

PubMed

Cimato, Alejandra N; Piehl, Lidia L; Facorro, Graciela B; Torti, Horacio B; Hager, Alfredo A

2004-12-15

Liposomes are today useful tools in different fields of science and technology. A lack of stability due to lipid peroxidation is the main problem in the extension of the use of these formulations. Recent investigative works have reported the protective effects of stable nitroxide radicals against oxidative processes in different media and under different stress conditions. Our group has focused its attention on the natural aging of liposomes and the protection provided by the water- and lipid-soluble nitroxide radicals 2,2,6,6-tetramethylpiperdine-1-oxyl (TEMPO) and doxylstearic acids (5-DSA, 12-DSA, and 16-DSA), respectively. Unilamellar liposomes were incubated under air atmosphere at 37 degrees C, both in the absence and in the presence of these radicals. Conjugated dienes, lipid hydroperoxides, TBARS, membrane fluidity, and nitroxide ESR signal intensity were followed as a function of time. Our results demonstrated that doxylstearic acids were more efficient than TEMPO in retarding lipid peroxidation at all the concentrations tested. The inhibition percentages, depending on the total nitroxide concentration, were not proportional to the lipid-water partition coefficient. Furthermore, time-course ESR signals showed a slower decrease for doxylstearic acids than for TEMPO. No significant differences were found among 5-DSA, 12-DSA, and 16-DSA. We concluded that the nitroxide radical efficiency as antioxidant directly depends on both nitroxide concentration and lipophilicity.

Electrolysis-driven bioremediation of crude oil-contaminated marine sediments.

PubMed

Bellagamba, Marco; Cruz Viggi, Carolina; Ademollo, Nicoletta; Rossetti, Simona; Aulenta, Federico

2017-09-25

Bioremediation is an effective technology to tackle crude oil spill disasters, which takes advantage of the capacity of naturally occurring microorganisms to degrade petroleum hydrocarbons under a range of environmental conditions. The enzymatic process of breaking down oil is usually more rapid in the presence of oxygen. However, in contaminated sediments, oxygen levels are typically too low to sustain the rapid and complete biodegradation of buried hydrocarbons. Here, we explored the possibility to electrochemically manipulate the redox potential of a crude oil-contaminated marine sediment in order to establish, in situ, conditions that are conducive to contaminants biodegradation by autochthonous microbial communities. The proposed approach is based on the exploitation of low-voltage (2V) seawater electrolysis to drive oxygen generation (while minimizing chlorine evolution) on Dimensionally Stable Anodes (DSA) placed within the contaminated sediment. Results, based on a laboratory scale setup with chronically polluted sediments spiked with crude oil, showed an increased redox potential and a decreased pH in the vicinity of the anode of 'electrified' treatments, consistent with the occurrence of oxygen generation. Accordingly, hydrocarbons biodegradation was substantially accelerated (up to 3-times) compared to 'non-electrified' controls, while sulfate reduction was severely inhibited. Intermittent application of electrolysis proved to be an effective strategy to minimize the energy requirements of the process, without adversely affecting degradation performance. Taken as a whole, this study suggests that electrolysis-driven bioremediation could be a sustainable technology for the management of contaminated sediments. Copyright © 2016 Elsevier B.V. All rights reserved.

Mechanism of Dynamic Strain Aging in a Niobium-Stabilized Austenitic Stainless Steel

NASA Astrophysics Data System (ADS)

Zhou, Hongwei; Bai, Fengmei; Yang, Lei; Wei, Hailian; Chen, Yan; Peng, Guosheng; He, Yizhu

2018-04-01

Dynamic strain aging (DSA) behavior of a niobium (Nb)-stabilized austenitic stainless steel (TP347H) was studied from room temperature (RT) to 973 K via tensile testing, transmission electron microscopy (TEM), and internal friction (IF) measurements. The DSA effect is nearly negligible from 573 K to 673 K, and it becomes significant at temperatures between 773 K and 873 K with strain rates of 3 × 10-3 s-1, 8 × 10-4 s-1, and 8 × 10-5 s-1, respectively. The results indicate that a dislocation planar slip is dominant in the strong DSA regime. The Snoek-like peak located at 625 K is highly sensitive to the diffusion of free carbon (C) atoms in solid solution. C-Nb octahedrons are formed by C chemical affinity to substitutional Nb solute atoms. Octahedron structure is very stable and captures most free C atoms and inhibits DSA at low tensile test temperatures of 573 K to 673 K. At high test temperatures in the range from 773 K to 873 K, C-Nb octahedrons break up and release free C and Nb atoms, resulting in the stronger Snoek-like peak. The interaction between C atoms and dislocations is responsible for DSA at low temperatures ranging from 573 K to 673 K. At higher temperature of 773 K to 873 K, the Cr and Nb atoms lock the dislocations, and this formation contributes to DSA.

Application of MOSFET detectors for dosimetry in small animal radiography using short exposure times.

PubMed

De Lin, Ming; Toncheva, Greta; Nguyen, Giao; Kim, Sangroh; Anderson-Evans, Colin; Johnson, G Allan; Yoshizumi, Terry T

2008-08-01

Digital subtraction angiography (DSA) X-ray imaging for small animals can be used for functional phenotyping given its ability to capture rapid physiological changes at high spatial and temporal resolution. The higher temporal and spatial requirements for small-animal imaging drive the need for short, high-flux X-ray pulses. However, high doses of ionizing radiation can affect the physiology. The purpose of this study was to verify and apply metal oxide semiconductor field effect transistor (MOSFET) technology to dosimetry for small-animal diagnostic imaging. A tungsten anode X-ray source was used to expose a tissue-equivalent mouse phantom. Dose measurements were made on the phantom surface and interior. The MOSFETs were verified with thermoluminescence dosimeters (TLDs). Bland-Altman analysis showed that the MOSFET results agreed with the TLD results (bias, 0.0625). Using typical small animal DSA scan parameters, the dose ranged from 0.7 to 2.2 cGy. Application of the MOSFETs in the small animal environment provided two main benefits: (1) the availability of results in near real-time instead of the hours needed for TLD processes and (2) the ability to support multiple exposures with different X-ray techniques (various of kVp, mA and ms) using the same MOSFET. This MOSFET technology has proven to be a fast, reliable small animal dosimetry method for DSA imaging and is a good system for dose monitoring for serial and gene expression studies.

Application of MOSFET Detectors for Dosimetry in Small Animal Radiography Using Short Exposure Times

PubMed Central

De Lin, Ming; Toncheva, Greta; Nguyen, Giao; Kim, Sangroh; Anderson-Evans, Colin; Johnson, G. Allan; Yoshizumi, Terry T.

2008-01-01

Digital subtraction angiography (DSA) X-ray imaging for small animals can be used for functional phenotyping given its ability to capture rapid physiological changes at high spatial and temporal resolution. The higher temporal and spatial requirements for small-animal imaging drive the need for short, high-flux X-ray pulses. However, high doses of ionizing radiation can affect the physiology. The purpose of this study was to verify and apply metal oxide semiconductor field effect transistor (MOSFET) technology to dosimetry for small-animal diagnostic imaging. A tungsten anode X-ray source was used to expose a tissue-equivalent mouse phantom. Dose measurements were made on the phantom surface and interior. The MOSFETs were verified with thermoluminescence dosimeters (TLDs). Bland-Altman analysis showed that the MOSFET results agreed with the TLD results (bias, 0.0625). Using typical small animal DSA scan parameters, the dose ranged from 0.7 to 2.2 cGy. Application of the MOSFETs in the small animal environment provided two main benefits: (1) the availability of results in near real-time instead of the hours needed for TLD processes and (2) the ability to support multiple exposures with different X-ray techniques (various of kVp, mA and ms) using the same MOSFET. This MOSFET technology has proven to be a fast, reliable small animal dosimetry method for DSA imaging and is a good system for dose monitoring for serial and gene expression studies. PMID:18666818

Air-stable and freestanding lithium alloy/graphene foil as an alternative to lithium metal anodes

NASA Astrophysics Data System (ADS)

Zhao, Jie; Zhou, Guangmin; Yan, Kai; Xie, Jin; Li, Yuzhang; Liao, Lei; Jin, Yang; Liu, Kai; Hsu, Po-Chun; Wang, Jiangyan; Cheng, Hui-Ming; Cui, Yi

2017-10-01

Developing high-capacity anodes is a must to improve the energy density of lithium batteries for electric vehicle applications. Alloy anodes are one promising option, but without pre-stored lithium, the overall energy density is limited by the low-capacity lithium metal oxide cathodes. Recently, lithium metal has been revived as a high-capacity anode, but faces several challenges owing to its high reactivity and uncontrolled dendrite growth. Here, we show a series of Li-containing foils inheriting the desirable properties of alloy anodes and pure metal anodes. They consist of densely packed LixM (M = Si, Sn, or Al) nanoparticles encapsulated by large graphene sheets. With the protection of graphene sheets, the large and freestanding LixM/graphene foils are stable in different air conditions. With fully expanded LixSi confined in the highly conductive and chemically stable graphene matrix, this LixSi/graphene foil maintains a stable structure and cyclability in half cells (400 cycles with 98% capacity retention). This foil is also paired with high-capacity Li-free V2O5 and sulfur cathodes to achieve stable full-cell cycling.

Air-stable and freestanding lithium alloy/graphene foil as an alternative to lithium metal anodes

DOE PAGES

Zhao, Jie; Zhou, Guangmin; Yan, Kai; ...

2017-07-10

Developing high-capacity anodes is a must to improve the energy density of lithium batteries for electric vehicle applications. Alloy anodes are one promising option, but without pre-stored lithium, the overall energy density is limited by the low-capacity lithium metal oxide cathodes. Recently, lithium metal has been revived as a high-capacity anode, but faces several challenges owing to its high reactivity and uncontrolled dendrite growth. Here, we show a series of Li-containing foils inheriting the desirable properties of alloy anodes and pure metal anodes. They consist of densely packed Li xM (M = Si, Sn, or Al) nanoparticles encapsulated by largemore » graphene sheets. With the protection of graphene sheets, the large and freestanding Li xM/graphene foils are stable in different air conditions. With fully expanded Li xSi confined in the highly conductive and chemically stable graphene matrix, this LixSi/graphene foil maintains a stable structure and cyclability in half cells (400 cycles with 98% capacity retention). As a result, this foil is also paired with high-capacity Li-free V 2O 5 and sulfur cathodes to achieve stable full-cell cycling.« less

Air-stable and freestanding lithium alloy/graphene foil as an alternative to lithium metal anodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Jie; Zhou, Guangmin; Yan, Kai

Developing high-capacity anodes is a must to improve the energy density of lithium batteries for electric vehicle applications. Alloy anodes are one promising option, but without pre-stored lithium, the overall energy density is limited by the low-capacity lithium metal oxide cathodes. Recently, lithium metal has been revived as a high-capacity anode, but faces several challenges owing to its high reactivity and uncontrolled dendrite growth. Here, we show a series of Li-containing foils inheriting the desirable properties of alloy anodes and pure metal anodes. They consist of densely packed Li xM (M = Si, Sn, or Al) nanoparticles encapsulated by largemore » graphene sheets. With the protection of graphene sheets, the large and freestanding Li xM/graphene foils are stable in different air conditions. With fully expanded Li xSi confined in the highly conductive and chemically stable graphene matrix, this LixSi/graphene foil maintains a stable structure and cyclability in half cells (400 cycles with 98% capacity retention). As a result, this foil is also paired with high-capacity Li-free V 2O 5 and sulfur cathodes to achieve stable full-cell cycling.« less

Characterization of d-succinylase from Cupriavidus sp. P4-10-C and its application in d-amino acid synthesis.

PubMed

Sumida, Yosuke; Iwai, Sachio; Nishiya, Yoshiaki; Kumagai, Shinya; Yamada, Toshihide; Azuma, Masayuki

2018-03-01

d-Amino acids are important building blocks for various compounds, such as pharmaceuticals and agrochemicals. A more cost-effective enzymatic method for d-amino acid production is needed in the industry. We improved a one-pot enzymatic method for d-amino acid production by the dynamic kinetic resolution of N-succinyl amino acids using two enzymes: d-succinylase (DSA) from Cupriavidus sp. P4-10-C, which hydrolyzes N-succinyl-d-amino acids enantioselectively to their corresponding d-amino acid, and N-succinyl amino acid racemase (NSAR, EC.4.2.1.113) from Geobacillus stearothermophilus NCA1503. In this study, DSA and NSAR were purified and their properties were investigated. The optimum temperature of DSA was 50°C and it was stable up to 55°C. The optimum pH of DSA and NSAR was around 7.5. In d-phenylalanine production, the optical purity of product was improved to 91.6% ee from the examination about enzyme concentration. Moreover, 100 mM N-succinyl-dl-tryptophan was converted to d-tryptophan at 81.8% yield with 94.7% ee. This enzymatic method could be useful for the industrial production of various d-amino acids. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Anodized aluminum on LDEF

NASA Technical Reports Server (NTRS)

Golden, Johnny L.

1993-01-01

A compilation of reported analyses and results obtained for anodized aluminum flown on the Long Duration Exposure Facility (LDEF) was prepared. Chromic acid, sulfuric acid, and dyed sulfuric acid anodized surfaces were exposed to the space environment. The vast majority of the anodized surface on LDEF was chromic acid anodize because of its selection as a thermal control coating for use on the spacecraft primary structure, trays, tray clamps, and space end thermal covers. Reports indicate that the chromic acid anodize was stable in solar absorptance and thermal emittance, but that contamination effects caused increases in absorptance on surfaces exposed to low atomic oxygen fluences. There were some discrepancies, however, in that some chromic acid anodized specimens exhibited significant increases in absorptance. Sulfuric acid anodized surfaces also appeared stable, although very little surface area was available for evaluation. One type of dyed sulfuric acid anodize was assessed as an optical baffle coating and was observed to have improved infrared absorptance characteristics with exposure on LDEF.

Oxygen-producing inert anodes for SOM process

DOEpatents

Pal, Uday B

2014-02-25

An electrolysis system for generating a metal and molecular oxygen includes a container for receiving a metal oxide containing a metallic species to be extracted, a cathode positioned to contact a metal oxide housed within the container; an oxygen-ion-conducting membrane positioned to contact a metal oxide housed within the container; an anode in contact with the oxygen-ion-conducting membrane and spaced apart from a metal oxide housed within the container, said anode selected from the group consisting of liquid metal silver, oxygen stable electronic oxides, oxygen stable crucible cermets, and stabilized zirconia composites with oxygen stable electronic oxides.

Design principles for electrolytes and interfaces for stable lithium-metal batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tikekar, Mukul D.; Choudhury, Snehashis; Tu, Zhengyuan

2016-09-08

The future of electrochemical energy storage hinges on the advancement of science and technology that enables rechargeable batteries that utilize reactive metals as anodes. With specific capacity more than ten times that of the LiC6 anode used in present-day lithium-ion batteries, cells based on Li-metal anodes are of particular interest. Effective strategies for stabilizing the anode in such cells are now understood to be a requirement for progress on exceptional storage technologies, including Li–S and Li–O2 batteries. Multiple challenges—parasitic reactions of Li-metal with liquid electrolytes, unstable and dendritic electrodeposition, and dendrite-induced short circuits—derailed early efforts to commercialize such lithium-metal batteries.more » Here we consider approaches for rationally designing electrolytes and Li-metal/electrolyte interfaces for stable, dendrite-free operation of lithium-metal batteries. On the basis of fundamental understanding of the failure modes of reactive metal anodes, we discuss the key variables that govern the stability of electrodeposition at the Li anode and propose a universal framework for designing stable electrolytes and interfaces for lithium-metal batteries.« less

Fast ion transport at solid-solid interfaces in hybrid battery anodes

NASA Astrophysics Data System (ADS)

Tu, Zhengyuan; Choudhury, Snehashis; Zachman, Michael J.; Wei, Shuya; Zhang, Kaihang; Kourkoutis, Lena F.; Archer, Lynden A.

2018-04-01

Carefully designed solid-electrolyte interphases are required for stable, reversible and efficient electrochemical energy storage in batteries. We report that hybrid battery anodes created by depositing an electrochemically active metal (for example, Sn, In or Si) on a reactive alkali metal electrode by a facile ion-exchange chemistry lead to very high exchange currents and stable long-term performance of electrochemical cells based on Li and Na electrodes. By means of direct visualization and ex situ electrodeposition studies, Sn-Li anodes are shown to be stable at 3 mA cm-2 and 3 mAh cm-2. Prototype full cells in which the hybrid anodes are paired with high-loading LiNi0.8Co0.15Al0.05O2(NCA) cathodes are also reported. As a second demonstration, we create and study Sn-Na hybrid anodes and show that they can be cycled stably for more than 1,700 hours with minimal voltage divergence. Charge storage at the hybrid anodes is reported to involve a combination of alloying and electrodeposition reactions.

Design principles for electrolytes and interfaces for stable lithium-metal batteries

NASA Astrophysics Data System (ADS)

Tikekar, Mukul D.; Choudhury, Snehashis; Tu, Zhengyuan; Archer, Lynden A.

2016-09-01

The future of electrochemical energy storage hinges on the advancement of science and technology that enables rechargeable batteries that utilize reactive metals as anodes. With specific capacity more than ten times that of the LiC6 anode used in present-day lithium-ion batteries, cells based on Li-metal anodes are of particular interest. Effective strategies for stabilizing the anode in such cells are now understood to be a requirement for progress on exceptional storage technologies, including Li-S and Li-O2 batteries. Multiple challenges—parasitic reactions of Li-metal with liquid electrolytes, unstable and dendritic electrodeposition, and dendrite-induced short circuits—derailed early efforts to commercialize such lithium-metal batteries. Here we consider approaches for rationally designing electrolytes and Li-metal/electrolyte interfaces for stable, dendrite-free operation of lithium-metal batteries. On the basis of fundamental understanding of the failure modes of reactive metal anodes, we discuss the key variables that govern the stability of electrodeposition at the Li anode and propose a universal framework for designing stable electrolytes and interfaces for lithium-metal batteries.

Performance comparison of tin oxide anodes to commercially available dimensionally stable anodes.

PubMed

Watts, Richard J; Finn, Dennis D; Wyeth, Megan S; Teel, Amy L

2008-06-01

Dimensionally stable anodes (DSAs) demonstrate potential for the electrochemical treatment of industrial waste streams and disinfection of effluent. Oxidation by laboratory-prepared tin oxide DSAs was compared with that of commercially available ruthenium oxide, iridium oxide, and mixed metal oxide DSAs, using hexanol as a probe molecule. The performance of the four anodes was similar in two-chamber reactors, in which the anode cell was separated from the cathode cell by a Nafion membrane, which allows transmission of current between the chambers, but not passage of chemical constituents. The anodes were then evaluated in single-cell reactors, which are more representative of potential treatment and disinfection applications. However, in the single-cell reactors, the tin oxide anodes were significantly more effective at oxidation and generated higher quality cyclic voltammograms than the other DSAs. These results suggest that tin oxide anodes have greater potential than the three commercially available DSAs tested for industrial waste stream treatment and effluent disinfection.

Phenol Contaminated Water Treatment on Several Modified Dimensionally Stable Anodes.

PubMed

Jayathilaka, Pavithra Bhakthi; Hapuhinna, Kushani Umanga Kumari; Bandara, Athula; Nanayakkara, Nadeeshani; Subasinghe, Nalaka Deepal

2017-08-01

  Phenolic compounds are some of the most common hazardous organics in wastewater. Removal of these pollutants is important. Physiochemical method such as electrochemical oxidation on dimensionally stable anodes is more convenient in removing such organic pollutants. Therefore, this study focuses on development of three different anodes for phenol contaminated water treatment. The performances of steel/IrO2, steel/IrO2-Sb2O3, and Ti/IrO2-Sb2O3 anodes were tested and compared. Nearly 50, 76, and 84% of chemical oxygen demand removal efficiencies were observed for steel/IrO2, steel/IrO2-Sb2O3, and Ti/IrO2-Sb2O3 anodes, respectively. The formation of intermediates was monitored for three anodes and the Ti/IrO2-Sb2O3 anode showed the most promising results. Findings suggest that the developed anode materials can enhance phenol oxidation efficiency and that mixed metal oxide layer has major influence on the anode. Among the selected metal oxide mixtures IrO2-Sb2O3 was the most suitable under given experimental conditions.

DSA process window expansion with novel DSA track hardware

NASA Astrophysics Data System (ADS)

Harumoto, Masahiko; Stokes, Harold; Tanaka, Yuji; Kaneyama, Koji; Pieczulewski, Chalres; Asai, Masaya; Argoud, Maxime; Servin, Isabelle; Chamiot-Maitral, Gaëlle; Claveau, Guillaume; Tiron, Raluca; Cayrefourcq, Ian

2017-03-01

PS-b-PMMA block copolymer is a well-known DSA material, and there are many DSA patterning methods that make effective the use of such 1st generation materials. Consequently, this variety of patterning methods opens a wide array of possibilities for DSA application[1-4]. Last year, during the inaugural International DSA Symposium, researchers and lithographers concurred on common key issues for DSA patterning methods such as: defect density, LWR, placement error, etc. Defect density was specifically expressed as the biggest obstacle for new processes. Coat-Develop track systems contribute to the DSA pattern fabrication and also influence the DSA pattern performances[4]. In this study, defectivity was investigated using an atmosphere-controlled chamber on the SOKUDO DUO track. As an initial step for expanding the DSA process window, fingerprint patterns were used for various atmospheric conditions during DSA self-assembly annealing. In this study, we will demonstrate an improved DSA process window, and then we will discuss the mechanism for this atmospheric effect.

Intermediate-term graft loss after renal transplantation is associated with both donor-specific antibody and acute rejection.

PubMed

Devos, Jennifer M; Gaber, Ahmed Osama; Teeter, Larry D; Graviss, Edward A; Patel, Samir J; Land, Geoffrey A; Moore, Linda W; Knight, Richard J

2014-03-15

Renal transplant recipients with de novo DSA (dDSA) experience higher rates of rejection and worse graft survival than dDSA-free recipients. This study presents a single-center review of dDSA monitoring in a large, multi-ethnic cohort of renal transplant recipients. The authors performed a nested case-control study of adult kidney and kidney-pancreas recipients from July 2007 through July 2011. Cases were defined as dDSA-positive whereas controls were all DSA-negative transplant recipients. DSA were determined at 1, 3, 6, 9, and 12 months posttransplant, and every 6 months thereafter. Of 503 recipients in the analysis, 24% developed a dDSA, of whom 73% had dDSA against DQ antigen. Median time to dDSA was 6.1 months (range 0.2-44.6 months). After multivariate analysis, African American race, kidney-pancreas recipient, and increasing numbers of human leukocyte antigen mismatches were independent risk factors for dDSA. Recipients with dDSA were more likely to suffer an acute rejection (AR) (35% vs. 10%, P<0.001), an antibody-mediated AR (16% vs. 0.3%, P<0.001), an AR ascribed to noncompliance (8% vs. 2%, P=0.001), and a recurrent AR (6% vs. 1%, P=0.002) than dDSA-negative recipients. At a median follow-up of 31 months, the death-censored actuarial graft survival of dDSA recipients was worse than the DSA-free cohort (P=0.002). Yet, for AR-free recipients, there was no difference in graft survival between cohorts (P=0.66). Development of dDSA was associated with an increased incidence of graft loss, yet the detrimental effect of dDSA was limited in the intermediate term to recipients with AR.

De Novo DQ Donor-Specific Antibodies Are Associated with Chronic Lung Allograft Dysfunction after Lung Transplantation.

PubMed

Tikkanen, Jussi M; Singer, Lianne G; Kim, S Joseph; Li, Yanhong; Binnie, Matthew; Chaparro, Cecilia; Chow, Chung-Wai; Martinu, Tereza; Azad, Sassan; Keshavjee, Shaf; Tinckam, Kathryn

2016-09-01

Despite increasing evidence about the role of donor-specific human leukocyte antigen (HLA) antibodies in transplant outcomes, the incidence and impact of de novo donor-specific antibodies (dnDSA) after lung transplantation remains unclear. To describe the incidence, characteristics, and impact of dnDSA after lung transplantation. We investigated a single-center cohort of 340 lung transplant recipients undergoing transplant during 2008 to 2011. All patients underwent HLA-antibody testing quarterly pretransplant and at regular intervals over the first 24 months after transplant. The patients received modified immunosuppression depending on their pretransplant sensitization status. Risk factors for dnDSA development, as well as the associations of dnDSA with patient survival and chronic lung allograft dysfunction (CLAD), were determined using multivariable analysis. The cumulative incidence of dnDSA was 47% at a median of 86 days (range, 44-185 d) after lung transplantation. Seventy-six percent of recipients with dnDSA had DQ-DSA. Male sex and the use of ex vivo lung perfusion were associated with an increased risk of dnDSA, whereas increased HLA-DQB1 matching was protective. DQ-dnDSA preceded or coincided with the diagnosis of CLAD in all cases. Developing dnDSA (vs. no dnDSA) was associated with a twofold increased risk of CLAD (hazard ratio, 2.04; 95% confidence interval, 1.13-3.69). This association appeared to be driven by the development of DQ-dnDSA. dnDSA are common after lung transplantation, with the majority being DQ DSA. DQ-dnDSA are associated with an increased risk of CLAD. Strategies to prevent or treat DQ-dnDSA may improve outcomes for lung transplant recipients.

N7 logic via patterning using templated DSA: implementation aspects

NASA Astrophysics Data System (ADS)

Bekaert, J.; Doise, J.; Gronheid, R.; Ryckaert, J.; Vandenberghe, G.; Fenger, G.; Her, Y. J.; Cao, Y.

2015-07-01

In recent years, major advancements have been made in the directed self-assembly (DSA) of block copolymers (BCP). Insertion of DSA for IC fabrication is seriously considered for the 7 nm node. At this node the DSA technology could alleviate costs for multiple patterning and limit the number of masks that would be required per layer. At imec, multiple approaches for inserting DSA into the 7 nm node are considered. One of the most straightforward approaches for implementation would be for via patterning through templated DSA; a grapho-epitaxy flow using cylindrical phase BCP material resulting in contact hole multiplication within a litho-defined pre-pattern. To be implemented for 7 nm node via patterning, not only the appropriate process flow needs to be available, but also DSA-aware mask decomposition is required. In this paper, several aspects of the imec approach for implementing templated DSA will be discussed, including experimental demonstration of density effect mitigation, DSA hole pattern transfer and double DSA patterning, creation of a compact DSA model. Using an actual 7 nm node logic layout, we derive DSA-friendly design rules in a logical way from a lithographer's view point. A concrete assessment is provided on how DSA-friendly design could potentially reduce the number of Via masks for a place-and-routed N7 logic pattern.

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

PubMed Central

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

2009-01-01

A thin layer electrochemical cell was tested and developed for disinfection treatment of water artificially contaminated with Staphylococcus aureus. Electrolysis was performed with a low-voltage DC power source applying current densities of 75 mA cm-2 (3 A) or 25 mA cm-2 (1 A). A dimensionally stable anode (DSA) of titanium coated with an oxide layer of 70%TiO2 plus 30%RuO2 (w/w) and a 3 mm from a stainless-steel 304 cathode was used in the thin layer cell. The experiments were carried out using a bacteria suspension containing 0.08 M sodium sulphate with chloride-free to determine the bacterial inactivation efficacy of the thin layer cell without the generation of chlorine. The chlorine can promote the formation of trihalomethanes (THM) that are carcinogenic. S. aureus inactivation increased with electrolysis time and lower flow rate. The flow rates used were 200 or 500 L h-1. At 500 L h-1 and 75 mA cm-2 the inactivation after 60 min was about three logs of decreasing for colony forming units by mL. However, 100% inactivation for S. aureus was observed at 5.6 V and 75 mA cm-2 after 30 min. Thus, significant disinfection levels can be achieved without adding oxidant substances or generation of chlorine in the water. PMID:24031410

Electrodegradation of the Acid Green 28 dye using Ti/β-PbO2 and Ti-Pt/β-PbO2 anodes.

PubMed

Irikura, Kallyni; Bocchi, Nerilso; Rocha-Filho, Romeu C; Biaggio, Sonia R; Iniesta, Jesús; Montiel, Vicente

2016-12-01

The statistical Response Surface Methodology (RSM) is applied to investigate the effect of different parameters (current density, j, NaCl concentration, [NaCl], pH, and temperature, θ) and their interactions on the electrochemical degradation of the Acid Green (AG) 28 dye using a Ti/β-PbO2 or Ti-Pt/β-PbO2 anode in a filter-press reactor. LC/MS is employed to identify intermediate compounds. For both anodes, the best experimental conditions are j = 50 mA cm(-2), [NaCl] = 1.5 g L(-1), pH = 5, and θ = 25 °C. After 3 h of electrolysis, a dye solution treated under these conditions presents the following parameters: electric charge per unit volume of the electrolyzed solution required for 90% decolorization (Q(90)) of 0.34-0.37 A h L(-1), %COD removal of ∼100%, specific energy consumption of 18-20 kW h m(-3), and %TOC removal of 32-33%. No loss of the β-PbO2 film is observed during all the experiments. The β-PbO2 films present excellent stability for solutions with pH ≥ 5 ([Pb(2+)] < 0.5 mg L(-1)). Chloroform is the only volatile organic halo compound present in the treated solution under those optimized conditions. Hydroxylated anthraquinone derivatives, aromatic chloramines, and naphthoquinones are formed during the electrolyses. The Ti/β-PbO2 and Ti-Pt/β-PbO2 anodes show significantly better performance than a commercial DSA anode for the electrochemical degradation of the AG 28 dye. The Ti/β-PbO2 anode, prepared as described in this work, is an excellent option for the treatment of textile effluents because of its low cost of fabrication and good performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

A High-Performing Sulfur-Tolerant and Redox-Stable Layered Perovskite Anode for Direct Hydrocarbon Solid Oxide Fuel Cells

PubMed Central

Ding, Hanping; Tao, Zetian; Liu, Shun; Zhang, Jiujun

2015-01-01

Development of alternative ceramic oxide anode materials is a key step for direct hydrocarbon solid oxide fuel cells (SOFCs). Several lanthanide based layered perovskite-structured oxides demonstrate outstanding oxygen diffusion rate, favorable electronic conductivity, and good oxygen surface exchange kinetics, owing to A-site ordered structure in which lanthanide and alkali-earth ions occupy alternate (001) layers and oxygen vacancies are mainly located in [LnOx] planes. Here we report a nickel-free cation deficient layered perovskite, (PrBa)0.95(Fe0.9Mo0.1)2O5 + δ (PBFM), for SOFC anode, and this anode shows an outstanding performance with high resistance against both carbon build-up and sulfur poisoning in hydrocarbon fuels. At 800 °C, the layered PBFM showed high electrical conductivity of 59.2 S cm−1 in 5% H2 and peak power densities of 1.72 and 0.54 W cm−2 using H2 and CH4 as fuel, respectively. The cell exhibits a very stable performance under a constant current load of 1.0 A cm−2. To our best knowledge, this is the highest performance of ceramic anodes operated in methane. In addition, the anode is structurally stable at various fuel and temperature conditions, suggesting that it is a feasible material candidate for high-performing SOFC anode. PMID:26648509

A High-Performing Sulfur-Tolerant and Redox-Stable Layered Perovskite Anode for Direct Hydrocarbon Solid Oxide Fuel Cells

NASA Astrophysics Data System (ADS)

Ding, Hanping; Tao, Zetian; Liu, Shun; Zhang, Jiujun

2015-12-01

Development of alternative ceramic oxide anode materials is a key step for direct hydrocarbon solid oxide fuel cells (SOFCs). Several lanthanide based layered perovskite-structured oxides demonstrate outstanding oxygen diffusion rate, favorable electronic conductivity, and good oxygen surface exchange kinetics, owing to A-site ordered structure in which lanthanide and alkali-earth ions occupy alternate (001) layers and oxygen vacancies are mainly located in [LnOx] planes. Here we report a nickel-free cation deficient layered perovskite, (PrBa)0.95(Fe0.9Mo0.1)2O5 + δ (PBFM), for SOFC anode, and this anode shows an outstanding performance with high resistance against both carbon build-up and sulfur poisoning in hydrocarbon fuels. At 800 °C, the layered PBFM showed high electrical conductivity of 59.2 S cm-1 in 5% H2 and peak power densities of 1.72 and 0.54 W cm-2 using H2 and CH4 as fuel, respectively. The cell exhibits a very stable performance under a constant current load of 1.0 A cm-2. To our best knowledge, this is the highest performance of ceramic anodes operated in methane. In addition, the anode is structurally stable at various fuel and temperature conditions, suggesting that it is a feasible material candidate for high-performing SOFC anode.

A High-Performing Sulfur-Tolerant and Redox-Stable Layered Perovskite Anode for Direct Hydrocarbon Solid Oxide Fuel Cells.

PubMed

Ding, Hanping; Tao, Zetian; Liu, Shun; Zhang, Jiujun

2015-12-09

Development of alternative ceramic oxide anode materials is a key step for direct hydrocarbon solid oxide fuel cells (SOFCs). Several lanthanide based layered perovskite-structured oxides demonstrate outstanding oxygen diffusion rate, favorable electronic conductivity, and good oxygen surface exchange kinetics, owing to A-site ordered structure in which lanthanide and alkali-earth ions occupy alternate (001) layers and oxygen vacancies are mainly located in [LnOx] planes. Here we report a nickel-free cation deficient layered perovskite, (PrBa)0.95(Fe0.9Mo0.1)2O5 + δ (PBFM), for SOFC anode, and this anode shows an outstanding performance with high resistance against both carbon build-up and sulfur poisoning in hydrocarbon fuels. At 800 °C, the layered PBFM showed high electrical conductivity of 59.2 S cm(-1) in 5% H2 and peak power densities of 1.72 and 0.54 W cm(-2) using H2 and CH4 as fuel, respectively. The cell exhibits a very stable performance under a constant current load of 1.0 A cm(-2). To our best knowledge, this is the highest performance of ceramic anodes operated in methane. In addition, the anode is structurally stable at various fuel and temperature conditions, suggesting that it is a feasible material candidate for high-performing SOFC anode.

Zbtb7a induction in alveolar macrophages is implicated in anti-HLA-mediated lung allograft rejection.

PubMed

Nayak, Deepak K; Zhou, Fangyu; Xu, Min; Huang, Jing; Tsuji, Moriya; Yu, Jinsheng; Hachem, Ramsey; Gelman, Andrew E; Bremner, Ross M; Smith, Michael A; Mohanakumar, Thalachallour

2017-07-12

Chronic rejection significantly limits long-term success of solid organ transplantation. De novo donor-specific antibodies (DSAs) to mismatched donor human leukocyte antigen after human lung transplantation predispose lung grafts to chronic rejection. We sought to delineate mediators and mechanisms of DSA pathogenesis and to define early inflammatory events that trigger chronic rejection in lung transplant recipients and obliterative airway disease, a correlate of human chronic rejection, in mouse. Induction of transcription factor zinc finger and BTB domain containing protein 7a (Zbtb7a) was an early response critical in the DSA-induced chronic rejection. A cohort of human lung transplant recipients who developed DSA and chronic rejection demonstrated greater Zbtb7a expression long before clinical diagnosis of chronic rejection compared to nonrejecting lung transplant recipients with stable pulmonary function. Expression of DSA-induced Zbtb7a was restricted to alveolar macrophages (AMs), and selective disruption of Zbtb7a in AMs resulted in less bronchiolar occlusion, low immune responses to lung-restricted self-antigens, and high protection from chronic rejection in mice. Additionally, in an allogeneic cell transfer protocol, antigen presentation by AMs was Zbtb7a-dependent where AMs deficient in Zbtb7a failed to induce antibody and T cell responses. Collectively, we demonstrate that AMs play an essential role in antibody-induced pathogenesis of chronic rejection by regulating early inflammation and lung-restricted humoral and cellular autoimmunity. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Incidence and Factors Associated with De Novo DSA After BK Viremia in Renal Transplant Recipients.

PubMed

Patel, Samir J; Kuten, Samantha A; Knight, Richard J; Graviss, Edward A; Nguyen, Duc; Gaber, A Osama

2016-01-01

BK polyomavirus infection and de novo donor-human leukocyte antigen (HLA) specific antibodies (dnDSA) are two well-known and distinct complications occurring after kidney transplantation. Recent literature suggests an association between the two events. This study aims to examine the relationship between BK viremia (BKV) and dnDSA and to identify potential risk factors for dnDSA following BKV in kidney transplant recipients. A retrospective review of 1019 recipients from Houston Methodist Hospital was conducted. All patients underwent routine screening for BKV and dnDSA. Median follow-up was 44 months. BKV was detected in 186 (18%) patients at a median of 107 (82-205) days post-transplant. dnDSA occurred in 283 (28%) patients at a median of 272 (62-575) days post-transplant. Of the 69 dnDSA-positive/BKV-positive patients, dnDSA detection occurred after BKV onset in 46 patients. Thus, 46 (28%) previously DSA-negative patients later became dnDSA-positive following BKV, not significantly different from the rate seen in BKV-negative patients (26%; p=0.5). Median time to DSA detection following BKV onset was 232 days (interquartile range, 119-460) post-BKV detection. Multivariate analysis revealed a greater number of HLA mismatches and viral clearance as risk factors for development of dnDSA following BKV, whereas delayed graft function was associated with a lower risk of dnDSA. In conclusion, despite being considered a result of over-immunosuppression, BKV can still be followed by dnDSA in a substantial proportion of patients. Monitoring for dnDSA in patients being managed for BKV may be warranted. Copyright© 2017 by the Terasaki Research Institute.

Successful Renal Transplantation with Desensitization in Highly Sensitized Patients: A Single Center Experience

PubMed Central

Yoon, Hye Eun; Hyoung, Bok Jin; Hwang, Hyeon Seok; Lee, So Young; Jeon, Youn Joo; Song, Joon Chang; Oh, Eun-Jee; Park, Sun Cheol; Choi, Bum Soon; Moon, In Sung; Kim, Yong Soo

2009-01-01

Intravenous immunoglobulin (IVIG) and/or plasmapheresis (PP) are effective in preventing antibody-mediated rejection (AMR) of kidney allografts, but AMR is still a problem. This study reports our experience in living donor renal transplantation in highly sensitized patients. Ten patients with positive crossmatch tests or high levels of panel-reactive antibody (PRA) were included. Eight patients were desensitized with pretransplant PP and low dose IVIG, and two were additionally treated with rituximab. Allograft function, number of acute rejection (AR) episodes, protocol biopsy findings, and the presence of donor-specific antibody (DSA) were evaluated. With PP/IVIG, six out of eight patients showed good graft function without AR episodes. Protocol biopsies revealed no evidence of tissue injury or C4d deposits. Of two patients with AR, one was successfully treated with PP/IVIG, but the other lost graft function due to de novo production of DSA. Thereafter, rituximab was added to PP/IVIG in two cases. Rituximab gradually decreased PRA levels and the percentage of peripheral CD20+ cells. DSA was undetectable and protocol biopsy showed no C4d deposits. The graft function was stable and there were no AR episodes. Conclusively, desensitization using PP/IVIG with or without rituximab increases the likelihood of successful living donor renal transplantation in sensitized recipients. PMID:19194545

Silicon algae with carbon topping as thin-film anodes for lithium-ion microbatteries by a two-step facile method

NASA Astrophysics Data System (ADS)

Biserni, E.; Xie, M.; Brescia, R.; Scarpellini, A.; Hashempour, M.; Movahed, P.; George, S. M.; Bestetti, M.; Li Bassi, A.; Bruno, P.

2015-01-01

Silicon-based electrodes for Li-ion batteries (LIB) attract much attention because of their high theoretical capacity. However, their large volume change during lithiation results in poor cycling due to mechanical cracking. Moreover, silicon can hardly form a stable solid electrolyte interphase (SEI) layer with common electrolytes. We present a safe, innovative strategy to prepare nanostructured silicon-carbon anodes in a two-step process. The nanoporosity of Si films accommodates the volume expansion while a disordered graphitic C layer on top promotes the formation of a stable SEI. This approach shows its promises: carbon-coated porous silicon anodes perform in a very stable way, reaching the areal capacity of ∼175 μAh cm-2, and showing no decay for at least 1000 cycles. With requiring only a two-step deposition process at moderate temperatures, this novel very simple cell concept introduces a promising way to possibly viable up-scaled production of next-generation nanostructured Si anodes for lithium-ion microbatteries.

IgG Donor-Specific Anti-Human HLA Antibody Subclasses and Kidney Allograft Antibody-Mediated Injury.

PubMed

Lefaucheur, Carmen; Viglietti, Denis; Bentlejewski, Carol; Duong van Huyen, Jean-Paul; Vernerey, Dewi; Aubert, Olivier; Verine, Jérôme; Jouven, Xavier; Legendre, Christophe; Glotz, Denis; Loupy, Alexandre; Zeevi, Adriana

2016-01-01

Antibodies may have different pathogenicities according to IgG subclass. We investigated the association between IgG subclasses of circulating anti-human HLA antibodies and antibody-mediated kidney allograft injury. Among 635 consecutive kidney transplantations performed between 2008 and 2010, we enrolled 125 patients with donor-specific anti-human HLA antibodies (DSA) detected in the first year post-transplant. We assessed DSA characteristics, including specificity, HLA class specificity, mean fluorescence intensity (MFI), C1q-binding, and IgG subclass, and graft injury phenotype at the time of sera evaluation. Overall, 51 (40.8%) patients had acute antibody-mediated rejection (aABMR), 36 (28.8%) patients had subclinical ABMR (sABMR), and 38 (30.4%) patients were ABMR-free. The MFI of the immunodominant DSA (iDSA, the DSA with the highest MFI level) was 6724±464, and 41.6% of patients had iDSA showing C1q positivity. The distribution of iDSA IgG1-4 subclasses among the population was 75.2%, 44.0%, 28.0%, and 26.4%, respectively. An unsupervised principal component analysis integrating iDSA IgG subclasses revealed aABMR was mainly driven by IgG3 iDSA, whereas sABMR was driven by IgG4 iDSA. IgG3 iDSA was associated with a shorter time to rejection (P<0.001), increased microcirculation injury (P=0.002), and C4d capillary deposition (P<0.001). IgG4 iDSA was associated with later allograft injury with increased allograft glomerulopathy and interstitial fibrosis/tubular atrophy lesions (P<0.001 for all comparisons). Integrating iDSA HLA class specificity, MFI level, C1q-binding status, and IgG subclasses in a Cox survival model revealed IgG3 iDSA and C1q-binding iDSA were strongly and independently associated with allograft failure. These results suggest IgG iDSA subclasses identify distinct phenotypes of kidney allograft antibody-mediated injury. Copyright © 2016 by the American Society of Nephrology.

DSA patterning options for logics and memory applications

NASA Astrophysics Data System (ADS)

Liu, Chi-Chun; Franke, Elliott; Mignot, Yann; LeFevre, Scott; Sieg, Stuart; Chi, Cheng; Meli, Luciana; Parnell, Doni; Schmidt, Kristin; Sanchez, Martha; Singh, Lovejeet; Furukawa, Tsuyoshi; Seshadri, Indira; De Silva, Ekmini Anuja; Tsai, Hsinyu; Lai, Kafai; Truong, Hoa; Farrell, Richard; Bruce, Robert; Somervell, Mark; Sanders, Daniel; Felix, Nelson; Arnold, John; Hetzer, David; Ko, Akiteru; Metz, Andrew; Colburn, Matthew; Corliss, Daniel

2017-03-01

The progress of three potential DSA applications, i.e. fin formation, via shrink, and pillars, were reviewed in this paper. For fin application, in addition to pattern quality, other important considerations such as customization and design flexibility were discussed. An electrical viachain study verified the DSA rectification effect on CD distribution by showing a tighter current distribution compared to that derived from the guiding pattern direct transfer without using DSA. Finally, a structural demonstration of pillar formation highlights the importance of pattern transfer in retaining both the CD and local CDU improvement from DSA. The learning from these three case studies can provide perspectives that may not have been considered thoroughly in the past. By including more important elements during DSA process development, the DSA maturity can be further advanced and move DSA closer to HVM adoption.

Design strategy for integrating DSA via patterning in sub-7 nm interconnects

NASA Astrophysics Data System (ADS)

Karageorgos, Ioannis; Ryckaert, Julien; Tung, Maryann C.; Wong, H.-S. P.; Gronheid, Roel; Bekaert, Joost; Karageorgos, Evangelos; Croes, Kris; Vandenberghe, Geert; Stucchi, Michele; Dehaene, Wim

2016-03-01

In recent years, major advancements have been made in the directed self-assembly (DSA) of block copolymers (BCPs). As a result, the insertion of DSA for IC fabrication is being actively considered for the sub-7nm nodes. At these nodes the DSA technology could alleviate costs for multiple patterning and limit the number of litho masks that would be required per metal layer. One of the most straightforward approaches for DSA implementation would be for via patterning through templated DSA, where hole patterns are readily accessible through templated confinement of cylindrical phase BCP materials. Our in-house studies show that decomposition of via layers in realistic circuits below the 7nm node would require at least many multi-patterning steps (or colors), using 193nm immersion lithography. Even the use of EUV might require double patterning in these dimensions, since the minimum via distance would be smaller than EUV resolution. The grouping of vias through templated DSA can resolve local conflicts in high density areas. This way, the number of required colors can be significantly reduced. For the implementation of this approach, a DSA-aware mask decomposition is required. In this paper, our design approach for DSA via patterning in sub-7nm nodes is discussed. We propose options to expand the list of DSA-compatible via patterns (DSA letters) and we define matching cost formulas for the optimal DSA-aware layout decomposition. The flowchart of our proposed approach tool is presented.

Influence of preformed donor-specific antibodies and C4d on early liver allograft function.

PubMed

Perera, M T; Silva, M A; Murphy, N; Briggs, D; Mirza, D F; Neil, D A H

2013-12-01

INTRODUCTION. The impact of preformed donor-specific antibodies (DSA) is incompletely understood in liver transplantation. The incidence and impact of preformed DSA on early post liver transplant were assessed and these were correlated with compliment fragment C4d on allograft biopsy. METHODS. Pretransplant serum from 41 consecutive liver transplant recipients (brain dead donors; DBD = 27 and cardiac death donors; DCD = 14) were tested for class-specific anti-human leukocyte antigen (HLA) and compared against donor HLA types. Liver biopsies were taken during cold storage (t-1) and post-reperfusion (t0) stained with C4d and graded for preservation-reperfusion injury (PRI). RESULTS. Of the 41 recipients, 8 (20%) had anti-HLA class I/II antibodies pretransplant, 3 (7%) were confirmed preformed DSA; classes I and II (n=1) and class I only (n=2). No biopsies showed definite evidence of antibody-mediated rejection. Graft biopsies in overall showed only mild PRI with ischemic hepatocyte C4d pattern similar in both positive and negative DSA patients. One DSA-positive (33%) compared with four DSA-negative patients (10%) had significant early graft dysfunction; severe PRI causing graft loss from primary nonfunction was seen only in DSA-negative group. Allograft biopsy of preformed DSA-positive patient demonstrated only minimal PRI; however, no identifiable cause could be attributed to graft dysfunction other than preformed DSA. CONCLUSION. Preformed DSA are present in 5-10% liver transplant recipients. There is no association between anti-HLA DSA and PRI and C4d, but preformed DSA may cause early morbidity. Larger studies on the impact of DSA with optimization of C4d techniques are required.

Pre-transplant soluble CD30 in combination with total DSA but not pre-transplant C1q-DSA predicts antibody-mediated graft loss in presensitized high-risk kidney transplant recipients.

PubMed

Schaefer, S M; Süsal, C; Opelz, G; Döhler, B; Becker, L E; Klein, K; Sickmüller, S; Waldherr, R; Macher-Goeppinger, S; Schemmer, P; Beimler, J; Zeier, M; Morath, C

2016-02-01

Presensitized kidney transplant recipients are at high-risk for early antibody-mediated rejection. We studied the impact of pre- and post-transplant donor-specific human leukocyte antigen (HLA) antibodies (DSA) and T-cell-activation on the occurrence of antibody-mediated rejection episodes (AMR) and graft loss (AMR-GL) in a unique cohort of 80 desensitized high-risk kidney transplant recipients. Patients with pre-transplant DSA demonstrated more AMR episodes than patients without DSA, but did not show a significantly increased rate of AMR-GL. The rates of AMR and AMR-GL were not significantly increased in patients with complement split product (C1q)-binding pre-transplant DSA. Pre-transplant C1q-DSA became undetectable post-transplant in 11 of 13 (85%) patients; 2 (18%) of these 11 patients showed AMR but no AMR-GL. In contrast, the post-transplant presence of C1q-DSA was associated with significantly higher rates of AMR (86 vs 33 vs 0%; P < 0.001) and AMR-GL (86 vs 0 vs 0%; log-rank P < 0.001) compared with post-transplant DSA without C1q-binding or the absence of DSA. Patients with both pre-transplant DSA and evidence of pre-transplant T-cell-activation as indicated by soluble CD30-positivity showed a significantly increased risk for AMR-GL [HR = 11.1, 95% confidence interval (CI) = 1.68-73.4; log-rank P = 0.013]. In these high-risk patients, AMR-GL was associated with total DSA in combination with T-cell-activation pre-transplant, and de novo or persistent C1q-binding DSA post-transplant. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Electrical study of DSA shrink process and CD rectification effect at sub-60nm using EUV test vehicle

NASA Astrophysics Data System (ADS)

Chi, Cheng; Liu, Chi-Chun; Meli, Luciana; Guo, Jing; Parnell, Doni; Mignot, Yann; Schmidt, Kristin; Sanchez, Martha; Farrell, Richard; Singh, Lovejeet; Furukawa, Tsuyoshi; Lai, Kafai; Xu, Yongan; Sanders, Daniel; Hetzer, David; Metz, Andrew; Burns, Sean; Felix, Nelson; Arnold, John; Corliss, Daniel

2017-03-01

In this study, the integrity and the benefits of the DSA shrink process were verified through a via-chain test structure, which was fabricated by either DSA or baseline litho/etch process for via layer formation while metal layer processes remain the same. The nearest distance between the vias in this test structure is below 60nm, therefore, the following process components were included: 1) lamella-forming BCP for forming self-aligned via (SAV), 2) EUV printed guiding pattern, and 3) PS-philic sidewall. The local CDU (LCDU) of minor axis was improved by 30% after DSA shrink process. We compared two DSA Via shrink processes and a DSA_Control process, in which guiding patterns (GP) were directly transferred to the bottom OPL without DSA shrink. The DSA_Control apparently resulted in larger CD, thus, showed much higher open current and shorted the dense via chains. The non-optimized DSA shrink process showed much broader current distribution than the improved DSA shrink process, which we attributed to distortion and dislocation of the vias and ineffective SAV. Furthermore, preliminary defectivity study of our latest DSA process showed that the primary defect mode is likely to be etch-related. The challenges, strategies applied to improve local CD uniformity and electrical current distribution, and potential adjustments were also discussed.

Conventional digital subtractional vs non-invasive MR angiography in the assessment of brain arteriovenous malformation.

PubMed

Cuong, Nguyen Ngoc; Luu, Vu Dang; Tuan, Tran Anh; Linh, Le Tuan; Hung, Kieu Dinh; Ngoc, Vo Truong Nhu; Sharma, Kulbhushan; Pham, Van Huy; Chu, Dinh-Toi

2018-06-01

Digital subtractional angiography (DSA) is the standard method for diagnosis, assessment and management of arteriovenous malformation in the brain. Conventional DSA (cDSA) is an invasive imaging modality that is often indicated before interventional treatments (embolization, open surgery, gamma knife). Here, we aimed to compare this technique with a non-invasive MR angiography (MRI DSA) for brain arteriovenous malformation (bAVM). Fourteen patients with ruptured brain AVM underwent embolization treatment pre-operation. Imaging was performed for all patients using MRI (1.5 T). After injecting contrast Gadolinium, dynamic MRI was performed with 40 phases, each phase of a duration of 1.2 s and having 70 images. The MRI results were independently assessed by experienced radiologist blinded to the cDSA. The AVM nidus was depicted in all patients using cDSA and MRI DSA; there was an excellent correlation between these techniques in terms of the maximum diameter and Spetzler Martin grading. Of the fourteen patients, the drainage vein was depicted in 13 by both cDSA and MRI DSA showing excellent correlation between the techniques used. MRI DSA is a non-invasive imaging modality that can give the images in dynamic view. It can be considered as an adjunctive method with cDSA to plan the strategy treatment for bAVM. Copyright © 2018 Elsevier B.V. All rights reserved.

The possible critical role of T-cell help in DSA-mediated graft loss.

PubMed

Süsal, Caner; Slavcev, Antonij; Pham, Lien; Zeier, Martin; Morath, Christian

2018-06-01

In this review, we discuss a possible central role of T-cell help in severe forms of graft damage mediated by donor-specific HLA antibodies (DSA). Some kidney transplant recipients with pretransplant DSA show a high graft failure rate, whereas in other patients DSA do not harm the transplanted kidney and in most cases, disappear shortly after transplantation. Analyzing 80 desensitized highly immunized kidney transplant recipients and another multicenter cohort of 385 patients with pretransplant HLA antibodies, we reported recently that an ongoing T-cell help from an activated immune system, as measured by an increased level of soluble CD30 in serum, might be necessary for the DSA to exert a deleterious effect. Patients positive for both pretransplant DSA and sCD30 appear to require special measures, such as the elimination of DSA from the circulation, potent immunosuppression, good HLA-matching, and intense post-transplant monitoring, whereas exclusion of DSA-positive patients from transplantation in the absence of high sCD30 may not be justified in all cases, even if the pretransplant DSA are strong and complement-activating. © 2018 Steunstichting ESOT.

Sulfur poisoning of Ni/Gadolinium-doped ceria anodes: A long-term study outlining stable solid oxide fuel cell operation

NASA Astrophysics Data System (ADS)

Riegraf, Matthias; Zekri, Atef; Knipper, Martin; Costa, Rémi; Schiller, Günter; Friedrich, K. Andreas

2018-03-01

This work presents an analysis of the long-term behavior of nickel/gadolinium-doped ceria (CGO) anode-based solid oxide fuel cells (SOFC) under sulfur poisoning conditions. A parameter study of sulfur-induced irreversible long-term degradation of commercial, high-performance single cells was carried out at 900 °C for different H2/N2/H2S fuel gas atmospheres, current densities and Ni/CGO anodes. The poisoning periods of the cells varied from 200 to 1500 h. The possibility of stable long-term Ni/CGO anode operation under sulfur exposure is established and the critical operating regime is outlined. Depending on the operating conditions, two degradation phenomena can be observed. Small degradation of the ohmic resistance was witnessed for sulfur exposure times of approximately 1000 h. Moreover, degradation of the anode charge transfer resistance was observed to be triggered by the combination of a small anodic potential step and high sulfur coverage on Ni. The microstructural evolution of altered Ni/CGO anodes was examined post-mortem by means of SEM and FIB/SEM, and is correlated to the anode performance degradation under critical operating conditions, establishing Ni depletion, porosity increase and a tripe phase boundary density decrease in the anode functional layer. It is shown that short-term sulfur poisoning behavior can be used to assess long-term stability.

Electrochemical advanced oxidation for cold incineration of the pharmaceutical ranitidine: mineralization pathway and toxicity evolution.

PubMed

Olvera-Vargas, Hugo; Oturan, Nihal; Brillas, Enric; Buisson, Didier; Esposito, Giovanni; Oturan, Mehmet A

2014-12-01

Ranitidine (RNTD) is a widely prescribed histamine H2-receptor antagonist whose unambiguous presence in water sources appointed it as an emerging pollutant. Here, the degradation of 0.1 mM of this drug in aqueous medium was studied by electrochemical advanced oxidation processes (EAOPs) like anodic oxidation with electrogenerated H2O2 and electro-Fenton using Pt/carbon-felt, BDD/carbon-felt and DSA-Ti/RuO2–IrO2/carbon-felt cells. The higher oxidation power of the electro-Fenton process using a BDD anode was demonstrated. The oxidative degradation of RNTD by the electrochemically generated OH radicals obeyed a pseudo-first order kinetics. The absolute rate constant for its hydroxylation reaction was 3.39 × 109 M−1 s−1 as determined by the competition kinetics method. Almost complete mineralization of the RNTN solution was reached by using a BDD anode in both anodic oxidation with electrogenerated H2O2 and electro-Fenton processes. Up to 11 cyclic intermediates with furan moiety were detected from the degradation of RNTD, which were afterwards oxidized to short-chain carboxylic acids before their mineralization to CO2 and inorganic ions such as NH4+, NO3− and SO42−. Based on identified products, a plausible reaction pathway was proposed for RNTD mineralization. Toxicity assessment by the Microtox® method revealed that some cyclic intermediates are more toxic than the parent molecule. Toxicity was quickly removed following the almost total mineralization of the treated solution. Overall results confirm the effectiveness of EAOPs for the efficient removal of RNTD and its oxidation by-products from water.

Revisiting Traditional Risk Factors for Rejection and Graft Loss after Kidney Transplantation

PubMed Central

Dunn, TB; Noreen, H; Gillingham, K; Maurer, D; Ozturk, O. Goruroglu; Pruett, TL; Bray, RA; Gebel, HM; Matas, AJ

2011-01-01

Single antigen bead (SAB) testing permits reassessment of immunologic risk for kidney transplantation. Traditionally, high panel reactive antibody (PRA), retransplant and deceased donor (DD) grafts have been associated with increased risk. We hypothesized that this risk was likely mediated by (unrecognized) donor-specific antibody (DSA). We grouped 587 kidney transplants using clinical history and SAB testing of day of transplant serum as 1) unsensitized; PRA=0 (n= 178), 2) 3rd party sensitized; no DSA (n=363), or 3) donor sensitized; with DSA (n=46), and studied rejection rates, death censored graft survival (DCGS), and risk factors for rejection. Antibody-mediated rejection (AMR) rates were increased with DSA (p<0.0001), but not with PRA in the absence of DSA. Cell-mediated rejection (CMR) rates were increased with DSA (p<0.005); with a trend to increased rates when PRA>0 in the absence of DSA (p=0.08). Multivariate analyses showed risk factors for AMR were DSA, worse HLA matching, and female gender; for CMR: DSA, PRA>0 and worse HLA matching. AMR and CMR were associated with decreased DCGS. The presence of DSA is an important predictor of rejection risk, in contrast to traditional risk factors. Further development of immunosuppressive protocols will be facilitated by stratification of rejection risk by donor sensitization. PMID:21812918

Comparison of sulfuric and oxalic acid anodizing for preparation of thermal control coatings for spacecraft

NASA Technical Reports Server (NTRS)

Le, Huong G.; Watcher, John M.; Smith, Charles A.

1988-01-01

The development of thermal control surfaces, which maintain stable solar absorptivity and infrared emissivity over long periods, is challenging due to severe conditions in low-Earth orbit (LEO). Some candidate coatings are second-surface silver-coated Teflon; second-surface, silvered optical solar reflectors made of glass or quartz; and anodized aluminum. Sulfuric acid anodized and oxalic acid anodized aluminum was evaluated under simulated LEO conditions. Oxalic acid anodizing shows promise of greater stability in LEO over long missions, such as the 30 years planned for the Space Station. However, sulfuric acid anodizing shows lower solar absorptivity.

A stable organic-inorganic hybrid layer protected lithium metal anode for long-cycle lithium-oxygen batteries

NASA Astrophysics Data System (ADS)

Zhu, Jinhui; Yang, Jun; Zhou, Jingjing; Zhang, Tao; Li, Lei; Wang, Jiulin; Nuli, Yanna

2017-10-01

A stable organic-inorganic hybrid layer (OIHL) is direct fabricated on lithium metal surface by the interfacial reaction of lithium metal foil with 1-chlorodecane and oxygen/carbon dioxide mixed gas. This favorable OIHL is approximately 30 μm thick and consists of lithium alkyl carbonate and lithium chloride. The lithium-oxygen batteries with OIHL protected lithium metal anode exhibit longer cycle life (340 cycles) than those with bare lithium metal anode (50 cycles). This desirable performance can be ascribed to the robust OIHL which prevents the growth of lithium dendrites and the corrosion of lithium metal.

Enhanced cycling performance of a Li metal anode in a dimethylsulfoxide-based electrolyte using highly concentrated lithium salt for a lithium-oxygen battery

NASA Astrophysics Data System (ADS)

Togasaki, Norihiro; Momma, Toshiyuki; Osaka, Tetsuya

2016-03-01

Stable charge-discharge cycling behavior for a lithium metal anode in a dimethylsulfoxide (DMSO)-based electrolyte is strongly desired of lithium-oxygen batteries, because the Li anode is rapidly exhausted as a result of side reactions during cycling in the DMSO solution. Herein, we report a novel electrolyte design for enhancing the cycling performance of Li anodes by using a highly concentrated DMSO-based electrolyte with a specific Li salt. Lithium nitrate (LiNO3), which forms an inorganic compound (Li2O) instead of a soluble product (Li2S) on a lithium surface, exhibits a >20% higher coulombic efficiency than lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium perchlorate, regardless of the loading current density. Moreover, the stable cycling of Li anodes in DMSO-based electrolytes depends critically on the salt concentration. The highly concentrated electrolyte 4.0 M LiNO3/DMSO displays enhanced and stable cycling performance comparable to that of carbonate-based electrolytes, which had not previously been achieved. We suppose this enhancement is due to the absence of free DMSO solvent in the electrolyte and the promotion of the desolvation of Li ions on the solid electrolyte interphase surface, both being consequences of the unique structure of the electrolyte.

Donor Specific Anti-HLA Antibodies with Antibody Mediated Rejection and Long-term Outcomes Following Heart Transplantation

PubMed Central

Clerkin, Kevin J.; Farr, Maryjane A.; Restaino, Susan W.; Zorn, Emmanuel; Latif, Farhana; Vasilescu, Elena R.; Marboe, Charles C.; Colombo, Paolo C.; Mancini, Donna M.

2017-01-01

Introduction Donor specific anti-HLA antibodies (DSA) are common following heart transplantation and are associated with rejection, cardiac allograft vasculopathy (CAV), and mortality. Currently a non-invasive diagnostic test for pathologic AMR (pAMR) does not exist. Methods 221 consecutive adult patients underwent heart transplantation from January 1st, 2010 through August 31th, 2013 and followed through October 1st, 2015. The primary objective was to determine whether the presence of DSA could detect AMR at the time of pathologic diagnosis. Secondary analyses included the association of DSA (stratified by MHC Class and de-novo status) during AMR with new graft dysfunction, graft loss (mortality or retransplantation), and development of CAV. Results During the study period 69 individual patients (31.2%) had DSA (24% had de-novo DSA) and there were 74 episodes of pAMR in 38 unique patients. The sensitivity of DSA at any MFI to detect concurrent pAMR was only 54.3%. The presence of any DSA during pAMR increased the odds of graft dysfunction (OR 5.37, 95% CI 1.34–21.47, p=0.018), adjusting for age, gender, and timing of AMR. Circulating Class II DSA after transplantation increased the risk of future pAMR (HR 2.97, 95% CI 1.31–6.73, p=0.009). Patients who developed de-novo Class II DSA had a 151% increase in risk of graft loss (contingent on 30-day survival) compared with those who did not have DSA (95% CI 1.11–5.69, p=0.027). Conclusions DSA were inadequate to diagnose pAMR, but Class II DSA provided prognostic information regarding future pAMR, graft dysfunction with pAMR, and graft loss. PMID:27916323

Donor-specific anti-HLA antibodies with antibody-mediated rejection and long-term outcomes following heart transplantation.

PubMed

Clerkin, Kevin J; Farr, Maryjane A; Restaino, Susan W; Zorn, Emmanuel; Latif, Farhana; Vasilescu, Elena R; Marboe, Charles C; Colombo, Paolo C; Mancini, Donna M

2017-05-01

Donor-specific anti-HLA antibodies (DSA) are common after heart transplantation and are associated with rejection, cardiac allograft vasculopathy, and mortality. A noninvasive diagnostic test for pathologic antibody-mediated rejection (pAMR) does not exist. From January 1, 2010, through August 31, 2013, 221 consecutive adult patients underwent heart transplantation and were followed through October 1, 2015. The primary objective was to determine whether the presence of DSA could detect AMR at the time of pathologic diagnosis. Secondary analyses included association of DSA (stratified by major histocompatibility complex class and de novo status) during AMR with new graft dysfunction, graft loss (mortality or retransplantation), and development of cardiac allograft vasculopathy. During the study period, 69 patients (31.2%) had DSA (24% had de novo DSA), and there were 74 episodes of pAMR in 38 patients. Sensitivity of DSA at any mean fluorescence intensity to detect concurrent pAMR was only 54.3%. The presence of any DSA during pAMR increased the odds of graft dysfunction (odds ratio = 5.37; 95% confidence interval [CI], 1.34-21.47; p = 0.018), adjusting for age, sex, and timing of AMR. Circulating class II DSA after transplantation increased risk of future pAMR (hazard ratio = 2.97; 95% CI, 1.31-6.73; p = 0.009). Patients who developed de novo class II DSA had 151% increased risk of graft loss (contingent on 30-day survival) compared with patients who did not have DSA (95% CI, 1.11-5.69; p = 0.027). DSA were inadequate to diagnose pAMR. Class II DSA provided prognostic information regarding future pAMR, graft dysfunction with pAMR, and graft loss. Copyright © 2017 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Donor-specific HLA alloantibodies: Impact on cardiac allograft vasculopathy, rejection, and survival after pediatric heart transplantation.

PubMed

Tran, Andrew; Fixler, David; Huang, Rong; Meza, Tiffany; Lacelle, Chantale; Das, Bibhuti B

2016-01-01

There is increasing evidence that donor-specific anti-HLA antibodies (DSA) are associated with poor outcomes after cardiac transplantation in adults, but data are limited in children. The objective of this study was to examine the development and consequences of de novo DSA in pediatric recipients of heart transplants. We analyzed 105 pediatric patients who received heart transplants at our center from January 2002 to December 2012. All patients had negative T-cell and B-cell post-transplant crossmatches. Patients underwent HLA antibody screening at 1, 2, 3, 6, and 12 months post-transplant and annually thereafter unless there was suspicion for rejection. HLA class I and II antibodies were identified using Luminex assay. Coronary angiography was performed at 1 year and annually thereafter. Acute cellular rejection, antibody-mediated rejection, and treated clinical rejections were included together as rejection events. Of 105 patients, 45 (43%) developed de novo DSA. DSA-positive patients had significantly higher rates of coronary artery vasculopathy (CAV) compared with DSA-negative patients (36% vs 13%). CAV-free survival at 1 year and 5 years post-transplant for DSA-negative patients was 90% and 25%, respectively, compared with 70% and 0%, respectively, for DSA-positive patients (p < 0.01). DSA-positive patients had 2.5 times more rejection events per year than DSA-negative patients. The 5-year graft survival rate was 72.4% for DSA-negative patients and 21% for DSA-positive patients (p < 0.001). De novo DSA has a strong negative impact on CAV, rejection, and graft survival in pediatric recipients of heart transplants. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Balloon-Occluded Carbon Dioxide Gas Angiography for Internal Iliac Arteriography and Intervention.

PubMed

Kishino, Mitsuhiro; Nakaminato, Shuichiro; Kitazume, Yoshio; Miyasaka, Naoyuki; Kudo, Toshifumi; Saida, Yukihisa; Tateishi, Ukihide

2018-07-01

The usefulness of carbon dioxide (CO 2 ) gas digital subtraction angiography (DSA) has been reported for patients with renal insufficiency and allergy to iodinated contrast agents. However, CO 2 gas cannot replace the iodinated contrast agent in all cases owing to some disadvantages. We describe balloon-occluded CO 2 DSA (B-CO 2 DSA) as an improved CO 2 DSA procedure for interventions in the internal iliac artery (IIA) region and compare the quality of images obtained using conventional CO 2 DSA and B-CO 2 DSA. B-CO 2 DSA-guided embolization was performed for one case of genital bleeding with an acute anaphylactic reaction to the iodinated contrast agent and for three cases of type II endoleaks after endovascular abdominal aortic aneurysm repair with renal dysfunction. A 9-mm occlusion balloon catheter was placed just after the orifice of the IIA. Then, 10-15 ml of CO 2 gas was injected manually via the catheter with and without balloon occlusion. The quality of sequential digital subtraction angiograms was analyzed based on a scoring criterion. In all four cases, image quality was improved with B-CO 2 DSA; the poor quality of images without balloon occlusion was because of reflux of the CO 2 gas. B-CO 2 DSA improves the image quality of CO 2 DSA in the IIA region and is useful for vascular intervention. Level IV.

Prospective Monitoring of Donor-specific Anti-HLA Antibodies After Intestine/Multivisceral Transplantation: Significance of De Novo Antibodies.

PubMed

Kubal, Chandrashekhar; Mangus, Richard; Saxena, Romil; Lobashevsky, Andrew; Higgins, Nancy; Fridell, Jonathan; Tector, A Joseph

2015-08-01

Presence of circulating donor-specific antibodies (DSA) may be associated with worse clinical outcomes after intestine/multivisceral transplantation. In 79 intestine/multivisceral recipients, sera were prospectively screened for DSA by Luminex Single antigen test at 1, 3, 6, 9, 12, 18, 24, and 36 months after transplantation. Standard immunosuppression included thymoglobulin-rituximab induction and tacrolimus-prednisone maintenance. C4d staining was performed retrospectively on biopsies in patients that developed acute rejection (AR). Twenty-two (28%) patients developed de novo DSA at a median posttransplant period of 3 (1-36) months. De novo DSA were observed in 10 of 40 liver-including and 12 of 39 liver-excluding transplants (P = 0.57). Occurrence of AR was slightly higher in patients with de novo DSA (45% vs 33%, respectively; P = 0.41). Similarly, chronic rejection (14% vs 5%; P = 0.21) and graft loss due to AR (18% vs 7%; P = 0.14) were numerically higher in patients with de novo DSA. Only 35% patients experiencing AR had circulating de novo DSA at the time of AR. Antibody-mediated rejection was diagnosed in 6 patients based on C4d staining, of these 2 patients had circulating de novo DSA at the time of biopsy. De novo DSA formation, particularly early in the posttransplant course may be associated with trends toward worse outcomes. However, its significance in the pathophysiology of AR remains uncertain. Studies focusing mechanisms of DSA-related graft injury and intragraft DSA detection might provide further insight into this issue.

Revisiting traditional risk factors for rejection and graft loss after kidney transplantation.

PubMed

Dunn, T B; Noreen, H; Gillingham, K; Maurer, D; Ozturk, O G; Pruett, T L; Bray, R A; Gebel, H M; Matas, A J

2011-10-01

Single-antigen bead (SAB) testing permits reassessment of immunologic risk for kidney transplantation. Traditionally, high panel reactive antibody (PRA), retransplant and deceased donor (DD) grafts have been associated with increased risk. We hypothesized that this risk was likely mediated by (unrecognized) donor-specific antibody (DSA). We grouped 587 kidney transplants using clinical history and single-antigen bead (SAB) testing of day of transplant serum as (1) unsensitized; PRA = 0 (n = 178), (2) third-party sensitized; no DSA (n = 363) or (3) donor sensitized; with DSA (n = 46), and studied rejection rates, death-censored graft survival (DCGS) and risk factors for rejection. Antibody-mediated rejection (AMR) rates were increased with DSA (p < 0.0001), but not with panel reactive antibody (PRA) in the absence of DSA. Cell-mediated rejection (CMR) rates were increased with DSA (p < 0.005); with a trend to increased rates when PRA>0 in the absence of DSA (p = 0.08). Multivariate analyses showed risk factors for AMR were DSA, worse HLA matching, and female gender; for CMR: DSA, PRA>0 and worse HLA matching. AMR and CMR were associated with decreased DCGS. The presence of DSA is an important predictor of rejection risk, in contrast to traditional risk factors. Further development of immunosuppressive protocols will be facilitated by stratification of rejection risk by donor sensitization. ©2011 The Authors Journal compilation©2011 The American Society of Transplantation and the American Society of Transplant Surgeons.

Concordance of Time-of-Flight MRA and Digital Subtraction Angiography in Adult Primary Central Nervous System Vasculitis.

PubMed

de Boysson, H; Boulouis, G; Parienti, J-J; Touzé, E; Zuber, M; Arquizan, C; Dequatre, N; Detante, O; Bienvenu, B; Aouba, A; Guillevin, L; Pagnoux, C; Naggara, O

2017-10-01

3D-TOF-MRA and DSA are 2 available tools to demonstrate neurovascular involvement in primary central nervous system vasculitis. We aimed to compare the diagnostic concordance of vessel imaging using 3D-TOF-MRA and DSA in patients with primary central nervous system vasculitis. We retrospectively identified all patients included in the French primary central nervous system vasculitis cohort of 85 patients who underwent, at baseline, both intracranial 3D-TOF-MRA and DSA in an interval of no more than 2 weeks and before treatment initiation. Two neuroradiologists independently reviewed all 3D-TOF-MRA and DSA imaging. Brain vasculature was divided into 25 arterial segments. Concordance between 3D-TOF-MRA and DSA for the identification of arterial stenosis was assessed by the Cohen κ Index. Thirty-one patients met the inclusion criteria, including 20 imaged with a 1.5T MR unit and 11 with a 3T MR unit. Among the 25 patients (81%) with abnormal DSA findings, 24 demonstrated abnormal 3D-TOF-MRA findings, whereas all 6 remaining patients with normal DSA findings had normal 3D-TOF-MRA findings. In the per-segment analysis, concordance between 1.5T 3D-TOF-MRA and DSA was 0.82 (95% CI, 0.75-0.93), and between 3T 3D-TOF-MRA and DSA, it was 0.87 (95% CI, 0.78-0.91). 3D-TOF-MRA shows a high concordance with DSA in diagnostic performance when analyzing brain vasculature in patients with primary central nervous system vasculitis. In patients with negative 3T 3D-TOF-MRA findings, the added diagnostic value of DSA is limited. © 2017 by American Journal of Neuroradiology.

Digital Subtraction Angiography or Computed Tomography Angiography in the Preoperative Evaluation of Lower Limb Peripheral Artery Disease - A Comparative Analysis.

PubMed

Dias-Neto, Marina; Marques, Catarina; Sampaio, Sérgio

2017-01-01

For several years, digital subtraction angiography (DSA) was considered the gold standard method for the evaluation of PAD patients. This is an invasive technique and allows a good evaluation of collaterals and the vessel lumen, even in cases with associated calcification. Nevertheless, recent technical development of computed tomography angiography (CTA) has improved its specificity and sensibility, besides the fact that CTA is a fast and non-invasive procedure. To characterize a cohort of lower limb PAD patients and clarify if there are differences among the patients preoperatively evaluated by DSA or CTA. This retrospective study focused on PAD patients with a Rutherford classification ≥ 3 and submitted to intervention (endovascular revascularization or open surgery). The CTA group included all patients submitted to this method as their preoperative exam, between March 2009 and April 2017. In the same period of time, patients submitted to DSA as their preoperative exam, were randomly selected. The exclusion criteria were: realization of the exam for a different diagnosis than PAD, amputation not preceded by revascularization, absence of intervention during a period of 1 year after the realization of the exam. The groups were compared upon the type of surgery (open vs endovascular), number of revascularization sectors, reintervention, amputation, mortality and length of hospital stay. 34 CTA patients and 71 DSA patients were included. The groups were demographically and clinically homogeneous. In what regards to arterial lesions, the DSA group showed more often lesions of the distal sector with TASC C or D classification (25% in DSA group and 0% in CTA group; p=0,001), as well as scarcity of runoff vessels (0 or 1 in 72% of DSA patients group and 26% in CTA group; p=0.001). There were no differences about the endovascular and open surgery ratio (1.8 to CTA and 1.4 to DSA; p=0.305), reintervention rates (21% CTA and 16% DSA; p=0.517), major amputation (9% CTA and 11% DSA; p=1), minor amputation (9% CTA and 16% DSA; p=0.541), mortality (18% CTA and 23% DSA; p=0,602), or length of hospital stay (median and (interquartile range) of 14 (27) for CTA and 14 (17) for DSA; p=0.933). CTA seems to be a method for morphological and therapeutic planning of PAD that is non-inferior to DSA.

Community structure dynamics during startup in microbial fuel cells - The effect of phosphate concentrations.

PubMed

Yanuka-Golub, Keren; Reshef, Leah; Rishpon, Judith; Gophna, Uri

2016-07-01

For microbial fuel cells (MFCs) to become a cost-effective wastewater treatment technology, they must produce a stable electro-active microbial community quickly and operate under realistic wastewater nutrient conditions. The composition of the anodic-biofilm and planktonic-cells communities was followed temporally for MFCs operated under typical laboratory phosphate concentrations (134mgL(-1)P) versus wastewater phosphate concentrations (16mgL(-1)P). A stable peak voltage was attained two-fold faster in MFCs operating under lower phosphate concentration. All anodic-biofilms were composed of well-known exoelectrogenic bacterial families; however, MFCs showing faster startup and a stable voltage had a Desulfuromonadaceae-dominated-biofilm, while biofilms co-dominated by Desulfuromonadaceae and Geobacteraceae characterized slower or less stable MFCs. Interestingly,planktonic-cell concentrations of these bacteria followed a similar trend as the anodic-biofilm and could therefore serve as a biomarker for its formation. These results demonstrate that wastewater-phosphate concentrations do not compromise MFCs efficiency, and considerably speed up startup times. Copyright © 2016 Elsevier Ltd. All rights reserved.

Graft Immunocomplex Capture Fluorescence Analysis to Detect Donor-Specific Antibodies and HLA Antigen Complexes in the Allograft.

PubMed

Nakamura, Tsukasa; Ushigome, Hidetaka; Watabe, Kiyoko; Imanishi, Yui; Masuda, Koji; Matsuyama, Takehisa; Harada, Shumpei; Koshino, Katsuhiro; Iida, Taku; Nobori, Shuji; Yoshimura, Norio

2017-04-01

Immunocomplex capture fluorescence analysis (ICFA) is an attractive method to detect donor-specific anti-HLA antibodies (DSA) and HLA antigen complexes. Currently, antibody-mediated rejection (AMR) due to DSA is usually diagnosed by C4d deposition and serological DSA detection. Conversely, there is a discrepancy between these findings frequently. Thereupon, our graft ICFA technique may contribute to establish the diagnosis of AMR. Graft samples were obtained by a percutaneous needle biopsy. Then, the specimen was dissolved in PBS by the lysis buffer. Subsequently, HLA antigens were captured by anti-HLA beads. Then, DSA-HLA complexes were detected by PE-conjugated anti-human IgG antibodies, where DSA had already reacted with the allograft in vivo, analyzed by a Luminex system. A ratio (sample MFI/blank beads MFI) was calculated: ≥ 1.0 was determined as positive. We found that DSA-HLA complexes in the graft were successfully detected from only slight positive 1.03 to 79.27 in a chronic active AMR patient by graft ICFA. Next, positive graft ICFA had predicted the early phase of AMR (MFI ratio: 1.38) even in patients with no serum DSA. Finally, appropriate therapies for AMR deleted DSA deposition (MFI ratio from 0.3 to 0.7) from allografts. This novel application would detect early phase or incomplete pathological cases of AMR, which could lead to a correct diagnosis and initiation of appropriate therapies. Moreover, graft ICFA might address a variety of long-standing questions in terms of DSA. AMR: Antibody-mediated rejection; DSA: Donor-specific antibodies; ICFA: Immunocomplex capture fluorescence analysis.

