bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Low Cell Voltages on the Performance of MCMB Anode and LiNi0.8Co0.2O2 Cathode
Authors: Bugga Ratnakumar V. , Smart Marshall C. , Krause Frederick C. , Hwang Constanza , Degrosse Patrick , Santee Stu , Puglia Frank J.
Published: July 2013

Lithium-ion cells employing graphitic anodes (graphite or MCMB) and lithiated metal oxide cathodes, Li(Ni,Co,Al)O2 are generally intolerant to low cell voltages, which is often attributed to the side reactions on the anode. Even though dissolution of the copper substrate at the anode is not thermodynamically favored at the anode potentials positive to lithium, mild copper dissolution was often reported to occur at positive potentials. Furthermore, the cell performance appears to degrade upon exposure to low voltages, even without any visible copper dissolution. One of the engineering batteries for the NASA Mars Science Laboratory (MSL) mission sustained a high impedance short due to a failure in the harness insulation, which resulted in the deep-discharge of multiple cells to low voltages, and an overall performance loss in these cells. Results from the laboratory test cells confirm the trend in the performance degradation as a function of low voltage exposure and point to, surprisingly, a degradation of the cathode, more than the anode. Electrochemical measurements, both ac impedance (EIS) and DC polarization show an unexpected trend that the cathode kinetics are affected by the deep-discharges to low voltages.
Cycling Fatigue Induced on Electrochemical Energy Storage Cells as a Result of High C Pulsed Charging
Authors: Novak Peter Michael , Wetz David Alan , Shrestha Biju
Published: July 2013

A 3Ah lithium-ion battery, LiNixCoyAl1-x-yO2, has been repeatedlyrecharged at an elevated C rate in a pulsed fashion to understand theimpact this has on cell lifetime. A peak charge rate of 33C, ~100 A, isapplied in 3 s increments with 6 s of idle time between pulses. Betweenrecharges, the cell is discharged at a constant current (CC) 1C rate. Cellfatigue is determined using electrochemical impedance spectroscopy (EIS)and capacity measurements. During each elevated recharge, the cellsvoltage, current, and temperature are monitored using high speed dataacquisition systems. EIS measurements are made before and after each1C-CC discharge. A second cell of the same type is also cycled on apotentiostat using a 1C-CC, constant voltage (CV) recharge and 1C-CCdischarge. The goal is to compare the aging of the two cells in order tounderstand the differences introduced from elevated recharge rates.
The Impact of High Pulsed Loading on the Fatigue of Electrochemical Energy Storage Devices
Authors: Shrestha Biju , Wetz David Alan , Novak Peter Michael
Published: July 2013

UT Arlington is researching the impact high pulsed loading has on high power electrochemical energy storage devices. Fundamental effects on aging due to high pulsed loading are being investigated by studying the capacity fade and changes in the cells electrochemical impedance [1]. Experiments have been performed in which a 3Ah LiNixCoyAl1-x-yO2 cell is discharged at rates as high as 83C (250 A) in a 10 kHz pulsed fashion for 140s. A 1C recharge procedure is used between discharge cycles. The experimental results obtained when cycling at elevated rates are compared to results obtained from a second identical cell which is charged using a 1C constant current (CC) - constant voltage (CV) procedure and discharged at a constant 1C rate. This paper describes the experiments performed and shows the impact high pulsed loading has on the aging and capacity fade of a high power lithium-ion battery after fifty cycles have been performed.
Design and Simulation of Spirally-Wound, Lithium-Ion Cells
Authors: Spotnitz Robert , Hartridge Steve , Damblanc Gaetan , Yeduvaka Gowri , Schad Don , Gudimetla Venugopal , Votteler Jeffrey , Poole Gene , Lueth Chris , Walchshofer Christian , Oxenham Evan
Published: July 2013

A general approach for the design of cylindrical and prismatic spirally-wound lithium-ion cells that accounts for arbitrary tabbing and coating patterns is presented. Examples are presented for design of high-power and high-energy 18650 size cells. For high-energy cells the current collector design is not critical while for high-power cells the tabbing design is significant especially when thermal effects are considered.
Cu-Sn Thin Film Production on Copper Substrate
Authors: Polat B. Deniz , Sezgin Nagihan , Keleş Özgul , Kazmanli Kursat , Abouimrane Ali , Amine Khalil
Published: July 2013

We investigated the anode performance of Cu-Sn thin film for lithium ion batteries. The results show that the presence of copper improves the cycleability of the thin film since the mechanical tolerance of the thin film against the stress generated during the high volumetric changes in lithiation/delithiation processes is increased.However, some improvement in the microstructure of the thin film is still required tofacilitate lithium movements in thin film structure and increase the cycle life of the electrode.
Electrolyte Performance of LiFTA-CsFTA Molten Salt for Lithium Secondary Battery
Authors: Kubota Keigo , Matsumoto Hajime
Published: July 2013

Introducing the Cs cation into a perfluorosulfonylamide lithium salt composed of (fluorosulfonyl)(trifluoromethylsulfonyl)amides (FTA−) effectively reduced both the melting point and viscosity. Especially, their eutectic mixture (Li0.4Cs0.6[FTA]) exhibited a wide liquid temperature range (33 ~ 200 °C), a wide electrochemical window (> 5.1 V), and the highest lithium ion partial conductivity among the Li-Cs mixtures. Furthermore, intercalation and deintercalation of lithium in and out of LiCoO2 and LiFePO4 positive electrodes could be observed in the eutectic melt with a high coulombic efficiency.
Polyfluorinated Electrolyte Solutions and Additives for High Voltage Non-Flammable Lithium Batteries
Authors: Sun Haoran , Wei Qiang
Published: July 2013

