bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructural Characterization of Mn Oxide/PEDOT Electrodes with Rod-Like Structures for Application as Electrochemical Capacitors
Authors: Babakhani Banafsheh , Ivey Douglas G.
Published: April 2010

Mn oxide/PEDOT coaxial core/shell electrodes were electrochemically synthesized without any catalysts or templates using a stepwise synthetic approach. Mn oxide (1-1.5 µm diameter) rods were first synthesized by anodic deposition from a 0.01M Mn acetate solution, then coated electrochemically with a conducting polymer (PEDOT). The morphology of the electrodes depended on the pH of the electrolyte, deposition potential, current density and polymer deposition time, which affect the electrochemical behavior of the capacitor. The capacitive properties of the deposits were investigated in terms of morphological and structural evolution by characterization using scanning electron microscopy (SEM). The Mn oxide/PEDOT electrodes showed significantly improved specific capacity and charge/discharge stability relative to uncoated Mn oxide electrodes with rod-like structures. The best specific capacitance for Mn oxide/PEDOT coaxial rods produced sequentially was remarkably high (~285 Fg−1). Also, after 250 cycles in 0.5M Na2SO4 at 20 mVs−1, specific capacitance retention was 92% of the original value.
Peukert's Law of a Lead-Acid Battery Simulated by a Mathematical Model
Authors: Cugnet Mikäel G. , Dubarry Matthieu , Liaw Bor Yann
Published: April 2010

The Peukert's law is the most widely used empirical equation to represent the rate-dependent capacity of the lead-acid battery (LAB), mainly because it is easy to use, accurate, and applicable to a wide temperature range. In this work, we show that the Peukert behavior can be properly simulated by a mathematical model with only three rate-dependent parameters (specific active surface area, tortuosity exponent of the electrode morphology and the maximum capacity density). In this study, the analysis of the rate-dependent parameters of a flooded LAB provides an interesting case of study to understand the end of discharge (EOD) behavior of the battery at various rates, which constitutes the Peukert behavior of the LAB. Although at high rates, an exhaustion of sulfuric acid may occur in the positive plate as a result of acid transport limitation, the main factor that determines the EOD behavior is the change of the active surface area which is underpinned by the clogging of the pores due to sulfation of the electrodes, preventing the discharge reaction to occur at places where the active material might still be available.
A Comparison of Materials and Treatment of Materials for Vanadium Redox Flow Battery
Authors: Noack Jens , Tübke Jens
Published: April 2010

Because of their unique properties redox flow batteries are promising candidates to meet the increasing demand for energy storage solutions resulting from the increasing use of fluctuating renewable energy sources. Because of the relatively high cost of the energy converter, in particular the electrode materials and the ion conducting membrane, research to improve energy efficiency and power density has been carried out. To compensate NAFION®, the anion-conducting membrane FAP was investigated, which can achieve the same performance as NAFION® but is porous. The performance of graphite felts shows a clear dependence on the type of thermal hydrophilisation. Cells using natural graphite as an electrode material have a lower internal resistance and higher reactivity than those with graphite composite electrodes.
Novel Materials and Technologies of Microbial Fuel Cell in Environmental Engineering
Authors: Wang Li , Zhou Xiangtong , Zhong Su , Zhou Na
Published: April 2010

Electrodes, catalysts, membranes, if present, are three main components in constructing an MFC for harvesting desired maximum power density and achieving higher coulombic efficiency (CE). Great improvements have been made, based on previous researches, in developing and diversifying materials, aside from architectures. Electrodes most familiar to us are widely used carbon materials. For anodes, carbon matrix composites (e.g., a combination of polyaniline (PANI) with TiO2 using carbon as substrate) have gained special attention, though carbon material itself can exhibit excellent performance by diversifying molecular structures such as carbon nanotubes (CNTs). In the meanwhile, the evolution of MFC architectures, heading to the direction of improving power generation, contributes to the combination of membranes and cathodes from separate modes to diverse assemblies, on which all sorts of catalysts, such as from commonly used Pt to iron phthalocyanine (Pc), metal tetramethoxyphenylporphyrin (TMPP), MnOx, or pyrolyzed iron(ll) phthalocyanine (pyr-FePc), can immobilize through synthesis of these catalysts with polymer such as Nafion 117 (Dupont Co., USA) or tetrafluoroethylene (Teflon) containing functional groups or Polypyrrole (PPy). In addition, catholytes with aqueous cathode immersed or flowing through the surface of air-cathode are favorably proposed containing transition metal redox couples or iron chelates. This paper is mainly aimed at reviewing the development of materials in recent years and making several proposals.
Proton Conductivity Studies of Y-Doped Barium Zirconate: Theoretical and Experimental Approaches
Authors: Pornprasertsuk Rojana , Kosasang Onthida , Somroop Kittichai , Jinawath Supatra , Prinz Fritz B.
Published: April 2010

The proton conductivities of BaZr1-xYxO3-δ (BYZ) pellet samples with x = 0.06 to 0.4 were studied. The analysis showed that the optimum doping concentrations for bulk and grain boundary proton conductivity were at x = 0.1 and 0.2, respectively. The activation energies of the proton conductivity in bulk were between 0.42-0.47 eV, and 0.68-0.82 eV in the grain boundary. To gain more insight into the ionic conductivity mechanism in BYZ, quantum simulations complemented with kinetic Monte Carlo technique was employed to simulate proton and oxide ion migration processes in 8-30 at.% BYZ supercell. The results reveal the effect of defect associations on the proton and oxide ion migration and confirm the domination of proton conductivity on the overall ionic conductivity at all doping concentrations throughout the temperature range of this study. The optimum doping concentrations for the proton and oxide ion conductivities were extracted and compared with the experimental results.
Synthesis and Thermal Behavior of An Amorphous Solid Polymer Electrolyte
Authors: Barbosa Paula , Rodrigues Luísa C. , Silva M. Manuela , Smith Michael , Costa Marta
Published: April 2010