Characteristics of Donor-Specific Antibodies Associated With Antibody-Mediated Rejection in Lung Transplantation

PubMed Central

Roux, Antoine; Bendib Le Lan, Ines; Holifanjaniaina, Sonia; Thomas, Kimberly A.; Picard, Clément; Grenet, Dominique; De Miranda, Sandra; Douvry, Benoit; Beaumont-Azuar, Laurence; Sage, Edouard; Devaquet, Jérôme; Cuquemelle, Elise; Le Guen, Morgan; Suberbielle, Caroline; Gautreau, Chantal; Stern, Marc; Rossetti, Maura; Hamid, Abdul Monem; Parquin, Francois

2017-01-01

Although donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) are frequently found in recipients after lung transplantation (LT), the characteristics of DSA which influence antibody-mediated rejection (AMR) in LT are not fully defined. We retrospectively analyzed 206 consecutive LT patients of our center (2010–2013). DSAs were detected by using luminex single antigen beads assay and mean fluorescence intensity was assessed. Within the study population, 105 patients had positive DSA. Patients with and without AMR (AMRPos, n = 22, and AMRNeg, n = 83, respectively) were compared. AMRPos patients had significantly greater frequencies of anti-HLA DQ DSA (DQ DSA) than AMRNeg patients (95 vs 58%, respectively, p < 0.0001). Compared to AMRNeg patients, AMRPos patients had higher DQ DSA sum MFI [7,332 (2,067–10,213) vs 681 (0–1,887), p < 0.0001]. DQ DSA when associated with AMR, had more frequent graft loss and chronic lung allograft dysfunction (CLAD). These data suggest (i) that DSA characteristics clearly differ between AMRPos and AMRNeg patients and (ii) the deleterious impact of DQ DSA on clinical outcome. PMID:29075627

Tris(trimethylsilyl) Phosphite as an Efficient Electrolyte Additive To Improve the Surface Stability of Graphite Anodes.

PubMed

Yim, Taeeun; Han, Young-Kyu

2017-09-27

Tris(trimethylsilyl) phosphite (TMSP) has received considerable attention as a functional additive for various cathode materials in lithium-ion batteries, but the effect of TMSP on the surface stability of a graphite anode has not been studied. Herein, we demonstrate that TMSP serves as an effective solid electrolyte interphase (SEI)-forming additive for graphite anodes in lithium-ion batteries (LIBs). TMSP forms SEI layers by chemical reactions between TMSP and a reductively decomposed ethylene carbonate (EC) anion, which is strikingly different from the widely known mechanism of the SEI-forming additives. TMSP is stable under cathodic polarization, but it reacts chemically with radical anion intermediates derived from the electrochemical reduction of the carbonate solvents to generate a stable SEI layer. These TMSP-derived SEI layers improve the interfacial stability of the graphite anode, resulting in a retention of 96.8% and a high Coulombic efficiency of 95.2%. We suggest the use of TMSP as a functional additive that effectively stabilizes solid electrolyte interfaces of both the anode and cathode in lithium-ion batteries.

A siloxane-incorporated copolymer as an in situ cross-linkable binder for high performance silicon anodes in Li-ion batteries

NASA Astrophysics Data System (ADS)

Jeena, M. T.; Bok, Taesoo; Kim, Si Hoon; Park, Sooham; Kim, Ju-Young; Park, Soojin; Ryu, Ja-Hyoung

2016-04-01

The electrochemical performance of Li-ion batteries (LIBs) can be highly tuned by various factors including the morphology of the anode material, the nature of the electrolyte, the binding material, and the percentage of conducting materials. Binding materials have been of particular interest to researchers over the decades as a means to further improve the cycle durability and columbic efficiency of LIBs. Such approaches include the introduction of different polymeric binders such as poly(acrylic acid) (PAA), carboxymethyl cellulose (CMC), and alginic acid (Alg) into the Si anode of LIBs. To achieve a better efficiency of LIBs, herein, we introduce a novel copolymer, poly(tert-butyl acrylate-co-triethoxyvinylsilane) (TBA-TEVS), as an efficient binder with stable cycle retention and excellent specific capacity. The binder forms a highly interconnected three-dimensional network upon thermal treatment as a result of de-protection of the tert-butyl group and the consequent inter-intra condensation reaction, which minimizes pulverization of the Si nanoparticles. Moreover, the siloxane group is expected to promote the formation of stable solid-electrolyte-interface (SEI) layers. A series of random copolymers were synthesized by varying the molar ratio of tert-butyl acrylate and triethoxyvinylsilane. Twenty-one percent of TEVS in the TBS-TEVS copolymer gave rise to a superior performance as a binder for Si anodes, where the anodes showed a stable specific capacity of 2551 mA h g-1 over hundreds of cycles and an initial columbic efficiency (ICE) of 81.8%.The electrochemical performance of Li-ion batteries (LIBs) can be highly tuned by various factors including the morphology of the anode material, the nature of the electrolyte, the binding material, and the percentage of conducting materials. Binding materials have been of particular interest to researchers over the decades as a means to further improve the cycle durability and columbic efficiency of LIBs. Such approaches include the introduction of different polymeric binders such as poly(acrylic acid) (PAA), carboxymethyl cellulose (CMC), and alginic acid (Alg) into the Si anode of LIBs. To achieve a better efficiency of LIBs, herein, we introduce a novel copolymer, poly(tert-butyl acrylate-co-triethoxyvinylsilane) (TBA-TEVS), as an efficient binder with stable cycle retention and excellent specific capacity. The binder forms a highly interconnected three-dimensional network upon thermal treatment as a result of de-protection of the tert-butyl group and the consequent inter-intra condensation reaction, which minimizes pulverization of the Si nanoparticles. Moreover, the siloxane group is expected to promote the formation of stable solid-electrolyte-interface (SEI) layers. A series of random copolymers were synthesized by varying the molar ratio of tert-butyl acrylate and triethoxyvinylsilane. Twenty-one percent of TEVS in the TBS-TEVS copolymer gave rise to a superior performance as a binder for Si anodes, where the anodes showed a stable specific capacity of 2551 mA h g-1 over hundreds of cycles and an initial columbic efficiency (ICE) of 81.8%. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01559j

Anode Fall As Relevant to Plasma Thrusters.

DTIC Science & Technology

1997-06-01

considered, whether induced or external magnetic fields are included, as to how the flow chemistry is modeled, among others. For the cathode, sheath...the extent of the anode fall region, a region where flow chemistry becomes paramount, determining plasma equilibrium. But is the anode fall stable...i * =n* * = =0 and when the plasma boundary is approached. The latter condition immediately emphasizes the flow chemistry , ionization and

[Effect of the initial anode potential on electricity generation in microbial fuel cell].

PubMed

Fan, Ming-Zhi; Liang, Peng; Cao, Xiao-Xin; Huang, Xia

2008-01-01

The initial anode potential of the microbial fuel cell (MFC) was changed by additional circuit in the anode chamber, and the influence of the initial anode potential on the electricigens was studied. When the initial anode potential was 350 mV (vs Hg/Hg2 Cl2), the growth of microorganisms was much slower than that of the microorganisms which grew on the anode with an initial potential of -200 mV or 200 mV (vs Hg/Hg2 Cl2). After stable electricity generation, the anode resistances of the three MFCs, which had initial anode potentials of 350 mV, 200 mV and -200 mV respectively, were 71 Omega, 43 Omega and 80 Omega. The community structures in MFCs, before and after the electricity generation, were also studied by denaturing gradient gel electrophoresis (DGGE). Clostridium sticklandii, Pseudomonas mendocina and Paenibacillus taejonensis were the three most enriched strains on the anode.

Self-assembled templates for the generation of arrays of 1-dimensional nanostructures: from molecules to devices.

PubMed

Farrell, Richard A; Petkov, Nikolay; Morris, Michael A; Holmes, Justin D

2010-09-15

Self-assembled nanoscale porous architectures, such as mesoporous silica (MPS) films, block copolymer films (BCP) and porous anodic aluminas (PAAs), are ideal hosts for templating one dimensional (1D) nano-entities for a wide range of electronic, photonic, magnetic and environmental applications. All three of these templates can provide scalable and tunable pore diameters below 20 nm [1-3]. Recently, research has progressed towards controlling the pore direction, orientation and long-range order of these nanostructures through so-called directed self-assembly (DSA). Significantly, the introduction of a wide range of top-down chemically and physically pre-patterning substrates has facilitated the DSA of nanostructures into functional device arrays. The following review begins with an overview of the fundamental aspects of self-assembly and ordering processes during the formation of PAAs, BCPs and MPS films. Special attention is given to the different ways of directing self-assembly, concentrating on properties such as uni-directional alignment, precision placement and registry of the self-assembled structures to hierarchal or top-down architectures. Finally, to distinguish this review from other articles we focus on research where nanostructures have been utilised in part to fabricate arrays of functioning devices below the sub 50 nm threshold, by subtractive transfer and additive methods. Where possible, we attempt to compare and contrast the different templating approaches and highlight the strengths and/or limitations that will be important for their potential integration into downstream processes. Copyright 2010 Elsevier Inc. All rights reserved.

A Critical Analysis of the Utility of Intraoperative Angiography.

PubMed

Ares, William J; Kenmuir, Cynthia L; Panczykowski, David M; Weiner, Gregory M; Jadhav, Ashu P; Jovin, Tudor G; Gross, Bradley A; Jankowitz, Brian T

2018-02-01

Intraoperative digital subtraction angiography (ioDSA) is touted as the gold standard imaging evaluation for aneurysm clip constructs. Candid evaluations of its limitations are sparse. A prospectively collected hospital billing database was queried to identify craniotomies for aneurysm clipping from January 2010 to December 2013. We evaluated the rate of occult residual and parent vessel stenosis determined on follow-up angiography for patients undergoing ioDSA and those not undergoing ioDSA. Comparisons were performed via Fisher exact test, with P < 0.05 considered statistically significant. From our database search, we found 187 patients who underwent ioDSA after aneurysm clipping and an additional 91 patients who did not. Results from ioDSA influenced operative management in 17% of cases. Sixty-four patients with 70 treated aneurysms undergoing ioDSA had postoperative angiography; 7 occult residuals were discovered, yielding a 10% false-negative rate, with 10% of aneurysms showing residual. Occult residuals at the middle cerebral artery bifurcation represented most discovered residuals (6/7). Thirty-two patients with 37 treated aneurysms did not undergo ioDSA and had angiographic follow-up; 24% of patients were found to have residual aneurysms (P = 0.08 compared with patients undergoing ioDSA). Residuals at the anterior communicating artery (ACoA) represented 56% of all residuals, whereas the ACoA represented only 18% of aneurysms clipped. The rate of residuals was significantly higher than that for patients with clipped ACoA aneurysms undergoing ioDSA (P = 0.008). ioDSA influenced management in nearly one fifth of cases. It can be particularly beneficial in detecting residuals for ACoA aneurysms; its benefit was less apparent for middle cerebral artery aneurysms. Copyright © 2017 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aoyama, Hidefumi; Shirato, Hiroki; Katoh, Norio

Purpose: To investigate the discrepancy between the arteriovenous malformations seen on magnetic resonance angiography (MRA) and on stereotactic digital subtracted angiography (DSA). Methods and Materials: The target volume on stereotactic DSA (V{sub DSA} ) and the target volume on MRA (V{sub MRA} ) were separately delineated in 28 intracranial arteriovenous malformations. The coordinates of the center and the outer edges of V{sub DSA} and V{sub MRA} were calculated and used for the analyses. Results: The standard deviations (mean value) of the displacement of centers of V{sub MRA} from V{sub DSA} were 2.67 mm (-1.82 mm) in the left-right direction, 3.23more » mm (-0.08 mm) in the anterior-posterior direction, and 2.16 mm (0.91 mm) in the craniocaudal direction. V{sub MRA} covered less than 80% of V{sub DSA} in any dimensions in 9 cases (32%), although no significant difference was seen in the target volume between each method, with a mean value of 11.9 cc for V{sub DSA} and 12.3 cc for V{sub MRA} (p = 0.948). Conclusion: The shift of centers between each modality is not negligible. Considering no significant difference between V{sub DSA} and V{sub MRA} , but inadequate coverage of the V{sub DSA} by V{sub MRA} , it is reasonable to consider that the target on MRA might include the feeding artery and draining vein and possibly miss a portion of the nidus.« less

Donor-specific antibodies require preactivated immune system to harm renal transplant.

PubMed

Süsal, Caner; Döhler, Bernd; Ruhenstroth, Andrea; Morath, Christian; Slavcev, Antonij; Fehr, Thomas; Wagner, Eric; Krüger, Bernd; Rees, Margaret; Balen, Sanja; Živčić-Ćosić, Stela; Norman, Douglas J; Kuypers, Dirk; Emonds, Marie-Paule; Pisarski, Przemyslaw; Bösmüller, Claudia; Weimer, Rolf; Mytilineos, Joannis; Scherer, Sabine; Tran, Thuong H; Gombos, Petra; Schemmer, Peter; Zeier, Martin; Opelz, Gerhard

2016-07-01

It is an unresolved issue why some kidney transplant recipients with pretransplant donor-specific HLA antibodies (DSA) show a high transplant failure rate, whereas in other patients DSA do not harm the graft. We investigated whether help from preactivated T-cells might be necessary for DSA to exert a deleterious effect. The impact of pretransplant DSA and immune activation marker soluble CD30 (sCD30) on 3-year graft survival was analyzed in 385 presensitized kidney transplant recipients. A deleterious influence of pretransplant DSA on graft survival was evident only in patients who were positive for the immune activation marker sCD30. In the absence of sCD30 positivity, 3-year graft survival was virtually identical in patients with or without DSA (83.1±3.9% and 84.3±2.8%, P=0.81). A strikingly lower 3-year graft survival rate of 62.1±6.4% was observed in patients who were both sCD30 and DSA positive (HR 2.92, P<0.001). Even in the presence of strong DSA with ≥5000 MFI, the 3-year graft survival rate was high if the recipients were sCD30 negative. Pretransplant DSA have a significantly deleterious impact on graft survival only in the presence of high pretransplant levels of the activation marker sCD30. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Gasoline-fueled solid oxide fuel cell using MoO2-Based Anode

NASA Astrophysics Data System (ADS)

Hou, Xiaoxue; Marin-Flores, Oscar; Kwon, Byeong Wan; Kim, Jinsoo; Norton, M. Grant; Ha, Su

2014-12-01

This short communication describes the performance of a solid oxide fuel cell (SOFC) fueled by directly feeding premium gasoline to the anode without using external reforming. The novel component of the fuel cell that enables such operation is the mixed conductivity of MoO2-based anode. Using this anode, a fuel cell demonstrating a maximum power density of 31 mW/cm2 at 0.45 V was successfully fabricated. Over a 24 h period of operation, the open cell voltage remained stable at ∼0.92 V. Scanning electron microscopy (SEM) examination of the anode surface pre- and post-testing showed no evidence of coking.

Engineering of Nanoscale Antifouling and Hydrophobic Surfaces on Naval Structural Steel HY-80 by Anodizing

DTIC Science & Technology

2015-06-01

examination of the morphologies of the nanoporous structures and the evaluation of the anodization parameters such as anodization potential, time... sponges , anemones, tunicates, and hydroids, whilst hard fouling comprises invertebrates such as barnacles, mussels, and tubeworms. The specific...of metals by making them more stable and highly resistant, but also to modify the surface by giving it a desired morphology . Ferrous alloys such as

Evaluation of electricity production from alkaline pretreated sludge using two-chamber microbial fuel cell.

PubMed

Xiao, Benyi; Yang, Fang; Liu, Junxin

2013-06-15

Electricity production from alkaline pretreated sludge was evaluated using a two-chamber microbial fuel cell (MFC). The electricity production was found to be stable over a long period of time (approximately 17 d) with voltage outputs and power densities of 0.47-0.52 V and 46.80-55.88 mW/m(2), respectively. The anode resistance was the main internal resistance (73.2%) of MFC in the stable stage. Most soluble organic matters (proteins and carbohydrates) in the anode chamber were first degraded and converted into volatile fatty acids (0-15 d), which were then degraded and converted into electricity and methane (15-29 d). The insoluble organics were solubilized thereby decreasing the sludge concentration and reducing the sludge mass. Methane was produced in the anode chamber owing to the growth of methanogens, which did not obviously affect the electricity production. The change in humic-like substances displayed a positive correlation with the electricity production of the MFC. Microbial analysis showed that methanogens and electricity-producing bacteria co-existed mostly on the surface as well as inside the anode. Decreasing the anode resistance and increasing the anode utilization could enhance the electricity production. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Transient analysis of gas transport in anode channel of a polymer electrolyte membrane fuel cell with dead-ended anode under pressure swing operation

NASA Astrophysics Data System (ADS)

Ichikawa, Yasushi; Oshima, Nobuyuki; Tabuchi, Yuichiro; Ikezoe, Keigo

2014-12-01

Further cost reduction is a critical issue for commercialization of fuel-cell electric vehicles (FCEVs) based on polymer electrolyte fuel cells (PEFCs). The cost of the fuel-cell system is driven by the multiple parts required to maximize stack performance and maintain durability and robustness. The fuel-cell system of the FCEV must be simplified while maintaining functionality. The dead-ended anode is considered as a means of simplification in this study. Generally, if hydrogen is supplied under constant pressure during dead-ended operation, stable power generation is impossible because of accumulation of liquid water produced by power generation and of nitrogen via leakage from the cathode through the membrane. Herein, pressure oscillation is applied to address this issue. Empirical and CFD data are employed to elucidate the mechanism of stable power generation using the pressure swing supply. Simultaneous and time-continuous measurements of the current distribution and gas concentration distribution are also conducted. The results demonstrate that the nitrogen concentration in the anode channel under pressure constant operation differs from that under pressure swing supply conditions. The transient two-dimensional CFD results indicate that oscillatory flow is generated by pressure swing supply, which periodically sweeps out nitrogen from the active area, resulting in stable power generation.

Digital subtraction angiography of the pulmonary arteries for the diagnosis of pulmonary embolism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludwig, J.W.; Verhoeven, L.A.J.; Kersbergen, J.J.

1983-06-01

A comparative study of radionuclide scanning (perfusion studies in all 18 patients and ventilation studies in 9) and digital subtraction angiography (DSA) was performed in 18 patients with suspected pulmonary thromboembolism. In 17 patients good visualization of the arteries was obtained with DSA; 10 of these patients had no pre-existing lung disease, and 7 had chronic obstructive pulmonary disease (COPD). The information provided by DSA in this small group was equal to or better than that of scintigraphy, especially in patients with COPD, and the reliability of DSA was superior to that of the radionuclide scintigraphy. Methods for preventing motionmore » artifacts with DSA are also described.« less

Incorporating DSA in multipatterning semiconductor manufacturing technologies

NASA Astrophysics Data System (ADS)

Badr, Yasmine; Torres, J. A.; Ma, Yuansheng; Mitra, Joydeep; Gupta, Puneet

2015-03-01

Multi-patterning (MP) is the process of record for many sub-10nm process technologies. The drive to higher densities has required the use of double and triple patterning for several layers; but this increases the cost of the new processes especially for low volume products in which the mask set is a large percentage of the total cost. For that reason there has been a strong incentive to develop technologies like Directed Self Assembly (DSA), EUV or E-beam direct write to reduce the total number of masks needed in a new technology node. Because of the nature of the technology, DSA cylinder graphoepitaxy only allows single-size holes in a single patterning approach. However, by integrating DSA and MP into a hybrid DSA-MP process, it is possible to come up with decomposition approaches that increase the design flexibility, allowing different size holes or bar structures by independently changing the process for every patterning step. A simple approach to integrate multi-patterning with DSA is to perform DSA grouping and MP decomposition in sequence whether it is: grouping-then-decomposition or decomposition-then-grouping; and each of the two sequences has its pros and cons. However, this paper describes why these intuitive approaches do not produce results of acceptable quality from the point of view of design compliance and we highlight the need for custom DSA-aware MP algorithms.

Vertical Graphene Growth on SiO Microparticles for Stable Lithium Ion Battery Anodes.

PubMed

Shi, Liurong; Pang, Chunlei; Chen, Shulin; Wang, Mingzhan; Wang, Kexin; Tan, Zhenjun; Gao, Peng; Ren, Jianguo; Huang, Youyuan; Peng, Hailin; Liu, Zhongfan

2017-06-14

Silicon-based materials are considered as strong candidates to next-generation lithium ion battery anodes because of their ultrahigh specific capacities. However, the pulverization and delamination of electrochemical active materials originated from the huge volume expansion (>300%) of silicon during the lithiation process results in rapid capacity fade, especially in high mass loading electrodes. Here we demonstrate that direct chemical vapor deposition (CVD) growth of vertical graphene nanosheets on commercial SiO microparticles can provide a stable conducting network via interconnected vertical graphene encapsulation during lithiation, thus remarkably improving the cycling stability in high mass loading SiO anodes. The vertical graphene encapsulated SiO (d-SiO@vG) anode exhibits a high capacity of 1600 mA h/g and a retention up to 93% after 100 cycles at a high areal mass loading of 1.5 mg/cm 2 . Furthermore, 5 wt % d-SiO@vG as additives increased the energy density of traditional graphite/NCA 18650 cell by ∼15%. We believe that the results strongly imply the important role of CVD-grown vertical graphene encapsulation in promoting the commercial application of silicon-based anodes.

Contrast-enhanced time-resolved MRA for pre-angiographic evaluation of suspected spinal dural arterial venous fistulas.

PubMed

Saindane, Amit M; Boddu, Srikanth R; Tong, Frank C; Dehkharghani, Seena; Dion, Jacques E

2015-02-01

Spinal digital subtraction angiography (DSA) is the gold standard for diagnosis of spinal dural arterial venous fistulas (SDAVFs), but can require extensive time, radiation exposure and contrast dose. We hypothesize that contrast-enhanced time-resolved MR angiography (CE-TR MRA) will have utility for the non-invasive diagnosis and pre-angiographic localization of SDAVFs. Eighteen patients underwent both CE-TR MRA and DSA for suspected SDAVFs, with DSA performed a median of 11 days (range 0-41) after MRA. CE-TR MRA was performed on a 1.5 T GE unit using Time Resolved Imaging of Contrast Kinetics (TRICKS). CE-TR MRA and DSA images were evaluated for the presence of SDAVFs and location of the feeding arterial supply, with DSA as the reference standard. DSA was also evaluated for the number of vessels catheterized, contrast volume and fluoroscopic and procedure times. Eight of the 18 patients were positive for SDAVF on DSA. Sensitivity, specificity, positive predictive value and negative predictive value for the 18 CE-TR MRAs were 88%, 90%, 88% and 90%, respectively. Localization of the SDAVF arterial supply on CE-TR MRA was within one vertebral level from DSA for 6/7 SDAVFs. Compared with patients with a SDAVF and feeding artery identified on CE-TR MRA, patients with negative or suboptimal CE-TR MRA had a significantly increased number of vessels catheterized (p=0.027) and larger contrast volumes (p=0.022). CE-TR MRA is a useful initial examination for the diagnosis and localization of SDAVFs, with a high concordance rate with DSA. When CE-TR MRA demonstrates a SDAVF, the number of catheterized vessels and contrast dose can be decreased during DSA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Pre-transplant donor HLA-specific antibodies: characteristics causing detrimental effects on survival after lung transplantation.

PubMed

Smith, John D; Ibrahim, Mohamed W; Newell, Helen; Danskine, Anna J; Soresi, Simona; Burke, Margaret M; Rose, Marlene L; Carby, Martin

2014-10-01

The impact of Luminex-detected HLA antibodies on outcomes after lung transplantation is unclear. Herein we have undertaken a retrospective study of pre-transplant sera from 425 lung transplants performed between 1991 and 2003. Pre-transplant sera, originally screened by complement-dependent cytotoxicity (CDC) assays, were retrospectively tested for the presence of HLA-specific antibodies using HLA-coated Luminex beads and C4d deposition on Luminex beads. The results were correlated with graft survival at 1 year. Twenty-seven patients were retrospectively identified as having been transplanted against donor-specific HLA antibodies (DSA) and 36 patients against non-donor-specific HLA antibodies (NDSA). DSA-positive patients had 1-year survival of 51.9% compared with 77.8% for NDSA and 71.8% for antibody-negative patients (p = 0.029). One-year survival of patients with complement-fixing DSA was 12.5% compared with 62.5% for non-complement-fixing DSA, 75.8% for non-complement-fixing NDSA and 71.8% for antibody-negative patients (p < 0.0001). DSA-positive patients with mean fluorescence intensity (MFI) >5,000 had 1-year survival of 33.3% compared with 71.4% for MFI 2,000 to 5000 and 62.5% for MFI <2,000 (p = 0.0046). Multivariable analysis revealed DSA to be an independent predictor of poor patient survival within 1 year (p = 0.0010, hazard ratio [HR] = 3.569) as well as complement-fixing DSA (p < 0.0001, HR = 11.083) and DSA with MFI >5,000 (p = 0.0001, HR = 5.512). Pre-formed DSA, particularly complement-fixing DSA, and high MFI are associated with poor survival within the first year after lung transplantation. Risk stratification according to complement fixation or MFI levels may allow for increased transplantation in sensitized patients. Copyright © 2014 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Value of Donor–Specific Anti–HLA Antibody Monitoring and Characterization for Risk Stratification of Kidney Allograft Loss

PubMed Central

Viglietti, Denis; Loupy, Alexandre; Vernerey, Dewi; Bentlejewski, Carol; Gosset, Clément; Aubert, Olivier; Duong van Huyen, Jean-Paul; Jouven, Xavier; Legendre, Christophe; Glotz, Denis; Zeevi, Adriana

2017-01-01

The diagnosis system for allograft loss lacks accurate individual risk stratification on the basis of donor–specific anti–HLA antibody (anti-HLA DSA) characterization. We investigated whether systematic monitoring of DSA with extensive characterization increases performance in predicting kidney allograft loss. This prospective study included 851 kidney recipients transplanted between 2008 and 2010 who were systematically screened for DSA at transplant, 1 and 2 years post-transplant, and the time of post–transplant clinical events. We assessed DSA characteristics and performed systematic allograft biopsies at the time of post–transplant serum evaluation. At transplant, 110 (12.9%) patients had DSAs; post-transplant screening identified 186 (21.9%) DSA-positive patients. Post–transplant DSA monitoring improved the prediction of allograft loss when added to a model that included traditional determinants of allograft loss (increase in c statistic from 0.67; 95% confidence interval [95% CI], 0.62 to 0.73 to 0.72; 95% CI, 0.67 to 0.77). Addition of DSA IgG3 positivity or C1q binding capacity increased discrimination performance of the traditional model at transplant and post-transplant. Compared with DSA mean fluorescence intensity, DSA IgG3 positivity and C1q binding capacity adequately reclassified patients at lower or higher risk for allograft loss at transplant (category–free net reclassification index, 1.30; 95% CI, 0.94 to 1.67; P<0.001 and 0.93; 95% CI, 0.49 to 1.36; P<0.001, respectively) and post-transplant (category–free net reclassification index, 1.33; 95% CI, 1.03 to 1.62; P<0.001 and 0.95; 95% CI, 0.62 to 1.28; P<0.001, respectively). Thus, pre– and post–transplant DSA monitoring and characterization may improve individual risk stratification for kidney allograft loss. PMID:27493255

Patient radiation dose from computed tomography angiography and digital subtraction angiography of the brain

NASA Astrophysics Data System (ADS)

Netwong, Y.; Krisanachinda, A.

2016-03-01

The 64-row multidetector computed tomography angiography (64-MDCTA) provides vascular image quality of the brain similar to digital subtraction angiography (DSA), but the effective dose of CTA is lower than DSA studied in phantom. The purpose of this study is to evaluate the effective dose from 64-MDCTA and DSA. Effective dose (according to ICRP 103) from 64-MDCTA and DSA flat panel detector for cerebral vessels examination of the brain using standard protocols as recommended by the manufacturer was calculated for 30 cases of MDCTA (15 male and 15 female).The mean patient age was 49.5 (23-89) yrs. 30 cases of DSA (14 male and 16 female), the mean patient age was 46.8 (21-81) yrs. For CTA, the mean effective dose was 3.7 (2.82- 5.19) mSv. For DSA, the mean effective dose was 5.78 (3.3-10.06) mSv. The effective dose of CTA depends on the scanning protocol and scan length. Low tube current can reduce patient dose whereas the number of exposures and number of series in 3D rotational angiography (3D RA) resulted in increasing effective dose in DSA patients.

[Design and development of the DSA digital subtraction workstation].

PubMed

Peng, Wen-Xian; Peng, Tian-Zhou; Xia, Shun-Ren; Jin, Guang-Bo

2008-05-01

According to the patient examination criterion and the demands of all related departments, the DSA digital subtraction workstation has been successfully designed and is introduced in this paper by analyzing the characteristic of video source of DSA which was manufactured by GE Company and has no DICOM standard interface. The workstation includes images-capturing gateway and post-processing software. With the developed workstation, all images from this early DSA equipment are transformed into DICOM format and then are shared in different machines.

Renal transplantation across the donor-specific antibody barrier: Graft outcome and cancer risk after desensitization therapy.

PubMed

Yang, Ching-Yao; Lee, Chih-Yuan; Yeh, Chi-Chuan; Tsai, Meng-Kun

2016-06-01

Desensitization regimens including use of intravenous immune globulin and rituximab have been reported to overcome renal transplant hyperacute rejection. A retrospective case-control study was performed to assess the results and complications of renal transplantation with desensitization therapy for donor-specific antibody (DSA) in a transplant center in Asia, where donor exchange was usually not allowed. Between January 2007 and December 2013, 22 patients with DSA received live-donor renal transplantation after desensitization (DSA group). During the same period, the DSA group was compared to the NSA group (152 renal transplants) who had no specific antibody to the donors (66 from deceased donors and 86 from living relatives). Rejection, renal function, graft and patient survival rates, infection, and cancer incidence were reviewed and analyzed from medical records. The DSA group (46.8%) had significantly higher acute rejection rates than the NSA group (13.7%) at the 1-year follow-up. The estimated renal function, 5-year graft, and patient survival rates were comparable between the groups. The DSA group (19.6%) had significantly higher 5-year de novo cancer incidence than the NSA group (8.5%; p = 0.028); three patients of the DSA group developed urothelial carcinoma 17.0 ± 3.0 months after transplantation. By using stepwise Cox regression analysis, desensitization therapy was identified as the sole independent risk factor for post-transplant urothelial carcinoma. When compared to renal transplantation without DSA, desensitization therapy for DSA resulted in equivalent renal transplant outcome but potentially increased risk of urothelial carcinoma after transplantation. Copyright © 2015. Published by Elsevier B.V.

Coarse-Graining Polymer Field Theory for Fast and Accurate Simulations of Directed Self-Assembly

NASA Astrophysics Data System (ADS)

Liu, Jimmy; Delaney, Kris; Fredrickson, Glenn

To design effective manufacturing processes using polymer directed self-assembly (DSA), the semiconductor industry benefits greatly from having a complete picture of stable and defective polymer configurations. Field-theoretic simulations are an effective way to study these configurations and predict defect populations. Self-consistent field theory (SCFT) is a particularly successful theory for studies of DSA. Although other models exist that are faster to simulate, these models are phenomenological or derived through asymptotic approximations, often leading to a loss of accuracy relative to SCFT. In this study, we employ our recently-developed method to produce an accurate coarse-grained field theory for diblock copolymers. The method uses a force- and stress-matching strategy to map output from SCFT simulations into parameters for an optimized phase field model. This optimized phase field model is just as fast as existing phenomenological phase field models, but makes more accurate predictions of polymer self-assembly, both in bulk and in confined systems. We study the performance of this model under various conditions, including its predictions of domain spacing, morphology and defect formation energies. Samsung Electronics.

Reaction between Lithium Anode and Polysulfide Ions in a Lithium-Sulfur Battery

DOE PAGES

Zheng, Dong; Yang, Xiao-Qing; Qu, Deyang

2016-08-18

Here, the reaction between polysulfides and a lithium anode in a Li–S battery was examined using HPLC. The results demonstrated that the polysulfide species with six sulfur atoms or more were reactive with regard to lithium metal. Although the reaction can be greatly inhibited by the addition of LiNO 3 in the electrolyte, LiNO 3 cannot form a stable protection layer on the Li anode to prevent the reaction during storage.

Reaction between Lithium Anode and Polysulfide Ions in a Lithium-Sulfur Battery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Dong; Yang, Xiao-Qing; Qu, Deyang

Here, the reaction between polysulfides and a lithium anode in a Li–S battery was examined using HPLC. The results demonstrated that the polysulfide species with six sulfur atoms or more were reactive with regard to lithium metal. Although the reaction can be greatly inhibited by the addition of LiNO 3 in the electrolyte, LiNO 3 cannot form a stable protection layer on the Li anode to prevent the reaction during storage.

Fuel cell electrode interconnect contact material encapsulation and method

DOEpatents

Derose, Anthony J.; Haltiner, Jr., Karl J.; Gudyka, Russell A.; Bonadies, Joseph V.; Silvis, Thomas W.

2016-05-31

A fuel cell stack includes a plurality of fuel cell cassettes each including a fuel cell with an anode and a cathode. Each fuel cell cassette also includes an electrode interconnect adjacent to the anode or the cathode for providing electrical communication between an adjacent fuel cell cassette and the anode or the cathode. The interconnect includes a plurality of electrode interconnect protrusions defining a flow passage along the anode or the cathode for communicating oxidant or fuel to the anode or the cathode. An electrically conductive material is disposed between at least one of the electrode interconnect protrusions and the anode or the cathode in order to provide a stable electrical contact between the electrode interconnect and the anode or cathode. An encapsulating arrangement segregates the electrically conductive material from the flow passage thereby, preventing volatilization of the electrically conductive material in use of the fuel cell stack.

Safety, efficacy, and cost of intraoperative indocyanine green angiography compared to intraoperative catheter angiography in cerebral aneurysm surgery.

PubMed

Hardesty, Douglas A; Thind, Harjot; Zabramski, Joseph M; Spetzler, Robert F; Nakaji, Peter

2014-08-01

Intraoperative angiography in cerebrovascular neurosurgery can drive the repositioning or addition of aneurysm clips. Our institution has switched from a strategy of intraoperative digital subtraction angiography (DSA) universally, to a strategy of indocyanine green (ICG) videoangiography with DSA on an as-needed basis. We retrospectively evaluated whether the rates of perioperative stroke, unexpected postoperative aneurysm residual, or parent vessel stenosis differed in 100 patients from each era (2002, "DSA era"; 2007, "ICG era"). The clip repositioning rate for neck residual or parent vessel stenosis did not differ significantly between the two eras. There were no differences in the rate of perioperative stroke or rate of false-negative studies. The per-patient cost of intraoperative imaging within the DSA era was significantly higher than in the ICG era. The replacement of routine intraoperative DSA with ICG videoangiography and selective intraoperative DSA in cerebrovascular aneurysm surgery is safe and effective. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Optical critical dimension metrology for directed self-assembly assisted contact hole shrink

NASA Astrophysics Data System (ADS)

Dixit, Dhairya; Green, Avery; Hosler, Erik R.; Kamineni, Vimal; Preil, Moshe E.; Keller, Nick; Race, Joseph; Chun, Jun Sung; O'Sullivan, Michael; Khare, Prasanna; Montgomery, Warren; Diebold, Alain C.

2016-01-01

Directed self-assembly (DSA) is a potential patterning solution for future generations of integrated circuits. Its main advantages are high pattern resolution (˜10 nm), high throughput, no requirement of high-resolution mask, and compatibility with standard fab-equipment and processes. The application of Mueller matrix (MM) spectroscopic ellipsometry-based scatterometry to optically characterize DSA patterned contact hole structures fabricated with phase-separated polystyrene-b-polymethylmethacrylate (PS-b-PMMA) is described. A regression-based approach is used to calculate the guide critical dimension (CD), DSA CD, height of the PS column, thicknesses of underlying layers, and contact edge roughness of the post PMMA etch DSA contact hole sample. Scanning electron microscopy and imaging analysis is conducted as a comparative metric for scatterometry. In addition, optical model-based simulations are used to investigate MM elements' sensitivity to various DSA-based contact hole structures, predict sensitivity to dimensional changes, and its limits to characterize DSA-induced defects, such as hole placement inaccuracy, missing vias, and profile inaccuracy of the PMMA cylinder.

High Voltage Magnesium-ion Battery Enabled by Nanocluster Mg3Bi2 Alloy Anode in Noncorrosive Electrolyte.

PubMed

Tan, Yi-Hong; Yao, Wei-Tang; Zhang, Tianwen; Ma, Tao; Lu, Lei-Lei; Zhou, Fei; Yao, Hong-Bin; Yu, Shu-Hong

2018-05-03

Currently, developing high voltage (beyond 2 V) rechargeable Mg-ion batteries still remains a great challenge owing to the limit of corrosive electrolyte and low compatibility of anode material. Here we report a facile one step solid state alloying route to synthesize nanoclustered Mg 3 Bi 2 alloy as a high-performance anode to build up a 2 V Mg-ion battery using noncorrosive electrolyte. The fabricated nanoclustered Mg 3 Bi 2 anode delivers a high reversible specific capacity (360 mAh g -1 ) with excellent stability (90.7% capacity retention over 200 cycles) and high Coulombic efficiency (average 98%) at 0.1 A g -1 . The good performance is attributed to the stable nanostructures, which effectively accommodate the reversible Mg 2+ ion insertion/deinsertion without losing electric contact among clusters. Significantly, the nanoclustered Mg 3 Bi 2 anode can be coupled with high voltage cathode Prussian Blue to assemble a full cell using noncorrosive electrolyte, showing a stable cycling (88% capacity retention over 200 cycles at 0.2 A g -1 ) and good rate capability (103 mAh g -1 at 0.1 A g -1 and 58 mAh g -1 at 2 A g -1 ). The energy and power density of the as-fabricated full cell can reach up to 81 Wh kg -1 and 2850 W kg -1 , respectively, which are both the highest values among the reported Mg-ion batteries using noncorrosive electrolytes. This study demonstrates a cost-effective route to fabricate stable and high voltage rechargeable Mg-ion battery potentially for grid-scale energy storage.

SAR Observation and Numerical Simulation of Internal Solitary Wave Refraction and Reconnection Behind the Dongsha Atoll

NASA Astrophysics Data System (ADS)

Jia, T.; Liang, J. J.; Li, X.-M.; Sha, J.

2018-01-01

The refraction and reconnection of internal solitary waves (ISWs) around the Dongsha Atoll (DSA) in the northern South China Sea (SCS) are investigated based on spaceborne synthetic aperture radar (SAR) observations and numerical simulations. In general, a long ISW front propagating from the deep basin of the northern SCS splits into northern and southern branches when it passes the DSA. In this study, the statistics of Envisat Advanced SAR (ASAR) images show that the northern and southern wave branches can reconnect behind the DSA, but the reconnection location varies. A previously developed nonlinear refraction model is set up to simulate the refraction and reconnection of the ISWs behind the DSA, and the model is used to evaluate the effects of ocean stratification, background currents, and incoming ISW characteristics at the DSA on the variation in reconnection locations. The results of the first realistic simulation agree with consecutive TerraSAR-X (TSX) images captured within 12 h of each other. Further sensitivity simulations show that ocean stratification, background currents, and initial wave amplitudes all affect the phase speeds of wave branches and therefore shift their reconnection locations while shapes and locations of incoming wave branches upstream of the DSA profoundly influence the subsequent propagation paths. This study clarifies the variation in reconnection locations of ISWs downstream of the DSA and reveals the important mechanisms governing the reconnection process, which can improve our understanding of the propagation of ISWs near the DSA.

The Influence of Immunosuppressive Agents on the Risk of De Novo Donor-Specific HLA Antibody Production in Solid Organ Transplant Recipients

PubMed Central

O'Leary, Jacqueline G.; Samaniego, Millie; Barrio, Marta Crespo; Potena, Luciano; Zeevi, Adriana; Djamali, Arjang; Cozzi, Emanuele

2016-01-01

Production of de novo donor-specific antibodies (dnDSA) is a major risk factor for acute and chronic antibody-mediated rejection and graft loss after all solid organ transplantation. In this article, we review the data available on the risk of individual immunosuppressive agents and their ability to prevent dnDSA production. Induction therapy with rabbit antithymocyte globulin may achieve a short-term decrease in dnDSA production in moderately sensitized patients. Rituximab induction may be beneficial in sensitized patients, and in abrogating rebound antibody response in patients undergoing desensitization or treatment for antibody-mediated rejection. Use of bortezomib for induction therapy in at-risk patients is of interest, but the benefits are unproven. In maintenance regimens, nonadherent and previously sensitized patients are not suitable for aggressive weaning protocols, particularly early calcineurin inhibitor withdrawal without lymphocyte-depleting induction. Early conversion to mammalian target of rapamycin inhibitor monotherapy has been reported to increase the risk of dnDSA formation, but a combination of mammalian target of rapamycin inhibitor and reduced-exposure calcineurin inhibitor does not appear to alter the risk. Early steroid therapy withdrawal in standard-risk patients after induction has no known dnDSA penalty. The available data do not demonstrate a consistent effect of mycophenolic acid on dnDSA production. Risk minimization for dnDSA requires monitoring of adherence, appropriate risk stratification, risk-based immunosuppression intensity, and prospective DSA surveillance. PMID:26680372

Computed tomography versus digital subtraction angiography for the diagnosis of obscure gastrointestinal bleeding.

PubMed

Wildgruber, Moritz; Wrede, Christian E; Zorger, Niels; Müller-Wille, René; Hamer, Okka W; Zeman, Florian; Stroszczynski, Christian; Heiss, Peter

2017-03-01

The diagnostic yield of computed tomography angiography (CTA) compared to digital subtraction angiography (DSA) for major obscure gastrointestinal bleeding (OGIB) is not known. Aim of the study was to prospectively evaluate the diagnostic yield of CTA versus DSA for the diagnosis of major OGIB. The institutional review board approved the study and informed consent was obtained from each patient. Patients with major OGIB were prospectively enrolled to undergo both CTA and DSA. Two blinded radiologists each reviewed the CTA and DSA images retrospectively and independently. Contrast material extravasation into the gastrointestinal lumen was considered diagnostic for active bleeding. Primary end point of the study was the diagnostic yield, defined as the frequency a technique identified an active bleeding or a potential bleeding lesion. The diagnostic yield of CTA and DSA were compared by McNemar's test. 24 consecutive patients (11 men; median age 64 years) were included. CTA and DSA identified an active bleeding or a potential bleeding lesion in 92% (22 of 24 patients; 95% CI 72%-99%) and 29% (7 of 24 patients; 95% CI 12%-49%) of patients, respectively (p<0.001). CTA and DSA identified an active bleeding in 42% (10 of 24; 95% CI 22%-63%) and 21% (5 of 24; 95% CI 7%-42%) of patients, respectively (p=0.06). Due to the lower invasiveness and higher diagnostic yield CTA should be favored over DSA for the diagnosis of major OGIB. Copyright © 2016. Published by Elsevier B.V.

MultiLayer solid electrolyte for lithium thin film batteries

DOEpatents

Lee, Se -Hee; Tracy, C. Edwin; Pitts, John Roland; Liu, Ping

2015-07-28

A lithium metal thin-film battery composite structure is provided that includes a combination of a thin, stable, solid electrolyte layer [18] such as Lipon, designed in use to be in contact with a lithium metal anode layer; and a rapid-deposit solid electrolyte layer [16] such as LiAlF.sub.4 in contact with the thin, stable, solid electrolyte layer [18]. Batteries made up of or containing these structures are more efficient to produce than other lithium metal batteries that use only a single solid electrolyte. They are also more resistant to stress and strain than batteries made using layers of only the stable, solid electrolyte materials. Furthermore, lithium anode batteries as disclosed herein are useful as rechargeable batteries.

Surface treatments for aluminium alloys

NASA Astrophysics Data System (ADS)

Ardelean, M.; Lascău, S.; Ardelean, E.; Josan, A.

2018-01-01

Typically, in contact with the atmosphere, the aluminium surface is covered with an aluminium oxide layer, with a thickness of less than 1-2μm. Due to its low thickness, high porosity and low mechanical strength, this layer does not protect the metal from corrosion. Anodizing for protective and decorative purposes is the most common method of superficial oxidation processes and is carried out through anodic oxidation. The oxide films, resulted from anodizing, are porous, have a thickness of 20-50μm, and are heat-resistant, stable to water vapour and other corrosion agents. Hard anodizing complies with the same obtains principles as well as decorative and protective anodization. The difference is in that hard anodizing is achieved at low temperatures and high intensity of electric current. In the paper are presented the results of decorative and hard anodization for specimens made from several aluminium alloys in terms of the appearance of the specimens and of the thickness of the anodized.

Improved cost-effectiveness of the block co-polymer anneal process for DSA

NASA Astrophysics Data System (ADS)

Pathangi, Hari; Stokhof, Maarten; Knaepen, Werner; Vaid, Varun; Mallik, Arindam; Chan, Boon Teik; Vandenbroeck, Nadia; Maes, Jan Willem; Gronheid, Roel

2016-04-01

This manuscript first presents a cost model to compare the cost of ownership of DSA and SAQP for a typical front end of line (FEoL) line patterning exercise. Then, we proceed to a feasibility study of using a vertical furnace to batch anneal the block co-polymer for DSA applications. We show that the defect performance of such a batch anneal process is comparable to the process of record anneal methods. This helps in increasing the cost benefit for DSA compared to the conventional multiple patterning approaches.

Alloantibodies in Organ Transplant: A Review of Data Published in 2015.

PubMed

Maehara, Curtis; Everly, Matthew J

2015-01-01

In recent years, there have been multiple studies published on longitudinal and retrospective analysis of anti-human leukocyte antigen (anti-HLA) antibodies. The focus of these reports was to determine specific characteristics of the impact of donor specific anti-HLA antibodies (DSA) in organ transplantation. There has been a growing concern about DSA in a multitude of organ transplants. Research efforts are attempting to gain a better understanding of DSA and possible treatment implications for patients with DSA. In 2015, many studies confirm and expand upon both the understanding of the humoral theory and the clinical applications of DSA in transplantation. This review highlights some of these publications and their contributions to the humoral theory of transplantation. Copyright© 2016 by the Terasaki Foundation Laboratory.

Anode-Free Rechargeable Lithium Metal Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Jiangfeng; Adams, Brian D.; Zheng, Jianming

2016-08-18

Anode-free rechargeable lithium (Li) batteries (AFLBs) are phenomenal energy storage systems due to their significantly increased energy density and reduced cost relative to Li-ion batteries, as well as ease of assembly owing to the absence of an active (reactive) anode material. However, significant challenges, including Li dendrite growth and low cycling Coulombic efficiency (CE), have prevented their practical implementation. Here, we report for the first time an anode-free rechargeable lithium battery based on a Cu||LiFePO4 cell structure with an extremely high CE (> 99.8%). This results from the utilization of both an exceptionally stable electrolyte and optimized charge/discharge protocols whichmore » minimize the corrosion of the in-situ formed Li metal anode.« less

Improvement of corrosion resistance of NiTi sputtered thin films by anodization

NASA Astrophysics Data System (ADS)

Bayat, N.; Sanjabi, S.; Barber, Z. H.

2011-08-01

Anodization of sputtered NiTi thin films has been studied in 1 M acetic acid at 23 °C for different voltages from 2 to 10 V. The morphology and cross-sectional structures of the untreated and anodized surfaces were investigated by field emission scanning electron microscopy (FE-SEM). The results show that increasing anodization voltage leads to film surface roughening and unevenness. It can be seen that the thickness of the anodized layer formed on the NiTi surface is in the nanometer range. The corrosion resistance of anodized thin films was studied by potentiodynamic scan (PDS) and impedance spectroscopy (EIS) techniques in Hank's solution at 310 K (37 °C). It was shown that the corrosion resistance of the anodized film surface improved with increasing voltage to 6 V. Anodization of austenitic sputtered NiTi thin films has also been studied, in the same anodizing conditions, at 4 V. Comparison of anodized sputtered NiTi thin films with anodized austenitic shape memory films illustrate that the former are more corrosion resistant than the latter after 1 h immersion in Hank's solution, which is attributed to the higher grain boundary density to quickly form a stable and protective passive film.

Process for forming sulfuric acid

DOEpatents

Lu, Wen-Tong P.

1981-01-01

An improved electrode is disclosed for the anode in a sulfur cycle hydrogen generation process where sulfur dioxie is oxidized to form sulfuric acid at the anode. The active compound in the electrode is palladium, palladium oxide, an alloy of palladium, or a mixture thereof. The active compound may be deposited on a porous, stable, conductive substrate.

Lithium-coated polymeric matrix as a minimum volume-change and dendrite-free lithium metal anode

PubMed Central

Liu, Yayuan; Lin, Dingchang; Liang, Zheng; Zhao, Jie; Yan, Kai; Cui, Yi

2016-01-01

Lithium metal is the ideal anode for the next generation of high-energy-density batteries. Nevertheless, dendrite growth, side reactions and infinite relative volume change have prevented it from practical applications. Here, we demonstrate a promising metallic lithium anode design by infusing molten lithium into a polymeric matrix. The electrospun polyimide employed is stable against highly reactive molten lithium and, via a conformal layer of zinc oxide coating to render the surface lithiophilic, molten lithium can be drawn into the matrix, affording a nano-porous lithium electrode. Importantly, the polymeric backbone enables uniform lithium stripping/plating, which successfully confines lithium within the matrix, realizing minimum volume change and effective dendrite suppression. The porous electrode reduces the effective current density; thus, flat voltage profiles and stable cycling of more than 100 cycles is achieved even at a high current density of 5 mA cm−2 in both carbonate and ether electrolyte. The advantages of the porous, polymeric matrix provide important insights into the design principles of lithium metal anodes. PMID:26987481

Universal quinone electrodes for long cycle life aqueous rechargeable batteries

NASA Astrophysics Data System (ADS)

Liang, Yanliang; Jing, Yan; Gheytani, Saman; Lee, Kuan-Yi; Liu, Ping; Facchetti, Antonio; Yao, Yan

2017-08-01

Aqueous rechargeable batteries provide the safety, robustness, affordability, and environmental friendliness necessary for grid storage and electric vehicle operations, but their adoption is plagued by poor cycle life due to the structural and chemical instability of the anode materials. Here we report quinones as stable anode materials by exploiting their structurally stable ion-coordination charge storage mechanism and chemical inertness towards aqueous electrolytes. Upon rational selection/design of quinone structures, we demonstrate three systems that coupled with industrially established cathodes and electrolytes exhibit long cycle life (up to 3,000 cycles/3,500 h), fast kinetics (>=20C), high anode specific capacity (up to 200-395 mAh g-1), and several examples of state-of-the-art specific energy/energy density (up to 76-92 Wh kg-1/ 161-208 Wh l-1) for several operational pH values (-1 to 15), charge carrier species (H+, Li+, Na+, K+, Mg2+), temperature (-35 to 25 °C), and atmosphere (with/without O2), making them a universal anode approach for any aqueous battery technology.

Lithium-coated polymeric matrix as a minimum volume-change and dendrite-free lithium metal anode

DOE PAGES

Liu, Yayuan; Lin, Dingchang; Liang, Zheng; ...

2016-03-18

Lithium metal is the ideal anode for the next generation of high-energy-density batteries. Nevertheless, dendrite growth, side reactions and infinite relative volume change have prevented it from practical applications. Here, we demonstrate a promising metallic lithium anode design by infusing molten lithium into a polymeric matrix. The electrospun polyimide employed is stable against highly reactive molten lithium and, via a conformal layer of zinc oxide coating to render the surface lithiophilic, molten lithium can be drawn into the matrix, affording a nano-porous lithium electrode. Importantly, the polymeric backbone enables uniform lithium stripping/plating, which successfully confines lithium within the matrix, realizingmore » minimum volume change and effective dendrite suppression. The porous electrode reduces the effective current density; thus, flat voltage profiles and stable cycling of more than 100 cycles is achieved even at a high current density of 5 mA cm -2 in both carbonate and ether electrolyte. Furthermore, the advantages of the porous, polymeric matrix provide important insights into the design principles of lithium metal anodes.« less

Lithium-coated polymeric matrix as a minimum volume-change and dendrite-free lithium metal anode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yayuan; Lin, Dingchang; Liang, Zheng

Lithium metal is the ideal anode for the next generation of high-energy-density batteries. Nevertheless, dendrite growth, side reactions and infinite relative volume change have prevented it from practical applications. Here, we demonstrate a promising metallic lithium anode design by infusing molten lithium into a polymeric matrix. The electrospun polyimide employed is stable against highly reactive molten lithium and, via a conformal layer of zinc oxide coating to render the surface lithiophilic, molten lithium can be drawn into the matrix, affording a nano-porous lithium electrode. Importantly, the polymeric backbone enables uniform lithium stripping/plating, which successfully confines lithium within the matrix, realizingmore » minimum volume change and effective dendrite suppression. The porous electrode reduces the effective current density; thus, flat voltage profiles and stable cycling of more than 100 cycles is achieved even at a high current density of 5 mA cm -2 in both carbonate and ether electrolyte. Furthermore, the advantages of the porous, polymeric matrix provide important insights into the design principles of lithium metal anodes.« less

In situ analysis of capacity fade in thin-film anodes for high performance Li-ion all-solid-state batteries

NASA Astrophysics Data System (ADS)

Leite, Marina S.; Gong, Chen; Ruzmetov, Dmitry; Talin, A. Alec

There is still a pressing need to understand how the solid-interfaces in Li-ion all-solid-batteries form, including their chemical composition and electrical characteristics. In order to resolve the origin of the degradation mechanism in Al anodes, we combine in situ scanning electron microscopy in ultra-high vacuum with electrochemical cycling, in addition to ex situ characterization of the morphological, chemical, and electrical changes of the Al anodes upon lithiation. An AlLi alloy capped by a stable Al-Li-O is formed on the top surface of the anode, trapping Li, which results in the capacity fade, from 48.0 to 41.5 μ.Ah/cm2 in two cycles. The addition of a Cu capping layer is insufficient to prevent the device degradation because of the fast Li diffusion within Al. Yet, Si present extremely stable cycling: >92% of capacity retention after 100 cycles, with average Coulombic efficiency of 98%. Our in situ measurements represent a new platform for probing the real-time degradation of electrodes in all-solid-state batteries for energy storage devices.

Stable synthesis of few-layered boron nitride nanotubes by anodic arc discharge.

PubMed

Yeh, Yao-Wen; Raitses, Yevgeny; Koel, Bruce E; Yao, Nan

2017-06-08

Boron nitride nanotubes (BNNTs) were successfully synthesized by a dc arc discharge using a boron-rich anode as synthesis feedstock in a nitrogen gas environment at near atmospheric pressure. The synthesis was achieved independent of the cathode material suggesting that under such conditions the arc operates in so-called anodic mode with the anode material being consumed by evaporation due to the arc heating. To sustain the arc current by thermionic electron emission, the cathode has to be at sufficiently high temperature, which for a typical arc current density of ~100 A/cm 2 , is above the boron melting point (2350 K). With both electrodes made from the same boron-rich alloy, we found that the arc operation unstable due to frequent sticking between two molten electrodes and formation of molten droplets. Stable and reliable arc operation and arc synthesis were achieved with the boron-rich anode and the cathode made from a refractory metal which has a melting temperature above the melting point of boron. Ex-situ characterization of synthesized BNNTs with electron microscopy and Raman spectroscopy revealed that independent of the cathode material, the tubes are primarily single and double walled. The results also show evidence of root-growth of BNNTs produced in the arc discharge.

Stable synthesis of few-layered boron nitride nanotubes by anodic arc discharge

DOE PAGES

Yeh, Yao-Wen; Raitses, Yevgeny; Koel, Bruce E.; ...

2017-06-08

Boron nitride nanotubes (BNNTs) were successfully synthesized by a dc arc discharge using a boron-rich anode as synthesis feedstock in a nitrogen gas environment at near atmospheric pressure. The synthesis was achieved independent of the cathode material suggesting that under such conditions the arc operates in so-called anodic mode with the anode material being consumed by evaporation due to the arc heating. In order to sustain the arc current by thermionic electron emission, the cathode has to be at sufficiently high temperature, which for a typical arc current density of similar to 100 A/cm 2, is above the boron meltingmore » point (2350 K). With both electrodes made from the same boron-rich alloy, we found that the arc operation unstable due to frequent sticking between two molten electrodes and formation of molten droplets. We achieved a stable and reliable arc operation and arc synthesis with the boronrich anode and the cathode made from a refractory metal which has a melting temperature above the melting point of boron. Ex-situ characterization of synthesized BNNTs with electron microscopy and Raman spectroscopy revealed that independent of the cathode material, the tubes are primarily single and double walled. Our results also show evidence of root-growth of BNNTs produced in the arc discharge.« less

Stable synthesis of few-layered boron nitride nanotubes by anodic arc discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeh, Yao-Wen; Raitses, Yevgeny; Koel, Bruce E.

Boron nitride nanotubes (BNNTs) were successfully synthesized by a dc arc discharge using a boron-rich anode as synthesis feedstock in a nitrogen gas environment at near atmospheric pressure. The synthesis was achieved independent of the cathode material suggesting that under such conditions the arc operates in so-called anodic mode with the anode material being consumed by evaporation due to the arc heating. In order to sustain the arc current by thermionic electron emission, the cathode has to be at sufficiently high temperature, which for a typical arc current density of similar to 100 A/cm 2, is above the boron meltingmore » point (2350 K). With both electrodes made from the same boron-rich alloy, we found that the arc operation unstable due to frequent sticking between two molten electrodes and formation of molten droplets. We achieved a stable and reliable arc operation and arc synthesis with the boronrich anode and the cathode made from a refractory metal which has a melting temperature above the melting point of boron. Ex-situ characterization of synthesized BNNTs with electron microscopy and Raman spectroscopy revealed that independent of the cathode material, the tubes are primarily single and double walled. Our results also show evidence of root-growth of BNNTs produced in the arc discharge.« less

Optical Metrology for Directed Self-assembly Patterning Using Mueller Matrix Spectroscopic Ellipsometry Based Scatterometry

NASA Astrophysics Data System (ADS)

Dixit, Dhairya J.

The semiconductor industry continues to drive patterning solutions that enable devices with higher memory storage capacity, faster computing performance, lower cost per transistors, and higher transistor density. These developments in the field of semiconductor manufacturing along with the overall minimization of the size of transistors require cutting-edge metrology tools for characterization. Directed self-assembly (DSA) patterning process can be used to fabricate nanoscale line-space patterns and contact holes via thermodynamically driven micro-phase separation of block copolymer (BCP) films with boundary constraints from guiding templates. Its main advantages are high pattern resolution (~10 nm), high throughput, no requirement of a high-resolution mask, and compatibility with standard fab-equipment and processes. Although research into DSA patterning has demonstrated a high potential as a nanoscale patterning process, there are critical challenges that must be overcome before transferring DSA into high volume manufacturing, including achievement of low defect density and high process stability. For this, advances in critical dimension (CD) and overlay measurement as well as rapid defect characterization are required. Both scatterometry and critical dimension-scanning electron microscopy (CD-SEM) are routinely used for inline dimensional metrology. CD-SEM inspection is limited, as it does not easily provide detailed line-shape information, whereas scatterometry has the capability of measuring important feature dimensions including: line-width, line-shape, sidewall-angle, and thickness of the patterned samples quickly and non-destructively. The present work describes the application of Mueller matrix spectroscopic ellipsometry (MMSE) based scatterometry to optically characterize DSA patterned line- space grating and contact hole structures fabricated with phase-separated polystyrene-b-polymethylmethacrylate (PS-b-PMMA) at various integration steps of BCP DSA based patterning process. This work focuses on understanding the efficacy of MMSE base scatterometry for characterizing complex DSA structures. For example, the use of symmetry-antisymmetry properties associated with Mueller matrix (MM) elements to understand the topography of the periodic nanostructures and measure defectivity. Simulations (the forward problem approach of scatterometry) are used to investigate MM elements' sensitivity to changes in DSA structure such as one vs. two contact hole patterns and predict sensitivity to dimensional changes. A regression-based approach is used to extract feature shape parameters of the DSA structures by fitting simulated optical spectra to experimental optical spectra. Detection of the DSA defects is a key to reducing defect density for eventual manufacturability and production use of DSA process. Simulations of optical models of structures containing defects are used to evaluate the sensitivity of MM elements to DSA defects. This study describes the application of MMSE to determine the DSA pattern defectivity via spectral comparisons based on optical anisotropy and depolarization. The use of depolarization and optical anisotropy for characterization of experimental MMSE data is a very recent development in scatterometry. In addition, reconstructed scatterometry models are used to calculate line edge roughness in 28 nm pitch Si fins fabricated using DSA patterning process.

The Effects of a Dynamic Spectrum Access Overlay in LTE-Advanced Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Juan D. Deaton; Ryan E. lrwin; Luiz A. DaSilva

As early as 2014, wireless network operators spectral capacity will be overwhelmed by a data tsunami brought on by new devices and applications. To augment spectral capacity, operators could deploy a Dynamic Spectrum Access (DSA) overlay. In the light of the many planned Long Term Evolution (LTE) network deployments, the affects of a DSA overlay have not been fully considered into the existing LTE standards. Coalescing many different aspects of DSA, this paper develops the Spectrum Accountability (SA) framework. The SA framework defines specific network element functionality, protocol interfaces, and signaling flow diagrams for LTE to support service requests andmore » enforce rights of responsibilities of primary and secondary users, respectively. We also include a network simulation to quantify the benefits of using DSA channels to augment capacity. Based on our simulation we show that, network operators can benefit up to %40 increase in operating capacity when sharing DSA bands to augment spectral capacity. With our framework, this paper could serve as an guide in developing future LTE network standards that include DSA.« less

The European Society for Blood and Marrow Transplantation (EBMT) Consensus Guidelines for the Detection and Treatment of Donor-specific Anti-HLA Antibodies (DSA) in Haploidentical Hematopoietic Cell Transplantation.

PubMed

Ciurea, Stefan O; Cao, Kai; Fernadez-Vina, Marcelo; Kongtim, Piyanuch; Malki, Monzr Al; Fuchs, Ephraim; Luznik, Leo; Huang, Xiao-Jun; Ciceri, Fabio; Locatelli, Franco; Aversa, Franco; Castagna, Luca; Bacigalupo, Andrea; Martelli, Massimo; Blaise, Didier; Handgretinger, Rupert; Roy, Denis-Claude; O'Donnell, Paul; Bashey, Asad; Lazarus, Hillard M; Ballen, Karen; Savani, Bipin N; Mohty, Mohamad; Nagler, Arnon

2018-05-01

Haploidentical donors are now increasingly considered for transplantation in the absence of HLA-matched donors or when an urgent transplant is needed. Donor-specific anti-HLA antibodies (DSA) have been recently recognized as an important barrier against successful engraftment of donor cells, which can affect transplant survival. DSA appear more prevalent in this type of transplant due to higher likelihood of alloimmunization of multiparous females against offspring's HLA antigens, and the degree of mismatch. Here we summarize the evidence for the role of DSA in the development of primary graft failure in haploidentical transplantation and provide consensus recommendations from the European Society for Blood and Marrow Transplant Group on testing, monitoring, and treatment of patients with DSA receiving haploidentical hematopoietic progenitor cell transplantation.

Comparison of C-arm Computed Tomography and Digital Subtraction Angiography in Patients with Chronic Thromboembolic Pulmonary Hypertension

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinrichs, Jan B., E-mail: hinrichs.jan@mh-hannover.de; Marquardt, Steffen, E-mail: marquardt.steffen@mh-hannover.de; Falck, Christian von, E-mail: falck.christian.von@mh-hannover.de

PurposeTo assess the feasibility and diagnostic performance of contrast-enhanced, C-arm computed tomography (CACT) of the pulmonary arteries compared to digital subtraction angiography (DSA) in patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH).MaterialsFifty-two patients with CTEPH underwent ECG-gated DSA and contrast-enhanced CACT. Two readers (R1, R2) independently evaluated pulmonary artery segments and their sub-segmental branching using DSA and CACT for optimal image quality. Afterwards, the diagnostic findings, i.e., intraluminal filling defects, stenosis, and occlusion, were compared. Inter-modality and inter-observer agreement was calculated, and subsequently consensus reading was done and correlated to a reference standard representing the overall consensus of both modalities.more » Fisher’s exact test and Cohen’s Kappa were applied.ResultsA total of 1352 pulmonary segments were evaluated, of which 1255 (92.8 %) on DSA and 1256 (92.9 %) on CACT were rated to be fully diagnostic. The main causes of the non-diagnostic image quality were motion artifacts on CACT (R1:37, R2:78) and insufficient contrast enhancement on DSA (R1:59, R2:38). Inter-observer agreement was good for DSA (κ = 0.74) and CACT (κ = 0.75), while inter-modality agreement was moderate (R1: κ = 0.46, R2: κ = 0.47). Compared to the reference standard, the inter-modality agreement for CACT was excellent (κ = 0.96), whereas it was inferior for DSA (κ = 0.61) due to the higher number of abnormal consensus findings read as normal on DSA.ConclusionCACT of the pulmonary arteries is feasible and provides additional information to DSA. CACT has the potential to improve the diagnostic work-up of patients with CTEPH and may be particularly useful prior to surgical or interventional treatment.« less

Electrochemical separation and concentration of hydrogen sulfide from gas mixtures

DOEpatents

Winnick, Jack; Sather, Norman F.; Huang, Hann S.

1984-10-30

A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

ELECTROCHEMICAL SEPARATION AND CONCENTRATION OF HYDROGEN SULFIDE FROM GAS MIXTURES

DOEpatents

Winnick, Jack; Sather, Norman F.; Huang, Hann S.

1984-10-30

A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

Electrochemical separation and concentration of sulfur containing gases from gas mixtures

DOEpatents

Winnick, Jack

1981-01-01

A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4.sup.= or, in the case of H.sub.2 S, to S.sup.=. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

Interphase Evolution of a Lithium-Ion/Oxygen Battery.

PubMed

Elia, Giuseppe Antonio; Bresser, Dominic; Reiter, Jakub; Oberhumer, Philipp; Sun, Yang-Kook; Scrosati, Bruno; Passerini, Stefano; Hassoun, Jusef

2015-10-14

A novel lithium-ion/oxygen battery employing Pyr14TFSI-LiTFSI as the electrolyte and nanostructured LixSn-C as the anode is reported. The remarkable energy content of the oxygen cathode, the replacement of the lithium metal anode by a nanostructured stable lithium-alloying composite, and the concomitant use of nonflammable ionic liquid-based electrolyte result in a new and intrinsically safer energy storage system. The lithium-ion/oxygen battery delivers a stable capacity of 500 mAh g(-1) at a working voltage of 2.4 V with a low charge-discharge polarization. However, further characterization of this new system by electrochemical impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy reveals the progressive decrease of the battery working voltage, because of the crossover of oxygen through the electrolyte and its direct reaction with the LixSn-C anode.

Polyethylene oxide film coating enhances lithium cycling efficiency of an anode-free lithium-metal battery.

PubMed

Assegie, Addisu Alemayehu; Cheng, Ju-Hsiang; Kuo, Li-Ming; Su, Wei-Nien; Hwang, Bing-Joe

2018-03-29

The practical implementation of an anode-free lithium-metal battery with promising high capacity is hampered by dendrite formation and low coulombic efficiency. Most notably, these challenges stem from non-uniform lithium plating and unstable SEI layer formation on the bare copper electrode. Herein, we revealed the homogeneous deposition of lithium and effective suppression of dendrite formation using a copper electrode coated with a polyethylene oxide (PEO) film in an electrolyte comprising 1 M LiTFSI, DME/DOL (1/1, v/v) and 2 wt% LiNO3. More importantly, the PEO film coating promoted the formation of a thin and robust SEI layer film by hosting lithium and regulating the inevitable reaction of lithium with the electrolyte. The modified electrode exhibited stable cycling of lithium with an average coulombic efficiency of ∼100% over 200 cycles and low voltage hysteresis (∼30 mV) at a current density of 0.5 mA cm-2. Moreover, we tested the anode-free battery experimentally by integrating it with an LiFePO4 cathode into a full-cell configuration (Cu@PEO/LiFePO4). The new cell demonstrated stable cycling with an average coulombic efficiency of 98.6% and capacity retention of 30% in the 200th cycle at a rate of 0.2C. These impressive enhancements in cycle life and capacity retention result from the synergy of the PEO film coating, high electrode-electrolyte interface compatibility, stable polar oligomer formation from the reduction of 1,3-dioxolane and the generation of SEI-stabilizing nitrite and nitride upon lithium nitrate reduction. Our result opens up a new route to realize anode-free batteries by modifying the copper anode with PEO to achieve ever more demanding yet safe interfacial chemistry and control of dendrite formation.

Four-dimensional computed tomography angiographic evaluation of cranial dural arteriovenous fistula before and after embolization.

PubMed

Tian, Bing; Xu, Bing; Lu, Jianping; Liu, Qi; Wang, Li; Wang, Minjie

2015-06-01

This study aimed to evaluate the usefulness of four-dimensional CTA before and after embolization treatment with ONYX-18 in eleven patients with cranial dural arteriovenous fistulas, and to compare the results with those of the reference standard DSA. Eleven patients with cranial dural arteriovenous fistulas detected on DSA underwent transarterial embolization with ONYX-18. Four-dimensional CTA was performed an average of 2 days before and 4 days after DSA. Four-dimensional CTA and DSA images were reviewed by two neuroradiologists for identification of feeding arteries and drainage veins and for determining treatment effects. Interobserver and intermodality agreement between four-dimensional CTA and DSA were assessed. Forty-two feeding arteries were identified for 14 fistulas in the 11 patients. Of these, 36 (85.71%) were detected on four-dimensional CTA. After transarterial embolization, one patient got partly embolized, and the fistulas in the remaining 10 patients were completely occluded. The interobserver agreement for four-dimensional CTA and intermodality agreement between four-dimensional CTA and DSA were excellent (κ=1) for shunt location, identification of drainage veins, and fistula occlusion after treatment. Four-dimensional CTA images are highly accurate when compared with DSA images both before and after transarterial embolization treatment. Four-dimensional CTA can be used for diagnosis as well as follow-up of cranial dural arteriovenous fistulas in clinical settings. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

A Modified Mechanical Threshold Stress Constitutive Model for Austenitic Stainless Steels

NASA Astrophysics Data System (ADS)

Prasad, K. Sajun; Gupta, Amit Kumar; Singh, Yashjeet; Singh, Swadesh Kumar

2016-12-01

This paper presents a modified mechanical threshold stress (m-MTS) constitutive model. The m-MTS model incorporates variable athermal and dynamic strain aging (DSA) Components to accurately predict the flow stress behavior of austenitic stainless steels (ASS)-316 and 304. Under strain rate variations between 0.01-0.0001 s-1, uniaxial tensile tests were conducted at temperatures ranging from 50-650 °C to evaluate the material constants of constitutive models. The test results revealed the high dependence of flow stress on strain, strain rate and temperature. In addition, it was observed that DSA occurred at elevated temperatures and very low strain rates, causing an increase in flow stress. While the original MTS model is capable of predicting the flow stress behavior for ASS, statistical parameters point out the inefficiency of the model when compared to other models such as Johnson Cook model, modified Zerilli-Armstrong (m-ZA) model, and modified Arrhenius-type equations (m-Arr). Therefore, in order to accurately model both the DSA and non-DSA regimes, the original MTS model was modified by incorporating variable athermal and DSA components. The suitability of the m-MTS model was assessed by comparing the statistical parameters. It was observed that the m-MTS model was highly accurate for the DSA regime when compared to the existing models. However, models like m-ZA and m-Arr showed better results for the non-DSA regime.

High risk of graft failure in patients with anti-HLA antibodies undergoing haploidentical stem-cell transplantation.

PubMed

Ciurea, Stefan O; de Lima, Marcos; Cano, Pedro; Korbling, Martin; Giralt, Sergio; Shpall, Elizabeth J; Wang, Xuemei; Thall, Peter F; Champlin, Richard E; Fernandez-Vina, Marcelo

2009-10-27

BACKGROUND.: Although donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) have been implicated in graft rejection in solid organ transplantation, their role in hematopoietic stem-cell transplantation remains unclear. METHODS.: To address the hypothesis that the presence of DSA contributes to the development graft failure, we tested 24 consecutive patients for the presence of anti-HLA antibodies determined by a sensitive and specific solid-phase/single-antigen assay. The study included a total of 28 haploidentical transplants, each with 2 to 5 HLA allele mismatches, at a single institution, from September 2005 to August 2008. RESULTS.: DSA were detected in five patients (21%). Three of four (75%) patients with DSA before the first transplant failed to engraft, compared with 1 of 20 (5%) without DSA (P=0.008). All four patients who experienced primary graft failure had second haploidentical transplants. One patient developed a second graft failure with persistent high DSA levels, whereas three engrafted, two of them in the absence of DSA. No other known factors that could negatively influence engraftment were associated with the development of graft failure in these patients. CONCLUSIONS.: These results suggest that donor-specific anti-HLA antibodies are associated with a high rate of graft rejection in patients undergoing haploidentical stem-cell transplantation. Anti-HLA sensitization should be evaluated routinely in hematopoietic stem-cell transplantation with HLA mismatched donors.

Self-organized criticality: An interplay between stable and turbulent regimes of multiple anodic double layers in glow discharge plasma

NASA Astrophysics Data System (ADS)

Alex, Prince; Carreras, Benjamin Andres; Arumugam, Saravanan; Sinha, Suraj Kumar

2018-05-01

The role of self-organized criticality (SOC) in the transformation of multiple anodic double layers (MADLs) from the stable to turbulent regime has been investigated experimentally as the system approaches towards critical behavior. The experiment was performed in a modified glow discharge plasma setup, and the initial stable state of MADL comprising three concentric perceptible layers was produced when the drift velocity of electrons towards the anode exceeds the electron thermal velocity (νd ≥ 1.3νte). The macroscopic arrangement of both positive and negative charges in opposite layers of MADL is attributed to the self-organization scenario. Beyond νd ≥ 3νte, MADL begins to collapse and approaches critical and supercritical states through layer reduction which continue till the last remaining layer of the double layer is transformed into a highly unstable radiant anode glow. The avalanche resulting from the collapse of MADL leads to the rise of turbulence in the system. Long-range correlations, a key signature of SOC, have been explored in the turbulent floating potential fluctuations using the rescaled-range analysis technique. The result shows that the existence of the self-similarity regime with self-similarity parameter H varies between 0.55 and 0.91 for time lags longer than the decorrelation time. The power law tail in the rank function, slowly decaying tail of the autocorrelation function, and 1/f behavior of the power spectra of the fluctuations are consistent with the fact that SOC plays a conclusive role in the transformation of MADL from the stable to turbulent regime. Since the existence of SOC gives a measure of complexity in the system, the result provides the condition under which complexity arises in cold plasma.

Novel microbial fuel cell design to operate with different wastewaters simultaneously.

PubMed

Mathuriya, Abhilasha Singh

2016-04-01

A novel single cathode chamber and multiple anode chamber microbial fuel cell design (MAC-MFC) was developed by incorporating multiple anode chambers into a single unit and its performance was checked. During 60 days of operation, performance of MAC-MFC was assessed and compared with standard single anode/cathode chamber microbial fuel cell (SC-MFC). The tests showed that MAC-MFC generated stable and higher power outputs compared with SC-MFC and each anode chamber contributed efficiently. Further, MAC-MFCs were incorporated with different wastewaters in different anode chambers and their behavior in MFC performance was observed. MAC-MFC efficiently treated multiple wastewaters simultaneously at low cost and small space, which claims its candidature for future possible scale-up applications. Copyright © 2015. Published by Elsevier B.V.

Gold-coated silicon nanowire-graphene core-shell composite film as a polymer binder-free anode for rechargeable lithium-ion batteries

NASA Astrophysics Data System (ADS)

Kim, Han-Jung; Lee, Sang Eon; Lee, Jihye; Jung, Joo-Yun; Lee, Eung-Sug; Choi, Jun-Hyuk; Jung, Jun-Ho; Oh, Minsub; Hyun, Seungmin; Choi, Dae-Geun

2014-07-01

We designed and fabricated a gold (Au)-coated silicon nanowires/graphene (Au-SiNWs/G) hybrid composite as a polymer binder-free anode for rechargeable lithium-ion batteries (LIBs). A large amount of SiNWs for LIB anode materials can be prepared by metal-assisted chemical etching (MaCE) process. The Au-SiNWs/G composite film on current collector was obtained by vacuum filtration using an anodic aluminum oxide (AAO) membrane and hot pressing method. Our experimental results show that the Au-SiNWs/G composite has a stable reversible capacity of about 1520 mA h/g which was maintained for 20 cycles. The Au-SiNWs/G composite anode showed much better cycling performance than SiNWs/polyvinylidene fluoride (PVDF)/Super-P, SiNWs/G composite, and pure SiNWs anodes. The improved electrochemical properties of the Au-SiNWs/G composite anode material is mainly ascribed to the composite's porous network structure.

Diffusive Shock Acceleration and Turbulent Reconnection

NASA Astrophysics Data System (ADS)

Garrel, Christian; Vlahos, Loukas; Isliker, Heinz; Pisokas, Theophilos

2018-05-01

Diffusive Shock Acceleration (DSA) cannot efficiently accelerate particles without the presence of self-consistently generated or pre-existing strong turbulence (δB/B ˜ 1) in the vicinity of the shock. The problem we address in this article is: if large amplitude magnetic disturbances are present upstream and downstream of a shock then Turbulent Reconnection (TR) will set in and will participate not only in the elastic scattering of particles but also in their heating and acceleration. We demonstrate that large amplitude magnetic disturbances and Unstable Current Sheets (UCS), spontaneously formed in the strong turbulence in the vicinity of a shock, can accelerate particles as efficiently as DSA in large scale systems and on long time scales. We start our analysis with "elastic" scatterers upstream and downstream and estimate the energy distribution of particles escaping from the shock, recovering the well known results from the DSA theory. Next we analyze the additional interaction of the particles with active scatterers (magnetic disturbances and UCS) upstream and downstream of the shock. We show that the asymptotic energy distribution of the particles accelerated by DSA/TR has very similar characteristics with the one due to DSA alone, but the synergy of DSA with TR is much more efficient: The acceleration time is an order of magnitude shorter and the maximum energy reached two orders of magnitude higher. We claim that DSA is the dominant acceleration mechanism in a short period before TR is established, and then strong turbulence will dominate the heating and acceleration of the particles. In other words, the shock serves as the mechanism to set up a strongly turbulent environment, in which the acceleration mechanism will ultimately be the synergy of DSA and TR.

Contrast-enhanced time-resolved MRA for follow-up of intracranial aneurysms treated with the pipeline embolization device.