The highly flammable nature of current lithium battery electrolyte solution (hydrocarbons) presents a major challenge for operation at large scale, though significant efforts are being made to improve the battery safety and capacity. One of the key challenges for safe high voltage lithium batteries is to develop new electrolyte systems that are non-flammable and possess wide electrochemical windows. Here, we report the synthesis and fundamental electrochemical characterization of polyfluorinated electrolyte solutions and additives that could potentially be used in high voltage non-flammable lithium batteries. Our results show that the polyfluorinated electrolyte solutions we tested possess wider electrochemical windows than their hydrocarbon analogs, and are non-flammable. We further find that use of perfluorinated alcohol additives improves the reversibility of lithium ion reduction which is important for rechargeable lithium batteries. Together, polyfluorinated ethers and perfluorinated alcohols exhibit great potential in developing high voltage lithium batteries.
Wide Operating Temperature Range Electrolytes for High Voltage and High Specific Energy Li-Ion Cells
Authors: Smart Marshall C. , Hwang Constanza , Krause Frederick C. , Soler Jess , West William C. , Ratnakumar Bugga V. , Amine Khalil
Published: July 2013

A number of electrolyte formulations that have been designed to operate over a wide temperature range have been investigated in conjunction with layered-layered metal oxide cathode materials developed at Argonne. In this study, we have evaluated a number of electrolytes in Li-ion cells consisting of Conoco Phillips A12 graphite anodes and Toda HE5050 Li1.2Ni0.15Co0.10Mn0.55O2 cathodes. The electrolytes studied consisted of LiPF6 in carbonate-based electrolytes that contain ester co-solvents with various solid electrolyte interphase (SEI) promoting additives, many of which have been demonstrated to perform well in 4V systems. More specifically, we have investigated the performance of a number of methyl butyrate (MB) containing electrolytes (i.e., LiPF6 in ethylene carbonate (EC) + ethyl methyl carbonate (EMC) + MB (20:20:60 v/v %) that contain various additives, including vinylene carbonate, lithium oxalate, and lithium bis(oxalato)borate (LiBOB). When these systems were evaluated at various rates at low temperatures, the methyl butyrate-based electrolytes resulted in improved rate capability compared to cells with all carbonate-based formulations. It was also ascertained that the slow cathode kinetics govern the generally poor rate capability at low temperature in contrast to traditionally used LiNi0.80Co0.15Al0.05O2-based systems, rather than being influenced strongly by the electrolyte type.
Electrolytes with Improved Safety Developed for High Specific Energy Li-Ion Cells with Si-Based Anodes
Authors: Smart Marshall C. , Krause Frederick C. , Hwang Constanza , Soler Jess , West William C. , Bugga Ratnakumar V. , Prakash G. K. Surya
Published: July 2013

A number of electrolyte formulations that have improved safety characteristics have been developed for use with high capacity silicon-based anodes. To improve the compatibility with Si-based anodes, a number of technical approaches have been employed, including: (1) the use of mono-fluoroethylene carbonate (FEC) in conjunction with, or in lieu of, ethylene carbonate (EC), (2) the use of high proportions of fluorinated co-solvents, (3) the use of vinylene carbonate (VC) to stabilize the Si/C electrode, and (4) the use of lithium bis(oxalato)borate (LiBOB) to improve the compatibility of the electrolyte when Si/C electrodes are used in conjunction with high voltage cathodes. Candidate electrolytes were studied in Li/Si-C and Si-C/ Li(MnNiCo)O2 (NMC) coin cells, as well as in larger Si-C/NMC three-electrode cells equipped with lithium reference electrodes. In summary, many electrolytes that contain triphenyl phosphate (TPP), which is used as a flame retardant additive up to concentrations of 15 volume percent, and possess FEC as a co-solvent have been demonstrated to outperform the all-carbonate baseline electrolytes when evaluated in Si-C/ Li(MnNiCo)O2 cells.
Quantum Chemistry Study of the Oxidation-Induced Decomposition of Tetramethylene Sulfone (TMS) Dimer and TMS/BF4
-
Authors: Borodin Oleg , Jow T. Richard
Published: July 2013

Oxidation induced decomposition reactions of tetramethylene sulfone (TMS), its dimer and TMS/BF4
- complex were studied using M05-2X and LC-ωPBE density functionals in conjunction with polarized continuum model (PCM). Presence of anion or another TMS molecule near a TMS molecule was found to dramatically reduce barriers for the initial step of the oxidation decomposition reactions of TMS, changed the order of oxidation reactions and products. Specifically, the barrier for H-abstraction reaction TMS was reduced by from 0.9-1.0 eV for isolated TMS to 0.1-0.2 eV in the TMS dimer. Presence of BF4
- near TMS also reduced barriers for both TMS ring opening and H-abstraction reactions. The most kinetically active reactions were: a) TMS ring opening with fluorine transfer from BF4
- to the open TMS ring in the TMS/BF4
- complex and b) intramolecular H-transfer from a methylene group to the sulfone oxygen a TMS dimer, where the transfer was assisted by SO2-group from the neighboring TMS molecule. Ability of M05-2X and LC-ωPBE density functional to accurately describe TMS oxidation reactions was benchmarked through comparison with the composite G4MP2 theory.
Hydration and Structural Transformations during Titanium Anodization under Alkaline Conditions
Authors: Acevedo-Peña Próspero , Vázquez-Arenas Jorge G. , Cabrera-Sierra Roman , Lartundo-Rojas L. , González Ignacio
Published: July 2013