In this study the synthesis of an amorphous polymer network, poly[oxymethylene-oligo(oxyethylene)], designated as aPEO, is described. This polymer has been characterized by gel permeation chromatography, thermal analysis, conductivity measurements, evaluation of electrochemical stability and nuclear magnetic resonance spectroscopy. The synthetic procedure developed permits partial fractionation of the product of the polymerization reaction. This host appears to be a promising polymer for application in batteries and electrochromic devices since it provides access to amorphous linear macromolecules with good mechanical properties and promising electrochemical behavior.
Direct Oxidation of Ammonia Borane as an Alternative Fuel at Nanoporous Au
Authors: Nagle Lorraine C. , Rohan J. F.
Published: April 2010

Ammonia borane (AB) is a chemically stable, non-toxic solid with a high hydrogen content (19.5 wt. %) which is easily transported and is highly soluble in water. It has been shown that hydrogen can be released from AB via catalytic hydrolysis or thermal decomposition. It can thermally decompose in the temperature range 340-410 K to liberate 2.2 mol H2 per mol of ammonia borane which is equivalent to a hydrogen storage density of 14.3 wt. %. The high energy density coupled with the moderate decomposition temperature make ammonia borane an attractive hydrogen source for fuel cells. However, if the direct electrochemical oxidation of ammonia borane occurs in a fuel cell a more negative potential and greater power can be obtained than indirectly using hydrogen as the fuel. A novel direct AB fuel cell (DABFC) can be proposed by combining the anodic oxidation of AB given be Eqn. 1 and cathodic reduction of oxygen (Eqn. 2). NH3BH3 + 6OH- = BO2- + 4NH4++ 4H2O + 6e E0 = -1.216 V vs SHE (1) 1.5O2 + 3H2O + 6e = 6OH- E0 = 0.40V vs SHE (2) DABFC: NH3BH3 + 1.5O2 = BO2- + NH4+ + H2O E0 = 1.616 V (3)
Fabrication and Characterization of Noble Metal Nanowires for Nanogap Devices
Authors: Nambi Krishnan Jegatha , Lee Byung Chul , Shin Hyun Joon , Kim Sang Kyung K.
Published: April 2010

A new method called the selective metal nanoscale etch method (SMNEM) has been developed for fabricating Au nanowire arrays. The precise control in positioning of the Au nanowires on the substrates was achieved as the Au nanowires were formed through the edges of Ni films. The synthesis of Au nanowires of different sizes was made possible by critically controlling the deposition rate of Ni layer. The Au nanowire loops with 185 nm width and 100 nm height were observed. Also this process was evaluated by varying the physical parameters of the electroless plating method such as plating time and temperature. This method paves way for the easy and cost effective fabrication of noble-metal nanowire arrays/loops.
Competitive Methods for Fabrication of Nanochips and Replacement of Au, Ag and Pd with Nonprecious Metals
Authors: Khoperia Teimuraz N. , Mamniashvili Grigor , Khoperia Nikoloz , Zedginidze Tinatin I. , Chavchanidze David
Published: April 2010

Electroless metallization technology which allowed replacing adequately Au and Ag with Ni-P or Ni-B alloys and simplifying significantly the metallization process was developed (1-5). Other proposed patentable nanomethods for the first time allow one to produce nanochips and photomasks with nano-sized adjacent elements by single optical UV photolithography (4). The proposed nanomethods are much more advantageous and simpler than other expensive and complicated methods such as e-beam, X-ray lithography or fabrication of the nanoelements using light phase shift photomasks. The proposed methods of metallization are widely used in electronics, piezoengineering and instrument-making. As a result Au, Ag and Pd were replaced with the alloys of non-precious metals, usage of toxic substances was eliminated. Methods of fabricating the ultra-thin pore free electroless coatings on micro-, meso- and nano-sized particles are proposed.
Template Assisted Growth and Characterization of Electrodeposited Permalloy(Ni80Fe20)/Cu Multilayered Nanowires
Authors: Kok Kuan-Ying , Hangarter Carlos , Goldsmith Bryan , Ng Inn-Khuan , Saidin Nur Ubaidah , Myung Nosang V.
Published: April 2010

Permalloy (Ni80Fe20)/Cu multilayered nanowires (NWs) were potentiostatically electrodeposited within the nanopores of anodized alumina from sulfate baths via pulse technique. Microstructures and compositions of the nanowires were characterized using various microscopy and spectroscopy techniques. The effects of deposition potential and concentration of metal ions were optimized to reduce composition inhomogeneity and incorporation of copper in the permalloy layers. Composition of the NiFe layers was found to be close to 20% Fe with maximum 5% Cu. Our experimental observations show that individual nanowires exhibit distinct and coherent layering structure with rough and wavy interfaces. Synthesized single nanowires was also AC dielectrophoretically assembled across microfabricated gold electrodes for subsequent magnetoresistance measurement.
Influence of the Electrochemical Process Parameters on the Magnetic Behavior of a Silicon/Metal Nanocomposite
Authors: Rumpf Klemens , Granitzer Petra , Pölt Peter
Published: April 2010