PubMed

Boddu, S R; Tong, F C; Dehkharghani, S; Dion, J E; Saindane, A M

2014-01-01

Endovascular reconstruction and flow diversion by using the Pipeline Embolization Device is an effective treatment for complex cerebral aneurysms. Accurate noninvasive alternatives to DSA for follow-up after Pipeline Embolization Device treatment are desirable. This study evaluated the accuracy of contrast-enhanced time-resolved MRA for this purpose, hypothesizing that contrast-enhanced time-resolved MRA will be comparable with DSA and superior to 3D-TOF MRA. During a 24-month period, 37 Pipeline Embolization Device-treated intracranial aneurysms in 26 patients underwent initial follow-up by using 3D-TOF MRA, contrast-enhanced time-resolved MRA, and DSA. MRA was performed on a 1.5T unit by using 3D-TOF and time-resolved imaging of contrast kinetics. All patients underwent DSA a median of 0 days (range, 0-68) after MRA. Studies were evaluated for aneurysm occlusion, quality of visualization of the reconstructed artery, and measurable luminal diameter of the Pipeline Embolization Device, with DSA used as the reference standard. The sensitivity, specificity, and positive and negative predictive values of contrast-enhanced time-resolved MRA relative to DSA for posttreatment aneurysm occlusion were 96%, 85%, 92%, and 92%. Contrast-enhanced time-resolved MRA demonstrated superior quality of visualization (P = .0001) and a higher measurable luminal diameter (P = .0001) of the reconstructed artery compared with 3D-TOF MRA but no significant difference compared with DSA. Contrast-enhanced time-resolved MRA underestimated the luminal diameter of the reconstructed artery by 0.965 ± 0.497 mm (27% ± 13%) relative to DSA. Contrast-enhanced time-resolved MRA is a reliable noninvasive method for monitoring intracranial aneurysms following flow diversion and vessel reconstruction by using the Pipeline Embolization Device. © 2014 by American Journal of Neuroradiology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schernthaner, Ruediger Egbert; Lin, MingDe; Duran, Rafael

PurposeTo evaluate the detectability of intrahepatic cholangiocarcinoma (ICC) on dual-phase cone-beam CT (DPCBCT) during conventional transarterial chemoembolization (cTACE) compared to that of digital subtraction angiography (DSA) with respect to pre-procedure contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver.MethodsThis retrospective study included 17 consecutive patients (10 male, mean age 64) with ICC who underwent pre-procedure CE-MRI of the liver, and DSA and DPCBCT (early-arterial phase (EAP) and delayed-arterial phase (DAP)) just before cTACE. The visibility of each ICC lesion was graded by two radiologists on a three-rank scale (complete, partial, and none) on DPCBCT and DSA images, and then compared tomore » pre-procedure CE-MRI.ResultsOf 61 ICC lesions, only 45.9 % were depicted by DSA, whereas EAP- and DAP-CBCT yielded a significantly higher detectability rate of 73.8 % and 93.4 %, respectively (p < 0.01). Out of the 33 lesions missed on DSA, 18 (54.5 %) and 30 (90.9 %) were revealed on EAP- and DAP-CBCT images, respectively. DSA depicted only one lesion that was missed by DPCBCT due to streak artifacts caused by a prosthetic mitral valve. DAP-CBCT identified significantly more lesions than EAP-CBCT (p < 0.01). Conversely, EAP-CBCT did not detect lesions missed by DAP-CBCT. For complete lesion visibility, DAP-CBCT yielded significantly higher detectability (78.7 %) compared to EAP (31.1 %) and DSA (21.3 %) (p < 0.01).ConclusionDPCBCT, and especially the DAP-CBCT, significantly improved the detectability of ICC lesions during cTACE compared to DSA. We recommend the routine use of DAP-CBCT in patients with ICC for per-procedure detectability and treatment planning in the setting of TACE.« less

Perioperative Desensitization Improves Outcomes Among Crossmatch Positive Recipients of Deceased Donor Renal Transplants.

PubMed

Sharma, Amit; King, Anne; Kumar, Dhiren; Behnke, Martha; McDougan, Felecia; Kimball, Pamela M

2016-06-01

Graft failure due to chronic rejection is greater among renal transplant patients with donor-specific antibody (DSA) than among DSA-free patients. For patients dependent on deceased donor transplantation, preoperative desensitization to eliminate DSAs may be impractical. We speculated that perioperative desensitization might eliminate preexisting DSAs and prevent de novo DSAs and improve graft outcomes. We report that brief perioperative desensitization using either intravenous immunoglobulin (IVIG) or plasmapheresis/IVIG (PP/IVIG) treatment improves clinical outcomes among patients with positive crossmatches. Immediately following deceased donor transplantation, 235 renal recipients were assigned points for PRA and flow crossmatches (FCXM): delayed graft function (DGF) ≤ 1 point received standard therapy; 2 points received high-dose IVIG; and ≥3 points received PP/IVIG. The DSAs were serially monitored by single antigen bead luminex for 1 year. Five-year clinical outcomes were determined from the chart review. All desensitized patients had preoperatively positive FCXM with DSA. Rejection was more common (P < .05) among desensitized than nonsensitized groups. However, overall graft survivals were similar between the groups (P = not significant) and superior to historic untreated patients (P < .05). Treatment with PP/IVIG more effectively eliminated preexisting DSAs (67% vs 33%, P < 0.05) than IVIG, but neither regimen prevented de novo formation of DSA (20%, P = not significant). Graft survival was >90% in all desensitizated patients with DSA elimination as well as PP/IVIG patients with residual DSA. In contrast, IVIG patients with persistent DSA had poorer graft survival (45%, P < .05). Preemptive perioperative desensitization improved overall graft survival of sensitized patients compared to historic untreated patients. Plasmapheresis/IVIG had greater impact on DSA eradication and graft survival than IVIG alone. © 2016, NATCO.

The Drug Safety and Risk Management Advisory Committee: a case study of meeting frequency, content, and outcomes before and after FDAAA.

PubMed

Morrato, Elaine H; Ling, Sarah B

2012-11-01

The Food and Drug Administration Amendments Act (FDAAA) of 2007 granted FDA-expanded drug safety authority. We hypothesized that meetings involving the FDA Drug Safety and Risk Management (DSaRM) Advisory Committee might serve as a barometer for the impact of FDAAA on drug safety regulatory decision making. We conducted a case study analysis of 42 DSaRM advisory committee meetings held between 2002 and 2011. Publicly available sources (FDA meeting minutes and materials, safety alerts, and drug manufacturer Web sites) were reviewed to describe and compare DSaRM meeting frequency, content and outcomes between the pre-FDAAA (2002-2007) and post-FDAAA (2008-2011) periods. DSaRM meeting frequency increased after FDAAA (from 2.7 to 6.5 meetings per year). DSaRM meetings were more likely to be held jointly with other drug advisory committees after FDAAA (from 68% to 92% of meetings). DSaRM members were invited participants in 35 additional meetings of other drug advisory committees (2007-2011). DSaRM meetings were more likely to review issues of approvability (eg, new drugs, new indications, and new product formulations) after FDAAA. FDA questions to the committee were more likely to request an explicit drug safety assessment after FDAAA (from 31% to 76% of meetings). Content analysis of meeting outcomes and subsequent FDA regulatory decisions did not suggest a more or less risk aversive climate after FDAAA. Increased DSaRM advisory committee activity indicates its advice was being sought more broadly for drug regulatory decision making and at earlier stages of drug development after FDAAA was enacted.

Equine deep stromal abscesses (51 cases - 2004-2009)--Part 1: the clinical aspects with attention to the duration of the corneal disease, treatment history, clinical appearance, and microbiology results.

PubMed

de Linde Henriksen, Michala; Andersen, Pia H; Thomsen, Preben D; Plummer, Caryn E; Mangan, Brendan; Heegaard, Steffen; Toft, Nils; Brooks, Dennis E

2014-07-01

To study the equine deep stromal abscesses (DSA) with focus on the duration of the corneal disease, medical treatment, season of presentation, clinical appearance, and the degree of corneal vascularization. Equine DSA diagnosed, biopsied, and surgically treated at the University of Florida Veterinary Medical Center (UFVMC) from 2004 to 2009 were identified. The medical record, clinical photographic images, and microbiology results for each case were evaluated. Frequency and prevalence calculation as well as qualitative data analysis was performed for clinical and microbiological data. Fifty-one equine DSA were included in the study. Spring (March, April, May; 33.4%) and winter (December, January, February; 31.4%) were the most common seasons for DSA presentation. The 51 cases were divided into four categories of focal opacity from their clinical appearance: focal yellow (45.2%), focal white (23.5%), diffuse yellow/white (23.5%), and focal pink (7.8%). 5.9% of the DSA (n = 3) were culture positive for fungal growth, whereas 17.6% were positive for bacterial growth (n = 9). No association between short-/long-term systemically administered NSAID treatment and the corneal vascular response to the corneal lesion could be appreciated. Equine DSA most often present in the spring and winter in the subtropical environment of the state of Florida (USA). The clinical appearance may have a connection with the etiology and pathogenesis of the equine DSA. No connection between short- or long-term systemically administered NSAID and the degree of corneal vascularization of the DSA was noted. © 2013 American College of Veterinary Ophthalmologists.

Comparison of High-Resolution MR Imaging and Digital Subtraction Angiography for the Characterization and Diagnosis of Intracranial Artery Disease.

PubMed

Lee, N J; Chung, M S; Jung, S C; Kim, H S; Choi, C-G; Kim, S J; Lee, D H; Suh, D C; Kwon, S U; Kang, D-W; Kim, J S

2016-12-01

High-resolution MR imaging has recently been introduced as a promising diagnostic modality in intracranial artery disease. Our aim was to compare high-resolution MR imaging with digital subtraction angiography for the characterization and diagnosis of various intracranial artery diseases. Thirty-seven patients who had undergone both high-resolution MR imaging and DSA for intracranial artery disease were enrolled in our study (August 2011 to April 2014). The time interval between the high-resolution MR imaging and DSA was within 1 month. The degree of stenosis and the minimal luminal diameter were independently measured by 2 observers in both DSA and high-resolution MR imaging, and the results were compared. Two observers independently diagnosed intracranial artery diseases on DSA and high-resolution MR imaging. The time interval between the diagnoses on DSA and high-resolution MR imaging was 2 weeks. Interobserver diagnostic agreement for each technique and intermodality diagnostic agreement for each observer were acquired. High-resolution MR imaging showed moderate-to-excellent agreement (interclass correlation coefficient = 0.892-0.949; κ = 0.548-0.614) and significant correlations (R = 0.766-892) with DSA on the degree of stenosis and minimal luminal diameter. The interobserver diagnostic agreement was good for DSA (κ = 0.643) and excellent for high-resolution MR imaging (κ = 0.818). The intermodality diagnostic agreement was good (κ = 0.704) for observer 1 and moderate (κ = 0.579) for observer 2, respectively. High-resolution MR imaging may be an imaging method comparable with DSA for the characterization and diagnosis of various intracranial artery diseases. © 2016 by American Journal of Neuroradiology.

Incorporate Imaging Characteristics Into an Arteriovenous Malformation Radiosurgery Plan Evaluation Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Pengpeng; Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY; Wu, Leester

Purpose: To integrate imaging performance characteristics, specifically sensitivity and specificity, of magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) into arteriovenous malformation (AVM) radiosurgery planning and evaluation. Methods and Materials: Images of 10 patients with AVMs located in critical brain areas were analyzed in this retrospective planning study. The image findings were first used to estimate the sensitivity and specificity of MRA and DSA. Instead of accepting the imaging observation as a binary (yes or no) mapping of AVM location, our alternative is to translate the image into an AVM probability distribution map by incorporating imagers' sensitivity and specificity,more » and to use this map as a basis for planning and evaluation. Three sets of radiosurgery plans, targeting the MRA and DSA positive overlap, MRA positive, and DSA positive were optimized for best conformality. The AVM obliteration rate (ORAVM) and brain complication rate served as endpoints for plan comparison. Results: In our 10-patient study, the specificities and sensitivities of MRA and DSA were estimated to be (0.95, 0.74) and (0.71, 0.95), respectively. The positive overlap of MRA and DSA accounted for 67.8% {+-} 4.9% of the estimated true AVM volume. Compared with plans targeting MRA and DSA-positive overlap, plans targeting MRA-positive or DSA-positive improved ORAVM by 4.1% {+-} 1.9% and 15.7% {+-} 8.3%, while also increasing the complication rate by 1.0% {+-} 0.8% and 4.4% {+-} 2.3%, respectively. Conclusions: The impact of imagers' quality should be quantified and incorporated in AVM radiosurgery planning and evaluation to facilitate clinical decision making.« less

Pretransplant soluble CD30 is a better predictor of posttransplant development of donor-specific antibodies and acute vascular rejection than panel reactive antibodies.

PubMed

Vaidya, Smita; Partlow, David; Barnes, Titus; Gugliuzza, Kristine

2006-12-27

This study tests a hypothesis that pretransplant concentration of soluble CD30 (sCD30) is a better predictor of posttransplant development of donor-specific HLA antibodies (DSA) and acute vascular rejection (AVR) than panel reactive HLA antibodies (PRA). Pretransplant sera from 115 patients were evaluated for their PRA and sCD30 concentrations. All patients received calcineurin-inhibitor based immunosuppressive therapy. Objective measurements for rejection were biopsy-proven AVR episodes within first 6 months of the transplant. Posttransplant sera of patients with or without AVR were tested for the presence of DSA. AVR rate was 16% (18/115). Patients positive for PRA and sCD30 tests were at significantly higher risk for AVR compared to those patients negative for both tests (36% versus 5%, p = 0.01). Among negative PRA patients risk for AR was significantly elevated if they were also tested positive for sCD30 concentrations (21% versus 5%, p = 0.04). Of the 18 patients with AVR, 14 were positive for sCD30, and 13 of them (93%) developed DSA posttransplant (p = 0.001) Nineteen patients without AVR were tested for DSA and sCD30 concentrations. Only two of these 19 patients were positive for sCD30 and DSA. AVR was strongly associated with the patients tested positive for both the tests: DSA and sCD30 (p = 0.00007). Furthermore, patients with AVR are more likely to produce DSA than those without AVR (p = 0.02). These data support our hypothesis that patients positive for sCD30 contents are at high risk the development of DSA and AVR posttransplant regardless of their pretransplant PRA.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prinsloo, P. L.; Potgieter, M. S.; Strauss, R. D., E-mail: marius.potgieter@nwu.ac.za

Observations by the Voyager spacecraft in the outer heliosphere presented several challenges for the paradigm of diffusive shock acceleration (DSA) at the solar wind termination shock (TS). In this study, the viability of DSA as a re-acceleration mechanism for galactic electrons is investigated using a comprehensive cosmic-ray modulation model. The results demonstrate that the efficiency of DSA depends strongly on the shape of the electron spectra incident at the TS, which in turn depends on the features of the local interstellar spectrum. Modulation processes such as drifts therefore also influence the re-acceleration process. It is found that re-accelerated electrons makemore » appreciable contributions to intensities in the heliosphere and that increases caused by DSA at the TS are comparable to intensity enhancements observed by Voyager 1 ahead of the TS crossing. The modeling results are interpreted as support for DSA as a re-acceleration mechanism for galactic electrons at the TS.« less

Directed Self-Assembly on Photo-Crosslinked Polystyrene Sub-Layers: Nanopattern Uniformity and Orientation

PubMed Central

Koh, Haeng-Deog; Kim, Mi-Jeong

2016-01-01

A photo-crosslinked polystyrene (PS) thin film is investigated as a potential guiding sub-layer for polystyrene-block-poly (methyl methacrylate) block copolymer (BCP) cylindrical nanopattern formation via topographic directed self-assembly (DSA). When compared to a non-crosslinked PS brush sub-layer, the photo-crosslinked PS sub-layer provided longer correlation lengths of the BCP nanostructure, resulting in a highly uniform DSA nanopattern with a low number of BCP dislocation defects. Depending on the thickness of the sub-layer used, parallel or orthogonal orientations of DSA nanopattern arrays were obtained that covered the entire surface of patterned Si substrates, including both trench and mesa regions. The design of DSA sub-layers and guide patterns, such as hardening the sub-layer by photo-crosslinking, nano-structuring on mesas, the relation between trench/mesa width, and BCP equilibrium period, were explored with a view to developing defect-reduced DSA lithography technology. PMID:28773768

Study of short atmospheric pressure dc glow microdischarge in air

NASA Astrophysics Data System (ADS)

Kudryavtsev, Anatoly; Bogdanov, Eugene; Chirtsov, Alexander; Emelin, Sergey

2011-10-01

The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen and oxygen atoms; ozone molecule; and different nitrogen and oxygen ions with different plasmochemical reactions between them. Simulations predicted the main regions of the dc glow discharges including cathode and anode sheath and plasma of negative glow, Faraday dark space and transition region. Gas heating plays an important role in shaping the discharge profiles. The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen and oxygen atoms; ozone molecule; and different nitrogen and oxygen ions with different plasmochemical reactions between them. Simulations predicted the main regions of the dc glow discharges including cathode and anode sheath and plasma of negative glow, Faraday dark space and transition region. Gas heating plays an important role in shaping the discharge profiles. This work was supported by the FZP and SPbGU

Reaction between Lithium Anode and Polysulfide Ions in a Lithium-Sulfur Battery.

PubMed

Zheng, Dong; Yang, Xiao-Qing; Qu, Deyang

2016-09-08

The reaction between polysulfides and a lithium anode in a Li-S battery was examined using HPLC. The results demonstrated that the polysulfide species with six sulfur atoms or more were reactive with regard to lithium metal. Although the reaction can be greatly inhibited by the addition of LiNO3 in the electrolyte, LiNO3 cannot form a stable protection layer on the Li anode to prevent the reaction during storage. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conductive ceramic composition and method of preparation

DOEpatents

Smith, J.L.; Kucera, E.H.

1991-04-16

A ceramic anode composition is formed of a multivalent metal oxide or oxygenate such as an alkali metal, transition metal oxygenate. The anode is prepared as a non-stoichiometric crystalline structure by reaction and conditioning in a hydrogen gas cover containing minor proportions of carbon dioxide and water vapor. The structure exhibits a single phase and substantially enhanced electrical conductivity over that of the corresponding stoichiometric structure. Unexpectedly, such oxides and oxygenates are found to be stable in the reducing anode fuel gas of a molten carbonate fuel cell. 4 figures.

Micro-sized organometallic compound of ferrocene as high-performance anode material for advanced lithium-ion batteries

NASA Astrophysics Data System (ADS)

Liu, Zhen; Feng, Li; Su, Xiaoru; Qin, Chenyang; Zhao, Kun; Hu, Fang; Zhou, Mingjiong; Xia, Yongyao

2018-01-01

An organometallic compound of ferrocene is first investigated as a promising anode for lithium-ion batteries. The electrochemical properties of ferrocene are conducted by galvanostatic charge and discharge. The ferrocene anode exhibits a high reversible capacity and great cycling stability, as well as superior rate capability. The electrochemical reaction of ferrocene is semi-reversible and some metallic Fe remains in the electrode even after delithiation. The metallic Fe formed in electrode and the stable solid electrolyte interphase should be responsible for its excellent electrochemical performance.

Conductive ceramic composition and method of preparation

DOEpatents

Smith, James L.; Kucera, Eugenia H.

1991-01-01

A ceramic anode composition is formed of a multivalent metal oxide or oxygenate such as an alkali metal, transition metal oxygenate. The anode is prepared as a non-stoichiometric crystalline structure by reaction and conditioning in a hydrogen gas cover containing minor proportions of carbon dioxide and water vapor. The structure exhibits a single phase and substantially enhanced electrical conductivity over that of the corresponding stoichiometric structure. Unexpectedly, such oxides and oxygenates are found to be stable in the reducing anode fuel gas of a molten carbonate fuel cell.

Lithium ion batteries based on nanoporous silicon

DOEpatents

Tolbert, Sarah H.; Nemanick, Eric J.; Kang, Chris Byung-Hwa

2015-09-22

A lithium ion battery that incorporates an anode formed from a Group IV semiconductor material such as porous silicon is disclosed. The battery includes a cathode, and an anode comprising porous silicon. In some embodiments, the anode is present in the form of a nanowire, a film, or a powder, the porous silicon having a pore diameters within the range between 2 nm and 100 nm and an average wall thickness of within the range between 1 nm and 100 nm. The lithium ion battery further includes, in some embodiments, a non-aqueous lithium containing electrolyte. Lithium ion batteries incorporating a porous silicon anode demonstrate have high, stable lithium alloying capacity over many cycles.

Multislice CT Angiography in Renal Artery Stent Evaluation: Prospective Comparison with Intra-Arterial Digital Subtraction Angiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raza, Syed A.; Chughtai, Aamer R.; Wahba, Mona

2004-01-15

Purpose: To assess the role of multislice computed tomography angiography (MCTA) in the evaluation of renal artery stents, using intra-arterial digital subtraction angiography (DSA) as the gold standard. Methods: Twenty consecutive patients (15 men, 5 women) with 23 renal artery stents prospectively underwent both MCTA and DSA. Axial images, multiplanar reconstructions and maximum intensity projection images were used for diagnosis. The MCTA and DSA images were each interpreted without reference to the result of the other investigation. Results:The three cases of restenosis on DSA were detected correctly by MCTA; in 19 cases where MCTA showed a fully patent stent, themore » DSA was also negative. Sensitivity and negative predictive value (NPV) of MCTA were therefore 100%. In four cases, MCTA showed apparently minimal disease which was not shown on DSA. These cases are taken as false positive giving a specificity of 80% and a positive predictive value of 43%. Conclusion: The high sensitivity and NPV suggest MCTA may be useful as a noninvasive screen for renal artery stentrestenosis. MCTA detected mild disease in a few patients which was not confirmed on angiography.« less

High-absorptance high-emittance anodic coating

NASA Technical Reports Server (NTRS)

Le, Huong Giang (Inventor); Chesterfield, John L. (Inventor)

1998-01-01

A colored anodic coating for use on surfaces of substrates, e.g. aluminum substrates in which it is desirable to maintain a high solar absorptance (a) and a high infrared emittance (e), particularly in low earth orbit space environments. This anodic coating is preferably a dark colored coating, and even more preferably a black coating. This coating allows a touch temperature within an acceptable design range to preclude burning of an astronaut in case of contact, but also allows a solar radiation absorption in an amount such that an a/e ratio of unity is achieved. The coating of the invention comprises a first layer in the form of an acid anodized colored anodic layer for achieving a high solar absorptance and a second or high emittance layer in the form of a clear acid anodized layer for achieving a high emittance. The entire coating is quite thin, e.g. 1-2 mils and is quite stable in a hostile space environment of the type encountered in a low earth orbit. The coating is obtained by first creating the high emittance clear anodized coating on the metal surface followed by anodizing using a colored anodizing process.

High-absorptance high-emittance anodic coating

NASA Technical Reports Server (NTRS)

Le, Huong Giang (Inventor); Chesterfield, John L. (Inventor)

1999-01-01

A colored anodic coating for use on surfaces of substrates, e.g. aluminum substrates in which it is desirable to maintain a high solar absorptance (.alpha.) and a high infrared emittance (.epsilon.), particularly in low earth orbit space environments. This anodic coating is preferably a dark colored coating, and even more preferably a black coating. This coating allows a touch temperature within an acceptable design range to preclude burning of an astronaut in case of contact, but also allows a solar radiation absorption in an amount such that an .alpha./.epsilon. ratio of unity is achieved. The coating of the invention comprises a first layer in the form of an acid anodized colored anodic layer for achieving a high solar absorptance and a second or high emittance layer in the form of a clear acid anodized layer for achieving a high emittance. The entire coating is quite thin, e.g. 1-2 mils and is quite stable in a hostile space environment of the type encountered in a low earth orbit. The coating is obtained by first creating the high emittance clear anodized coating on the metal surface followed by anodizing using a colored anodizing process.

Anti-huCD20 Antibody Therapy for Antibody-Mediated Rejection of Renal Allografts in a Mouse Model

PubMed Central

Abe, Toyofumi; Ishii, Daisuke; Gorbacheva, Victoria; Kohei, Naoki; Tsuda, Hidetoshi; Tanaka, Toshiaki; Dvorina, Nina; Nonomura, Norio; Takahara, Shiro; Valujskikh, Anna; Baldwin, William M.; Fairchild, Robert L.

2016-01-01

We have reported that B6.CCR5−/− mice reject renal allografts with high serum donor-specific antibody (DSA) titers and marked C4d deposition in grafts, features consistent with AMR. B6.huCD20/CCR5−/− mice, where human CD20 expression is restricted to B cells, rejected A/J renal allografts by day 26 post-transplant with DSA first detected in serum on day 5 post-transplant and increased thereafter. Recipient treatment with anti-huCD20 mAb prior to the transplant and weekly up to 7 weeks post-transplant promoted long-term allograft survival (> 100 days) with low DSA titers. To investigate the effect of B cell depletion at the time serum DSA was first detected, recipients were treated with anti-huCD20 mAb on days 5, 8 and 12 post-transplant. This regimen significantly reduced DSA titers and graft inflammation on day 15 post-transplant and prolonged allograft survival > 60 days. However, DSA returned to the titers observed in control treated recipients by day 30 post-transplant and histological analyses on day 60 post-transplant indicated severe interstitial fibrosis. These results indicate that anti-huCD20 mAb had the greatest effect as a prophylactic treatment and that the distinct kinetics of DSA responses accounts for acute renal allograft failure versus the development of fibrosis. PMID:25731734

The Presence of Pretransplant HLA Antibodies Does Not Impact the Development of Chronic Lung Allograft Dysfunction or CLAD-Related Death.

PubMed

Zazueta, Oscar E; Preston, Sara E; Moniodis, Anna; Fried, Sabrina; Kim, Miae; Townsend, Keri; Wood, Isabelle; Boukedes, Steve; Guleria, Indira; Camp, Phillip; El-Chemaly, Souheil; Rosas, Ivan O; Chandraker, Anil; Milford, Edgar; Goldberg, Hilary J

2017-09-01

Development of donor-specific antibodies (DSA) after lung transplantation is associated with antibody mediated rejection, acute cellular rejection, and bronchiolitis obliterans syndrome; however, the significance of circulating antibodies before transplant remains unclear. We performed a retrospective cohort study including recipients of primary lung transplants between 2008 and 2012. We assessed the impact of circulating HLA and noncytotoxic DSA detected before transplant on development of Chronic Lung Allograft Dysfunction (CLAD) or CLAD-related death. 30% of subjects had circulating class I antibodies alone, 4% Class II, and 14.4% class I and class II at mean fluorescent intensity greater than 1000. Nine percent of the subjects had DSA class I, 9% class II, and 2.4% both DSA classes 1 and 2. Neither the presence of circulating antibodies (adjusted hazard ratio, 0.87; 95% confidence interval, 0.50-1.54) nor the presence of DSA (adjusted hazard ratio, 1.56; 95% confidence interval, 0.77-3.18) before transplant at mean fluorescent intensity greater than 1000 was associated with the development of CLAD or CLAD-related death. Although in previous studies we have shown an increased incidence of antibody-mediated rejection in patients with pretransplant DSA, neither the presence of HLA antibodies nor DSA translated to an increased risk of allograft dysfunction or death if prospective crossmatch testing was negative. Prospective studies are needed to define the impact of pretransplant sensitization on lung transplant recipients.

Uniform Incorporation of Flocculent Molybdenum Disulfide Nanostructure into Three-Dimensional Porous Graphene as an Anode for High-Performance Lithium Ion Batteries and Hybrid Supercapacitors.

PubMed

Zhang, Fan; Tang, Yongbing; Liu, Hui; Ji, Hongyi; Jiang, Chunlei; Zhang, Jing; Zhang, Xiaolong; Lee, Chun-Sing

2016-02-01

Hybrid supercapacitors (HSCs) with lithium-ion battery-type anodes and electric double layer capacitor-type cathodes are attracting extensive attention and under wide investigation because of their combined merits of both high power and energy density. However, the performance of most HSCs is limited by low kinetics of the battery-type anode which cannot match the fast kinetics of the capacitor-type cathode. In this study, we have synthesized a three-dimensional (3D) porous composite with uniformly incorporated MoS2 flocculent nanostructure onto 3D graphene via a facile solution-processed method as an anode for high-performance HSCs. This composite shows significantly enhanced electrochemical performance due to the synergistic effects of the conductive graphene sheets and the interconnected porous structure, which exhibits a high rate capability of 688 mAh/g even at a high current density of 8 A/g and a stable cycling performance (997 mAh/g after 700 cycles at 2 A/g). Furthermore, by using this composite as the anode for HSCs, the HSC shows a high energy density of 156 Wh/kg at 197 W/kg, which also remains at 97 Wh/kg even at a high power density of 8314 W/kg with a stable cycling life, among the best results of the reported HSCs thus far.

In Situ Activation of 3D Porous Bi/Carbon Architectures: Toward High-Energy and Stable Nickel-Bismuth Batteries.

PubMed

Zeng, Yinxiang; Lin, Ziqi; Wang, Zifan; Wu, Mingmei; Tong, Yexiang; Lu, Xihong

2018-05-01

To achieve high-energy and stable aqueous rechargeable batteries, state-of-the art of anode materials are needed. Bismuth (Bi) has recently emerged as an attractive anode material due to its highly reversible redox reaction and suitable negative operating working window. However, the capacity and durability of currently reported Bi anodes are still far from satisfactory. Here, an in situ activation strategy is reported to prepare a 3D porous high-density Bi nanoparticles/carbon architecture (P-Bi-C) as an efficient anode for nickel-bismuth batteries. Taking advantages of the fast channels for charge transfer and ion diffusion, enhanced wettability, and accessible surface area, the highly loaded P-Bi-C electrode delivers a remarkable capacity of 2.11 mA h cm -2 as well as high rate capability (1.19 mA h cm -2 at 120 mA cm -2 ). To highlight, a robust aqueous rechargeable Ni//Bi battery based on the P-Bi-C anode is first constructed, achieving decent capacity (141 mA h g -1 ), impressive durability (94% capacity retention after 5000 cycles), and admirable energy density (16.9 mW h cm -3 ). This work paves the way for designing superfast nickel-bismuth batteries with high energy and long-life and may inspire new development for aqueous rechargeable batteries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monovalent manganese based anodes and co-solvent electrolyte for stable low-cost high-rate sodium-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Firouzi, Ali; Qiao, Ruimin; Motallebi, Shahrokh

The demand of sustainable power supply requires high-performance cost-effective energy storage technologies. Here in this paperwe report a high-rate long-life low-cost sodium-ion battery full-cell system by innovating both the anode and the electrolyte. The redox couple of manganese(I/II) in Prussian blue analogs enables a high-rate and stable anode. Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering provide direct evidence suggesting the existence of monovalent manganese in the charged anode. There is a strong hybridization between cyano ligands and manganese-3d states, which benefits the electronic property for improving rate performance. Additionally, we employ an organic-aqueous cosolvent electrolyte to solve themore » long-standing solubility issue of Prussian blue analogs. A full-cell sodium-ion battery with low-cost Prussian blue analogs in both electrodes and co-solvent electrolyte retains 95% of its initial discharge capacity after 1000 cycles at 1C and 9 5% depth of discharge. The revealed manganese(I/II) redox couple inspires conceptual innovations of batteries based on atypical oxidation states.« less

Si-FeSi2/C nanocomposite anode materials produced by two-stage high-energy mechanical milling

NASA Astrophysics Data System (ADS)

Yang, Yun Mo; Loka, Chadrasekhar; Kim, Dong Phil; Joo, Sin Yong; Moon, Sung Whan; Choi, Yi Sik; Park, Jung Han; Lee, Kee-Sun

2017-05-01

High capacity retention Silicon-based nanocomposite anode materials have been extensively explored for use in lithium-ion rechargeable batteries. Here we report the preparation of Si-FeSi2/C nanocomposite through scalable a two-stage high-energy mechanical milling process, in which nano-scale Si-FeSi2 powders are besieged by the carbon (graphite/amorphous phase) layer; and investigation of their structure, morphology and electrochemical performance. Raman analysis revealed that the carbon layer structure comprised of graphitic and amorphous phase rather than a single amorphous phase. Anodes fabricated with the Si-FeSi2/C showed excellent electrochemical behavior such as a first discharge capacity of 1082 mAh g-1 and a high capacity retention until the 30th cycle. A remarkable coulombic efficiency of 99.5% was achieved within a few cycles. Differential capacity plots of the Si-FeSi2/C anodes revealed a stable lithium reaction with Si for lithiation/delithiation. The enhanced electrochemical properties of the Si-FeSi2/C nanocomposite are mainly attributed to the nano-size Si and stable solid electrolyte interface formation and highly conductive path driven by the carbon layer.

Monovalent manganese based anodes and co-solvent electrolyte for stable low-cost high-rate sodium-ion batteries

DOE PAGES

Firouzi, Ali; Qiao, Ruimin; Motallebi, Shahrokh; ...

2018-02-28

The demand of sustainable power supply requires high-performance cost-effective energy storage technologies. Here in this paperwe report a high-rate long-life low-cost sodium-ion battery full-cell system by innovating both the anode and the electrolyte. The redox couple of manganese(I/II) in Prussian blue analogs enables a high-rate and stable anode. Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering provide direct evidence suggesting the existence of monovalent manganese in the charged anode. There is a strong hybridization between cyano ligands and manganese-3d states, which benefits the electronic property for improving rate performance. Additionally, we employ an organic-aqueous cosolvent electrolyte to solve themore » long-standing solubility issue of Prussian blue analogs. A full-cell sodium-ion battery with low-cost Prussian blue analogs in both electrodes and co-solvent electrolyte retains 95% of its initial discharge capacity after 1000 cycles at 1C and 9 5% depth of discharge. The revealed manganese(I/II) redox couple inspires conceptual innovations of batteries based on atypical oxidation states.« less

Core-Shell Coating Silicon Anode Interfaces with Coordination Complex for Stable Lithium-Ion Batteries.

PubMed

Zhou, Jinqiu; Qian, Tao; Wang, Mengfan; Xu, Na; Zhang, Qi; Li, Qun; Yan, Chenglin

2016-03-02

In situ core-shell coating was used to improve the electrochemical performance of Si-based anodes with polypyrrole-Fe coordination complex. The vast functional groups in the organometallic coordination complex easily formed hydrogen bonds when in situ modifying commercial Si nanoparticles. The incorporation of polypyrrole-Fe resulted in the conformal conductive coating surrounding each Si nanoparticle, not only providing good electrical connection to the particles but also promoting the formation of a stable solid-electrolyte-interface layer on the Si electrode surface, enhancing the cycling properties. As an anode material for Li-ion batteries, modified silicon powders exhibited high reversible capacity (3567 mAh/g at 0.3 A/g), good rate property (549.12 mAh/g at 12 A/g), and excellent cycling performance (reversible capacity of 1500 mAh/g after 800 cycles at 1.2 A/g). The constructed novel concept of core-shell coating Si particles presented a promising route for facile and large-scale production of Si-based anodes for extremely durable Li-ion batteries, which provided a wide range of applications in the field of energy storage of the renewable energy derived from the solar energy, hydropower, tidal energy, and geothermal heat.

Self-ordered, controlled structure nanoporous membranes using constant current anodization.

PubMed

Lee, Kwan; Tang, Yun; Ouyang, Min

2008-12-01

We report a constant current (CC) based anodization technique to fabricate and control structure of mechanically stable anodic aluminum oxide (AAO) membranes with a long-range ordered hexagonal nanopore pattern. For the first time we show that interpore distance (Dint) of a self-ordered nanopore feature can be continuously tuned over a broad range with CC anodization and is uniquely defined by the conductivity of sulfuric acid as electrolyte. We further demonstrate that this technique can offer new degrees of freedom for engineering planar nanopore structures by fine tailoring the CC based anodization process. Our results not only facilitate further understanding of self-ordering mechanism of alumina membranes but also provide a fast, simple (without requirement of prepatterning or preoxide layer), and flexible methodology for controlling complex nanoporous structures, thus offering promising practical applications in nanotechnology.

SU-E-I-26: Estimation of Micro-Angiographic Fluoroscope (MAF) Gain Settings for Digital Subtraction Angiography (DSA) Based on the Fluoroscopic Exposure.

PubMed

Ionita, C; Loughran, B; Nagesh, S Setlur; Jain, A; Bednarek, D; Rudin, S

2012-06-01

The MAF is a new high-resolution detector which is being clinically evaluated in neuro-vascular procedures. The detector contains a large-dynamic-range, high-sensitivity light image intensifier with variable gain. Since the MAF is a research prototype only partially integrated with the clinical system, x-ray technique parameters must be set manually. To improve workflow we developed an automatic method to estimate and set the proper LII voltage (MAF gain) for DSA acquisition based on the fluoroscopic parameters. The detector entrance exposure (XD) can be written as the x-ray tube output exposure (Xo) times an object attenuation factor and an inverse-square correction. If the object attenuation, scatter and distances are unchanged and the effect of x-ray kVp changes are neglected, then the DSA XD can be expressed as the ratio of Xo(DSA)/Xo(Fluoroscopy) multiplied with XD(fluoroscopy). We measured Xo for fluoroscopy and DSA for mAs and kVp ranges appropriate to neuro- vascular interventions and fit the data with a 2D function. To estimate the XD(Fluoroscopy) we derived a curve of XD versus LII-voltage for a mid- dynamic-range average pixel gray-level. Since the MAF system during clinical fluoroscopy automatically adjusts the LII voltage until the desired gray-level value is achieved, by reading that voltage we can estimate the XD(Fluoroscopy). Using the 2D-fit function, Xo(DSA) is automatically calculated for the kVp and mA values set and XD(DSA) can be estimated using the relation above. Using the inverse LII calibration curve, the proper LII-voltage can be determined for the desired average gray-level. The algorithm was implemented and evaluated in thirty-two in-vivo DSA runs on rabbits. The proper LII voltage was selected in all cases with no failures. Using the fluoroscopic LII gain setting to determine the appropriate DSA setting can greatly improve the workflow in clinical evaluations of the MAF. NIH Grants R01-EB008425, R01-EB002873 and an equipment grant from Toshiba Medical Systems Corp. © 2012 American Association of Physicists in Medicine.

Benign Prostatic Hyperplasia: Cone-Beam CT in Conjunction with DSA for Identifying Prostatic Arterial Anatomy.

PubMed

Wang, Mao Qiang; Duan, Feng; Yuan, Kai; Zhang, Guo Dong; Yan, Jieyu; Wang, Yan

2017-01-01

Purpose To describe findings in prostatic arteries (PAs) at digital subtraction angiography (DSA) and cone-beam computed tomography (CT) that allow identification of benign prostatic hyperplasia and to determine the value added with the use of cone-beam CT. Materials and Methods This retrospective single-institution study was approved by the institutional review board, and the requirement for written informed consent was waived. From February 2009 to December 2014, a total of 148 patients (mean age ± standard deviation, 70.5 years ± 14.5) underwent DSA of the internal iliac arteries and cone-beam CT with a flat-detector angiographic system before they underwent prostate artery embolization. Both the DSA and cone-beam CT images were evaluated by two interventional radiologists to determine the number of independent PAs and their origins and anastomoses with adjacent arteries. The exact McNemar test was used to compare the detection rate of the PAs and the anastomoses with DSA and with cone-beam CT. Results The PA anatomy was evaluated successfully by means of cone-beam CT in conjunction with DSA in all patients. Of the 296 pelvic sides, 274 (92.6%) had only one PA. The most frequent PA origin was the common gluteal-pudendal trunk with the superior vesicular artery in 118 (37.1%), followed by the anterior division of the internal iliac artery in 99 (31.1%), and the internal pudendal artery in 77 (24.2%) pelvic sides. In 67 (22.6%) pelvic sides, anastomoses to adjacent arteries were documented. The numbers of PA origins and anastomoses, respectively, that could be identified were significantly higher with cone-beam CT (301 of 318 [94.7%] and 65 of 67 [97.0%]) than with DSA (237 [74.5%] and 39 [58.2%], P < .05). Cone-beam CT provided essential information that was not available with DSA in 90 of 148 (60.8%) patients. Conclusion Cone-beam CT is a useful adjunctive technique to DSA for identification of the PA anatomy and provides information to help treatment planning during prostatic arterial embolization. © RSNA, 2016.

A dynamic inert metal anode.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hryn, J. N.

1998-11-09

A new concept for a stable anode for aluminum electrowinning is described. The anode consists of a cup-shaped metal alloy container filled with a molten salt that contains dissolved aluminum. The metal alloy can be any of a number of alloys, but it must contain aluminum as a secondary alloying metal. A possible alloy composition is copper with 5 to 15 weight percent aluminum. In the presence of oxygen, aluminum on the metal anode's exterior surface forms a continuous alumina film that is thick enough to protect the anode from chemical attack by cryolite during electrolysis and thin enough tomore » maintain electrical conductivity. However, the alumina film is soluble in cryolite, so it must be regenerated in situ. Film regeneration is achieved by the transport of aluminum metal from the anode's molten salt interior through the metal wall to the anode's exterior surface, where the transported aluminum oxidizes to alumina in the presence of evolving oxygen to maintain the protective alumina film. Periodic addition of aluminum metal to the anode's interior keeps the aluminum activity in the molten salt at the desired level. This concept for an inert anode is viable as long as the amount of aluminum produced at the cathode greatly exceeds the amount of aluminum required to maintain the anode's protective film.« less

A pomegranate-inspired nanoscale design for large-volume-change lithium battery anodes

NASA Astrophysics Data System (ADS)

Liu, Nian; Lu, Zhenda; Zhao, Jie; McDowell, Matthew T.; Lee, Hyun-Wook; Zhao, Wenting; Cui, Yi

2014-03-01

Silicon is an attractive material for anodes in energy storage devices, because it has ten times the theoretical capacity of its state-of-the-art carbonaceous counterpart. Silicon anodes can be used both in traditional lithium-ion batteries and in more recent Li-O2 and Li-S batteries as a replacement for the dendrite-forming lithium metal anodes. The main challenges associated with silicon anodes are structural degradation and instability of the solid-electrolyte interphase caused by the large volume change (~300%) during cycling, the occurrence of side reactions with the electrolyte, and the low volumetric capacity when the material size is reduced to a nanometre scale. Here, we propose a hierarchical structured silicon anode that tackles all three of these problems. Our design is inspired by the structure of a pomegranate, where single silicon nanoparticles are encapsulated by a conductive carbon layer that leaves enough room for expansion and contraction following lithiation and delithiation. An ensemble of these hybrid nanoparticles is then encapsulated by a thicker carbon layer in micrometre-size pouches to act as an electrolyte barrier. As a result of this hierarchical arrangement, the solid-electrolyte interphase remains stable and spatially confined, resulting in superior cyclability (97% capacity retention after 1,000 cycles). In addition, the microstructures lower the electrode-electrolyte contact area, resulting in high Coulombic efficiency (99.87%) and volumetric capacity (1,270 mAh cm-3), and the cycling remains stable even when the areal capacity is increased to the level of commercial lithium-ion batteries (3.7 mAh cm-2).

On the way to total integration of prosthetic pylon with residuum

PubMed Central

Pitkin, Mark

2010-01-01

Two decades after introducing threaded titanium dental implants, Dr. Per-Ingvar Brånemark used a similar technique in the 1980s to pioneer the direct skeletal attachment (DSA) of limb prostheses. He and his colleagues used convincing clinical experience to overcome the skepticism of their peers, affording a new dimension of prosthetic rehabilitation to almost 100 individuals with amputation. As a result, more research has been initiated worldwide to move DSA to a level of greater safety, longevity, and reliability. This review highlights the trends and milestones in current DSA development. It also identifies ideas from previous studies in various fields that may be useful in future DSA development. PMID:19675987

Addition of acetate improves stability of power generation using microbial fuel cells treating domestic wastewater.

PubMed

Stager, Jennifer L; Zhang, Xiaoyuan; Logan, Bruce E

2017-12-01

Power generation using microbial fuel cells (MFCs) must provide stable, continuous conversion of organic matter in wastewaters into electricity. However, when relatively small diameter (0.8cm) graphite fiber brush anodes were placed close to the cathodes in MFCs, power generation was unstable during treatment of low strength domestic wastewater. One reactor produced 149mW/m 2 before power generation failed, while the other reactor produced 257mW/m 2 , with both reactors exhibiting severe power overshoot in polarization tests. Using separators or activated carbon cathodes did not result in stable operation as the reactors continued to exhibit power overshoot based on polarization tests. However, adding acetate (1g/L) to the wastewater produced stable performance during fed batch and continuous flow operation, and there was no power overshoot in polarization tests. These results highlight the importance of wastewater strength and brush anode size for producing stable and continuous power in compact MFCs. Copyright © 2017 Elsevier B.V. All rights reserved.

Arterial Blood Flow Measurement Using Digital Subtraction Angiography (DSA)

NASA Astrophysics Data System (ADS)

Swanson, David K.; Myerowitz, P. David; Van Lysel, Michael S.; Peppler, Walter W.; Fields, Barry L.; Watson, Kim M.; O'Connor, Julia

1984-08-01

Standard angiography demonstrates the anatomy of arterial occlusive disease but not its physiological signficance. Using intravenous digital subtraction angiography (DSA), we investigated transit-time videodensitometric techniques in measuring femoral arterial flows in dogs. These methods have been successfully applied to intraarterial DSA but not to intravenous DSA. Eight 20 kg dogs were instrumented with an electromagnetic flow probe and a balloon occluder above an imaged segment of femoral artery. 20 cc of Renografin 76 was power injected at 15 cc/sec into the right atrium. Flow in the femoral artery was varied by partial balloon occlusion or peripheral dilatation following induced ischemia resulting in 51 flow measurements varying from 15 to 270 cc/min. Three different transit-time techniques were studied: crosscorrelation, mean square error, and two leading edge methods. Correlation between videodensitometry and flowmeter measurements using these different techniques ranged from 0.78 to 0.88 with a mean square error of 29 to 37 cc/min. Blood flow information using several different transit-time techniques can be obtained with intravenous DSA.

Stabilizing the baseline current of a microbial fuel cell-based biosensor through overpotential control under non-toxic conditions.

PubMed

Stein, Nienke E; Hamelers, Hubertus V M; Buisman, Cees N J

2010-04-01

A MFC-based biosensor can act as online toxicity sensor. Electrical current is a direct linear measure for metabolic activity of electrochemically active microorganisms. Microorganisms gain energy from anodic overpotential and current strongly depends on anodic overpotential. Therefore control of anodic overpotential is necessary to detect toxic events and prevent false positive alarms. Anodic overpotential and thus current is influenced by anode potential, pH, substrate and bicarbonate concentrations. In terms of overpotential all factor showed a comparable effect, anode potential 1.2% change in current density per mV, pH 0.43%/mV, bicarbonate 0.75%/mV and acetate 0.8%/mV. At acetate saturation the maximum acetate conversion rate is reached and with that a constant bicarbonate concentration. Control of acetate and bicarbonate concentration can be less strict than control of anode potential and pH. Current density changes due to changing anode potential and pH are in the same order of magnitude as changes due to toxicity. Strict control of pH and anode potential in a small range is required. The importance of anodic overpotential control for detection of toxic compounds is shown. To reach a stable baseline current under nontoxic conditions a MFC-based biosensor should be operated at controlled anode potential, controlled pH and saturated substrate concentrations. 2009 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Segal-Peretz, Tamar; Zhou, Chun; Ren, Jiaxing

The three-dimensional assembly of poly (styrene-b-methyl methacrylate) (PS-b-PMMA) in chemoepitaxy and graphoepitaxy directed self-assembly (DSA) was investigated using scanning transmission electron microscopy (STEM) tomography. The tomographic characterization revealed hidden morphologies and defects at the BCP- chemical pattern interface in lamellar DSA, and probed the formation of cylinders at the bottom of cylindrical DSA for contact hole shrink. Lastly, future work will include control over 3D assembly in sub-10 nm processes.

A LabVIEW Platform for Preclinical Imaging Using Digital Subtraction Angiography and Micro-CT.

PubMed

Badea, Cristian T; Hedlund, Laurence W; Johnson, G Allan

2013-01-01

CT and digital subtraction angiography (DSA) are ubiquitous in the clinic. Their preclinical equivalents are valuable imaging methods for studying disease models and treatment. We have developed a dual source/detector X-ray imaging system that we have used for both micro-CT and DSA studies in rodents. The control of such a complex imaging system requires substantial software development for which we use the graphical language LabVIEW (National Instruments, Austin, TX, USA). This paper focuses on a LabVIEW platform that we have developed to enable anatomical and functional imaging with micro-CT and DSA. Our LabVIEW applications integrate and control all the elements of our system including a dual source/detector X-ray system, a mechanical ventilator, a physiological monitor, and a power microinjector for the vascular delivery of X-ray contrast agents. Various applications allow cardiac- and respiratory-gated acquisitions for both DSA and micro-CT studies. Our results illustrate the application of DSA for cardiopulmonary studies and vascular imaging of the liver and coronary arteries. We also show how DSA can be used for functional imaging of the kidney. Finally, the power of 4D micro-CT imaging using both prospective and retrospective gating is shown for cardiac imaging.

A LabVIEW Platform for Preclinical Imaging Using Digital Subtraction Angiography and Micro-CT

PubMed Central

Badea, Cristian T.; Hedlund, Laurence W.; Johnson, G. Allan

2013-01-01

CT and digital subtraction angiography (DSA) are ubiquitous in the clinic. Their preclinical equivalents are valuable imaging methods for studying disease models and treatment. We have developed a dual source/detector X-ray imaging system that we have used for both micro-CT and DSA studies in rodents. The control of such a complex imaging system requires substantial software development for which we use the graphical language LabVIEW (National Instruments, Austin, TX, USA). This paper focuses on a LabVIEW platform that we have developed to enable anatomical and functional imaging with micro-CT and DSA. Our LabVIEW applications integrate and control all the elements of our system including a dual source/detector X-ray system, a mechanical ventilator, a physiological monitor, and a power microinjector for the vascular delivery of X-ray contrast agents. Various applications allow cardiac- and respiratory-gated acquisitions for both DSA and micro-CT studies. Our results illustrate the application of DSA for cardiopulmonary studies and vascular imaging of the liver and coronary arteries. We also show how DSA can be used for functional imaging of the kidney. Finally, the power of 4D micro-CT imaging using both prospective and retrospective gating is shown for cardiac imaging. PMID:27006920

Assessment of blood supply to intracranial pathologies in children using MR digital subtraction angiography.

PubMed

Chooi, Weng Kong; Connolly, Dan J A; Coley, Stuart C; Griffiths, Paul D

2006-10-01

MR digital subtraction angiography (MR-DSA) is a contrast-enhanced MR angiographic sequence that enables time-resolved evaluation of the cerebral circulation. We describe the feasibility and technical success of our attempts at MR-DSA for the assessment of intracranial pathology in children. We performed MR-DSA in 15 children (age range 5 days to 16 years) referred for MR imaging because of known or suspected intracranial pathology that required a dynamic assessment of the cerebral vasculature. MR-DSA consisted of a thick (6-10 mm) slice-selective RF-spoiled fast gradient-echo sequence (RF-FAST) acquired before and during passage of an intravenously administered bolus of Gd-DTPA. The images were subtracted and viewed as a cine loop. MR-DSA was performed successfully in all patients. High-flow lesions were shown in four patients; these included vein of Galen aneurysmal malformation, dural fistula, and two partially treated arteriovenous malformations (AVMs). Low-flow lesions were seen in three patients, all of which were tumours. Normal flow was confirmed in eight patients including two with successfully treated AVMs, and in three patients with cavernomas. Our early experience suggests that MR-DSA is a realistic, non-invasive alternative to catheter angiography in certain clinical settings.

Study on Dynamic Strain Aging and Low-Cycle Fatigue of Stainless Steel in Ultra-Supercritical Unit

NASA Astrophysics Data System (ADS)

Hongwei, Zhou; Yizhu, He; Jizu, Lv; Sixian, Rao

Dynamic strain aging (DSA) and low-cycle fatigue (LCF) behavior of TP347H stainless steel in ultra-supercritical unit were investigated at 550-650 °C. All the LCF tests were carried out under a fully-reversed, total axial strain control mode at the total strain amplitude from ±0.2% to ±1.0%. The effects of DSA in cyclic stress response, microstructure evolution and fatigue fracture surfaces and fatigue life were investigated in detail. The results show that DSA occurs during tensile, which is manifested as serrated flow in tensile stress-strain curves. The apparent activation energy for appearing of serrations in tensile stress-strain curves was 270 kJ/mol. Pipe diffusion of substitutional solutes such as Cr and Nb along the dislocation core, and strong interactions between segregated solutes and dislocations are considered as the mechanism of DSA. DSA partly restricts dislocation cross-slip, and dislocation cross-slip and planar-slip happen simultaneously during LCF. A lot of planar structures form, which is due to dislocation gliding on the special plane. This localized deformation structures result in many crack initiation sites. Meanwhile, DSA hardening increases cyclic stress response, accelerating crack propagation, which reduces high temperature strain fatigue life of steel.

Comparison of Intraoperative Indocyanine Green Angiography and Digital Subtraction Angiography for Clipping of Intracranial Aneurysms

PubMed Central

Doss, Vinodh T.; Goyal, Nitin; Humphries, William; Hoit, Dan; Arthur, Adam; Elijovich, Lucas

2015-01-01

Background Residual aneurysm after microsurgical clipping carries a risk of aneurysm growth and rupture. Digital subtraction angiography (DSA) remains the standard to determine the adequacy of clipping. Intraoperative indocyanine green (ICG) angiography is increasingly utilized to confirm optimal clip positioning across the neck and to evaluate the adjacent vasculature. Objective We evaluated the correlation between ICG and DSA in clipped intracranial aneurysms. Methods A retrospective study of patients who underwent craniotomy and microsurgical clipping of intracranial aneurysms with ICG for 2 years. Patient characteristics, presentation details, operative reports, and pre- and postclipping angiographic images were reviewed to determine the adequacy of the clipping. Results Forty-seven patients underwent clipping with ICG and postoperative DSA: 57 aneurysms were clipped; 23 patients (48.9%) presented with subarachnoid hemorrhage. Nine aneurysms demonstrated a residual on DSA not identified on ICG (residual sizes ranged from 0.5 to 4.3 mm; average size: 1.8 mm). Postoperative DSA demonstrated no branch occlusions. Conclusion Intraoperative ICG is useful in the clipping of intracranial aneurysms to ensure a gross patency of branch vessels; however, the presence of residual aneurysms and subtle changes in flow in branch vessels is best seen by DSA. This has important clinical implications with regard to follow-up imaging and surgical/endovascular management. PMID:26279659

Phosphorus-doped silicon nanorod anodes for high power lithium-ion batteries.

PubMed

Yan, Chao; Liu, Qianru; Gao, Jianzhi; Yang, Zhibo; He, Deyan

2017-01-01

Heavy-phosphorus-doped silicon anodes were fabricated on CuO nanorods for application in high power lithium-ion batteries. Since the conductivity of lithiated CuO is significantly better than that of CuO, after the first discharge, the voltage cut-off window was then set to the range covering only the discharge-charge range of Si. Thus, the CuO core was in situ lithiated and acts merely as the electronic conductor in the following cycles. The Si anode presented herein exhibited a capacity of 990 mAh/g at the rate of 9 A/g after 100 cycles. The anode also presented a stable rate performance even at a current density as high as 20 A/g.

Composite Li metal anode with vertical graphene host for high performance Li-S batteries

NASA Astrophysics Data System (ADS)

Zhang, Y. J.; Liu, S. F.; Wang, X. L.; Zhong, Y.; Xia, X. H.; Wu, J. B.; Tu, J. P.

2018-01-01

Efficient and stable operation of a lithium metal anode has become the enabling factor for next-generation high energy density storage system. Here, vertical graphene (VG) arrays are used as the scaffold structure for high performance Li metal batteries. The melt infusion method is employed to encapsulate Li inside the VG scaffold structure, and the lithiophilic Si layer is coated onto the array surface by magnetron sputtering to assist this melt-infusion process. The porous scaffold structure can control the volume expansion and inhibit the formation of dendritic lithium significantly, leading to the excellent electrochemical performance of the Li composite anode. In addition, the Li-S full batteries with the composite anode display enhanced cycling reversibility.

Self-Organized Formation of Short TiO2 Nanotube Arrays By Complete Anodization of Ti Thin Films

NASA Astrophysics Data System (ADS)

Okada, Masahisa; Tajima, Kazuki; Yamada, Yasusei; Yoshimura, Kazuki

We investigate the self-organized growth of short TiO2 nanotubes by complete anodization of Ti thin films deposited on Si substrates in ethylene glycol electrolytes with small addition of NH4F. During the anodization process, real-time inspection of the current transient is performed to anodize the Ti films completely. X-ray photoelectron spectroscopy and scanning electron microscopy are employed to characterize the resulting samples. We find that the length of the formed TiO2 nanotubes is governed by the thickness of Ti thin films independently of the tube diameter. Short TiO2 nanotubes are also found to be stable up to 550 °C in air atmosphere even after crystallization to rutile.

Standardized volume rendering for magnetic resonance angiography measurements in the abdominal aorta.

PubMed

Persson, A; Brismar, T B; Lundström, C; Dahlström, N; Othberg, F; Smedby, O

2006-03-01

To compare three methods for standardizing volume rendering technique (VRT) protocols by studying aortic diameter measurements in magnetic resonance angiography (MRA) datasets. Datasets from 20 patients previously examined with gadolinium-enhanced MRA and with digital subtraction angiography (DSA) for abdominal aortic aneurysm were retrospectively evaluated by three independent readers. The MRA datasets were viewed using VRT with three different standardized transfer functions: the percentile method (Pc-VRT), the maximum-likelihood method (ML-VRT), and the partial range histogram method (PRH-VRT). The aortic diameters obtained with these three methods were compared with freely chosen VRT parameters (F-VRT) and with maximum intensity projection (MIP) concerning inter-reader variability and agreement with the reference method DSA. F-VRT parameters and PRH-VRT gave significantly higher diameter values than DSA, whereas Pc-VRT gave significantly lower values than DSA. The highest interobserver variability was found for F-VRT parameters and MIP, and the lowest for Pc-VRT and PRH-VRT. All standardized VRT methods were significantly superior to both MIP and F-VRT in this respect. The agreement with DSA was best for PRH-VRT, which was the only method with a mean error below 1 mm and which also had the narrowest limits of agreement (95% of cases between 2.1 mm below and 3.1 mm above DSA). All the standardized VRT methods compare favorably with MIP and VRT with freely selected parameters as regards interobserver variability. The partial range histogram method, although systematically overestimating vessel diameters, gives results closest to those of DSA.

Development and Testing of High Surface Area Iridium Anodes for Molten Oxide Electrolysis

NASA Technical Reports Server (NTRS)

Shchetkovskiy, Anatoliy; McKechnie, Timothy; Sadoway, Donald R.; Paramore, James; Melendez, Orlando; Curreri, Peter A.

2010-01-01

Processing of lunar regolith into oxygen for habitat and propulsion is needed to support future space missions. Direct electrochemical reduction of molten regolith is an attractive method of processing, because no additional chemical reagents are needed. The electrochemical processing of molten oxides requires high surface area, inert anodes. Such electrodes need to be structurally robust at elevated temperatures (1400-1600?C), be resistant to thermal shock, have good electrical conductivity, be resistant to attack by molten oxide (silicate), be electrochemically stable and support high current density. Iridium with its high melting point, good oxidation resistance, superior high temperature strength and ductility is the most promising candidate for anodes in high temperature electrochemical processes. Several innovative concepts for manufacturing such anodes by electrodeposition of iridium from molten salt electrolyte (EL-Form? process) were evaluated. Iridium electrodeposition to form of complex shape components and coating was investigated. Iridium coated graphite, porous iridium structure and solid iridium anodes were fabricated. Testing of electroformed iridium anodes shows no visible degradation. The result of development, manufacturing and testing of high surface, inert iridium anodes will be presented.

Development and Testing of High Surface Area Iridium Anodes for Molten Oxide Electrolysis

NASA Technical Reports Server (NTRS)

Shchetkovskiy, Anatoliy; McKechnie, Timothy; Sadoway, Donald R.; Paramore, James; Melendez, Orlando; Curreri, Peter A.

2010-01-01

Processing of lunar regolith into oxygen for habitat and propulsion is needed to support future space missions. Direct electrochemical reduction of molten regolith is an attractive method of processing, because no additional chemical reagents are needed. The electrochemical processing of molten oxides requires high surface area, inert anodes. Such electrodes need to be structurally robust at elevated temperatures (1400-1600 C), be resistant to thermal shock, have good electrical conductivity, be resistant to attack by molten oxide (silicate), be electrochemically stable and support high current density. Iridium with its high melting point, good oxidation resistance, superior high temperature strength and ductility is the most promising candidate for anodes in high temperature electrochemical processes. Several innovative concepts for manufacturing such anodes by electrodeposition of iridium from molten salt electrolyte (EL-Form process) were evaluated. Iridium electrodeposition to form of complex shape components and coating was investigated. Iridium coated graphite, porous iridium structure and solid iridium anodes were fabricated. Testing of electroformed iridium anodes shows no visible degradation. The result of development, manufacturing and testing of high surface, inert iridium anodes will be presented.

Metal-based anode for high performance bioelectrochemical systems through photo-electrochemical interaction

NASA Astrophysics Data System (ADS)

Liang, Yuxiang; Feng, Huajun; Shen, Dongsheng; Long, Yuyang; Li, Na; Zhou, Yuyang; Ying, Xianbin; Gu, Yuan; Wang, Yanfeng

2016-08-01

This paper introduces a novel composite anode that uses light to enhance current generation and accelerate biofilm formation in bioelectrochemical systems. The composite anode is composed of 316L stainless steel substrate and a nanostructured α-Fe2O3 photocatalyst (PSS). The electrode properties, current generation, and biofilm properties of the anode are investigated. In terms of photocurrent, the optimal deposition and heat-treatment times are found to be 30 min and 2 min, respectively, which result in a maximum photocurrent of 0.6 A m-2. The start-up time of the PSS is 1.2 days and the maximum current density is 2.8 A m-2, twice and 25 times that of unmodified anode, respectively. The current density of the PSS remains stable during 20 days of illumination. Confocal laser scanning microscope images show that the PSS could benefit biofilm formation, while electrochemical impedance spectroscopy indicates that the PSS reduce the charge-transfer resistance of the anode. Our findings show that photo-electrochemical interaction is a promising way to enhance the biocompatibility of metal anodes for bioelectrochemical systems.

Mussel-Inspired Conductive Polymer Binder for Si-Alloy Anode in Lithium-Ion Batteries

DOE PAGES

Zhao, Hui; Wei, Yang; Wang, Cheng; ...

2018-01-15

The excessive volume changes during cell cycling of Si-based anode in lithium ion batteries impeded its application. One major reason for the cell failure is particle isolation during volume shrinkage in delithiation process, which makes strong adhesion between polymer binder and anode active material particles a highly desirable property. Here, a biomimetic side-chain conductive polymer incorporating catechol, a key adhesive component of the mussel holdfast protein, was synthesized. Atomic force microscopy-based single-molecule force measurements of mussel-inspired conductive polymer binder contacting a silica surface revealed a similar adhesion toward substrate when compared with an effective Si anode binder, homo-poly(acrylic acid), withmore » the added benefit of being electronically conductive. Electrochemical experiments showed a very stable cycling of Si-alloy anodes realized via this biomimetic conducting polymer binder, leading to a high loading Si anode with a good rate performance. We attribute the ability of the Si-based anode to tolerate the volume changes during cycling to the excellent mechanical integrity afforded by the strong interfacial adhesion of the biomimetic conducting polymer.« less

A comparison between DART-MS and DSA-MS in the forensic analysis of writing inks.

PubMed

Drury, Nicholas; Ramotowski, Robert; Moini, Mehdi

2018-05-23

Ambient ionization mass spectrometry is gaining momentum in forensic science laboratories because of its high speed of analysis, minimal sample preparation, and information-rich results. One such application of ambient ionization methodology includes the analysis of writing inks from questioned documents where colorants of interest may not be soluble in common solvents, rendering thin layer chromatography (TLC) and separation-mass spectrometry methods such as LC/MS (-MS) impractical. Ambient ionization mass spectrometry uses a variety of ionization techniques such as penning ionization in Direct Analysis in Real Time (DART), and atmospheric pressure chemical ionization in Direct Sample Analysis (DSA), and electrospray ionization in Desorption Electrospray Ionization (DESI). In this manuscript, two of the commonly used ambient ionization techniques are compared: Perkin Elmer DSA-MS and IonSense DART in conjunction with a JEOL AccuTOF MS. Both technologies were equally successful in analyzing writing inks and produced similar spectra. DSA-MS produced less background signal likely because of its closed source configuration; however, the open source configuration of DART-MS provided more flexibility for sample positioning for optimum sensitivity and thereby allowing smaller piece of paper containing writing ink to be analyzed. Under these conditions, the minimum sample required for DART-MS was 1mm strokes of ink on paper, whereas DSA-MS required a minimum of 3mm. Moreover, both techniques showed comparable repeatability. Evaluation of the analytical figures of merit, including sensitivity, linear dynamic range, and repeatability, for DSA-MS and DART-MS analysis is provided. To the forensic context of the technique, DART-MS was applied to the analysis of United States Secret Service ink samples directly on a sampling mesh, and the results were compared with DSA-MS of the same inks on paper. Unlike analysis using separation mass spectrometry, which requires sample preparation, both DART-MS and DSA-MS successfully analyzed writing inks with minimal sample preparation. Copyright © 2018 Elsevier B.V. All rights reserved.

Comparison of hepatic MDCT, MRI, and DSA to explant pathology for the detection and treatment planning of hepatocellular carcinoma.

PubMed

Ladd, Lauren M; Tirkes, Temel; Tann, Mark; Agarwal, David M; Johnson, Matthew S; Tahir, Bilal; Sandrasegaran, Kumaresan

2016-12-01

The diagnosis and treatment plan for hepatocellular carcinoma (HCC) can be made from radiologic imaging. However, lesion detection may vary depending on the imaging modality. This study aims to evaluate the sensitivities of hepatic multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and digital subtraction angiography (DSA) in the detection of HCC and the consequent management impact on potential liver transplant patients. One hundred and sixteen HCC lesions were analyzed in 41 patients who received an orthotopic liver transplant (OLT). All of the patients underwent pretransplantation hepatic DSA, MDCT, and/or MRI. The imaging results were independently reviewed retrospectively in a blinded fashion by two interventional and two abdominal radiologists. The liver explant pathology was used as the gold standard for assessing each imaging modality. The sensitivity for overall HCC detection was higher for cross-sectional imaging using MRI (51.5%, 95% confidence interval [CI]=36.2-58.4%) and MDCT (49.8%, 95% CI=43.7-55.9%) than for DSA (41.7%, 95% CI=36.2-47.3%) ( P =0.05). The difference in false-positive rate was not statistically significant between MRI (22%), MDCT (29%), and DSA (29%) ( P =0.67). The sensitivity was significantly higher for detecting right lobe lesions than left lobe lesions for all modalities (MRI: 56.1% vs. 43.1%, MDCT: 55.0% vs. 42.0%, and DSA: 46.9% vs. 33.9%; all P <0.01). The sensitivities of the three imaging modalities were also higher for lesions ≥2 cm vs. <2 cm (MRI: 73.4% vs. 32.7%, MDCT: 66.9% vs. 33.8%, and DSA: 62.2% vs. 24.1%; all P <0.01). The interobserver correlation was rated as very good to excellent. The sensitivity for detecting HCC is higher for MRI and MDCT than for DSA, and so cross-sectional imaging modalities should be used to evaluate OLT candidacy.

A safe and effective management strategy for blunt cerebrovascular injury: Avoiding unnecessary anticoagulation and eliminating stroke.

PubMed

Shahan, Charles P; Magnotti, Louis J; Stickley, Shaun M; Weinberg, Jordan A; Hendrick, Leah E; Uhlmann, Rebecca A; Schroeppel, Thomas J; Hoit, Daniel A; Croce, Martin A; Fabian, Timothy C

2016-06-01

Few injuries have produced as much debate with respect to management as have blunt cerebrovascular injuries (BCVIs). Recent work (American Association for the Surgery of Trauma 2013) from our institution suggested that 64-channel multidetector computed tomographic angiography (CTA) could be the primary screening tool for BCVI. Consequently, our screening algorithm changed from digital subtraction angiography (DSA) to CTA, with DSA reserved for definitive diagnosis of BCVI following CTA-positive study results or unexplained neurologic findings. The current study was performed to evaluate outcomes, including the potential for missed clinically significant BCVI, since this new management algorithm was adopted. Patients who underwent DSA (positive CTA finding or unexplained neurologic finding) over an 18-month period subsequent to the previous study were identified. Screening and confirmatory test results, complications, and BCVI-related strokes were reviewed and compared. A total of 228 patients underwent DSA: 64% were male, with mean age and Injury Severity Score (ISS) of 43 years and 22, respectively. A total of 189 patients (83%) had a positive screening CTA result. Of these, DSA confirmed injury in 104 patients (55%); the remaining 85 patients (45%) (false-positive results) were found to have no injury on DSA. Five patients (4.8%) experienced BCVI-related strokes, unchanged from the previous study (3.9%, p = 0.756); two were symptomatic at trauma center presentation, and three occurred while receiving appropriate therapy. No patient with a negative screening CTA result experienced a stroke. This management scheme using 64-channel CTA for screening coupled with DSA for definitive diagnosis was proven to be safe and effective in identifying clinically significant BCVIs and maintaining a low stroke rate. Definitive diagnosis by DSA led to avoidance of potentially harmful anticoagulation in 45% of CTA-positive patients (false-positive results). No strokes resulted from injuries missed by CTA. Diagnostic study, level III.

2012 annual literature review of donor-specific HLA antibodies after organ transplantation.

PubMed

Kaneku, Hugo

2012-01-01

From the articles reviewed in the present chapter, we observed: 1. The frequency of de novo donor-specific human leukocyte antigen (HLA) antibodies (DSA) detection in different organs is very similar: ranging between 15% and 23% in kidney, 23% in pancreas, and 18% in intestinal transplant patients. Apparently, all organs can elicit humoral responses after transplantation at comparable rates. 2. Although rates of de novo DSA formation after kidney transplantation are very similar across different centers--between 15% and 23%--, the mean time to the first detection of de novo DSA is markedly variable between centers (from 8 months to 4 years). Some differences found in the studies that may account for this could be the age of patients (studies including pediatric patients tend to show longer time to DSA detection compared to studies only including adults patients), patients' race, and maintenance immunosuppression regimens. 3. In most organs, alloantibodies against class II HLA--and especially against HLA-DQ antigens--are the most common DSA detected. This finding supports previous studies, but the explanation remains unclear. Poor HLA-DQ matching, paucity of class II HLA antigen expression on cell surface, and technical factors related to the detection of these antibodies (mean fluorescence intensity cutoff, multiple beads with the same antigen, denatured protein on single antigen beads) are some of the potential explanations that need further investigation. 4. Recent focus on histological changes during rejection in the presence of DSA that are independent of C4d deposition may change how antibody-mediated rejection is diagnosed in the near future. 5. More studies are looking into the importance of DSA in non-kidney transplants and now evidence shows that DSA may not only affect survival and rejection rates, but may also be associated with organ-specific lesions like fibrosis and biliary complications in livers or capillaritis in lungs.

A Highly Controllable Electrochemical Anodization Process to Fabricate Porous Anodic Aluminum Oxide Membranes

NASA Astrophysics Data System (ADS)

Lin, Yuanjing; Lin, Qingfeng; Liu, Xue; Gao, Yuan; He, Jin; Wang, Wenli; Fan, Zhiyong

2015-12-01

Due to the broad applications of porous alumina nanostructures, research on fabrication of anodized aluminum oxide (AAO) with nanoporous structure has triggered enormous attention. While fabrication of highly ordered nanoporous AAO with tunable geometric features has been widely reported, it is known that its growth rate can be easily affected by the fluctuation of process conditions such as acid concentration and temperature during electrochemical anodization process. To fabricate AAO with various geometric parameters, particularly, to realize precise control over pore depth for scientific research and commercial applications, a controllable fabrication process is essential. In this work, we revealed a linear correlation between the integrated electric charge flow throughout the circuit in the stable anodization process and the growth thickness of AAO membranes. With this understanding, we developed a facile approach to precisely control the growth process of the membranes. It was found that this approach is applicable in a large voltage range, and it may be extended to anodization of other metal materials such as Ti as well.

A Highly Controllable Electrochemical Anodization Process to Fabricate Porous Anodic Aluminum Oxide Membranes.

PubMed

Lin, Yuanjing; Lin, Qingfeng; Liu, Xue; Gao, Yuan; He, Jin; Wang, Wenli; Fan, Zhiyong

2015-12-01

Due to the broad applications of porous alumina nanostructures, research on fabrication of anodized aluminum oxide (AAO) with nanoporous structure has triggered enormous attention. While fabrication of highly ordered nanoporous AAO with tunable geometric features has been widely reported, it is known that its growth rate can be easily affected by the fluctuation of process conditions such as acid concentration and temperature during electrochemical anodization process. To fabricate AAO with various geometric parameters, particularly, to realize precise control over pore depth for scientific research and commercial applications, a controllable fabrication process is essential. In this work, we revealed a linear correlation between the integrated electric charge flow throughout the circuit in the stable anodization process and the growth thickness of AAO membranes. With this understanding, we developed a facile approach to precisely control the growth process of the membranes. It was found that this approach is applicable in a large voltage range, and it may be extended to anodization of other metal materials such as Ti as well.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Hui; Wei, Yang; Wang, Cheng

The excessive volume changes during cell cycling of Si-based anode in lithium ion batteries impeded its application. One major reason for the cell failure is particle isolation during volume shrinkage in delithiation process, which makes strong adhesion between polymer binder and anode active material particles a highly desirable property. Here, a biomimetic side-chain conductive polymer incorporating catechol, a key adhesive component of the mussel holdfast protein, was synthesized. Atomic force microscopy-based single-molecule force measurements of mussel-inspired conductive polymer binder contacting a silica surface revealed a similar adhesion toward substrate when compared with an effective Si anode binder, homo-poly(acrylic acid), withmore » the added benefit of being electronically conductive. Electrochemical experiments showed a very stable cycling of Si-alloy anodes realized via this biomimetic conducting polymer binder, leading to a high loading Si anode with a good rate performance. We attribute the ability of the Si-based anode to tolerate the volume changes during cycling to the excellent mechanical integrity afforded by the strong interfacial adhesion of the biomimetic conducting polymer.« less

New insight into the discharge mechanism of silicon-air batteries using electrochemical impedance spectroscopy.

PubMed

Cohn, Gil; Eichel, Rüdiger A; Ein-Eli, Yair

2013-03-07

The mechanism of discharge termination in silicon-air batteries, employing a silicon wafer anode, a room-temperature fluorohydrogenate ionic liquid electrolyte and an air cathode membrane, is investigated using a wide range of tools. EIS studies indicate that the interfacial impedance between the electrolyte and the silicon wafer increases upon continuous discharge. In addition, it is shown that the impedance of the air cathode-electrolyte interface is several orders of magnitude lower than that of the anode. Equivalent circuit fitting parameters indicate the difference in the anode-electrolyte interface characteristics for different types of silicon wafers. Evolution of porous silicon surfaces at the anode and their properties, by means of estimated circuit parameters, is also presented. Moreover, it is found that the silicon anode potential has the highest negative impact on the battery discharge voltage, while the air cathode potential is actually stable and invariable along the whole discharge period. The discharge capacity of the battery can be increased significantly by mechanically replacing the silicon anode.

Porous carbon-free SnSb anodes for high-performance Na-ion batteries

NASA Astrophysics Data System (ADS)

Choi, Jeong-Hee; Ha, Choong-Wan; Choi, Hae-Young; Seong, Jae-Wook; Park, Cheol-Min; Lee, Sang-Min

2018-05-01

A simple melt-spinning/chemical-etching process is developed to create porous carbon-free SnSb anodes. Sodium ion batteries (SIBs) incorporating these anodes exhibit excellent electrochemical performances by accomodating large volume changes during repeated cycling. The porous carbon-free SnSb anode produced by the melt-spinning/chemical-etching process shows a high reversible capacity of 481 mAh g-1, high ICE of 80%, stable cyclability with a high capacity retention of 99% after 100 cycles, and a fast rate capability of 327 mAh g-1 at 4C-rate. Ex-situ X-ray diffraction and high resolution-transmission electron microscopy analyses demonstrate that the synthesized porous carbon-free SnSb anodes involve the highly reversible reaction with sodium through the conversion and recombination reactions during sodiation/desodiation process. The novel and simple melt-spinning/chemical-etching synthetic process represents a technological breakthrough in the commercialization of Na alloy-able anodes for SIBs.

Engineering Hollow Carbon Architecture for High-Performance K-Ion Battery Anode.

PubMed

Bin, De-Shan; Lin, Xi-Jie; Sun, Yong-Gang; Xu, Yan-Song; Zhang, Ke; Cao, An-Min; Wan, Li-Jun

2018-05-31

K-ion batteries (KIBs) are now drawing increasing research interest as an inexpensive alternative to Li-ion batteries (LIBs). However, due to the large size of K + , stable electrode materials capable of sustaining the repeated K + intercalation/deintercalation cycles are extremely deficient especially if a satisfactory reversible capacity is expected. Herein, we demonstrated that the structural engineering of carbon into a hollow interconnected architecture, a shape similar to the neuron-cell network, promised high conceptual and technological potential for a high-performance KIB anode. Using melamine-formaldehyde resin as the starting material, we identify an interesting glass blowing effect of this polymeric precursor during its carbonization, which features a skeleton-softening process followed by its spontaneous hollowing. When used as a KIB anode, the carbon scaffold with interconnected hollow channels can ensure a resilient structure for a stable potassiation/depotassiation process and deliver an extraordinary capacity (340 mAh g -1 at 0.1 C) together with a superior cycling stability (no obvious fading over 150 cycles at 0.5 C).

Highly stable carbon coated Mg2Si intermetallic nanoparticles for lithium-ion battery anode

NASA Astrophysics Data System (ADS)

Tamirat, Andebet Gedamu; Hou, Mengyan; Liu, Yao; Bin, Duan; Sun, Yunhe; Fan, Long; Wang, Yonggang; Xia, Yongyao

2018-04-01

Silicon is an ideal candidate anode material for Li-ion batteries (LIBs). However, it suffers from rapid capacity fading due to large volume expansion upon lithium insertion. Herein, we design and fabricate highly stable carbon coated porous Mg2Si intermetallic anode material using facile mechano-thermal technique followed by carbon coating using thermal vapour deposition (TVD), toluene as carbon source. The electrode exhibits an excellent first reversible capacity of 726 mAh g-1 at a rate of 100 mA g-1. More importantly, the electrode demonstrates high rate capability (380 mAh g-1 at high rate of 2 A g-1) as well as high cycle stability, with capacity retentions of 65% over 500 cycles. These improvements are attributable to both Mg supporting medium and the uniform carbon coating, which can effectively increase the conductivity and electronic contact of the active material and protects large volume alterations during the electrochemical cycling process.

Electrochemical membrane incinerator

DOEpatents

Johnson, Dennis C.; Houk, Linda L.; Feng, Jianren

2001-03-20

Electrochemical incineration of p-benzoquinone was evaluated as a model for the mineralization of carbon in toxic aromatic compounds. A Ti or Pt anode was coated with a film of the oxides of Ti, Ru, Sn and Sb. This quaternary metal oxide film was stable; elemental analysis of the electrolyzed solution indicated the concentration of these metal ions to be 3 .mu.g/L or less. The anode showed good reactivity for the electrochemical incineration of benzoquinone. The use of a dissolved salt matrix as the so-called "supporting electrolyte" was eliminated in favor of a solid-state electrolyte sandwiched between the anode and cathode.