Ti anodic films were potentiostatically grown in 0.1 M NaOH aqueous solutions, in a potential range in which the voltammetric characterization showed an anodic shoulder related to the oxidation of TixOy (with y/x < 2) oxides. A variation in the density of donors and the flat band potential obtained by EIS measurements was related to changes in Ti suboxides proportion, confirmed by AR-XPS measurements. A modified Point Defect Model (PDM) was fitted to EIS experimental data in order to estimate the kinetic parameters describing the passivity of the Ti films. The model accounts for the formation and diffusion of oxygen and hydroxyl vacancies during film growth. The kinetic parameters related to film dehydration (e.g. hydroxyl vacancies) decrease as the formation potential becomes more positive, suggesting that the film hydration is crucial in the structure of the oxide grown during Ti anodization.
Corrosion of Nickel and Iron Based Superalloys in High Temperature Gas Environments
Authors: Yeh Tsung-Kuang , Chang Hao-Ping , Wang M. Y. , Kai J. J. , Yuan T.
Published: July 2013

High-temperature gas-cooled reactors (HTGRs) with helium gas asthe primary coolant have been considered as Generation IV nuclearpower reactor systems. Several iron- and nickel-based superalloys,including Incoloy 800H, Hastelloy X, and Inconel 617, arepotential structural materials in pressure boundary components,such as the intermediate heat exchanger (IHX) in an HTGR.Impurities in a helium coolant, such as H2O and O2, can interactwith structural materials at working temperatures of >900 oC,causing serious degradation. This study investigates the oxidationbehavior of three selected alloys (Hastelloy X, Incoloy 800H, andInconel 617) in high-temperature, gaseous environments withvarious levels of O2 and H2O. A series of corrosion tests wereconducted at test temperatures of 650 oC, 750 oC, 850 oC and 950oC under various coolant compositions of dry air, 1% O2, 10%humidity, and 50% humidity.
Effect of Sour Environment pH on Crack Morphology in Ultra-High Strength Drilling Steel Under Cyclic Stress
Authors: Ziomek-Moroz Malgorzata , Hawk Jeffrey A. , Thodla Ramgopal , Gui Feng
Published: July 2013

Catastrophic failure of a pre-cracked compact tension UD-165 sample after a cyclic stress versus frequency experiment in a 5% NaCl solution buffered with CO2/NaHCO3 and in contact with 0.83 MPa H2S at 20°C, pH=7, occurred in air. Only fatigue crack propagation was observed in a similar sample after a similar test in the pH=12 solution. The log fatigue crack rate measured as a function of log frequency for UD-165 in the pH=7 solution was linear with a gradient of -0.492 while in the pH=12 solution exhibited a plateau indicating different mechanisms based on fracture mechanics theory. The microscopic investigations of the sample after testing at pH=7 revealed the presence of fatigue cracks, initiated by sample pre-cracking. Also, on the surface of the catastrophically fractured base metal, pits and other secondary cracks were observed. The latter propagated along the beach marks. The surface analysis of UD-165 after testing in pH=12 solutions showed corrosion products covering the crack but not crack tip. Intergranular cracks were found on the surface of the fractured base metal in liquid nitrogen. The microscopic surface investigations corroborate the fracture mechanics results.
Effect of Galvanostatic Condition on Growth Behavior and Repassivation Potential of Crevice Corrosion of Duplex Stainless Steels
Authors: Aoki So , Ehashi Tatsuya , Sakai Jun'ichi
Published: July 2013

The purpose of this study is to clarify effect of galvanostatic condition on growth behavior and repassivation potential (E
R.CREV) of crevice corrosion of duplex stainless steels. E
R.CREV measurements, microscopic observation of corroded area, and solution pH measurements inside crevice were carried out. Under the condition of large holding current in propagation step of E
R.CREV measurements, the crevice corrosion grew from the bottom to the edge of crevice. Then, it grew towards depth direction, and the sharp corroded area formed near the edge of crevice. Solution pH inside crevice lowered easily under the condition of large holding current in repassivation step, and it induced the repassivation of corroding crevice at noble potential. It was suggested that the sharp corroded area formed near the edge of crevice under the large holding current condition contributed to lowering corrosivity of solution inside corroding crevice and the repassivation of corroding crevice at the noble potential.
Predicting the Steady State Thickness of Passive Films with the Point Defect Model in Fretting Corrosion Experiments
Authors: Geringer Jean , Taylor Matthew L. , Normand B. , Macdonald Digby D.
Published: July 2013

The goal is to calculate the steady state thickness of the oxides layer in order to know whether metal is protected or not. Thus thanks to experiments of fretting-corrosion with a sequence of Electrochemical Impedance Spectroscopy, it was possible to use these data with the PDM, Point Defect Model, and to reach the final goal: the prediction of the passive layer of the passive film. First of all, PDM was updated on the fretting process to yield the fretting Model. Thus after 100 minutes of fretting corrosion, the passive film is severely damaged from the modeling results by genetic algorithm. The increase of chlorides concentration allows the destruction of the passive films. However it has been showed that albumin does protect stainless steel against fretting-corrosion degradations. Modeling is in accordance with experiments where 0.1 M of NaCl is a threshold: wear volume was the highest and the steady state thickness the lowest.
Deterministic Prediction of Localized Corrosion Damage in Oil and Gas Pipelines
Authors: Engelhardt George R. , Woollam Richard C. , Macdonald Digby D.
Published: July 2013