A silicon/metal nanocomposite is fabricated electrochemically by anodization of a silicon wafer leading to a porous structure and subsequent metal deposition into the pores. The pores are oriented and separated from each other, offering a morphology in the mesoporous regime. The precipitation of the metal within the pores is performed by pulsed electrodeposition whereas the pulses are used as a tool to influence the structural characteristics of the embedded metal structures. By varying the frequency of the pulsed current the geometry of the metal structures can be modified between spherical particles and needle-like structures of a few microns in length. Magnetic characteristics of the nanocomposite samples depend on the shape of the incorporated structures but also on their magnetic interactions.
Electrodeposition of Nanocrystalline Metals on Open Cell Metal Foams: Improved Mechanical Properties
Authors: Jung Anne , Natter Harald , Hempelmann Rolf , Diebels Stefan , Koblischka Michael R. , Hartmann Uwe , Lach Erhardt
Published: April 2010

In order to enhance their stiffness, strength and energy absorption capability open-cell aluminum foams have been coated with nickel by electrodeposition. The coating thickness distribution is very important for the properties of the coated foams. A method to assess the coating thickness distribution by scanning the magnetic flux density distribution has been evaluated. The mechanical behavior has been investigated by quasi-static compression tests. The energy absorption capability increases linearly with the coating thickness, both for the absolute values and per foam thickness, but per density or mass the energy absorption capability reaches a saturation level. So there is an optimum in coating thickness. A decrease in pore size from 10 to 30 ppi more than doubles the energy absorption capability per foam thickness of coated foams.
Cathodic Deposition of ZnSe on Copper Substrates
Authors: Panagopoulos Christos , Tsoutsouva Maria , Chaidouti S. , Papadimitriou D.
Published: April 2010

In this work, ZnSe thin films were cathodically electrodeposited on copper (Cu) substrates from aqueous solutions of ZnSO4 and SeO2 using a three electrode configuration. Cyclic voltampèrometry has been applied to determine the deposition potential range. The deposited films were composed of polycrystalline cubic ZnSe (111) and elemental selenium. The highest zinc content was observed on films deposited at E=−0.6 V vs SCE. The Zn:Se atomic percentage obtained by EDAX approached 1:1 after annealing at 250oC for 30 min. The films were found to have 44 nm lowest surface roughness and 15% highest reflectance. The results of this study suggest that the electrodeposited ZnSe films are suitable for applications in photovoltaic technology.
Area Effects on the Mott-Schottky Behavior of Anodic Films Formed on AISI 304 Stainless Steel
Authors: Taveira Luciano V. , Dalla Corte Daniel A. , Dick Luis Frederico P.
Published: April 2010

The electronic properties of thick oxide films formed on AISI 304L by hot acid anodizing was investigated using the Mott-Schottky approach. All modified films showed n-type and p-type behavior, depending on the applied potential. The incorporation of molybdate and niobil oxalate during the anodization affected mainly the acceptor concentration. The apparent increase in the dopant concentrations is mainly explained by surface area increase associated to the treatments.
Re-Oxidation Behavior of Cr and V Ions in the Boiling Nitric Acid Solution and Acceleration Effect on Corrosion Rate of Stainless Steel
Authors: Yamamoto Masahiro , Motooka Takafumi , Ueno Fumiyoshi , Kato Chiaki
Published: April 2010

In order to clarify the acceleration effect of corrosion with small amount of oxidizing ion addition in boiling nitric acid solution, Cr(VI) and V(V) ions added solution were examined Cr(VI) and/or V(V) added nitric acid solutions accelerated corrosion rates of SUS304ULC. The acceleration effect of Cr was larger than that of V. Although the acceleration effect of Cr rapidly decreased, that of V stayed constant. Concentration of Cr(VI) in the solution was decreased correspond to the corrosion rate. Re-oxidation of V is faster than that of Cr. Cr(VI) ions are reduced to Cr(III) by corrosion reaction of SUS340ULC but a little amount of them are re-oxidized. On the other hand, V(V) ions are also reduced to V(IV) and almost of all of them are re-oxidized to V(V). So, corrosion rate of V added solution stayed constant and that of Cr added decreased.
A Comparative Study of the Mott-Schottky Behavior of Oxide Films on Stainless Steels in Ionic Liquids and in Aqueous Solutions
Authors: Maria Ane C. , Benedetti Tânia M. , Torresi Roberto , Dick Luis Frederico P.
Published: April 2010

The semiconducting properties of passive films formed on AISI304 steel, thermally at 400ºC or anodically in a borate buffer solution, were comparatively studied by capacitance measurements and the usual Mott-Shottky (MS) approach in an aqueous borate buffer solution of pH 9.2 and in BMMITFSI, a room temperature ionic liquid. This ionic liquid was used due to its wide electrochemical window of circa 4.3 V, enabling the verification of the accuracy of the MS approach. Two regions corresponding to p and n-type semiconduction were observed in both electrolytes, but calculated dopant concentrations were not always equal. In the ionic liquid a second deeper donor level was always present, which must be further investigated.
Effect of Solution Properties on the AC/DC Spark Anodizing of Al-Cu alloy AA2219
Authors: Alsrayheen Enam A. , McLeod Eric J. , Rateick Richard G. , Birss Viola I.
Published: April 2010

An AC/DC spark anodizing method was used to coat the aluminum-copper (Al-Cu) alloy AA2219 with oxide films to protect them form corrosion. The effect of electrolyte solution composition and the lifetime use of the anodizing solution on the anodizing process and the oxide film properties have been investigated. In this work, an anodizing solution containing 0.15 M KOH and various concentrations of Na2SiO3 has been used. Oxide film characterizations were carried out using scanning electron microscopy (SEM) and energy dispersive x-ray (EDX). Corrosion assessment was carried out using linear sweep voltammetgram (LSV) in borate buffer solution (pH 7).
Preferential Grain Etching of AlMgSi(Zn) Model Alloys
Authors: Holme Bo̸rge , Ljones Nina , Bakken Astrid , Lunder Otto , Lein John Erik , Vines Lasse , Hauge Tom , Bauger Øystein , Nisancioglu Kemal
Published: April 2010