In situ fabrication of high-performance Ni-GDC-nanocube core-shell anode for low-temperature solid-oxide fuel cells

PubMed Central

Yamamoto, Kazuhiro; Qiu, Nan; Ohara, Satoshi

2015-01-01

A core–shell anode consisting of nickel–gadolinium-doped-ceria (Ni–GDC) nanocubes was directly fabricated by a chemical process in a solution containing a nickel source and GDC nanocubes covered with highly reactive {001} facets. The cermet anode effectively generated a Ni metal framework even at 500 °C with the growth of the Ni spheres. Anode fabrication at such a low temperature without any sintering could insert a finely nanostructured layer close to the interface between the electrolyte and the anode. The maximum power density of the attractive anode was 97 mW cm–2, which is higher than that of a conventional NiO–GDC anode prepared by an aerosol process at 55 mW cm–2 and 600 °C, followed by sintering at 1300 °C. Furthermore, the macro- and microstructure of the Ni–GDC-nanocube anode were preserved before and after the power-generation test at 700 °C. Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully. PMID:26615816

Novel approaches for fabrication of thin film layers for solid oxide electrolyte fuel cells

NASA Technical Reports Server (NTRS)

Murugesamoorthi, K. A.; Srinivasan, S.; Cocke, D. L.; Appleby, A. J.

1990-01-01

The main objectives of the SOFC (solid oxide fuel cell) project are to (1) identify viable and cost-effective techniques to prepare cell components for stable MSOFCs (monolithic SOFCs); (2) fabricate half and single cells; and (3) evaluate their performances. The approach used to fabricate stable MSOFCs is as follows: (1) the electrolyte layer is prepared in the form of a honeycomb structure by alloy oxidation and other cell components are deposited on it; (2) the electrolyte and anode layers are deposited on the cathode layer, which has a porous, honeycomb structure; and (3) the electrolyte and cathode layers are deposited on the anode layer. The current status of the project is reported.

Supported plasma sputtering apparatus for high deposition rate over large area

DOEpatents

Moss, Ronald W.; McClanahan, Jr., Edwin D.; Laegreid, Nils

1977-01-01

A supported plasma sputtering apparatus is described having shaped electrical fields in the electron discharge region between the cathode and anode and the sputter region between the target and substrate while such regions are free of any externally applied magnetic field to provide a high deposition rate which is substantially uniform over a wide area. Plasma shaping electrodes separate from the anode and target shape the electrical fields in the electron discharge region and the sputter region to provide a high density plasma. The anode surrounds the target to cause substantially uniform sputtering over a large target area. In one embodiment the anode is in the form of an annular ring surrounding a flat target surface, such anode being provided with a ribbed upper surface which shields portions of the anode from exposure to sputtered material to maintain the electron discharge for a long stable operation. Several other embodiments accomplish the same result by using different anodes which either shield the anode from sputtered material, remove the sputtered coating on the anode by heating, or simultaneously mix sputtered metal from the auxiliary target with sputtered insulator from the main target so the resultant coating is conductive. A radio frequency potential alone or together with a D.C. potential, may be applied to the target for a greater sputtering rate.

Combined carbon mesh and small graphite fiber brush anodes to enhance and stabilize power generation in microbial fuel cells treating domestic wastewater

NASA Astrophysics Data System (ADS)

Wu, Shijia; He, Weihua; Yang, Wulin; Ye, Yaoli; Huang, Xia; Logan, Bruce E.

2017-07-01

Microbial fuel cells (MFCs) need to have a compact architecture, but power generation using low strength domestic wastewater is unstable for closely-spaced electrode designs using thin anodes (flat mesh or small diameter graphite fiber brushes) due to oxygen crossover from the cathode. A composite anode configuration was developed to improve performance, by joining the mesh and brushes together, with the mesh used to block oxygen crossover to the brushes, and the brushes used to stabilize mesh potentials. In small, fed-batch MFCs (28 mL), the composite anode produced 20% higher power densities than MFCs using only brushes, and 150% power densities compared to carbon mesh anodes. In continuous flow tests at short hydraulic retention times (HRTs, 2 or 4 h) using larger MFCs (100 mL), composite anodes had stable performance, while brush anode MFCs exhibited power overshoot in polarization tests. Both configurations exhibited power overshoot at a longer HRT of 8 h due to lower effluent CODs. The use of composite anodes reduced biomass growth on the cathode (1.9 ± 0.2 mg) compared to only brushes (3.1 ± 0.3 mg), and increased coulombic efficiencies, demonstrating that they successfully reduced oxygen contamination of the anode and the bio-fouling of cathode.

Dark Skies Awareness Cornerstone Project for the International Year of Astronomy

NASA Astrophysics Data System (ADS)

Walker, C. E.; Pompea, S. M.; Iya Dark Skies Awareness Working Group

2010-12-01

Programs that were part of the International Year of Astronomy 2009 (IYA2009) Dark Skies Awareness (DSA) Cornerstone Project have been successfully implemented around the world to promote social awareness of the effects of light pollution on public health, economic issues, ecological consequences, energy conservation, safety and security, nightscape aesthetics and especially astronomy. In developing the programs, DSA Cornerstone Project found that to influence cultural change effectively — to make people literally look up and see the light — we must make children a main focus, use approaches that offer involvement on many levels, from cursory to committed, and offer involvement via many venues. We must make the programs and resources as turn-key as possible, especially for educators — and provide ways to visualize the problem with simple, easily grasped demonstrations. The programs spanned a wide range; from new media technology for the younger generation, to an event in the arts, to various types of educational materials, to the promotion of dark skies communities, to national and international events and to global citizen science programs. The DSA Cornerstone Project is continuing most all of these programs beyond IYA2009. The International Dark-Sky Association as well as the Starlight Initiative is endorsing and helping to continue with some of the most successful programs from the DSA. The GLOBE at Night campaign is adding a research component that examines light pollution’s affects on wildlife. Dark Skies Rangers activities are being implemented in Europe through the Galileo Teacher Training Program. The new “One Star at a Time” will engage people to protect the night sky through personal pledges and registration of public stargazing areas or StarParks, like the newest one in Italy. The Starlight Initiative’s World Night in Defence of the Starlight will take place on the Vernal Equinox. DSA will again oversee the Dark Skies portion of Global Astronomy Month, in which the International Dark Sky Week will be celebrated. DSA will be collaborating with Belgium’s “Night of Darkness” to endeavor to make that lights out event a more global event. DSA will endeavor to support dark skies education worldwide, as in Northern Ireland. DSA will seek to expand light pollution prevention campaigns like Austria’s. People whose homes meet the criteria of good lighting are invited to put a sticker from Austria’s biggest newspaper in their front window to show their support. DSA also seeks to collaborate with the IAU Office for Astronomy Development. The presentation will focus on the DSA programs during IYA and the sustainability of the DSA programs after IYA, as well as the expansion to other programs worldwide, with particular emphasis in communicating dark skies awareness with the public and its educational value in attracting young people to study science and technology. See www.darkskiesawareness.org for more information on the programs.

Effect of the Anion Activity on the Stability of Li Metal Anodes in Lithium-Sulfur Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Ruiguo; Chen, Junzheng; Han, Kee Sung

2016-03-29

With the significant progress made in the development of cathodes in lithium-sulfur (Li-S) batteries, the stability of Li metal anodes becomes a more urgent challenge in these batteries. Here we report the systematic investigation of the stability of the anode/electrolyte interface in Li-S batteries with concentrated electrolytes containing various lithium salts. It is found that Li-S batteries using LiTFSI-based electrolytes are more stable than those using LiFSI-based electrolytes. The decreased stability is because the N-S bond in the FSI- anion is fairly weak and the scission of this bond leads to the formation of lithium sulfate (LiSOx) in the presencemore » of polysulfide species. In contrast, even the weakest bond (C-S) in the TFSI- anion is stronger than the N-S bond in the FSI- anion. In the LiTFSI-based electrolyte, the lithium metal anode tends to react with polysulfide to form lithium sulfide (LiSx) which is more reversible than LiSOx formed in the LiTFSI-based electrolyte. This fundamental difference in the bond strength of the salt anions in the presence of polysulfide species leads to a large difference in the stability of the anode-electrolyte interface and performance of the Li-S batteries with electrolytes composed of these salts. Therefore, anion selection is one of the key parameters in the search for new electrolytes for stable operation of Li-S batteries.« less

Space Environmental Effects on Colored Coatings and Anodizes

NASA Technical Reports Server (NTRS)

Kamenetzky, Rachel R.; Finckenor, Miria M.; Vaughn, Jason A.

1999-01-01

Colored coatings and anodizes are used on spacecraft as markers and astronaut visual aids. These materials must be stable in the space environment and withstand atomic oxygen, ultraviolet radiation, particulate radiation, thermal cycling, and high vacuum without significant change in optical and mechanical properties. A variety of colored coatings and anodizes have been exposed to simulated space environments at Marshall Space Flight Center and also actual space environment as part of the Passive Optical Sample Assembly (POSA) - I flight experiment. Colored coatings were developed by AZ Technology, Huntsville, AL, under a NASA contract for International Space Station (ISS). These include yellow, red, blue, and black paints suitable for Extra-Vehicular Activity (EVA) visual aids and ISS emblems. AaChron, Inc., Minneapolis, MN, developed stable colored anodizes, also in yellow, red, blue, and black, for astronaut visual aids. These coatings were exposed in the laboratory to approximately 550 equivalent sun-hours of solar ultraviolet radiation and approximately 1 x 10(exp 21) atoms/sq cm of atomic oxygen in vacuum. The AZ Technology yellow colored coating, designated TMS800IY, and all four AaChron colored anodizes were flown on POSA-I. POSA-I was a Risk Mitigation Experiment for ISS. It was attached to the exterior of the Mir space station docking module by EVA and was exposed for 18 months. The laboratory-simulated space environment, the natural space environment and the unique environment of an orbiting, active space station and their effects on these developmental materials are discussed.

Enhanced performance of graphite anode materials by AlF3 coating for lithium-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Xu, Wu; Choi, Daiwon

2012-04-27

In order to form the stable surface film and to further enhance the long-term cycling stability of the graphite anodes of lithium-ion batteries, the surface of graphite powders has been modified by AlF3 coating through chemical precipitation method. The AlF3-coated graphite shows no evident changes in the bulk structure and a thin AlF3-coating layer of about 2 nm thick is found to uniformly cover the graphite particles with 2 wt% AlF3 content. However, it delivers a higher initial discharge capacity and largely improved rate performances compared to the pristine graphite. Remarkably, AlF3 coated graphite demonstrated a much better cycle life.more » After 300 cycles, AlF3 coated graphite and uncoated graphite show capacity retention of 92% and 81%, respectively. XPS measurement shows that a more conductive solid electrode interface (SEI) layer was formed on AlF3 coated graphite as compared to uncoated graphite. SEM monograph also reveals that the AlF3-coated graphite particles have a much more stable surface morphology after long-term cycling. Therefore, the improved electrochemical performance of AlF3 coated graphite can be attributed to a more stable and conductive SEI formed on coated graphite anode during cycling process.« less

Alternative Anodes for the Electrolytic Reduction of Uranium Dioxide

NASA Astrophysics Data System (ADS)

Merwin, Augustus

Reprocessing of spent nuclear fuel is an essential step in closing the nuclear fuel cycle. In order to consume current stockpiles, ceramic uranium dioxide spent nuclear fuel will be subjected to an electrolytic reduction process. The current reduction process employs a platinum anode and a stainless steel alloy 316 cathode in a molten salt bath consisting of LiCl-2wt% Li 2O and occurs at 700°C. A major shortcoming of the existing process is the degradation of the platinum anode under the severely oxidizing conditions encountered during electrolytic reduction. This work investigates alternative anode materials for the electrolytic reduction of uranium oxide. The high temperature and extreme oxidizing conditions encountered in these studies necessitated a unique set of design constraints on the system. Thus, a customized experimental apparatus was designed and constructed. The electrochemical experiments were performed in an electrochemical reactor placed inside a furnace. This entire setup was housed inside a glove box, in order to maintain an inert atmosphere. This study investigates alternative anode materials through accelerated corrosion testing. Surface morphology was studied using scanning electron microscopy. Surface chemistry was characterized using energy dispersive spectroscopy and Raman spectroscopy. Electrochemical behavior of candidate materials was evaluated using potentiodynamic polarization characteristics. After narrowing the number of candidate electrode materials, ferrous stainless steel alloy 316, nickel based Inconel 718 and elemental tungsten were chosen for further investigation. Of these materials only tungsten was found to be sufficiently stable at the anodic potential required for electrolysis of uranium dioxide in molten salt. The tungsten anode and stainless steel alloy 316 cathode electrode system was studied at the required reduction potential for UO2 with varying lithium oxide concentrations. Electrochemical impedance spectroscopy showed mixed (kinetic and diffusion) control and an overall low impedance due to extreme corrosion. It was observed that tungsten is sufficiently stable in LiCl - 2wt% Li 2O at 700°C at the required anodic potential for the reduction of uranium oxide. This study identifies tungsten to be a superior anode material to platinum for the electrolytic reduction of uranium oxide, both in terms of superior corrosion behavior and reduced cost, and thus recommends that tungsten be further investigated as an alternative anode for the electrolytic reduction of uranium dioxide.

A retrospective analysis of environmental risk factors for the diagnosis of deep stromal abscess in 390 horses in North Central Florida from 1991 to 2013.

PubMed

Proietto, Laura R; Plummer, Caryn E; Maxwell, Kathleen M; Lamb, Kenneth E; Brooks, Dennis E

2016-07-01

The purpose of this investigation was to identify potential environmental risk factors for the diagnosis of equine deep stromal abscesses (DSA) in the subtropical climate at the University of Florida Veterinary Medical Center (UFVMC). Cases included were selected from the UFVMC medical record and imaging database, and included all cases of equine DSA diagnosed during the period from December 1991 to December 2013 in patients residing in north central Florida. Patient date of diagnosis and atmospheric data was obtained for north central Florida for the corresponding time period. Univariate and multivariate general linear models were generated testing effects and interactions between environmental conditions. When year, sulfur dioxide (SO2 ) and wind were analyzed in the presence of each other, a one-mile per hour increase in wind (P = 0.005) significantly increased the number of DSA cases by 1.63 cases per year. When the influence of temperature was evaluated in conjunction with year and nitrogen dioxide (NO2 ), the number of cases decreased by 0.1534 per year for every degree increase in temperature (°C) (P = 0.039). Wind speed is the first significant atmospheric risk factor to be identified for DSA formation in the horse. The importance of environmental variance in the incidence of DSA indicates that the pathogenesis of DSA formation may be multifactorial, interdependent and provides support in some horses for the micropuncture hypothesis of DSA formation related to the involvement of environmental conditions causing precorneal tear film and epithelial damage. © 2015 American College of Veterinary Ophthalmologists.

Flat-detector computed tomography evaluation in an experimental animal aneurysm model after endovascular treatment: A pilot study.

PubMed

Ott, Sabine; Gölitz, Philipp; Adamek, Edyta; Royalty, Kevin; Doerfler, Arnd; Struffert, Tobias

2015-08-01

We compared flat-detector computed tomography angiography (FD-CTA) to multislice computed tomography (MS-CTA) and digital subtracted angiography (DSA) for the visualization of experimental aneurysms treated with stents, coils or a combination of both.In 20 rabbits, aneurysms were created using the rabbit elastase aneurysm model. Seven aneurysms were treated with coils, seven with coils and stents, and six with self-expandable stents alone. Imaging was performed by DSA, MS-CTA and FD-CTA immediately after treatment. Multiplanar reconstruction (MPR) was performed and two experienced reviewers compared aneurysm/coil package size, aneurysm occlusion, stent diameters and artifacts for each modality.In aneurysms treated with stents alone, the visualization of the aneurysms was identical in all three imaging modalities. Residual aneurysm perfusion was present in two cases and visible in DSA and FD-CTA but not in MS-CTA. The diameter of coil-packages was overestimated in MS-CT by 56% and only by 16% in FD-CTA compared to DSA (p < 0.05). The diameter of stents was identical for DSA and FD-CTA and was significantly overestimated in MS-CTA (p < 0.05). Beam/metal hardening artifacts impaired image quality more severely in MS-CTA compared to FD-CTA.MS-CTA is impaired by blooming and beam/metal hardening artifacts in the visualization of implanted devices. There was no significant difference between measurements made with noninvasive FD-CTA compared to gold standard of DSA after stenting and after coiling/stent-assisted coiling of aneurysms. FD-CTA may be considered as a non-invasive alternative to the gold standard 2D DSA in selected patients that require follow up imaging after stenting. © The Author(s) 2015.

Voluntary Exercise Impairs Initial Delayed Spatial Alternation Performance in Estradiol Treated Ovariectomized Middle-Aged Rats

PubMed Central

Neese, Steven L.; Korol, Donna L.; Schantz, Susan L.

2013-01-01

Estrogens differentially modulate behavior in the adult female rodent. Voluntary exercise can also impact behavior, often reversing age associated decrements in memory processes. Our research group has published a series of papers reporting a deficit in the acquisition of an operant working memory task, delayed spatial alternation (DSA), following 17β-estradiol treatment to middle-aged ovariectomized (OVX) rats. The current study examined if voluntary exercise could attenuate the 17β-estradiol induced deficits on DSA performance. OVX 12-month old Long- Evans rats were implanted with a Silastic capsule containing 17β-estradiol (10% in cholesterol: low physiological range) or with a blank capsule. A subset of the 17β-estradiol and OVX untreated rats were given free access to a running wheel in their home cage. All rats were tested for 40 sessions on the DSA task. Surprisingly, we found running wheel access to impair initial acquisition of the DSA task in 17β-estradiol treated rats, an effect not seen in OVX untreated rats given running wheel access. This deficit was driven by an increase in perseverative responding on a lever no longer associated with reinforcement. We also report for the first time a 17β-estradiol induced impairment on the DSA task following a long intertrial delay (18-sec), an effect revealed following more extended testing than in our previous studies (15 additional sessions). Overall, running wheel access increased initial error rate on the DSA task in 17β-estradiol treated middle-aged OVX rats, and failed to prevent the 17β-estradiol induced deficits in performance of the operant DSA task in later testing sessions. PMID:24013039

Automated carbon dioxide digital angiography for lower-limb arterial disease evaluation: safety assessment and comparison with standard iodinated contrast media angiography.

PubMed

Scalise, Filippo; Novelli, Eugenio; Auguadro, Carla; Casali, Valentina; Manfredi, Mariella; Zannoli, Romano

2015-01-01

Carbon dioxide (CO2) has been validated as a contrast agent in a large series of studies. A particular advantages of CO2 over iodinated contrast medium (ICM) is the absence of nephrotoxicity and allergic reactions. One of the limitations of CO2 angiography is the difficulty of CO2 manual injection due to its compressibility. The manual gas injection does not permit optimal control of the gas output. Development of an automated CO2 injector has overcome these problems. This study compares the feasibility, safety, and diagnostic accuracy of automated CO2 digital subtraction angiography (DSA) in comparison with ICM-DSA in the evaluation of critical limb ischemic (CLI) patients. We performed DSA with both CO2 and ICM on 40 consecutive CLI patients and directly compared the two techniques. Sixteen females and 24 males participated in the study (mean age, 71.7 years). We assessed the diagnostic accuracy of CO2 in identifying arterial stenosis in the lower limb, with ICM-DSA used as the gold standard. The overall diagnostic accuracy of CO2-DSA was 96.9% (sensitivity, 99.0%; specificity, 96.1%; positive predictive value, 91.1%; negative predictive value, 99.6%). Tolerable minor symptoms occurred in 3 patients. No allergic reactions or significant decline in renal function were observed in patients receiving the CO2 injection. Carbon dioxide DSA is a valuable and safe alternative to traditional ICM-DSA for evaluating CLI patients. This modality should be considered as the standard choice for CLI patients undergoing angiographic evaluation who are known to have renal insufficiency or contrast allergy.

Preoperative assessment of intracranial tumors with perfusion MR and a volumetric interpolated examination: a comparative study with DSA.

PubMed

Wetzel, Stephan G; Cha, Soonmee; Law, Meng; Johnson, Glyn; Golfinos, John; Lee, Peter; Nelson, Peter Kim

2002-01-01

In evaluating intracranial tumors, a safe low-cost alternative that provides information similar to that of digital subtraction angiography (DSA) may be of interest. Our purpose was to determine the utility and limitations of a combined MR protocol in assessing (neo-) vascularity in intracranial tumors and their relation to adjacent vessels and to compare the results with those of DSA. Twenty-two consecutive patients with an intracranial tumor who underwent preoperative stereoscopic DSA were examined with contrast-enhanced dynamic T2*-weighted perfusion MR imaging followed by a T1-weighted three-dimensional (3D) MR study (volumetric interpolated brain examination [VIBE]). The maximum relative cerebral blood volume (rCBV) of the tumor was compared with tumor vascularity at DSA. Critical vessel structures were defined in each patient, and VIBE images of these structures were compared with DSA findings. For full exploitation of the 3D data sets, maximum-intensity projection algorithms reconstructed in real time with any desired volume and orientation were used. Tumor blush scores at DSA were significantly correlated with the rCBV measurements (r = 0.75; P <.01, Spearman rank correlation coefficient). In 17 (77%) patients, VIBE provided all relevant information about the venous system, whereas information about critical arteries were partial in 50% of the cases and not relevant in the other 50%. A fast imaging protocol consisting of perfusion MR imaging and a volumetric MR acquisition provides some of the information about tumor (neo-) vascularity and adjacent vascular anatomy that can be obtained with conventional angiography. However, the MR protocol provides insufficient visualization of distal cerebral arteries.

Stenosis detection in native hemodialysis fistulas with MDCT angiography.

PubMed

Heye, Sam; Maleux, Geert; Claes, Kathleen; Kuypers, Dirk; Oyen, Raymond

2009-04-01

The objective of our study was to assess the diagnostic value of 64-MDCT angiography in the evaluation of failing hemodialysis arteriovenous fistulas (AVFs) in comparison with conventional digital subtraction angiography (DSA). Thirty-six patients (22 men; mean age +/- SD, 65 +/- 15 years) with hemodialysis fistula dysfunction underwent MDCT angiography before DSA. Linear weighted kappa was used to calculate interobserver agreement for stenosis for both MDCT angiography and DSA on a 5-point scale. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the detection of >/= 50% stenosis or occlusion on MDCT angiography was calculated using DSA as the standard of reference. Wilcoxon's signed rank test and Mann-Whitney U test were used to compare differences in image quality between MDCT angiography and DSA and between MDCT angiography with the patient's arm stretched overhead or alongside the body, respectively. Interobserver agreement for detecting stenosis was excellent for both DSA (kappa = 0.86; 95% CI, 0.81-0.91) and MDCT angiography (kappa = 0.82; 95% CI, 0.77-0.87). Accuracy, sensitivity, specificity, PPV, and NPV of MDCT angiography for detecting >/= 50% stenosis or occlusion was 92.0% (95% CI, 86.8-95.3%), 90.2% (77.8-96.3%), 92.8% (85.9-96.6%), 85.2% (72.3-92.9%), and 95.4% (89.0-98.3%), respectively. No significant difference in image quality was seen between MDCT angiography and DSA (p = 0.3008) or between MDCT angiography with the patient's arm stretched overhead or alongside the body (p = 0.2912). MDCT angiography is a reproducible and reliable imaging technique for detection of >/= 50% stenosis or occlusion in dysfunctional hemodialysis fistulas.

Magnetic resonance imaging of pseudotumors of the craniovertebral junction in long-term hemodialysis patients.

PubMed

Maruyama, H; Tanizawa, T; Uchiyama, S; Higuchi, T; Ei, K; Oda, M; Ei, I; Oya, M; Kishimoto, H; Saito, T; Miyamura, S; Takano, Y; Hasegawa, S; Kawada, K; Ueki, K; Iwafuchi, Y; Arakawa, M

1999-01-01

Pseudotumors of the craniovertebral junction (PTCVJ) are observed in long-term hemodialysis (HD) patients. There are neither criteria for diagnosis nor guidelines for screening. We attempted to determine magnetic resonance imaging (MRI) findings that could be used to detect PTCVJ, to determine the prevalence of PTCVJ, and to evaluate whether destructive spondyloarthropathy (DSA) might be a yardstick for selection of patients for MRI examination for PTCVJ. MRI were examined in 19 DSA patients (8 males, 11 females, age 61.4 +/- 7.3 years, HD duration 17.0 +/- 4.4 years) and in 20 sex-, age-, and HD-duration-matched non-DSA patients (9 males, 11 females, age 57.5 +/- 6.6 years, HD duration 17.7 +/- 4.9 years). We evaluated MRI characteristics of PTCVJ according those which occur due to rheumatoid arthritis. PTCVJ were characterized as follows: disappearance of fat pads in the upper region (supradental PTCVJ), intensity change of the 'predental triangle' in the anterior region (predental PTCVJ), and thickening of cruciform ligaments (retrodental PTCVJ). The prevalence of PTCVJ among patients undergoing HD more than 10 years was high (26 out of 39; 66.7%). The prevalence of PTCVJ was not different between DSA and non-DSA groups. We verified that the above MRI findings might be helpful in the detection of PTCVJ. These findings were observed frequently and independently also in patients with DSA. Copyright 1999 S. Karger AG, Basel

Fabrication of complex free-standing nanostructures with concave and convex curvature via the layer-by-layer approach.

PubMed

Raoufi, Mohammad; Schönherr, Holger

2014-02-18

We report on the fabrication of unprecedented free-standing complex polymeric nanoobjects, which possess both concave and convex curvatures, by exploiting the layer-by-layer (LBL) deposition of polyelectrolytes. In a combined top-down/bottom-up replication approach pore diameter-modulated anodic aluminum oxide (AAO) templates, fabricated by temperature modulation hard anodization (TMHA), were replicated with multilayers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) to yield open nanotubes with diameters in the wide and narrow segments of 210 and 150 nm, respectively. To obtain stable pore diameter-modulated nanopores, which possess segment lengths between 1 and 5 μm and 5 and 10 μm in the narrow and wide pore portion, respectively, conventional hard anodization of aluminum was followed by a subsequent temperature-modulated anodization. After removing the backside aluminum electrode, silanizing the aluminum oxide, and passivating the exposed membrane surface with a thin layer of gold, PSS and PAH were deposited alternatingly to yield LBL multilayers. For optimized LBL multilayer thicknesses and compactness, established in separate experiments on silicon substrates and nanoporous AAO with straight pores, free-standing polymeric nanoobjects with concave and convex curvatures, were obtained. These were stable for wall thickness to pore diameter ratios of ≥0.08.

Dynamic strain-aging effect on fracture toughness of vessel steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, S.S.; Kim, I.S.

1992-03-01

In this paper the effect of dynamic strain aging (DSA) on fracture is investigated on the quenched and tempered specimens of American Society of Mechanical Engineers (ASME) standard SA508 class 3 nuclear pressure vessel steel. Serrated flow by DSA is observed between 180 and 340{degrees}C at a tensile strain rate of 2.08 {times} 10{sup {minus}4}/s and 1.25 {times} 10{sup {minus}3}/s. The DSA causes a sharp rise in the ultimate tensile strength and a marked decrease in ductility. The DSA range shifts to higher temperatures with increased strain rates. The temperature and strain rate dependence of the onset of serrations yieldsmore » an activation energy of 16.2 kcal/mol, which suggests that the process is controlled by interstitial diffusion of carbon and nitrogen in ferrite. The J{sub i} value obtained from the direct current potential drop (DCPD) method, for true crack initiation, is lowered by DSA. The drop in J{sub i} at elevated temperatures may be because of the interaction of the interstitial impurities with dislocations at the crack front.« less

Reduction of Electrolyte Components on a Coated Si Anode of Lithium-Ion Batteries.

PubMed

Gomez-Ballesteros, Jose L; Balbuena, Perla B

2017-07-20

Surface modification of Si anodes in Li-ion batteries by deposition of a thin alucone coating has demonstrated an effective way to help maintain a stable anode/electrolyte interface and good battery performance. In this work, we investigate the interactions and reactivity of the film with electrolyte components using ab initio molecular dynamics simulations. Adsorption of solvent molecules (ethylene carbonate, EC) and salt (LiPF 6 ) and reduction by two mechanisms depending on the Li content of the film (yielding open EC adsorbed on the film or C 2 H 4 + CO 3 2- ) take place near the film/electrolyte and film/anode interfaces. Reaction products incorporate into the structure of the film and create a new kind of solid-electrolyte interphase layer.

Reduction of Electrolyte Components on a Coated Si Anode of Lithium-Ion Batteries

DOE PAGES

Gomez-Ballesteros, Jose L.; Balbuena, Perla B.

2017-07-07

Surface modification of Si anodes in Li-ion batteries by deposition of a thin alucone coating has demonstrated an effective way to help maintain a stable anode/electrolyte interface and good battery performance. In this paper, we investigate the interactions and reactivity of the film with electrolyte components using ab initio molecular dynamics simulations. Adsorption of solvent molecules (ethylene carbonate, EC) and salt (LiPF 6), and reduction by two mechanisms depending on the Li content of the film (yielding open EC adsorbed on the film or C 2H 4 + CO 3 2-) take place near the film/electrolyte and film/anode interfaces. Finally,more » reactions products incorporate to the structure of the film and create a new kind of solid-electrolyte interphase layer.« less

Effective Infiltration of Gel Polymer Electrolyte into Silicon-Coated Vertically Aligned Carbon Nanofibers as Anodes for Solid-State Lithium-Ion Batteries.

PubMed

Pandey, Gaind P; Klankowski, Steven A; Li, Yonghui; Sun, Xiuzhi Susan; Wu, Judy; Rojeski, Ronald A; Li, Jun

2015-09-23

This study demonstrates the full infiltration of gel polymer electrolyte into silicon-coated vertically aligned carbon nanofibers (Si-VACNFs), a high-capacity 3D nanostructured anode, and the electrochemical characterization of its properties as an effective electrolyte/separator for future all-solid-state lithium-ion batteries. Two fabrication methods have been employed to form a stable interface between the gel polymer electrolyte and the Si-VACNF anode. In the first method, the drop-casted gel polymer electrolyte is able to fully infiltrate into the open space between the vertically aligned core-shell nanofibers and encapsulate/stabilize each individual nanofiber in the polymer matrix. The 3D nanostructured Si-VACNF anode shows a very high capacity of 3450 mAh g(-1) at C/10.5 (or 0.36 A g(-1)) rate and 1732 mAh g(-1) at 1C (or 3.8 A g(-1)) rate. In the second method, a preformed gel electrolyte film is sandwiched between an Si-VACNF electrode and a Li foil to form a half-cell. Most of the vertical core-shell nanofibers of the Si-VACNF anode are able to penetrate into the gel polymer film while retaining their structural integrity. The slightly lower capacity of 2800 mAh g(-1) at C/11 rate and ∼1070 mAh g(-1) at C/1.5 (or 2.6 A g(-1)) rate have been obtained, with almost no capacity fade for up to 100 cycles. Electrochemical impedance spectroscopy does not show noticeable changes after 110 cycles, further revealing the stable interface between the gel polymer electrolyte and the Si-VACNFs anode. These results show that the infiltrated flexible gel polymer electrolyte can effectively accommodate the stress/strain of the Si shell due to the large volume expansion/contraction during the charge-discharge processes, which is particularly useful for developing future flexible solid-state lithium-ion batteries incorporating Si-anodes.

Comparison between digital subtraction angiography and magnetic resonance angiography in investigation of nonlacunar ischemic stroke in young patients: preliminary results.

PubMed

Conforto, Adriana Bastos; Fregni, Felipe; Puglia, Paulo; Leite, Claudia da Costa; Yamamoto, Fabio Iuji; Coracini, Karen F; Scaff, Milberto

2006-06-01

We preliminarily investigated the relevance of performing digital subtraction angiography (DSA) in addition to magnetic resonance angiography (MRA) in definition of ischemic stroke etiology in young patients. DSAs and MRAs from 17 young patients with nonlacunar ischemic stroke were blindly analyzed and their impact on stroke management was evaluated. Etiologies were the same considering results of either DSA or MRA in 12/17 cases. In 15/17 patients no changes would have been made in treatment, regardless of the modality of angiography considered. These preliminary results suggest that DSA may be redundant in two thirds of ischemic strokes in young patients. Further larger prospective studies are necessary to determine indications of DSA in this age group.

[2011 Shanghai customer satisfaction report of DSA/X-ray equipment's after-service].

PubMed

Li, Bin; Qian, Jianguo; Cao, Shaoping; Zheng, Yunxin; Xu, Zitian; Wang, Lijun

2012-11-01

To improve the manufacturer's medical equipment after-sale service, the fifth Shanghai zone customer satisfaction survey was launched by the end of 2011. The DSA/X-ray equipment was setup as an independent category for the first time. From the survey we can show that the DSA/X-ray equipment's CSI is higher than last year, the customer satisfaction scores of preventive maintenance and service contract are lower than others, and CSI of local brand is lower than imported brand.

Three Dimensional Assembly in Directed Self-assembly of Block Copolymers

DOE PAGES

Segal-Peretz, Tamar; Zhou, Chun; Ren, Jiaxing; ...

2016-09-02

The three-dimensional assembly of poly (styrene-b-methyl methacrylate) (PS-b-PMMA) in chemoepitaxy and graphoepitaxy directed self-assembly (DSA) was investigated using scanning transmission electron microscopy (STEM) tomography. The tomographic characterization revealed hidden morphologies and defects at the BCP- chemical pattern interface in lamellar DSA, and probed the formation of cylinders at the bottom of cylindrical DSA for contact hole shrink. Lastly, future work will include control over 3D assembly in sub-10 nm processes.

Contrast-Enhanced and Time-of-Flight MRA at 3T Compared with DSA for the Follow-Up of Intracranial Aneurysms Treated with the WEB Device.

PubMed

Timsit, C; Soize, S; Benaissa, A; Portefaix, C; Gauvrit, J-Y; Pierot, L

2016-09-01

Imaging follow-up at 3T of intracranial aneurysms treated with the WEB Device has not been evaluated yet. Our aim was to assess the diagnostic accuracy of 3D-time-of-flight MRA and contrast-enhanced MRA at 3T against DSA, as the criterion standard, for the follow-up of aneurysms treated with the Woven EndoBridge (WEB) system. From June 2011 to December 2014, patients treated with the WEB in our institution, then followed for ≥6 months after treatment by MRA at 3T (3D-TOF-MRA and contrast-enhanced MRA) and DSA within 48 hours were included. Aneurysm occlusion was assessed with a simplified 2-grade scale (adequate occlusion [total occlusion + neck remnant] versus aneurysm remnant). Interobserver and intermodality agreement was evaluated by calculating the linear weighted κ. MRA test characteristics and predictive values were calculated from a 2 × 2 contingency table, by using DSA data as the standard of reference. Twenty-six patients with 26 WEB-treated aneurysms were included. The interobserver reproducibility was good with DSA (κ = 0.71) and contrast-enhanced-MRA (κ = 0.65) compared with moderate with 3D-TOF-MRA (κ = 0.47). Intermodality agreement with DSA was fair with both contrast-enhanced MRA (κ = 0.36) and 3D-TOF-MRA (κ = 0.36) for the evaluation of total occlusion. For aneurysm remnant detection, the prevalence was low (15%), on the basis of DSA, and both MRA techniques showed low sensitivity (25%), high specificity (100%), very good positive predictive value (100%), and very good negative predictive value (88%). Despite acceptable interobserver reproducibility and predictive values, the low sensitivity of contrast-enhanced MRA and 3D-TOF-MRA for aneurysm remnant detection suggests that MRA is a useful screening procedure for WEB-treated aneurysms, but similar to stents and flow diverters, DSA remains the criterion standard for follow-up. © 2016 by American Journal of Neuroradiology.

DSA-WDS Common Requirements: Developing a New Core Data Repository Certification

NASA Astrophysics Data System (ADS)

Minster, J. B. H.; Edmunds, R.; L'Hours, H.; Mokrane, M.; Rickards, L.

2016-12-01

The Data Seal of Approval (DSA) and the International Council for Science - World Data System (ICSU-WDS) have both developed minimally intensive core certification standards whereby digital repositories supply evidence that they are trustworthy and have a long-term outlook. Both DSA and WDS applicants have found core certification to be beneficial: building stakeholder confidence, enhancing the repository's reputation, and demonstrating that it is following good practices; as well as stimulating the repository to focus on processes and procedures, thereby achieving ever higher levels of professionalism over time.The DSA and WDS core certifications evolved independently serving initially different communities but both initiatives are multidisciplinary with catalogues of criteria and review procedures based on the same principles. Hence, to realize efficiencies, simplify assessment options, stimulate more certifications, and increase impact on the community, the Repository Audit and Certification DSA-WDS Partnership Working Group (WG) was established under the umbrella of the Research Data Alliance (RDA). The WG conducted a side-by-side analysis of both frameworks to unify the wording and criteria, ultimately leading to a harmonized Catalogue of Common Requirements for core certification of repositories—as well as a set of Common Procedures for their assessment.This presentation will focus on the collaborative effort by DSA and WDS to establish (1) a testbed comprising DSA and WDS certified data repositories to validate both the new Catalogue and Procedures, and (2) a joint Certification Board towards their practical implementation. We will describe:• The purpose and methodology of the testbed, including selection of repositories to be assessed against the common standard.• The results of the testbed, with an in-depth look at some of the comments received and issues highlighted.• General insights gained from evaluating the testbed results, the subsequent changes to the Common Requirements and Procedures, and an assessment of the success of these enhancements.• Steps by the two organizations to integrate the Common Certification into their tools and systems. In particular, the creation of Terms of Reference for the nascent DSA-WDS Certification Board.

Racial differences in the development of de-novo donor-specific antibodies and treated antibody-mediated rejection after heart transplantation.

PubMed

Cole, Robert Townsend; Gandhi, Jonathan; Bray, Robert A; Gebel, Howard M; Yin, Michael; Shekiladze, Nikolaz; Young, An; Grant, Aubrey; Mahoney, Ian; Laskar, S Raja; Gupta, Divya; Bhatt, Kunal; Book, Wendy; Smith, Andrew; Nguyen, Duc; Vega, J David; Morris, Alanna A

2018-04-01

Despite improvements in outcomes after heart transplantation, black recipients have worse survival compared with non-black recipients. The source of such disparate outcomes remains largely unknown. We hypothesize that a propensity to generate de-novo donor-specific antibodies (dnDSA) and subsequent antibody-mediated rejection (AMR) may account for racial differences in sub-optimal outcomes after heart transplant. In this study we aimed to determine the role of dnDSA and AMR in racial disparities in post-transplant outcomes. This study was a single-center, retrospective analysis of 137 heart transplant recipients (81% male, 48% black) discharged from Emory University Hospital. Patients were classified as black vs non-black for the purpose of our analysis. Kaplan-Meier and Cox regression analyses were used to evaluate the association between race and selected outcomes. The primary outcome was the development of dnDSA. Secondary outcomes included treated AMR and a composite of all-cause graft dysfunction or death. After 3.7 years of follow-up, 39 (28.5%) patients developed dnDSA and 19 (13.8%) were treated for AMR. In multivariable models, black race was associated with a higher risk of developing dnDSA (hazard ratio [HR] 3.65, 95% confidence interval [CI] 1.54 to 8.65, p = 0.003) and a higher risk of treated AMR (HR 4.86, 95% CI 1.26 to 18.72, p = 0.021) compared with non-black race. Black race was also associated with a higher risk of all-cause graft dysfunction or death in univariate analyses (HR 2.10, 95% CI 1.02 to 4.30, p = 0.044). However, in a multivariable model incorporating dnDSA, black race was no longer a significant risk factor. Only dnDSA development was significantly associated with all-cause graft dysfunction or death (HR 4.85, 95% CI 1.89 to 12.44, p = 0.001). Black transplant recipients are at higher risk for the development of dnDSA and treated AMR, which may account for racial disparities in outcomes after heart transplantation. Copyright © 2018 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Highly efficient lithium composite anode with hydrophobic molten salt in seawater

NASA Astrophysics Data System (ADS)

Zhang, Yancheng; Urquidi-Macdonald, Mirna

A lithium composite anode (lithium/1-butyl-3-methyl-imidazoleum hexafluorophosphate (BMI +PF 6-)/4-VLZ) for primary lithium/seawater semi-fuel-cells is proposed to reduce lithium-water parasitic reaction and, hence, increase the lithium anodic efficiency up to 100%. The lithium composite anode was activated when in contact with artificial seawater (3% NaCl solution) and the output was a stable anodic current density at 0.2 mA/cm 2, which lasted about 10 h under potentiostatic polarization at +0.5 V versus open circuit potential (OCP); the anodic efficiency was indirectly measured to be 100%. With time, a small traces of water diffused through the hydrophobic molten salt, BMI +PF 6-, reached the lithium interface and formed a double layer film (LiH/LiOH). Accordingly, the current density decreased and the anodic efficiency was estimated to be 90%. The hypothesis of small traces of water penetrating the molten salt and reaching the lithium anode—after several hours of operation—is supported by the collected experimental current density and hydrogen evolution, electrochemical impedance spectrum analysis, and non-mechanistic interface film modeling of lithium/BMI +PF 6-.

Dendrite Suppression by Synergistic Combination of Solid Polymer Electrolyte Crosslinked with Natural Terpenes and Lithium-Powder Anode for Lithium-Metal Batteries.

PubMed

Shim, Jimin; Lee, Jae Won; Bae, Ki Yoon; Kim, Hee Joong; Yoon, Woo Young; Lee, Jong-Chan

2017-05-22

Lithium-metal anode has fundamental problems concerning formation and growth of lithium dendrites, which prevents practical applications of next generation of high-capacity lithium-metal batteries. The synergistic combination of solid polymer electrolyte (SPE) crosslinked with naturally occurring terpenes and lithium-powder anode is promising solution to resolve the dendrite issues by substituting conventional liquid electrolyte/separator and lithium-foil anode system. A series of SPEs based on polysiloxane crosslinked with natural terpenes are prepared by facile thiol-ene click reaction under mild condition and the structural effect of terpene crosslinkers on electrochemical properties is studied. Lithium powder with large surface area is prepared by droplet emulsion technique (DET) and used as anode material. The effect of the physical state of electrolyte (solid/liquid) and morphology of lithium-metal anode (powder/foil) on dendrite growth behavior is systematically studied. The synergistic combination of SPE and lithium-powder anode suggests an effective solution to suppress the dendrite growth owing to the formation of a stable solid-electrolyte interface (SEI) layer and delocalized current density. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High performance anode based on a partially fluorinated sulfonated polyether for direct methanol fuel cells operating at 130 °C

NASA Astrophysics Data System (ADS)

Mack, Florian; Gogel, Viktor; Jörissen, Ludwig; Kerres, Jochen

2014-06-01

Due to the disadvantages of the Nafion polymer for the application in the direct methanol fuel cell (DMFC) especial at temperatures above 100 °C several polymers of the hydrocarbon type have already been investigated as membranes and ionomers in the DMFC. Among them were nonfluorinated and partially fluorinated arylene main-chain hydrocarbon polymers. In previous work, sulfonated polysulfone (sPSU) has been applied as the proton-conductive binder in the anode of a DMFC, ending up in good and stable performance. In continuation of this work, in the study presented here a polymer was prepared by polycondensation of decafluorobiphenyl and bisphenol AF. The formed polymer was sulfonated after polycondensation by oleum and the obtained partially fluorinated sulfonated polyether (SFS) was used as the binder and proton conductor in a DMFC anode operating at a temperature of 130 °C. The SFS based anode with 5% as ionomer showed comparable performance for the methanol oxidation to Nafion based anodes and significant reduced performance degradation versus Nafion and sPSU based anodes on the Nafion 115 membrane. Membrane electrode assemblies (MEAs) with the SFS based anode showed drastically improved performance compared to MEAs with Nafion based anodes during operation with lower air pressure at the cathode.

Electricity generation and brewery wastewater treatment from sequential anode-cathode microbial fuel cell.

PubMed

Wen, Qing; Wu, Ying; Zhao, Li-xin; Sun, Qian; Kong, Fan-ying

2010-02-01

A sequential anode-cathode double-chamber microbial fuel cell (MFC), in which the effluent of anode chamber was used as a continuous feed for an aerated cathode chamber, was constructed in this experiment to investigate the performance of brewery wastewater treatment in conjugation with electricity generation. Carbon fiber was used as anode and plain carbon felt with biofilm as cathode. When hydraulic retention time (HRT) was 14.7 h, a relatively high chemical oxygen demand (COD) removal efficiency of 91.7%-95.7% was achieved under long-term stable operation. The MFC displayed an open circuit voltage of 0.434 V and a maximum power density of 830 mW/m(3) at an external resistance of 300 Omega. To estimate the electrochemical performance of the MFC, electrochemical measurements were carried out and showed that polarization resistance of anode was the major limiting factor in the MFC. Since a high COD removal efficiency was achieved, we conclude that the sequential anode-cathode MFC constructed with bio-cathode in this experiment could provide a new approach for brewery wastewater treatment.

Electrochemistry and safety of Li 4Ti 5O 12 and graphite anodes paired with LiMn 2O 4 for hybrid electric vehicle Li-ion battery applications

NASA Astrophysics Data System (ADS)

Belharouak, Ilias; Koenig, Gary M.; Amine, K.

A promising anode material for hybrid electric vehicles (HEVs) is Li 4Ti 5O 12 (LTO). LTO intercalates lithium at a voltage of ∼1.5 V relative to lithium metal, and thus this material has a lower energy compared to a graphite anode for a given cathode material. However, LTO has promising safety and cycle life characteristics relative to graphite anodes. Herein, we describe electrochemical and safety characterizations of LTO and graphite anodes paired with LiMn 2O 4 cathodes in pouch cells. The LTO anode outperformed graphite with regards to capacity retention on extended cycling, pulsing impedance, and calendar life and was found to be more stable to thermal abuse from analysis of gases generated at elevated temperatures and calorimetric data. The safety, calendar life, and pulsing performance of LTO make it an attractive alternative to graphite for high power automotive applications, in particular when paired with LiMn 2O 4 cathode materials.

Electricity generation and brewery wastewater treatment from sequential anode-cathode microbial fuel cell*

PubMed Central

Wen, Qing; Wu, Ying; Zhao, Li-xin; Sun, Qian; Kong, Fan-ying

2010-01-01

A sequential anode-cathode double-chamber microbial fuel cell (MFC), in which the effluent of anode chamber was used as a continuous feed for an aerated cathode chamber, was constructed in this experiment to investigate the performance of brewery wastewater treatment in conjugation with electricity generation. Carbon fiber was used as anode and plain carbon felt with biofilm as cathode. When hydraulic retention time (HRT) was 14.7 h, a relatively high chemical oxygen demand (COD) removal efficiency of 91.7%–95.7% was achieved under long-term stable operation. The MFC displayed an open circuit voltage of 0.434 V and a maximum power density of 830 mW/m3 at an external resistance of 300 Ω. To estimate the electrochemical performance of the MFC, electrochemical measurements were carried out and showed that polarization resistance of anode was the major limiting factor in the MFC. Since a high COD removal efficiency was achieved, we conclude that the sequential anode-cathode MFC constructed with bio-cathode in this experiment could provide a new approach for brewery wastewater treatment. PMID:20104642

Suppression of Dendritic Lithium Growth by in Situ Formation of a Chemically Stable and Mechanically Strong Solid Electrolyte Interphase.

PubMed

Wan, Guojia; Guo, Feihu; Li, Hui; Cao, Yuliang; Ai, Xinping; Qian, Jiangfeng; Li, Yangxing; Yang, Hanxi

2018-01-10

The growth and proliferation of Li dendrites during repeated Li cycling has long been a crucial issue that hinders the development of secondary Li-metal batteries. Building a stable and robust solid state electrolyte interphase (SEI) on the Li-anode surface is regarded as a promising strategy to overcome the dendrite issues. In this work, we report a simple strategy to engineer the interface chemistry of Li-metal anodes by using tiny amounts of dimethyl sulfate (DMS, C 2 H 6 SO 4 ) as the SEI-forming additive. With the preferential reduction of DMS, an SEI layer composed of Li 2 S/Li 2 O forms on the Li surface. This inorganic SEI layer features high structural modulus and low interfacial resistant, enabling a dense and dendrite-free Li deposition as evidenced by scanning electron microscopy, atomic force microscopy, and in situ optical images. In addition, this SEI layer can prevent the deposited Li from direct contact with corrosive electrolytes, thus rendering an improved cycling stability of Li anodes with an average Coulombic efficiency of 97% for up to 150 cycles. When the DMS additive is introduced into a Li/NCM full cell, the cycle life of Li-metal batteries can be also improved significantly. This work demonstrates a feasible route to suppress Li dendrite growth by designing appropriate film-forming additives to regulate the interfacial properties of the SEI layer, and also the sulfonyl-based derivatives revealed in this work represent a large variety of new film-forming molecules, providing a broad selectivity for constructing high efficiency and cycle-stable Li anodes to address the intrinsic problems of rechargeable Li-metal batteries.

Surface Fluorination of Reactive Battery Anode Materials for Enhanced Stability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Jie; Liao, Lei; Shi, Feifei

Significant increases in the energy density of batteries must be achieved by exploring new materials and cell configurations. Lithium metal and lithiated silicon are two promising high-capacity anode materials. Unfortunately, both of these anodes require a reliable passivating layer to survive the serious environmental corrosion during handling and cycling. Here we developed a surface fluorination process to form a homogeneous and dense LiF coating on reactive anode materials, with in situ generated fluorine gas, by using a fluoropolymer, CYTOP, as the precursor. The process is effectively a “reaction in the beaker”, avoiding direct handling of highly toxic fluorine gas. Formore » lithium metal, this LiF coating serves as a chemically stable and mechanically strong interphase, which minimizes the corrosion reaction with carbonate electrolytes and suppresses dendrite formation, enabling dendrite-free and stable cycling over 300 cycles with current densities up to 5 mA/cm 2. Lithiated silicon can serve as either a pre-lithiation additive for existing lithium-ion batteries or a replacement for lithium metal in Li–O 2 and Li–S batteries. However, lithiated silicon reacts vigorously with the standard slurry solvent N-methyl-2-pyrrolidinone (NMP), indicating it is not compatible with the real battery fabrication process. With the protection of crystalline and dense LiF coating, Li xSi can be processed in anhydrous NMP with a high capacity of 2504 mAh/g. With low solubility of LiF in water, this protection layer also allows Li xSi to be stable in humid air (~40% relative humidity). Furthermore, this facile surface fluorination process brings huge benefit to both the existing lithium-ion batteries and next-generation lithium metal batteries.« less

Surface Fluorination of Reactive Battery Anode Materials for Enhanced Stability

DOE PAGES

Zhao, Jie; Liao, Lei; Shi, Feifei; ...

2017-07-26

Significant increases in the energy density of batteries must be achieved by exploring new materials and cell configurations. Lithium metal and lithiated silicon are two promising high-capacity anode materials. Unfortunately, both of these anodes require a reliable passivating layer to survive the serious environmental corrosion during handling and cycling. Here we developed a surface fluorination process to form a homogeneous and dense LiF coating on reactive anode materials, with in situ generated fluorine gas, by using a fluoropolymer, CYTOP, as the precursor. The process is effectively a “reaction in the beaker”, avoiding direct handling of highly toxic fluorine gas. Formore » lithium metal, this LiF coating serves as a chemically stable and mechanically strong interphase, which minimizes the corrosion reaction with carbonate electrolytes and suppresses dendrite formation, enabling dendrite-free and stable cycling over 300 cycles with current densities up to 5 mA/cm 2. Lithiated silicon can serve as either a pre-lithiation additive for existing lithium-ion batteries or a replacement for lithium metal in Li–O 2 and Li–S batteries. However, lithiated silicon reacts vigorously with the standard slurry solvent N-methyl-2-pyrrolidinone (NMP), indicating it is not compatible with the real battery fabrication process. With the protection of crystalline and dense LiF coating, Li xSi can be processed in anhydrous NMP with a high capacity of 2504 mAh/g. With low solubility of LiF in water, this protection layer also allows Li xSi to be stable in humid air (~40% relative humidity). Furthermore, this facile surface fluorination process brings huge benefit to both the existing lithium-ion batteries and next-generation lithium metal batteries.« less

7 CFR 766.51 - General.

Code of Federal Regulations, 2012 CFR

2012-01-01

... PROGRAMS DIRECT LOAN SERVICING-SPECIAL Disaster Set-Aside § 766.51 General. (a) DSA is available to borrowers with program loans who suffered losses as a result of a natural disaster. (b) DSA is not intended...

7 CFR 766.51 - General.

Code of Federal Regulations, 2013 CFR

2013-01-01

... PROGRAMS DIRECT LOAN SERVICING-SPECIAL Disaster Set-Aside § 766.51 General. (a) DSA is available to borrowers with program loans who suffered losses as a result of a natural disaster. (b) DSA is not intended...

7 CFR 766.51 - General.

Code of Federal Regulations, 2011 CFR

2011-01-01

... PROGRAMS DIRECT LOAN SERVICING-SPECIAL Disaster Set-Aside § 766.51 General. (a) DSA is available to borrowers with program loans who suffered losses as a result of a natural disaster. (b) DSA is not intended...

7 CFR 766.51 - General.

Code of Federal Regulations, 2014 CFR

2014-01-01

... PROGRAMS DIRECT LOAN SERVICING-SPECIAL Disaster Set-Aside § 766.51 General. (a) DSA is available to borrowers with program loans who suffered losses as a result of a natural disaster. (b) DSA is not intended...

7 CFR 766.51 - General.

Code of Federal Regulations, 2010 CFR

2010-01-01

... PROGRAMS DIRECT LOAN SERVICING-SPECIAL Disaster Set-Aside § 766.51 General. (a) DSA is available to borrowers with program loans who suffered losses as a result of a natural disaster. (b) DSA is not intended...

Model-based guiding pattern synthesis for robust assembly of contact layers using directed self-assembly

NASA Astrophysics Data System (ADS)

Mitra, Joydeep; Torres, Andres; Ma, Yuansheng; Pan, David Z.

2018-01-01

Directed self-assembly (DSA) has emerged as one of the most compelling next-generation patterning techniques for sub 7 nm via or contact layers. A key issue in enabling DSA as a mainstream patterning technique is the generation of grapho-epitaxy-based guiding pattern (GP) shapes to assemble the contact patterns on target with high fidelity and resolution. Current GP generation is mostly empirical, and limited to a very small number of via configurations. We propose the first model-based GP synthesis algorithm and methodology for on-target and robust DSA, on general via pattern configurations. The final postoptical proximity correction-printed GPs derived from our original synthesized GPs are resilient to process variations and continue to maintain the same DSA fidelity in terms of placement error and target shape.

Myocardial ischemia during intravenous DSA in patients with cardiac disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hesselink, J.R.; Hayman, L.A.; Chung, K.J.

1984-12-01

A prospective study was performed for 48 patients who had histories of angina and were referred for digital subtraction angiography (DSA). Cardiac disease was graded according to the American Heart Association (AHA) functional classification system. Each patient received 2-5 injections of 40-ml diatrizoate meglumine and diatrizoate sodium at 15 ml per second in the superior vena cava. Of the 28 patients in functional Classes I or II, 11% had angina and 32% had definite ischemic ECG changes after the DSA injections. Of the patients in functional Class III 63% had angina, and 58% had definite ischemic ECG changes after themore » injections. These observed cardiac effects following bolus injections of hypertonic ionic contrast media indicate that special precautions are necessary when performing intravenous DSA examinations on this group of high risk patients.« less

Antibodies against toluene diisocyanate protein conjugates. Three methods of measurement.

PubMed

Patterson, R; Harris, K E; Zeiss, C R

1983-12-01

With the use of canine antisera against toluene diisocyanate (TDI)-dog serum albumin (DSA), techniques for measuring antibody against TDI-DSA were evaluated. The use of an ammonium sulfate precipitation assay showed suggestive evidence of antibody binding but high levels of TDI-DSA precipitation in the absence of antibody limit any usefulness of this technique. Double-antibody co-precipitation techniques will measure total antibody or Ig class antibody against 125I-TDI-DSA. These techniques are quantitative. The polystyrene tube radioimmunoassay is a highly sensitive method of detecting and quantitatively estimating IgG antibody. The enzyme linked immunosorbent assay is a rapidly adaptable method for the quantitative estimation of IgG, IgA, and IgM against TDI-homologous proteins. All these techniques were compared and results are demonstrated by using the same serum sample for analysis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wehrschuetz, M., E-mail: martin.wehrschuetz@klinikum-graz.at; Aschauer, M.; Portugaller, H.

The purpose of this study was to assess interobserver variability and accuracy in the evaluation of renal artery stenosis (RAS) with gadolinium-enhanced MR angiography (MRA) and digital subtraction angiography (DSA) in patients with hypertension. The authors found that source images are more accurate than maximum intensity projection (MIP) for depicting renal artery stenosis. Two independent radiologists reviewed MRA and DSA from 38 patients with hypertension. Studies were postprocessed to display images in MIP and source images. DSA was the standard for comparison in each patient. For each main renal artery, percentage stenosis was estimated for any stenosis detected by themore » two radiologists. To calculate sensitivity, specificity and accuracy, MRA studies and stenoses were categorized as normal, mild (1-39%), moderate (40-69%) or severe ({>=}70%), or occluded. DSA stenosis estimates of 70% or greater were considered hemodynamically significant. Analysis of variance demonstrated that MIP estimates of stenosis were greater than source image estimates for both readers. Differences in estimates for MIP versus DSA reached significance in one reader. The interobserver variance for MIP, source images and DSA was excellent (0.80< {kappa}{<=} 0.90). The specificity of source images was high (97%) but less for MIP (87%); average accuracy was 92% for MIP and 98% for source images. In this study, source images are significantly more accurate than MIP images in one reader with a similar trend was observed in the second reader. The interobserver variability was excellent. When renal artery stenosis is a consideration, high accuracy can only be obtained when source images are examined.« less

Routine Use of Three-Dimensional Contrast-Enhanced Moving-Table MR Angiography in Patients with Peripheral Arterial Occlusive Disease: Comparison with Selective Digital Subtraction Angiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deutschmann, Hannes A.; Schoellnast, Helmut; Portugaller, Horst R.

2006-10-15

Purpose. To compare the diagnostic accuracy of contrast-enhanced (CE) three-dimensional (3D) moving-table magnetic resonance (MR) angiography with that of selective digital subtraction angiography (DSA) for routine clinical investigation in patients with peripheral arterial occlusive disease. Methods. Thirty-eight patients underwent CE 3D moving-table MR angiography of the pelvic and peripheral arteries. A commercially available large-field-of-view adapter and a dedicated peripheral vascular phased-array coil were used. MR angiograms were evaluated for grade of arterial stenosis, diagnostic quality, and presence of artifacts. MR imaging results for each patient were compared with those of selective DSA. Results. Two hundred and twenty-six arterial segments inmore » 38 patients were evaluated by both selective DSA and MR angiography. No complications related to MR angiography were observed. There was agreement in stenosis classification in 204 (90.3%) segments; MR angiography overgraded 16 (7%) segments and undergraded 6 (2.7%) segments. Compared with selective DSA, MR angiography provided high sensitivity and specificity and excellent interobserver agreement for detection of severe stenosis (97% and 95%, {kappa} = 0.9 {+-} 0.03) and moderate stenosis (96.5% and 94.3%, {kappa} = 0.9 {+-} 0.03). Conclusion. Compared with selective DSA, moving-table MR angiography proved to be an accurate, noninvasive method for evaluation of peripheral arterial occlusive disease and may thus serve as an alternative to DSA in clinical routine.« less

Chemical compatibility and properties of suspension plasma-sprayed SrTiO3-based anodes for intermediate-temperature solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Zhang, Shan-Lin; Li, Cheng-Xin; Li, Chang-Jiu

2014-10-01

La-doped strontium titanate (LST) is a promising, redox-stable perovskite material for direct hydrocarbon oxidation anodes in intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this study, nano-sized LST and Sm-doped ceria (SDC) powders are produced by the sol-gel and glycine-nitrate processes, respectively. The chemical compatibility between LST and electrolyte materials is studied. A LST-SDC composite anode is prepared by suspension plasma spraying (SPS). The effects of annealing conditions on the phase structure, microstructure, and chemical stability of the LST-SDC composite anode are investigated. The results indicate that the suspension plasma-sprayed LST-SDC anode has the same phase structure as the original powders. LST exhibits a good chemical compatibility with SDC and Mg/Sr-doped lanthanum gallate (LSGM). The anode has a porosity of ∼40% with a finely porous structure that provides high gas permeability and a long three-phase boundary for the anode reaction. Single cells assembled with the LST-SDC anode, La0.8Sr0.2Ga0.8Mg0.2O3 electrolyte, and La0.8Sr0.2CoO3-SDC cathode show a good performance at 650-800 °C. The annealing reduces the impedances due to the enhancement in the bonding between the particles in the anode and interface of anode and LSGM electrolyte, thus improving the output performance of the cell.

High capacity and stable all-solid-state Li ion battery using SnO2-embedded nanoporous carbon.

PubMed

Notohara, Hiroo; Urita, Koki; Yamamura, Hideyuki; Moriguchi, Isamu

2018-06-08

Extensive research efforts are devoted to development of high performance all-solid-state lithium ion batteries owing to their potential in not only improving safety but also achieving high stability and high capacity. However, conventional approaches based on a fabrication of highly dense electrode and solid electrolyte layers and their close contact interface is not always applicable to high capacity alloy- and/or conversion-based active materials such as SnO 2 accompanied with large volume change in charging-discharging. The present work demonstrates that SnO 2 -embedded nanoporous carbons without solid electrolyte inside the nanopores are a promising candidate for high capacity and stable anode material of all-solid-state battery, in which the volume change reactions are restricted in the nanopores to keep the constant electrode volume. A prototype all-solid-state full cell consisting of the SnO 2 -based anode and a LiNi 1/3 Co 1 / 3 Mn 1/3 O 2 -based cathode shows a good performance of 2040 Wh/kg at 268.6 W/kg based on the anode material weight.

V2O5-C-SnO2 Hybrid Nanobelts as High Performance Anodes for Lithium-ion Batteries

PubMed Central

Zhang, Linfei; Yang, Mingyang; Zhang, Shengliang; Wu, Zefei; Amini, Abbas; Zhang, Yi; Wang, Dongyong; Bao, Shuhan; Lu, Zhouguang; Wang, Ning; Cheng, Chun

2016-01-01

The superior performance of metal oxide nanocomposites has introduced them as excellent candidates for emerging energy sources, and attracted significant attention in recent years. The drawback of these materials is their inherent structural pulverization which adversely impacts their performance and makes the rational design of stable nanocomposites a great challenge. In this work, functional V2O5-C-SnO2 hybrid nanobelts (VCSNs) with a stable structure are introduced where the ultradispersed SnO2 nanocrystals are tightly linked with glucose on the V2O5 surface. The nanostructured V2O5 acts as a supporting matrix as well as an active electrode component. Compared with existing carbon-V2O5 hybrid nanobelts, these hybrid nanobelts exhibit a much higher reversible capacity and architectural stability when used as anode materials for lithium-ion batteries. The superior cyclic performance of VCSNs can be attributed to the synergistic effects of SnO2 and V2O5. However, limited data are available for V2O5-based anodes in lithium-ion battery design. PMID:27677326

Organosulfide-plasticized solid-electrolyte interphase layer enables stable lithium metal anodes for long-cycle lithium-sulfur batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Guoxing; Gao, Yue; He, Xin

Lithium metal is a promising anode candidate for the next-generation rechargeable battery due to its highest specific capacity (3860 mA h g -1) and lowest potential, but low Coulombic efficiency and formation of lithium dendrites hinder its practical application. Here, we report a self-formed flexible hybrid solid-electrolyte interphase layer through co-deposition of organosulfides/organopolysulfides and inorganic lithium salts using sulfur-containing polymers as an additive in the electrolyte. The organosulfides/organopolysulfides serve as “plasticizer” in the solid-electrolyte interphase layer to improve its mechanical flexibility and toughness. The as-formed robust solid-electrolyte interphase layers enable dendrite-free lithium deposition and significantly improve Coulombic efficiency (99% overmore » 400 cycles at a current density of 2mAcm -2). A lithium-sulfur battery based on this strategy exhibits long cycling life (1000 cycles) and good capacity retention. This study reveals an avenue to effectively fabricate stable solid-electrolyte interphase layer for solving the issues associated with lithium metal anodes.« less

V2O5-C-SnO2 Hybrid Nanobelts as High Performance Anodes for Lithium-ion Batteries

NASA Astrophysics Data System (ADS)

Zhang, Linfei; Yang, Mingyang; Zhang, Shengliang; Wu, Zefei; Amini, Abbas; Zhang, Yi; Wang, Dongyong; Bao, Shuhan; Lu, Zhouguang; Wang, Ning; Cheng, Chun

2016-09-01

The superior performance of metal oxide nanocomposites has introduced them as excellent candidates for emerging energy sources, and attracted significant attention in recent years. The drawback of these materials is their inherent structural pulverization which adversely impacts their performance and makes the rational design of stable nanocomposites a great challenge. In this work, functional V2O5-C-SnO2 hybrid nanobelts (VCSNs) with a stable structure are introduced where the ultradispersed SnO2 nanocrystals are tightly linked with glucose on the V2O5 surface. The nanostructured V2O5 acts as a supporting matrix as well as an active electrode component. Compared with existing carbon-V2O5 hybrid nanobelts, these hybrid nanobelts exhibit a much higher reversible capacity and architectural stability when used as anode materials for lithium-ion batteries. The superior cyclic performance of VCSNs can be attributed to the synergistic effects of SnO2 and V2O5. However, limited data are available for V2O5-based anodes in lithium-ion battery design.

Organosulfide-plasticized solid-electrolyte interphase layer enables stable lithium metal anodes for long-cycle lithium-sulfur batteries

DOE PAGES

Li, Guoxing; Gao, Yue; He, Xin; ...

2017-10-11

Lithium metal is a promising anode candidate for the next-generation rechargeable battery due to its highest specific capacity (3860 mA h g -1) and lowest potential, but low Coulombic efficiency and formation of lithium dendrites hinder its practical application. Here, we report a self-formed flexible hybrid solid-electrolyte interphase layer through co-deposition of organosulfides/organopolysulfides and inorganic lithium salts using sulfur-containing polymers as an additive in the electrolyte. The organosulfides/organopolysulfides serve as “plasticizer” in the solid-electrolyte interphase layer to improve its mechanical flexibility and toughness. The as-formed robust solid-electrolyte interphase layers enable dendrite-free lithium deposition and significantly improve Coulombic efficiency (99% overmore » 400 cycles at a current density of 2mAcm -2). A lithium-sulfur battery based on this strategy exhibits long cycling life (1000 cycles) and good capacity retention. This study reveals an avenue to effectively fabricate stable solid-electrolyte interphase layer for solving the issues associated with lithium metal anodes.« less

Advanced Sodium Ion Battery Anode Constructed via Chemical Bonding between Phosphorus, Carbon Nanotube, and Cross-Linked Polymer Binder.

PubMed

Song, Jiangxuan; Yu, Zhaoxin; Gordin, Mikhail L; Li, Xiaolin; Peng, Huisheng; Wang, Donghai

2015-12-22

Maintaining structural stability is a great challenge for high-capacity conversion electrodes with large volume change but is necessary for the development of high-energy-density, long-cycling batteries. Here, we report a stable phosphorus anode for sodium ion batteries by the synergistic use of chemically bonded phosphorus-carbon nanotube (P-CNT) hybrid and cross-linked polymer binder. The P-CNT hybrid was synthesized through ball-milling of red phosphorus and carboxylic group functionalized carbon nanotubes. The P-O-C bonds formed in this process help maintain contact between phosphorus and CNTs, leading to a durable hybrid. In addition, cross-linked carboxymethyl cellulose-citric acid binder was used to form a robust electrode. As a result, this anode delivers a stable cycling capacity of 1586.2 mAh/g after 100 cycles, along with high initial Coulombic efficiency of 84.7% and subsequent cycling efficiency of ∼99%. The unique electrode framework through chemical bonding strategy reported here is potentially inspirable for other electrode materials with large volume change in use.

SiLix-C Nanocomposites

NASA Technical Reports Server (NTRS)

Henry, Francois

2015-01-01

For this Phase II project, Superior Graphite Co., in collaboration with the Georgia Institute of Technology and Streamline Nanotechnologies, Inc., developed, explored the properties of, and demonstrated the enhanced capabilities of novel nanostructured SiLix-C anodes. These anodes can retain high capacity at a rapid 2-hour discharge rate and at 0 C when used in Li-ion batteries. In Phase I, these advanced anode materials had specific capacity in excess of 1,000 mAh/g, minimal irreversible capacity losses, and stable performance for 20 cycles at C/1. The goals in Phase II were to develop and apply a variety of novel nanomaterials, fine-tune the properties of composite particles at the nanoscale, optimize the composition of the anodes, and select appropriate binder and electrolytes. In order to achieve a breakthrough in power characteristics of Li-ion batteries, the team developed new nanostructured SiLix-C anode materials to offer up to 1,200 mAh/g at C/2 at 0 C.

Robotic digital subtraction angiography systems within the hybrid operating room.

PubMed

Murayama, Yuichi; Irie, Koreaki; Saguchi, Takayuki; Ishibashi, Toshihiro; Ebara, Masaki; Nagashima, Hiroyasu; Isoshima, Akira; Arakawa, Hideki; Takao, Hiroyuki; Ohashi, Hiroki; Joki, Tatsuhiro; Kato, Masataka; Tani, Satoshi; Ikeuchi, Satoshi; Abe, Toshiaki

2011-05-01

Fully equipped high-end digital subtraction angiography (DSA) within the operating room (OR) environment has emerged as a new trend in the fields of neurosurgery and vascular surgery. To describe initial clinical experience with a robotic DSA system in the hybrid OR. A newly designed robotic DSA system (Artis zeego; Siemens AG, Forchheim, Germany) was installed in the hybrid OR. The system consists of a multiaxis robotic C arm and surgical OR table. In addition to conventional neuroendovascular procedures, the system was used as an intraoperative imaging tool for various neurosurgical procedures such as aneurysm clipping and spine instrumentation. Five hundred one neurosurgical procedures were successfully conducted in the hybrid OR with the robotic DSA. During surgical procedures such as aneurysm clipping and arteriovenous fistula treatment, intraoperative 2-/3-dimensional angiography and C-arm-based computed tomographic images (DynaCT) were easily performed without moving the OR table. Newly developed virtual navigation software (syngo iGuide; Siemens AG) can be used in frameless navigation and in access to deep-seated intracranial lesions or needle placement. This newly developed robotic DSA system provides safe and precise treatment in the fields of endovascular treatment and neurosurgery.

Alloantibody and Autoantibody Monitoring Predicts Islet Transplantation Outcome in Human Type 1 Diabetes

PubMed Central

Piemonti, Lorenzo; Everly, Matthew J.; Maffi, Paola; Scavini, Marina; Poli, Francesca; Nano, Rita; Cardillo, Massimo; Melzi, Raffaella; Mercalli, Alessia; Sordi, Valeria; Lampasona, Vito; Espadas de Arias, Alejandro; Scalamogna, Mario; Bosi, Emanuele; Bonifacio, Ezio; Secchi, Antonio; Terasaki, Paul I.

2013-01-01

Long-term clinical outcome of islet transplantation is hampered by the rejection and recurrence of autoimmunity. Accurate monitoring may allow for early detection and treatment of these potentially compromising immune events. Islet transplant outcome was analyzed in 59 consecutive pancreatic islet recipients in whom baseline and de novo posttransplant autoantibodies (GAD antibody, insulinoma-associated protein 2 antigen, zinc transporter type 8 antigen) and donor-specific alloantibodies (DSA) were quantified. Thirty-nine recipients (66%) showed DSA or autoantibody increases (de novo expression or titer increase) after islet transplantation. Recipients who had a posttransplant antibody increase showed similar initial performance but significantly lower graft survival than patients without an increase (islet autoantibodies P < 0.001, DSA P < 0.001). Posttransplant DSA or autoantibody increases were associated with HLA-DR mismatches (P = 0.008), induction with antithymocyte globulin (P = 0.0001), and pretransplant panel reactive alloantibody >15% in either class I or class II (P = 0.024) as independent risk factors and with rapamycin as protective (P = 0.006) against antibody increases. DSA or autoantibody increases after islet transplantation are important prognostic markers, and their identification could potentially lead to improved islet cell transplant outcomes. PMID:23274902

A general design strategy for block copolymer directed self-assembly patterning of integrated circuits contact holes using an alphabet approach.

PubMed

Yi, He; Bao, Xin-Yu; Tiberio, Richard; Wong, H-S Philip

2015-02-11

Directed self-assembly (DSA) is a promising lithography candidate for technology nodes beyond 14 nm. Researchers have shown contact hole patterning for random logic circuits using DSA with small physical templates. This paper introduces an alphabet approach that uses a minimal set of small physical templates to pattern all contacts configurations on integrated circuits. We illustrate, through experiments, a general and scalable template design strategy that links the DSA material properties to the technology node requirements.

Diagnostic accuracy of 64-slice multidetector CT angiography for detection of in-stent restenosis of vertebral artery ostium stents: comparison with conventional angiography.

PubMed

Lee, Youn Joo; Lim, Yeon Soo; Lim, Hyun Wook; Yoo, Won Jong; Choi, Byung Gil; Kim, Bum Soo

2014-10-01

There are very few reports assessing in-stent restenosis (ISR) after vertebral artery ostium (VAO) stents using multidetector computed tomography (MDCT). To compare the diagnostic accuracy of computed tomography angiography (CTA) using 64-slice MDCT with digital subtraction angiography (DSA) for detection of significant ISR after VAO stenting. The study evaluated 57 VAO stents in 57 patients (39 men, 18 women; mean age 64 years [range, 48-90 years]). All stents were scanned with a 64-slice MDCT scanner. Three sets of images were reconstructed with three different convolution kernels. Two observers who were blinded to the results of DSA assessed the diagnostic accuracy of CTA for detecting significant ISR (≥50% diameter narrowing) of VAO stents in comparison with DSA as the reference standard. The sensitivity, specificity, positive and negative predictive values, and accuracy were calculated. Of the 57 stents, 46 (81%) were assessable using CTA, while 11 (19%) were not. No stents with diameters ≤2.75 mm were assessable. DSA revealed 13 cases of significant ISR in all stents. The respective sensitivity, specificity, positive and negative predictive values, and accuracy were 92%, 82%, 60%, 97%, and 84% for all stents. On excluding the 11 non-assessable stents, the respective values were 88%, 95%, 78%, 97%, and 93%. Of the 46 CTA assessable stents, eight significant ISRs were diagnosed on DSA. Seven of eight patients with significant ISR by DSA were diagnosed correctly with CTA. The area under the receiver-operating characteristic curve (AUC) was 0.87 for all stents and 0.91 for assessable stents, indicating good to excellent agreement between CTA and DSA for detecting significant ISR after VAO stenting. Sixty-four-slice MDCT is a promising non-invasive method of assessing stent patency and can exclude significant ISR with high diagnostic values after VAO stenting. © The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Blunt cerebrovascular injury screening with 64-channel multidetector computed tomography: more slices finally cut it.

PubMed

Paulus, Elena M; Fabian, Timothy C; Savage, Stephanie A; Zarzaur, Ben L; Botta, Vandana; Dutton, Wesley; Croce, Martin A

2014-02-01

Aggressive screening to diagnose blunt cerebrovascular injury (BCVI) results in early treatment, leading to improved outcomes and reduced stroke rates. While computed tomographic angiography (CTA) has been widely adopted for BCVI screening, evidence of its diagnostic sensitivity is marginal. Previous work from our institution using 32-channel multidetector CTA in 684 patients demonstrated an inadequate sensitivity of 51% (Ann Surg. 2011,253: 444-450). Digital subtraction angiography (DSA) continues to be the reference standard of diagnosis but has significant drawbacks of invasiveness and resource demands. There have been continued advances in CT technology, and this is the first report of an extensive experience with 64-channel multidetector CTA. Patients screened for BCVI using CTA and DSA (reference) at a Level 1 trauma center during the 12-month period ending in May 2012 were identified. Results of CTA and DSA, complications, and strokes were retrospectively reviewed and compared. A total of 594 patients met criteria for BCVI screening and underwent both CTA and DSA. One hundred twenty-eight patients (22% of those screened) had 163 injured vessels: 99 (61%) carotid artery injuries and 64 (39%) vertebral artery injuries. Sixty-four-channel CTA demonstrated an overall sensitivity per vessel of 68% and specificity of 92%. The 52 false-negative findings on CTA were composed of 34 carotid artery injuries and 18 vertebral artery injuries; 32 (62%) were Grade I injuries. Overall, positive predictive value was 36.2%, and negative predictive value was 97.5%. Six procedure-related complications (1%) occurred with DSA, including two iatrogenic dissections and one stroke. Sixty-four-channel CTA demonstrated a significantly improved sensitivity of 68% versus the 51% previously reported for the 32-channel CTA (p = 0.0075). Sixty-two percent of the false-negative findings occurred with low-grade injuries. Considering complications, cost, and resource demand associated with DSA, this study suggests that 64-channel CTA may replace DSA as the primary screening tool for BCVI. Diagnostic study, level III.

Potential of dynamic spectrum allocation in LTE macro networks

NASA Astrophysics Data System (ADS)

Hoffmann, H.; Ramachandra, P.; Kovács, I. Z.; Jorguseski, L.; Gunnarsson, F.; Kürner, T.

2015-11-01

In recent years Mobile Network Operators (MNOs) worldwide are extensively deploying LTE networks in different spectrum bands and utilising different bandwidth configurations. Initially, the deployment is coverage oriented with macro cells using the lower LTE spectrum bands. As the offered traffic (i.e. the requested traffic from the users) increases the LTE deployment evolves with macro cells expanded with additional capacity boosting LTE carriers in higher frequency bands complemented with micro or small cells in traffic hotspot areas. For MNOs it is crucial to use the LTE spectrum assets, as well as the installed network infrastructure, in the most cost efficient way. The dynamic spectrum allocation (DSA) aims at (de)activating the available LTE frequency carriers according to the temporal and spatial traffic variations in order to increase the overall LTE system performance in terms of total network capacity by reducing the interference. This paper evaluates the DSA potential of achieving the envisaged performance improvement and identifying in which system and traffic conditions the DSA should be deployed. A self-optimised network (SON) DSA algorithm is also proposed and evaluated. The evaluations have been carried out in a hexagonal and a realistic site-specific urban macro layout assuming a central traffic hotspot area surrounded with an area of lower traffic with a total size of approximately 8 × 8 km2. The results show that up to 47 % and up to 40 % possible DSA gains are achievable with regards to the carried system load (i.e. used resources) for homogenous traffic distribution with hexagonal layout and for realistic site-specific urban macro layout, respectively. The SON DSA algorithm evaluation in a realistic site-specific urban macro cell deployment scenario including realistic non-uniform spatial traffic distribution shows insignificant cell throughput (i.e. served traffic) performance gains. Nevertheless, in the SON DSA investigations, a gain of up to 25 % has been observed when analysing the resource utilisation in the non-hotspot cells.

Correlation Between Contrast Time-Density Time on Digital Subtraction Angiography and Flow: An in Vitro Study.