In the general case, the prediction of localized corrosion damage can be made in statistical terms, for example, probability that the deepest pit will exceed a critical depth. However, the statistical parameters (mean depth of the deepest pit with its standard deviation, etc.) can be estimated deterministically (i.e. on the basis of the natural laws). In order to perform such a calculation, we require deterministic models for every stage of cavity propagation (pit nucleation, propagation and repassivation, transition pit into crack, crack propagation, etc.). Such an approach has been illustrated in this paper by predicting pitting damage in oil and gas pipelines. It is shown that repassivation phenomena, leading to pit repassivation (death), must be taken into account, in order to explain some experiential observations and to improve prediction of corrosion damage in pipelines by using results of short term experiments. Manipulation of the value of repassivation constant would seem to be the promising way of preventing pipeline failures.
Mathematical Models for Under-Deposit Corrosion in Aerated Media
Authors: Chang Ya-Chiao , Orazem Mark E.
Published: July 2013

A three-dimensional mathematical model was developed to investigate conditions under which the onset of under-deposit corrosion occurs. A model for corrosion in the fluids containing dissolved oxygen is presented. The location of anodic and cathodic regions was not assumed a priori, but was rather the result of the numerical simulation, which revealed galvanic coupling caused by the formation of differential aeration cells. The model accounts for electrochemical reactions, homogeneous reactions, and deposition of reaction products which influenced the rate of the electrochimical reactions and resulted in an active-passive transition.
Corrosion Behavior of Mild Steel Alloy A537 Used As Canister Material for Nuclear Waste Storage
Authors: Grant John , Chidambaram Dev
Published: July 2013

The interaction between mild steel nuclear waste storage containers and technetium ions is not well understood. Technetium is often found as an oxidized pertechnetate (TcO4
-) anion at nuclear waste storage sites. This study is aimed at identifying whether TcO4
- anions present a corrosion risk to mild steel nuclear waste storage tanks. The interaction of mild steel alloy A537 class 1 with rhenium, a technetium surrogate, was studied. Potentiodynamic polarization tests evaluated electrochemical behavior and the surface morphology was studied using scanning electron microscopy and optical microscopy. Potentiodynamic polarization experiments were conducted in 1.0M NaNO3 + 0.1M NaOH and 1.0M NaNO3 + 0.1M NaOH + 0.02M NaReO4. Three different temperatures were used in testing, namely, (i) ambient temperature, (ii) 50oC and (iii) 80oC. Sodium perrhenate was observed to inhibit the corrosion of the mild steel A537 samples. However, corrosion rates were found to increase with increasing temperatures both in the presence and absence of perrhenate.
Determination of Kinetic Parameters for Water Reduction on Copper
Authors: Sharifi(Asl) Samin , Macdonald Digby D.
Published: July 2013

In this study, the effects of temperature, solution pH, and hydrogen pressure on the kinetics of hydrogen electrode reaction (HER) have been studied by means of steady-state polarization measurements on copper in borate buffer solution. In order to obtain electrokinetic parameters, such as the exchange current density and cathodic Tafel slope, two stages of optimization have been performed. From the optimization process, the apparent activation energy (Eac
) of HER on copper was obtained as 32(kJ/mol). Moreover, the exchange current density i0(H2) and the cathodic transfer coefficient were obtained on copper as a function of temperature, solution pH, and hydrogen pressure.
State of Health Estimation of LiFePO4/Graphite Cells
Authors: Zhang Yancheng , Wang Chao-Yang
Published: July 2013

A new method is proposed to estimate state of health (SoH) of LiFePO4/graphite cells using partial charge capacity (PCC) between 3.5 and 3.6 V. A degradation index (DI), defined as the ratio of the current PCC to the initial PCC (for a fresh cell) at the same conditions, is found to linearly correlate with the SoH. The PCC is measured at constant current charging, which can readily be implemented and is much easier than using discharge diagnosis dependent on road and driving conditions. This method only needs to record charging time between 3.5 and 3.6 V during constant current charging, but does not require full discharge before the charging and any additional sensors or complex computations of model-based approaches. Consequently, it is an efficient and simple method to estimate the SoH of LiFePO4/graphite cells by using the PCC-based degradation index.
Overview of the Mg Corrosion Mechanism
Authors: Atrens Andrej
Published: July 2013

Our recently developed plug-in specimens allow direct comparison between corrosion rates measured by weight loss, hydrogen evolution and from Tafel extrapolation of polarization curves. These have allowed identification of some of the reasons why Tafel extrapolation has previously not provided a good measure of steady state corrosion for Mg, because: (i) of crevice corrosion in the specimen mount, (ii) of decoupling of the Mg corrosion from the electrochemical measurements; and (iii) Tafel extrapolation has often been used to study Mg corrosion soon after specimen insertion into the solution, despite the fact that it is well known that Mg alloy corrosion is often non-linear, the corrosion rate accelerates to a steady state rate after an initial period of low corrosion rate
The Palladium Hydrogen System; Corrosion Monitoring and Energy Production
Authors: McKubre Michael Charles , Bao Jianer , Crouch-Baker Steven , Jayaweera Palitha , Sanjurjo Angel , Tanzella Francis
Published: July 2013

Initial efforts to characterize the resistance-loading relationship for hydrogen and its isotopes in palladium lead to a much more intensive examination of this property following the 1989 announcement by Fleischmann and Pons of putative “cold fusion”. Subsequent work lead to an understanding of the loading requirement for the Fleischmann Pons heat effect (FPHE) enabling rationalization of earlier failed attempts to observe this effect.
Development of Zn-Mn Alloy Based Sacrificial Coatings
Authors: Ganesan Selvarani , Prabhu Ganesan , Popov Branko N.
Published: July 2013