Preferential grain etching is a problem occurring on aluminium products during alkaline etching prior to anodizing, especially if the etching bath contains small amounts of dissolved Zn. The visually uneven, "grainy" surface is caused by different etch rates for different grains, giving a terrace-like surface topography. Polished samples of an AlMgSi alloy with different amounts of Zn were etched in NaOH solution. Grain orientations in selected areas were determined by Electron BackScatter Diffraction (EBSD). The low-Zn samples did not show preferential grain etching. On the higher-Zn alloys, grains with surface planes close to {111} were found to etch at a higher rate than the other orientations. Secondary Ion Mass Spectrometry (SIMS) depth profiling and imaging, combined with White Light Interferometry (WLI) analysis, showed a clear correlation between the deep lying grains and a surface enriched in Zn, suggesting that Zn enrichment by alkaline etching occurred by selective dissolution of aluminium.
Role of Hydrogen Peroxide in Tin Dioxide Preparation
Authors: Macalik Michal , Sedlarikova Marie , Vondrak Jiri , Mohelnikova Jitka
Published: April 2010

Thin layers of tin dioxide were prepared by spraying of solution containing tin dichloride and hydrogen peroxide on glass substrates heated to 400 - 450 oC. The action of peroxide is explained as formation of peroxostannic compounds. The layers are crystallic, reasonably transparent and exhibit conductivity of N type as detected by voltammetric measurements of system ferrocene - ferrocenium in propylene carbonate.
The islet-acinar axis of the pancreas: more than just insulin
Authors: Barreto Savio G. , Carati Colin J. , Toouli James , Saccone Gino T. P.
Published: April 2010

Although the role of the islets in the regulation of acinar cell function seemed a mystery to investigators who observed their dispersion among pancreatic acini, over time an appreciation for this intricate and unique structural arrangement has developed. The last three decades have witnessed a steadily growing understanding of the interrelationship of the endocrine and the exocrine pancreas. The islet innervation and vascular anatomy have been more fully characterized and provide an appropriate background for our current understanding. The interrelationship between the endocrine and exocrine pancreas is mediated by islet-derived hormones such as insulin and somatostatin, other humoral factors including pancreastatin and ghrelin, and also neurotransmitters (nitric oxide, peptide YY, substance P, and galanin) released by the nerves innervating the pancreas. Although considerable progress has been achieved, further work is required to fully delineate the complex interplay of the numerous mechanisms involved. This review aims to provide a comprehensive update of the current literature available, bringing together data gleaned from studies addressing the actions of individual hormones, humoral factors, and neurotransmitters on the regulation of amylase secretion from the acinar cell. This comprehensive view of the islet-acinar axis of the pancreas while acknowledging the dominant role played by insulin and somatostatin on exocrine secretion sheds light on the influence of the various neuropeptides on amylase secretion.
Aryl hydrocarbon receptor and NF-E2-related factor 2 are key regulators of human MRP4 expression
Authors: Xu Shuhua , Weerachayaphorn Jittima , Cai Shi-Ying , Soroka Carol J. , Boyer James L.
Published: April 2010

Multidrug resistance protein 4 (MRP4; ABCC4) is an ATP binding cassette transporter that facilitates the excretion of bile salt conjugates and other conjugated steroids in hepatocytes and renal proximal tubule epithelium. MRP4/Mrp4 undergoes adaptive upregulation in response to oxidative and cholestatic liver injury in human and animal models of cholestasis. However, the molecular mechanism of this regulation remains to be determined. The aryl hydrocarbon receptor (AhR) and NF-E2-related factor 2 (Nrf2) play important roles in protecting cells from oxidative stress. Here we examine the role of these two nuclear factors in the regulation of the expression of human MRP4. HepG2 cells and human hepatocytes were treated with the AhR and Nrf2 activators, 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD), 3-methylcholanthrene (3-MC), or oltipraz and other nuclear receptor agonists. TCDD, 3-MC, and oltipraz significantly increased MRP4 expression at mRNA and protein levels. Computer program analysis revealed three Xenobiotic response element (XRE) and one Maf response element sites within the first 500 bp of the MRP4 proximal promoter. Luciferase reporter assay detected strong promoter activity (53-fold higher than vector control) in this region. TCDD and 3-MC also induced promoter activity in the reporter assays. Mutation of any of these XRE sites significantly decreased MRP4 promoter activity in reporter assays, although XRE2 demonstrated the strongest effects on both basal and TCDD-inducible activity. EMSA and chromatin immunoprecipitation assays further confirmed that both AhR and Nrf2 bind to the proximal promoter of MRP4. Our findings indicate that AhR and Nrf2 play important roles in regulating MRP4 expression and suggest that agents that activate their activity may be of therapeutic benefit for cholestasis.
Late Common Iliac Artery Stent Thrombosis in a Patient with Terminal Malignancy
Authors: Can Mehmet M. , Tanboğa İbrahim H. , Özveren Olcay , Karabay Can Yucel , Akgün Taylan , Türkyılmaz Erdem , Tokgöz Hacer C. , Kaymaz Cihangir , Serebruany Victor
Published: April 2010