PubMed

Brunozzi, Denise; Shakur, Sophia F; Ismail, Rahim; Linninger, Andreas; Hsu, Chih-Yang; Charbel, Fady T; Alaraj, Ali

2018-02-01

Digital subtraction angiography (DSA) provides an excellent anatomic characterization of cerebral vasculature, but hemodynamic assessment is often qualitative and subjective. Various clinical algorithms have been produced to semiquantify flow from the data obtained from DSA, but few have tested them against reliable flow values. An arched flow model was created and injected with contrast material. Seventeen injections were acquired in anterior-posterior and lateral DSA projections, and 4 injections were acquired in oblique projection. Image intensity change over the angiogram cycle of each DSA run was analyzed through a custom MATLAB code. Time-density plots obtained were divided into 3 components (time-density times, TDTs): TDT 10%-100% (time needed for contrast material to change image intensity from 10% to 100%), TDT 100%-10% (time needed for contrast material to change image intensity from 100% to 10%), and TDT 25%-25% (time needed for contrast material to change from 25% image intensity to 25%). Time-density index (TDI) was defined as model cross-sectional area to TDT ratio, and it was measured against different flow rates. TDI 10%-100% , TDI 100%-10% , and TDI 25%-25% all correlated significantly with flow (P < 0.001). TDI 10%-100% , TDI 100%-10% , and TDI 25%-25% showed, respectively, a correlation coefficient of 0.91, 0.91, and 0.97 in the anterior-posterior DSA projections (P < 0.001). In the lateral DSA projection, TDI 100%-10% showed a weaker correlation (r = 0.57; P = 0.03). Also in the oblique DSA projection, TDIs correlated significantly with flow. TDI on DSA correlates significantly with flow. Although in vitro studies might overlook conditions that occur in patients, this method appears to correlate with the flow and could offer a semiquantitative method to evaluate the cerebral blood flow. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparison of standard- and low-tube voltage 320-detector row volume CT angiography in detection of intracranial aneurysms with digital subtraction angiography as gold standard.

PubMed

Sun, Gang; Ding, Juan; Lu, Yang; Li, Min; Li, Li; Li, Guo-ying; Zhang, Xu-ping

2012-03-01

The aim of this study was to prospectively assess the effect of low-tube voltage (80 kVp) 320-detector row volume computed tomographic (CT) angiography (L-VCTA) in the detection of intracranial aneurysms, with three-dimensional (3D) spin digital subtraction angiography (DSA) as the gold standard. Forty-eight patients with clinically suspected subarachnoid hemorrhages were divided into two groups. One group underwent L-VCTA and DSA, while the other group underwent conventional-tube voltage (120 kVp) volume CT angiography (C-VCTA) and DSA. Vascular enhancement, image quality, detection accuracy of aneurysms, and radiation dose were compared between the two groups. For objective image quality, the L-VCTA group had higher mean vessel attenuation, correlated with higher image noise and lower signal-to-noise ratio, than the C-VCTA group. For subjective image quality, there were no significant differences between the two groups regarding scores for arterial enhancement, depiction of small arterial detail, interference of venous structures, and overall image quality scores. The mean effective dose for the L-VCTA group was significantly lower than for the C-VCTA group (0.56 ± 0.25 vs 1.84 ± 0.002 mSv), with a reduction of radiation dose of 69.73%. With 3D DSA as the reference standard, the sensitivity, specificity, and accuracy in the L-VCTA and C-VCTA groups were 94.12%, 100%, 94.4% and 100%, 100%, and 100%, respectively. In both groups, there were significant correlations for maximum aneurysm diameter measurements between volume CT angiography and 3D DSA; no statistical difference in the mean maximum diameter of each aneurysm was measured between volume CT angiography and 3D DSA. L-VCTA is helpful in detecting intracranial aneurysms, with results similar to those of 3D DSA, but at a lower radiation dose than C-VCTA. Copyright © 2012 AUR. Published by Elsevier Inc. All rights reserved.

Timely Antecedent CT or MRI Can Help Predict Hemorrhage Site of Posttreatment Head and Neck Cancer, With Digital Subtraction Angiography Used as the Reference Standard.

PubMed

Ku, Yi-Kang; Wong, Yon-Cheong; Fu, Chen-Ju; Tseng, Hsiao-Jung; Wang, Li-Jen; Wang, Chao-Jan; Chin, Shy-Chyi

2016-04-01

We investigated the timing of CT and MRI performed before digital subtraction angiography (DSA) in the prediction of hemorrhage sites in patients with head and neck cancers who present with acute oral or neck bleeding after receiving treatment. A total of 123 DSA examinations that evaluated 123 oral or neck bleeding events in 85 patients were analyzed. The last CT or MRI examinations performed within a time frame of 0-337 days before transarterial embolization were reviewed retrospectively, with three findings (pseudoaneurysm, air-containing necrotic tissue, and residual tumor) used to predict hemorrhage sites. DSA findings of pseudoaneurysm or active contrast extravasation were used as a reference standard. The sensitivity of CT and MRI for correctly predicting hemorrhage sites was used to determine the optimal timing of CT or MRI examinations performed before DSA. A total of 8.9% of the DSA examinations (11/123) had equivocal findings but were followed by another bleeding event for which DSA findings were positive. CT or MRI was statistically significantly better at predicting hemorrhage sites in patients with bleeding events associated with nonhypopharyngeal cancers (p = 0.019) than in those with bleeding events associated with hypopharyngeal cancers. The sensitivity of CT or MRI in the prediction of hemorrhage sites was statistically significantly higher for the common carotid artery and the internal carotid artery when CT or MRI was performed less than 30 days before bleeding events occurred. Prediction of hemorrhagic sites was better with the use of CT angiography than with the use of enhanced CT or MRI, although it was not statistically significant. DSA findings can temporarily be equivocal. CT or MRI examinations performed within 30 days of bleeding events can predict the site of hemorrhage. If no CT or MRI findings from the past 30 days are available, we suggest performing emergent CT angiography for the sake of obtaining better arterial detail.

Pattern fidelity improvement of chemo-epitaxy DSA process for high-volume manufacturing

NASA Astrophysics Data System (ADS)

Muramatsu, Makoto; Nishi, Takanori; You, Gen; Saito, Yusuke; Ido, Yasuyuki; Ito, Kiyohito; Tobana, Toshikatsu; Hosoya, Masanori; Chen, Weichien; Nakamura, Satoru; Somervell, Mark; Kitano, Takahiro

2016-03-01

Directed self-assembly (DSA) is one of the candidates for next generation lithography. Over the past few years, cylindrical and lamellar structures dictated by the block co-polymer (BCP) composition have been investigated for use in patterning contact holes or lines, and, Tokyo Electron Limited (TEL is a registered trademark or a trademark of Tokyo Electron Limited in Japan and /or other countries.) has presented the evaluation results and the advantages of each-1-5. In this report, we will present the latest results regarding the defect reduction work on a model line/space system. Especially it is suggested that the defectivity of the neutral layer has a large impact on the defectivity of the DSA patterns. Also, LER/LWR reduction results will be presented with a focus on the improvements made during the etch transferring the DSA patterns into the underlayer.

Stable blue phosphorescent organic light emitting devices

DOEpatents

Forrest, Stephen R.; Thompson, Mark; Giebink, Noel

2014-08-26

Novel combination of materials and device architectures for organic light emitting devices is provided. An organic light emitting device, is provided, having an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer includes a host and a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm, and a radiative phosphorescent lifetime less than 1 microsecond. Preferably, the phosphorescent emissive dopant includes a ligand having a carbazole group.

Zinc naphthalenedicarboxylate coordination complex: A promising anode material for lithium and sodium-ion batteries with good cycling stability.

PubMed

Fei, Hailong; Feng, Wenjing; Xu, Tan

2017-02-15

It is important to discover new, cheap and environmental friendly electrode materials with high capacity and good cycling stability for lithium and sodium-ion batteries. Zinc 1,4-naphthalenedicarboxylate was firstly found to be stable anode materials for lithium and sodium-ion batteries. The discharge capacity can be up to 468.9mAhg -1 after 100 cycles at a current density of 100mAg -1 for lithium-ion batteries, while the second discharge capacity of 320.7mAhg -1 was achieved as anode materials for sodium-ion batteries. A possible electrochemical reaction mechanism was discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Variable anodic thermal control coating

NASA Technical Reports Server (NTRS)

Gilliland, C. S.; Duckett, J. (Inventor)

1983-01-01

A process for providing a thermal control solar stable surface coating for aluminum surfaces adapted to be exposed to solar radiation wherein selected values within the range of 0.10 to 0.72 thermal emittance (epsilon sub tau) and 0.2 to 0.4 solar absorptance (alpha subs) are reproducibly obtained by anodizing the surface area in a chromic acid solution for a selected period of time. The rate voltage and time, along with the parameters of initial epsilon sub tau and alpha subs, temperature of the chromic acid solution, acid concentration of the solution and the material anodized determines the final values of epsilon/tau sub and alpha sub S. 9 Claims, 5 Drawing Figures.

Etch challenges for DSA implementation in CMOS via patterning

NASA Astrophysics Data System (ADS)

Pimenta Barros, P.; Barnola, S.; Gharbi, A.; Argoud, M.; Servin, I.; Tiron, R.; Chevalier, X.; Navarro, C.; Nicolet, C.; Lapeyre, C.; Monget, C.; Martinez, E.

2014-03-01

This paper reports on the etch challenges to overcome for the implementation of PS-b-PMMA block copolymer's Directed Self-Assembly (DSA) in CMOS via patterning level. Our process is based on a graphoepitaxy approach, employing an industrial PS-b-PMMA block copolymer (BCP) from Arkema with a cylindrical morphology. The process consists in the following steps: a) DSA of block copolymers inside guiding patterns, b) PMMA removal, c) brush layer opening and finally d) PS pattern transfer into typical MEOL or BEOL stacks. All results presented here have been performed on the DSA Leti's 300mm pilot line. The first etch challenge to overcome for BCP transfer involves in removing all PMMA selectively to PS block. In our process baseline, an acetic acid treatment is carried out to develop PMMA domains. However, this wet development has shown some limitations in terms of resists compatibility and will not be appropriated for lamellar BCPs. That is why we also investigate the possibility to remove PMMA by only dry etching. In this work the potential of a dry PMMA removal by using CO based chemistries is shown and compared to wet development. The advantages and limitations of each approach are reported. The second crucial step is the etching of brush layer (PS-r-PMMA) through a PS mask. We have optimized this step in order to preserve the PS patterns in terms of CD, holes features and film thickness. Several integrations flow with complex stacks are explored for contact shrinking by DSA. A study of CD uniformity has been addressed to evaluate the capabilities of DSA approach after graphoepitaxy and after etching.

Use of the dye stain assay and ultraviolet light test for assessing vaginal insertion of placebo-filled applicators before and after sex.

PubMed

Keller, Marla J; Buckley, Niall; Katzen, Lauren L; Walsh, Jennifer; Friedland, Barbara; Littlefield, Sarah; Lin, Juan; Xue, Xiaonan; Cornelison, Terri; Herold, Betsy C; Einstein, Mark H

2013-12-01

Applicator dye staining and ultraviolet (UV) light have been used in trials to measure adherence, but not in the setting of before and after sex gel dosing (BAT-24). This study was designed to determine if semen or presex gel dosing impacts the sensitivity and specificity of a dye stain assay (DSA) for measuring vaginal insertion of placebo-filled applicators with BAT-24 dosing. Healthy monogamous couples received Microlax-type applicators (Tectubes, Åstorp, Sweden) filled with hydroxyethylcelluose placebo gel. Women were instructed to vaginally insert 1 dose of gel before and a second dose after sex and to return applicators within 48 hours after sex. Applicators were stained to detect semen, followed by UV then DSA, and scored by 2 readers. Positive and negative controls were randomly included in applicator batches. Fifteen couples completed the study. Each woman returned at least 6 applicators over a 30-day period. The sensitivity for insertion of postsex applicators was higher for UV (97%) compared with DSA (90%), and the specificity was similar (≥96%). For presex applicators, the sensitivity and specificity were higher for DSA (100%) compared with UV testing (87% sensitivity, 96% specificity). Among returned postsex applicators, 95% tested positive by UV compared with 87% by DSA. Agreement between readers was significantly better on the presex applicators for DSA than for UV, and for postsex readings, agreement was less than half that for UV, although the results were not statistically significant. Applicator tests are feasible for measuring adherence in trials with gel dosing before and after sex.

Interface chemistry engineering for stable cycling of reduced GO/SnO2 nanocomposites for lithium ion battery.

PubMed

Wang, Lei; Wang, Dong; Dong, Zhihui; Zhang, Fengxing; Jin, Jian

2013-04-10

From the whole anode electrode of view, we report in this work a system-level strategy of fabrication of reduced graphene oxide (RGO)/SnO2 composite-based anode for lithium ion battery (LIB) to enhance the capacity and cyclic performance of SnO2-based electrode materials. RGO/SnO2 composite was first coated by a nanothick polydopamine (PD) layer and the PD-coated RGO/SnO2 composite was then cross-linked with poly(acrylic acid) (PAA) that was used as a binder to accomplish a whole anode electrode. The cross-link reaction between PAA and PD produced a robust network in the anode system to stabilize the whole anode during cycling. As a result, the designed anode exhibits an outstanding energy capacity up to 718 mAh/g at current density of 100 mA/g after 200 cycles and a good rate performance of 811, 700, 641, and 512 mAh/g at current density of 100, 250, 500, and 1000 mA/g, respectively. Fourier transform IR spectra confirm the formation of cross-link reaction and the stability of the robust network after long-term cycling. Our results indicate the importance of designing interfaces in anode system on achieving improved performance of electrode of LIBs.

Scallop-Inspired Shell Engineering of Microparticles for Stable and High Volumetric Capacity Battery Anodes.

PubMed

Zhang, Xinghao; Guo, Ruiying; Li, Xianglong; Zhi, Linjie

2018-06-01

Building stable and efficient electron and ion transport pathways are critically important for energy storage electrode materials and systems. Herein, a scallop-inspired shell engineering strategy is proposed and demonstrated to confine high volume change silicon microparticles toward the construction of stable and high volumetric capacity binder-free lithium battery anodes. As for each silicon microparticle, the methodology involves an inner sealed but adaptable overlapped graphene shell, and an outer open hollow shell consisting of interconnected reduced graphene oxide, mimicking the scallop structure. The inner closed shell enables simultaneous stabilization of the interfaces of silicon with both carbon and electrolyte, substantially facilitates efficient and rapid transport of both electrons and lithium ions from/to silicon, the outer open hollow shell creates stable and robust transport paths of both electrons and lithium ions throughout the electrode without any sophisticated additives. The resultant self-supported electrode has achieved stable cycling with rapidly increased coulombic efficiency in the early stage, superior rate capability, and remarkably high volumetric capacity upon a facile pressing process. The rational design and engineering of graphene shells of the silicon microparticles developed can provide guidance for the development of a wide range of other high capacity but large volume change electrochemically active materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Flexible Solid Electrolyte Interphase Layer for Long-Life Lithium Metal Anodes.

PubMed

Li, Nian-Wu; Shi, Yang; Yin, Ya-Xia; Zeng, Xian-Xiang; Li, Jin-Yi; Li, Cong-Ju; Wan, Li-Jun; Wen, Rui; Guo, Yu-Guo

2018-02-05

Lithium (Li) metal is a promising anode material for high-energy density batteries. However, the unstable and static solid electrolyte interphase (SEI) can be destroyed by the dynamic Li plating/stripping behavior on the Li anode surface, leading to side reactions and Li dendrites growth. Herein, we design a smart Li polyacrylic acid (LiPAA) SEI layer high elasticity to address the dynamic Li plating/stripping processes by self-adapting interface regulation, which is demonstrated by in situ AFM. With the high binding ability and excellent stability of the LiPAA polymer, the smart SEI can significantly reduce the side reactions and improve battery safety markedly. Stable cycling of 700 h is achieved in the LiPAA-Li/LiPAA-Li symmetrical cell. The innovative strategy of self-adapting SEI design is broadly applicable, providing opportunities for use in Li metal anodes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recovery of lead from smelting fly ash of waste lead-acid battery by leaching and electrowinning.

PubMed

Chen, Chuh-Shun; Shih, Yu-Jen; Huang, Yao-Hui

2016-06-01

Fly ash that was enriched with lead (Pb), formed as an intermediate in waste lead-acid battery (WLAB) smelting, was recycled by the hydro-electrometallurgy. Characterization of fly ash thereof indicated that the Pb was in the forms of PbSO4 (anglesite) and Pb2OSO4 (lanarkite). Nitric acid and sodium hydroxide were firstly used to study the leaching of the fly ash sample, which was affected by leachant dosage and solid-to-liquid ratio (S/L). At an S/L of 60gL(-1), the leachability of Pb was 43% and 67% in 2M acidic and basic solutions, respectively, based on an average 70wt% of Pb in the original fly ash. Anglesite was completely soluble in NaOH and lanarkite was mildly soluble in HNO3. Pb was recovered from the pregnant leach solution within an electrolytic cell constructed with graphite or RuO2/IrO2-coated titanium (Ti-DSA) anodes and a stainless steel cathode. Properties of anodes deposited with lead dioxides were analyzed by cyclic voltammetry. The optimized parameters of electrowinning were 2M NaOH leachant, a current density of 0.75Adm(-2) and an electrolytic process duration of 120min, which yielded a Pb removal of higher than 99% and a specific energy consumption of 0.57Whg(-1). This process constitutes an eco-friendly and economic alternative to the presently utilized secondary pyrometallurgy for treating lead-containing fly ash. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design features of implants for direct skeletal attachment of limb prostheses

PubMed Central

Pitkin, M.

2013-01-01

In direct skeletal attachment (DSA) of limb prostheses, a construct is implanted into an amputee’s residuum bone and protrudes out of the residuum’s skin. This technology represents an alternative to traditional suspension of prostheses via various socket systems, with clear indications when the sockets cannot be properly fitted. Contemporary DSA was invented in the 1990s, and several implant systems have been introduced since then. The current review is intended to compare the design features of implants for DSA whose use in humans or in animal studies has been reported in the literature. PMID:23554122

Effects of Heat Treatment on the Discharge Behavior of Mg-6wt.%Al-1wt.%Sn Alloy as Anode For Magnesium-Air Batteries

NASA Astrophysics Data System (ADS)

Xiong, Hanqing; Zhu, Hualong; Luo, Jie; Yu, Kun; Shi, Chunli; Fang, Hongjie; Zhang, Yu

2017-05-01

Mg-6wt.%Al-1wt.%Sn alloys under different conditions are prepared. Primary magnesium-air batteries are assembled using such experimental Mg-Al-Sn alloys as anodes. The discharge behaviors of different alloys are investigated in 3.5 wt.% NaCl solution. The results show that the solution treatment can facilitate the homogeneous distribution of alloy elements and reduce the accumulation of discharge products. The magnesium-air battery based on the solution-treated Mg-Al-Sn anode presents higher operating voltage and more stable discharge process than those on the as-cast and the aged ones. Although the solution treatment cannot effectively improve the capacity density and the anodic efficiency of the experimental Mg-Al-Sn alloy, it is an effective approach to increasing the power and the energy density during discharge process. Especially at the applied current density of 30 mA cm-2 for 5 h, the solution-treated anode supplies 1.212 V average operating voltage, the anode energy density reaches 1527.2 mWhg-1, while the cast one is 1481.3 mWhg-1 and the aged one is 1478.8 mWhg-1.

Sodium fluoride-assisted modulation of anodized TiO₂ nanotube for dye-sensitized solar cells application.

PubMed

Yun, Jung-Ho; Ng, Yun Hau; Ye, Changhui; Mozer, Attila J; Wallace, Gordon G; Amal, Rose

2011-05-01

This work reports the use of sodium fluoride (in ethylene glycol electrolyte) as the replacement of hydrofluoric acid and ammonium fluoride to fabricate long and perpendicularly well-aligned TiO₂ nanotube (TNT) (up to 21 μm) using anodization. Anodizing duration, applied voltage and electrolyte composition influenced the geometry and surface morphologies of TNT. The growth mechanism of TNT is interpreted by analyzing the current transient profile and the total charge density generated during anodization. The system with low water content (2 wt %) yielded a membrane-like mesoporous TiO₂ film, whereas high anodizing voltage (70 V) resulted in the unstable film of TNT arrays. An optimized condition using 5 wt % water content and 60 V of anodizing voltage gave a stable array of nanotube with controllable length and pore diameter. Upon photoexcitation, TNTs synthesized under this condition exhibited a slower charge recombination rate as nanotube length increased. When made into cis-diisothiocyanato-bis(2,2̀-bipyridyl-4,4̀-dicarboxylato) ruthenium(II) bis (tetrabutyl-ammonium)(N719) dye-sensitized solar cells, good device efficiency at 3.33 % based on the optimized TNT arrays was achieved with longer electron time compared with most mesoporous TiO₂ films.

Effects of Loading Frequency on Fatigue Behavior, Residual Stress, and Microstructure of Deep-Rolled Stainless Steel AISI 304 at Elevated Temperatures

NASA Astrophysics Data System (ADS)

Nikitin, I.; Juijerm, P.

2018-02-01

The effects of loading frequency on the fatigue behavior of non-deep-rolled (NDR) and deep-rolled (DR) austenitic stainless steel AISI 304 were systematically clarified at elevated temperatures, especially at temperatures exhibiting the dynamic strain aging (DSA) phenomena. Tension-compression fatigue tests were performed isothermally at temperatures of 573 K and 773 K (300 °C and 500 °C) with different loading frequencies of 5, 0.5, 0.05, and 0.005 Hz. For the DR condition, the residual stresses and work-hardening states will be presented. It was found that DSA would be detected at appropriate temperatures and deformation rates. The cyclic deformation curves and the fatigue lives of the investigated austenitic stainless steel AISI 304 are considerably affected by the DSA, especially on the DR condition having high dislocation densities at the surface and in near-surface regions. In the temperature range of the DSA, residual stresses and work-hardening states of the DR condition seem to be stabilized. The microstructural alterations were investigated by transmission electron microscopy (TEM). At an appropriate temperature with low loading frequency, the plastic deformation mechanism shifted from a wavy slip manner to a planar slip manner in the DSA regimes, whereas the dislocation movements were obstructed.

Representing situation awareness in collaborative systems: a case study in the energy distribution domain.

PubMed

Salmon, P M; Stanton, N A; Walker, G H; Jenkins, D; Baber, C; McMaster, R

2008-03-01

The concept of distributed situation awareness (DSA) is currently receiving increasing attention from the human factors community. This article investigates DSA in a collaborative real-world industrial setting by discussing the results derived from a recent naturalistic study undertaken within the UK energy distribution domain. The results describe the DSA-related information used by the networks of agents involved in the scenarios analysed, the sharing of this information between the agents and the salience of different information elements used. Thus, the structure, quality and content of each network's DSA is discussed, along with the implications for DSA theory. The findings reinforce the notion that when viewing situation awareness (SA) in collaborative systems, it is useful to focus on the coordinated behaviour of the system itself, rather than on the individual as the unit of analysis and suggest that the findings from such assessments can potentially be used to inform system, procedure and training design. SA is a critical commodity for teams working in industrial systems and systems, procedures and training programmes should be designed to facilitate efficient system SA acquisition and maintenance. This article presents approaches for describing and understanding SA during real-world collaborative tasks, the outputs from which can potentially be used to inform system, training programmes and procedure design.

The costs and effects of contrast-enhanced magnetic resonance angiography and digital substraction angiography on quality of life in patients with peripheral arterial disease.

PubMed

Bosma, Jan; Dijksman, Lea M; Lam, Kayan; Wisselink, Willem; van Swijndregt, Alexander D Montauban; Vahl, Anco

2014-04-01

Contrast-enhanced magnetic resonance angiography (MRA) and intra-arterial digital subtraction angiography (DSA) both have a high diagnostic performance in the imaging of peripheral arterial occlusive disease (PAOD). However, little is known about the effects of initial, preoperative imaging using MRA or DSA on quality of life (QoL) in relation to costs (cost-utility). To compare cost-utility of treatment strategies using either MRA or DSA as the principal imaging tool, related to QoL, in patients with PAOD. In a prospective subgroup analysis of patients randomized between MRA and DSA (n = 79) for preoperative imaging, QoL questionnaires (SF-36) were obtained at randomization and at 4-month follow-up. Cost-effectiveness from hospital perspective was subsequently compared between groups and the difference in gained or lost QoL per € spent assessed using bootstrap analysis. No difference in quality of life was found. A treatment trajectory employing MRA as the principal imaging modality was almost 20% cheaper, leading to a better cost-utility ratio in favor of MRA. A treatment plan for peripheral arterial occlusive disease employing MRA versus DSA as the principal imaging modality yields a better cost/QoL ratio for MRA.

Obliterative portal venopathy: A histopathologic finding associated with chronic antibody-mediated rejection in pediatric liver allografts.

PubMed

Guerra, Marjorie-Anne R; Naini, Bita V; Scapa, Jason V; Reed, Elaine F; Busuttil, Ronald W; Cheng, Elaine Y; Farmer, Douglas G; Vargas, Jorge H; Venick, Robert S; McDiarmid, Sue V; Wozniak, Laura J

2018-03-01

The significance of post-transplant HLA DSA and chronic AMR in LT is an emerging field of study. Although OPV has previously been described as a histopathologic finding in DSA-positive adult LT recipients, it was not included in the recent Banff criteria for chronic AMR. Our aim was to describe the association between OPV and chronic AMR in pediatric LT recipients. A retrospective review of 67 liver biopsies performed between November 2014 and April 2016 in 45 pediatric LT recipients identified four patients with OPV. Clinical status, liver biochemistry, the presence of DSA, and available non-HLA antibody testing, as well as histopathologic features of chronic AMR, were assessed. All four patients with OPV had class II DSA and histopathologic features of chronic AMR based on the Banff criteria. Two patients were noted to have non-HLA antibodies. Three patients are undergoing treatment with IVIG but have persistent DSA. Two patients have graft failure and are awaiting retransplantation. In conclusion, OPV is a histopathologic finding associated with chronic AMR in pediatric LT recipients. Further studies are needed to elucidate whether OPV is reversible and/or amenable to medical therapy. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Arterial imaging in patients with lower extremity ischemia and diabetes mellitus.

PubMed

Pomposelli, Frank

2010-09-01

Precise, comprehensive imaging of the arterial circulation is the cornerstone of successful revascularization of the ischemic extremity in patients with diabetes mellitus. Arterial imaging is challenging in these patients because the disease is often multisegmental with a predilection for the distal tibial and peroneal arteries. Occlusive lesions and the arterial wall itself are often calcified and patients presenting with ischemic complications frequently have underlying renal insufficiency. Intra-arterial digital subtraction angiography (DSA), contrast enhanced magnetic resonance angiography (MRA), and more recently, computerized tomographic angiography (CTA) have been used as imaging modalities in lower extremity ischemia. Each has specific advantages and shortcomings in this patient population, which will be summarized and contrasted in this review. DSA is an invasive technique most often performed from a femoral arterial puncture and requires the injection of arterial contrast, which can occasionally cause allergic reactions. In patients with pre-existing renal insufficiency, contrast infusion can result in worsening renal failure; although usually self-limited, it may occasionally require hemodialysis, especially in patients with diabetes. However, DSA provides the highest degree of spatial resolution and image quality. It is also the only modality in which the diagnosis and treatment of arterial disease can be performed simultaneously. MRA is noninvasive, and when enhanced with gadolinium contrast injection provides arterial images of comparable quality to DSA and in some circumstances may uncover distal arterial targets not visualized on DSA. However, spatial resolution is inferior to DSA and erroneous interpretations due to acquisition artifacts are common. Specialized equipment and imaging techniques are necessary to minimize their occurrence in the distal lower extremity. In addition, due to the risk of inducing nephrogenic systemic fibrosis, gadolinium-enhanced MRA cannot be used in patients with renal insufficiency. CTA is noninvasive and rapidly performed, with better spatial resolution than MRA, but requires the largest volume of contrast infusion, exposes patients to high-doses of radiation, and is subject to interpretive error due to reconstruction artifacts especially in heavily calcified arteries, limiting its usefulness in many patients with diabetes. For patients in whom the planned intervention is a surgical bypass, DSA and MRA will provide high quality images of the lower extremity arterial anatomy. For patients in whom a catheter-based intervention is the likely treatment, a diagnostic DSA immediately followed by a catheter-based treatment in the same procedure is the preferred approach. In patients with pre-existing renal dysfunction, in which gadolinium-enhanced MRA is contraindicated, DSA or CTA can be performed. However, patients should have an infusion of intravenous normal saline solution or sodium bicarbonate before the procedure to reduce the incidence of contrast-induced nephropathy. Copyright © 2010. Published by Mosby, Inc.

Reconstruction of Mini-Hollow Polyhedron Mn2O3 Derived from MOFs as a High-Performance Lithium Anode Material.

PubMed

Cao, Kangzhe; Jiao, Lifang; Xu, Hang; Liu, Huiqiao; Kang, Hongyan; Zhao, Yan; Liu, Yongchang; Wang, Yijing; Yuan, Huatang

2016-03-01

A mini-hollow polyhedron Mn 2 O 3 is used as the anode material for lithium-ion batteries. Benefiting from the small interior cavity and intrinsic nanosize effect, a stable reconstructed hierarchical nanostructure is formed. It has excellent energy storage properties, exhibiting a capacity of 760 mAh g -1 at 2 A g -1 after 1000 cycles. This finding offers a new perspective for the design of electrodes with large energy storage.

Nanoporous hard data: optical encoding of information within nanoporous anodic alumina photonic crystals

NASA Astrophysics Data System (ADS)

Santos, Abel; Law, Cheryl Suwen; Pereira, Taj; Losic, Dusan

2016-04-01

Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for developing advanced nanophotonic tools for a wide range of applications, including sensing, photonic tagging, self-reporting drug releasing systems and secure encoding of information.Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for developing advanced nanophotonic tools for a wide range of applications, including sensing, photonic tagging, self-reporting drug releasing systems and secure encoding of information. Electronic supplementary information (ESI) available: Further details about anodisation profiles, SEM cross-section images, digital pictures, transmission spectra, photonic barcodes and ASCII codes of the different NAA photonic crystals fabricated and analysed in our study. See DOI: 10.1039/c6nr01068g

Multishelled Si@Cu Microparticles Supported on 3D Cu Current Collectors for Stable and Binder-free Anodes of Lithium-Ion Batteries.

PubMed

Zhang, Zailei; Wang, Zhong Lin; Lu, Xianmao

2018-04-24

Silicon has proved to be a promising anode material of high-specific capacity for the next-generation lithium ion batteries (LIBs). However, during repeated discharge/charge cycles, Si-based electrodes, especially those in microscale size, pulverize and lose electrical contact with the current collectors due to large volume expansion. Here, we introduce a general method to synthesize Cu@M (M = Si, Al, C, SiO 2 , Si 3 N 4 , Ag, Ti, Ta, SnIn 2 O 5 , Au, V, Nb, W, Mg, Fe, Ni, Sn, ZnO, TiN, Al 2 O 3 , HfO 2 , and TiO 2 ) core-shell nanowire arrays on Cu substrates. The resulting Cu@Si nanowire arrays were employed as LIB anodes that can be reused via HCl etching and H 2 -reduction. Multishelled Cu@Si@Cu microparticles supported on 3D Cu current collectors were further prepared as stable and binder-free LIB anodes. This 3D Cu@Si@Cu structure allows the interior conductive Cu network to effectively accommodate the volume expansion of the electrode and facilitates the contact between the Cu@Si@Cu particles and the current collectors during the repeated insertion/extraction of lithium ions. As a result, the 3D Cu@Si@Cu microparticles at a high Si-loading of 1.08 mg/cm 2 showed a capacity retention of 81% after 200 cycles. In addition, charging tests of 3D Cu@Si@Cu-LiFePO 4 full cells by a triboelectric nanogenerator with a pulsed current demonstrated that LIBs with silicon anodes can effectively store energy delivered by mechanical energy harvesters.

Towards Stable Lithium-Sulfur Batteries with a Low Self-Discharge Rate: Ion Diffusion Modulation and Anode Protection.

PubMed

Xu, Wen-Tao; Peng, Hong-Jie; Huang, Jia-Qi; Zhao, Chen-Zi; Cheng, Xin-Bing; Zhang, Qiang

2015-09-07

The self-discharge of a lithium-sulfur cell decreases the shelf-life of the battery and is one of the bottlenecks that hinders its practical applications. New insights into both the internal chemical reactions in a lithium-sulfur system and effective routes to retard self-discharge for highly stable batteries are crucial for the design of lithium-sulfur cells. Herein, a lithium-sulfur cell with a carbon nanotube/sulfur cathode and lithium-metal anode in lithium bis(trifluoromethanesulfonyl)imide/1,3-dioxolane/dimethyl ether electrolyte was selected as the model system to investigate the self-discharge behavior. Both lithium anode passivation and polysulfide anion diffusion suppression strategies are applied to reduce self-discharge of the lithium-sulfur cell. When the lithium-metal anode is protected by a high density passivation layer induced by LiNO3 , a very low shuttle constant of 0.017 h(-1) is achieved. The diffusion of the polysulfides is retarded by an ion-selective separator, and the shuttle constants decreased. The cell with LiNO3 additive maintained a discharge capacity of 97 % (961 mAh g(-1) ) of the initial capacity after 120 days at open circuit, which was around three times higher than the routine cell (32 % of initial capacity, corresponding to 320 mAh g(-1) ). It is expected that lithium-sulfur batteries with ultralow self-discharge rates may be fabricated through a combination of anode passivation and polysulfide shuttle control, as well as optimization of the lithium-sulfur cell configuration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Retention of Sputtered Molybdenum on Ion Engine Discharge Chamber Surfaces

NASA Technical Reports Server (NTRS)

Sovey, James S.; Dever, Joyce A.; Power, John L.

2001-01-01

Grit-blasted anode surfaces are commonly used in ion engines to ensure adherence of sputtered coatings. Next generation ion engines will require higher power levels, longer operating times, and thus there will likely be thicker sputtered coatings on their anode surfaces than observed to date on 2.3 kW-class xenon ion engines. The thickness of coatings on the anode of a 10 kW, 40-centimeter diameter thruster, for example, may be 22 micrometers or more after extended operation. Grit-blasted wire mesh, titanium, and aluminum coupons were coated with molybdenum at accelerated rates to establish coating stability after the deposition process and after thermal cycling tests. These accelerated deposition rates are roughly three orders of magnitude more rapid than the rates at which the screen grid is sputtered in a 2.3 kW-class, 30-centimeter diameter ion engine. Using both RF and DC sputtering processes, the molybdenum coating thicknesses ranged from 8 to 130 micrometers, and deposition rates from 1.8 micrometers per hour to 5.1 micrometers per hour. In all cases, the molybdenum coatings were stable after the deposition process, and there was no evidence of spalling of the coatings after 20 cycles from about -60 to +320 C. The stable, 130 micrometer molybdenum coating on wire mesh is 26 times thicker than the thickest coating found on the anode of a 2.3 kW, xenon ion engine that was tested for 8200 hr. Additionally, this coating on wire mesh coupon is estimated to be a factor of greater than 4 thicker than one would expect to obtain on the anode of the next generation ion engine which may have xenon throughputs as high as 550 kg.

Comparison of remnant size in embolized intracranial aneurysms measured at follow-up with DSA and MRA.

PubMed

Serafin, Zbigniew; Strześniewski, Piotr; Lasek, Władysław; Beuth, Wojciech

2012-12-01

The possibility of recanalization and the need for retreatment are the most important limitations of intracranial aneurysm embolization. The purpose of the study was to compare the size of aneurysm remnants measured at follow-up with three-dimensional digital subtracted angiography (3D-DSA) and magnetic resonance angiography (MRA). Twenty-six aneurysms were found incompletely occluded in 72 consecutively examined patients at a follow-up after 3 months. The diameters and volume of aneurysm remnants were compared between 3D-DSA, time-of-flight MRA (TOF-MRA), contrast-enhanced TOF-MRA (CE-TOF-MRA), and contrast-enhanced MRA (CE-MRA) at 1.5 T. There was a significant correlation between remnant volumes calculated based on 3D-DSA and all MRA modalities. The intraobserver variability of the measurements ranged from 3.4 to 4.1 % and the interobserver variability from 5.8 to 7.3 %. There were no significant differences in the variability between the techniques. The mean residual filling volume ranged from 16.3 ± 19.0 mm(3) in TOF-MRA to 30.5 ± 44.6 mm(3) in 3D-DSA (P < 0.04). Significant differences were found in the volumes measured with 3D-DSA and CE-MRA as compared to TOF-MRA and CE-TOF-MRA (P < 0.01). There was a moderate significant correlation between the residual filling and the relative error of measurement in the case of TOF-MRA and CE-TOF-MRA. TOF-MRA seems to underestimate the size of aneurysm remnants detected at follow-up and should not be used as a sole imaging method to decide on re-embolization.

Optimal MRI sequence for identifying occlusion location in acute stroke: which value of time-resolved contrast-enhanced MRA?

PubMed

Le Bras, A; Raoult, H; Ferré, J-C; Ronzière, T; Gauvrit, J-Y

2015-06-01

Identifying occlusion location is crucial for determining the optimal therapeutic strategy during the acute phase of ischemic stroke. The purpose of this study was to assess the diagnostic efficacy of MR imaging, including conventional sequences plus time-resolved contrast-enhanced MRA in comparison with DSA for identifying arterial occlusion location. Thirty-two patients with 34 occlusion levels referred for thrombectomy during acute cerebral stroke events were consecutively included from August 2010 to December 2012. Before thrombectomy, we performed 3T MR imaging, including conventional 3D-TOF and gradient-echo T2 sequences, along with time-resolved contrast-enhanced MRA of the extra- and intracranial arteries. The 3D-TOF, gradient-echo T2, and time-resolved contrast-enhanced MRA results were consensually assessed by 2 neuroradiologists and compared with prethrombectomy DSA results in terms of occlusion location. The Wilcoxon test was used for statistical analysis to compare MR imaging sequences with DSA, and the κ coefficient was used to determine intermodality agreement. The occlusion level on the 3D-TOF and gradient-echo T2 images differed significantly from that of DSA (P < .001 and P = .002, respectively), while no significant difference was observed between DSA and time-resolved contrast-enhanced MRA (P = .125). κ coefficients for intermodality agreement with DSA (95% CI, percentage agreement) were 0.43 (0.3%-0.6; 62%), 0.32 (0.2%-0.5; 56%), and 0.81 (0.6%-1.0; 88%) for 3D-TOF, gradient-echo T2, and time-resolved contrast-enhanced MRA, respectively. The time-resolved contrast-enhanced MRA sequence proved reliable for identifying occlusion location in acute stroke with performance superior to that of 3D-TOF and gradient-echo T2 sequences. © 2015 by American Journal of Neuroradiology.

Interest of HYPR flow dynamic MRA for characterization of cerebral arteriovenous malformations: comparison with TRICKS MRA and catheter DSA.

PubMed

Dautry, Raphaël; Edjlali, Myriam; Roca, Pauline; Rabrait, Cécile; Wu, Yijing; Johnson, Kevin; Wieben, Olivier; Trystram, Denis; Rodriguez-Régent, Christine; Alshareef, Fawaz; Turski, Patrick; Meder, Jean-François; Naggara, Olivier; Oppenheim, Catherine

2015-11-01

HYPR flow is a 3D dynamic contrast-enhanced MRA technique providing isotropic sub-millimetre resolution with half-second temporal resolution. We compared HYPR flow and time-resolved imaging of contrast kinetics (TRICKS) MRA for the characterization of cerebral arteriovenous malformations (cAVMs), using catheter DSA as reference. Twenty-two patients underwent HYPR flow and TRICKS MRA within 15 days of DSA. HYPR flow and TRICKS datasets were reviewed separately by two readers for image quality, Spetzler-Martin grade, venous ectasia, and deep venous drainage. Image quality was better for HYPR flow than for TRICKS (narrower full width at half maximum; larger arterial diagnostic window; greater number of arterial frames, P ≤ 0.05). Using HYPR flow, inter-reader agreement was excellent for all cAVM characteristics. The agreement with DSA for the overall Spetzler-Martin grade was excellent for HYPR flow (ICC = 0.96 and 0.98, depending on the reader) and TRICKS (ICC = 0.82 and 0.95). In comparison to TRICKS, HYPR flow showed higher concordance with DSA for the identification of venous ectasia and deep venous drainage. Owing to an excellent agreement with DSA with respect to depiction of the vascular architecture of cAVMs, HYPR flow could be useful for the non-invasive characterization of cAVMs. • Dynamic MRA is used for cerebral AVM depiction and follow-up • HYPR flow is a new, highly-resolved dynamic MRA sequence • HYPR flow provides whole brain coverage • HYPR flow provides excellent agreement with the Spetzler-Martin grade • Compared to TRICKS MRA, HYPR flow improves cerebral AVM characterization.

Non-contrast-enhanced MRA of renal artery stenosis: validation against DSA in a porcine model.

PubMed

Bley, T A; François, C J; Schiebler, M L; Wieben, O; Takei, N; Brittain, J H; Del Rio, A Munoz; Grist, T M; Reeder, S B

2016-02-01

To compare 3D-inversion-recovery balanced steady-state free precession (IR-bSSFP) non-contrast-enhanced magnetic resonance angiography (MRA) with 3D-contrast-enhanced MRA (CE-MRA) for assessment of renal artery stenosis (RAS) using digital subtraction angiography (DSA) as the reference standard. Bilateral RAS were surgically created in 12 swine. IR-bSSFP and CE-MRA were acquired at 1.5 T and compared to rotational DSA. Three experienced cardiovascular radiologists evaluated the IR-bSSFP and CE-MRA studies independently. Linear regression models were used to calibrate and assess the accuracy of IR-bSSFP and CE-MRA, separately, against DSA. The coefficient of determination and Cohen's kappa coefficient were also generated. Calibration of the three readers' RAS grading revealed R(2) values of 0.52, 0.37 and 0.59 for NCE-MRA and 0.48, 0.53 and 0.71 for CE-MRA. Inter-rater agreement demonstrated Cohen's kappa values ranging from 0.25 to 0.65. Distal renal artery branch vessels were visible to a significantly higher degree with NCE-MRA compared to CE-MRA (p < 0.001). Image quality was rated excellent for both sequences, although image noise was higher with CE-MRA (p < 0.05). In no cases did noise interfere with image interpretation. In a well-controlled animal model of surgically induced RAS, IR-bSSFP based NCE-MRA and CE-MRA accurately graded RAS with a tendency for stenosis overestimation, compared to DSA. • IR-bSSFP and CE-MRA are accurate methods for diagnosis of renal artery stenosis • IR-bSSFP and CE-MRA demonstrate excellent agreement with DSA • Both IR-bSSFP and CE-MRA have a tendency to overestimate renal artery stenosis.

Comparison of ferumoxytol-enhanced MRA with conventional angiography for assessment of severity of transplant renal artery stenosis.

PubMed

Fananapazir, Ghaneh; Bashir, Mustafa R; Corwin, Michael T; Lamba, Ramit; Vu, Catherine T; Troppmann, Christoph

2017-03-01

To determine the accuracy of ferumoxytol-enhanced magnetic resonance angiography (MRA) in assessing the severity of transplant renal artery stenosis (TRAS), using digital subtraction angiography (DSA) as the reference standard. Our Institutional Review Board approved this retrospective, Health Insurance Portability and Accountability Act-compliant study. Thirty-three patients with documented clinical suspicion for TRAS (elevated serum creatinine, refractory hypertension, edema, and/or audible bruit) and/or concerning sonographic findings (elevated renal artery velocity and/or intraparenchymal parvus tardus waveforms) underwent a 1.5T MRA with ferumoxytol prior to DSA. All DSAs were independently reviewed by an interventional radiologist and served as the reference standard. The MRAs were reviewed by three readers who were blinded to the ultrasound and DSA findings for the presence and severity of TRAS. Sensitivity, specificity, and accuracy for identifying substantial stenoses (>50%) were determined. Intraclass correlation coefficients (ICCs) were calculated among readers. Mean differences between the percent stenosis from each MRA reader and DSA were calculated. On DSA, a total of 42 stenoses were identified in the 33 patients. The sensitivity, specificity, and accuracy of MRA in detecting substantial stenoses were 100%, 75-87.5%, and 95.2-97.6%, respectively, among the readers. There was excellent agreement among readers as to the percent stenosis (ICC = 0.82). MRA overestimated the degree of stenosis by 3.9-9.6% compared to DSA. Ferumoxytol-enhanced MRA provides high sensitivity, specificity, and accuracy for determining the severity of TRAS. Our results suggest that it can potentially be used as a noninvasive examination following ultrasound to reduce the number of unnecessary conventional angiograms. 3 J. Magn. Reson. Imaging 2017;45:779-785. © 2016 International Society for Magnetic Resonance in Medicine.

CE-MRA for follow-up of aneurysms post stent-assisted coiling.

PubMed

Agid, R; Schaaf, M; Farb, Ri

2012-09-01

This study compared the accuracy of contrast-enhanced MR angiography (CE-MRA) to intra-arterial cerebral angiography (IA-DSA) for assessment of intracranial aneurysms after stent-assisted coiling and to check if the presence of a stent in the parent artery diminishes the accuracy of CE-MRA. Consecutive patients with cerebral aneurysms treated by stent-assisted coiling were evaluated retrospectively. Matching follow-up CE-MRA and IA-DSA were evaluated separately. Evaluation included the presence of aneurysmal remnant, patency and stenosis of parent artery. Twenty-seven patients with 28 aneurysms and 33 matched CE-MRA and IA-DSA studies were evaluated. Nineteen aneurysmal remnants were seen on CE-MRA and 16 on IA-DSA. CE-MRA diagnosed three aneurysmal remnants not appreciated on IA-DSA. Five other remnants were larger on CE-MRA than IA-DSA. None of the remnants were missed on CE-MRA. Parent arteries were patent on both modalities. CE-MRA showed false stenosis of the stented artery in six cases and exaggerated stenosis in two. In 18 cases, CE-MRA showed a short focal "pseudo-stenosis" where the stent's marker bands were located. This was noted whenever the stent's marker bands were located in an artery with luminal diameter ≤2 mm and was called "marker band effect". CE-MRA is an accurate technique for follow-up of aneurysms post stent-assisted coiling with excellent depiction of remnants in spite of the presence of a stent. Apparent stenosis of the stented parent artery on CE-MRA is often false or exaggerated. "Marker band effect" should be recognized as an artifact that appears when stent's marker bands are in a small artery.

CE-MRA for Follow-up of Aneurysms Post Stent-Assisted Coiling

PubMed Central

Agid, R.; Schaaf, M.; Farb, RI.

2012-01-01

Summary This study compared the accuracy of contrast-enhanced MR angiography (CE-MRA) to intra-arterial cerebral angiography (IA-DSA) for assessment of intracranial aneurysms after stent-assisted coiling and to check if the presence of a stent in the parent artery diminishes the accuracy of CE-MRA. Consecutive patients with cerebral aneurysms treated by stent-assisted coiling were evaluated retrospectively. Matching follow-up CE-MRA and IA-DSA were evaluated separately. Evaluation included the presence of aneurysmal remnant, patency and stenosis of parent artery. Twenty-seven patients with 28 aneurysms and 33 matched CE-MRA and IA-DSA studies were evaluated. Nineteen aneurysmal remnants were seen on CE-MRA and 16 on IA-DSA. CE-MRA diagnosed three aneurysmal remnants not appreciated on IA-DSA. Five other remnants were larger on CE-MRA than IA-DSA. None of the remnants were missed on CE-MRA. Parent arteries were patent on both modalities. CE-MRA showed false stenosis of the stented artery in six cases and exaggerated stenosis in two. In 18 cases, CE-MRA showed a short focal “pseudo-stenosis” where the stent’s marker bands were located. This was noted whenever the stent’s marker bands were located in an artery with luminal diameter ≤2 mm and was called “marker band effect”. CE-MRA is an accurate technique for follow-up of aneurysms post stent-assisted coiling with excellent depiction of remnants in spite of the presence of a stent. Apparent stenosis of the stented parent artery on CE-MRA is often false or exaggerated. “Marker band effect” should be recognized as an artifact that appears when stent’s marker bands are in a small artery. PMID:22958765

Use of the Dye Stain Assay and Ultraviolet Light Test for Assessing Vaginal Insertion of Placebo-filled Applicators Before and After Sex

PubMed Central

Keller, Marla J.; Buckley, Niall; Katzen, Lauren L.; Walsh, Jennifer; Friedland, Barbara; Littlefield, Sarah; Lin, Juan; Xue, Xiaonan; Cornelison, Terri; Herold, Betsy C.; Einstein, Mark H.

2014-01-01

Background Applicator dye staining and ultraviolet (UV) light have been used in trials to measure adherence, but not in the setting of before and after sex gel dosing (BAT-24). This study was designed to determine if semen or pre-sex gel dosing impacts the sensitivity and specificity of a dye stain assay (DSA) for measuring vaginal insertion of placebo-filled applicators with BAT-24 dosing. Methods Healthy monogamous couples received Microlax®-type applicators filled with hydroxyethylcelluose placebo gel. Women were instructed to vaginally insert one dose of gel before and a second dose after sex and to return applicators within 48 hours after sex. Applicators were stained to detect semen followed by UV then DSA and scored by two readers. Positive and negative controls were randomly included in applicator batches. Results Fifteen couples completed the study. Each female returned at least six applicators over a 30-day period. The sensitivity for insertion of post-sex applicators was higher for UV (97%) compared to DSA (90%) and the specificity was similar (≥96%). For pre-sex applicators, the sensitivity and specificity were higher for DSA (100%) compared to UV testing (87% sensitivity, 96% specificity). Among returned post-sex applicators, 95% tested positive by UV compared to 87% by DSA. Agreement between readers was significantly better on the pre-sex applicators for DSA than for UV and for post-sex readings agreement was less than half that for UV, although the results were not statistically significant. Conclusions Applicator tests are feasible for measuring adherence in trials with gel dosing before and after sex. PMID:24220355

Evaluation of Three Approaches for Assessing Adherence to Vaginal Gel Application in Clinical Trials

PubMed Central

van der Straten, Ariane; Cheng, Helen; Mensch, Barbara; Friedland, Barbara; Katzen, Lauren; Littlefield, Sarah; Buckley, Niall; Espinoza, Lilia; Keller, Marla J.; Herold, Betsy C.; Einstein, Mark H.

2014-01-01

Background: Accurate measurement of adherence to product use is an ongoing challenge in microbicide trials. Methods: We compared adherence estimates using two applicator tests (a dye stain assay [DSA] and an ultraviolet light assay [UVA]), the Wisebag (an applicator container that electronically tracks container openings), and self-reported adherence (ability, frequency, and percent missed doses). Healthy, HIV-negative, non-pregnant US women aged 23 to 45 received a Wisebag and 32 applicators filled with placebo gel, were instructed to insert one applicator daily for 30 days, returned the Wisebag and all applicators, and completed an exit interview. Emptied applicators were tested by UVA and then DSA, and scored by two blinded readers. Positive and negative controls were randomly included in applicator batches. Results: Among 42 women enrolled, 39 completed the study. DSA and UVA yielded similar sensitivity (97% and 95%) and specificity (79% and 79%). Two participants had fully inoperable Wisebags and nine had partially inoperable Wisebags. The proportion of participants considered to have high adherence (≥80%) varied: 43% (Wisebag), 46% (UVA), 49% (DSA), and 62% to 82% (self-reports). For estimating high adherence, Wisebag had a sensitivity of 76% (95% CI, 50% to 93%) and a specificity of 85% (95% CI, 62% to 97%) compared with DSA. Although 28% of participants reported forgetting to open the Wisebag daily, 59% said it helped them remember gel use. Conclusions: DSA and UVA performed similarly. Compared with these tests, self-reports overestimated and Wisebag underestimated adherence. Although Wisebag may encourage gel use, the applicator tests currently appear more useful for measuring use in clinical trials. PMID:24220357

Acceleration of low-energy ions at parallel shocks with a focused transport model

DOE PAGES

Zuo, Pingbing; Zhang, Ming; Rassoul, Hamid K.

2013-04-10

Here, we present a test particle simulation on the injection and acceleration of low-energy suprathermal particles by parallel shocks with a focused transport model. The focused transport equation contains all necessary physics of shock acceleration, but avoids the limitation of diffusive shock acceleration (DSA) that requires a small pitch angle anisotropy. This simulation verifies that the particles with speeds of a fraction of to a few times the shock speed can indeed be directly injected and accelerated into the DSA regime by parallel shocks. At higher energies starting from a few times the shock speed, the energy spectrum of acceleratedmore » particles is a power law with the same spectral index as the solution of standard DSA theory, although the particles are highly anisotropic in the upstream region. The intensity, however, is different from that predicted by DSA theory, indicating a different level of injection efficiency. It is found that the shock strength, the injection speed, and the intensity of an electric cross-shock potential (CSP) jump can affect the injection efficiency of the low-energy particles. A stronger shock has a higher injection efficiency. In addition, if the speed of injected particles is above a few times the shock speed, the produced power-law spectrum is consistent with the prediction of standard DSA theory in both its intensity and spectrum index with an injection efficiency of 1. CSP can increase the injection efficiency through direct particle reflection back upstream, but it has little effect on the energetic particle acceleration once the speed of injected particles is beyond a few times the shock speed. This test particle simulation proves that the focused transport theory is an extension of DSA theory with the capability of predicting the efficiency of particle injection.« less

Quantitative blood flow measurements in the small animal cardiopulmonary system using digital subtraction angiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin Mingde; Marshall, Craig T.; Qi, Yi

Purpose: The use of preclinical rodent models of disease continues to grow because these models help elucidate pathogenic mechanisms and provide robust test beds for drug development. Among the major anatomic and physiologic indicators of disease progression and genetic or drug modification of responses are measurements of blood vessel caliber and flow. Moreover, cardiopulmonary blood flow is a critical indicator of gas exchange. Current methods of measuring cardiopulmonary blood flow suffer from some or all of the following limitations--they produce relative values, are limited to global measurements, do not provide vasculature visualization, are not able to measure acute changes, aremore » invasive, or require euthanasia. Methods: In this study, high-spatial and high-temporal resolution x-ray digital subtraction angiography (DSA) was used to obtain vasculature visualization, quantitative blood flow in absolute metrics (ml/min instead of arbitrary units or velocity), and relative blood volume dynamics from discrete regions of interest on a pixel-by-pixel basis (100x100 {mu}m{sup 2}). Results: A series of calibrations linked the DSA flow measurements to standard physiological measurement using thermodilution and Fick's method for cardiac output (CO), which in eight anesthetized Fischer-344 rats was found to be 37.0{+-}5.1 ml/min. Phantom experiments were conducted to calibrate the radiographic density to vessel thickness, allowing a link of DSA cardiac output measurements to cardiopulmonary blood flow measurements in discrete regions of interest. The scaling factor linking relative DSA cardiac output measurements to the Fick's absolute measurements was found to be 18.90xCO{sub DSA}=CO{sub Fick}. Conclusions: This calibrated DSA approach allows repeated simultaneous visualization of vasculature and measurement of blood flow dynamics on a regional level in the living rat.« less

3D digital subtraction angiography of intracranial aneurysms: comparison of flat panel detector with conventional image intensifier TV system using a vascular phantom.

PubMed

Kakeda, S; Korogi, Y; Ohnari, N; Hatakeyama, Y; Moriya, J; Oda, N; Nishino, K; Miyamoto, W

2007-05-01

Compared with the image intensifier (I.I.)-TV system, the flat panel detector (FPD) system of direct conversion type has several theoretic advantages, such as higher spatial resolution, wide dynamic range, and no image distortion. The purpose of this study was to compare the image quality of 3D digital subtraction angiography (DSA) in the FPD and conventional I.I.-TV systems using a vascular phantom. An anthropomorphic vascular phantom was designed to simulate the various intracranial aneurysms with aneurysmal bleb. The tubes of this vascular phantom were filled with 2 concentrations of contrast material (300 and 150 mg I/mL), and we obtained 3D DSA using the FPD and I.I.-TV systems. First, 2 blinded radiologists compared the volume-rendering images for 3D DSA on the FPD and I.I.-TV systems, looking for pseudostenosis artifacts. Then, 2 other radiologists independently evaluated both systems for the depiction of the simulated aneurysm and aneurysmal bleb using a 5-point scale. For the degree of the pseudostenosis artifacts at the M1 segment of the middle cerebral artery at 300 mg I/mL, 3D DSA with FPD system showed mild stenoses, whereas severe stenoses were observed at 3D DSA with I.I.-TV system. At both concentrations, the FPD system was significantly superior to I.I.-TV system regarding the depiction of aneurysm and aneurysmal bleb. Compared with the I.I.-TV system, the FPD system could create high-resolution 3D DSA combined with a reduction of the pseudostenosis artifacts.

Effective doses in children: association with common complex imaging techniques used during interventional radiology procedures.

PubMed

Lai, Priscilla; McNeil, Sarah M; Gordon, Christopher L; Connolly, Bairbre L

2014-12-01

The purpose of this study was to determine the range of effective doses associated with imaging techniques used during interventional radiology procedures on children. A pediatric phantom set (1, 5, and 10 years) coupled with high-sensitivity metal oxide semiconductor field effect transistor (MOSFET) dosimeters was used to calculate effective doses. Twenty MOSFETs were inserted into each phantom at radiosensitive organ locations. The phantoms were exposed to mock head, chest, and abdominal interventional radiology procedures performed with different geometries and magnifications. Fluoroscopy, digital subtraction angiography (DSA), and spin angiography were simulated on each phantom. Road mapping was conducted only on the 5-year-old phantom. International Commission on Radiological Protection publication 103 tissue weights were applied to the organ doses recorded with the MOSFETs to determine effective dose. For easy application to clinical cases, doses were normalized per minute of fluoroscopy and per 10 frames of DSA or spin angiography. Effective doses from DSA, angiography, and fluoroscopy were higher for younger ages because of magnification use and were largest for abdominal procedures. DSA of the head, chest, and abdomen (normalized per 10 frames) imparted doses 2-3 times as high as corresponding doses per minute of fluoroscopy while all other factors remained unchanged (age, projection, collimation, magnification). Three to five frames of DSA imparted an effective dose equal to doses from 1 minute of fluoroscopy. Doses from spin angiography were almost one-half the doses received from an equivalent number of frames of DSA. Patient effective doses during interventional procedures vary substantially depending on procedure type but tend to be higher because of magnification use in younger children and higher in the abdomen.

Many de novo donor‐specific antibodies recognize β2‐microglobulin‐free, but not intact HLA heterodimers

PubMed Central

Michel, K.; Santella, R.; Steers, J.; Sahajpal, A.; Downey, F. X.; Thohan, V.

2016-01-01

Abstract Solid‐phase single antigen bead (SAB) assays are standard of care for detection and identification of donor‐specific antibody (DSA) in patients who receive solid organ transplantation (SOT). While several studies have documented the reproducibility and sensitivity of SAB testing for DSA, there are little data available concerning its specificity. This study describes the identification of antibodies to β2‐microglobulin‐free human leukocyte antigen (β2‐m‐fHLA) heavy chains on SAB arrays and provides a reassessment of the clinical relevance of DSA testing by this platform. Post‐transplant sera from 55 patients who were positive for de novo donor‐specific antibodies on a SAB solid‐phase immunoassay were tested under denaturing conditions in order to identify antibodies reactive with β2‐m‐fHLA or native HLA (nHLA). Antibodies to β2‐m‐fHLA were present in nearly half of patients being monitored in the post‐transplant period. The frequency of antibodies to β2‐m‐fHLA was similar among DSA and HLA antigens that were irrelevant to the transplant (non‐DSA). Among the seven patients with clinical or pathologic antibody‐mediated rejection (AMR), none had antibodies to β2‐m‐fHLA exclusively; thus, the clinical relevance of β2‐m‐fHLA is unclear. Our data suggests that SAB testing produces false positive reactions due to the presence of β2‐m‐fHLA and these can lead to inappropriate assignment of unacceptable antigens during transplant listing and possibly inaccurate identification of DSA in the post‐transplant period. PMID:27060279

Novel integrated electrodialysis/electro-oxidation process for the efficient degradation of 2,4-dichlorophenoxyacetic acid.

PubMed

Raschitor, A; Llanos, J; Cañizares, P; Rodrigo, M A

2017-09-01

This work presents a novel approach of wastewater treatment technology that consists of a combined electrodialysis/electro-oxidation process, specially designed to allow increasing the efficiency in the oxidation of ionic organic pollutants contained in diluted waste. Respect to conventional electrolysis, the pollutant is simultaneously concentrated and oxidized, enhancing the performance of the cell due to the higher concentration achieved in the nearness of the anode. A proof of concept is tested with the ionic pesticide 2,4-D (2,4-dichlorophenoxyacetic acid) and results show that the efficiency of this new technology overcomes that electrolysis by more than double, regardless the supporting electrolyte used (either NaCl or Na 2 SO 4 ). Moreover, the removal rate of 2,4-D when using NaCl was found to be more efficient, due to the best performance of the electrode material selected (DSA ® ) towards the formation of oxidants in chloride supporting electrolyte. These results open the way for overcoming the efficiency limitations of electrochemical treatment processes for the treatment of solutions with low concentrated ionic pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Binders and Hosts for High-Capacity Lithium-ion Battery Anodes

NASA Astrophysics Data System (ADS)

Dufficy, Martin Kyle

Lithium-ion batteries (LIBs) are universal electrochemical energy storage devices that have revolutionized our mobile society. Nonetheless, societal and technological advances drive consumer demand for LIBs with enhanced electrochemical performance, such as higher charge capacity and longer life, compared to conventional LIBs. One method to enhance LIB performance is to replace graphite, the industry standard anode since commercialization of LIBs in 1991, with high-charge capacity materials. Implementing high-capacity anode materials such as tin, silicon, and manganese vanadates, to LIBs presents challenges; Li-insertion is destructive to anode framework, and increasing capacity increases structural strains that pulverize anode materials and results in a short-cycle life. This thesis reports on various methods to extended the cycle life of high-capacity materials. Most of the work is conducted on nano-sized anode materials to reduce Li and electron transport pathway length (facilitating charge-transfer) and reduce strains from volume expansions (preserving anode structure). The first method involves encapsulating tin particles into a graphene-containing carbon nanofiber (CNF) matrix. The composite-CNF matrix houses tin particles to assume strains from tin-volume expansions and produces favorable surface-electrolyte chemistries for stable charge-discharge cycling. Before tin addition, graphene-containing CNFs are produced and assessed as anode materials for LIBs. Graphene addition to CNFs improves electronic and mechanical properties of CNFs. Furthermore, the 2-D nature of graphene provides Li-binding sites to enhance composite-CNF both first-cycle and high-rate capacities > 150% when compared to CNFs in the absence of graphene. With addition of Sn, we vary loadings and thermal production temperature to elucidate structure-composition relationships of tin and graphene-containing CNF electrodes that lead to increased capacity retention. Of note, electrodes containing ≤ 20 wt% tin result in small tin (metallic and tin oxide) particles (≤ 15 nm) within the composite-CNF matrix, which yield long cycle-lives; large reversible capacities of ˜ 600 mAh g-1 are observed at 0.2-C rates, while capacities of ˜ 400 mAh g-1 (double the capacity of CNFs) are observed after hundreds of cycles at 2-C rates. The second method comprises an approach to enhance the cycle life of silicon anodes. Many researchers believe that Si is the future anode material of LIBs, and Si is capable of providing a much needed boost in overall cell performance. Silicon has the highest known charge capacity at ˜ 3579 mAh g-1, nearly an order of magnitude larger than graphite (372 mAh g-1). In attempt to realize the entire capacity of Si anodes, we use binding agents to prolong cycle life. Binding agents enhance capacity retention via favorable interactions with cell components such as active materials and electrolytes. In this study, we introduce galactomannans (specifically, guar) as viable, inexpensive, biopolymer binders for Si electrodes. In attempt to elucidate the role of the binder in Si electrodes, we study guar-electrode and -electrolyte interactions that lead to electrochemical performance enhancements. We recognize that there are deficiencies in guar-silicon systems, which we address in our following approach. Notably, we develop a guar-derived binder to increase the strength and conductivity of Si-based electrodes by crosslinking guar and carbon black dispersions. The crosslinked binders, in effect, enhance electrode adhesion and hinder electrode cracking by self-healing. This study monitors gelation via rheological methods and assesses effects of crosslinking density on physical and electrochemical properties. Lastly, we consider a vacancy-induced manganese vanadate as high-capacity, high-power anodes for LIBs. Rather than assessing nanoparticles, we tailored molecular structure to enhance electrochemical performances. X-ray diffraction studies enable us to suggest a Li-insertion mechanism, where Li travels through large channels created by defects in the crystal structure. The ensuing manganese vanadate structure produces a stable framework that results in stable cycling of hundreds of cycles.

Core–Shell Nanoparticle Coating as an Interfacial Layer for Dendrite-Free Lithium Metal Anodes

DOE PAGES

Liu, Wei; Li, Weiyang; Zhuo, Denys; ...

2017-02-08

Lithium metal based batteries represent a major challenge and opportunity in enabling a variety of devices requiring high-energy-density storage. However, dendritic lithium growth has limited the practical application of lithium metal anodes. Here we report a nanoporous, flexible and electrochemically stable coating of silica@poly(methyl methacrylate) (SiO 2@PMMA) core–shell nanospheres as an interfacial layer on lithium metal anode. This interfacial layer is capable of inhibiting Li dendrite growth while sustaining ionic flux through it, which is attributed to the nanoscaled pores formed among the nanospheres. Lastly, enhanced Coulombic efficiencies during lithium charge/discharge cycles have been achieved at various current densities andmore » areal capacities.« less

Core–Shell Nanoparticle Coating as an Interfacial Layer for Dendrite-Free Lithium Metal Anodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wei; Li, Weiyang; Zhuo, Denys

Lithium metal based batteries represent a major challenge and opportunity in enabling a variety of devices requiring high-energy-density storage. However, dendritic lithium growth has limited the practical application of lithium metal anodes. Here we report a nanoporous, flexible and electrochemically stable coating of silica@poly(methyl methacrylate) (SiO 2@PMMA) core–shell nanospheres as an interfacial layer on lithium metal anode. This interfacial layer is capable of inhibiting Li dendrite growth while sustaining ionic flux through it, which is attributed to the nanoscaled pores formed among the nanospheres. Lastly, enhanced Coulombic efficiencies during lithium charge/discharge cycles have been achieved at various current densities andmore » areal capacities.« less

Enhancing cycling durability of Li-ion batteries with hierarchical structured silicon-graphene hybrid anodes.

PubMed

Loveridge, Melanie J; Lain, Michael J; Huang, Qianye; Wan, Chaoying; Roberts, Alexander J; Pappas, George S; Bhagat, Rohit

2016-11-09

Hybrid anode materials consisting of micro-sized silicon (Si) particles interconnected with few-layer graphene (FLG) nanoplatelets and sodium-neutralized poly(acrylic acid) as a binder were evaluated for Li-ion batteries. The hybrid film has demonstrated a reversible discharge capacity of ∼1800 mA h g -1 with a capacity retention of 97% after 200 cycles. The superior electrochemical properties of the hybrid anodes are attributed to a durable, hierarchical conductive network formed between Si particles and the multi-scale carbon additives, with enhanced cohesion by the functional polymer binder. Furthermore, improved solid electrolyte interphase (SEI) stability is achieved from the electrolyte additives, due to the formation of a kinetically stable film on the surface of the Si.

Current collection by high voltage anodes in near ionospheric conditions

NASA Technical Reports Server (NTRS)

Antoniades, John A.; Greaves, Rod G.; Boyd, D. A.; Ellis, R.

1990-01-01

The authors experimentally identified three distinct regimes with large differences in current collection in the presence of neutrals and weak magnetic fields. In magnetic field/anode voltage space the three regions are separated by very sharp transition boundaries. The authors performed a series of laboratory experiments to study the dependence of the region boundaries on several parameters, such as the ambient neutral density, plasma density, magnetic field strength, applied anode voltage, voltage pulsewidth, chamber material, chamber size and anode radius. The three observed regimes are: classical magnetic field limited collection; stable medium current toroidal discharge; and large scale, high current space glow discharge. There is as much as several orders of magnitude of difference in the amount of collected current upon any boundary crossing, particularly if one enters the space glow regime. They measured some of the properties of the plasma generated by the breakdown that is present in regimes II and III in the vicinity of the anode including the sheath modified electrostatic potential, I-V characteristics at high voltage as well as the local plasma density.

Dual Function Behavior of Carbon Fiber-Reinforced Polymer in Simulated Pore Solution.

PubMed

Zhu, Ji-Hua; Guo, Guanping; Wei, Liangliang; Zhu, Miaochang; Chen, Xianchuan

2016-02-06

The mechanical and electrochemical performance of carbon fiber-reinforced polymer (CFRP) were investigated regarding a novel improvement in the load-carrying capacity and durability of reinforced concrete structures by adopting CFRP as both a structural strengthener and an anode of the impressed current cathodic protection (ICCP) system. The mechanical and anode performance of CFRP were investigated in an aqueous pore solution in which the electrolytes were available to the anode in a cured concrete structure. Accelerated polarization tests were designed with different test durations and various levels of applied currents in accordance with the international standard. The CFRP specimens were mechanically characterized after polarization. The measured feeding voltage and potential during the test period indicates CFRP have stable anode performance in a simulated pore solution. Two failure modes were observed through tensile testing. The tensile properties of the post-polarization CFRP specimens declined with an increased charge density. The CFRP demonstrated success as a structural strengthener and ICCP anode. We propose a mathematic model predicting the tensile strengths of CFRP with varied impressed charge densities.

Dual Function Behavior of Carbon Fiber-Reinforced Polymer in Simulated Pore Solution

PubMed Central

Zhu, Ji-Hua; Guo, Guanping; Wei, Liangliang; Zhu, Miaochang; Chen, Xianchuan

2016-01-01

The mechanical and electrochemical performance of carbon fiber-reinforced polymer (CFRP) were investigated regarding a novel improvement in the load-carrying capacity and durability of reinforced concrete structures by adopting CFRP as both a structural strengthener and an anode of the impressed current cathodic protection (ICCP) system. The mechanical and anode performance of CFRP were investigated in an aqueous pore solution in which the electrolytes were available to the anode in a cured concrete structure. Accelerated polarization tests were designed with different test durations and various levels of applied currents in accordance with the international standard. The CFRP specimens were mechanically characterized after polarization. The measured feeding voltage and potential during the test period indicates CFRP have stable anode performance in a simulated pore solution. Two failure modes were observed through tensile testing. The tensile properties of the post-polarization CFRP specimens declined with an increased charge density. The CFRP demonstrated success as a structural strengthener and ICCP anode. We propose a mathematic model predicting the tensile strengths of CFRP with varied impressed charge densities. PMID:28787900

Thin film integrated capacitors with sputtered-anodized niobium pentoxide dielectric for decoupling applications

NASA Astrophysics Data System (ADS)

Jacob, Susan

Electronics system miniaturization is a major driver for high-k materials. High-k materials in capacitors allow for high capacitance, enabling system miniaturization. Ta2O5 (k˜24) has been the dominant high-k material in the electronic industry for decoupling capacitors, filter capacitors, etc. In order to facilitate further system miniaturization, this project has investigated thin film integrated capacitors with Nb2O5 dielectric. Nb2O 5 has k˜41 and is a potential candidate for replacing Ta2O5. But, the presence of suboxides (NbO2 and NbO) in the dielectric deteriorates the electrical properties (leakage current, thermal instability of capacitance, etc.). Also, the high oxygen solubility of niobium results in oxygen diffusion from the dielectric to niobium metal, if any is present. The major purpose of this project was to check the ability of NbN as a diffusion barrier and fabricate thermally stable niobium capacitors. As a first step to produce niobium capacitors, the material characterizations of reactively sputtered Nb2O5 and NbN were done. Thickness and film composition, and crystal structures of the sputtered films were obtained and the deposition parameters for the desired stoichiometry were found. Also, anodized Nb2O5 was characterized for its stoichiometry and thickness. To study the effect of nitrides on capacitance and thermal stability, Ta2O5 capacitors were initially fabricated with and without TaN. The results showed that the nitride does not affect the capacitance, and that capacitors with TaN are stable up to 150°C. In the next step, niobium capacitors were first fabricated with anodized dielectric and the oxygen diffusion issues associated with capacitor processing were studied. Reactively sputtered Nb2O5 was anodized to form complete Nb2O5 (with few oxygen vacancies) and NbN was used to sandwich the dielectric. The capacitor fabrication was not successful due to the difficulties in anodizing the sputtered dielectric. Another method, anodizing reactively sputtered Nb2O5 and a thin layer of sputtered niobium metal yielded high yield (99%) capacitors. Capacitors were fabricated with and without NbN and the results showed 93% decrease in leakage for a capacitor with ˜2000 A dielectric when NbN was present in the structure. These capacitors could withstand 20 V and showed 2.7 muA leakage current at 5 V. These results were obtained after thermal storage at 100°C and 150°C in air for 168 hours at each temperature. Two set of experiments were performed using Ta2O5 dielectric: one to determine the effect of anodization end point on the thickness (capacitance) and the second to determine the effect of boiling the dielectric on functional yield. The anodization end point experiment showed that the final current of anodization along with the anodizing voltage determines the anodic oxide thickness. The lower the current, the thicker the films produced by anodization. Therefore, it was important to specify the final current along with the anodization voltage for oxide growth rate. The capacitors formed with boiled wafers showed better functional yield 3 out of 5 times compared with the unboiled wafer. Niobium anodization was studied for the Nb--->Nb 2O5 conversion ratio and the effect of anodization bath temperature on the oxide film; a color chart was prepared for thicknesses ranging from 1900 A - 5000 A. The niobium metal to oxide conversion ratio was found to change with temperature.

Composite lithium metal anode by melt infusion of lithium into a 3D conducting scaffold with lithiophilic coating.

PubMed

Liang, Zheng; Lin, Dingchang; Zhao, Jie; Lu, Zhenda; Liu, Yayuan; Liu, Chong; Lu, Yingying; Wang, Haotian; Yan, Kai; Tao, Xinyong; Cui, Yi

2016-03-15

Lithium metal-based battery is considered one of the best energy storage systems due to its high theoretical capacity and lowest anode potential of all. However, dendritic growth and virtually relative infinity volume change during long-term cycling often lead to severe safety hazards and catastrophic failure. Here, a stable lithium-scaffold composite electrode is developed by lithium melt infusion into a 3D porous carbon matrix with "lithiophilic" coating. Lithium is uniformly entrapped on the matrix surface and in the 3D structure. The resulting composite electrode possesses a high conductive surface area and excellent structural stability upon galvanostatic cycling. We showed stable cycling of this composite electrode with small Li plating/stripping overpotential (<90 mV) at a high current density of 3 mA/cm(2) over 80 cycles.

Absence of dynamic strain aging in an additively manufactured nickel-base superalloy.

PubMed

Beese, Allison M; Wang, Zhuqing; Stoica, Alexandru D; Ma, Dong

2018-05-25

Dynamic strain aging (DSA), observed macroscopically as serrated plastic flow, has long been seen in nickel-base superalloys when plastically deformed at elevated temperatures. Here we report the absence of DSA in Inconel 625 made by additive manufacturing (AM) at temperatures and strain rates where DSA is present in its conventionally processed counterpart. This absence is attributed to the unique AM microstructure of finely dispersed secondary phases (carbides, N-rich phases, and Laves phase) and textured grains. Based on experimental observations, we propose a dislocation-arrest model to elucidate the criterion for DSA to occur or to be absent as a competition between dislocation pipe diffusion and carbide-carbon reactions. With in situ neutron diffraction studies of lattice strain evolution, our findings provide a new perspective for mesoscale understanding of dislocation-solute interactions and their impact on work-hardening behaviors in high-temperature alloys, and have important implications for tailoring thermomechanical properties by microstructure control via AM.

Highly Stable Operation of Lithium Metal Batteries Enabled by the Formation of a Transient High Concentration Electrolyte Layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jianming; Yan, Pengfei; Mei, Donghai

2016-02-08

Lithium (Li) metal has been extensively investigated as an anode for rechargeable battery applications due to its ultrahigh specific capacity and the lowest redox potential. However, significant challenges including dendrite growth and low Coulombic efficiency are still hindering the practical applications of rechargeable Li metal batteries. Here, we demonstrate that long-term cycling of Li metal batteries can be realized by the formation of a transient high concentration electrolyte layer near the surface of Li metal anode during high rate discharge process. The highly concentrated Li+ ions in this transient layer will immediately solvate with the available solvent molecules and facilitatemore » the formation of a stable and flexible SEI layer composed of a poly(ethylene carbonate) framework integrated with other organic/inorganic lithium salts. This SEI layer largely suppresses the corrosion of Li metal anode by free organic solvents and enables the long-term operation of Li metal batteries. The fundamental findings in this work provide a new direction for the development and operation of Li metal batteries that could be operated at high current densities for a wide range of applications.« less

Alkaline anion exchange membrane water electrolysis: Effects of electrolyte feed method and electrode binder content

NASA Astrophysics Data System (ADS)

Cho, Min Kyung; Park, Hee-Young; Lee, Hye Jin; Kim, Hyoung-Juhn; Lim, Ahyoun; Henkensmeier, Dirk; Yoo, Sung Jong; Kim, Jin Young; Lee, So Young; Park, Hyun S.; Jang, Jong Hyun

2018-04-01

Herein, we investigate the effects of catholyte feed method and anode binder content on the characteristics of anion exchange membrane water electrolysis (AEMWE) to construct a high-performance electrolyzer, revealing that the initial AEMWE performance is significantly improved by pre-feeding 0.5 M aqueous KOH to the cathode. The highest long-term activity during repeated voltage cycling is observed for AEMWE operation in the dry cathode mode, for which the best long-term performance among membrane electrode assemblies (MEAs) featuring polytetrafluoroethylene (PTFE) binder-impregnated (5-20 wt%) anodes is detected for a PTFE content of 20 wt%. MEAs with low PTFE content (5 and 9 wt%) demonstrate high initial performance, rapid performance decay, and significant catalyst loss from the electrode during long-term operation, whereas the MEA with 20 wt% PTFE allows stable water electrolysis for over 1600 voltage cycles. Optimization of cell operating conditions (i.e., operation in dry cathode mode at an optimum anode binder content following an initial solution feed) achieves an enhanced water splitting current density (1.07 A cm-2 at 1.8 V) and stable long-term AEMWE performance (0.01% current density reduction per voltage cycle).

High performance sulfur graphite full cell for next generation sulfur Li-ion battery

NASA Astrophysics Data System (ADS)

Wu, Yunwen; Momma, Toshiyuki; Yokoshima, Tokihiko; Nara, Hiroki; Osaka, Tetsuya

2018-06-01

Sulfur (S) Li-ion battery which use the metallic Li free anode is deemed as a promising solution to conquer the hazards originating from Li metal. However, stable cycling performance and low production price of the S Li-ion battery still remain challenging. Here, we propose a S-LixC full cell system by paring a S cathode and a pre-lithiated graphite anode which is cheap and commercially available. It shows stable cycling performance with a capacity around 1300 mAh (g-S)-1 at 0.2 C-rate and 1000 mAh (g-S)-1 at 0.5 C-rate. In addition, 0.1% per cycle capacity fading rate with a capacity retention of 880 mAh (g-S)-1 after 400 cycles at 0.2 C-rate has been achieved. The pre-formed solid electrolyte interphase (SEI) layer on the pre-lithaited graphite anode largely contributes to the high capacity performance. Notably, a 10-times-enlarged scale of S-LixC laminate type full cell has been assembled with high capacity performance (around 1000 mAh (g-S)-1) even after high rate cycling.

