bluuebunny/crossref_metadata_2025 huggingface dataset:
Mortality and morbidity meetings: an untapped resource for improving the governance of patient safety?
Authors: Higginson Juliet , Walters Rhiannon , Fulop Naomi
Published: May 2012

Introduction

National Health Service hospitals and government agencies are increasingly using mortality rates to monitor the quality of inpatient care. Mortality and Morbidity (M&M) meetings, established to review deaths as part of professional learning, have the potential to provide hospital boards with the assurance that patients are not dying as a consequence of unsafe clinical practices. This paper examines whether and how these meetings can contribute to the governance of patient safety.

Methods

To understand the arrangement and role of M&M meetings in an English hospital, non-participant observations of meetings (n=9) and semistructured interviews with meeting chairs (n=19) were carried out. Following this, a structured mortality review process was codesigned and introduced into three clinical specialties over 12 months. A qualitative approach of observations (n=30) and interviews (n=40) was used to examine the impact on meetings and on frontline clinicians, managers and board members.

Findings

The initial study of M&M meetings showed a considerable variation in the way deaths were reviewed and a lack of integration of these meetings into the hospital's governance framework. The introduction of the standardised mortality review process strengthened these processes. Clinicians supported its inclusion into M&M meetings and managers and board members saw that a standardised trust-wide process offered greater levels of assurance.

Conclusion

M&M meetings already exist in many healthcare organisations and provide a governance resource that is underutilised. They can improve accountability of mortality data and support quality improvement without compromising professional learning, especially when facilitated by a standardised mortality review process.
Scoring the percentage of Ki67 positive nuclei is superior to mitotic count and the mitosis marker phosphohistone H3 (PHH3) in terms of differentiating flat lesions of the bladder mucosa
Authors: Gunia Sven , Kakies Christoph , Erbersdobler Andreas , Koch Stefan , May Matthias
Published: May 2012

Aims

To systematically compare different approaches for evaluating mucosal proliferative activity regarding their diagnostic role for delineating flat lesions of the bladder mucosa.

Methods

32 carcinoma in situ (CIS) and 31 flat non-CIS conditions (low-grade dysplasia and reactive atypia) of the bladder mucosa were assessed by two independent pathologists in two rounds in terms of their proliferative activity assessed by the mitotic counts on H&E-stained sections (mitoses per mm2) and immunohistochemically using the MIB-1 antibody and the mitosis marker phosphohistone H3 (PHH3). Two different approaches for immunoscoring (percentage of stained nuclei vs dichotomised height of mucosal staining considering lower half vs full-thickness marker expression) were applied. κ statistics were used to evaluate interobserver and intraobserver reproducibility.

Results

Scoring the percentage of Ki67 expressing cell nuclei seems to be superior to dichotomisation of the height of mucosal staining as well as to PHH3 immunostaining and conventional mitotic counts in terms of delineating CIS from flat non-CIS conditions. This approach shows substantial (κ=0.62–0.65; p<0.001) interobserver and substantial to almost perfect (κ=0.67–0.83; p<0.001) intraobserver reproducibility.

Conclusions

The MIB-1 antibody is a useful adjunct in the differential diagnosis of conventionally challenging flat lesions of the bladder mucosa. In particular, 16% or more Ki67 positive cell nuclei favours CIS over flat non-CIS conditions, whereas 15% or less Ki67 positive cell nuclei is supportive of non-CIS conditions. However, due to some important limitations of MIB-1 staining, the MIB-1 antibody should be used as a component of a panel.
Absence of extramural venous invasion is an excellent predictor of metastasis-free survival in colorectal carcinoma stage II—a study using tangential tissue sectioning
Authors: Dirschmid Klaus , Sterlacci William , Oellig Frank , Edlinger Michael , Jasarevic Zerina , Rhomberg Michaela , Dirschmid Harald , Offner Felix
Published: May 2012

Aims

Extramural venous invasion (EVI) is an important predictor of haematogenous metastasis in colorectal cancer (CRC). However, remarkable discrepancies in incidence rates indicate major problems regarding EVI assessment. The present prospective study applies tangential vessel preparation to CRC resection specimens and correlates results of EVI with metachronous haematogenous metastatic (MHM) spread.

Methods

Stage II CRC diagnosed at the Institute of Pathology, University Teaching Hospital Feldkirch, Austria over a period of 30 months were analysed and tangential sectioning of the pericolonic tissue was performed. Confirmation, or exclusion of MHM, as assessed by computerised tomography, sonography or biopsy, was recorded.

Results

In 50/79 (63%) cases EVI was detected. In 13/50 (26%), MHM developed. Of the 29/79 (37%) patients without EVI, only one (3.5%) developed MHM. Statistically, the rate of MHM for patients with EVI was independent of adjuvant chemotherapy.

Conclusions

Tangential sectioning of the tumour periphery in CRC stage II yields a high rate of histologically evaluable extramural veins and permits proper assessment of EVI. Absence of EVI is significantly associated with metastasis-free survival, a finding of potential therapeutic value. On the other hand, one-third of the patients with EVI and circumferential tumour growth develop MHM, a setting in which the option for adjuvant chemotherapy should be considered. This study emphasises the importance of tangential sectioning of the invasive tumour front in CRC compared with the recommended perpendicular technique. The sensitivity and specificity of this method regarding MHM are characterised.
Coexistence of Gilbert syndrome with hereditary haemolytic anaemias
Authors: Rawa Katarzyna , Adamowicz-Salach Anna , Matysiak Michał , Trzemecka Anna , Burzynska Beata
Published: May 2012

Background

Gilbert syndrome is an inherited disease characterised by mild unconjugated hyperbilirubinaemia caused by mutations inUGT1A1gene which lead to decreased activity of UDP-glucuronosyltransferase 1A1. The most frequent genetic defect is a homozygous TA dinucleotide insertion in the regulatory TATA box in theUGT1A1gene promoter.