Narrowing of the iliac artery is a common presentation of systemic atherosclerosis. With the recent development of invasive techniques, angioplasty and stenting offer excellent results for fixing limb ischemia of aorto-iliac arteries. However, despite novel interventional approaches and constantly increasing experience, complications such as distal embolization, stent migration, acute or subacute iliac artery occlusion, dissection, and perforations are still challenging. Early restenosis and/or reocclusion of peripheral artery stents is uncommon, but the risk of delayed or late thrombotic occlusions of iliac artery stents is unclear. Although with questionable impact, hypercoagulable state or patient noncompliance may contribute to the pathogenesis of stent thrombosis. We describe a patient with terminal renal cell carcinoma who developed late iliac artery stent thrombosis despite dual chronic antiplatelet therapy with aspirin and clopidogrel.
Safety Profile of MLC601 (Neuroaid®) in Acute Ischemic Stroke Patients: A Singaporean Substudy of the Chinese Medicine Neuroaid Efficacy on Stroke Recovery Study
Authors: Young Sherry H.Y. , Zhao Yudong , Koh Angeline , Singh Rajinder , Chan Bernard P.L. , Chang Hui Meng , Venketasubramanian N. , Chen Christopher
Published: April 2010

Background: Previous clinical trials have shown that Neuroaid® (MLC601), a traditional Chinese medicine, shows good tolerability and superiority over another traditional Chinese medicine in terms of neurological disability and functional outcome and thus may be beneficial as part of a poststroke rehabilitation program. The safety of MLC601 on hemostasis, hematology and biochemistry has been established in normal subjects and patients with nonacute stroke over a short treatment period. We assessed the safety of Neuroaid in patients with acute stroke treated for 3 months in a substudy of an ongoing randomized placebo-controlled trial. Methods: Laboratory tests (biochemical, hematological and electrocardiogram) were conducted at the month 3 follow-up, in addition to baseline tests. A total of 114 patients were recruited. As there were 13 dropouts, a total of 52 patients on MLC601 and 49 on placebo were available for analysis. Serious adverse events (SAEs) were also analyzed. Results: There were no statistically or clinically significant differences between treatment groups in biochemical, hematological or electrocardiogram tests at month 3, nor any statistically or clinically significant differences in the absolute and relative changes of the various parameters between baseline and 3 months. SAEs were similar and were those commonly seen in stroke patients. Conclusions: Longer-term laboratory safety data show no differences between MLC601 and placebo, confirming the safety of MLC601 in acute stroke patients receiving a 3-month treatment.
Association of the 9p21.3 Locus With Risk of First-Ever Myocardial Infarction in Pakistanis
Authors: Saleheen Danish , Alexander Myriam , Rasheed Asif , Wormser David , Soranzo Nicole , Hammond Naomi , Butterworth Adam , Zaidi Moazzam , Haycock Philip , Bumpstead Suzannah , Potter Simon , Blackburn Hannah , Gray Emma , Di Angelantonio Emanuele , Kaptoge Stephen , Shah Nabi , Samuel Maria , Janjua Ahmedyar , Sheikh Nasir , Haider Shajjia Razi , Murtaza Muhammed , Ahmad Usman , Hakeem Abdul , Memon Muhammad Ali , Mallick Nadeem Hayat , Azhar Muhammad , Samad Abdus , Rasheed Syed Zahed , Gardezi Ali Raza , Memon Nazir Ahmed , Ghaffar Abdul , Memon Fazal-ur-Rehman , Zaman Khan Shah , Kundi Assadullah , Yaqoob Zia , Cheema Liaquat Ali , Qamar Nadeem , Faruqui Azhar , Jooma Rashid , Niazi Jawaid Hassan , Hussain Mustafa , Kumar Kishore , Saleem Asim , Kumar Kishwar , Daood Muhammad Salman , Memon Fatima , Gul Aftab Alam , Abbas Shahid , Zafar Junaid , Shahid Faisal , Memon Zehra , Bhatti Shahzad Majeed , Kayani Waleed , Ali Syed Saadat , Fahim Muhammad , Ishaq Muhammad , Frossard Philippe , Deloukas Panos , Danesh John
Published: April 2010

Objective—

To examine variants at the 9p21 locus in a case-control study of acute myocardial infarction (MI) in Pakistanis and to perform an updated meta-analysis of published studies in people of European ancestry.

Methods and Results—

A total of 1851 patients with first-ever confirmed MI and 1903 controls were genotyped for 89 tagging single-nucleotide polymorphisms at locus 9p21, including the lead variant (
rs1333049
) identified by the Wellcome Trust Case Control Consortium. Minor allele frequencies and extent of linkage disequilibrium observed in Pakistanis were broadly similar to those seen in Europeans. In the Pakistani study, 6 variants were associated with MI (
P
<10
−2
) in the initial sample set, and in an additional 741 cases and 674 controls in whom further genotyping was performed for these variants. For Pakistanis, the odds ratio for MI was 1.13 (95% CI, 1.05 to 1.22;
P
=2×10
−3
) for each copy of the C allele at
rs1333049
. In comparison, a meta-analysis of studies in Europeans yielded an odds ratio of 1.31 (95% CI, 1.26 to 1.37) for the same variant (
P
=1×10
−3
for heterogeneity). Meta-analyses of 23 variants, in up to 38 250 cases and 84 820 controls generally yielded higher values in Europeans than in Pakistanis.

Conclusion—

To our knowledge, this study provides the first demonstration that variants at the 9p21 locus are significantly associated with MI risk in Pakistanis. However, association signals at this locus were weaker in Pakistanis than those in European studies.
Calmodulin Interacts With ATP Binding Cassette Transporter A1 to Protect From Calpain-Mediated Degradation and Upregulates High-Density Lipoprotein Generation
Authors: Iwamoto Noriyuki , Lu Rui , Tanaka Nobukiyo , Abe-Dohmae Sumiko , Yokoyama Shinji
Published: April 2010

Objective—

To investigate the interaction of ATP-binding cassette transporter A1 (ABCA1) with calmodulin in relation to its calpain-mediated degradation because many calpain substrates bind calmodulin to regulate cellular functions.