Large and stable reversible lithium-ion storages from mesoporous SnO2 nanosheets with ultralong lifespan over 1000 cycles

NASA Astrophysics Data System (ADS)

Zhang, Xiao; Jiang, Bin; Guo, Jinxue; Xie, Yaping; Tang, Lin

2014-12-01

The major challenge to promote the commercialization of SnO2 anode materials is to construct unique structures and/or composites that could alleviate the volume effect and extend the lifespan. This study develops an efficient synthetic solution for the preparation of mesoporous SnO2 nanosheets, which involves an evaporation-induced selfassembly process and the following thermal treatment. Surfactant F127 is used as the soft template to form abundant cores. The as-prepared sample intrinsically inherits flexible sheet-like structure and porous features, as characterized with XRD, SEM, TEM and BET techniques. Based on these combining structural benefits, the sample is utilized as anode materials for lithium-ion batteries and exhibits excellent Li+ storage performance such as large and stable reversible capacity, good rate capability, and especially the outstanding durable cycling life of over 1000 cycles, which meets the demands of practical applications. The structural changes of SnO2 nanosheets are observed from the decomposed electrodes after different electrochemical cycles. Moreover, this synthesis strategy may offer an alternative and universal approach for synthesis of other transitional metal oxides or their binary composites as high-performance anode materials for lithium-ion batteries.

TU-H-CAMPUS-IeP1-04: Combined Organ Dose for Digital Subtraction Angiography and Computed Tomography Using Monte Carlo Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakabe, D; Ohno, T; Araki, F

Purpose: The purpose of this study was to evaluate the combined organ dose of digital subtraction angiography (DSA) and computed tomography (CT) using a Monte Carlo (MC) simulation on the abdominal intervention. Methods: The organ doses for DSA and CT were obtained with MC simulation and actual measurements using fluorescent-glass dosimeters at 7 abdominal portions in an Alderson-Rando phantom. DSA was performed from three directions: posterior anterior (PA), right anterior oblique (RAO), and left anterior oblique (LAO). The organ dose with MC simulation was compared with actual radiation dose measurements. Calculations for the MC simulation were carried out with themore » GMctdospp (IMPS, Germany) software based on the EGSnrc MC code. Finally, the combined organ dose for DSA and CT was calculated from the MC simulation using the X-ray conditions of a patient with a diagnosis of hepatocellular carcinoma. Results: For DSA from the PA direction, the organ doses for the actual measurements and MC simulation were 2.2 and 2.4 mGy/100 mAs at the liver, respectively, and 3.0 and 3.1 mGy/100 mAs at the spinal cord, while for CT, the organ doses were 15.2 and 15.1 mGy/100 mAs at the liver, and 14.6 and 13.5 mGy/100 mAs at the spinal cord. The maximum difference in organ dose between the actual measurements and the MC simulation was 11.0% of the spleen at PA, 8.2% of the spinal cord at RAO, and 6.1% of left kidney at LAO with DSA and 9.3% of the stomach with CT. The combined organ dose (4 DSAs and 6 CT scans) with the use of actual patient conditions was found to be 197.4 mGy for the liver and 205.1 mGy for the spinal cord. Conclusion: Our method makes it possible to accurately assess the organ dose to patients for abdominal intervention with combined DSA and CT.« less

Quantitative flow and velocity measurements of pulsatile blood flow with 4D-DSA

NASA Astrophysics Data System (ADS)

Shaughnessy, Gabe; Hoffman, Carson; Schafer, Sebastian; Mistretta, Charles A.; Strother, Charles M.

2017-03-01

Time resolved 3D angiographic data from 4D DSA provides a unique environment to explore physical properties of blood flow. Utilizing the pulsatility of the contrast waveform, the Fourier components can be used to track the waveform motion through vessels. Areas of strong pulsatility are determined through the FFT power spectrum. Using this method, we find an accuracy from 4D-DSA flow measurements within 7.6% and 6.8% RMSE of ICA PCVIPR and phantom flow probe validation measurements, respectively. The availability of velocity and flow information with fast acquisition could provide a more quantitative approach to treatment planning and evaluation in interventional radiology.

Yolk-shell structured Sb@C anodes for high energy Na-ion batteries

DOE PAGES

Song, Junhua; Yan, Pengfei; Luo, Langli; ...

2017-09-04

Despite great advances in sodium-ion battery developments, the search for high energy and stable anode materials remains a challenge. Alloy or conversion-typed anode materials are attractive candidates of high specific capacity and low voltage potential, yet their applications are hampered by the large volume expansion and hence poor electrochemical reversibility and fast capacity fade. Here in this paper, we use antimony (Sb) as an example to demonstrate the use of yolk-shell structured anodes for high energy Na-ion batteries. The Sb@C yolk-shell structure prepared by controlled reduction and selective removal of Sb 2O 3 from carbon coated Sb 2O 3 nanoparticlesmore » can accommodate the Sb swelling upon sodiation and improve the structural/electrical integrity against pulverization. It delivers a high specific capacity of ~ 554 mAh g -1, good rate capability (315 mhA g-1 at 10 C rate) and long cyclability (92% capacity retention over 200 cycles). Full-cells of O3-Na 0.9[Cu0.22Fe 0.30Mn 0.48]O 2 cathodes and Sb@C-hard carbon composite anodes demonstrate a high specific energy of ~ 130 Wh kg-1 (based on the total mass of cathode and anode) in the voltage range of 2.0–4.0 V, ~ 1.5 times energy of full-cells with similar design using hard carbon anodes.« less

Yolk-shell structured Sb@C anodes for high energy Na-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Junhua; Yan, Pengfei; Luo, Langli

Despite great advances in sodium-ion battery developments, the search for high energy and stable anode materials remains a challenge. Alloy or conversion-typed anode materials are attractive candidates of high specific capacity and low voltage potential, yet their applications are hampered by the large volume expansion and hence poor electrochemical reversibility and fast capacity fade. Here, we use antimony (Sb) as an example to demonstrate the use of yolk-shell structured anodes for high energy Na-ion batteries. The Sb@C yolk-shell structure prepared by controlled reduction and selective removal of Sb2O3 from carbon coated Sb2O3 nanoparticles can accommodate the Sb swelling upon sodiationmore » and improve the structural/electrical integrity against pulverization. It delivers a high specific capacity of ~554 mAh•g-1, good rate capability (315 mhA•g-1 at 10C rate) and long cyclability (92% capacity retention over 200 cycles). Full-cells of O3-Na0.9[Cu0.22Fe0.30Mn0.48]O2 cathodes and Sb@C-hard carbon composite anodes demonstrate a high specific energy of ~130 Wh•kg-1 (based on the total mass of cathode and anode) in the voltage range of 2.0-4.0 V, ~1.5 times energy of full-cells with similar design using hard carbon anodes.« less

Yolk-shell structured Sb@C anodes for high energy Na-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Junhua; Yan, Pengfei; Luo, Langli

Despite great advances in sodium-ion battery developments, the search for high energy and stable anode materials remains a challenge. Alloy or conversion-typed anode materials are attractive candidates of high specific capacity and low voltage potential, yet their applications are hampered by the large volume expansion and hence poor electrochemical reversibility and fast capacity fade. Here in this paper, we use antimony (Sb) as an example to demonstrate the use of yolk-shell structured anodes for high energy Na-ion batteries. The Sb@C yolk-shell structure prepared by controlled reduction and selective removal of Sb 2O 3 from carbon coated Sb 2O 3 nanoparticlesmore » can accommodate the Sb swelling upon sodiation and improve the structural/electrical integrity against pulverization. It delivers a high specific capacity of ~ 554 mAh g -1, good rate capability (315 mhA g-1 at 10 C rate) and long cyclability (92% capacity retention over 200 cycles). Full-cells of O3-Na 0.9[Cu0.22Fe 0.30Mn 0.48]O 2 cathodes and Sb@C-hard carbon composite anodes demonstrate a high specific energy of ~ 130 Wh kg-1 (based on the total mass of cathode and anode) in the voltage range of 2.0–4.0 V, ~ 1.5 times energy of full-cells with similar design using hard carbon anodes.« less

A new binder-free and conductive-additive-free TiO2/WO3-W integrative anode material produced by laser ablation

NASA Astrophysics Data System (ADS)

Su, Yibo; Zhang, Hongjun; Liang, Peng; Liu, Kai; Cai, Mingyong; Huang, Zeya; Wang, Chang-An; Zhong, Minlin

2018-02-01

Although transition metal oxides anodes have attracted lots of attention, there are still many problems to be resolved. Complicated fabrication process, high cost and poor electrochemical performances are the most important ones, together hindering transition metal oxides anodes for practical use. Herein, we provide a new approach to fabricate a binder-free and conductive-additive-free TiO2/WO3-W integrative anode material through the nanosecond laser ablation and dip-coating technology, which simplifies the entire anode preparation process with no need for a conventional tape-casting procedure. Using this method, great time cost, machine cost and labor cost related to mixing and tape-casting process can be saved on the basis of good electrochemical performances. The prepared TiO2/WO3-W integrative anode realizes a first Coulombic efficiency of 75.6% and attains to a stable capacity within the first five cycles. It can still maintain a capacity of 600 mAh g-1 in the range of 0.01-3 V vs. Li+/Li at a current rate of 0.2 C after 500 cycles. This work offers a new way to achieve a fast fabrication of the integrative anode for lithium ion battery, which is universal for other transition metals (such as Fe, Cu, Ni, Co, Mo, W etc.).

Combining a Disturbance Observer with Triple-Loop Control Based on MEMS Accelerometers for Line-of-Sight Stabilization

PubMed Central

Huang, Yongmei; Deng, Chao; Ren, Wei; Wu, Qiongyan

2017-01-01

In the CCD-based fine tracking optical system (FTOS), the whole disturbance suppression ability (DSA) is the product of the inner loop and outer position loop. Traditionally, high sampling fiber-optic gyroscopes (FOGs) are added to the platform to stabilize the line-of-sight (LOS). However, because of the FOGs’ high cost and relatively big volume relative to the back narrow space of small rotating mirrors, we attempt in this work to utilize a cheaper and smaller micro-electro-mechanical system (MEMS) accelerometer to build the inner loop, replacing the FOG. Unfortunately, since accelerometers are susceptible to the low-frequency noise, according to the classical way of using accelerometers, the crucial low-frequency DSA of the system is insufficient. To solve this problem, in this paper, we propose an approach based on MEMS accelerometers combining disturbance observer (DOB) with triple-loop control (TLC) in which the composite velocity loop is built by acceleration integration and corrected by CCD. The DOB is firstly used to reform the platform, greatly improving the medium-frequency DSA. Then the composite velocity loop exchanges a part of medium-frequency performance for the low-frequency DSA. A detailed analysis and experiments verify the proposed method has a better DSA than the traditional way and could totally substitute FOG in the LOS stabilization. PMID:29149050

Quadriplegia caused by an epidural abscess occurring at the same level of cervical destructive spondyloarthropathy: a case report.

PubMed

Lee, Jun-Seok; Ryu, Ji-Hyun; Park, Jong-Tae; Kim, Ki-Won

2017-01-10

Destructive spondyloarthropathy (DSA) is one of the major complications in patients undergoing long-term hemodialysis. To the best of our knowledge, an epidural abscess occurring at the level of preexisting cervical DSA has not been well described in the literature. We report a unique case of quadriplegia caused by an epidural abscess occurring at the same level of preexisting cervical DSA. A 49-year-old woman was transferred to our emergency department with 5 days of sepsis, drowsy mental status, and quadriplegia below the C5 level. The patient had a medical history of hemodialysis for 10 years. Magnetic resonance imaging showed spinal cord compression by an epidural abscess at the level of preexisting cervical DSA. Blood culture revealed methicillin-sensitive Staphylococcus aureus. Infection of the arteriovenous (AV) shunt was considered as the primary focus of sepsis and pyogenic spondylitis. We performed an emergent open door laminoplasty and the vascular team debrided the infected AV shunt site. Approximately 8 months after surgery, the patient was able to perform activities of daily living somewhat independently. Emergent surgical decompression and intensive medical care led to successful recovery from a septic and quadriplegic state in this patient. When diagnosing a patient who has undergone long-term hemodialysis presenting with neurologic deficits, the possibility of infectious spondylitis at the same level as DSA should be considered.

Outcome after Desensitization in HLA or ABO-Incompatible Kidney Transplant Recipients: A Single Center Experience.

PubMed

Kauke, Teresa; Klimaschewski, Sandra; Schoenermarck, Ulf; Fischereder, Michael; Dick, Andrea; Guba, Markus; Stangl, Manfred; Werner, Jens; Meiser, Bruno; Habicht, Antje

2016-01-01

The shortage of deceased donors led to an increase of living donor kidney (LDK) transplantations performed in the presence of donor-specific antibodies (DSA) or ABO incompatibility (ABOi) using various desensitization protocols. We herein analyzed 26 ABOi and 8 Luminex positive DSA patients who were successfully desensitized by anti-CD20, antigen-specific immunoadsorption and/or plasmapheresis to receive an LDK transplant. Twenty LDK recipients with non-donor-specific HLA-antibodies (low risk) and 32 without anti-HLA antibodies (no risk) served as control groups. 1-year graft survival rate and renal function was similar in all 4 groups (creatinine: 1.63 ± 0.5 vs 1.78 ± 0.6 vs 1.64 ± 0.5 vs 1.6 ± 0.3 mg/dl in ABOi, DSA, low risk and no risk group). The incidence of acute T-cell mediated rejections did not differ between the 4 groups (15% vs 12, 5% vs 15% vs 22% in ABOi, DSA, low risk and no risk), while antibody-mediated rejections were only found in the DSA (25%) and ABOi (7.5%) groups. Incidence of BK nephropathy (BKVN) was significantly more frequent after desensitization as compared to controls (5/34 vs 0/52, p = 0.03). We demonstrate favorable short-term allograft outcome in LDK transplant recipients after desensitization. However, the desensitization was associated with an increased risk of BKVN.

Cost identification of abdominal aortic aneurysm imaging by using time and motion analyses.

PubMed

Rubin, G D; Armerding, M D; Dake, M D; Napel, S

2000-04-01

To compare the costs of performing helical computed tomographic (CT) angiography with three-dimensional rendering versus intraarterial digital subtraction angiography (DSA) for preoperative imaging of abdominal aortic aneurysms (AAAs). A single observer determined the variable direct costs of performing nine intraarterial DSA and 10 CT angiographic examinations in age- and general health-matched patients with AAA by using time and motion analyses. All personnel directly involved in the cases were tracked, and the involvement times were recorded to the nearest minute. All material items used during the procedures were recorded. The cost of labor was determined from personnel reimbursement data, and the cost of materials, from vendor pricing. The variable direct costs of laboratory tests and using the ambulatory treatment unit for postprocedural monitoring, as well as all fixed direct costs, were assessed from hospital accounting records. The total costs were determined for each procedure and compared by using the Student t test and calculating the CIs. The mean total direct cost of intraarterial DSA (+/- SD) was $1,052 +/- 71, and that of CT angiography was $300 +/- 30, which are significantly different (P < 4.1 x 10(-11)). With 95% confidence, intraarterial DSA cost 3.2-3.7 times more than CT angiography for the assessment of AAA. Assuming equal diagnostic utility and procedure-related morbidity, institutions may have substantial cost savings whenever CT angiography can replace intraarterial DSA for imaging AAAs.

Follow-up of intracranial aneurysms treated by a WEB flow disrupter: a comparative study of DSA and contrast-enhanced MR angiography.

PubMed

Mine, Benjamin; Tancredi, Illario; Aljishi, Ali; Alghamdi, Faisal; Beltran, Margarita; Herchuelz, Maxime; Lubicz, Boris

2016-06-01

To compare contrast-enhanced MR angiography (CE-MRA) and DSA for the follow-up of intracranial aneurysms (IAs) treated with the Woven EndoBridge embolization system DL (WEB DL; Sequent Medical, Aliso Viejo, California, USA). We retrospectively identified all patients treated with a WEB DL between November 2010 and February 2013 in 2 hospitals. The IA occlusion was graded on follow-up CE-MRA and DSA by 4 independent readers and by 2 readers reaching a consensus, respectively. Interobserver agreement for MRA and intertechnique agreement was evaluated by calculating linear weighted κ. Fifteen patients with 16 IAs were included. Mean delay between MRA and DSA was 2 months (range 0-16 months). Interobserver agreement for MRA was substantial to almost perfect (κ=0.686-0.921; mean κ=0.809). Intertechnique agreement was moderate to substantial (κ=0.579-0.724; mean κ=0.669). Only three out of five inadequately occluded IAs were detected by MRA. CE-MRA is a useful tool for the follow-up of IAs treated with a WEB DL. However, early follow-up with DSA remains mandatory to detect inadequately occluded IAs. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Metal-supported solid oxide fuel cells operated in direct-flame configuration

DOE PAGES

Tucker, Michael C.; Ying, Andrew S.

2017-08-19

Metal-supported solid oxide fuel cells (MS-SOFC) with infiltrated catalysts on both anode and cathode side are operated in direct-flame configuration, with a propane flame impinging on the anode. Placing thermal insulation on the cathode dramatically increases cell temperature and performance. The optimum burner-to-cell gap height is a strong function of flame conditions. Cell performance at the optimum gap is determined within the region of stable non-coking conditions, with equivalence ratio from 1 to 1.9 and flow velocity from 100 to 300 cm s -1. In this region, performance is most strongly correlated to flow velocity and open circuit voltage. Themore » highest peak power density achieved is 633 mW cm -2 at 833°C, for equivalence ratio of 1.8 and flow velocity of 300 cm s -1. The cell starts to produce power within 10 s of being placed in the flame, and displays stable performance over 10 extremely rapid thermal cycles. The cell provides stable performance for >20 h of semi-continuous operation.« less

A self-cleaning Li-S battery enabled by a bifunctional redox mediator

NASA Astrophysics Data System (ADS)

Ren, Y. X.; Zhao, T. S.; Liu, M.; Zeng, Y. K.; Jiang, H. R.

2017-09-01

The polysulfide shuttle effect and lithium dendrite growth in lithium-sulfur (Li-S) batteries can repeatedly breach the anodic solid electrolyte interphase (SEI) over cycling. As a result, irreversible short-chain sulfide side products (Li2Sx, x = 1, 2) keep depositing on the Li anode, leading to the active material loss, increasing the Li+ transport resistance, and thereby reducing the cycle life. In this work, indium iodide (InI3) is investigated as a bifunctional electrolyte additive for Li-S batteries to protect the Li anode and decompose the side products spontaneously. On the one hand, Indium (In) is electrodeposited onto the Li anode prior to Li plating during the initial charging process, forming a chemically and mechanically stable SEI to prevent the Li anode from reacting with soluble polysulfide species to form Li2Sx (x = 1, 2) side products. On the other hand, by adequately overcharging the battery, the triiodide/iodide redox mediator is capable of chemically transforming side products deposited on the Li anode and separator into soluble polysulfides, which can be recycled by the cathode. It is shown that the battery with the InI3 additive exhibits a prolonged cycle life, and is capable of retrieving its capacity by a facile overcharging process.

Metallurgically lithiated SiOx anode with high capacity and ambient air compatibility

PubMed Central

Zhao, Jie; Lee, Hyun-Wook; Sun, Jie; Yan, Kai; Liu, Yayuan; Liu, Wei; Lu, Zhenda; Lin, Dingchang; Zhou, Guangmin; Cui, Yi

2016-01-01

A common issue plaguing battery anodes is the large consumption of lithium in the initial cycle as a result of the formation of a solid electrolyte interphase followed by gradual loss in subsequent cycles. It presents a need for prelithiation to compensate for the loss. However, anode prelithiation faces the challenge of high chemical reactivity because of the low anode potential. Previous efforts have produced prelithiated Si nanoparticles with dry air stability, which cannot be stabilized under ambient air. Here, we developed a one-pot metallurgical process to synthesize LixSi/Li2O composites by using low-cost SiO or SiO2 as the starting material. The resulting composites consist of homogeneously dispersed LixSi nanodomains embedded in a highly crystalline Li2O matrix, providing the composite excellent stability even in ambient air with 40% relative humidity. The composites are readily mixed with various anode materials to achieve high first cycle Coulombic efficiency (CE) of >100% or serve as an excellent anode material by itself with stable cyclability and consistently high CEs (99.81% at the seventh cycle and ∼99.87% for subsequent cycles). Therefore, LixSi/Li2O composites achieved balanced reactivity and stability, promising a significant boost to lithium ion batteries. PMID:27313206

Thylakoid-Deposited Micro-Pillar Electrodes for Enhanced Direct Extraction of Photosynthetic Electrons

PubMed Central

Ryu, DongHyun; Kim, Yong Jae; Kim, Seon Il; Hong, Hyeonaug; Ahn, Hyun S.

2018-01-01

Photosynthesis converts solar energy to electricity in a highly efficient manner. Since only water is needed as fuel for energy conversion, this highly efficient energy conversion process has been rigorously investigated. In particular, photosynthetic apparatus, such as photosystem II (PSII), photosystem I (PSI), or thylakoids, have been isolated from various plants to construct bio-hybrid anodes. Although PSII or PSI decorated anodes have shown potentials, there still remain challenges, such as poor stability of PSII-based systems or need for electron donors other than water molecules of PSI-based systems. Thylakoid membranes are relatively stable after isolation and they contain all the necessary photosynthetic apparatus including the PSII and PSI. To increase electrical connections between thylakoids and anodes, nanomaterials such as carbon nanotubes, nanowires, nanoparticles, or graphene have been employed. However, since they rely on the secondary electrical connections between thylakoids and anodes; it is desired to achieve larger direct contacts between them. Here, we aimed to develop micro-pillar (MP) array anodes to maximize direct contact with thylakoids. The thylakoid morphology was analyzed and the MP array was designed to maximize direct contact with thylakoids. The performance of MP anodes and a photosynthetic fuel cell based on MP electrodes was demonstrated and analyzed. PMID:29587387

Improved resistive switching characteristics of a Pt/HfO2/Pt resistor by controlling anode interface with forming and switching polarity

NASA Astrophysics Data System (ADS)

Jung, Yong Chan; Seong, Sejong; Lee, Taehoon; Kim, Seon Yong; Park, In-Sung; Ahn, Jinho

2018-03-01

The anode interface effects on the resistive switching characteristics of Pt/HfO2/Pt resistors are investigated by changing the forming and switching polarity. Resistive switching properties are evaluated and compared with the polarity operation procedures, such as the reset voltage (Vr), set voltage (Vs), and current levels at low and high resistance states. When the same forming and switching voltage polarity are applied to the resistor, their switching parameters are widely distributed. However, the opposite forming and switching voltage polarity procedures enhance the uniformity of the switching parameters. In particular, the Vs distribution is strongly affected by the voltage polarity variation. A model is proposed based on cone-shaped filament formation through the insulator and the cone diameter at the anode interface to explain the improved resistive switching characteristics under opposite polarity operation. The filament cone is thinner near the anode interface during the forming process; hence, the anode is altered by the application of a switching voltage with opposite polarity to the forming voltage polarity and the converted anode interface becomes the thicker part of the cone. The more uniform and stable switching behavior is attributed to control over the formation and rupture of the cone-shaped filaments at their thicker parts.

Development and test of photon-counting microchannel plate detector arrays for use on space telescopes

NASA Technical Reports Server (NTRS)

Timothy, J. G.

1976-01-01

The full sensitivity, dynamic range, and photometric stability of microchannel array plates(MCP) are incorporated into a photon-counting detection system for space operations. Components of the system include feedback-free MCP's for high gain and saturated output pulse-height distribution with a stable response; multi-anode readout arrays mounted in proximity focus with the output face of the MCP; and multi-layer ceramic headers to provide electrical interface between the anode array in a sealed detector tube and the associated electronics.

Stable silicon/3D porous N-doped graphene composite for lithium-ion battery anodes with self-assembly

NASA Astrophysics Data System (ADS)

Tang, Xiaofu; Wen, Guangwu; Song, Yan

2018-04-01

We fabricate a novel 3D N-doped graphene/silicon composite for lithium-ion battery anodes, with Si nanoparticles uniformly dispersed and thoroughly embedded in the N-doped graphene matrix. The favorable structure of the composite results in a BET surface area and an average mesopore diameter of 189.2 m2 g-1 and 3.82 nm, respectively. The composite delivers reversible capacities as high as 1132 mA h g-1 after 100 cycles under a current of 5 A g-1 and 1017 mA h g-1 after 200 cycles at 1 A g-1, and exhibits an improved rate capability. The present approach shows promise for the preparation of other high-performance anode materials for lithium-ion batteries.

Avoiding short circuits from zinc metal dendrites in anode by backside-plating configuration

PubMed Central

Higashi, Shougo; Lee, Seok Woo; Lee, Jang Soo; Takechi, Kensuke; Cui, Yi

2016-01-01

Portable power sources and grid-scale storage both require batteries combining high energy density and low cost. Zinc metal battery systems are attractive due to the low cost of zinc and its high charge-storage capacity. However, under repeated plating and stripping, zinc metal anodes undergo a well-known problem, zinc dendrite formation, causing internal shorting. Here we show a backside-plating configuration that enables long-term cycling of zinc metal batteries without shorting. We demonstrate 800 stable cycles of nickel–zinc batteries with good power rate (20 mA cm−2, 20 C rate for our anodes). Such a backside-plating method can be applied to not only zinc metal systems but also other metal-based electrodes suffering from internal short circuits. PMID:27263471

Multi-layered proton-conducting electrolyte

DOEpatents

Lee, Tae H.; Dorris, Stephen E.; Balachandran, Uthamalingam

2017-06-27

The present invention provides a multilayer anode/electrolyte assembly comprising a porous anode substrate and a layered solid electrolyte in contact therewith. The layered solid electrolyte includes a first dense layer of yttrium-doped barium zirconate (BZY), optionally including another metal besides Y, Ba, and Zr (e.g., a lanthanide metal such as Pr) on one surface thereof, a second dense layer of yttrium-doped barium cerate (BCY), and an interfacial layer between and contacting the BZY and BCY layers. The interfacial layer comprises a solid solution of the BZY and BCY electrolytes. The porous anode substrate comprises at least one porous ceramic material that is stable to carbon dioxide and water (e.g., porous BZY), as well as an electrically conductive metal and/or metal oxide (e.g., Ni, NiO, and the like).

A lithium-ion sulfur battery based on a carbon-coated lithium-sulfide cathode and an electrodeposited silicon-based anode.

PubMed

Agostini, Marco; Hassoun, Jusef; Liu, Jun; Jeong, Moongook; Nara, Hiroki; Momma, Toshiyuki; Osaka, Tetsuya; Sun, Yang-Kook; Scrosati, Bruno

2014-07-23

In this paper, we report a lithium-ion battery employing a lithium sulfide cathode and a silicon-based anode. The high capacity of the silicon anode and the high efficiency and cycling rate of the lithium sulfide cathode allowed optimal full cell balance. We show in fact that the battery operates with a very stable capacity of about 280 mAh g(-1) at an average voltage of 1.4 V. To the best of our knowledge, this battery is one of the rare examples of lithium-metal-free sulfur battery. Considering the high theoretical capacity of the employed electrodes, we believe that the battery here reported may be of potential interest as high-energy, safe, and low-cost power source for electric vehicles.

Controlled surface oxidation of multi-layered graphene anode to increase hole injection efficiency in organic electronic devices

NASA Astrophysics Data System (ADS)

Han, Tae-Hee; Kwon, Sung-Joo; Seo, Hong-Kyu; Lee, Tae-Woo

2016-03-01

Ultraviolet ozone (UVO) surface treatment of graphene changes its sp2-hybridized carbons to sp3-bonded carbons, and introduces oxygen-containing components. Oxidized graphene has a finite energy band gap, so UVO modification of the surface of a four-layered graphene anode increases its surface ionization potential up to ∼5.2 eV and improves the hole injection efficiency (η) in organic electronic devices by reducing the energy barrier between the graphene anode and overlying organic layers. By controlling the conditions of the UVO treatment, the electrical properties of the graphene can be tuned to improve η. This controlled surface modification of the graphene will provide a way to achieve efficient and stable flexible displays and solid-state lighting.

Avoiding short circuits from zinc metal dendrites in anode by backside-plating configuration

NASA Astrophysics Data System (ADS)

Higashi, Shougo; Lee, Seok Woo; Lee, Jang Soo; Takechi, Kensuke; Cui, Yi

2016-06-01

Portable power sources and grid-scale storage both require batteries combining high energy density and low cost. Zinc metal battery systems are attractive due to the low cost of zinc and its high charge-storage capacity. However, under repeated plating and stripping, zinc metal anodes undergo a well-known problem, zinc dendrite formation, causing internal shorting. Here we show a backside-plating configuration that enables long-term cycling of zinc metal batteries without shorting. We demonstrate 800 stable cycles of nickel-zinc batteries with good power rate (20 mA cm-2, 20 C rate for our anodes). Such a backside-plating method can be applied to not only zinc metal systems but also other metal-based electrodes suffering from internal short circuits.

Nanofiber-deposited porous platinum enables glucose fuel cell anodes with high current density in body fluids

NASA Astrophysics Data System (ADS)

Frei, Maxi; Erben, Johannes; Martin, Julian; Zengerle, Roland; Kerzenmacher, Sven

2017-09-01

The poisoning of platinum anodes by body-fluid constituents such as amino acids is currently the main hurdle preventing the application of abiotic glucose fuel cells as battery-independent power supply for medical implants. We present a novel anode material that enables continuous operation of glucose oxidation anodes in horse serum for at least 30 days at a current density of (7.2 ± 1.9) μA cm-2. The fabrication process is based on the electro-deposition of highly porous platinum onto a 3-dimensional carbon nanofiber support, leading to approximately 2-fold increased electrode roughness factors (up to 16500 ± 2300). The material's superior performance is not only related to its high specific surface area, but also to an improved catalytic activity and/or poisoning resistance. Presumably, this results from the micro- and nanostructure of the platinum deposits. This represents a major step forward in the development of implantable glucose fuel cells based on long-term stable platinum electrodes.

Enhanced electricity generation by triclosan and iron anodes in the three-chambered membrane bio-chemical reactor (TC-MBCR).

PubMed

Song, Jing; Liu, Lifen; Yang, Fenglin; Ren, Nanqi; Crittenden, John

2013-11-01

A three-chambered membrane bio-chemical reactor (TC-MBCR) was developed. The stainless steel membrane modules were used as cathodes and iron plates in the middle chamber served as the anode. The TC-MBCR was able to reduce fouling, remove triclosan (TCS) from a synthetic wastewater treatment and enhance electricity generation by ~60% compared with the cell voltage before TCS addition. The TC-MBCR system generated a relatively stable power output (cell voltage ~0.2V) and the corrosion of iron plates contributed to electricity generation together with microbes on iron anode. The permeation flow from anode to cathode chamber was considered important in electricity generation. In addition, the negatively charged cathode membrane and Fe(2+)/Fe(3+) released by iron plates mitigated membrane fouling by approximately 30%, as compared with the control. The removal of COD and total phosphorus was approximately 99% and 90%. The highest triclosan removal rate reached 97.9%. Copyright © 2013. Published by Elsevier Ltd.

Conductive Polymer Binder-Enabled SiO–Sn xCo yC z Anode for High-Energy Lithium-Ion Batteries

DOE PAGES

Zhao, Hui; Fu, Yanbao; Ling, Min; ...

2016-05-10

In this paper, a SiOSnCoC composite anode is assembled using a conductive polymer binder for the application in next-generation high energy density lithium-ion batteries. A specific capacity of 700 mAh/g is achieved at a 1C (900 mA/g) rate. A high active material loading anode with an areal capacity of 3.5 mAh/cm 2 is demonstrated by mixing SiOSnCoC with graphite. To compensate for the lithium loss in the first cycle, stabilized lithium metal powder (SLMP) is used for prelithiation; when paired with a commercial cathode, a stable full cell cycling performance with a 86% first cycle efficiency is realized. Finally, bymore » achieving these important metrics toward a practical application, this conductive polymer binder/SiOSnCoC anode system presents great promise to enable the next generation of high-energy lithium-ion batteries.« less

High rate and stable cycling of lithium metal anode

PubMed Central

Qian, Jiangfeng; Henderson, Wesley A.; Xu, Wu; Bhattacharya, Priyanka; Engelhard, Mark; Borodin, Oleg; Zhang, Ji-Guang

2015-01-01

Lithium metal is an ideal battery anode. However, dendrite growth and limited Coulombic efficiency during cycling have prevented its practical application in rechargeable batteries. Herein, we report that the use of highly concentrated electrolytes composed of ether solvents and the lithium bis(fluorosulfonyl)imide salt enables the high-rate cycling of a lithium metal anode at high Coulombic efficiency (up to 99.1%) without dendrite growth. With 4 M lithium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane as the electrolyte, a lithium|lithium cell can be cycled at 10 mA cm−2 for more than 6,000 cycles, and a copper|lithium cell can be cycled at 4 mA cm−2 for more than 1,000 cycles with an average Coulombic efficiency of 98.4%. These excellent performances can be attributed to the increased solvent coordination and increased availability of lithium ion concentration in the electrolyte. Further development of this electrolyte may enable practical applications for lithium metal anode in rechargeable batteries. PMID:25698340

An artificial interphase enables reversible magnesium chemistry in carbonate electrolytes.

PubMed

Son, Seoung-Bum; Gao, Tao; Harvey, Steve P; Steirer, K Xerxes; Stokes, Adam; Norman, Andrew; Wang, Chunsheng; Cresce, Arthur; Xu, Kang; Ban, Chunmei

2018-05-01

Magnesium-based batteries possess potential advantages over their lithium counterparts. However, reversible Mg chemistry requires a thermodynamically stable electrolyte at low potential, which is usually achieved with corrosive components and at the expense of stability against oxidation. In lithium-ion batteries the conflict between the cathodic and anodic stabilities of the electrolytes is resolved by forming an anode interphase that shields the electrolyte from being reduced. This strategy cannot be applied to Mg batteries because divalent Mg 2+ cannot penetrate such interphases. Here, we engineer an artificial Mg 2+ -conductive interphase on the Mg anode surface, which successfully decouples the anodic and cathodic requirements for electrolytes and demonstrate highly reversible Mg chemistry in oxidation-resistant electrolytes. The artificial interphase enables the reversible cycling of a Mg/V 2 O 5 full-cell in the water-containing, carbonate-based electrolyte. This approach provides a new avenue not only for Mg but also for other multivalent-cation batteries facing the same problems, taking a step towards their use in energy-storage applications.

Structural analysis of PrBaMn2O5+δ under SOFC anode conditions by in-situ neutron powder diffraction

NASA Astrophysics Data System (ADS)

Tomkiewicz, Alex C.; Tamimi, Mazin A.; Huq, Ashfia; McIntosh, Steven

2016-10-01

The crystal structure and oxygen stoichiometry of the proposed double perovskite solid oxide fuel cell (SOFC) anode material PrBaMn2O5+δ were determined under SOFC anode conditions via in-situ neutron diffraction. Measurements were performed in reducing atmospheres between 692 K and 984 K. The structure was fit to a tetragonal (space group P4/mmm) layered double perovskite structure with alternating Pr and Ba A-site cation layers. Under all conditions examined, the oxygen sites in the Ba and Mn layers were fully occupied, while the sites in the Pr layer were close to completely vacant. The results of the neutron diffraction experiments are compared to previous thermogravimetric analysis experiments to verify the accuracy of both experiments. PrBaMn2O5+δ was shown to be stable over a wide range of reducing atmospheres similar to anode operating conditions in solid oxide fuel cells without significant structural changes.

Nanoporous hard data: optical encoding of information within nanoporous anodic alumina photonic crystals.

PubMed

Santos, Abel; Law, Cheryl Suwen; Pereira, Taj; Losic, Dusan

2016-04-21

Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for developing advanced nanophotonic tools for a wide range of applications, including sensing, photonic tagging, self-reporting drug releasing systems and secure encoding of information.

SiC Nanofibers as Long-Life Lithium-Ion Battery Anode Materials.

PubMed

Sun, Xuejiao; Shao, Changzhen; Zhang, Feng; Li, Yi; Wu, Qi-Hui; Yang, Yonggang

2018-01-01

The development of high energy lithium-ion batteries (LIBs) has spurred the designing and production of novel anode materials to substitute currently commercial using graphitic materials. Herein, twisted SiC nanofibers toward LIBs anode materials, containing 92.5 wt% cubic β-SiC and 7.5 wt% amorphous C, were successfully synthesized from resin-silica composites. The electrochemical measurements showed that the SiC-based electrode delivered a stable reversible capacity of 254.5 mAh g -1 after 250 cycles at a current density of 0.1 A g -1 . It is interesting that a high discharge capacity of 540.1 mAh g -1 was achieved after 500 cycles at an even higher current density of 0.3 A g -1 , which is higher than the theoretical capacity of graphite. The results imply that SiC nanomaterials are potential anode candidate for LIBs with high stability due to their high structure stability as supported with the transmission electron microscopy images.

An artificial interphase enables reversible magnesium chemistry in carbonate electrolytes

NASA Astrophysics Data System (ADS)

Son, Seoung-Bum; Gao, Tao; Harvey, Steve P.; Steirer, K. Xerxes; Stokes, Adam; Norman, Andrew; Wang, Chunsheng; Cresce, Arthur; Xu, Kang; Ban, Chunmei

2018-05-01

Magnesium-based batteries possess potential advantages over their lithium counterparts. However, reversible Mg chemistry requires a thermodynamically stable electrolyte at low potential, which is usually achieved with corrosive components and at the expense of stability against oxidation. In lithium-ion batteries the conflict between the cathodic and anodic stabilities of the electrolytes is resolved by forming an anode interphase that shields the electrolyte from being reduced. This strategy cannot be applied to Mg batteries because divalent Mg2+ cannot penetrate such interphases. Here, we engineer an artificial Mg2+-conductive interphase on the Mg anode surface, which successfully decouples the anodic and cathodic requirements for electrolytes and demonstrate highly reversible Mg chemistry in oxidation-resistant electrolytes. The artificial interphase enables the reversible cycling of a Mg/V2O5 full-cell in the water-containing, carbonate-based electrolyte. This approach provides a new avenue not only for Mg but also for other multivalent-cation batteries facing the same problems, taking a step towards their use in energy-storage applications.

Lithium storage in structurally tunable carbon anode derived from sustainable source

DOE PAGES

Lim, Daw Gen; Kim, Kyungho; Razdan, Mayuri; ...

2017-09-01

Here, a meticulous solid state chemistry approach has been developed for the synthesis of carbon anode from a sustainable source. The reaction mechanism of carbon formation during pyrolysis of sustainable feed-stock was studied in situ by employing Raman microspectroscopy. No Raman spectral changes observed below 160°C (thermally stable precursor) followed by color change, however above 280°C characteristic D and G bands of graphitic carbon are recorded. Derived carbon particles exhibited high specific surface area with low structural ordering (active carbons) to low specific surface area with high graphitic ordering as a function of increasing reaction temperature. Carbons synthesized at 600°Cmore » demonstrated enhanced reversible lithiation capacity (390 mAh g -1), high charge-discharge rate capability, and stable cycle life. On the contrary, carbons synthesized at higher temperatures (>1200°C) produced more graphite-like structure yielding longer specific capacity retention with lower reversible capacity.« less

Composite lithium metal anode by melt infusion of lithium into a 3D conducting scaffold with lithiophilic coating

PubMed Central

Liang, Zheng; Lin, Dingchang; Zhao, Jie; Lu, Zhenda; Liu, Yayuan; Liu, Chong; Lu, Yingying; Wang, Haotian; Yan, Kai; Tao, Xinyong; Cui, Yi

2016-01-01

Lithium metal-based battery is considered one of the best energy storage systems due to its high theoretical capacity and lowest anode potential of all. However, dendritic growth and virtually relative infinity volume change during long-term cycling often lead to severe safety hazards and catastrophic failure. Here, a stable lithium–scaffold composite electrode is developed by lithium melt infusion into a 3D porous carbon matrix with “lithiophilic” coating. Lithium is uniformly entrapped on the matrix surface and in the 3D structure. The resulting composite electrode possesses a high conductive surface area and excellent structural stability upon galvanostatic cycling. We showed stable cycling of this composite electrode with small Li plating/stripping overpotential (<90 mV) at a high current density of 3 mA/cm2 over 80 cycles. PMID:26929378

Soft template strategy to synthesize iron oxide-titania yolk-shell nanoparticles as high-performance anode materials for lithium-ion battery applications.

PubMed

Lim, Joohyun; Um, Ji Hyun; Ahn, Jihoon; Yu, Seung-Ho; Sung, Yung-Eun; Lee, Jin-Kyu

2015-05-18

Yolk-shell-structured nanoparticles with iron oxide core, void, and a titania shell configuration are prepared by a simple soft template method and used as the anode material for lithium ion batteries. The iron oxide-titania yolk-shell nanoparticles (IO@void@TNPs) exhibit a higher and more stable capacity than simply mixed nanoparticles of iron oxide and hollow titania because of the unique structure obtained by the perfect separation between iron oxide nanoparticles, in combination with the adequate internal void space provided by stable titania shells. Moreover, the structural effect of IO@void@TNPs clearly demonstrates that the capacity retention value after 50 cycles is approximately 4 times that for IONPs under harsh operating conditions, that is, when the temperature is increased to 80 °C. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Slotted Anode on Gas Bubble Behaviors in Aluminum Reduction Cell

NASA Astrophysics Data System (ADS)

Sun, Meijia; Li, Baokuan; Li, Linmin; Wang, Qiang; Peng, Jianping; Wang, Yaowu; Cheung, Sherman C. P.

2017-12-01

In the aluminum reduction cells, gas bubbles are generated at the bottom of the anode which eventually reduces the effective current contact area and the system efficiency. To encourage the removal of gas bubbles, slotted anode has been proposed and increasingly adopted by some industrial aluminum reduction cells. Nonetheless, the exact gas bubble removal mechanisms are yet to be fully understood. A three-dimensional (3D) transient, multiphase flow mathematical model coupled with magnetohydrodynamics has been developed to investigate the effect of slotted anode on the gas bubble movement. The Eulerian volume of fluid approach is applied to track the electrolyte (bath)-molten aluminum (metal) interface. Meanwhile, the Lagrangian discrete particle model is employed to handle the dynamics of gas bubbles with considerations of the buoyancy force, drag force, virtual mass force, and pressure gradient force. The gas bubble coalescence process is also taken into account based on the O'Rourke's algorithm. The two-way coupling between discrete bubbles and fluids is achieved by the inter-phase momentum exchange. Numerical predictions are validated against the anode current variation in an industrial test. Comparing the results using slotted anode with the traditional one, the time-averaged gas bubble removal rate increases from 36 to 63 pct; confirming that the slotted anode provides more escaping ways and shortens the trajectories for gas bubbles. Furthermore, the slotted anode also reduces gas bubble's residence time and the probability of coalescence. Moreover, the bubble layer thickness in aluminum cell with slotted anode is reduced about 3.5 mm (17.4 pct), so the resistance can be cut down for the sake of energy saving and the metal surface fluctuation amplitude is significantly reduced for the stable operation due to the slighter perturbation with smaller bubbles.

Enhanced sulfur tolerance of nickel-based anodes for oxygen-ion conducting solid oxide fuel cells by incorporating a secondary water storing phase.

PubMed

Wang, Feng; Wang, Wei; Qu, Jifa; Zhong, Yijun; Tade, Mose O; Shao, Zongping

2014-10-21

In this work, a Ni+BaZr(0.4)Ce(0.4)Y(0.2)O(3-δ) (Ni+BZCY) anode with high water storage capability is used to increase the sulfur tolerance of nickel electrocatalysts for solid oxide fuel cells (SOFCs) with an oxygen-ion conducting Sm(0.2)Ce(0.8)O(1.9) (SDC) electrolyte. Attractive power outputs are still obtained for the cell with a Ni+BZCY anode that operates on hydrogen fuels containing 100-1000 ppm of H2S, while for a similar cell with a Ni+SDC anode, it displays a much reduced performance by introducing only 100 ppm of H2S into hydrogen. Operating on a hydrogen fuel containing 100 ppm of H2S at 600 °C and a fixed current density of 200 mA cm(-2), a stable power output of 148 mW cm(-2) is well maintained for a cell with a Ni+BZCY anode within a test period of 700 min, while it was decreased from an initial value of 137 mW cm(-2) to only 81 mW cm(-2) for a similar cell with a Ni+SDC anode after a test period of only 150 min. After the stability test, a loss of the Ni percolating network and reaction between nickel and sulfur appeared over the Ni+SDC anode, but it is not observed for the Ni+BZCY anode. This result highly promises the use of water-storing BZCY as an anode component to improve sulfur tolerance for SOFCs with an oxygen-ion conducting SDC electrolyte.

34 CFR 367.11 - What assurances must a DSA include in its application?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 34 Education 2 2014-07-01 2013-07-01 true What assurances must a DSA include in its application? 367.11 Section 367.11 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION INDEPENDENT LIVING...

34 CFR 367.11 - What assurances must a DSA include in its application?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 34 Education 2 2012-07-01 2012-07-01 false What assurances must a DSA include in its application? 367.11 Section 367.11 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION INDEPENDENT LIVING...

34 CFR 367.11 - What assurances must a DSA include in its application?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 34 Education 2 2013-07-01 2013-07-01 false What assurances must a DSA include in its application? 367.11 Section 367.11 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION INDEPENDENT LIVING...

34 CFR 367.41 - When may a DSA award grants or contracts?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 2 2010-07-01 2010-07-01 false When may a DSA award grants or contracts? 367.41 Section 367.41 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION INDEPENDENT LIVING SERVICES FOR...

34 CFR 367.41 - When may a DSA award grants or contracts?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 34 Education 2 2011-07-01 2010-07-01 true When may a DSA award grants or contracts? 367.41 Section 367.41 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION INDEPENDENT LIVING SERVICES FOR...

34 CFR 367.10 - How does a designated State agency (DSA) apply for an award?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 34 Education 2 2010-07-01 2010-07-01 false How does a designated State agency (DSA) apply for an award? 367.10 Section 367.10 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION INDEPENDENT...

34 CFR 367.10 - How does a designated State agency (DSA) apply for an award?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 34 Education 2 2011-07-01 2010-07-01 true How does a designated State agency (DSA) apply for an award? 367.10 Section 367.10 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION INDEPENDENT...

The role of time-resolved imaging of contrast kinetics (TRICKS) magnetic resonance angiography (MRA) in the evaluation of head-neck vascular anomalies: a preliminary experience.

PubMed

Romano, A; Tavanti, F; Rossi Espagnet, M C; Terenzi, V; Cassoni, A; Suma, G; Boellis, A; Pierallini, A; Valentini, V; Bozzao, A

2015-01-01

In this preliminary report, we describe our experience with time-resolved imaging of contrast kinetics-MR angiography (TRICKS-MRA) in the assessment of head-neck vascular anomalies (HNVAs). We prospectively studied six consecutive patients with clinically suspected or diagnosed HNVAs. All of them underwent TRICKS-MRA of the head and neck as part of the routine for treatment planning. A digital subtraction angiography (DSA) was also performed. TRICKS-MRA could be achieved in all cases. Three subjects were treated based on TRICKS-MRA imaging findings and subsequent DSA examination. In all of them, DSA confirmed the vascular architecture of HNVAs shown by TRICKS-MRA. In the other three patients, a close follow up to assess the evolution of the suspected haemangioma was preferred. TRICKS sequences add important diagnostic information in cases of HNVAs, helpful for therapeutic decisions and post-treatment follow up. We recommend TRICKS-MRA use (if technically possible) as part of routine MRI protocol for HNVAs, representing a possible alternative imaging tool to conventional DSA.

Using process monitor wafers to understand directed self-assembly defects

NASA Astrophysics Data System (ADS)

Cao, Yi; Her, YoungJun; Delgadillo, Paulina R.; Vandenbroeck, Nadia; Gronheid, Roel; Chan, Boon Teik; Hashimoto, Yukio; Romo, Ainhoa; Somervell, Mark; Nafus, Kathleen; Nealey, Paul F.

2013-03-01

As directed self-assembly (DSA) has gained momentum over the past few years, questions about its application to high volume manufacturing have arisen. One of the major concerns is about the fundamental limits of defectivity that can be attained with the technology. If DSA applications demonstrate defectivity that rivals of traditional lithographic technologies, the pathway to the cost benefits of the technology creates a very compelling case for its large scale implementation. To address this critical question, our team at IMEC has established a process monitor flow to track the defectivity behaviors of an exemplary chemo-epitaxy application for printing line/space patterns. Through establishing this baseline, we have been able to understand both traditional lithographic defect sources in new materials as well as new classes of assembly defects associated with DSA technology. Moreover, we have explored new materials and processing to lower the level of the defectivity baseline. The robustness of the material sets and process is investigated as well. In this paper, we will report the understandings learned from the IMEC DSA process monitor flow.

Supporting Dynamic Spectrum Access in Heterogeneous LTE+ Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luiz A. DaSilva; Ryan E. Irwin; Mike Benonis

As early as 2014, mobile network operators’ spectral capac- ity is expected to be overwhelmed by the demand brought on by new devices and applications. With Long Term Evo- lution Advanced (LTE+) networks likely as the future one world 4G standard, network operators may need to deploy a Dynamic Spectrum Access (DSA) overlay in Heterogeneous Networks (HetNets) to extend coverage, increase spectrum efficiency, and increase the capacity of these networks. In this paper, we propose three new management frameworks for DSA in an LTE+ HetNet: Spectrum Accountability Client, Cell Spectrum Management, and Domain Spectrum Man- agement. For these spectrum managementmore » frameworks, we define protocol interfaces and operational signaling scenar- ios to support cooperative sensing, spectrum lease manage- ment, and alarm scenarios for rule adjustment. We also quan- tify, through integer programs, the benefits of using DSA in an LTE+ HetNet, that can opportunistically reuse vacant TV and GSM spectrum. Using integer programs, we consider a topology using Geographic Information System data from the Blacksburg, VA metro area to assess the realistic benefits of DSA in an LTE+ HetNet.« less

Effect of nitrogen on high temperature low cycle fatigue behaviors in type 316L stainless steel

NASA Astrophysics Data System (ADS)

Kim, Dae Whan; Ryu, Woo-Seog; Hong, Jun Hwa; Choi, Si-Kyung

1998-04-01

Strain-controlled low cycle fatigue (LCF) tests were conducted in the temperature range of RT-600°C and air atmosphere to investigate the nitrogen effect on LCF behavior of type 316L stainless steels with different nitrogen contents (0.04-0.15%). The waveform of LCF was a symmetrical triangle with a strain amplitude of ±0.5% and a constant strain rate of 2×10 -3/s was employed for most tests. Cyclic stress response of the alloys exhibited a gradual cyclic softening at RT, but a cyclic hardening at an early stage of fatigue life at 300-600°C. The hardening at high temperature was attributed to dynamic strain aging (DSA). Nitrogen addition decreased hardening magnitude (maximum cyclic stress — first cyclic stress) because nitrogen retarded DSA for these conditions. The dislocation structures were changed from cell to planar structure with increasing temperature and nitrogen addition by DSA and short range order (SRO). Fatigue life was a maximum at 0.1% nitrogen content, which was attributed to the balance between DSA and SRO.

Stability of Electrodeposition at Solid-Solid Interfaces and Implications for Metal Anodes

NASA Astrophysics Data System (ADS)

Ahmad, Zeeshan; Viswanathan, Venkatasubramanian

2017-08-01

We generalize the conditions for stable electrodeposition at isotropic solid-solid interfaces using a kinetic model which incorporates the effects of stresses and surface tension at the interface. We develop a stability diagram that shows two regimes of stability: a previously known pressure-driven mechanism and a new density-driven stability mechanism that is governed by the relative density of metal in the two phases. We show that inorganic solids and solid polymers generally do not lead to stable electrodeposition, and provide design guidelines for achieving stable electrodeposition.

Visualization and Classification of Deeply Seated Collateral Networks in Moyamoya Angiopathy with 7T MRI.

PubMed

Matsushige, T; Kraemer, M; Sato, T; Berlit, P; Forsting, M; Ladd, M E; Jabbarli, R; Sure, U; Khan, N; Schlamann, M; Wrede, K H

2018-06-07

Collateral networks in Moyamoya angiopathy have a complex angioarchitecture difficult to comprehend on conventional examinations. This study aimed to evaluate morphologic patterns and the delineation of deeply seated collateral networks using ultra-high-field MRA in comparison with conventional DSA. Fifteen white patients with Moyamoya angiopathy were investigated in this prospective trial. Sequences acquired at 7T were TOF-MRA with 0.22 × 0.22 × 0.41 mm 3 resolution and MPRAGE with 0.7 × 0.7 × 0.7 mm 3 resolution. Four raters evaluated the presence of deeply seated collateral networks and image quality in a consensus reading of DSA, TOF-MRA, and MPRAGE using a 5-point scale in axial source images and maximum intensity projections. Delineation of deeply seated collateral networks by different imaging modalities was compared by means of the McNemar test, whereas image quality was compared using the Wilcoxon signed-rank test. The relevant deeply seated collateral networks were classified into 2 categories and 6 pathways. A total of 100 collateral networks were detected on DSA; 106, on TOF-MRA; and 73, on MPRAGE. Delineation of deeply seated collateral networks was comparable between TOF-MRA and DSA ( P = .25); however, both were better than MPRAGE ( P < .001). This study demonstrates excellent delineation of 6 distinct deeply seated collateral network pathways in Moyamoya angiopathy in white adults using 7T TOF-MRA, comparable to DSA. © 2018 by American Journal of Neuroradiology.

Outcome after Desensitization in HLA or ABO-Incompatible Kidney Transplant Recipients: A Single Center Experience

PubMed Central

Kauke, Teresa; Klimaschewski, Sandra; Schoenermarck, Ulf; Fischereder, Michael; Dick, Andrea; Guba, Markus; Stangl, Manfred; Werner, Jens; Meiser, Bruno; Habicht, Antje

2016-01-01

Background The shortage of deceased donors led to an increase of living donor kidney (LDK) transplantations performed in the presence of donor-specific antibodies (DSA) or ABO incompatibility (ABOi) using various desensitization protocols. Methods We herein analyzed 26 ABOi and 8 Luminex positive DSA patients who were successfully desensitized by anti-CD20, antigen-specific immunoadsorption and/or plasmapheresis to receive an LDK transplant. Twenty LDK recipients with non-donor-specific HLA-antibodies (low risk) and 32 without anti-HLA antibodies (no risk) served as control groups. Results 1-year graft survival rate and renal function was similar in all 4 groups (creatinine: 1.63 ± 0.5 vs 1.78 ± 0.6 vs 1.64 ± 0.5 vs 1.6 ± 0.3 mg/dl in ABOi, DSA, low risk and no risk group). The incidence of acute T-cell mediated rejections did not differ between the 4 groups (15% vs 12, 5% vs 15% vs 22% in ABOi, DSA, low risk and no risk), while antibody-mediated rejections were only found in the DSA (25%) and ABOi (7.5%) groups. Incidence of BK nephropathy (BKVN) was significantly more frequent after desensitization as compared to controls (5/34 vs 0/52, p = 0.03). Conclusion We demonstrate favorable short-term allograft outcome in LDK transplant recipients after desensitization. However, the desensitization was associated with an increased risk of BKVN. PMID:26730981

Efficacy of induction therapy with ATG and intravenous immunoglobulins in patients with low-level donor-specific HLA-antibodies.

PubMed

Bächler, K; Amico, P; Hönger, G; Bielmann, D; Hopfer, H; Mihatsch, M J; Steiger, J; Schaub, S

2010-05-01

Low-level donor-specific HLA-antibodies (HLA-DSA) (i.e. detectable by single-antigen flow beads, but negative by complement-dependent cytotoxicity crossmatch) represent a risk factor for early allograft rejection. The short-term efficacy of an induction regimen consisting of polyclonal anti-T-lymphocyte globulin (ATG) and intravenous immunoglobulins (IvIg) in patients with low-level HLA-DSA is unknown. In this study, we compared 67 patients with low-level HLA-DSA not having received ATG/IvIg induction (historic control) with 37 patients, who received ATG/IvIg induction. The two groups were equal regarding retransplants, HLA-matches, number and class of HLA-DSA. The overall incidence of clinical/subclinical antibody-mediated rejection (AMR) was lower in the ATG/IvIg than in the historic control group (38% vs. 55%; p = 0.03). This was driven by a significantly lower rate of clinical AMR (11% vs. 46%; p = 0.0002). Clinical T-cell-mediated rejection (TCR) was significantly lower in the ATG/IvIg than in the historic control group (0% vs. 50%; p < 0.0001). Within the first year, allograft loss due to AMR occurred in 7.5% in the historic control and in 0% in the ATG/IvIg group. We conclude that in patients with low-level HLA-DSA, ATG/IvIg induction significantly reduces TCR and the severity of AMR, but the high rate of subclinical AMR suggests an insufficient control of the humoral immune response.

Combining Diffusive Shock Acceleration with Acceleration by Contracting and Reconnecting Small-scale Flux Ropes at Heliospheric Shocks

NASA Astrophysics Data System (ADS)

le Roux, J. A.; Zank, G. P.; Webb, G. M.; Khabarova, O. V.

2016-08-01

Computational and observational evidence is accruing that heliospheric shocks, as emitters of vorticity, can produce downstream magnetic flux ropes and filaments. This led Zank et al. to investigate a new paradigm whereby energetic particle acceleration near shocks is a combination of diffusive shock acceleration (DSA) with downstream acceleration by many small-scale contracting and reconnecting (merging) flux ropes. Using a model where flux-rope acceleration involves a first-order Fermi mechanism due to the mean compression of numerous contracting flux ropes, Zank et al. provide theoretical support for observations that power-law spectra of energetic particles downstream of heliospheric shocks can be harder than predicted by DSA theory and that energetic particle intensities should peak behind shocks instead of at shocks as predicted by DSA theory. In this paper, a more extended formalism of kinetic transport theory developed by le Roux et al. is used to further explore this paradigm. We describe how second-order Fermi acceleration, related to the variance in the electromagnetic fields produced by downstream small-scale flux-rope dynamics, modifies the standard DSA model. The results show that (I) this approach can qualitatively reproduce observations of particle intensities peaking behind the shock, thus providing further support for the new paradigm, and (II) stochastic acceleration by compressible flux ropes tends to be more efficient than incompressible flux ropes behind shocks in modifying the DSA spectrum of energetic particles.

COMBINING DIFFUSIVE SHOCK ACCELERATION WITH ACCELERATION BY CONTRACTING AND RECONNECTING SMALL-SCALE FLUX ROPES AT HELIOSPHERIC SHOCKS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Roux, J. A.; Zank, G. P.; Webb, G. M.

2016-08-10

Computational and observational evidence is accruing that heliospheric shocks, as emitters of vorticity, can produce downstream magnetic flux ropes and filaments. This led Zank et al. to investigate a new paradigm whereby energetic particle acceleration near shocks is a combination of diffusive shock acceleration (DSA) with downstream acceleration by many small-scale contracting and reconnecting (merging) flux ropes. Using a model where flux-rope acceleration involves a first-order Fermi mechanism due to the mean compression of numerous contracting flux ropes, Zank et al. provide theoretical support for observations that power-law spectra of energetic particles downstream of heliospheric shocks can be harder thanmore » predicted by DSA theory and that energetic particle intensities should peak behind shocks instead of at shocks as predicted by DSA theory. In this paper, a more extended formalism of kinetic transport theory developed by le Roux et al. is used to further explore this paradigm. We describe how second-order Fermi acceleration, related to the variance in the electromagnetic fields produced by downstream small-scale flux-rope dynamics, modifies the standard DSA model. The results show that (i) this approach can qualitatively reproduce observations of particle intensities peaking behind the shock, thus providing further support for the new paradigm, and (ii) stochastic acceleration by compressible flux ropes tends to be more efficient than incompressible flux ropes behind shocks in modifying the DSA spectrum of energetic particles.« less

Rational design of Fe3O4@C yolk-shell nanorods constituting a stable anode for high-performance Li/Na-ion batteries.

PubMed

Wang, Beibei; Zhang, Xing; Liu, Xiaojie; Wang, Gang; Wang, Hui; Bai, Jintao

2018-05-24

In the current research project, we have prepared a novel Fe 3 O 4 @mesoporous carbon nanorod (denoted as Fe 3 O 4 @C) anode with yolk-shell structure for Li/Na-ion batteries via one-pot and surfactant-free synthesis strategy. The yolk-shell structure consists of Fe 3 O 4 nanorod yolk completely protected by a well-conductive mesoporous carbon shell. The substantial void space in the Fe 3 O 4 @C yolk-shell nanorod can not only accommodate the full volume expansion of inner Fe 3 O 4 nanorod, but also preserve the structural integrity of the Fe 3 O 4 @C anode and develop a stable SEI film on the outside mesoporous carbon shell during the repeated Li + /Na + insertion/extraction processes. As for lithium storage, the Fe 3 O 4 @C electrode exhibits a high specific capacity (1247 mAh g -1 ), stable cycling performance (a specific capacity of 954 mAh g -1 after 200 cycles at a current density of 0.5 A g -1 ) and excellent rate capability (specific capabilities of 1122, 958, 783, 577, and 374 mAh g -1 at 0.5, 1, 2, 4, and 8 A g -1 , respectively). As for sodium storage, the Fe 3 O 4 @C yolk-shell nanorods also maintain a reversible capacity of approximate 424 mAh g -1 at 0.1 A g -1 after 100 cycles. Copyright © 2018. Published by Elsevier Inc.

An Insoluble Titanium-Lead Anode for Sulfate Electrolytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferdman, Alla

2005-05-11

The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead compositemore » material were investigated. The material containing 20-30 vol.% of lead had optimal combination of mechanical and electrochemical properties. Optimal process parameters to manufacture the anodes were identified. Prototypes having optimized composition and structure were produced for testing in operating conditions of copper electrowinning and EMD production. Bench-scale, mini-pilot scale and pilot scale tests were performed. The test anodes were of both a plate design and a flow-through cylindrical design. The cylindrical anodes were composed of cylinders containing titanium inner rods and fitting over titanium-lead bushings. The cylindrical design allows the electrolyte to flow through the anode, which enhances diffusion of the electrolyte reactants. The cylindrical anodes demonstrate higher mass transport capabilities and increased electrical efficiency compared to the plate anodes. Copper electrowinning represents the primary target market for the titanium-lead anode. A full-size cylindrical anode performance in copper electrowinning conditions was monitored over a year. The test anode to cathode voltage was stable in the 1.8 to 2.0 volt range. Copper cathode morphology was very smooth and uniform. There was no measurable anode weight loss during this time period. Quantitative chemical analysis of the anode surface showed that the lead content after testing remained at its initial level. No lead dissolution or transfer from the anode to the product occurred.A key benefit of the titanium-lead anode design is that cobalt additions to copper electrolyte should be eliminated. Cobalt is added to the electrolyte to help stabilize the lead oxide surface of conventional lead anodes. The presence of the titanium intimately mixed with the lead should eliminate the need for cobalt stabilization of the lead surface. The anode should last twice as long as the conventional lead anode. Energy savings should be achieved due to minimizing and stabilizing the anode-cathode distance in the electrowinning cells. The anode is easily substitutable into existing tankhouses without a rectifier change.The copper electrowinning test data indicate that the titanium-lead anode is a good candidate for further testing as a possible replacement for a conventional lead anode. A key consideration is the cost. Titanium costs have increased. One of the ways to get the anode cost down is manufacturing the anodes with fewer cylinders. Additional prototypes having different number of cylinders were constructed for a long-term commercial testing in a circuit without cobalt. The objective of the testing is to evaluate the need for cobalt, investigate the effect of decreasing the number of cylinders on the anode performance, and to optimize further the anode design in order to meet the operating requirements, minimize the voltage, maximize the life of the anode, and to balance this against a reasonable cost for the anode. It is anticipated that after testing of the additional prototypes, a whole cell commercial test will be conducted to complete evaluation of the titanium-lead anode costs/benefits.« less

Follow-up of intracranial aneurysms treated with stent-assisted coiling: Comparison of contrast-enhanced MRA, time-of-flight MRA, and digital subtraction angiography.

PubMed

Marciano, David; Soize, Sébastien; Metaxas, Georgios; Portefaix, Christophe; Pierot, Laurent

2017-02-01

Data about non-invasive follow-up of aneurysm after stent-assisted coiling is scarce. We aimed to compare time-of-flight (TOF) magnetic resonance angiography (MRA) (3D-TOF-MRA) and contrast-enhanced MRA (CE-MRA) at 3-Tesla, with digital subtraction angiography (DSA) for evaluating aneurysm occlusion and parent artery patency after stent-assisted coiling. In this retrospective single-center study, patients were included if they had an intracranial aneurysm treated by stent-assisted coiling between March 2008 and June 2015, followed with both MRA sequences (3D-TOF-MRA and CE-MRA) at 3-Tesla and DSA, performed in an interval<48hours. Thirty-five aneurysms were included. Regarding aneurysm occlusion evaluation, agreement with DSA was better for CE-MRA (K=0.53) than 3D-TOF-MRA (K=0.28). Diagnostic accuracies for aneurysm remnant depiction were similar for 3D-TOF-MRA and CE-MRA (P=1). Both 3D-TOF-MRA (K=0.05) and CE-MRA (K=-0.04) were unable to detect pathological vessel compared to DSA, without difference in accuracy (P=0.68). For parent artery occlusion detection, agreement with DSA was substantial for 3D-TOF-MRA (K=0.64) and moderate for CE-MRA (K=0.45), with similar good diagnostic accuracies (P=1). After stent-assisted coiling treatment, 3D-TOF-MRA and CE-MRA demonstrated good accuracy to detect aneurysm remnant (but tended to overestimation). Although CE-MRA agreement with DSA was better, there was no statistical difference between 3D-TOF-MRA and CE-MRA accuracies. Both MRAs were unable to provide a precise evaluation of in-stent status but could detect parent vessel occlusion. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Dynamic Strain Aging Phenomena and Tensile Response of Medium-Mn TRIP Steel

NASA Astrophysics Data System (ADS)

Field, Daniel M.; Van Aken, David C.

2018-04-01

Dynamic strain aging (DSA) and rapid work hardening are typical behaviors observed in medium-Mn transformation-induced plasticity (TRIP) steel. Three alloys with manganese ranging from 10.2 to 13.8 wt pct with calculated room temperature stacking fault energies varying from - 2.1 to 0.7 mJ/m2 were investigated. Significant serrations were observed in the stress-strain behavior for two of the steels and the addition of 4.6 wt pct chromium was effective in significantly reducing the occurrence of DSA. Addition of chromium to the alloy reduced DSA by precipitation of M23(C,N)6 during batch annealing at 873 K (600 °C) for 20 hours. Three distinct DSA mechanisms were identified: one related to manganese ordering in stacking faults associated with ɛ-martensite and austenite interface, with activation energies for the onset and termination of DSA being 145 and 277 kJ/mol. A second mechanism was associated with carbon diffusion in γ-austenite where Mn-C bonding added to the total binding energy, and activation energies of 88 and 155 kJ/mol were measured for the onset and termination of DSA. A third mechanism was attributed to dislocation pinning and unpinning by nitrogen in α-ferrite with activation energies of 64 and 123 kJ/mol being identified. Tensile behaviors of the three medium manganese steels were studied in both the hot band and batch annealed after cold working conditions. Ultimate tensile strengths ranged from 1310 to 1404 MPa with total elongation of 24.1 to 34.1 pct. X-ray diffraction (XRD) was used to determine the transformation response of the steels using interrupted tensile tests at room temperature. All three of the processed steels showed evidence of two-stage TRIP where γ-austenite first transformed to ɛ-martensite, and subsequently transformed to α-martensite.

Transarterial onyx embolization of cranial dural arteriovenous fistulas: long-term follow-up.

PubMed

Chandra, R V; Leslie-Mazwi, T M; Mehta, B P; Yoo, A J; Rabinov, J D; Pryor, J C; Hirsch, J A; Nogueira, R G

2014-09-01

Endovascular therapy with liquid embolic agents is a common treatment strategy for cranial dural arteriovenous fistulas. This study evaluated the long-term effectiveness of transarterial Onyx as the single embolic agent for curative embolization of noncavernous cranial dural arteriovenous fistulas. We performed a retrospective review of 40 consecutive patients with 41 cranial dural arteriovenous fistulas treated between March 2006 and June 2012 by using transarterial Onyx embolization with intent to cure. The mean age was 57 years; one-third presented with intracranial hemorrhage. Most (85%) had cortical venous drainage. Once angiographic cure was achieved, long-term treatment effectiveness was assessed with DSA and clinical follow-up. Forty-nine embolization sessions were performed; 85% of cranial dural arteriovenous fistulas were treated in a single session. The immediate angiographic cure rate was 95%. The permanent neurologic complication rate was 2% (mild facial palsy). Thirty-five of the 38 patients with initial cure underwent short-term follow-up DSA (median, 4 months). The short-term recurrence rate was only 6% (2/35). All patients with occlusion at short-term DSA undergoing long-term DSA (median, 28 months) had durable occlusion. No patient with long-term clinical follow-up (total, 117 patient-years; median, 45 months) experienced hemorrhage. Transarterial embolization with Onyx as the single embolic agent results in durable long-term cure of noncavernous cranial dural arteriovenous fistulas. Recurrence rates are low on short-term follow-up, and all patients with angiographic occlusion on short-term DSA follow-up have experienced a durable long-term cure. Thus, angiographic cure should be defined at short-term follow-up angiography instead of at the end of the final embolization session. Finally, long-term DSA follow-up may not be necessary if occlusion is demonstrated on short-term angiographic follow-up. © 2014 by American Journal of Neuroradiology.

[Digital angiography and lipiodol computerized tomography in the anatomopathological framework of hepatocarcinoma].

PubMed

Pozzi-Mucelli, R; Pozzi-Mucelli, R; Pagnan, L; Dalla Palma, L

1994-12-01

The introduction of therapies other than conventional surgery of hepatocellular carcinoma (HCC) requires an accurate pathologic classification, which is important because it is well known that HCC may have multicentric growth. The Liver Cancer Study Group of Japan has proposed a classification dividing HCCs into three macroscopic forms from the pathologic point of view: nodular, massive and infiltrating HCCs. The nodular type is subdivided into four types: single nodular type, single nodular type with surrounding proliferation, multinodular fused type and multinodular type. Forty-six HCC patients were examined with Lipiodol Computed Tomography (LCT) to investigate the agreement between pathologic and imaging findings. LCT proved to be in close agreement with pathologic findings. Sixteen cases were classified as type I (single nodular type), 8 as type II (single nodular type with limited foci), 1 as type III (multinodular fused type), 18 as type IV (multiple nodular type with diffuse foci) and 3 cases as type V (massive form). No cases of infiltrative forms were observed in our series. Based on LCT findings, the capabilities of digital subtraction angiography (DSA) were studied in the pathologic classification of HCCs. DSA exhibited some limitations in the pathologic classification of HCCs in 5 of 16 patients with type I lesions. In these cases DSA suggested false-positive diagnoses because of regenerative nodules in cirrhotic liver in 3 cases and of daughter nodules (not confirmed at LCT) in 2 cases. In 7 of 8 patients with type II HCCs, DSA failed to show the daughter nodules surrounding the main nodule. In the 18 patients with multiple distant nodules (type IV), DSA was less sensitive in defining nodule number and site. In the massive form, the information obtained with LCT and DSA was comparable. In conclusion, LCT should be considered a basic examination in the study of HCC extent. Based on LCT findings, the most appropriate treatment can be selected, be it surgery, alcohol injection, or intraarterial chemoembolization.

Nickel-based anode with water storage capability to mitigate carbon deposition for direct ethanol solid oxide fuel cells.

PubMed

Wang, Wei; Su, Chao; Ran, Ran; Zhao, Bote; Shao, Zongping; Tade, Moses O; Liu, Shaomin

2014-06-01

The potential to use ethanol as a fuel places solid oxide fuel cells (SOFCs) as a sustainable technology for clean energy delivery because of the renewable features of ethanol versus hydrogen. In this work, we developed a new class of anode catalyst exemplified by Ni+BaZr0.4Ce0.4Y0.2O3 (Ni+BZCY) with a water storage capability to overcome the persistent problem of carbon deposition. Ni+BZCY performed very well in catalytic efficiency, water storage capability and coking resistance tests. A stable and high power output was well maintained with a peak power density of 750 mW cm(-2) at 750 °C. The SOFC with the new robust anode performed for seven days without any sign of performance decay, whereas SOFCs with conventional anodes failed in less than 2 h because of significant carbon deposition. Our findings indicate the potential applications of these water storage cermets as catalysts in hydrocarbon reforming and as anodes for SOFCs that operate directly on hydrocarbons. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flexible interfaces between Si anodes and composite electrolytes consisting of poly(propylene carbonates) and garnets for solid-state batteries

NASA Astrophysics Data System (ADS)

Huo, Hanyu; Sun, Jiyang; chen, Cheng; Meng, Xianglu; He, Minghui; Zhao, Ning; Guo, Xiangxin

2018-04-01

Flexible interfaces between Si anodes and composite electrolytes consisting of poly(propylene carbonates) (PPCs) and garnets have been fabricated. The solid polymer electrolytes (SPEs) of PPC/garnet/LiTFSI show the conductivity of 4.2 × 10-4 S cm-1 at room temperature. Their combination with the Si layer anodes allows great alleviation of internal stress resulting from the large volume variation during lithiation and delithiation process of Si anodes. As a result, the Si/SPE/Li cells exhibit 2520 mAh g-1, 2260 mAh g-1, 1902 mAh g-1, 1342 mAh g-1 at 0.1 C, 0.2 C, 0.5 C, and 1 C, respectively. Furthermore, with such compatible and stable interfaces of Si/SPE and the LiFePO4 cathodes in solid-state batteries, the specific capacity of 2296 mAh g-1 in terms of Si is obtained, which remains 82.6% after 100 cycles at room temperature and 0.1 C. The results here indicate that constructing of flexible interfaces between Si anodes and SPEs is a promising strategy to develop high performance solid-state batteries.

Increase in the neutron yield from a dense plasma-focus experiment performed with a conical tip placed in the centre of the anode end

NASA Astrophysics Data System (ADS)

Kubes, P.; Paduch, M.; Cikhardt, J.; Cikhardtova, B.; Klir, D.; Kravarik, J.; Rezac, K.; Zielinska, E.; Sadowski, M. J.; Szymaszek, A.; Tomaszewski, K.; Zaloga, D.

2017-09-01

The paper describes the evolution of self-organized structures inside a pinched plasma column during the phase of the effective production of fusion neutrons, as observed in the mega-ampere plasma focus experiment performed with a conical tip placed in the centre of the anode face. In a comparison with the plane anode face configuration, the described anode shape facilitated transformations in the pinch column during the neutron production and increased the neutron yield several times. Simultaneously, it decreased the minimal diameter and the length of the pinched column, and it depressed the first neutron pulse. It also induced shorter pulses of X-rays and neutrons, which enabled the determination of a temporal difference between the emission of electron and deuteron beams. The fast electrons were produced mainly during a disruption of the pinch constriction, while the fast deuterons - during the formation and explosion of plasmoids. The paper also presents the temporal evolution of a current distribution in the plasmoid during the neutron production, as well as the appearance and stable positions of current filaments traces upon the surface of the conical anode tip.

Mesoporous Germanium Anode Materials for Lithium-Ion Battery with Exceptional Cycling Stability in Wide Temperature Range.

PubMed

Choi, Sinho; Cho, Yoon-Gyo; Kim, Jieun; Choi, Nam-Soon; Song, Hyun-Kon; Wang, Guoxiu; Park, Soojin

2017-04-01

Porous structured materials have unique architectures and are promising for lithium-ion batteries to enhance performances. In particular, mesoporous materials have many advantages including a high surface area and large void spaces which can increase reactivity and accessibility of lithium ions. This study reports a synthesis of newly developed mesoporous germanium (Ge) particles prepared by a zincothermic reduction at a mild temperature for high performance lithium-ion batteries which can operate in a wide temperature range. The optimized Ge battery anodes with the mesoporous structure exhibit outstanding electrochemical properties in a wide temperature ranging from -20 to 60 °C. Ge anodes exhibit a stable cycling retention at various temperatures (capacity retention of 99% after 100 cycles at 25 °C, 84% after 300 cycles at 60 °C, and 50% after 50 cycles at -20 °C). Furthermore, full cells consisting of the mesoporous Ge anode and an LiFePO 4 cathode show an excellent cyclability at -20 and 25 °C. Mesoporous Ge materials synthesized by the zincothermic reduction can be potentially applied as high performance anode materials for practical lithium-ion batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Intravascular flow detection during transforaminal epidural injections: a prospective assessment.

PubMed

El Abd, Omar Hamman; Amadera, Joao Eduardo Daud; Pimentel, Daniel Camargo; Pimentel, Thais Spacov Camargo

2014-01-01

Transforaminal epidural steroid injections (TFESI) are a mainstay in the treatment of spine pain. Though this commonly performed procedure is generally felt to be safe, devastating complications following inadvertent intra-arterial injections of particulate steroid have been reported. The use of digital subtraction angiography (DSA) has been suggested as a means of detecting intra-arterial needle placements prior to medication injection. To examine the efficacy of DSA in detecting intra-arterial needle placements during TFESI. Prospective cohort study evaluating the impact of DSA on detecting intra-arterial needle placements during TFESI. We enrolled 150 consecutive patients presenting to a university-affiliated spine center with discogenic and/or radicular symptoms affecting the cervical, lumbar, and sacral regions. For each injection, prior to imaging with DSA, traditional methods for vascular penetration detection were employed, including the identification of blood in the needle hub (flash), negative aspiration of blood prior to injection, and live fluoroscopic injection of contrast. Once these tests were performed and negative for signs of intra-arterial needle placement, DSA imaging was utilized prior to medication administration for identification of vascular flow. A total number of 222 TFESI were performed, 41 injections at the cervical levels (18.47%), 113 at the lumbar levels (50.9%), and 68 at the sacral levels (30.36%). Flash was observed in 13 injections performed (5.85% of the total number of injections): one (0.45%) in the cervical, 2 (0.9%) in the lumbar, and 10 (4.5%) in the sacral levels. In 11 TFESI blood aspiration was obtained (4.95% of all injections): 3 (1.3%) in cervical, 4 (1.8%) in lumbar, and 4 (1.8%) in sacral injections. Live fluoroscopy during contrast injection detected 46 (20.72%) intravascular flow patterns: 7 (3.1%) cervical, 17 (7.6%) lumbar, and 22 (9.9%) sacral. DSA identified an additional 5 intravascular injections after all previous steps had resulted in negative vascular penetration signs, which accounted for 2.25% of all injections. This is a prospective, single-center study with a relatively small number of patients and no control group. DSA detected additional 5.26% intravascular needle placements following traditional methods. Our findings also support other studies that conclude TFESI are generally a safe procedure. We recommend that special attention should be paid to the sacral injections as vascular penetration was statistically higher than at other levels.

Structures, phase stabilities, and electrical potentials of Li-Si battery anode materials

NASA Astrophysics Data System (ADS)

Tipton, William W.; Bealing, Clive R.; Mathew, Kiran; Hennig, Richard G.

2013-05-01

The Li-Si materials system holds promise for use as an anode in Li-ion battery applications. For this system, we determine the charge capacity, voltage profiles, and energy storage density solely by ab initio methods without any experimental input. We determine the energetics of the stable and metastable Li-Si phases likely to form during the charging and discharging of a battery. Ab initio molecular dynamics simulations are used to model the structure of amorphous Li-Si as a function of composition, and a genetic algorithm coupled to density-functional theory searches the Li-Si binary phase diagram for small-cell, metastable crystal structures. Calculations of the phonon densities of states using density-functional perturbation theory for selected structures determine the importance of vibrational, including zero-point, contributions to the free energies. The energetics and local structural motifs of these metastable Li-Si phases closely resemble those of the amorphous phases, making these small unit cell crystal phases good approximants of the amorphous phase for use in further studies. The charge capacity is estimated, and the electrical potential profiles and the energy density of Li-Si anodes are predicted. We find, in good agreement with experimental measurements, that the formation of amorphous Li-Si only slightly increases the anode potential. Additionally, the genetic algorithm identifies a previously unreported member of the Li-Si binary phase diagram with composition Li5Si2 which is stable at 0 K with respect to previously known phases. We discuss its relationship to the partially occupied Li7Si3 phase.