Electrodeposition of Zn-Mn alloys were carried out in an acidic chloride bath. The influence of electrolytic bath composition and deposition parameters on the alloys’ composition, cathodic current efficiency and corrosion properties were examined. It was found that the composition of plating baths and deposition potential have significant effect on manganese content and Zn-Mn deposit morphology, as well as on the corrosion properties of the alloy. Linear and Tafel polarization studies showed that the incorporation of Mn in the Zn enhances the corrosion resistance when compared to bare Zn. Anodic passivation studies indicated two orders of magnitude lower passivation current for the Zn-Mn alloy (17% Mn) when compared to that of Zn.
Mechanistic Evaluation of SCC in Sensitized and Unsensitized Specimens of AA5083 Using Localized Probing Techniques
Authors: Williams Krystaufeux , Bayles Robert , Natishan Paul M. , Macdonald Digby D.
Published: July 2013

When as-received or sensitized AA5083 are immersed in an electrolyte, a growing crack creates a galvanic couple with the external surfaces according to the differential aeration hypothesis. Monitoring the resulting “coupling current” yields information about the mechanisms of crack advance. The purpose of this study is to determine if the scanning vibrating electrode technique (SVET) can be used to monitor the coupling current flowing through the solution from the crack to the external surfaces. If successful, this method, which maps potential as a function of probe position via a scanning vibrating probe (SVP), can be used to visualize and quantify the coupling current emanating from a growing stress corrosion crack in sensitized and unsensitized aluminum alloy samples to yield more localized information about the crack growth process. Preliminary feasibility studies were performed to map the current/potential in larger galvanic couples designed to simulate Cu-rich intermetallics dispersed in an aluminum matrix (as in the Cu-rich particles in AA2024 and Mg-rich intermetallics in AA5083). A fracture mechanics apparatus, designed to apply a known stress intensity, was employed to reveal the onset of subcritical crack growth. The final goal is to combine the typical fracture mechanics testing with the SVET and acoustic emissions. We report on the progress that has been made in designing a customized four-point bend, fracture mechanics device that allows for simultaneous loading and electrochemical mapping. Future work will report data gathered from in-situ electrochemical and acoustic emissions testing on pre-cracked AA5083 specimens.
Corrosion of Iron in Physically-Constrained Locations
Authors: Macdonald Digby D. , Kursten Bruno , Engelhardt George R.
Published: July 2013

A model has been developed to calculate the impact of the porous, outer layer of the passive film on the corrosion rate of the carbon steel overpack and on the structural integrity of the concrete in the annulus of the super container of the Belgian High Level Nuclear Waste (HLNW) disposal concept. Because the corrosion product occupies 2 – 6.5 times the volume of the iron from which it forms the development of the outer layer in the confined space between the carbon steel overpack and the concrete will result in the compression of the outer layer and a concomitant decrease in the porosity. If the porosity decreases to a sufficiently low value, the growth of the outer layer ceases and further corrosion is prevented. If the thickness of the corroded layer exceeds a critical value, the concrete will crack, because of the poor strength of cementations materials under tensile loading.
Metal-Assisted Chemical Etching of Silicon Using Oxygen as an Oxidizing Agent: Influence of HF Concentration on Etching Rate and Pore Morphology
Authors: Yae Shinji , Morii Yuma , Enomoto Masato , Fukumuro Naoki , Matsuda Hitoshi
Published: July 2013

Metal-assisted chemical etching of silicon is an electroless method that can produce porous silicon by immersing metal-modified silicon in a HF solution without electrical bias. We have been studying this etching using dissolved oxygen as an oxidizing agent and recently reported that the catalytic activity of noble metal particles including silver, gold, platinum, and rhodium, influences the cathodic reduction of oxygen and controls the etching rate. In this paper, we investigate the influence of the HF concentration on the etching rate and the pore morphology. In the case of high HF concentration, the etching rate is independent of the HF concentration and depends on the oxygen concentration and the catalytic activity of the metal particles. In the low HF concentration case, the etching rate depends on the HF concentration and is independent of the oxygen concentration and the catalytic activity. The pore morphology is also changed by the HF concentration.
Morphological Development from Uniform Microporous Structure to Macropore-Like Structure
Authors: Urata Tomoko , Fukami Kazuhiro , Sakka Tetsuo , Ogata Yukio H.
Published: July 2013

Porous silicon is formed by electrochemical anodization in HF solution. Morphological development from a microporous structure with framework (skeleton structure) to a macroporous structure was studied. A skeleton structure can be obtained when some types of organic solvents are used. The skeleton structure changes to a macroporous structure when concentration of HF in solution decreases. Macropore formation is also observed at high current density in high-concentration HF solution. Two possible paths are proposed for each development. The skeleton structure seems to be an important key to discuss macropore formation.
Pore Formation in InP Anodized in KOH: Effect of Temperature and Concentration
Authors: Quill Nathan , Lynch Robert P , O'Dwyer Colm , Buckley Denis Noel
Published: July 2013

The effect of both temperature and electrolyte concentration on the formation of porous layers in InP is explored. Pore width, porous layer thickness and porosity decrease with increasing temperature and show a minimum at intermediate KOH concentrations, increasing as concentration is either increased or decreased from that value. The variations in pore width and layer thickness are correlated: thinner pores appear to limit layer thickness, presumably by influencing mass transport throughout the porous network. A three step model of charge transfer at the semiconductor/electrolyte interface is used to explain these observations.
Near Infrared Heat Treatment to Flow Melt Tinplate
Authors: Mabbett Ian , Geary Steven , Warren David John , Sullivan James H. , Penney David , Watson Trystan M. , Worsley David A.
Published: July 2013