Methods and Results—

The activity of ABCA1 is regulated through proteolysis by calpain. An immunoprecipitation and glutathione S-transferase pull-down assay revealed that ABCA1 directly binds calmodulin in a Ca
2+
-dependent manner. The cytoplasmic loop of ABCA1 contains a typical calmodulin binding sequence of 1-5-8-14 motifs (1245 to 1257 amino acids). The peptide of this region showed binding to calmodulin, and deletion of the 1-5-8-14 motif abolished this interaction. This motif is located near the ABCA1 Pro-Glu-Ser-Thr sequence, and the presence of calmodulin/Ca
2+
protected the peptides from proteolysis by calpain. The knockdown of calmodulin by a specific small and interfering RNA increased the degradation of ABCA1 and decreased ABCA1 protein and apolipoprotein A-I–mediated lipid release. Surprisingly, calmodulin inhibitor W7 increased calmodulin binding to ABCA1 and protected it from calpain-mediated degradation, consistent with our previous finding that this compound increased apolipoprotein A-I–mediated cell cholesterol release.

Conclusion—

Calmodulin directly binds and stabilizes ABCA1 in the presence of Ca
2+
and increases the generation of high-density lipoprotein.
A Systematic Review of Dynamic Cerebral and Peripheral Endothelial Function in Lacunar Stroke Versus Controls
Authors: Stevenson Susan F. , Doubal Fergus N. , Shuler Kirsten , Wardlaw Joanna M.
Published: April 2010

Background and Purpose—

The etiology of cerebral small vessel disease is unknown. An association with endothelial dysfunction has been suggested. We systematically assessed all relevant studies of dynamic endothelial function in patients with lacunar stroke as a marker of small vessel disease.

Methods—

We searched for studies of cerebral or peripheral vascular reactivity in patients with lacunar or cortical (ie, large artery atheromatous) ischemic stroke or nonstroke control subjects. We calculated standardized mean difference (SMD) in vascular reactivity±95% CIs between small vessel disease and control groups.

Results—

Sixteen publications (974 patients) were included. In lacunar stroke, cerebrovascular reactivity (n=534) was reduced compared with age-matched normal (SMD −0.94, 95% CI −1.17 to −0.70), but not age+risk factor-matched control subjects (SMD 0.08, 95% CI −0.36 to 0.53) or cortical strokes (SMD −0.29, 95% CI −0.69 to 0.11); forearm flow-mediated dilatation (n=401) was reduced compared with age-matched normal control subjects (SMD −1.04, 95% CI −1.33 to −0.75) and age+risk factor-matched control subjects (SMD −0.94, 95% CI −1.26 to −0.61), but not cortical strokes (SMD −0.23, 95% CI −0.55 to 0.08).

Conclusions—

Endothelial dysfunction is present in patients with lacunar stroke but may simply reflect exposure to vascular risk factors and having a stroke, because a similar degree of dysfunction is found in cortical (large artery atheromatous) stroke. Current data do not confirm that endothelial dysfunction is specific to small vessel stroke. Future studies should include control subjects with nonlacunar stroke.
Randomized, Placebo-Controlled, Clinical Trial of Donepezil in Vascular Dementia
Authors: Román Gustavo C. , Salloway Stephen , Black Sandra E. , Royall Donald R. , DeCarli Charles , Weiner Michael W. , Moline Margaret , Kumar Dinesh , Schindler Rachel , Posner Holly
Published: April 2010

Background and Purpose—

We sought to assess the efficacy and safety of donepezil in patients with vascular dementia (VaD) fulfilling National Institute of Neurological Disorders and Stroke–Association Internationale pour la Recherche et l’Enseignement en Neurosciences criteria.

Methods—

This international, multicenter, 24-week trial was conducted from March 2003 to August 2005. Patients (N=974; mean age, 73.0 years) with probable or possible VaD were randomized 2:1 to receive donepezil 5 mg/d or placebo. Coprimary outcome measures were scores on the Vascular-Alzheimer Disease Assessment Scale–Cognitive Subscale and Clinician’s Interview–Based Impression of Change, plus carer interview. Analyses were performed for the intent-to-treat population with the last-observation-carried-forward method.

Results—

Compared with placebo, donepezil-treated patients showed significant improvement from baseline to end point on the Vascular-Alzheimer Disease Assessment Scale–Cognitive Subscale (least-squares mean difference, −1.156; 95% CI, −1.98 to −0.33;
P
<0.01) but not on the Clinician’s Interview–Based Impression of Change, plus carer interview. Patients with hippocampal atrophy who were treated with donepezil demonstrated stable cognition versus a decline in the placebo-treated group; in those without atrophy, cognition improved with donepezil versus relative stability with placebo. Results on secondary efficacy measures were inconsistent. The incidence of adverse events was similar across groups. Eleven deaths occurred in the donepezil group (1.7%), similar to rates previously reported for donepezil trials in VaD, whereas no deaths occurred in the placebo group.

Conclusions—

Patients treated with donepezil 5 mg/d demonstrated significant improvement in cognitive, but not global, function. Donepezil was relatively well tolerated; adverse events were consistent with current labeling. Mortality in the placebo group was unexpectedly low. The differential treatment response of VaD patients by hippocampal size suggests that hippocampal imaging warrants further investigation for understanding VaD.
Population-Based Study of Behavior Immediately After Transient Ischemic Attack and Minor Stroke in 1000 Consecutive Patients
Authors: Chandratheva Arvind , Lasserson Daniel S. , Geraghty Olivia C. , Rothwell Peter M.
Published: April 2010

Background and Purpose—

Most guidelines now recommend that patients with minor stroke or high-risk transient ischemic attack (TIA) are assessed within 24 hours of their event, but the feasibility of this depends on patients’ behavior. We studied behavior immediately after TIA and minor stroke according to clinical characteristics, patients’ perception of the nature of the event, and their predicted stroke risk.