Aqueous Binder Enhanced High-Performance GeP5 Anode for Lithium-Ion Batteries

PubMed Central

He, Jun; Wei, Yaqing; Hu, Lintong; Li, Huiqiao; Zhai, Tianyou

2018-01-01

GeP5 is a recently reported new anode material for lithium ion batteries (LIBs), it holds a large theoretical capacity about 2300 mAh g−1, and a high rate capability due to its bi-active components and superior conductivity. However, it undergoes a large volume change during its electrochemical alloying and de-alloying with Li, a suitable binder is necessary to stable the electrode integrity for improving cycle performance. In this work, we tried to apply aqueous binders LiPAA and NaCMC to GeP5 anode, and compared the difference in electrochemical performance between them and traditional binder PVDF. As can be seen from the test result, GeP5 can keep stable in both common organic solvents and proton solvents such as water and alcohol solvents, it meets the application requirements of aqueous binders. The electrochemistry results show that the use of LiPAA binder can significantly improve the initial Coulombic efficiency, reversible capacity, and cyclability of GeP5 anode as compared to the electrodes based on NaCMC and PVDF binders. The enhanced electrochemical performance of GeP5 electrode with LiPAA binder can be ascribed to the unique high strength long chain polymer structure of LiPAA, which also provide numerous uniform distributed carboxyl groups to form strong ester groups with active materials and copper current collector. Benefit from that, the GeP5 electrode with LiPAA can also exhibit excellent rate capability, and even at low temperature, it still shows attractive electrochemical performance. PMID:29484292

Aqueous Binder Enhanced High-Performance GeP5 Anode for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

He, Jun; Wei, Yaqing; Hu, Lintong; Li, Huiqiao; Zhai, Tianyou

2018-02-01

GeP5 is a recently reported new anode material for lithium ion batteries (LIBs), it holds a large theoretical capacity about 2300 mAh g-1, and a high rate capability due to its bi-active components and superior conductivity. However, it undergoes a large volume change during its electrochemical alloying and de-alloying with Li, a suitable binder is necessary to stable the electrode integrity for improving cycle performance. In this work, we tried to apply aqueous binders LiPAA and NaCMC to GeP5 anode, and compared the difference in electrochemical performance between them and traditional binder PVDF. As can be seen from the test result, GeP5 can keep stable in both common organic solvents and proton solvents such as water and alcohol solvents, it meets the application requirements of aqueous binders. The electrochemistry results show that the use of LiPAA binder can significantly improve the initial Coulombic efficiency, reversible capacity, and cyclability of GeP5 anode as compared to the electrodes based on NaCMC and PVDF binders. The enhanced electrochemical performance of GeP5 electrode with LiPAA binder can be ascribed to the unique high strength long chain polymer structure of LiPAA, which also provide numerous uniform distributed carboxyl groups to form strong ester groups with active meterials and copper current collector. Benefit from that, the GeP5 electrode with LiPAA can also exhibit excellent rate capability, and even at low temperature, it still shows attractive electrochemical performance.

Theoretical study of a consumable anode in a gas metal welding arc

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, P.; Simpson, S.W.

1996-12-31

A better understanding of the behavior of the metal transfer process in a welding arc is important for further improvement of quality control for gas-metal-arc welding (GMAW). The problems related to the metal transfer are generally complicated because (a) the metal transfer process is strongly coupled with the arc plasma, which is not stable, for example, the length of the arc plasma varies during the formation and detachment of a metal droplet, and (b) the formation of the electrode droplet itself is influenced by energy transfer, the anode-plasma interface, and also the location of the liquid-solid interface inside the anode.more » This paper presents primary results of an investigation of the consumable anode in a gas metal welding arc. The study includes theoretical predictions of the properties related to metal transfer including moving anode temperature profile, welding arc length and arc current as a function of time for various wire feed rates, as well as numerical treatment of droplet formation. The anode temperature profile and the melting rate are analyzed by a metal transfer model which couples a two-dimensional arc model to a one-dimensional anode thermal model. The droplet formation is predicted by a quasi-one-dimensional dynamic model of a pendant drop which accounts for the electromagnet pinch effect, the surface tension, gravitation and the momentum transfer due to wire motion. Comparison between experimental observation and theoretical predictions will also be discussed.« less

Thermal cycling and electrochemical characteristics of solid oxide fuel cell supported on stainless steel with a new 3-phase composite anode

NASA Astrophysics Data System (ADS)

Dayaghi, Amir Masoud; Kim, Kun Joong; Kim, Sun Jae; Kim, Sunwoong; Bae, Hongyeul; Choi, Gyeong Man

2017-06-01

We report design, fabrication method, and fast thermal-cycling ability of solid oxide fuel cells (SOFCs) that use stainless steel (STS) as a support, and a new 3-phase anode. La and Ni co-doped SrTiO3 (La0.2Sr0.8Ti0.9Ni0.1O3-d, LSTN), replaces some of the Ni in conventional Ni-yttria stabilized zirconia (YSZ) anode; the resultant LSTN-YSZ-Ni 3-phase-composite anode is tested as a new reduction (or decomposition)-resistant anode of STS-supported SOFCs that can be co-fired with STS. A multi-layered cell with YSZ electrolyte (thickness ∼5 μm), composite anode, STS-cermet contact-layer, and STS support is designed, then fabricated by tape casting, lamination, and co-firing at 1250 °C in reducing atmosphere. The maximum power density (MPD) is 325 mW cm-2 at 650 °C; this is one of the highest among STS-supported cells fabricated by co-firing. The cell also shows stable open-circuit voltage and Ohmic resistance during 100 rapid thermal cycles between 170 and 600 °C. STS support minimizes stress and avoids cracking of electrolyte during rapid thermal cycling. The excellent MPD and stability during thermal cycles, and promising characteristics of SOFC as a power source for vehicle or mobile devices that requires rapid thermal cycles, are attributed to the new design of the cell with new anode structure.

Enhancing Sulfur Tolerance of Ni-Based Cermet Anodes of Solid Oxide Fuel Cells by Ytterbium-Doped Barium Cerate Infiltration.

PubMed

Li, Meng; Hua, Bin; Luo, Jing-Li; Jiang, San Ping; Pu, Jian; Chi, Bo; Li, Jian

2016-04-27

Conventional anode materials for solid oxide fuel cells (SOFCs) are Ni-based cermets, which are highly susceptible to deactivation by contaminants in hydrocarbon fuels. Hydrogen sulfide is one of the commonly existed contaminants in readily available natural gas and gasification product gases of pyrolysis of biomasses. Development of sulfur tolerant anode materials is thus one of the critical challenges for commercial viability and practical application of SOFC technologies. Here we report a viable approach to enhance substantially the sulfur poisoning resistance of a Ni-gadolinia-doped ceria (Ni-GDC) anode through impregnation of proton conducting perovskite BaCe0.9Yb0.1O3-δ (BCYb). The impregnation of BCYb nanoparticles improves the electrochemical performance of the Ni-GDC anode in both H2 and H2S containing fuels. Moreover, more importantly, the enhanced stability is observed in 500 ppm of H2S/H2. The SEM and XPS analysis indicate that the infiltrated BCYb fine particles inhibit the adsorption of sulfur and facilitate sulfur removal from active sites, thus preventing the detrimental interaction between sulfur and Ni-GDC and the formation of cerium sulfide. The preliminary results of the cell with the BCYb+Ni-GDC anode in methane fuel containing 5000 ppm of H2S show the promising potential of the BCYb infiltration approach in the development of highly active and stable Ni-GDC-based anodes fed with hydrocarbon fuels containing a high concentration of sulfur compounds.

Solution of the within-group multidimensional discrete ordinates transport equations on massively parallel architectures

NASA Astrophysics Data System (ADS)

Zerr, Robert Joseph

2011-12-01

The integral transport matrix method (ITMM) has been used as the kernel of new parallel solution methods for the discrete ordinates approximation of the within-group neutron transport equation. The ITMM abandons the repetitive mesh sweeps of the traditional source iterations (SI) scheme in favor of constructing stored operators that account for the direct coupling factors among all the cells and between the cells and boundary surfaces. The main goals of this work were to develop the algorithms that construct these operators and employ them in the solution process, determine the most suitable way to parallelize the entire procedure, and evaluate the behavior and performance of the developed methods for increasing number of processes. This project compares the effectiveness of the ITMM with the SI scheme parallelized with the Koch-Baker-Alcouffe (KBA) method. The primary parallel solution method involves a decomposition of the domain into smaller spatial sub-domains, each with their own transport matrices, and coupled together via interface boundary angular fluxes. Each sub-domain has its own set of ITMM operators and represents an independent transport problem. Multiple iterative parallel solution methods have investigated, including parallel block Jacobi (PBJ), parallel red/black Gauss-Seidel (PGS), and parallel GMRES (PGMRES). The fastest observed parallel solution method, PGS, was used in a weak scaling comparison with the PARTISN code. Compared to the state-of-the-art SI-KBA with diffusion synthetic acceleration (DSA), this new method without acceleration/preconditioning is not competitive for any problem parameters considered. The best comparisons occur for problems that are difficult for SI DSA, namely highly scattering and optically thick. SI DSA execution time curves are generally steeper than the PGS ones. However, until further testing is performed it cannot be concluded that SI DSA does not outperform the ITMM with PGS even on several thousand or tens of thousands of processors. The PGS method does outperform SI DSA for the periodic heterogeneous layers (PHL) configuration problems. Although this demonstrates a relative strength/weakness between the two methods, the practicality of these problems is much less, further limiting instances where it would be beneficial to select ITMM over SI DSA. The results strongly indicate a need for a robust, stable, and efficient acceleration method (or preconditioner for PGMRES). The spatial multigrid (SMG) method is currently incomplete in that it does not work for all cases considered and does not effectively improve the convergence rate for all values of scattering ratio c or cell dimension h. Nevertheless, it does display the desired trend for highly scattering, optically thin problems. That is, it tends to lower the rate of growth of number of iterations with increasing number of processes, P, while not increasing the number of additional operations per iteration to the extent that the total execution time of the rapidly converging accelerated iterations exceeds that of the slower unaccelerated iterations. A predictive parallel performance model has been developed for the PBJ method. Timing tests were performed such that trend lines could be fitted to the data for the different components and used to estimate the execution times. Applied to the weak scaling results, the model notably underestimates construction time, but combined with a slight overestimation in iterative solution time, the model predicts total execution time very well for large P. It also does a decent job with the strong scaling results, closely predicting the construction time and time per iteration, especially as P increases. Although not shown to be competitive up to 1,024 processing elements with the current state of the art, the parallelized ITMM exhibits promising scaling trends. Ultimately, compared to the KBA method, the parallelized ITMM may be found to be a very attractive option for transport calculations spatially decomposed over several tens of thousands of processes. Acceleration/preconditioning of the parallelized ITMM once developed will improve the convergence rate and improve its competitiveness. (Abstract shortened by UMI.)

Electrolyte Chemistry for Simultaneous Stabilization of Potassium Metal and Superoxide in K-O₂ Batteries.

PubMed

Xiao, Neng; Gourdin, Gerald; Wu, Yiying

2018-05-22

In the superoxide batteries based on O2/O2- redox chemistry, identifying an electrolyte to stabilize both alkali metal and superoxide remains challenging due to their reactivity towards electrolyte components. Bis(fluorosulfonyl)imide (FSI-) has been recognized as a "magical anion" for passivating alkali metals. Herein, we illustrate the chemical reactions between FSI- and superoxide, and the resultant dilemma when considering an anode-compatible electrolyte vs. a cathode-compatible one in K-O2 batteries. On one side, the KFSI-dimethoxyethane (DME) electrolyte passivates the potassium metal anode via the cleavage of S-F bond and formation of a KF-rich solid electrolyte interface (SEI). Nevertheless, the KFSI salt is chemically unstable due to the nucleophilic attack by superoxide and/or hydroxide species. On the other hand, potassium bis(trifluorosulfonyl)imide (KTFSI) is stable for KO2, but results in mossy deposition and irreversible plating and stripping. In order to circumvent this dilemma, we develop an artificial SEI for K metal anode to achieve long cycle-life K-O2 batteries. This work contributes to the understanding of electrolyte chemistry and guides the development of stable electrolytes and artificial SEI in metal-O2 batteries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crack-resistant polyimide coating for high-capacity battery anodes

NASA Astrophysics Data System (ADS)

Li, Yingshun; Wang, Shuo; Lee, Pui-Kit; He, Jieqing; Yu, Denis Y. W.

2017-10-01

Electrode cracking is a serious problem that hinders the application of many next-generation high-capacity anode materials for lithium-ion batteries. Even though nano-sizing the material can reduce fracturing of individual particles, capacity fading is still observed due to large volume change and loss of contact in the electrode during lithium insertion and extraction. In this study, we design a crack-resistant high-modulus polyimide coating with high compressive strength which can hold multiple particles together during charge and discharge to maintain contact. The effectiveness of the coating is demonstrated on tin dioxide, a high-capacity large-volume-change material that undergoes both alloy and conversion reactions. The polyimide coating improves capacity retention of SnO2 from 80% to 100% after 80 cycles at 250 mA g-1. Stable capacity of 585 mAh g-1 can be obtained even at 500 mA g-1 after 300 cycles. Scanning electron microscopy and in-situ dilatometry confirm that electrode cracking is suppressed and thickness change is reduced with the coating. In addition, the chemically-stable polyimide film can separate the surface from direct contact with electrolyte, improving coulombic efficiency to ∼100%. We expect the novel strategy of suppressing electrode degradation with a crack-resistant coating can also be used for other alloy and conversion-based anodes.

A rechargeable Li-O2 battery using a lithium nitrate/N,N-dimethylacetamide electrolyte.

PubMed

Walker, Wesley; Giordani, Vincent; Uddin, Jasim; Bryantsev, Vyacheslav S; Chase, Gregory V; Addison, Dan

2013-02-13

A major challenge in the development of rechargeable Li-O(2) batteries is the identification of electrolyte materials that are stable in the operating environment of the O(2) electrode. Straight-chain alkyl amides are one of the few classes of polar, aprotic solvents that resist chemical degradation in the O(2) electrode, but these solvents do not form a stable solid-electrolyte interphase (SEI) on the Li anode. The lack of a persistent SEI leads to rapid and sustained solvent decomposition in the presence of Li metal. In this work, we demonstrate for the first time successful cycling of a Li anode in the presence of the solvent, N,N-dimethylacetamide (DMA), by employing a salt, lithium nitrate (LiNO(3)), that stabilizes the SEI. A Li-O(2) cell containing this electrolyte composition is shown to cycle for more than 2000 h (>80 cycles) at a current density of 0.1 mA/cm(2) with a consistent charging profile, good capacity retention, and O(2) detected as the primary gaseous product formed during charging. The discovery of an electrolyte system that is compatible with both electrodes in a Li-O(2) cell may eliminate the need for protecting the anode with a ceramic membrane.

Another Piece of the Antibody Puzzle: Observations from the HALT study\\.

PubMed

Snyder, Laurie D; Tinckam, Kathryn J

2018-06-04

In the rapidly evolving domain of clinical transplantation immunobiology, the interrogation and interpretation of HLA antibodies and their associated clinical consequences are in the spotlight. In lung transplant, HLA antibodies, in particular donor specific antibodies (DSA), are a determining component of the lung transplant antibody mediated rejection (AMR) definition (1). DSA after lung transplant are widely regarded as poor prognosticator, though sparse data to date necessitate ongoing discourse and continued investigation into incidence, timing and treatment. Prior studies reported a wide range of DSA incidence with differing consequences on a background of highly variable timing, methods, antibody analytic strategies and clinical definitions. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Fourier mode analysis of slab-geometry transport iterations in spatially periodic media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larsen, E; Zika, M

1999-04-01

We describe a Fourier analysis of the diffusion-synthetic acceleration (DSA) and transport-synthetic acceleration (TSA) iteration schemes for a spatially periodic, but otherwise arbitrarily heterogeneous, medium. Both DSA and TSA converge more slowly in a heterogeneous medium than in a homogeneous medium composed of the volume-averaged scattering ratio. In the limit of a homogeneous medium, our heterogeneous analysis contains eigenvalues of multiplicity two at ''resonant'' wave numbers. In the presence of material heterogeneities, error modes corresponding to these resonant wave numbers are ''excited'' more than other error modes. For DSA and TSA, the iteration spectral radius may occur at these resonantmore » wave numbers, in which case the material heterogeneities most strongly affect iterative performance.« less

Fabrication of cellulose/graphene paper as a stable-cycling anode materials without collector.

PubMed

Zhang, Chunliang; Cha, Ruitao; Yang, Luming; Mou, Kaiwen; Jiang, Xingyu

2018-03-15

Flexible and foldable devices attract substantial attention in low-cost electronics. Among the flexible substrate materials, paper has several attractive advantages. In our study, we fabricate cellulose/graphene paper by wet end formation (papermaking). The cationic polyacrylamide remarkably improve the retention ratio of graphene of cellulose/graphene slurry. Besides, cellulose/graphene paper exhibits well mechanical properties such as its flexibility and folding endurance. And we replace copper foil collector with cellulose/graphene paper in lithium-ion batteries without collector, and investigate its electrochemical properties. The obtained results show that cellulose/graphene paper presents excellent charge-discharge stability after 1600th cycles as the anode of lithium-ion batteries. These advantages highlight the potential applications of cellulose/graphene paper as anode materials for lithium-ion batteries. Copyright © 2017 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Ruiguo; Mishra, Kuber; Li, Xiaolin

Rechargeable batteries based upon sodium (Na+) cations are at the core of many new battery chemistries beyond Li-ion batteries. Rather than using carbon or alloy-based anodes, the direct utilization of solid sodium metal as an anode would be highly advantageous, but its use has been highly problematic due to its high reactivity. In this work, however, it is demonstrated that, by tailoring the electrolyte formulation, solid Na metal can be electrochemically plated/stripped at ambient temperature with high efficiency (> 99%) on both copper and inexpensive aluminum current collectors thereby enabling a shift in focus to new battery chemical couples basedmore » upon Na metal operating at ambient temperature. These highly concentrated electrolytes has enabled stable cycling of Na metal batteries based on a Na metal anode and Na3V2(PO4)3 cathode at high rates with very high efficiency.« less

Uniform Li deposition regulated via three-dimensional polyvinyl alcohol nanofiber networks for effective Li metal anodes.

PubMed

Wang, Gang; Xiong, Xunhui; Lin, Zhihua; Zheng, Jie; Fenghua, Zheng; Li, Youpeng; Liu, Yanzhen; Yang, Chenghao; Tang, Yiwei; Liu, Meilin

2018-05-31

Lithium metal anodes are considered to be the most promising anode material for next-generation advanced energy storage devices due to their high reversible capacity and extremely low anode potential. Nevertheless, the formation of dendritic Li, induced by the repeated breaking and repairing of solid electrolyte interphase layers, always causes poor cycling performance and low coulombic efficiency, as well as serious safety problems, which have hindered the practical application of Li anodes for a long time. Herein, we design an electrode by covering a polyvinyl alcohol layer with a three-dimensional nanofiber network structure through an electrospinning technique. The polar functional groups on the surface of the polymer nanofibers can restrict the deposition of Li along the fibers and regulate the deposition of Li uniformly in the voids between the nanofibers. Owing to the structural features of the polymer, the modified Li|Cu electrode displays excellent cycle stability, with a high coulombic efficiency of 98.6% after 200 cycles at a current density of 1 mA cm-2 under a deposition capacity of 1 mA h cm-2, whilst the symmetric cell using the polymer modified Li anode shows stable cycling with a low hysteresis voltage of ∼80 mV over 600 h at a current density of 5 mA cm-2.

Porous Ni-Fe alloys as anode support for intermediate temperature solid oxide fuel cells: I. Fabrication, redox and thermal behaviors

NASA Astrophysics Data System (ADS)

Wang, Xin; Li, Kai; Jia, Lichao; Zhang, Qian; Jiang, San Ping; Chi, Bo; Pu, Jian; Jian, Li; Yan, Dong

2015-03-01

Porous Ni-Fe anode supports for intermediate solid oxide fuel cells are prepared by reducing the sintered NiO-(0-50 wt. %) Fe2O3 composites in H2, their microstructure, redox and thermal expansion/cycling characteristics are systematically investigated. The sintered NiO-Fe2O3 composites are consisted of NiO and NiFe2O4, and are fully reducible to porous metallic Ni-Fe alloys in H2 at temperatures between 600 and 750 °C. The porous structure contains pores in bimodal distribution with larger pores between the sintered particles and smaller ones inside the particles. The oxidation resistance of the Ni-Fe alloy anode supports at 600 and 750 °C is increased by the addition of Fe, their oxidation kinetics obeys a multistage parabolic law in the form of (Percentageweightgain /Specificsurfacearea) 2 =kp · t , where kp is the rate constant and t the oxidation time. The dimension of the Ni-Fe anode supports is slightly changed without disintegrating their structure, and Fe addition is beneficial to the redox stability. The TEC of the Ni-Fe alloy anode supports decreases with the increase of Fe content. The anode supports containing Fe is less stable in dimension during thermal cycles due to the continuous sintering, but the dimension change after thermal cycles is within 1%.

Effects of carbon brush anode size and loading on microbial fuel cell performance in batch and continuous mode

NASA Astrophysics Data System (ADS)

Lanas, Vanessa; Ahn, Yongtae; Logan, Bruce E.

2014-02-01

Larger scale microbial fuel cells (MFCs) require compact architectures to efficiently treat wastewater. We examined how anode-brush diameter, number of anodes, and electrode spacing affected the performance of the MFCs operated in fed-batch and continuous flow mode. All anodes were initially tested with the brush core set at the same distance from the cathode. In fed-batch mode, the configuration with three larger brushes (25 mm diameter) produced 80% more power (1240 mW m-2) than reactors with eight smaller brushes (8 mm) (690 mW m-2). The higher power production by the larger brushes was due to more negative and stable anode potentials than the smaller brushes. The same general result was obtained in continuous flow operation, although power densities were reduced. However, by moving the center of the smaller brushes closer to the cathode (from 16.5 to 8 mm), power substantially increased from 690 to 1030 mW m-2 in fed batch mode. In continuous flow mode, power increased from 280 to 1020 mW m-2, resulting in more power production from the smaller brushes than the larger brushes (540 mW m-2). These results show that multi-electrode MFCs can be optimized by selecting smaller anodes, placed as close as possible to the cathode.

Isolated v-lesion represents a benign phenotype of vascular rejection of the kidney allograft- a retrospective study.

PubMed

Novotny, Marek; Hruba, Petra; Vichova, Petra; Maluskova, Jana; Honsova, Eva; Viklicky, Ondrej; Wohlfahrtova, Mariana

2018-05-31

While the detrimental impact of the humoral acute vascular rejection (AVR) phenotype is recognized, the prognostic significance of isolated v-lesion (IV) remains unclear. In this retrospective single-centre study, AVR was found in 98 out of 1015 patients (9.7%) who had undergone kidney transplantation in 2010-2014, with donor-specific antibodies (DSA) evaluated in all of them. The outcome of four AVR phenotypes was evaluated during median follow-up of 59 months; in 25 patients with IV, 18 with T cell-mediated vascular rejection (TCMRV), 19 with antibody-mediated vascular rejection (AMRV) and 36 with suspected antibody-mediated rejection (sAMRV). AVR was diagnosed mainly by for-cause biopsy (81%) early after transplantation (median 19 POD) and appeared as mild grade intimal arteritis. IV occurred in low sensitized patients after the first transplantation (96%) in the absence of DSA. IV responded satisfactorily to treatment (88%), showed no persistence of rejection in surveillance biopsy, had stable graft function, minimal proteinuria and excellent DCGS (96%). Contrary to that, Kaplan-Meier estimate of 3-year DCGS of AMRV was 66% (log rank=0.0004). Early IV represents a benign phenotype of AVR with a favourable outcome. This study prompts further research to evaluate the nature of IV before considering any change in the classification and management. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Non-Enhanced MR Imaging of Cerebral Arteriovenous Malformations at 7 Tesla.

PubMed

Wrede, Karsten H; Dammann, Philipp; Johst, Sören; Mönninghoff, Christoph; Schlamann, Marc; Maderwald, Stefan; Sandalcioglu, I Erol; Ladd, Mark E; Forsting, Michael; Sure, Ulrich; Umutlu, Lale

2016-03-01

To evaluate prospectively 7 Tesla time-of-flight (TOF) magnetic resonance angiography (MRA) and 7 Tesla non-contrast-enhanced magnetization-prepared rapid acquisition gradient-echo (MPRAGE) for delineation of intracerebral arteriovenous malformations (AVMs) in comparison to 1.5 Tesla TOF MRA and digital subtraction angiography (DSA). Twenty patients with single or multifocal AVMs were enrolled in this trial. The study protocol comprised 1.5 and 7 Tesla TOF MRA and 7 Tesla non-contrast-enhanced MPRAGE sequences. All patients underwent an additional four-vessel 3D DSA. Image analysis of the following five AVM features was performed individually by two radiologists on a five-point scale: nidus, feeder(s), draining vein(s), relationship to adjacent vessels, and overall image quality and presence of artefacts. A total of 21 intracerebral AVMs were detected. Both sequences at 7 Tesla were rated superior over 1.5 Tesla TOF MRA in the assessment of all considered AVM features. Image quality at 7 Tesla was comparable with DSA considering both sequences. Inter-observer accordance was good to excellent for the majority of ratings. This study demonstrates excellent image quality for depiction of intracerebral AVMs using non-contrast-enhanced 7 Tesla MRA, comparable with DSA. Assessment of untreated AVMs is a promising clinical application of ultra-high-field MRA. • Non-contrast-enhanced 7 Tesla MRA demonstrates excellent image quality for intracerebral AVM depiction. • Image quality at 7 Tesla was comparable with DSA considering both sequences. • Assessment of intracerebral AVMs is a promising clinical application of ultra-high-field MRA.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jens, Sjoerd, E-mail: s.jens@amc.uva.nl; Lucatelli, Pierleone, E-mail: pierleone.lucatelli@gmail.com; Koelemay, Mark J. W., E-mail: m.j.koelemaij@amc.uva.nl

Purpose. To evaluate the additional value of three-dimensional rotational angiography (3DRA) of the foot compared with digital subtraction angiography (DSA) in patients with critical limb ischemia (CLI). Technique. For 3DRA, the C-arm was placed in the propeller position with the foot in an isocentric position. The patient's unaffected foot was positioned in a footrest outside the field of view. For correct timing of 3DRA, the delay from contrast injection in the popliteal artery at the level of knee joint to complete pedal arterial enhancement was assessed using DSA. With this delay, 3DRA was started after injection of 15 ml contrast.more » Imaging of the 3DRA could directly be reconstructed and visualized.Materials and MethodsPatients undergoing 3DRA of the foot were prospectively registered. DSA and 3DRA images were scored separately for arterial patency and presence of collaterals. Treatment strategies were proposed based on DSA with and without the availability of 3DRA. Results. Eleven patients underwent 3DRA of the foot. One 3DRA was not included because the acquisition was focused on the heel instead of the entire foot. Diagnostic quality of 3DRA was good in all ten patients. 3DRA compared with DSA showed additional patent arteries in six patients, patent plantar arch in three patients, and collaterals between the pedal arteries in five patients. Additional information from 3DRA resulted in a change of treatment strategy in six patients. Conclusion, 3DRA of the foot contains valuable additional real-time information to better guide peripheral vascular interventions in patients with CLI and nonhealing tissue lesions.« less

The detection of NBOMe designer drugs on blotter paper by high resolution time-of-flight mass spectrometry (TOFMS) with and without chromatography.

PubMed

Botch-Jones, Sabra; Foss, Jamie; Barajas, David; Kero, Frank; Young, Craig; Weisenseel, Jason

2016-10-01

New psychoactive substances (NPS) have been associated with fatalities and severe injuries in a number of cases in the United States and have led investigators to rethink traditional drug monitoring protocols. Of particular interest are the variable phenethylamine chemical structures known as 'NBOMes', which pose an emerging threat to public health with incidence steadily growing over the past decade. In this study, direct sample analysis (DSA)-time of flight mass spectrometry was employed to leverage rapid and sensitive ambient ionization mass spectrometry without chromatographic separation as verified with an authentic case sample. Samples for method development were prepared at Boston University School of Medicine's Biomedical Forensic Sciences program (Boston, MA) and analyzed at the State of Maine Health and Environmental Testing Laboratory's Forensic Chemistry Section (Augusta, ME). Preliminary method development work was performed at the University of Central Florida (Orlando, FL). DSA without any extraction step in addition to the evaluation of methanol, dichloromethane and hexane extractions were conducted. Methanol was found to not be a suitable extraction solvent for DSA analysis of these compounds. For the screening of NBOMe designer drug variables on blotter paper, DSA-TOFMS was successful at reducing analysis time to ∼15s per sample, for qualitative identification for the selected analytes of interest. The analysis of an authentic forensic case sample by DSA-TOFMS using the method development parameters demonstrates its utility in forensic laboratories. 25C-NBOMe was identified with an exact mass accuracy of 0.60ppm. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Understanding Angiography-Based Aneurysm Flow Fields through Comparison with Computational Fluid Dynamics.

PubMed

Cebral, J R; Mut, F; Chung, B J; Spelle, L; Moret, J; van Nijnatten, F; Ruijters, D

2017-06-01

Hemodynamics is thought to be an important factor for aneurysm progression and rupture. Our aim was to evaluate whether flow fields reconstructed from dynamic angiography data can be used to realistically represent the main flow structures in intracranial aneurysms. DSA-based flow reconstructions, obtained during interventional treatment, were compared qualitatively with flow fields obtained from patient-specific computational fluid dynamics models and quantitatively with projections of the computational fluid dynamics fields (by computing a directional similarity of the vector fields) in 15 cerebral aneurysms. The average similarity between the DSA and the projected computational fluid dynamics flow fields was 78% in the parent artery, while it was only 30% in the aneurysm region. Qualitatively, both the DSA and projected computational fluid dynamics flow fields captured the location of the inflow jet, the main vortex structure, the intrasaccular flow split, and the main rotation direction in approximately 60% of the cases. Several factors affect the reconstruction of 2D flow fields from dynamic angiography sequences. The most important factors are the 3-dimensionality of the intrasaccular flow patterns and inflow jets, the alignment of the main vortex structure with the line of sight, the overlapping of surrounding vessels, and possibly frame rate undersampling. Flow visualization with DSA from >1 projection is required for understanding of the 3D intrasaccular flow patterns. Although these DSA-based flow quantification techniques do not capture swirling or secondary flows in the parent artery, they still provide a good representation of the mean axial flow and the corresponding flow rate. © 2017 by American Journal of Neuroradiology.

Feasibility of intra-acquisition motion correction for 4D DSA reconstruction for applications in the thorax and abdomen

NASA Astrophysics Data System (ADS)

Wagner, Martin; Laeseke, Paul; Harari, Colin; Schafer, Sebastian; Speidel, Michael; Mistretta, Charles

2018-03-01

The recently proposed 4D DSA technique enables reconstruction of time resolved 3D volumes from two C-arm CT acquisitions. This provides information on the blood flow in neurovascular applications and can be used for the diagnosis and treatment of vascular diseases. For applications in the thorax and abdomen, respiratory motion can prevent successful 4D DSA reconstruction and cause severe artifacts. The purpose of this work is to propose a novel technique for motion compensated 4D DSA reconstruction to enable applications in the thorax and abdomen. The approach uses deformable 2D registration to align the projection images of a non-contrast and a contrast enhanced scan. A subset of projection images is then selected, which are acquired in a similar respiratory state and an iterative simultaneous multiplicative algebraic reconstruction is applied to determine a 3D constraint volume. A 2D-3D registration step then aligns the remaining projection images with the 3D constraint volume. Finally, a constrained back-projection is performed to create a 3D volume for each projection image. A pig study has been performed, where 4D DSA acquisitions were performed with and without respiratory motion to evaluate the feasibility of the approach. The dice similarity coefficient between the reference 3D constraint volume and the motion compensated reconstruction was 51.12 % compared to 35.99 % without motion compensation. This technique could improve the workflow for procedures in interventional radiology, e.g. liver embolizations, where changes in blood flow have to be monitored carefully.

Analysis of Radiation Effects in Digital Subtraction Angiography of Intracranial Artery Stenosis.

PubMed

Guo, Chaoqun; Shi, Xiaolei; Ding, Xianhui; Zhou, Zhiming

2018-04-21

Intracranial artery stenosis (IAS) is the most common cause for acute cerebral accidents. Digital subtraction angiography (DSA) is the gold standard to detect IAS and usually brings excess radiation exposure to examinees and examiners. The artery pathology might influence the interventional procedure, causing prolonged radiation effects. However, no studies on the association between IAS pathology and operational parameters are available. A retrospective analysis was conducted on 93 patients with first-ever stroke/transient ischemic attack, who received DSA examination within 3 months from onset in this single center. Comparison of baseline characteristics was determined by 2-tailed Student's t-test or the chi-square test between subjects with and without IAS. A binary logistic regression analysis was performed to determine the association between IAS pathology and the items with a P value <0.05 in Student's t-test or chi-square test. There were 93 candidates (42 with IAS and 51 without IAS) in this study. The 2 groups shared no significance of the baseline characteristics (P > 0.05). We found a significantly higher total time, higher kerma area product, greater total dose, and greater DSA dose in the IAS group than in those without IAS (P < 0.05). A binary logistic regression analysis indicated the significant association between total time and IAS pathology (P < 0.05) but no significance in kerma area product, radiation dose, and DSA dose (P > 0.05). IAS pathology would indicate a prolonged total time of DSA procedure in clinical practice. However, the radiation effects would not change with pathologic changes. Copyright © 2018 Elsevier Inc. All rights reserved.

Electrolyte additive enabled fast charging and stable cycling lithium metal batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jianming; Engelhard, Mark H.; Mei, Donghai

2017-03-01

Lithium (Li) metal battery is an attractive energy storage system owing to the ultrahigh specific capacity and the lowest redox potential of Li metal anode. However, safety concern associated with dendrite growth and limited cycle life especially at a high charge current density are two critical challenges hindering the practical applications of rechargeable Li metal batteries. Here, we report for the first time that an optimal amount (0.05 M) of LiPF6 as additive in the LiTFSI-LiBOB dual-salt/carbonate-based electrolyte can significantly enhance the charging capability and the long-term cycle life of Li metal batteries with a moderately high cathode loading ofmore » 1.75 mAh cm-2. Unprecedented stable-cycling (97.1% capacity retention after 500 cycles) along with very limited increase in electrode over-potential has been achieved at a high current density of 1.75 mA cm-2. This unparalleled fast charging and stable cycling performance is contributed from both the stabilized Al cathode current collector, and, more importantly, the robust and conductive SEI layer formed on Li metal anode in the presence of the LiPF6 additive.« less

Li 2OHCl crystalline electrolyte for stable metallic lithium anodes

DOE PAGES

Hood, Zachary D.; Wang, Hui; Samuthira Pandian, Amaresh; ...

2016-01-22

In a classic example of stability from instability, we show that Li 2OHCl solid electrolyte forms a stable solid electrolyte interface (SEI) with metallic lithium anode. The Li 2OHCl solid electrolyte can be readily achieved through simple mixing of air-stable LiOH and LiCl precursors with a mild processing temperature under 400 °C. Additionally, we show that continuous, dense Li 2OHCl membranes can be fabricated at temperatures less than 400 °C, standing in great contrast to current processing temperatures of over 1600 °C for most oxide-based solid electrolytes. The ionic conductivity and Arrhenius activation energy were explored for the LiOH-LiCl systemmore » of crystalline solid electrolytes where Li 2OHCl with increased crystal defects was found to have the highest ionic conductivity and reasonable Arrhenius activation energy. The Li 2OHCl solid electrolyte displays stability against metallic lithium, even in extreme conditions past the melting point of lithium metal. Furthermore, to understand this excellent stability, we show that SEI formation is critical in stabilizing the interface between metallic lithium and the Li 2OHCl solid electrolyte.« less

The BHEF National Higher Education and Workforce Initiative: A Model for Pathways to Baccalaureate Attainment and High-Skill Careers in Emerging Fields, Part 3

ERIC Educational Resources Information Center

Fitzgerald, Brian K.; Barkanic, Steve; Cárdenas-Navia, Isabel; Chen, Janet; Elzey, Karen; Hughes, Debbie; Troyan, Danielle

2016-01-01

BHEF has achieved particular success in operationalizing its National Higher Education and Workforce Initiative (HEWI) through regional initiatives in data science and analytics (DSA). Leveraging its membership of corporate CEOs, university presidents and government agency leaders, BHEF seeded new undergraduate pathways in DSA at Case Western…

IBM’s PIQUANT in TREC2003

DTIC Science & Technology

2003-01-01

La Bomba ,’’ ( the bomb ) for his explosive skiing style DSA P11 work: La Bomba LQA P12 most successful and popular Italian skier ever DSA P11...Alberto Tomba , Italy LQA P2 lawyer SQA job: champion LQA P6 work: Slalom for Peace LQA P12 born: Italy LQA P2 work: the Bomba LQA P12 some World Cup

Mesa redonda: Argentina en proyectos globales de investigaciones espaciales y astronómicas. Uso científico de la Antena de Espacio Profundo DSA 3

NASA Astrophysics Data System (ADS)

Colazo, M.

2016-08-01

Argentine has 10 percent of the operative time available for the DSA 3 Antenna of the European Space Agency, installed in Malargüe, Mendoza. Here we present the history of the project and the current activities for the scientific use of the antenna.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cavagna, Enrico; D'Andrea, Paolo; Schiavon, Francesco

Purpose: To evaluate failing hemodialysis arteriovenous fistulas with helical CT angiography (CTA), MR angiography (MRA), and digital subtraction angiography (DSA), and to compare the efficacy of the three techniques in detecting the number, location, grade, and extent of stenoses and in assessing the technical results of percutaneous transluminal angioplasty (PTA) and stenting.Methods: Thirteen patients with Brescia-Cimino arteriovenous fistula malfunction underwent MRA and CTA of the fistula and, within 1 week, DSA. A total of 11 PTAs were performed; in three cases an MR-compatible stent was placed. DSA served as the gold standard for comparison in all patients. The presence, site,more » and number of stenoses or occlusions and the technical results of percutaneous procedures were assessed with DSA, CTA, and MRA.Results: MRA underestimated a single stenosis in one patient; CTA and MRA did not overestimate any stenosis. Significant artifacts related to stent geometry and/or underlying metal were seen in MRA sequences in two cases.Conclusions: CT and MRI can provide information regarding the degree of vascular impairment, helping to stratify patients into those who can have PTA (single or multiple stenoses) versus those who require an operative procedure (occlusion). Conventional angiography can be reserved for candidates for percutaneous intervention.« less

Recent Advances in Allograft Vasculopathy

PubMed Central

Merola, Jonathan; Jane-Wit, Daniel D.; Pober, Jordan S.

2017-01-01

Purpose of review Despite considerable advances in controlling acute rejection, the longevity of cardiac and renal allografts remains significantly limited by chronic rejection in the form of allograft vasculopathy (AV). This review discusses recently reported mechanistic insights of AV pathogenesis as well recent clinical evaluations of new therapeutic approaches. Recent findings Although adaptive immunity is the major driver of AV, natural killer cells mediate vasculopathic changes in a transplanted mouse heart following treatment with donor-specific antibody (DSA). However, NK cells may also dampen chronic inflammatory responses by killing donor-derived tissue-resident CD4 T cells that provide help to host B cells, the source of DSA. DSA may directly contribute to vascular inflammation by inducing intracellular signaling cascades that upregulate leukocyte adhesion molecules, facilitating recruitment of neutrophils and monocytes. DSA-mediated complement activation additionally enhances endothelial alloimmunogenicity through activation of non-canonical NF-κB signaling. New clinical studies evaluating mTOR and proteasome inhibitors to target these pathways have been reported. Summary AV is a pathology resultant from several innate and adaptive alloimmune responses. Mechanistic insights from preclinical studies have identified agents that are currently being investigated in clinical trials. PMID:27898462

Customization and design of directed self-assembly using hybrid prepatterns

NASA Astrophysics Data System (ADS)

Cheng, Joy; Doerk, Gregory S.; Rettner, Charles T.; Singh, Gurpreet; Tjio, Melia; Truong, Hoa; Arellano, Noel; Balakrishnan, Srinivasan; Brink, Markus; Tsai, Hsinyu; Liu, Chi-Chun; Guillorn, Michael; Sanders, Daniel P.

2015-03-01

Diminishing error tolerance renders the customization of patterns created through directed self-assembly (DSA) extremely challenging at tighter pitch. A self-aligned customization scheme can be achieved using a hybrid prepattern comprising both organic and inorganic regions that serves as a guiding prepattern to direct the self-assembly of the block copolymers as well as a cut mask pattern for the DSA arrays aligned to it. In this paper, chemoepitaxy-based self-aligned customization is demonstrated using two types of organic-inorganic prepatterns. CHEETAH prepattern for "CHemoepitaxy Etch Trim using a self-Aligned Hardmask" of preferential hydrogen silsesquioxane (HSQ, inorganic resist), non-preferential organic underlayer is fabricated using electron beam lithography. Customized trench or hole arrays can be achieved through co-transfer of DSA-formed arrays and CHEETAH prepattern. Herein, we also introduce a tone-reversed version called reverse-CHEETAH (or rCHEETAH) in which customized line segments can be achieved through co-transfer of DSA-formed arrays formed on a prepattern wherein the inorganic HSQ regions are nonpreferential and the organic regions are PMMA preferential. Examples of two-dimensional self-aligned customization including 25nm pitch fin structures and an 8-bar "IBM" illustrate the versatility of this customization scheme using rCHEETAH.

3D printing of intracranial aneurysm based on intracranial digital subtraction angiography and its clinical application.

PubMed

Wang, Jian-Li; Yuan, Zi-Gang; Qian, Guo-Liang; Bao, Wu-Qiao; Jin, Guo-Liang

2018-06-01

The study aimed to develop simulation models including intracranial aneurysmal and parent vessel geometries, as well as vascular branches, through 3D printing technology. The simulation models focused on the benefits of aneurysmal treatments and clinical education. This prospective study included 13 consecutive patients who suffered from intracranial aneurysms confirmed by digital subtraction angiography (DSA) in the Neurosurgery Department of Shaoxing People's Hospital. The original 3D-DSA image data were extracted through the picture archiving and communication system and imported into Mimics. After reconstructing and transforming to Binary STL format, the simulation models of the hollow vascular tree were printed using 3D devices. The intracranial aneurysm 3D printing simulation model was developed based on DSA to assist neurosurgeons in aneurysmal treatments and residency training. Seven neurosurgical residents and 15 standardization training residents received their simulation model training and gave high assessments for the educational course with the follow-up qualitative questionnaire. 3D printed simulation models based on DSA can perfectly reveal target aneurysms and help neurosurgeons select therapeutic strategies precisely. As an educational tool, the 3D aneurysm vascular simulation model is useful for training residents.

64-slice MDCT angiography of upper extremity in assessment of native hemodialysis access.

PubMed

Wasinrat, Jitladda; Siriapisith, Thanongchai; Thamtorawat, Somrach; Tongdee, Trongtum

2011-01-01

To compare multidetector row computed tomographic (MDCT) angiography with conventional digital subtraction angiography (DSA) in the evaluation of vascular access stenoses in hemodialysis patients. Twenty-one consecutive patients were imaged with MDCT angiography and subsequent DSA. The superficial vein of leg was used as the route for intravenous administration. The vascular stenosis was assessed in not significant (<50% stenosis), moderate stenosis (50%-74% stenosis), severe stenosis (75%-99%), and total occlusion (100%). The accuracy, sensitivity, specificity, positive, and negative predictive values were calculated for significant vascular stenosis using DSA as the standard reference. The sensitivity and specificity of MDCT angiography for the detection of significant hemodialysis vascular access were 100% (95% CI, 89.3%-100%) and 94.8% (95% CI, 89.1%-97.6%), respectively. The positive and negative predictive values were 84.2% (95% CI, 68.1%-93.4%) and 100% (95% CI, 95.8%-100%), respectively. The accuracy of MDCT angiography for detection of significant stenoses was 95.9% (95% CI, 91.4%-97.0%). MDCT angiography provides excellent correlation in vascular stenosis as compared with DSA in hemodialysis access. Complete assessment of entire vascular segments could be performing with MDCT angiography in planning before endovascular intervention or surgical correction.

Three-dimensional stable lithium metal anode with nanoscale lithium islands embedded in ionically conductive solid matrix

PubMed Central

Lin, Dingchang; Zhao, Jie; Sun, Jie; Yao, Hongbin; Liu, Yayuan; Yan, Kai; Cui, Yi

2017-01-01

Rechargeable batteries based on lithium (Li) metal chemistry are attractive for next-generation electrochemical energy storage. Nevertheless, excessive dendrite growth, infinite relative dimension change, severe side reactions, and limited power output severely impede their practical applications. Although exciting progress has been made to solve parts of the above issues, a versatile solution is still absent. Here, a Li-ion conductive framework was developed as a stable “host” and efficient surface protection to address the multifaceted problems, which is a significant step forward compared with previous host concepts. This was fulfilled by reacting overstoichiometry of Li with SiO. The as-formed LixSi–Li2O matrix would not only enable constant electrode-level volume, but also protect the embedded Li from direct exposure to electrolyte. Because uniform Li nucleation and deposition can be fulfilled owing to the high-density active Li domains, the as-obtained nanocomposite electrode exhibits low polarization, stable cycling, and high-power output (up to 10 mA/cm2) even in carbonate electrolytes. The Li–S prototype cells further exhibited highly improved capacity retention under high-power operation (∼600 mAh/g at 6.69 mA/cm2). The all-around improvement on electrochemical performance sheds light on the effectiveness of the design principle for developing safe and stable Li metal anodes. PMID:28416664

The design of a Li-ion full cell battery using a nano silicon and nano multi-layer graphene composite anode

NASA Astrophysics Data System (ADS)

Eom, KwangSup; Joshi, Tapesh; Bordes, Arnaud; Do, Inhwan; Fuller, Thomas F.

2014-03-01

In this study, a Si-graphene composite, which is composed of nano Si particles and nano-sized multi-layer graphene particles, and micro-sized multi-layer graphene plate conductor, was used as the anode for Li-ion battery. The Si-graphene electrode showed the high capacity and stable cyclability at charge/discharge rate of C/2 in half cell tests. Nickel cobalt aluminum material (NCA) was used as a cathode in the full cell to evaluate the practicality of the new Si-graphene material. Although the Si-graphene anode has more capacity than the NCA cathode in this designed full cell, the Si-graphene anode had a greater effect on the full-cell performance due to its large initial irreversible capacity loss and continuous SEI formation during cycling. When fluoro-ethylene carbonate was added to the electrolyte, the cyclability of the full cell was much improved due to less SEI formation, which was confirmed by the decreases in the 1st irreversible capacity loss, overpotential for the 1st lithiation, and the resistance of the SEI.

Effects of Zn-In-Sn elements on the electric properties of magnesium alloy anode materials.

PubMed

Yu, Zhan; Ju, Dongying; Zhao, Hongyang; Hu, Xiaodong

2011-06-01

A new magnesium alloy anode is based on an environmentally friendly electrode that contains none of mercury, lead and chromate, but it can enhance the electric properties of alloy significantly. Magnesium alloy adding eco-friendly elements Zn-In-Sn which was developed by orthogonal design were obtained by two casting methods. The effect of additive elements on performance of electrode material was studied. The effects of elements addition and casting method on electric properties and corrosive properties of Mg-Zn-In-Sn alloys were investigated by using electrochemical measurements, corrosive tests and observation of surface structure. The results show that Mg-Zn-In-Sn alloy anode has higher electromotive force and more stable work potential than that commercial magnesium alloy AZ91. It is suitable for anode material of magnesium battery for its small hydrogen evolution, less self-corrosion rate and easy to shed corrosive offspring off. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Carbon/tin oxide composite electrodes for improved lithium-ion batteries

DOE PAGES

Li, Yunchao; Levine, Alan M.; Zhang, Jinshui; ...

2018-05-17

Tin and tin oxide-based electrodes are promising high-capacity anodes for lithium-ion batteries. However, poor capacity retention is the major issue with these materials due to the large volumetric expansion that occurs when lithium is alloyed with tin during lithiation and delithiation process. Here, a method to prepare a low-cost, scalable carbon and tin(II) oxide composite anode is reported. The composite material was prepared by ball milling of carbon recovered from used tire powders with 25 wt% tin(II) oxide to form lithium-ion battery anode. With the impact of energy from the ball milling, tin oxide powders were uniformly distributed inside themore » pores of waste-tire-derived carbon. During lithiation and delithiation, the carbon matrix can effectively absorb the volume expansion caused by tin, thereby minimizing pulverization and capacity fade of the electrodes. In conclusion, the as-synthesized anode yielded a capacity of 690 mAh g –1 after 300 cycles at a current density of 40 mA g –1 with a stable battery performance.« less

Cryogenic plasma-processed silicon microspikes as a high-performance anode material for lithium ion-batteries

NASA Astrophysics Data System (ADS)

Sakai, Joe; Luais, Erwann; Wolfman, Jérôme; Tillocher, Thomas; Dussart, Rémi; Tran-Van, Francois; Ghamouss, Fouad

2017-10-01

Micro- or nano-structuring is essential in order to use Si as an anode material for lithium ion batteries. In the present study, we attempted to use Si wafers with a spiky microstructure (SMS), the so-called black-Si, prepared by a cryogenic reactive ion etching process with an SF6/O2 gas mixture, for Li half-cells. The SMS with various sizes of spikes from 2.0 μm (height) × 0.2 μm (width) to 21 μm × 1.0 μm was etched by varying the SF6/O2 gas flow ratio. An anode of SMS of 11 μm-height in average showed stable charge/discharge capacity and Coulombic efficiency higher than 99% for more than 300 cycles, causing no destruction to any part of the Si wafer. The spiky structure turned columnar after cycles, suggesting graded lithiation levels along the length. The present results suggest a strategy to utilize a wafer-based Si material for an anode of a lithium ion battery durable against repetitive lithiation/delithiation cycles.

A long life 4 V class lithium-ion polymer battery with liquid-free polymer electrolyte

NASA Astrophysics Data System (ADS)

Kobayashi, Yo; Shono, Kumi; Kobayashi, Takeshi; Ohno, Yasutaka; Tabuchi, Masato; Oka, Yoshihiro; Nakamura, Tatsuya; Miyashiro, Hajime

2017-02-01

Ether-based solid polymer electrolyte (SPE) is one of the most well-known lithium ion conductors. Unlike the other inorganic electrolytes, SPE exhibits advantages of flexibility and large-area production, enabling low cost production of large size batteries. However, because the ether group is oxidized at 4 V versus Li/Li+ cathode, and due to its high irreversibility with the carbon anode, ether-based SPE was believed to be inapplicable to 4 V class lithium-ion batteries with carbon anode. Here we report a remarkably stable SPE in combination with a 4 V class cathode and carbon anode achieved by the proper design at the interface. The introduced boron-based lithium salt prohibits further oxidation of SPE at the cathode interface. The surface modification of graphite by the annealing of polyvinyl chloride mostly prohibits the continuous consumption of lithium at the graphite anode. Using above interface design, we achieved 60% capacity retention after 5400 cycles. The proposed battery provides a possible approach for realizing flammable electrolyte-free lithium-ion batteries, which achieve innovative safety improvements of large format battery systems for stationary use.

Carbon/tin oxide composite electrodes for improved lithium-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yunchao; Levine, Alan M.; Zhang, Jinshui

Tin and tin oxide-based electrodes are promising high-capacity anodes for lithium-ion batteries. However, poor capacity retention is the major issue with these materials due to the large volumetric expansion that occurs when lithium is alloyed with tin during lithiation and delithiation process. Here, a method to prepare a low-cost, scalable carbon and tin(II) oxide composite anode is reported. The composite material was prepared by ball milling of carbon recovered from used tire powders with 25 wt% tin(II) oxide to form lithium-ion battery anode. With the impact of energy from the ball milling, tin oxide powders were uniformly distributed inside themore » pores of waste-tire-derived carbon. During lithiation and delithiation, the carbon matrix can effectively absorb the volume expansion caused by tin, thereby minimizing pulverization and capacity fade of the electrodes. In conclusion, the as-synthesized anode yielded a capacity of 690 mAh g –1 after 300 cycles at a current density of 40 mA g –1 with a stable battery performance.« less

Synthesis of Li2Ti3O7 Anode Materials by Ultrasonic Spray Pyrolysis and Their Electrochemical Properties

PubMed Central

Ogihara, Takashi; Kodera, Takayuki

2013-01-01

Ramsdellite-type lithium titanate (Li2Ti3O7) powders were synthesized by performing ultrasonic spray pyrolysis, and their chemical and physical properties were characterized by performing Scanning Electron Microscope (SEM), powder X-ray Diffraction (XRD), and Inductively Coupled Plasma (ICP) analyses. The as-prepared Li2Ti3O7 precursor powders had spherical morphologies with hollow microstructures, but an irregularly shaped morphology was obtained after calcination above 900 °C. The ramsdellite Li2Ti3O7 crystal phase was obtained after the calcination at 1100 °C under an argon/hydrogen atmosphere. The first rechargeable capacity of the Li2Ti3O7 anode material was 168 mAh/g at 0.1 C and 82 mAh/g at 20 C, and the discharge capacity retention ratio was 99% at 1 C after the 500th cycle. The cycle performance of the Li2Ti3O7 anode was also highly stable at 50 °C, demonstrating the superiority of Li2Ti3O7 anode materials reported previously. PMID:28809274

Electrochemical impedance spectroscopy analysis of a thin polymer film-based micro-direct methanol fuel cell

NASA Astrophysics Data System (ADS)

Schulz, Tobias; Weinmüller, Christian; Nabavi, Majid; Poulikakos, Dimos

A single cell micro-direct methanol fuel cell (micro-DMFC) was investigated using electrochemical impedance spectroscopy. The electrodes consisted of thin, flexible polymer (SU8) film microchannel structures fabricated in-house using microfabrication techniques. AC impedance spectroscopy was used to separate contributions to the overall cell polarization from the anode, cathode and membrane. A clear distinction between the different electrochemical phenomena occurring in the micro-DMFC, especially the distinction between double layer charging and Faradaic reactions was shown. The effect of fuel flow rate, temperature, and anode flow channel structure on the impedance of the electrode reactions and membrane/electrode double layer charging were investigated. Analysis of impedance data revealed that the performance of the test cell was largely limited by the presence of intermediate carbon monoxide in the anode reaction. Higher temperatures increase cell performance by enabling intermediate CO to be oxidized at much higher rates. The results also revealed that serpentine anode flow microchannels show a lower tendency to intermediate CO coverage and a more stable cell behavior than parallel microchannels.

An artificial interphase enables reversible magnesium chemistry in carbonate electrolytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Son, Seoung-Bum; Gao, Tao; Harvey, Steve P.

Magnesium-based batteries possess potential advantages over their lithium counterparts. However, reversible Mg chemistry requires a thermodynamically stable electrolyte at low potential, which is usually achieved with corrosive components and at the expense of stability against oxidation. In lithium-ion batteries the conflict between the cathodic and anodic stabilities of the electrolytes is resolved by forming an anode interphase that shields the electrolyte from being reduced. This strategy cannot be applied to Mg batteries because divalent Mg2+ cannot penetrate such interphases. Here, we engineer an artificial Mg2+-conductive interphase on the Mg anode surface, which successfully decouples the anodic and cathodic requirements formore » electrolytes and demonstrate highly reversible Mg chemistry in oxidation-resistant electrolytes. The artificial interphase enables the reversible cycling of a Mg/V2O5 full-cell in the water-containing, carbonate-based electrolyte. This approach provides a new avenue not only for Mg but also for other multivalent-cation batteries facing the same problems, taking a step towards their use in energy-storage applications.« less

Structural changes in a commercial lithium-ion battery during electrochemical cycling: An in situ neutron diffraction study

NASA Astrophysics Data System (ADS)

Sharma, Neeraj; Peterson, Vanessa K.; Elcombe, Margaret M.; Avdeev, Maxim; Studer, Andrew J.; Blagojevic, Ned; Yusoff, Rozila; Kamarulzaman, Norlida

The structural response to electrochemical cycling of the components within a commercial Li-ion battery (LiCoO 2 cathode, graphite anode) is shown through in situ neutron diffraction. Lithuim insertion and extraction is observed in both the cathode and anode. In particular, reversible Li incorporation into both layered and spinel-type LiCoO 2 phases that comprise the cathode is shown and each of these components features several phase transitions attributed to Li content and correlated with the state-of-charge of the battery. At the anode, a constant cell voltage correlates with a stable lithiated graphite phase. Transformation to de-lithiated graphite at the discharged state is characterised by a sharp decrease in both structural cell parameters and cell voltage. In the charged state, a two-phase region exists and is composed of the lithiated graphite phase and about 64% LiC 6. It is postulated that trapping Li in the solid|electrolyte interface layer results in minimal structural changes to the lithiated graphite anode across the constant cell voltage regions of the electrochemical cycle.

Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries

PubMed Central

Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

2016-01-01

The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA. PMID:26786315

Dendrite-free Li metal anode enabled by a 3D free-standing lithiophilic nitrogen-enriched carbon sponge

NASA Astrophysics Data System (ADS)

Hou, Guangmei; Ren, Xiaohua; Ma, Xiaoxin; Zhang, Le; Zhai, Wei; Ai, Qing; Xu, Xiaoyan; Zhang, Lin; Si, Pengchao; Feng, Jinkui; Ding, Fei; Ci, Lijie

2018-05-01

Lithium metal is considered as the ultimate anode material for high-energy Li battery systems. However, the commercial application of lithium anode is impeded by issues with safety and low coulombic efficiency induced by Li dendrite growth. Herein, a free-standing three-dimensional nitrogen-enriched graphitic carbon sponge with a high nitrogen content is proposed as a multifunctional current collect for Lithium accommodation. The abundant lithiophilic N-containing functional groups are served as preferred nucleation sites to guide a uniform Li deposition. In addition, the nitrogen-enriched graphitic carbon sponge with a high specific surface area can effectively reduce the local current density. As a result of the synergistic effect, the nitrogen-enriched graphitic carbon sponge electrode realizes a long-term stable cycling without dendrites formation. Notably, the as-obtained composite electrode can deliver an ultra-high specific capacity of ∼3175 mA h g-1. The nitrogen-enriched graphitic carbon sponge might provide innovative insights to design a superior matrix for dendrite-free Li anode.

Porous Carbon Paper as Interlayer to Stabilize the Lithium Anode for Lithium-Sulfur Battery.

PubMed

Kong, Ling-Long; Zhang, Ze; Zhang, Ye-Zheng; Liu, Sheng; Li, Guo-Ran; Gao, Xue-Ping

2016-11-23

The lithium-sulfur (Li-S) battery is expected to be the high-energy battery system for the next generation. Nevertheless, the degradation of lithium anode in Li-S battery is the crucial obstacle for practical application. In this work, a porous carbon paper obtained from corn stalks via simple treating procedures is used as interlayer to stabilize the surface morphology of Li anode in the environment of Li-S battery. A smooth surface morphology of Li is obtained during cycling by introducing the porous carbon paper into Li-S battery. Meanwhile, the electrochemical performance of sulfur cathode is partially enhanced by alleviating the loss of soluble intermediates (polysulfides) into the electrolyte, as well as the side reaction of polysulfides with metallic lithium. The Li-S battery assembled with the interlayer exhibits a large capacity and excellent capacity retention. Therefore, the porous carbon paper as interlayer plays a bifunctional role in stabilizing the Li anode and enhancing the electrochemical performance of the sulfur cathode for constructing a stable Li-S battery.

High-Q Wafer Level Package Based on Modified Tri-Layer Anodic Bonding and High Performance Getter and Its Evaluation for Micro Resonant Pressure Sensor.

PubMed

Wang, Liying; Du, Xiaohui; Wang, Lingyun; Xu, Zhanhao; Zhang, Chenying; Gu, Dandan

2017-03-16

In order to achieve and maintain a high quality factor (high-Q) for the micro resonant pressure sensor, this paper presents a new wafer level package by adopting cross-layer anodic bonding technique of the glass/silicon/silica (GSS) stackable structure and integrated Ti getter. A double-layer structure similar to a silicon-on-insulator (SOI) wafer is formed after the resonant layer and the pressure-sensitive layer are bonded by silicon direct bonding (SDB). In order to form good bonding quality between the pressure-sensitive layer and the glass cap layer, the cross-layer anodic bonding technique is proposed for vacuum package by sputtering Aluminum (Al) on the combination wafer of the pressure-sensitive layer and the resonant layer to achieve electrical interconnection. The model and the bonding effect of this technique are discussed. In addition, in order to enhance the performance of titanium (Ti) getter, the prepared and activation parameters of Ti getter under different sputtering conditions are optimized and discussed. Based on the optimized results, the Ti getter (thickness of 300 nm to 500 nm) is also deposited on the inside of the glass groove by magnetron sputtering to maintain stable quality factor (Q). The Q test of the built testing system shows that the number of resonators with a Q value of more than 10,000 accounts for more than 73% of the total. With an interval of 1.5 years, the Q value of the samples remains almost constant. It proves the proposed cross-layer anodic bonding and getter technique can realize high-Q resonant structure for long-term stable operation.

Fluoroethylene Carbonate as a Directing Agent in Amorphous Silicon Anodes: Electrolyte Interface Structure Probed by Sum Frequency Vibrational Spectroscopy and Ab Initio Molecular Dynamics.

PubMed

Horowitz, Yonatan; Han, Hui-Ling; Soto, Fernando A; Ralston, Walter T; Balbuena, Perla B; Somorjai, Gabor A

2018-02-14

Fluorinated compounds are added to carbonate-based electrolyte solutions in an effort to create a stable solid electrolyte interphase (SEI). The SEI mitigates detrimental electrolyte redox reactions taking place on the anode's surface upon applying a potential in order to charge (discharge) the lithium (Li) ion battery. The need for a stable SEI is dire when the anode material is silicon as silicon cracks due to its expansion and contraction upon lithiation and delithiation (charge-discharge) cycles, consequently limiting the cyclability of a silicon-based battery. Here we show the molecular structures for ethylene carbonate (EC): fluoroethylene carbonate (FEC) solutions on silicon surfaces by sum frequency generation (SFG) vibrational spectroscopy, which yields vibrational spectra of molecules at interfaces and by ab initio molecular dynamics (AIMD) simulations at open circuit potential. Our AIMD simulations and SFG spectra indicate that both EC and FEC adsorb to the amorphous silicon (a-Si) through their carbonyl group (C═O) oxygen atom with no further desorption. We show that FEC additives induce the reorientation of EC molecules to create an ordered, up-right orientation of the electrolytes on the Si surface. We suggest that this might be helpful for Li diffusion under applied potential. Furthermore, FEC becomes the dominant species at the a-Si surface as the FEC concentration increases above 20 wt %. Our finding at open circuit potential can now initiate additive design to not only act as a sacrificial compound but also to produce a better suited SEI for the use of silicon anodes in the Li-ion vehicular industry.

Improved anode materials for lithium-ion batteries comprise non-covalently bonded graphene and silicon nanoparticles

NASA Astrophysics Data System (ADS)

Ye, Yun-Sheng; Xie, Xiao-Lin; Rick, John; Chang, Feng-Chih; Hwang, Bing-Joe

2014-02-01

Si, when compared to conventional graphite, offers an order-of-magnitude improvement as a high capacity anode material for Li-ion batteries. Despite significant advances in nanostructured Si-based anodes, the formation of stable Si anodes remains a challenge, due to the significant volume changes that occur during lithiation and delithiation. Si/graphene composites, with graphene sheets and Si nanoparticles bound in a dispersion obtained by a self-assembly technique using non-covalent electrostatic attraction (following thermal processing to remove residual organic material) are used to prepare Si-based anodes for use in Li-ion batteries. A mesoporous structure, obtained by further thermal processing is able to accommodate large Si nanoparticle volume changes during cycling, thereby facilitating Li-ion diffusion within the electrode. Morphological analysis showed that Si nanoparticles are homogeneously distributed on the graphene sheets, which is thought to account for the excellent electrochemical performance of the resulting Si/graphene composite. A composite containing Si 67.3 wt% exhibits a greatly improved capacity and cycling stability in comparison with bare Si in combination with the thermal reduction of a simple mixture of graphene oxide and Si nanoparticles without electrostatic attraction (Si content = 64.6 wt%; capacity of 512 mAh g-1 in 40th cycle).

Removal of ammonium ion from produced waters in petroleum offshore exploitation by a batch single-stage electrolytic process.

PubMed

de Lima, Rosilda Maria Gomes; da Silva Wildhagen, Glória Regina; da Cunha, José Waldemar Silva Dias; Afonso, Julio Carlos

2009-01-30

This work describes a batch single-stage electrochemical process to remove quantitatively the ammonium ion from produced waters from petroleum exploration of the Campos' Basin, seeking to fulfil the directories of the National Brazilian Environmental Council. The anode was made out of titanium covered by a layer of RuO(2)+TiO(2) oxides (Dimensionally Stable Anode), whereas the cathode was made out of pure titanium. Anodic and cathodic compartments were separated by a membrane. The applied current varied from 0.3 to 1.5A. As the current increased NH(4)(+) removal was faster and pH was rapidly decreased to 3. The pH of the anodic compartment increased to approximately 10. When the current was 0.92 A chlorine evolution was observed after 40 min or only 15 min when that current was 1.50 A. In this voltage a deposit containing alkali-earth metal hydroxides/sulphates was formed on the membrane surface of the cathode side, thus suggesting a diffusion process from the anodic to the cathodic compartment. The maximum current applied to the cell must not exceed approximately 0.70 A in order to avoid chlorine evolution. Ammonia removal was over 99.9 wt% at 0.68 A in about 75 min.

Electricity generation from acetate and glucose by sedimentary bacterium attached to electrode in microbial-anode fuel cells

NASA Astrophysics Data System (ADS)

Zhang, Enren; Xu, Wei; Diao, Guowang; Shuang, Chendong

Microbial-anode fuel cells (MAFCs) with high electron recovery (>50%) from acetate and glucose have been constructed in this study. By inoculating fresh sedimentary microorganisms into anaerobic anode compartments, a stable current (∼0.42 mA for acetate-fed MAFCs; ∼0.35 mA for glucose-fed MAFCs) is generated from the oxidation of the added organic matter until its concentration decreases to a low level. SEM micrographs indicate that thick biofilms of microbial communities (coccoid cells with a diameter of ∼0.5 μm in acetate-fed MAFCs; rod-shaped cells with a length of 2.0-4.0 μm and a width of 0.5-0.7 μm in glucose-fed MAFCs) completely cover the anode electrodes. These anodophillic biofilms are thought to be responsible for the current generation, and make these microbial-anode fuel cells exhibit good performance even when the growth medium is replaced by a salt buffer without any growth factor. In comparison with those microbial fuel cells that require the addition of artificial electron transfer-mediating compounds, the findings in this study imply a potential way to develop excellent mediator-less MAFCs for electricity generation from organic matter by using substrate-induced anodophillic microbial species.

Bending-Tolerant Anodes for Lithium-Metal Batteries.

PubMed

Wang, Aoxuan; Tang, Shan; Kong, Debin; Liu, Shan; Chiou, Kevin; Zhi, Linjie; Huang, Jiaxing; Xia, Yong-Yao; Luo, Jiayan

2018-01-01

Bendable energy-storage systems with high energy density are demanded for conformal electronics. Lithium-metal batteries including lithium-sulfur and lithium-oxygen cells have much higher theoretical energy density than lithium-ion batteries. Reckoned as the ideal anode, however, Li has many challenges when directly used, especially its tendency to form dendrite. Under bending conditions, the Li-dendrite growth can be further aggravated due to bending-induced local plastic deformation and Li-filaments pulverization. Here, the Li-metal anodes are made bending tolerant by integrating Li into bendable scaffolds such as reduced graphene oxide (r-GO) films. In the composites, the bending stress is largely dissipated by the scaffolds. The scaffolds have increased available surface for homogeneous Li plating and minimize volume fluctuation of Li electrodes during cycling. Significantly improved cycling performance under bending conditions is achieved. With the bending-tolerant r-GO/Li-metal anode, bendable lithium-sulfur and lithium-oxygen batteries with long cycling stability are realized. A bendable integrated solar cell-battery system charged by light with stable output and a series connected bendable battery pack with higher voltage is also demonstrated. It is anticipated that this bending-tolerant anode can be combined with further electrolytes and cathodes to develop new bendable energy systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method of fabricating a monolithic core for a solid oxide fuela cell

DOEpatents

Zwick, S.A.; Ackerman, J.P.

1983-10-12

A method is disclosed for forming a core for use in a solid oxide fuel cell that electrochemically combines fuel and oxidant for generating galvanic output. The core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support consisting instead only of the active anode, cathode, electrolyte and interconnect materials. Each electrolyte wall consists of cathode and anode materials sandwiching electrolyte material therebetween, and each interconnect wall consists of the cathode and anode materials sandwiching interconnect material therebetween. The electrolyte and interconnect walls define a plurality of substantially parallel core passageways alternately having respectively the inside faces thereof with only the anode material or with only the cathode material exposed. In the wall structure, the electrolyte and interconnect materials are only 0.002 to 0.01 cm thick; and the cathode and anode materials are only 0.002 to 0.05 cm thick. The method consists of building up the electrolyte and interconnect walls by depositing each material on individually and endwise of the wall itself, where each material deposit is sequentially applied for one cycle; and where the depositing cycle is repeated many times until the material buildup is sufficient to formulate the core. The core is heat cured to become dimensionally and structurally stable.

Method of fabricating a monolithic core for a solid oxide fuel cell

DOEpatents

Zwick, Stanley A.; Ackerman, John P.

1985-01-01

A method is disclosed for forming a core for use in a solid oxide fuel cell that electrochemically combines fuel and oxidant for generating galvanic output. The core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support consisting instead only of the active anode, cathode, electrolyte and interconnect materials. Each electrolyte wall consists of cathode and anode materials sandwiching electrolyte material therebetween, and each interconnect wall consists of the cathode and anode materials sandwiching interconnect material therebetween. The electrolyte and interconnect walls define a plurality of substantially parallel core passageways alternately having respectively the inside faces thereof with only the anode material or with only the cathode material exposed. In the wall structure, the electrolyte and interconnect materials are only 0.002-0.01 cm thick; and the cathode and anode materials are only 0.002-0.05 cm thick. The method consists of building up the electrolyte and interconnect walls by depositing each material on individually and endwise of the wall itself, where each material deposit is sequentially applied for one cycle; and where the depositing cycle is repeated many times until the material buildup is sufficient to formulate the core. The core is heat cured to become dimensionally and structurally stable.

34 CFR 367.11 - What assurances must a DSA include in its application?

Code of Federal Regulations, 2011 CFR

2011-07-01

... State plan under section 704 of the Act any new methods and approaches relating to IL services for older... expended only for the purposes described in § 367.1; (b) With respect to the costs of the program to be... be effective; (d) At the end of each fiscal year, the DSA will prepare and submit to the Secretary a...

34 CFR 367.11 - What assurances must a DSA include in its application?

Code of Federal Regulations, 2010 CFR

2010-07-01

... State plan under section 704 of the Act any new methods and approaches relating to IL services for older... expended only for the purposes described in § 367.1; (b) With respect to the costs of the program to be... be effective; (d) At the end of each fiscal year, the DSA will prepare and submit to the Secretary a...

A Case Study: Analyzing City Vitality with Four Pillars of Activity-Live, Work, Shop, and Play.

PubMed

Griffin, Matt; Nordstrom, Blake W; Scholes, Jon; Joncas, Kate; Gordon, Patrick; Krivenko, Elliott; Haynes, Winston; Higdon, Roger; Stewart, Elizabeth; Kolker, Natali; Montague, Elizabeth; Kolker, Eugene

2016-03-01

This case study evaluates and tracks vitality of a city (Seattle), based on a data-driven approach, using strategic, robust, and sustainable metrics. This case study was collaboratively conducted by the Downtown Seattle Association (DSA) and CDO Analytics teams. The DSA is a nonprofit organization focused on making the city of Seattle and its Downtown a healthy and vibrant place to Live, Work, Shop, and Play. DSA primarily operates through public policy advocacy, community and business development, and marketing. In 2010, the organization turned to CDO Analytics ( cdoanalytics.org ) to develop a process that can guide and strategically focus DSA efforts and resources for maximal benefit to the city of Seattle and its Downtown. CDO Analytics was asked to develop clear, easily understood, and robust metrics for a baseline evaluation of the health of the city, as well as for ongoing monitoring and comparisons of the vitality, sustainability, and growth. The DSA and CDO Analytics teams strategized on how to effectively assess and track the vitality of Seattle and its Downtown. The two teams filtered a variety of data sources, and evaluated the veracity of multiple diverse metrics. This iterative process resulted in the development of a small number of strategic, simple, reliable, and sustainable metrics across four pillars of activity: Live, Work, Shop, and Play. Data during the 5 years before 2010 were used for the development of the metrics and model and its training, and data during the 5 years from 2010 and on were used for testing and validation. This work enabled DSA to routinely track these strategic metrics, use them to monitor the vitality of Downtown Seattle, prioritize improvements, and identify new value-added programs. As a result, the four-pillar approach became an integral part of the data-driven decision-making and execution of the Seattle community's improvement activities. The approach described in this case study is actionable, robust, inexpensive, and easy to adopt and sustain. It can be applied to cities, districts, counties, regions, states, or countries, enabling cross-comparisons and improvements of vitality, sustainability, and growth.

Carotid DSA based CFD simulation in assessing the patient with asymptomatic carotid stenosis: a preliminary study.

PubMed

Zhang, Dong; Xu, Pengcheng; Qiao, Hongyu; Liu, Xin; Luo, Liangping; Huang, Wenhua; Zhang, Heye; Shi, Changzheng

2018-03-12

Cerebrovascular events are frequently associated with hemodynamic disturbance caused by internal carotid artery (ICA) stenosis. It is challenging to determine the ischemia-related carotid stenosis during the intervention only using digital subtracted angiography (DSA). Inspired by the performance of well-established FFRct technique in hemodynamic assessment of significant coronary stenosis, we introduced a pressure-based carotid arterial functional assessment (CAFA) index generated from computational fluid dynamic (CFD) simulation in DSA data, and investigated its feasibility in the assessment of hemodynamic disturbance preliminarily using pressure-wired measurement and arterial spin labeling (ASL) MRI as references. The cerebral multi-delay multi-parametric ASL-MRI and carotid DSA including trans-stenotic pressure-wired measurement were implemented on a 65-year-old man with asymptomatic unilateral (left) ICA stenosis. A CFD simulation using simplified boundary condition was performed in DSA data to calculate the CAFA index. The cerebral blood flow (CBF) and arterial transit time (ATT) of ICA territories were acquired. CFD simulation showed good correlation (r = 0.839, P = 0.001) with slight systematic overestimation (mean difference - 0.007, standard deviation 0.017) compared with pressure-wired measurement. No significant difference was observed between them (P = 0.09). Though the narrowing degree of in the involved ICA was about 70%, the simulated and measured CAFA (0.942/0.937) revealed a functionally nonsignificant stenosis which was also verified by a compensatory final CBF (fronto-temporal/fronto-parietal region: 51.58/45.62 ml/100 g/min) and slightly prolonged ATT (1.23/1.4 s) in the involved territories, together with a normal left-right percentage difference (2.1-8.85%). The DSA based CFD simulation showed good consistence with invasive approach and could be used as a cost-saving and efficient way to study the relationship between hemodynamic disorder caused by ICA stenosis and subsequent perfusion variations in brain. Further research should focus on the role of noninvasive pressure-based CAFA in screening asymptomatic ischemia-causing carotid stenosis.

TU-H-CAMPUS-IeP3-02: Neurovascular 4D Parametric Imaging Using Co-Registration of Biplane DSA Sequences with 3D Vascular Geometry Obtained From Cone Beam CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balasubramoniam, A; Bednarek, D; Rudin, S

Purpose: To create 4D parametric images using biplane Digital Subtraction Angiography (DSA) sequences co-registered with the 3D vascular geometry obtained from Cone Beam-CT (CBCT). Methods: We investigated a method to derive multiple 4D Parametric Imaging (PI) maps using only one CBCT acquisition. During this procedure a 3D-DSA geometry is stored and used subsequently for all 4D images. Each time a biplane DSA is acquired, we calculate 2D parametric maps of Bolus Arrival Time (BAT), Mean Transit Time (MTT) and Time to Peak (TTP). Arterial segments which are nearly parallel with one of the biplane imaging planes in the 2D parametricmore » maps are co-registered with the 3D geometry. The values in the remaining vascular network are found using spline interpolation since the points chosen for co-registration on the vasculature are discrete and remaining regions need to be interpolated. To evaluate the method we used a patient CT volume data set for 3D printing a neurovascular phantom containing a complete Circle of Willis. We connected the phantom to a flow loop with a peristaltic pump, simulating physiological flow conditions. Contrast media was injected with an automatic injector at 10 ml/sec. Images were acquired with a Toshiba Infinix C-arm and 4D parametric image maps of the vasculature were calculated. Results: 4D BAT, MTT, and TTP parametric image maps of the Circle of Willis were derived. We generated color-coded 3D geometries which avoided artifacts due to vessel overlap or foreshortening in the projection direction. Conclusion: The software was tested successfully and multiple 4D parametric images were obtained from biplane DSA sequences without the need to acquire additional 3D-DSA runs. This can benefit the patient by reducing the contrast media and the radiation dose normally associated with these procedures. Partial support from NIH Grant R01-EB002873 and Toshiba Medical Systems Corp.« less

Overview and development of EDA tools for integration of DSA into patterning solutions

NASA Astrophysics Data System (ADS)

Torres, J. Andres; Fenger, Germain; Khaira, Daman; Ma, Yuansheng; Granik, Yuri; Kapral, Chris; Mitra, Joydeep; Krasnova, Polina; Ait-Ferhat, Dehia

2017-03-01

Directed Self-Assembly is the method by which a self-assembly polymer is forced to follow a desired geometry defined or influenced by a guiding pattern. Such guiding pattern uses surface potentials, confinement or both to achieve polymer configurations that result in circuit-relevant topologies, which can be patterned onto a substrate. Chemo, and grapho epitaxy of lines and space structures are now routinely inspected at full wafer level to understand the defectivity limits of the materials and their maximum resolution. In the same manner, there is a deeper understanding about the formation of cylinders using grapho-epitaxy processes. Academia has also contributed by developing methods that help reduce the number of masks in advanced nodes by "combining" DSA-compatible groups, thus reducing the total cost of the process. From the point of view of EDA, new tools are required when a technology is adopted, and most technologies are adopted when they show a clear cost-benefit over alternative techniques. In addition, years of EDA development have led to the creation of very flexible toolkits that permit rapid prototyping and evaluation of new process alternatives. With the development of high-chi materials, and by moving away of the well characterized PS-PMMA systems, as well as novel integrations in the substrates that work in tandem with diblock copolymer systems, it is necessary to assess any new requirements that may or may not need custom tools to support such processes. Hybrid DSA processes (which contain both chemo and grapho elements), are currently being investigated as possible contenders for sub-5nm process techniques. Because such processes permit the re-distribution of discontinuities in the regular arrays between the substrate and a cut operation, they have the potential to extend the number of applications for DSA. This paper illustrates the reason as to why some DSA processes can be supported by existing rules and technology, while other processes require the development of highly customized correction tools and models. It also illustrates how developing DSA cannot be done in isolation, and it requires the full collaboration of EDA, Material's suppliers, Manufacturing equipment, Metrology, and electronic manufacturers.