Tinplate is often reflowed during production to improve surface finish and promote diffusion resulting in an iron-tin intermetallic layer. This is done currently using a combination of induction and resistance heating. Near Infrared (NIR) has been used to rapidly heat metal substrates to high temperatures for application in roll to roll production of photovoltaic devices and also in reflowing of galvanized coatings on steel. In this work the NIR technique is applied to flow melting in tinplate, showing that a non-contact method exists that can reflow tin in less than three seconds. Since it is non-contact this method is suitable for batch annealing products after they are formed into complex shapes.
Bronchoconstriction induced by increasing airway temperature in ovalbumin-sensitized rats: role of tachykinins
Authors: Hsu Chun-Chun , Lin Ruei-Lung , Lin You Shuei , Lee Lu-Yuan
Published: July 2013

This study was carried out to determine the effect of allergic inflammation on the airway response to increasing airway temperature. Our results showed the following: 1) In Brown-Norway rats actively sensitized by ovalbumin (Ova), isocapnic hyperventilation with humidified warm air (HWA) for 2 min raised tracheal temperature (Ttr) from 33.4 ± 0.6°C to 40.6 ± 0.1°C, which induced an immediate and sustained (>10 min) increase in total pulmonary resistance (Rl) from 0.128 ± 0.004 to 0.212 ± 0.013 cmH2O·ml−1·s ( n = 6, P < 0.01). In sharp contrast, the HWA challenge caused the same increase in Ttrbut did not generate any increase in Rl in control rats. 2) The increase in Rl in sensitized rats was reproducible when the same HWA challenge was repeated 60–90 min later. 3) This bronchoconstrictive effect was temperature dependent: a slightly smaller increase in peak Ttr(39.6 ± 0.2°C) generated a significant but smaller increase in Rl in sensitized rats. 4) The HWA-induced bronchoconstriction was not generated by the humidity delivered by the HWA challenge alone, because the same water content delivered by saline aerosol at room temperature had no effect. 5) The HWA-evoked increase in Rl in sensitized rats was not blocked by atropine but was completely prevented by pretreatment either with a combination of neurokinin (NK)-1 and NK-2 antagonists or with formoterol, a β2agonist, before the HWA challenge. This study showed that increasing airway temperature evoked a pronounced and reversible increase in airway resistance in sensitized rats and that tachykinins released from the vagal bronchopulmonary C-fiber endings were primarily responsible.
Surfactant reduction of cerebral infarct size and behavioral deficit in a rat model of cerebrovascular arterial gas embolism
Authors: Eckmann David M. , Armstead Stephen C.
Published: July 2013

Gas embolism occurs commonly in cardiac and vascular surgery and decompression sickness. The goals of this study were to develop a new in vivo rat model of cerebrovascular arterial gas embolism and to determine the effects of exogenous surfactants on resultant brain infarct volume and accompanying long-term neurological dysfunction using the model. Unilateral cerebral arterial gas embolism was induced in Sprague Dawley rats, including groups receiving intravenous Pluronic F-127 (PF-127) and Oxycyte perflourocarbon surfactant pretreatment. Magnetic resonance imaging (MRI) was performed at 24 and 72 h postembolism to determine infarct volume. The elevated body swing test (EBST), limb-placement test, proprioception forelimb and hindlimb tests, whisker tactile test, and Morris Water Maze test were performed to assess motor behavior, somatosensory deficit, and spatial cognitive function out to 29 days after embolization. A stable stroke model was developed with MRI examination revealing infarction in the ipsilateral cerebral hemisphere. Gas embolized rats had significant cognitive and sensorimotor dysfunction, including approximately threefold increase in Morris Water Maze latency time, ∼20% left-sided biasing in EBST performance, 0.5 to 1.5 (mean) point score elevations in the proprioception and whisker tactile tests, and 3.0 point (mean) elevation in the limb-placement test, all of which were persistent throughout the postembolic period. Surfactant prophylaxis with either PF-127 or Oxycyte rendered stroke undetectable by MRI scanning and markedly reduced the postembolic deficits in both cognitive and sensorimotor performance in treated rats, with normalization of EBST and whisker tactile tests within 7 days.
Diagnostic Usefulness of MUC1 and MUC4 for Distinguishing between Metastatic Adenocarcinoma Cells and Reactive Mesothelial Cells in Effusion Cell Blocks
Authors: Cho Jin Seong , Kim Ga-Eon , Lee Ji Shin , Lee Jae Hyuk , Nam Jong Hee , Choi Chan
Published: July 2013

Objective: The aim of our study was to determine the diagnostic value of MUC1 and MUC4 for distinguishing between metastatic adenocarcinoma cells (MAC) and reactive mesothelial cells (RMC) in effusion fluids. Study Design: A total of 237 cell block specimens from pleural and peritoneal effusions, including 196 malignant effusions with MAC and 41 benign effusions with RMC, were stained with antibodies against MUC1 and MUC4. Membranous staining with or without cytoplasmic staining was considered to be positive. Results: MUC1 immunoreactivity was observed in 194 (99.0%) of 196 cases of MAC and in 20 (48.8%) of 41 cases of RMC. MUC4 immunoreactivity was observed in 174 (88.8%) of 196 cases of MAC and in 4 (9.8%) of 41 cases of RMC. For distinguishing MAC from RMC, the MUC1 reactivity was found to be 99.0% sensitive and 51.2% specific with a positive predictive value of 90.7% and a negative predictive value of 91.3%. The sensitivity of MUC4 for MAC was 88.8%, the specificity was 90.2%, the negative predictive value was 62.7%, and the positive predictive value was 97.8%. Conclusion: Our data suggest that MUC4 appears to be a sensitive and specific marker for differentiating between MAC and RMC.
Liquid-Based Cytology of the Breast: Pitfalls Unrecognized before Specific Liquid-Based Cytology Training - Proposal for a Modification of the Diagnostic Criteria
Authors: Feoli Francesco , Ameye Lieveke , Van Eeckhout Pascal , Paesmans Marianne , Marra Vincenzo , Arisio Riccardo
Published: July 2013