Methods—

In a population-based study in Oxfordshire, UK, with face-to-face interview of 1000 consecutive patients with TIA and minor stroke (National Institutes of Health Stroke Scale ≤5) from 2002 to 2007 (Oxford Vascular Study), we studied delay in seeking medical attention and identified patients who did not seek attention after an initial event and only presented after a recurrent stroke.

Results—

Of 1000 patients (459 TIAs, 541 minor strokes), 300 (67%) with TIA and 400 (74%) with minor stroke sought medical attention within 24 hours and 208 (47%) and 234 (46%), respectively, sought attention within 3 hours. Most patients (77%) first sought attention through their primary care physician. In patients with TIA, incorrect recognition of symptoms, absence of motor or speech symptoms, shorter duration of event, lower ABCD
2
score, no history of stroke or atrial fibrillation, and weekend presentation were associated with significantly longer delays. However, age, sex, social class, and educational level were all unrelated to either correct recognition of symptoms or to delay in seeking attention. Of 129 patients with TIA or minor stroke who had a recurrent stroke within 90 days, 41 (31%) did not seek medical attention after their initial event. These patients were more likely to have had a TIA (
P
=0.003), shorter duration of event (
P
=0.02), and a history of TIA (
P
=0.09) and less likely to have had motor (
P
=0.004) or speech symptoms (
P
=0.04) compared with those patients who sought medical attention for their initial event.

Conclusion—

Approximately 70% of patients do not correctly recognize their TIA or minor stroke, 30% delay seeking medical attention for >24 hours, regardless of age, sex, social class, or educational level, and approximately 30% of early recurrent strokes occur before seeking attention. Without more effective public education of all demographic groups, the full potential of acute prevention will not be realized.
Using Transcranial Direct-Current Stimulation to Treat Stroke Patients With Aphasia
Authors: Baker Julie M. , Rorden Chris , Fridriksson Julius
Published: April 2010

Background and Purpose—

Recent research suggests that increased left hemisphere cortical activity, primarily of the left frontal cortex, is associated with improved naming performance in stroke patients with aphasia. Our aim was to determine whether anodal transcranial direct-current stimulation (tDCS), a method thought to increase cortical excitability, would improve naming accuracy in stroke patients with aphasia when applied to the scalp overlying the left frontal cortex.

Methods—

Ten patients with chronic stroke-induced aphasia received 5 days of anodal tDCS (1 mA for 20 minutes) and 5 days of sham tDCS (for 20 minutes, order randomized) while performing a computerized anomia treatment. tDCS positioning was guided by a priori functional magnetic resonance imaging results for each individual during an overt naming task to ensure that the active electrode was placed over structurally intact cortex.

Results—

Results revealed significantly improved naming accuracy of treated items (F[1,9]=5.72,
P
<0.040) after anodal tDCS compared with sham tDCS. Patients who demonstrated the most improvement were those with perilesional areas closest to the stimulation site. Crucially, this treatment effect persisted at least 1 week after treatment.

Conclusions—

Our findings suggest that anodal tDCS over the left frontal cortex can lead to enhanced naming accuracy in stroke patients with aphasia and, if proved to be effective in larger studies, may provide a supplementary treatment approach for anomia.
Dissemination of Thrombolysis for Acute Ischemic Stroke Across a Nation
Authors: Eriksson Marie , Jonsson Fredrik , Appelros Peter , Åsberg Kerstin Hulter , Norrving Bo , Stegmayr Birgitta , Terént Andreas , Asplund Kjell
Published: April 2010

Background and Purpose—

We used Riks-Stroke, the Swedish Stroke Register, to explore how thrombolysis has been disseminated in Swedish hospitals since it was approved in 2003.

Methods—

All 78 hospitals in Sweden admitting patients with acute stroke participate in Riks-Stroke. Between 2003 and 2008, 72 033 adult patients were hospitalized for acute ischemic stroke. We analyzed thrombolysis use by region, patient characteristics, and stroke service settings.

Results—

Nationwide, the use of thrombolysis increased from 0.9% in 2003 to 6.6% in 2008. There were marked regional differences in the dissemination of thrombolysis, but these gaps narrowed over time. Nonuniversity hospitals reached treatment levels similar to university settings, although with a 2- to 3-year delay. Symptomatic intracranial hemorrhage remained at the 3% to 9% level without an apparent time trend during dissemination. Independent predictors of higher thrombolysis use included younger age, male sex, not living alone, and no history of stroke or diabetes. In 2008, patients admitted to a stroke unit were 5 times more likely to receive thrombolysis than those admitted to general wards.

Conclusions—

Nationwide implementation of thrombolysis has been slow but has accelerated mainly due to increased access outside university hospitals. The increased use has been achieved safely, but access has been unequal.
Effectiveness of Primary and Comprehensive Stroke Centers
Authors: Meretoja Atte , Roine Risto O. , Kaste Markku , Linna Miika , Roine Susanna , Juntunen Merja , Erilä Terttu , Hillbom Matti , Marttila Reijo , Rissanen Aimo , Sivenius Juhani , Häkkinen Unto
Published: April 2010

Background and Purpose—

Previous studies show better outcomes for patients with stroke receiving care in stroke units, but many different stroke unit criteria have been published. In this study, we explored whether stroke centers fulfilling standardized Brain Attack Coalition criteria produce better patient outcomes than hospitals without stroke centers.