Directed self-assembly of poly(styrene)-block-poly(acrylic acid) copolymers for sub-20nm pitch patterning

NASA Astrophysics Data System (ADS)

Cheng, Jing; Lawson, Richard A.; Yeh, Wei-Ming; Jarnagin, Nathan D.; Peters, Andrew; Tolbert, Laren M.; Henderson, Clifford L.

2012-03-01

Directed self-assembly (DSA) of block copolymers is a promising technology for extending the patterning capability of current lithographic exposure tools. For example, production of sub-40 nm pitch features using 193nm exposure technologies is conceivably possible using DSA methods without relying on time consuming, challenging, and expensive multiple patterning schemes. Significant recent work has focused on demonstration of the ability to produce large areas of regular grating structures with low numbers of defects using self-assembly of poly(styrene)-b-poly(methyl methacrylate) copolymers (PS-b-PMMA). While these recent results are promising and have shown the ability to print pitches approaching 20 nm using DSA, the ability to advance to even smaller pitches will be dependent upon the ability to develop new block copolymers with higher χ values and the associated alignment and block removal processes required to achieve successful DSA with these new materials. This paper reports on work focused on identifying higher χ block copolymers and their associated DSA processes for sub-20 nm pitch patterning. In this work, DSA using polystyrene-b-polyacid materials has been explored. Specifically, it is shown that poly(styrene)-b-poly(acrylic acid) copolymers (PS-b-PAA) is one promising material for achieving substantially smaller pitch patterns than those possible with PS-b-PMMA while still utilizing simple hydrocarbon polymers. In fact, it is anticipated that much of the learning that has been done with the PS-b-PMMA system, such as development of highly selective plasma etch block removal procedures, can be directly leveraged or transferred to the PS-b-PAA system. Acetone vapor annealing of PS-b-PAA (Mw=16,000 g/mol with 50:50 mole ratio of PS:PAA) and its self-assembly into a lamellar morphology is demonstrated to generate a pattern pitch size (L0) of 21 nm. The χ value for PS-b-PAA was estimated from fingerprint pattern pitch data to be approximately 0.18 which is roughly 4.5 times greater than the χ for PS-b-PMMA (χPS-b-PMMA ~ 0.04).

Synthesis and electrochemical properties of silicon nanosheets by DC arc discharge for lithium-ion batteries.

PubMed

Yu, Xiuhong; Xue, Fanghong; Huang, Hao; Liu, Chunjing; Yu, Jieyi; Sun, Yuejun; Dong, Xinglong; Cao, Guozhong; Jung, Youngguan

2014-06-21

Two-dimensional (2D) ultrathin silicon nanosheets (Si NSs) were synthesized by DC arc discharge method and investigated as anode material for Li-ion batteries. The 2D ultrathin characteristics of Si NSs is confirmed by means of transmission electron microscopy (TEM) and atomic force microscopy (AFM). The average size of Si NSs is about 20 nm, with thickness less than 2.5 nm. The characteristic Raman peak of Si NSs is found to have an appreciable (20 nm) shift to low frequency, presumably due to the size effect. The synergistic effects of Ar(+) and H(+) lead to 2D growth of Si NSs under high temperature and energy. Electrochemical analyses reveal that Si NSs anode possesses stable cycling performance and fast diffusion of Li-ions with insertion/extraction processes. Such Si NSs might be a promising candidate for anode of Li-ion batteries.

Eutectic Nano-Droplet Template Injection into Bulk Silicon to Construct Porous Frameworks with Concomitant Conformal Coating as Anodes for Li-Ion Batteries

PubMed Central

Qu, Fei; Li, Chilin; Wang, Zumin; Wen, Yuren; Richter, Gunther; Strunk, Horst P.

2015-01-01

Building porosity in monolithic materials is highly desired to design 3D electrodes, however ex-situ introduction or in-situ generation of nano-scale sacrificial template is still a great challenge. Here Al-Si eutectic droplet templates are uniformly injected into bulk Si through Al-induced solid-solid convection to construct a highly porous Si framework. This process is concomitant with process-inherent conformal coating of ion-conductive oxide. Such an all-in-one method has generated a (continuously processed) high-capacity Si anode integrating longevity and stable electrolyte-anode diaphragm for Li-ion batteries (e.g. a reversible capacity as large as ~1800 mAh/g or ~350 μAh/cm2-μm with a CE of ~99% at 0.1 C after long-term 400 cycles). PMID:25988370

Hard-Soft Composite Carbon as a Long-Cycling and High-Rate Anode for Potassium-Ion Batteries

DOE PAGES

Jian, Zelang; Hwang, Sooyeon; Li, Zhifei; ...

2017-05-05

There exist tremendous needs for sustainable storage solutions for intermittent renewable energy sources, such as solar and wind energy. Thus, systems based on Earth-abundant elements deserve much attention. Potassium-ion batteries represent a promising candidate because of the abundance of potassium resources. As for the choices of anodes, graphite exhibits encouraging potassium-ion storage properties; however, it suffers limited rate capability and poor cycling stability. Here in this paper, nongraphitic carbons as K-ion anodes with sodium carboxymethyl cellulose as the binder are systematically investigated. Compared to hard carbon and soft carbon, a hard–soft composite carbon with 20 wt% soft carbon distributed inmore » the matrix phase of hard carbon microspheres exhibits highly amenable performance: high capacity, high rate capability, and very stable long-term cycling. In contrast, pure hard carbon suffers limited rate capability, while the capacity of pure soft carbon fades more rapidly.« less

Pulsed electromagnetic gas accelleration. [incorporation of hollow cathode in plasma discharge and suitability determination of MPD discharge as plasmadynamic laser source

NASA Technical Reports Server (NTRS)

Jahn, R. G.

1973-01-01

Direct measurement with thermocouples of the power deposited in the anode of a multi-megawatt magnetoplasmadynamic discharge has shown the fractional anode power to decrease from 50% at 200 kW to 10% at 20 MW. Using local measurements of current density, electric potential, and electron temperature, the traditional model for heat conduction to the anode is found to be inadequate. Other experiments in which the voltage-current characteristics and exhaust velocities of MPD arcs using Plexiglas and boron nitride chamber insulators and various mass injection configurations show that ablation can affect nominal accelerator operation in several distinct ways. The incorporation of a hollow cathode in a 7 kA plasma discharge has shown that a stable current attachment can be realized in the cavity without the aid of cathode heaters, keeper electrodes, or emissive coatings.

Submicroporous/microporous and compatible/incompatible multi-functional dual-layer polymer electrolytes and their interfacial characteristics with lithium metal anode

NASA Astrophysics Data System (ADS)

Lee, Young-Gi; Kyhm, Kwangseuk; Choi, Nam-Soon; Ryu, Kwang Sun

A novel multi-functional dual-layer polymer electrolyte was prepared by impregnating the interconnected pores with an ethylene carbonate (EC)/dimethyl carbonate (DMC)/lithium hexafluorophosphate (LiPF 6) solution. An incompatible layer is based on a microporous polyethylene (PE) and a compatible layer, based on a poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) is sub-microporous and compatible with an electrolyte solution. The Li electrode/the dual-layer polymer electrolyte/Li[Ni 0.15Li 0.23M n0.62]O 2 cell showed stable cycle performance under prolonged cycle number. This behavior is due to the enhanced compatibility between the matrix polymer and the liquid electrolytes within the submicroporous compatible layer, which could lead to a controlled Li + deposition on the Li anode surface by forming homegeneous electrolyte zone near the anode.

Eutectic nano-droplet template injection into bulk silicon to construct porous frameworks with concomitant conformal coating as anodes for Li-ion batteries.

PubMed

Qu, Fei; Li, Chilin; Wang, Zumin; Wen, Yuren; Richter, Gunther; Strunk, Horst P

2015-05-19

Building porosity in monolithic materials is highly desired to design 3D electrodes, however ex-situ introduction or in-situ generation of nano-scale sacrificial template is still a great challenge. Here Al-Si eutectic droplet templates are uniformly injected into bulk Si through Al-induced solid-solid convection to construct a highly porous Si framework. This process is concomitant with process-inherent conformal coating of ion-conductive oxide. Such an all-in-one method has generated a (continuously processed) high-capacity Si anode integrating longevity and stable electrolyte-anode diaphragm for Li-ion batteries (e.g. a reversible capacity as large as ~1800 mAh/g or ~350 μAh/cm(2)-μm with a CE of ~99% at 0.1 C after long-term 400 cycles).

High performance sandwich structured Si thin film anodes with LiPON coating

NASA Astrophysics Data System (ADS)

Luo, Xinyi; Lang, Jialiang; Lv, Shasha; Li, Zhengcao

2018-06-01

The sandwich structured silicon thin film anodes with lithium phosphorus oxynitride (LiPON) coating are synthesized via the radio frequency magnetron sputtering method, whereas the thicknesses of both layers are in the nanometer range, i.e. between 50 and 200 nm. In this sandwich structure, the separator simultaneously functions as a flexible substrate, while the LiPON layer is regarded as a protective layer. This sandwich structure combines the advantages of flexible substrate, which can help silicon release the compressive stress, and the LiPON coating, which can provide a stable artificial solid-electrolyte interphase (SEI) film on the electrode. As a result, the silicon anodes are protected well, and the cells exhibit high reversible capacity, excellent cycling stability and good rate capability. All the results demonstrate that this sandwich structure can be a promising option for high performance Si thin film lithium ion batteries.

Remarkable cycle-activated capacity increasing in onion-like carbon nanospheres as lithium battery anode material

NASA Astrophysics Data System (ADS)

Dong, Jiajun; Zhang, Tong; Zhang, Dong; Zhang, Weiwei; Zhang, Huafang; Liu, Ran; Yao, Mingguang; Liu, Bingbing

2017-01-01

Onion-like carbon nanospheres (OCNSs) with an average diameter of 43 nm were produced on a large scale via a combustion method and examined as an anode material for lithium ion batteries. The OCNSs exhibit a remarkable electrochemical cycling behavior and a capacity much higher than that of graphite. The capacity increases significantly with increasing charge-discharge cycles and reaches a value of 178% of the initial value (from 586 mA h g-1to 1045 mA h g-1) after 200 cycles. Further investigation provides unambiguous experimental evidence that such a remarkable capacity increase is related to the stable onion-like structure of the OCNSs and to the existence of large numbers of disordered/short graphitic fragments, which gradually provide more active sites for Li ion storage. The unique electrochemical performance of OCNSs provides a new way to design a high-performance anode material for rechargeable batteries.

High performance sandwich structured Si thin film anodes with LiPON coating

NASA Astrophysics Data System (ADS)

Luo, Xinyi; Lang, Jialiang; Lv, Shasha; Li, Zhengcao

2018-04-01

The sandwich structured silicon thin film anodes with lithium phosphorus oxynitride (LiPON) coating are synthesized via the radio frequency magnetron sputtering method, whereas the thicknesses of both layers are in the nanometer range, i.e. between 50 and 200 nm. In this sandwich structure, the separator simultaneously functions as a flexible substrate, while the LiPON layer is regarded as a protective layer. This sandwich structure combines the advantages of flexible substrate, which can help silicon release the compressive stress, and the LiPON coating, which can provide a stable artificial solidelectrolyte interphase (SEI) film on the electrode. As a result, the silicon anodes are protected well, and the cells exhibit high reversible capacity, excellent cycling stability and good rate capability. All the results demonstrate that this sandwich structure can be a promising option for high performance Si thin film lithium ion batteries.

Carbon Cryogel and Carbon Paper-Based Silicon Composite Anode Materials for Lithium-Ion Batteries

NASA Technical Reports Server (NTRS)

Woodworth, James; Baldwin, Richard; Bennett, William

2010-01-01

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 6 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-5 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

Silicon Composite Anode Materials for Lithium Ion Batteries Based on Carbon Cryogels and Carbon Paper

NASA Technical Reports Server (NTRS)

Woodworth, James; Baldwin, Richard; Bennett, William

2010-01-01

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nanofoams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

An advanced lithium-ion battery based on a graphene anode and a lithium iron phosphate cathode.

PubMed

Hassoun, Jusef; Bonaccorso, Francesco; Agostini, Marco; Angelucci, Marco; Betti, Maria Grazia; Cingolani, Roberto; Gemmi, Mauro; Mariani, Carlo; Panero, Stefania; Pellegrini, Vittorio; Scrosati, Bruno

2014-08-13

We report an advanced lithium-ion battery based on a graphene ink anode and a lithium iron phosphate cathode. By carefully balancing the cell composition and suppressing the initial irreversible capacity of the anode in the round of few cycles, we demonstrate an optimal battery performance in terms of specific capacity, that is, 165 mAhg(-1), of an estimated energy density of about 190 Wh kg(-1) and a stable operation for over 80 charge-discharge cycles. The components of the battery are low cost and potentially scalable. To the best of our knowledge, complete, graphene-based, lithium ion batteries having performances comparable with those offered by the present technology are rarely reported; hence, we believe that the results disclosed in this work may open up new opportunities for exploiting graphene in the lithium-ion battery science and development.

Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries

NASA Technical Reports Server (NTRS)

Woodworth James; Baldwin, Richard; Bennett, William

2010-01-01

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

Hard-Soft Composite Carbon as a Long-Cycling and High-Rate Anode for Potassium-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jian, Zelang; Hwang, Sooyeon; Li, Zhifei

There exist tremendous needs for sustainable storage solutions for intermittent renewable energy sources, such as solar and wind energy. Thus, systems based on Earth-abundant elements deserve much attention. Potassium-ion batteries represent a promising candidate because of the abundance of potassium resources. As for the choices of anodes, graphite exhibits encouraging potassium-ion storage properties; however, it suffers limited rate capability and poor cycling stability. Here in this paper, nongraphitic carbons as K-ion anodes with sodium carboxymethyl cellulose as the binder are systematically investigated. Compared to hard carbon and soft carbon, a hard–soft composite carbon with 20 wt% soft carbon distributed inmore » the matrix phase of hard carbon microspheres exhibits highly amenable performance: high capacity, high rate capability, and very stable long-term cycling. In contrast, pure hard carbon suffers limited rate capability, while the capacity of pure soft carbon fades more rapidly.« less

Gate bias stress stability under light irradiation for indium zinc oxide thin-film transistors based on anodic aluminium oxide gate dielectrics

NASA Astrophysics Data System (ADS)

Li, Min; Lan, Linfeng; Xu, Miao; Wang, Lei; Xu, Hua; Luo, Dongxiang; Zou, Jianhua; Tao, Hong; Yao, Rihui; Peng, Junbiao

2011-11-01

Thin-film transistors (TFTs) using indium zinc oxide as the active layer and anodic aluminium oxide (Al2O3) as the gate dielectric layer were fabricated. The device showed an electron mobility of as high as 10.1 cm2 V-1 s-1, an on/off current ratio of as high as ~108, and a turn-on voltage (Von) of only -0.5 V. Furthermore, this kind of TFTs was very stable under positive bias illumination stress. However, when the device experienced negative bias illumination stress, the threshold voltage shifted to the positive direction. It was found that the instability under negative bias illumination stress (NBIS) was due to the electrons from the Al gate trapping into the Al2O3 dielectric when exposed to the illuminated light. Using a stacked structure of Al2O3/SiO2 dielectrics, the device became more stable under NBIS.

Towards the next generation of solid oxide fuel cells operating below 600 °c with chemically stable proton-conducting electrolytes.

PubMed

Fabbri, Emiliana; Bi, Lei; Pergolesi, Daniele; Traversa, Enrico

2012-01-10

The need for reducing the solid oxide fuel cell (SOFC) operating temperature below 600 °C is imposed by cost reduction, which is essential for widespread SOFC use, but might also disclose new applications. To this aim, high-temperature proton-conducting (HTPC) oxides have gained widespread interest as electrolyte materials alternative to oxygen-ion conductors. This Progress Report describes recent developments in electrolyte, anode, and cathode materials for protonic SOFCs, addressing the issue of chemical stability, processability, and good power performance below 600 °C. Different fabrication methods are reported for anode-supported SOFCs, obtained using state-of-the-art, chemically stable proton-conducting electrolyte films. Recent findings show significant improvements in the power density output of cells based on doped barium zirconate electrolytes, pointing out towards the feasibility of the next generation of protonic SOFCs, including a good potential for the development of miniaturized SOFCs as portable power supplies. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Composite of K-doped (NH4)2V3O8/graphene as an anode material for sodium-ion batteries.

PubMed

Liu, Xin; Li, Zhiwei; Fei, Hailong; Wei, Mingdeng

2015-11-21

A layer structured K-doped (NH4)2V3O8/graphene (K-NVG) was prepared via a hydrothermal route and then used as an anode material for sodium-ion batteries for the first time. The K-NVG nanosheets have a diameter in the range of 200-500 nm. The K-NVG electrode exhibited stable cycling and a good rate performance with a reversible capacity of 235.4 mA h g(-1), which is much higher than the 90.5 mA h g(-1) value of the (NH4)2V3O8/graphene electrode after 100 cycles at a current density of 100 mA g(-1). Simultaneously, the retention rate was maintained at 82% even after 250 cycles at the current density of 300 mA g(-1). Such good electrochemical properties may be attributed to the K-NVG's stable layered structure.

Overcoming the Instability of Nanoparticle-Based Catalyst Films in Alkaline Electrolyzers by using Self-Assembling and Self-Healing Films.

PubMed

Barwe, Stefan; Masa, Justus; Andronescu, Corina; Mei, Bastian; Schuhmann, Wolfgang; Ventosa, Edgar

2017-07-10

Engineering stable electrodes using highly active catalyst nanopowders for electrochemical water splitting remains a challenge. We report an innovative and general approach for attaining highly stable catalyst films with self-healing capability based on the in situ self-assembly of catalyst particles during electrolysis. The catalyst particles are added to the electrolyte forming a suspension that is pumped through the electrolyzer. Particles with negatively charged surfaces stick onto the anode, while particles with positively charged surfaces stick to the cathode. The self-assembled catalyst films have self-healing properties as long as sufficient catalyst particles are present in the electrolyte. The proof-of-concept was demonstrated in a non-zero gap alkaline electrolyzer using NiFe-LDH and Ni x B catalyst nanopowders for anode and cathode, respectively. Steady cell voltages were maintained for at least three weeks during continuous electrolysis at 50-100 mA cm -2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of atomic layer deposition coatings on the surface structure of anodic aluminum oxide membranes.

PubMed

Xiong, Guang; Elam, Jeffrey W; Feng, Hao; Han, Catherine Y; Wang, Hsien-Hau; Iton, Lennox E; Curtiss, Larry A; Pellin, Michael J; Kung, Mayfair; Kung, Harold; Stair, Peter C

2005-07-28

Anodic aluminum oxide (AAO) membranes were characterized by UV Raman and FT-IR spectroscopies before and after coating the entire surface (including the interior pore walls) of the AAO membranes by atomic layer deposition (ALD). UV Raman reveals the presence of aluminum oxalate in bulk AAO, both before and after ALD coating with Al2O3, because of acid anion incorporation during the anodization process used to produce AAO membranes. The aluminum oxalate in AAO exhibits remarkable thermal stability, not totally decomposing in air until exposed to a temperature >900 degrees C. ALD was used to cover the surface of AAO with either Al2O3 or TiO2. Uncoated AAO have FT-IR spectra with two separate types of OH stretches that can be assigned to isolated OH groups and hydrogen-bonded surface OH groups, respectively. In contrast, AAO surfaces coated by ALD with Al2O3 display a single, broad band of hydrogen-bonded OH groups. AAO substrates coated with TiO2 show a more complicated behavior. UV Raman results show that very thin TiO2 coatings (1 nm) are not stable upon annealing to 500 degrees C. In contrast, thicker coatings can totally cover the contaminated alumina surface and are stable at temperatures in excess of 500 degrees C.

Efficient electrolyzer for CO2 splitting in neutral water using earth-abundant materials.

PubMed

Tatin, Arnaud; Comminges, Clément; Kokoh, Boniface; Costentin, Cyrille; Robert, Marc; Savéant, Jean-Michel

2016-05-17

Low-cost, efficient CO2-to-CO+O2 electrochemical splitting is a key step for liquid-fuel production for renewable energy storage and use of CO2 as a feedstock for chemicals. Heterogeneous catalysts for cathodic CO2-to-CO associated with an O2-evolving anodic reaction in high-energy-efficiency cells are not yet available. An iron porphyrin immobilized into a conductive Nafion/carbon powder layer is a stable cathode producing CO in pH neutral water with 90% faradaic efficiency. It is coupled with a water oxidation phosphate cobalt oxide anode in a home-made electrolyzer by means of a Nafion membrane. Current densities of approximately 1 mA/cm(2) over 30-h electrolysis are achieved at a 2.5-V cell voltage, splitting CO2 and H2O into CO and O2 with a 50% energy efficiency. Remarkably, CO2 reduction outweighs the concurrent water reduction. The setup does not prevent high-efficiency proton transport through the Nafion membrane separator: The ohmic drop loss is only 0.1 V and the pH remains stable. These results demonstrate the possibility to set up an efficient, low-voltage, electrochemical cell that converts CO2 into CO and O2 by associating a cathodic-supported molecular catalyst based on an abundant transition metal with a cheap, easy-to-prepare anodic catalyst oxidizing water into O2.

Objective criteria for acceptability and constancy tests of digital subtraction angiography.

PubMed

de las Heras, Hugo; Torres, Ricardo; Fernández-Soto, José Miguel; Vañó, Eliseo

2016-01-01

Demonstrate an objective procedure to quantify image quality in digital subtraction angiography (DSA) and suggest thresholds for acceptability and constancy tests. Series of images were obtained in a DSA system simulating a small (paediatric) and a large patient using the dynamic phantom described in the IEC and DIN standards for acceptance tests of DSA equipment. Image quality was quantified using measurements of contrast-to-noise ratio (CNR). Overall scores combining the CNR of 10-100 mg/ml Iodine at a vascular diameter of 1-4 mm in a homogeneous background were defined. Phantom entrance surface air kerma (Ka,e) was measured with an ionisation chamber. The visibility of a low-contrast vessel in DSA images has been identified with a CNR value of 0.50 ± 0.03. Despite using 14 times more Ka,e (8.85 vs 0.63 mGy/image), the protocol for large patients showed a decrease in the overall score CNRsum of 67% (4.21 ± 0.06 vs 2.10 ± 0.05). The uncertainty in the results of the objective method was below 5%. Objective evaluation of DSA images using CNR is feasible with dedicated phantom measurements. An objective methodology has been suggested for acceptance tests compliant with the IEC/DIN standards. The defined overall scores can serve to fix a reproducible baseline for constancy tests, as well as to study the device stability within one acquisition series and compare different imaging protocols. This work provides aspects that have not been included in the recent European guidelines on Criteria for Acceptability of Medical Radiological Equipment. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Detection and characterization of unruptured intracranial aneurysms: Comparison of 3T MRA and DSA.

PubMed

Mine, Benjamin; Pezzullo, Martina; Roque, Gonçalo; David, Philippe; Metens, Thierry; Lubicz, Boris

2015-06-01

To compare magnetic resonance angiography (MRA) at 3 Tesla (3T) and digital subtraction angiography (DSA) for the detection and characterization of unruptured intracranial aneurysms (UIA). This study has been approved by our local ethical committee. From February to August 2010, 40 consecutive patients with UIA contemporarily underwent MRA at 3T including time-of-flight (TOF-MRA) and contrast enhanced (CE-MRA) techniques and DSA. MR images were independently reviewed by 3 radiologists and DSA images were reviewed by 2 radiologists together. Interobserver and intertechnique agreements were assessed for aneurysm detection and characterization including maximal diameter, neck width and the presence of a bleb or a branch arising from the sac. DS angiography revealed 56 aneurysms. Mean sensitivity and positive predictive value of MRA were 91.4% and 93.4% respectively. For UIA < 3 mm and those ≥ 3 mm, MRA had a mean sensitivity of 74.1% and 100% respectively. Intertechnique and interobserver agreements were substantial for the measurement of UIA maximal diameter (mean κ, 0.607 and 0.601 respectively) and were moderate and fair for neck width measurement respectively (mean κ, 0.456 and 0.285 respectively). For bleb detection, intertechnique and interobserver agreements were fair and slight respectively (mean κ, 0.312 and 0.116 respectively) whereas both were slight for detection of branches arising from the sac (mean κ, 0.151 and 0.070 respectively). MR angiography at 3T has a high sensitivity for the detection of UIA. However, it remains significantly inferior to DSA for morphological characterization of UIA. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Nonenhanced peripheral MR-angiography (MRA) at 3 Tesla: evaluation of quiescent-interval single-shot MRA in patients undergoing digital subtraction angiography.

PubMed

Wagner, Moritz; Knobloch, Gesine; Gielen, Martin; Lauff, Marie-Teres; Romano, Valentina; Hamm, Bernd; Kröncke, Thomas

2015-04-01

Quiescent-interval single-shot MRA (QISS-MRA) is a promising nonenhanced imaging technique for assessment of peripheral arterial disease (PAD). Previous studies at 3 Tesla included only very limited numbers of patients for correlation of QISS-MRA with digital subtraction angiography (DSA) as standard of reference (SOR). The aim of this prospective institutional review board-approved study was to compare QISS-MRA at 3 Tesla with DSA in a larger patient group. Our study included 32 consecutive patients who underwent QISS-MRA, contrast-enhanced MRA (CE-MRA), and DSA. Two readers independently performed a per-segment evaluation of QISS-MRA and CE-MRA for image quality and identification of non-significant stenosis (<50%) versus significant stenosis (50-100%). The final dataset included 1,027 vessel segments. Reader 1 and 2 rated image quality as diagnostic in 96.8 and 98.0% of the vessel segments on QISS-MRA and in 99.3 and 98.4% of the vessel segments on CE-MRA, respectively. DSA was available for 922 segments and detected significant stenosis in 133 segments (14.4%). Consensus reading yielded the following diagnostic parameters for QISS-MRA versus CE-MRA: sensitivity: 83.5% (111/133) versus 82.7% (110/133), p = 0.80; specificity: 93.9% (741/789) versus 95.7% (755/789), p = 0.25; and diagnostic accuracy: 92.4% (852/922) versus 93.8% (865/922), p = 0.35. In conclusion, using DSA as SOR, QISS-MRA and CE-MRA at 3 Tesla showed similar diagnostic accuracy in the assessment of PAD. A limitation of QISS-MRA was the lower rate of assessable vessel segments compared to CE-MRA.

Validation of a dye stain assay for vaginally inserted HEC-filled microbicide applicators

PubMed Central

Katzen, Lauren L.; Fernández-Romero, José A.; Sarna, Avina; Murugavel, Kailapuri G.; Gawarecki, Daniel; Zydowsky, Thomas M.; Mensch, Barbara S.

2011-01-01

Background The reliability and validity of self-reports of vaginal microbicide use are questionable given the explicit understanding that participants are expected to comply with study protocols. Our objective was to optimize the Population Council's previously validated dye stain assay (DSA) and related procedures, and establish predictive values for the DSA's ability to identify vaginally inserted single-use, low-density polyethylene microbicide applicators filled with hydroxyethylcellulose gel. Methods Applicators, inserted by 252 female sex workers enrolled in a microbicide feasibility study in Southern India, served as positive controls for optimization and validation experiments. Prior to validation, optimal dye concentration and staining time were ascertained. Three validation experiments were conducted to determine sensitivity, specificity, negative predictive values and positive predictive values. Results The dye concentration of 0.05% (w/v) FD&C Blue No. 1 Granular Food Dye and staining time of five seconds were determined to be optimal and were used for the three validation experiments. There were a total of 1,848 possible applicator readings across validation experiments; 1,703 (92.2%) applicator readings were correct. On average, the DSA performed with 90.6% sensitivity, 93.9% specificity, and had a negative predictive value of 93.8% and a positive predictive value of 91.0%. No statistically significant differences between experiments were noted. Conclusions The DSA was optimized and successfully validated for use with single-use, low-density polyethylene applicators filled with hydroxyethylcellulose (HEC) gel. We recommend including the DSA in future microbicide trials involving vaginal gels in order to identify participants who have low adherence to dosing regimens. In doing so, we can develop strategies to improve adherence as well as investigate the association between product use and efficacy. PMID:21992983

Minimally Invasive Monitoring of Chronic Central Venous Catheter Patency in Mice Using Digital Subtraction Angiography (DSA)

PubMed Central

Figueiredo, Giovanna; Fiebig, Teresa; Kirschner, Stefanie; Nikoubashman, Omid; Kabelitz, Lisa; Othman, Ahmed; Nonn, Andrea; Kramer, Martin; Brockmann, Marc A.

2015-01-01

Background Repetitive administration of medication or contrast agents is frequently performed in mice. The introduction of vascular access mini-ports (VAMP) for mice allows long-term vascular catheterization, hereby eliminating the need for repeated vessel puncture. With catheter occlusion being the most commonly reported complication of chronic jugular vein catheterization, we tested whether digital subtraction angiography (DSA) can be utilized to evaluate VAMP patency in mice. Methods Twenty-three mice underwent catheterization of the jugular vein and subcutaneous implantation of a VAMP. The VAMP was flushed every second day with 50 μL of heparinized saline solution (25 IU/ml). DSA was performed during injection of 100 μL of an iodine based contrast agent using an industrial X-ray inspection system intraoperatively, as well as 7±2 and 14±2 days post implantation. Results DSA allowed localization of catheter tip position, to rule out dislocation, kinking or occlusion of a microcatheter, and to evaluate parent vessel patency. In addition, we observed different ante- and retrograde collateral flow patterns in case of jugular vein occlusion. More exactly, 30% of animals showed parent vessel occlusion after 7±2 days in our setting. At this time point, nevertheless, all VAMPs verified intravascular contrast administration. After 14±2 days, intravascular contrast injection was verified in 70% of the implanted VAMPs, whereas at this point of time 5 animals had died or were sacrificed and in 2 mice parent vessel occlusion hampered intravascular contrast injection. Notably, no occlusion of the catheter itself was observed. Conclusion From our observations we conclude DSA to be a fast and valuable minimally invasive tool for investigation of catheter and parent vessel patency and for anatomical studies of collateral blood flow in animals as small as mice. PMID:26098622

Correlation between carotid bifurcation calcium burden on non-enhanced CT and percentage stenosis, as confirmed by digital subtraction angiography

PubMed Central

Sarikaya, B; Lohman, B; Mckinney, A M; Gadani, S; Irfan, M; Lucato, L

2012-01-01

Objectives Previous evidence supports a direct relationship between the calcium burden (volume) on post-contrast CT with the percent internal carotid artery (ICA) stenosis at the carotid bifurcation. We sought to further investigate this relationship by comparing non-enhanced CT (NECT) and digital subtraction angiography (DSA). Methods 50 patients (aged 41–82 years) were retrospectively identified who had undergone cervical NECT and DSA. A 64-multidetector array CT (MDCT) scanner was utilised and the images reviewed using preset window widths/levels (30/300) optimised to calcium, with the volumes measured via three-dimensional reconstructive software. Stenosis measurements were performed on DSA and luminal diameter stenoses >40% were considered “significant”. Volume thresholds of 0.01, 0.03, 0.06, 0.09 and 0.12 cm3 were utilised and Pearson'S correlation coefficient (r) was calculated to correlate the calcium volume with percent stenosis. Results Of 100 carotid bifurcations, 88 were available and of these 7 were significantly stenotic. The NECT calcium volume moderately correlated with percent stenosis on DSA r=0.53 (p<0.01). A moderate–strong correlation was found between the square root of calcium volume on NECT with percent stenosis on DSA (r=0.60, p<0.01). Via a receiver operating characteristic curve, 0.06 cm3 was determined to be the best threshold (sensitivity 100%, specificity 90.1%, negative predictive value 100% and positive predictive value 46.7%) for detecting significant stenoses. Conclusion This preliminary investigation confirms a correlation between carotid bifurcation calcium volume and percent ICA stenosis and is promising for the optimal threshold for stenosis detection. Future studies could utilise calcium volumes to create a “score” that could predict high grade stenosis. PMID:21896662

Re-exposure to beta cell autoantigens in pancreatic allograft recipients with preexisting beta cell autoantibodies.

PubMed

Mujtaba, Muhammad Ahmad; Fridell, Jonathan; Book, Benita; Faiz, Sara; Sharfuddin, Asif; Wiebke, Eric; Rigby, Mark; Taber, Tim

2015-11-01

Re-exposure to beta cell autoantigens and its relevance in the presence of donor-specific antibodies (DSA) in pancreatic allograft recipients is not well known. Thirty-three patients requiring a pancreas transplant were enrolled in an IRB approved study. They underwent prospective monitoring for DSA and beta cell autoantibody (BCAA) levels to GAD65, insulinoma-associated antigen 2 (IA-2), insulin (micro-IAA [mIAA]), and islet-specific zinc transporter isoform-8 (ZnT8). Twenty-five (75.7%) had pre-transplant BCAA. Twenty had a single antibody (mIAA n = 15, GAD65 n = 5); five had two or more BCAA (GAD65 + mIAA n = 2, GAD65 + mIAA+IA-2 n = 2, GA65 + mIAA+IA-2 + ZnT8 = 1). No changes in GAD65 (p > 0.29), IA-2 (>0.16), and ZnT8 (p > 0.07) were observed between pre-transplant and post-transplant at 6 or 12 months. A decrease in mIAA from pre- to post-6 months (p < 0.0001), 12 months (p < 0.0001), and from post-6 to post-12 months (p = 0.0002) was seen. No new BCAA was observed at one yr. Seven (21.0%) developed de novo DSA. The incidence of DSA was 24% in patients with BCAA vs. 25% in patients without BCAA (p = 0.69). Pancreatic allograft function of patients with vs. without BCAA, and with and without BCAA + DSA was comparable until last follow-up (three yr). Re-exposure to beta cell autoantigens by pancreas transplant may not lead to increased levels or development of new BCAA or pancreatic allograft dysfunction. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Arterial spin labeling MR imaging aids to identify cortical venous drainage of dural arteriovenous fistulas.

PubMed

Kang, Ji Hee; Yun, Tae Jin; Rhim, Jong Kook; Cho, Young Dae; Yoo, Dong Hyun; Yoo, Roh-Eul; Kang, Koung Mi; Choi, Seung Hong; Kim, Ji-Hoon; Sohn, Chul-Ho; Han, Moon Hee

2018-05-01

Cortical venous drainage (CVD) increases the probability of intracranial hemorrhage and mortality rate of dural arteriovenous fistulas (DAVF). Although digital subtraction angiography (DSA) is the most accurate method to determine CVD in DAVFs, this modality has limitations due to its invasive nature and radiation issues. The purpose of this study was to evaluate the diagnostic utility of arterial spin-labeling perfusion-weighted images (ASL-PWI) to identify CVD in patients with DAVF.The Institutional Review Board of our hospital approved this retrospective study. ASL-PWI features of 22 patients with DAVF were retrospectively reviewed for the presence of bright signal intensity in cortical veins and brain parenchyma. DAVF with bright signal intensity in cortical veins and/or brain parenchyma was regarded as having CVD. Using DSA as a reference standard, sensitivity, specificity, positive predictive value, and negative predictive value of ASL-PWI for detecting CVD were calculated.Based on DSA features, 11 (11/22, 50%) patients were classified as having "aggressive" pattern with CVD. Eleven (11/22, 50%) patients also showed bright signal intensity in cortical veins (9/22, 41%) and/or brain parenchyma (4/22, 18%) on ASL-PWI. The 11 patients who had "Aggressive" pattern on DSA were the same 11 patients who were classified as having "aggressive" pattern on ASL-PWI. ASL-PWI showed perfect diagnostic performance for identifying CVD with sensitivity, specificity, positive predictive value, and negative predictive value of 100% for all.Thus, ASL-PWI could be used as a noninvasive mean to predict the presence of CVD in patients with DAVFs. It has the potential as a screening tool to evaluate DAVF prior to invasive DSA.

Electrochemical performance and interfacial investigation on Si composite anode for lithium ion batteries in full cell

NASA Astrophysics Data System (ADS)

Shobukawa, Hitoshi; Alvarado, Judith; Yang, Yangyuchen; Meng, Ying Shirley

2017-08-01

Lithium ion batteries (LIBs) containing silicon (Si) as a negative electrode have gained much attention recently because they deliver high energy density. However, the commercialization of LIBs with Si anode is limited due to the unstable electrochemical performance associated with expansion and contraction during electrochemical cycling. This study investigates the electrochemical performance and degradation mechanism of a full cell containing Si composite anode and LiFePO4 (lithium iron phosphate (LFP)) cathode. Enhanced electrochemical cycling performance is observed when the full cell is cycled with fluoroethylene carbonate (FEC) additive compared to the standard electrolyte. To understand the improvement in the electrochemical performance, x-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) are used. Based on the electrochemical behavior, FEC improves the reversibility of lithium ion diffusion into the solid electrolyte interphase (SEI) on the Si composite anode. Moreover, XPS analysis demonstrates that the SEI composition generated from the addition of FEC consists of a large amount of LiF and less carbonate species, which leads to better capacity retention over 40 cycles. The effective SEI successively yields more stable capacity retention and enhances the reversibility of lithium ion diffusion through the interphase of the Si anode, even at higher discharge rate. This study contributes to a basic comprehension of electrochemical performance and SEI formation of LIB full cells with a high loading Si composite anode.

High-Capacity and Long-Cycle Life Aqueous Rechargeable Lithium-Ion Battery with the FePO4 Anode.

PubMed

Wang, Yuesheng; Yang, Shi-Ze; You, Ya; Feng, Zimin; Zhu, Wen; Gariépy, Vincent; Xia, Jiexiang; Commarieu, Basile; Darwiche, Ali; Guerfi, Abdelbast; Zaghib, Karim

2018-02-28

Aqueous lithium-ion batteries are emerging as strong candidates for a great variety of energy storage applications because of their low cost, high-rate capability, and high safety. Exciting progress has been made in the search for anode materials with high capacity, low toxicity, and high conductivity; yet, most of the anode materials, because of their low equilibrium voltages, facilitate hydrogen evolution. Here, we show the application of olivine FePO 4 and amorphous FePO 4 ·2H 2 O as anode materials for aqueous lithium-ion batteries. Their capacities reached 163 and 82 mA h/g at a current rate of 0.2 C, respectively. The full cell with an amorphous FePO 4 ·2H 2 O anode maintained 92% capacity after 500 cycles at a current rate of 0.2 C. The acidic aqueous electrolyte in the full cells prevented cathodic oxygen evolution, while the higher equilibrium voltage of FePO 4 avoided hydrogen evolution as well, making them highly stable. A combination of in situ X-ray diffraction analyses and computational studies revealed that olivine FePO 4 still has the biphase reaction in the aqueous electrolyte and that the intercalation pathways in FePO 4 ·2H 2 O form a 2-D mesh. The low cost, high safety, and outstanding electrochemical performance make the full cells with olivine or amorphous hydrated FePO 4 anodes commercially viable configurations for aqueous lithium-ion batteries.

Tilted Liquid Crystal Alignment on Asymmetrically Grooved Porous Alumina Film

NASA Astrophysics Data System (ADS)

Maeda, Tsuyoshi; Hiroshima, Kohki

2005-06-01

This paper reports the achievement of tilted liquid crystal (LC) alignment on an anodic porous alumina (APA) film using microgrooves with asymmetric shapes and dozens of minute pores. The microgrooves with asymmetric shapes were formed by a rubbing technique. The minute pores were then produced by anodization. The LC pretilt angle was controlled by the shapes of the microgrooves and pores. The LC director was orientated in the same inclining direction as that of a rubbed polyimide (PI) film. The pretilt angle was in the range of 20 to 90°. This tilted LC alignment remains very stable against external forces such as thermal shock and intense light.

Angular Multigrid Preconditioner for Krylov-Based Solution Techniques Applied to the Sn Equations with Highly Forward-Peaked Scattering

NASA Astrophysics Data System (ADS)

Turcksin, Bruno; Ragusa, Jean C.; Morel, Jim E.

2012-01-01

It is well known that the diffusion synthetic acceleration (DSA) methods for the Sn equations become ineffective in the Fokker-Planck forward-peaked scattering limit. In response to this deficiency, Morel and Manteuffel (1991) developed an angular multigrid method for the 1-D Sn equations. This method is very effective, costing roughly twice as much as DSA per source iteration, and yielding a maximum spectral radius of approximately 0.6 in the Fokker-Planck limit. Pautz, Adams, and Morel (PAM) (1999) later generalized the angular multigrid to 2-D, but it was found that the method was unstable with sufficiently forward-peaked mappings between the angular grids. The method was stabilized via a filtering technique based on diffusion operators, but this filtering also degraded the effectiveness of the overall scheme. The spectral radius was not bounded away from unity in the Fokker-Planck limit, although the method remained more effective than DSA. The purpose of this article is to recast the multidimensional PAM angular multigrid method without the filtering as an Sn preconditioner and use it in conjunction with the Generalized Minimal RESidual (GMRES) Krylov method. The approach ensures stability and our computational results demonstrate that it is also significantly more efficient than an analogous DSA-preconditioned Krylov method.

Exploration of suitable dry etch technologies for directed self-assembly

NASA Astrophysics Data System (ADS)

Yamashita, Fumiko; Nishimura, Eiichi; Yatsuda, Koichi; Mochiki, Hiromasa; Bannister, Julie

2012-03-01

Directed self-assembly (DSA) has shown the potential to replace traditional resist patterns and provide a lower cost alternative for sub-20-nm patterns. One of the possible roadblocks for DSA implementation is the ability to etch the polymers to produce quality masks for subsequent etch processes. We have studied the effects of RF frequency and etch chemistry for dry developing DSA patterns. The results of the study showed a capacitively-coupled plasma (CCP) reactor with very high frequency (VHF) had superior pattern development after the block co-polymer (BCP) etch. The VHF CCP demonstrated minimal BCP height loss and line edge roughness (LER)/line width roughness (LWR). The advantage of CCP over ICP is the low dissociation so the etch rate of BCP is maintained low enough for process control. Additionally, the advantage of VHF is the low electron energy with a tight ion energy distribution that enables removal of the polymethyl methacrylate (PMMA) with good selectivity to polystyrene (PS) and minimal LER/LWR. Etch chemistries were evaluated on the VHF CCP to determine ability to treat the BCPs to increase etch resistance and feature resolution. The right combination of RF source frequencies and etch chemistry can help overcome the challenges of using DSA patterns to create good etch results.

Blood flow quantification using 1D CFD parameter identification

NASA Astrophysics Data System (ADS)

Brosig, Richard; Kowarschik, Markus; Maday, Peter; Katouzian, Amin; Demirci, Stefanie; Navab, Nassir

2014-03-01

Patient-specific measurements of cerebral blood flow provide valuable diagnostic information concerning cerebrovascular diseases rather than visually driven qualitative evaluation. In this paper, we present a quantitative method to estimate blood flow parameters with high temporal resolution from digital subtraction angiography (DSA) image sequences. Using a 3D DSA dataset and a 2D+t DSA sequence, the proposed algorithm employs a 1D Computational Fluid Dynamics (CFD) model for estimation of time-dependent flow values along a cerebral vessel, combined with an additional Advection Diffusion Equation (ADE) for contrast agent propagation. The CFD system, followed by the ADE, is solved with a finite volume approximation, which ensures the conservation of mass. Instead of defining a new imaging protocol to obtain relevant data, our cost function optimizes the bolus arrival time (BAT) of the contrast agent in 2D+t DSA sequences. The visual determination of BAT is common clinical practice and can be easily derived from and be compared to values, generated by a 1D-CFD simulation. Using this strategy, we ensure that our proposed method fits best to clinical practice and does not require any changes to the medical work flow. Synthetic experiments show that the recovered flow estimates match the ground truth values with less than 12% error in the mean flow rates.

Electrochemical performance and carbon deposition resistance of M-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (M = Pd, Cu, Ni or NiCu) anodes for solid oxide fuel cells

PubMed Central

Li, Meng; Hua, Bin; Pu, Jian; Chi, Bo; Jian, Li

2015-01-01

Pd-, Cu-, Ni- and NiCu-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ anodes, designated as M-BZCYYb, were prepared by impregnating M-containing solution into BZCYYb scaffold, and investigated in the aspects of electrocatalytic activity for the reactions of H2 and CH4 oxidation and the resistance to carbon deposition. Impregnation of Pd, Ni or NiCu significantly reduced both the ohmic (RΩ) and polarization (RP) losses of BZCYYb anode exposed to H2 or CH4, while Cu impregnation decreased only RΩ in H2 and the both in CH4. Pd-, Ni- and NiCu-BZCYYb anodes were resistant to carbon deposition in wet (3 mol. % H2O) CH4 at 750°C. Deposited carbon fibers were observed in Pd- and Ni-BZCYYb anodes exposed to dry CH4 at 750°C for 12 h, and not observed in NiCu-BZCYYb exposed to dry CH4 at 750°C for 24 h. The performance of a full cell with NiCu-BZCYYb anode, YSZ electrolyte and La0.6Sr0.4Co0.2Fe0.8O3-δ-Gd doped CeO2 (LSCF-GDC) cathode was stable at 750°C in wet CH4 for 130 h, indicating that NiCu-BZCYYb is a promising anode for direct CH4 solid oxide fuel cells (SOFCs). PMID:25563843

Advanced oxidation of real sulfamethoxazole + trimethoprim formulations using different anodes and electrolytes.

PubMed

Murillo-Sierra, Juan C; Sirés, Ignasi; Brillas, Enric; Ruiz-Ruiz, Edgar J; Hernández-Ramírez, Aracely

2018-02-01

A commercial sulfamethoxazole + trimethoprim formulation has been degraded in 0.050 M Na 2 SO 4 at pH 3.0 by electrochemical oxidation with electrogenerated H 2 O 2 (EO-H 2 O 2 ), electro-Fenton (EF), photoelectro-Fenton with a 6-W UVA lamp (PEF) and solar photoelectro-Fenton (SPEF). The tests were performed in an undivided cell with an IrO 2 -based, Pt or boron-doped diamond (BDD) anode and an air-diffusion cathode for H 2 O 2 electrogeneration. The anode material had little effect on the accumulated H 2 O 2 concentration. Both drugs always obeyed a pseudo-first-order decay with low apparent rate constant in EO-H 2 O 2 . Much higher values were found in EF, PEF and SPEF, showing no difference because the main oxidant was always OH formed from Fenton's reaction between H 2 O 2 and added Fe 2+ . The solution mineralization increased in the sequence EO-H 2 O 2  < EF < PEF < SPEF regardless of the anode. The IrO 2 -based and Pt anodes behaved similarly but BDD was always more powerful. In SPEF, similar mineralization profiles were found for all anodes because of the rapid removal of photoactive intermediates by sunlight. About 87% mineralization was obtained as maximum for the powerful SPEF with BDD anode. Addition of Cl - enhanced the decay of both drugs due to their quicker reaction with generated active chlorine, but the formation of persistent chloroderivatives decelerated the mineralization process. Final carboxylic acids like oxalic and oxamic were detected, yielding Fe(III) complexes that remained stable in EF with BDD but were rapidly photolyzed in SPEF with BDD, explaining its superior mineralization ability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Superhierarchical Cobalt-Embedded Nitrogen-Doped Porous Carbon Nanosheets as Two-in-One Hosts for High-Performance Lithium-Sulfur Batteries.

PubMed

Liu, Shaohong; Li, Jia; Yan, Xue; Su, Quanfei; Lu, Yuheng; Qiu, Jieshan; Wang, Zhiyu; Lin, Xidong; Huang, Junlong; Liu, Ruliang; Zheng, Bingna; Chen, Luyi; Fu, Ruowen; Wu, Dingcai

2018-03-01

Lithium-sulfur (Li-S) batteries, based on the redox reaction between elemental sulfur and lithium metal, have attracted great interest because of their inherently high theoretical energy density. However, the severe polysulfide shuttle effect and sluggish reaction kinetics in sulfur cathodes, as well as dendrite growth in lithium-metal anodes are great obstacles for their practical application. Herein, a two-in-one approach with superhierarchical cobalt-embedded nitrogen-doped porous carbon nanosheets (Co/N-PCNSs) as stable hosts for both elemental sulfur and metallic lithium to improve their performance simultaneously is reported. Experimental and theoretical results reveal that stable Co nanoparticles, elaborately encapsulated by N-doped graphitic carbon, can work synergistically with N heteroatoms to reserve the soluble polysulfides and promote the redox reaction kinetics of sulfur cathodes. Moreover, the high-surface-area pore structure and the Co-enhanced lithiophilic N heteroatoms in Co/N-PCNSs can regulate metallic lithium plating and successfully suppress lithium dendrite growth in the anodes. As a result, a full lithium-sulfur cell constructed with Co/N-PCNSs as two-in-one hosts demonstrates excellent capacity retention with stable Coulombic efficiency. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Estimation and Coordination of Sequence Patterns for Frequency Hopping Dynamic Spectrum Access Networks

DTIC Science & Technology

2014-03-27

Technology (AFIT). Research at AFIT investigates the use of DSA for both civilian and military applications while advancing technology in the area of radio...other military platforms is vital for successful operations. Twelve core functions comprise the US Air Force: Nuclear Deterrence Operations, Special...problems. This Air Force report discusses “Frequency Agile Spectrum Utilization”, a sub-topic of DSA, as a potential capability area [3]. Military

Verification of directed self-assembly (DSA) guide patterns through machine learning

NASA Astrophysics Data System (ADS)

Shim, Seongbo; Cai, Sibo; Yang, Jaewon; Yang, Seunghune; Choi, Byungil; Shin, Youngsoo

2015-03-01

Verification of full-chip DSA guide patterns (GPs) through simulations is not practical due to long runtime. We develop a decision function (or functions), which receives n geometry parameters of a GP as inputs and predicts whether the GP faithfully produces desired contacts (good) or not (bad). We take a few sample GPs to construct the function; DSA simulations are performed for each GP to decide whether it is good or bad, and the decision is marked in n-dimensional space. The hyper-plane that separates good marks and bad marks in that space is determined through machine learning process, and corresponds to our decision function. We try a single global function that can be applied to any GP types, and a series of functions in which each function is customized for different GP type; they are then compared and assessed in 10nm technology.

[Affine transformation-based automatic registration for peripheral digital subtraction angiography (DSA)].

PubMed

Kong, Gang; Dai, Dao-Qing; Zou, Lu-Min

2008-07-01

In order to remove the artifacts of peripheral digital subtraction angiography (DSA), an affine transformation-based automatic image registration algorithm is introduced here. The whole process is described as follows: First, rectangle feature templates are constructed with their centers of the extracted Harris corners in the mask, and motion vectors of the central feature points are estimated using template matching technology with the similarity measure of maximum histogram energy. And then the optimal parameters of the affine transformation are calculated with the matrix singular value decomposition (SVD) method. Finally, bilinear intensity interpolation is taken to the mask according to the specific affine transformation. More than 30 peripheral DSA registrations are performed with the presented algorithm, and as the result, moving artifacts of the images are removed with sub-pixel precision, and the time consumption is less enough to satisfy the clinical requirements. Experimental results show the efficiency and robustness of the algorithm.

Interstellar Pickup Ion Acceleration in the Turbulent Magnetic Field at the Solar Wind Termination Shock Using a Focused Transport Approach

NASA Astrophysics Data System (ADS)

Ye, Junye; le Roux, Jakobus A.; Arthur, Aaron D.

2016-08-01

We study the physics of locally born interstellar pickup proton acceleration at the nearly perpendicular solar wind termination shock (SWTS) in the presence of a random magnetic field spiral angle using a focused transport model. Guided by Voyager 2 observations, the spiral angle is modeled with a q-Gaussian distribution. The spiral angle fluctuations, which are used to generate the perpendicular diffusion of pickup protons across the SWTS, play a key role in enabling efficient injection and rapid diffusive shock acceleration (DSA) when these particles follow field lines. Our simulations suggest that variation of both the shape (q-value) and the standard deviation (σ-value) of the q-Gaussian distribution significantly affect the injection speed, pitch-angle anisotropy, radial distribution, and the efficiency of the DSA of pickup protons at the SWTS. For example, increasing q and especially reducing σ enhances the DSA rate.

Advanced fast 3D DSA model development and calibration for design technology co-optimization

NASA Astrophysics Data System (ADS)

Lai, Kafai; Meliorisz, Balint; Muelders, Thomas; Welling, Ulrich; Stock, Hans-Jürgen; Marokkey, Sajan; Demmerle, Wolfgang; Liu, Chi-Chun; Chi, Cheng; Guo, Jing

2017-04-01

Direct Optimization (DO) of a 3D DSA model is a more optimal approach to a DTCO study in terms of accuracy and speed compared to a Cahn Hilliard Equation solver. DO's shorter run time (10X to 100X faster) and linear scaling makes it scalable to the area required for a DTCO study. However, the lack of temporal data output, as opposed to prior art, requires a new calibration method. The new method involves a specific set of calibration patterns. The calibration pattern's design is extremely important when temporal data is absent to obtain robust model parameters. A model calibrated to a Hybrid DSA system with a set of device-relevant constructs indicates the effectiveness of using nontemporal data. Preliminary model prediction using programmed defects on chemo-epitaxy shows encouraging results and agree qualitatively well with theoretical predictions from a strong segregation theory.

Selective directed self-assembly of coexisting morphologies using block copolymer blends

NASA Astrophysics Data System (ADS)

Stein, A.; Wright, G.; Yager, K. G.; Doerk, G. S.; Black, C. T.

2016-08-01

Directed self-assembly (DSA) of block copolymers is an emergent technique for nano-lithography, but is limited in the range of structures possible in a single fabrication step. Here we expand on traditional DSA chemical patterning. A blend of lamellar- and cylinder-forming block copolymers assembles on specially designed surface chemical line gratings, leading to the simultaneous formation of coexisting ordered morphologies in separate areas of the substrate. The competing energetics of polymer chain distortions and chemical mismatch with the substrate grating bias the system towards either line/space or dot array patterns, depending on the pitch and linewidth of the prepattern. This is in contrast to the typical DSA, wherein assembly of a single-component block copolymer on chemical templates generates patterns of either lines/spaces (lamellar) or hexagonal dot arrays (cylinders). In our approach, the chemical template encodes desired local spatial arrangements of coexisting design motifs, self-assembled from a single, sophisticated resist.

Magnetic Resonance Imaging (MRI) and Digital Subtraction Angiography Investigation of Childhood Moyamoya Disease.

PubMed

Song, Peiji; Qin, Jing; Lun, Han; Qiao, Penggang; Xie, Anming; Li, Gongjie

2017-11-01

Because digital subtraction angiography (DSA) is not an ideal angiographic examination for moyamoya disease in the pediatric population, magnetic resonance angiography (MRA) provides a noninvasive contrast-free angiographic examination; whereas magnetic resonance imaging (MRI) provides superior spatial resolution and soft-tissue contrast for lesion assessment. Ninety patients with moyamoya disease were examined by MRI and DSA to assess the distribution of lesions and their diagnostic agreement between modalities. MRI examination revealed 439 lesions. Punctate lesions were the most abundant, followed by patchy lesions. These lesions generally covered a smaller area than the abnormal-vascular corresponding brain parenchyma. Steno-occlusive changes at bilateral anterior, medial, and posterior cerebral arteries were identified by MRA and DSA. MRI showed moderate agreement in identifying lesions after steno-occlusive changes in anterior and medial cerebral arteries, and good agreement in posterior cerebral arteries; 6% to 11% of cases were misdiagnosed by MRA.

Serrated Flow and Dynamic Strain Aging in Fe-Mn-C TWIP Steel

NASA Astrophysics Data System (ADS)

Lan, Peng; Zhang, Jiaquan

2018-01-01

The tensile behavior, serrated flow, and dynamic strain aging of Fe-(20 to 24)Mn-(0.4 to 0.6)C twinning-induced plasticity (TWIP) steel have been investigated. A mathematical approach to analyze the DSA and PLC band parameters has been developed. For Fe-(20 to 24)Mn-(0.4 to 0.6)C TWIP steel with a theoretical ordering index (TOI) between 0.1 and 0.3, DSA can occur at the very beginning of plastic deformation and provide serrations during work hardening, while for TOI less than 0.1 the occurrence of DSA is delayed and twinning-dominant work hardening remains relatively smooth. The critical strain for the onset of DSA and PLC bands in Fe-Mn-C TWIP steels decreases as C content increases, while the numbers of serrations and bands increase. As Mn content increases, the critical strain for DSA and PLC band varies irregularly, but the numbers of serrations and bands increase. For Fe-(20 to 24)Mn-(0.4 to 0.6)C TWIP steel with grain size of about 10 to 20 μm, the twinning-induced work hardening rate is about 2.5 to 3.0 GPa, while the DSA-dominant hardening rate is about 2.0 GPa on average. With increasing engineering strain from 0.01 to 0.55 at an applied strain rate of 0.001s-1, the cycle time for PLC bands in Fe-Mn-C TWIP steel increases from 6.5 to 162 seconds, while the band velocity decreases from 4.5 to 0.5 mm s-1, and the band strain increases from 0.005 to 0.08. Increasing applied strain rate leads to a linear increase of band velocity despite composition differences. In addition, the influence of the Mn and C content on the tensile properties of Fe-Mn-C TWIP steel has been also studied. As C content increases, the yield strength and tensile strength of Fe-Mn-C TWIP steel increase, but the total elongation variation against C content is dependent on Mn content. As Mn content increases, the yield strength and tensile strength decrease, while the total elongation increases, despite C content. Taking both tensile properties and serrated flow behavior into consideration, Fe-22Mn-0.4C TWIP steel shows excellent mechanical performance with a high product of tensile strength and total elongation and a slightly serrated stress-strain response. To suppress the negative effect of DSA in Fe-Mn-C TWIP steels on the stability of tensile behavior, a TOI lower than 0.1 is strongly suggested.

Relative threshold of detection of active arterial bleeding: in vitro comparison of MDCT and digital subtraction angiography.

PubMed

Roy-Choudhury, Shuvro H; Gallacher, David J; Pilmer, John; Rankin, Sheila; Fowler, Geoff; Steers, Jeff; Dourado, Renato; Woodburn, Paul; Adam, Andreas

2007-11-01

The objective of our study was to determine the relative sensitivity and the lowest threshold of bleeding detectable with digital subtraction angiography (DSA) and with MDCT using an in vitro physiologic system. A closed pulsatile cardiopulmonary bypass circuit was connected to tubes traversing a water bath to simulate the abdominal aorta and inferior vena cava. Three smaller interconnecting acrylic plastic tubes were connected as branches to the aortic tubing to simulate branch vessels. One of the three tubes, the control, had no holes in it, one had a 100-microm hole, and one had a 280-microm hole. The leakage rates were predetermined with a cardiac output of 2 and 4 L/min and with a mean arterial pressure (MAP) ranging from 30 to 100 mm Hg for each hole size. The following studies were performed for each of the predetermined leakage rates. For study 1, 16-MDCT was performed using bolus tracking after 35 mL of contrast medium had been injected into a simulated peripheral vein. For study 2, DSA was performed using a 4-French straight catheter placed 10 cm proximal to the holes (selective first aortic branch cannulation). For study 3, DSA was performed with a catheter placed in the small branch at the site of the hole (highly superselective). For study 4, 16-MDCT was performed with a catheter placed as in study 2, 10 cm proximal to the holes, for the detection of lower leakage rates. Cine loops of MDCT and DSA images were examined by two blinded observers to detect extravasation from the holes in the tubes (i.e., the branch arteries). Interobserver agreement was studied using Cohen's kappa statistic. The threshold to detect bleeding was as follows for each study: For IV contrast-enhanced MDCT (study 1), it was 0.35 mL/min; DSA with a catheter 10 cm proximal to the holes (study 2), 0.96 mL/min; DSA with a catheter at the holes (study 3), 0.05 mL/min [corrected] or lower; and intraarterial selective MDCT (study 4), 0.05 mL/min [corrected] or lower. The ease of detection improved with increasing MAPs and larger volumes of leakage. Interobserver correlation was excellent. In vitro, i.v. contrast-enhanced MDCT is more sensitive than first-order aortic branch-selective DSA in detecting active hemorrhage unless the catheter position is highly superselective and is close to the bleeding artery. These results suggest that MDCT can be used as the initial imaging technique in the diagnosis of active hemorrhage if the clinical condition of the patient allows.

Quantitative coronary angiography using image recovery techniques for background estimation in unsubtracted images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Jerry T.; Kamyar, Farzad; Molloi, Sabee

2007-10-15

Densitometry measurements have been performed previously using subtracted images. However, digital subtraction angiography (DSA) in coronary angiography is highly susceptible to misregistration artifacts due to the temporal separation of background and target images. Misregistration artifacts due to respiration and patient motion occur frequently, and organ motion is unavoidable. Quantitative densitometric techniques would be more clinically feasible if they could be implemented using unsubtracted images. The goal of this study is to evaluate image recovery techniques for densitometry measurements using unsubtracted images. A humanoid phantom and eight swine (25-35 kg) were used to evaluate the accuracy and precision of the followingmore » image recovery techniques: Local averaging (LA), morphological filtering (MF), linear interpolation (LI), and curvature-driven diffusion image inpainting (CDD). Images of iodinated vessel phantoms placed over the heart of the humanoid phantom or swine were acquired. In addition, coronary angiograms were obtained after power injections of a nonionic iodinated contrast solution in an in vivo swine study. Background signals were estimated and removed with LA, MF, LI, and CDD. Iodine masses in the vessel phantoms were quantified and compared to known amounts. Moreover, the total iodine in left anterior descending arteries was measured and compared with DSA measurements. In the humanoid phantom study, the average root mean square errors associated with quantifying iodine mass using LA and MF were approximately 6% and 9%, respectively. The corresponding average root mean square errors associated with quantifying iodine mass using LI and CDD were both approximately 3%. In the in vivo swine study, the root mean square errors associated with quantifying iodine in the vessel phantoms with LA and MF were approximately 5% and 12%, respectively. The corresponding average root mean square errors using LI and CDD were both 3%. The standard deviations in the differences between measured iodine mass in left anterior descending arteries using DSA and LA, MF, LI, or CDD were calculated. The standard deviations in the DSA-LA and DSA-MF differences (both {approx}21 mg) were approximately a factor of 3 greater than that of the DSA-LI and DSA-CDD differences (both {approx}7 mg). Local averaging and morphological filtering were considered inadequate for use in quantitative densitometry. Linear interpolation and curvature-driven diffusion image inpainting were found to be effective techniques for use with densitometry in quantifying iodine mass in vitro and in vivo. They can be used with unsubtracted images to estimate background anatomical signals and obtain accurate densitometry results. The high level of accuracy and precision in quantification associated with using LI and CDD suggests the potential of these techniques in applications where background mask images are difficult to obtain, such as lumen volume and blood flow quantification using coronary arteriography.« less

High-Performance Cells Containing Lithium Metal Anodes, LiNi0.6Co0.2Mn0.2O2 (NCM 622) Cathodes, and Fluoroethylene Carbonate-Based Electrolyte Solution with Practical Loading.

PubMed

Salitra, Gregory; Markevich, Elena; Afri, Michal; Talyosef, Yosef; Hartmann, Pascal; Kulisch, Joern; Sun, Yang-Kook; Aurbach, Doron

2018-06-13

We report on the highly stable lithium metal|LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM 622) cells with practical electrodes' loading of 3.3 mA h g -1 , which can undergo many hundreds of stable cycles, demonstrating high rate capability. A key issue was the use of fluoroethylene carbonate (FEC)-based electrolyte solutions (1 M LiPF 6 in FEC/dimethyl carbonate). Li|NCM 622 cells can be cycled at 1.5 mA cm -2 for more than 600 cycles, whereas symmetric Li|Li cells demonstrate stable performance for more than 1000 cycles even at higher areal capacity and current density. We attribute the excellent performance of both Li|NCM and Li|Li cells to the formation of a stable and efficient solid electrolyte interphase (SEI) on the surface of the Li metal electrodes cycled in FEC-based electrolyte solutions. The composition of the SEI on the Li and the NCM electrodes is analyzed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. A drastic capacity fading of Li|NCM cells is observed, followed by spontaneous capacity recovery during prolonged cycling. This phenomenon depends on the current density and the amount of the electrolyte solution and relates to kinetic limitations because of SEI formation on the Li anodes in the FEC-based electrolyte solution.

Tin Oxynitride Anodes by Atomic Layer Deposition for Solid-State Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, David M.; Pearse, Alexander J.; Kim, Nam S.

Major advances in thin-film solid-state batteries (TFSSBs) may capitalize on 3D structuring using high-aspect-ratio substrates such as nanoscale pits, pores, trenches, flexible polymers, and textiles. This will require conformal processes such as atomic layer deposition (ALD) for every active functional component of the battery. In this paper, we explore the deposition and electrochemical properties of SnO 2, SnN y, and SnO xN y thin films as TFSSB anode materials, grown by ALD using tetrakisdimethylamido(tin), H 2O, and N 2 plasma as precursors. By controlling the dose ratio between H 2O and N 2, the N–O fraction can be tuned betweenmore » 0% N and 95% N. The electrochemical properties of these materials were tested across a composition range varying from pure SnO 2, to SnON intermediates, and pure SnNy. In TFSSBs, the SnNy anodes are found to be more stable during cycling than the SnO 2 or SnO xN y films, with an initial reversible capacity beyond that of Li–Sn alloying, retaining 75% of their capacity over 200 cycles compared to only 50% for SnO 2. Lastly, the performance of the SnO xN y anodes indicates that SnN y anodes should not be negatively impacted by small levels of O contamination.« less

3D Microstructure Effects in Ni-YSZ Anodes: Prediction of Effective Transport Properties and Optimization of Redox Stability

PubMed Central

Pecho, Omar M.; Stenzel, Ole; Iwanschitz, Boris; Gasser, Philippe; Neumann, Matthias; Schmidt, Volker; Prestat, Michel; Hocker, Thomas; Flatt, Robert J.; Holzer, Lorenz

2015-01-01

This study investigates the influence of microstructure on the effective ionic and electrical conductivities of Ni-YSZ (yttria-stabilized zirconia) anodes. Fine, medium, and coarse microstructures are exposed to redox cycling at 950 °C. FIB (focused ion beam)-tomography and image analysis are used to quantify the effective (connected) volume fraction (Φeff), constriction factor (β), and tortuosity (τ). The effective conductivity (σeff) is described as the product of intrinsic conductivity (σ0) and the so-called microstructure-factor (M): σeff = σ0 × M. Two different methods are used to evaluate the M-factor: (1) by prediction using a recently established relationship, Mpred = εβ0.36/τ5.17, and (2) by numerical simulation that provides conductivity, from which the simulated M-factor can be deduced (Msim). Both methods give complementary and consistent information about the effective transport properties and the redox degradation mechanism. The initial microstructure has a strong influence on effective conductivities and their degradation. Finer anodes have higher initial conductivities but undergo more intensive Ni coarsening. Coarser anodes have a more stable Ni phase but exhibit lower YSZ stability due to lower sintering activity. Consequently, in order to improve redox stability, it is proposed to use mixtures of fine and coarse powders in different proportions for functional anode and current collector layers. PMID:28793523

Tin Oxynitride Anodes by Atomic Layer Deposition for Solid-State Batteries

DOE PAGES

Stewart, David M.; Pearse, Alexander J.; Kim, Nam S.; ...

2018-03-30

Major advances in thin-film solid-state batteries (TFSSBs) may capitalize on 3D structuring using high-aspect-ratio substrates such as nanoscale pits, pores, trenches, flexible polymers, and textiles. This will require conformal processes such as atomic layer deposition (ALD) for every active functional component of the battery. In this paper, we explore the deposition and electrochemical properties of SnO 2, SnN y, and SnO xN y thin films as TFSSB anode materials, grown by ALD using tetrakisdimethylamido(tin), H 2O, and N 2 plasma as precursors. By controlling the dose ratio between H 2O and N 2, the N–O fraction can be tuned betweenmore » 0% N and 95% N. The electrochemical properties of these materials were tested across a composition range varying from pure SnO 2, to SnON intermediates, and pure SnNy. In TFSSBs, the SnNy anodes are found to be more stable during cycling than the SnO 2 or SnO xN y films, with an initial reversible capacity beyond that of Li–Sn alloying, retaining 75% of their capacity over 200 cycles compared to only 50% for SnO 2. Lastly, the performance of the SnO xN y anodes indicates that SnN y anodes should not be negatively impacted by small levels of O contamination.« less

High rate and stable cycling of lithium metal anode

DOE PAGES

Qian, Jiangfeng; Henderson, Wesley A.; Xu, Wu; ...

2015-02-20

Lithium (Li) metal is an ideal anode material for rechargeable batteries. However, dendritic Li growth and limited Coulombic efficiency (CE) during repeated Li deposition/stripping processes have prevented the application of this anode in rechargeable Li metal batteries, especially for use at high current densities. Here, we report that the use of highly concentrated electrolytes composed of ether solvents and the lithium bis(fluorosulfonyl)imide (LiFSI) salt enables the high rate cycling of a Li metal anode at high CE (up to 99.1 %) without dendrite growth. With 4 M LiFSI in 1,2-dimethoxyethane (DME) as the electrolyte, a Li|Li cell can be cycledmore » at high rates (10 mA cm -2) for more than 6000 cycles with no increase in the cell impedance, and a Cu|Li cell can be cycled at 4 mA cm-2 for more than 1000 cycles with an average CE of 98.4%. These excellent high rate performances can be attributed to the increased solvent coordination and increased availability of Li+ concentration in the electrolyte. Lastly, further development of this electrolyte may lead to practical applications for Li metal anode in rechargeable batteries. The fundamental mechanisms behind the high rate ion exchange and stability of the electrolytes also shine light on the stability of other electrochemical systems.« less

Comparison of reduction products from graphite oxide and graphene oxide for anode applications in lithium-ion batteries and sodium-ion batteries.

PubMed

Sun, Yige; Tang, Jie; Zhang, Kun; Yuan, Jinshi; Li, Jing; Zhu, Da-Ming; Ozawa, Kiyoshi; Qin, Lu-Chang

2017-02-16

Hydrazine-reduced graphite oxide and graphene oxide were synthesized to compare their performances as anode materials in lithium-ion batteries and sodium-ion batteries. Reduced graphite oxide inherits the layer structure of graphite, with an average spacing between neighboring layers (d-spacing) of 0.374 nm; this exceeds the d-spacing of graphite (0.335 nm). The larger d-spacing provides wider channels for transporting lithium ions and sodium ions in the material. We showed that reduced graphite oxide as an anode in lithium-ion batteries can reach a specific capacity of 917 mA h g -1 , which is about three times of 372 mA h g -1 , the value expected for the LiC 6 structures on the electrode. This increase is consistent with the wider d-spacing, which enhances lithium intercalation and de-intercalation on the electrodes. The electrochemical performance of the lithium-ion batteries and sodium-ion batteries with reduced graphite oxide anodes show a noticeable improvement compared to those with reduced graphene oxide anodes. This improvement indicates that reduced graphite oxide, with larger interlayer spacing, has fewer defects and is thus more stable. In summary, we found that reduced graphite oxide may be a more favorable form of graphene for the fabrication of electrodes for lithium-ion and sodium-ion batteries and other energy storage devices.

Self-Supported CoP Nanorod Arrays Grafted on Stainless Steel as an Advanced Integrated Anode for Stable and Long-Life Lithium-Ion Batteries.

PubMed

Xu, Xijun; Liu, Jun; Hu, Renzong; Liu, Jiangwen; Ouyang, Liuzhang; Zhu, Min

2017-04-19

To alleviate the capacity degradation of anode materials for Li-ion batteries, caused by serious volume expansion and particle aggregation, intensive attention has been devoted to the rational design and fabrication of novel anode architectures. Herein, self-supported CoP nanorod arrays have been facilely synthesized using hydrothemally deposited Co(CO 3 ) 0.5 (OH)⋅0.11 H 2 O nanorod arrays as the precursor, through a gas-phase phosphidation method. As the anode for Li-ion batteries, such 3D interconnected CoP nanorod arrays show an initial discharge capacity of 1067 mAh g -1 and a high reversible charge capacity of 737 mAh g -1 at 0.4 Ag -1 . After 400 cycles, their specific capacity can reach 510 mAh g -1 ; even after 900 cycles, they can still deliver a specific capacity of 390 mAh g -1 . CoP//LiCoO 2 full-cells also exhibit a high reversible capacity of 400 mAh g -1 after 50 cycles. These unique 3D interconnected CoP nanorod arrays also show ultrastable cycling performance over 500 cycles when used as the anode in a Na-ion battery. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Scalable Production of the Silicon-Tin Yin-Yang Hybrid Structure with Graphene Coating for High Performance Lithium-Ion Battery Anodes.

PubMed

Jin, Yan; Tan, Yingling; Hu, Xiaozhen; Zhu, Bin; Zheng, Qinghui; Zhang, Zijiao; Zhu, Guoying; Yu, Qian; Jin, Zhong; Zhu, Jia

2017-05-10

Alloy anodes possessed of high theoretical capacity show great potential for next-generation advanced lithium-ion battery. Even though huge volume change during lithium insertion and extraction leads to severe problems, such as pulverization and an unstable solid-electrolyte interphase (SEI), various nanostructures including nanoparticles, nanowires, and porous networks can address related challenges to improve electrochemical performance. However, the complex and expensive fabrication process hinders the widespread application of nanostructured alloy anodes, which generate an urgent demand of low-cost and scalable processes to fabricate building blocks with fine controls of size, morphology, and porosity. Here, we demonstrate a scalable and low-cost process to produce a porous yin-yang hybrid composite anode with graphene coating through high energy ball-milling and selective chemical etching. With void space to buffer the expansion, the produced functional electrodes demonstrate stable cycling performance of 910 mAh g -1 over 600 cycles at a rate of 0.5C for Si-graphene "yin" particles and 750 mAh g -1 over 300 cycles at 0.2C for Sn-graphene "yang" particles. Therefore, we open up a new approach to fabricate alloy anode materials at low-cost, low-energy consumption, and large scale. This type of porous silicon or tin composite with graphene coating can also potentially play a significant role in thermoelectrics and optoelectronics applications.

Evaluation of selected thermal control coatings for long-life space structures

NASA Technical Reports Server (NTRS)

Teichman, Louis A.; Slemp, Wayne S.; Witte, William G., Jr.

1992-01-01

Graphite-reinforced resin matrix composites are being considered for spacecraft structural applications because of their light weight, high stiffness, and lower thermal expansion. Thin protective coatings with stable optical properties and the proper ratio of solar absorption (alpha sub s) to thermal emittance (epsilon) minimize orbital thermal extremes and protect these materials against space environment degradation. Sputtered coatings applied directly to graphite/epoxy composite surfaces and anodized coatings applied to thin aluminum foil were studied for use both as an atomic oxygen barrier and as thermal control coatings. Additional effort was made to develop nickel-based coatings which could be applied directly to composites. These coating systems were selected because their inherent tenacity made them potentially more reliable than commercial white paints for long-life space missions. Results indicate that anodized aluminum foil coatings are suitable for tubular and flat composite structures on large platforms in low Earth orbit. Anodized foil provides protection against some elements of the natural space environment (atomic oxygen, ultraviolet, and particulate radiation) and offers a broad range of tailored alpha sub s/epsilon. The foil is readily available and can be produced in large quantities, while the anodizing process is a routine commercial technique.

Nanocarbon-Coated Porous Anodic Alumina for Bionic Devices

PubMed Central

Aramesh, Morteza; Tong, Wei; Fox, Kate; Turnley, Ann; Seo, Dong Han; Prawer, Steven; Ostrikov, Kostya (Ken)

2015-01-01

A highly-stable and biocompatible nanoporous electrode is demonstrated herein. The electrode is based on a porous anodic alumina which is conformally coated with an ultra-thin layer of diamond-like carbon. The nanocarbon coating plays an essential role for the chemical stability and biocompatibility of the electrodes; thus, the coated electrodes are ideally suited for biomedical applications. The corrosion resistance of the proposed electrodes was tested under extreme chemical conditions, such as in boiling acidic/alkali environments. The nanostructured morphology and the surface chemistry of the electrodes were maintained after wet/dry chemical corrosion tests. The non-cytotoxicity of the electrodes was tested by standard toxicity tests using mouse fibroblasts and cortical neurons. Furthermore, the cell–electrode interaction of cortical neurons with nanocarbon coated nanoporous anodic alumina was studied in vitro. Cortical neurons were found to attach and spread to the nanocarbon coated electrodes without using additional biomolecules, whilst no cell attachment was observed on the surface of the bare anodic alumina. Neurite growth appeared to be sensitive to nanotopographical features of the electrodes. The proposed electrodes show a great promise for practical applications such as retinal prostheses and bionic implants in general. PMID:28793486

Tin anode for sodium-ion batteries using natural wood fiber as a mechanical buffer and electrolyte reservoir.

PubMed

Zhu, Hongli; Jia, Zheng; Chen, Yuchen; Weadock, Nicholas; Wan, Jiayu; Vaaland, Oeyvind; Han, Xiaogang; Li, Teng; Hu, Liangbing

2013-07-10

Sodium (Na)-ion batteries offer an attractive option for low cost grid scale storage due to the abundance of Na. Tin (Sn) is touted as a high capacity anode for Na-ion batteries with a high theoretical capacity of 847 mAh/g, but it has several limitations such as large volume expansion with cycling, slow kinetics, and unstable solid electrolyte interphase (SEI) formation. In this article, we demonstrate that an anode consisting of a Sn thin film deposited on a hierarchical wood fiber substrate simultaneously addresses all the challenges associated with Sn anodes. The soft nature of wood fibers effectively releases the mechanical stresses associated with the sodiation process, and the mesoporous structure functions as an electrolyte reservoir that allows for ion transport through the outer and inner surface of the fiber. These properties are confirmed experimentally and computationally. A stable cycling performance of 400 cycles with an initial capacity of 339 mAh/g is demonstrated; a significant improvement over other reported Sn nanostructures. The soft and mesoporous wood fiber substrate can be utilized as a new platform for low cost Na-ion batteries.

Sea water magnesium fuel cell power supply

NASA Astrophysics Data System (ADS)

Hahn, Robert; Mainert, Jan; Glaw, Fabian; Lang, K.-D.

2015-08-01

An environmentally friendly magnesium fuel cell system using seawater electrolyte and atmospheric oxygen was tested under practical considerations for use as maritime power supply. The hydrogen rate and therefore the power density of the system were increased by a factor of two by using hydrogen evolution cathodes with a gas separation membrane instead of submerged cathodes without gas separation. Commercial magnesium AZ31 rolled sheet anodes can be dissolved in seawater for hydrogen production, down to a thickness below 100 μm thickness, resulting in hydrogen generation efficiency of the anode of over 80%. A practical specific energy/energy density of the alloy of more than 1200 Wh/kg/3000 Wh/l was achieved when coupled to a fuel cell with atmospheric air breathing cathode. The performance of several AZ31 alloy anodes was tested as well as the influence of temperature, electrolyte concentration and anode - cathode separation. The excess hydrogen produced by the magnesium hydrogen evolving cell, due to the negative difference effect, is proportional to the cell current in case of the AZ31 alloys, which simplifies system control considerably. Stable long-term operation of the system was demonstrated at low pressures which can be maintained in an open-seawater-submerged hydrogen generator.