Objectives: To describe the pitfalls encountered in switching over from conventional smears (CSm) to liquid-based cytology (LBC). To explore modifications of our usual diagnostic criteria. Study Design: 190 ThinPrep breast samples with paired biopsies were retrospectively evaluated by two breast cytopathologists experienced only in CSm. They were again studied after LBC training. The diagnostic performances were compared. In additional calculations we included those C4/suspicious samples containing 70% high-grade nuclei and up to 30% nonmalignant cells in the C5/positive category, simulating that they harbored a malignant one-cell population. We prospectively validated this modification of our diagnostic criteria. Results: Training resulted in higher complete sensitivity: 94 versus 86% (p value 0.003) and lower false negative ratio: 4 versus 12% (p value 0.003). Training generated higher complete sensitivity than collaboration without training: 94 versus 89% (p value 0.008). In the simulation, the modified criteria increased absolute sensitivity to 74% with a 0.6% false positive rate. In the validation series, they generated up to 91% absolute sensitivity, 12% suspicious rate and no false negative and false positive diagnoses. Conclusion: Training in breast LBC may increase diagnostic performance. Samples containing 70% high-grade nuclei or more can be categorized as malignant.
Differential Diagnosis of Reactive Mesothelial Cells and Malignant Mesothelioma Cells Using the Cell Proliferation Markers Minichromosome Maintenance Protein 7, Geminin, Topoisomerase II Alpha and Ki-67
Authors: Kimura Fumikazu , Okayasu Isao , Kakinuma Hirokuni , Satoh Yukitoshi , Kuwao Sadahito , Saegusa Makoto , Watanabe Jun
Published: July 2013

Objective: The aim of this study was to evaluate whether the immunocytochemical expression of cell proliferation markers, such as minichromosome maintenance protein 7 (MCM 7), geminin, topoisomerase II alpha (topo IIα) and Ki-67, which are different types of cell proliferation markers, could be useful for their differential diagnosis in reactive mesothelial cells and malignant mesothelioma cells obtained from body cavity fluids. Study Design: Samples diagnosed and later histologically confirmed as reactive mesothelial cells (39 cases) or malignant mesothelioma (32 cases) in body cavity fluids were examined. Immunocytochemical staining of MCM 7, geminin, topo IIα and Ki-67 was performed with the immunoperoxidase polymer method. Results: Labeling indices (LIs) of MCM 7 (cutoff value 20.0%; sensitivity 100%; specificity 100%), geminin (cutoff value 4.5%; sensitivity 88.0%; specificity 70.0%), topo IIα (cutoff value 11.0%; sensitivity 88.0%; specificity 92.0%) and Ki-67 (cutoff value 15.3%; sensitivity 78.0%; specificity 79.0%) of malignant mesothelioma cells were significantly higher than those of reactive mesothelial cells. Conclusion: LIs of MCM 7, geminin and topo IIα can be reliable tools for the differential diagnosis of reactive mesothelial cells and malignant mesothelioma cells.
Fine Needle Aspiration Cytopathology of Liver Masses: 101 Cases with Cyto-/Histopathological Analysis
Authors: Kaçar Özkara Sevgiye , Özöver Tuneli İrem
Published: July 2013

Objective: Appropriate clinical management of a hepatic mass depends on its accurate diagnosis. We aimed to evaluate sensitivity, specificity and accuracy of percutaneous fine needle aspiration cytopathology (FNAC) in the diagnosis of suspicious liver masses in our center. Study Design: Cytopathology and histopathology databases were searched for patients undergoing combined, image-guided percutaneous FNAC and biopsy sampling of liver mass lesions in 2006-2011. All patients had one or more radiologically detected lesion and clinical suspicion of neoplastic disease. Sensitivity, specificity and accuracy of FNAC in the diagnosis of liver lesions were determined using histopathological diagnoses on liver biopsy as a gold standard. Results: Of 101 patients, cytopathological diagnoses were nonneoplastic in 10 cases while 10 cases were suspicious for neoplasms and 71 were malignant. In 10 patients (9.9%), FNA samples were inadequate for assessment. Final histopathological diagnoses were nonneoplastic in 7 cases, benign tumoral in 5 and malignant in 89 cases (88.1%). Of the malignancies, 22 (24.7%) were hepatocellular carcinomas (HCC) and 60 (67.4%) were metastatic tumors on final clinicohistopathological analysis. The remaining 7 (7.8%) patients had other primary hepatic malignancies. Fifteen of the 22 (68.2%) HCC cases were specifically diagnosed by FNAC. In 28 of the metastatic tumors, the primary organ site was unknown, followed by gastrointestinal malignancies in 17 cases. Overall, sensitivity, specificity, accuracy, and positive and negative predictive values of FNAC in the diagnosis of neoplastic lesions were 96.3, 90.0, 95.6, 98.7 and 75.0%, respectively. Discrepancy in cyto-/histopathological data was mainly seen in nonrepresentative FNAC cases. Conclusion: FNAC of liver masses is a highly accurate technique that can be used to identify the majority of primary/metastatic hepatic neoplasias with high specificity. A combined cyto-/histopathological approach provides higher accuracy in the diagnosis and typing of hepatic tumors, which may affect therapeutic decisions. Correlation of cytopathology with clinicoradiological findings is helpful to increase overall accuracy of the procedure.
Metastatic Renal Cell Carcinoma to the Pancreas: Diagnostic Significance of Fine-Needle Aspiration Cytology
Authors: Gilani Syed M. , Tashjian Randy , Danforth Robert , Fathallah Lamia
Published: July 2013