Methods—

We did an observational register–linkage study of all patients with ischemic stroke treated in Finland between 1999 and 2006. After exclusion of recurrent strokes and nonanalyzable patients, we included 61 685 consecutive patients treated in 333 hospitals classified in national audits either as Comprehensive Stroke Centers, Primary Stroke Centers, or General Hospitals according to Brain Attack Coalition criteria. Primary outcome measures were case-fatality and being in institutional care 1 year after stroke.

Results—

Care in stroke centers was associated with lower 1-year case-fatality and reduced institutional care compared with General Hospitals. The number-needed-to-treat to prevent 1 death or institutional care at 1 year was 29 for Comprehensive Stroke Centers and 40 for Primary Stroke Centers versus General Hospitals. Patients treated in stroke centers had lower mortality during the entire follow-up of up to 9 years and their median survival was increased by 1 year.

Conclusions—

This study shows a clear association between the level of acute stroke care and patient outcome and supports use of published criteria for primary and comprehensive stroke centers.
Dietary Folate and Vitamin B
6
and B
12
Intake in Relation to Mortality From Cardiovascular Diseases
Authors: Cui Renzhe , Iso Hiroyasu , Date Chigusa , Kikuchi Shogo , Tamakoshi Akiko
Published: April 2010

Background and Purpose—

The association of dietary folate and B vitamin intakes with risk of cardiovascular disease is controversial, and the evidence in Asian populations is limited.

Methods—

A total of 23 119 men and 35 611 women, age 40 to 79 years, completed a food frequency questionnaire in the Japan Collaborative Cohort Study. During the median 14-year follow-up, there were 986 deaths from stroke, 424 from coronary heart disease, and 2087 from cardiovascular disease.

Results—

Dietary folate and vitamin B
6
intakes were inversely associated with mortality from heart failure for men and with mortality from stroke, coronary heart disease, and total cardiovascular disease for women. These inverse associations did not change materially after adjustment for cardiovascular risk factors. No association was found between vitamin B
12
intake and mortality risk.

Conclusions—

High dietary intakes of folate and vitamin B
6
were associated with reduced risk of mortality from stroke, coronary heart disease, and heart failure among Japanese.
Prevalence of Compositional Features in Subclinical Carotid Atherosclerosis Determined by High-Resolution Magnetic Resonance Imaging in Chinese Patients With Coronary Artery Disease
Authors: Zhao Xihai , Zhao Qian , Chu Baocheng , Yang Yin , Li Feiyu , Zhou Xiao-Hua , Cai Jianming , Cai Zulong , Yuan Chun
Published: April 2010

Background and Purpose—

Previous studies have reported that carotid atherosclerosis frequently can be seen in coronary artery disease (CAD) patients. This study sought to determine the prevalence of compositional features in subclinical carotid atherosclerosis by MRI in CAD patients.

Methods—

Ninety-six subjects with suspected CAD but free of neurological symptoms underwent coronary CT angiography and carotid MRI including 3-dimensional time-of-flight, T1-weighted, T2-weighted, and proton density-weighted sequences at 3 T within a 2-week interval. The coronary artery calcium score (CACS) and degree of stenosis were measured. Areas for carotid lumen, wall, total vessel, and percent wall volume (wall volume/total vessel volume) were measured. The prevalence of carotid calcification, lipid-rich necrotic core, intraplaque hemorrhage, and surface disruption in coronary stenosis and CACS categories were determined.

Results—

Carotid percent wall volume was correlated with CACS (
P
=0.001). Both coronary stenosis and CACS were significantly associated with presence of carotid calcification (OR=5.79 for 1%–49% vs 0% stenosis; OR=10.23 for >50% vs 0% stenosis; OR=10.65 for CACS 1–399 vs CACS 0; and OR=20.28 for CACS >400 vs CACS 0; all
P
<0.05) and lipid-rich necrotic core (OR=10.29 for 1%–49% vs 0% stenosis; OR=4.66 for >50% vs 0% stenosis; OR=8.23 for CACS 1–399 vs CACS 0; and OR=11.87 for CACS >400 vs CACS 0; all
P
<0.05) High prevalence of lipid-rich necrotic core was found in low-grade coronary stenosis (75.6% in 1%–49% stenosis) and CACS (73.5% in CACS 1–399).

Conclusions—

Carotid plaque burden and compositional features are significantly associated with CAD severity. The finding of high prevalence of lipid-rich necrotic core in patients with low-grade coronary stenosis and CACS suggests the need for early monitoring of carotid atherosclerosis in CAD patients.
The Computer-Aided Design and Manufacture of Specific Objects
Authors: Shaw Michael
Published: April 2010

The author discusses his attempts to exploit computer-aided design and manufacture to extend Donald Judd's sculptural concept of Specific Objects. The paper focuses on the challenges of creating singular forms exhibiting both unity and variation through rapid prototyping. Consideration is also given to the broader consequences of sculpting through virtual CAD software, including outcomes such as kinetic inflatable sculptures and animated sculptures and drawings.
The Spectacle of Seismicity: Making Art from Earthquakes
Authors: Mudie Ella
Published: April 2010

Representations of earthquakes in visual art have the potential to function as spectacles (defined as striking or dramatic public displays); this in turn provokes consideration of how viewers construct meaning from such representations. The author examines the work of a number of artists arguably concerned with going beyond spectacular representations in their portrayals of earthquake activity. Particular focus is placed upon performative techniques meant not only to engage audiences with the properties of seismic phenomena but also to stimulate reflection on the complex psychological responses they may trigger, as well as their analogous relationships to conditions of environmental and cultural crisis.