Background: Renal cell carcinoma rarely metastasizes to the pancreas. Diagnosing a neoplasm that is metastatic to the pancreas by fine-needle aspiration (FNA) cytology is often challenging. A detailed clinical history may prove to be beneficial. Case Reports: A total of 729 pancreatic FNAs were performed from January 2005 through August 2012 at our institution. Among these, we found 3 patients with a prior history of a malignant renal neoplasm who presented with a pancreatic mass: 2 in the tail and 1 in the head. Radiographically, they ranged in size from 2.5 to 7.0 cm. Microscopic evaluation of cytologic material obtained during endoscopic ultrasound-guided FNA (EUS-FNA) revealed cohesive clusters of atypical cells with clear cytoplasm and prominent nucleoli surrounded by a thin capillary network. The neoplastic cells were immunoreactive with CD10 (cases 2 and 3). A diagnosis of metastatic clear cell renal cell carcinoma was rendered for each case based on the morphologic features and immunohistochemical staining pattern of the neoplastic cells. Histologic comparison with the available slides of the corresponding primary renal neoplasm confirmed the diagnosis. Conclusion: We conclude that EUS-FNA of pancreatic masses is an important, effective, and accurate diagnostic modality for early diagnosis of both primary and metastatic neoplasms of the pancreas.
Rehydration of Air-Dried Smears versus Wet Fixation: A Cross-Sectional Study
Authors: Rupinder Kaur , Shubra Walia , Kanwal Masih
Published: July 2013

Background: The Papanicolaou (Pap) smear is an effective method for early detection of cervical cancer. The routine practice of staining is to immediately fix the cervical smear in 95% ethyl alcohol. An alternative method of rehydrating the air-dried cervical smears followed by fixation and conventional staining method can overcome most of the problems associated with short supply and storage of alcohol, wet fixing of slides and transporting them to the cytology centre if the Pap smears are prepared at a peripheral centre. There are only few studies regarding rehydration of cervical smears as a substitute for wet fixation. Aim: The current study was undertaken to assess this technique as an alternative method for conventional wet-fixed smears. Material and Methods: This study was done over a period of 15 months in a tertiary care setup. Two sets of 461 cervical smears were examined; the smears in the first set were fixed in 95% ethyl alcohol and the other set of 461 smears was air dried, rehydrated and then fixed in 95% ethyl alcohol. Both the smears were stained with Pap stain, examined for preservation of cytomorphological features and evaluated using the modification of parameters given by Ng et al. [Acta Cytologica 1994;38:56-64]. Results and Analysis: Two sets of 461 smears each, one air dried and rehydrated and the other wet fixed in alcohol, were evaluated for cytomorphological preservation, and comparison was done. In wet-fixed smears, morphology was excellent in the majority of cases (80.7%). Cytomorphology was optimal in 18% and suboptimal in 1.3% of the cases. The air-dried and rehydrated smears showed excellent morphological preservation in 67%, followed by 29.9% optimal and 2.8% suboptimal preservation. The p value was >0.05, which was not significant. Conclusion: Rehydration, followed by fixation of air-dried smears, is a simple, feasible, applicable and reliable fixation technique which is comparable to the wet-fixed conventional technique used for cervical smears and can be applied for evaluation on a routine basis.
Regulation of STIM1/Orai1-dependent Ca2+ signalling in platelets
Authors: Münzer Patrick , Gawaz Meinrad , Borst Oliver , Lang Florian
Published: July 2013

Platelet secretion and aggregation as well as thrombus formation of blood platelets critically depend on increase of cytosolic Ca2+ concentration ([Ca2+]i) mainly resulting from intracellular Ca2+ release followed by store operated Ca2+ entry (SOCE) through Ca2+ release activated channels (CRAC). SOCE is in part accomplished by the pore forming unit Orai and its regulator stromal interaction molecule (STIM). Orai1 and STIM1 transcription is stimulated by NFkB (nuclear factor kappa B). Serum- and glucocorticoid-inducible kinase 1 (SGK1) up-regulates NFkB-activity in megakaryocytes and thus Orai1- expression and SOCE in platelets. SGK1 is thus a powerful regulator of platelet Ca2+-signalling and thrombus formation and presumably participates in the regulation of platelet activation by a variety of hormones as well as clinical conditions (e.g. type 2 diabetes or metabolic syndrome) associated with platelet hyperaggregability and increased risk of thromboocclusive events. SOCE in platelets is further regulated by scaffolding protein Homer and chaperone protein cyclophilin A (CyPA). Additional potential regulators of Orai1/STIM1 and thus SOCE in platelets include AMP activated kinase (AMPK), protein kinase A (PKA), reactive oxygen species, lipid rafts, pH and mitochondrial Ca2+ buffering. Future studies are required defining the significance of those mechanisms for platelet Orai1 abundance and function, for SOCE into platelets and for platelet function in cardiovascular diseases.
More than a simple storage organ: Adipose tissue as a source of adipokines involved in cardiovascular disease
Authors: Rega-Kaun Gersina , Kaun Christoph , Wojta Johann
Published: July 2013

Overweight and obesity in many countries have developed into a serious health problem by themselves and by their impact on other pathologies such as insulin resistance, type 2 diabetes, hypertension, heart disease and cancer. The modulation of these diseases by adipose tissue-derived biomolecules, so-called adipokines, could be the key to differentiate between metabolically healthy and unhealthy obesity. This review will discuss the pathophysiological role of selected adipokines, primarily focusing on cardiovascular diseases. Furthermore, we will highlight possible therapeutic approaches, which target these biomolecules.