Methods and results

182 Polish healthy individuals and 256 patients with different types of hereditary haemolytic anaemias were examined for the A(TA)nTAA motif. PCR was performed using sense primer labelled by 6-Fam and capillary electrophoresis was carried out in an ABI 3730 DNA analyser. The frequency of the (TA)7/(TA)7genotype in the control group was estimated at 18.13%, (TA)6/(TA)7at 45.05% and (TA)6/(TA)6at 36.26%. There was a statistically significant difference in the (TA)6/(TA)6genotype distribution between healthy individuals and patients with glucose-6-phosphate dehydrogenase deficiency (p=0.041). Additionally, uncommon genotypes, (TA)5/(TA)6, (TA)5/(TA)7and (TA)7/(TA)8of the promoter polymorphism, were discovered.

Conclusion

Genotyping of theUGT1A1gene showed distinct distribution of the common A(TA)nTAA polymorphism relative to other European populations. Because of a greater risk of hyperbilirubinaemia due to hereditary haemolytic anaemia, the diagnosis of Gilbert syndrome in this group of patients is very important.
Glutamate and GABA in the medial amygdala induce selective central sympathetic/parasympathetic cardiovascular responses
Authors: Neckel Helinton , Quagliotto Edson , Casali Karina R. , Montano Nicola , Dal Lago Pedro , Rasia-Filho Alberto A.
Published: May 2012

Glutamate and γ-aminobutyric acid (GABA) participate in central cardiovascular control, and are found in the rat posterodorsal medial amygdala (MePD), an area of the forebrain that modulates emotional/social behaviors. Here we tested whether these neurotransmitters in the MePD could change the basal activity, chemoreflex, and baroreflex cardiovascular responses in awake rats. Power spectral analysis and symbolic analysis were used to evaluate these responses. Microinjections of saline, glutamate (2 µg), or GABA (61 ng or 100 µg; n = 5–7 rats per group) did not affect basal parameters or chemoreflex responses. However, baroreflex responses showed marked changes. Glutamate increased power spectral and symbolic sympathetic indexes related to both cardiac and vascular modulations (P < 0.05). In turn, the displacement of the baroreflex half-maximal heart rate (HR) response was associated with a GABA (61 ng) mediated decrease in the upper plateau (P < 0.05). Administration of GABA (61 ng, but not 100 µg) also increased HR variability (P < 0.05), in association with parasympathetic activation. These data add novel evidence that the MePD can promote selective responses in the central regulation of the cardiovascular system, i.e., glutamate in the MePD evoked activation of a central sympathetic reflex adjustment, whereas GABA activated a central parasympathetic one.
Metabolic and genetic factors modulating subject specific LDL-C responses to plant sterol therapy1This article is an invited review for the Journal's Made In Canada section. The authors gratefully acknowledge the training that was acquired at the Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba. We would specifically like to thank Dr. Peter Jones for his mentorship and significant contribution to the research contained within this manuscript.
Authors: Rideout Todd C. , Harding Scott V. , Mackay Dylan S.
Published: May 2012

Reducing intestinal cholesterol absorption with plant sterol consumption is a well-characterized strategy to lower LDL-C and potentially reduce cardiovascular disease risk. However, over 50 years of clinical research demonstrate that there is significant heterogeneity in the individual LDL-C lowering response to plant sterol therapy. A clear understanding of why plant sterols work effectively in some individuals but not in others will ensure optimal integration of plant sterols in future personalized nutritional lipid-lowering strategies. This review will examine the current knowledge base surrounding the metabolic and genetic determinants of LDL-C lowering in response to plant sterol consumption.
RELATIVISTIC PARTICLE IN ELECTROMAGNETIC FIELDS WITH A GENERALIZED UNCERTAINTY PRINCIPLE
Authors: MERAD M. , ZEROUAL F. , FALEK M.
Published: May 2012

In this paper, we propose to solve the relativistic Klein–Gordon and Dirac equations subjected to the action of a uniform electromagnetic field with a generalized uncertainty principle in the momentum space. In both cases, the energy eigenvalues and their corresponding eigenfunctions are obtained. The limit case is then deduced for a small parameter of deformation.
DARK MATTER EFFECTIVE THEORY
Authors: DEL NOBILE EUGENIO , SANNINO FRANCESCO
Published: May 2012

We organize the effective (self-)interaction terms for complex scalar dark matter candidates which are either an isosinglet, isodoublet or an isotriplet with respect to the weak interactions. The classification has been performed ordering the operators in inverse powers of the dark matter (DM) cutoff scale. We assume Lorentz invariance, color and charge neutrality. We also introduce potentially interesting DM induced flavor-changing operators. Our general framework allows for model independent investigations of DM properties.
RENORMALIZATION OF A NONCOMMUTATIVE FIELD THEORY
Authors: GROSSE HARALD , WULKENHAAR RAIMAR
Published: May 2012

We discuss a special Euclidean [Formula: see text]-quantum field theory over quantized space–time as an example of a renormalizable field theory. Using a Ward identity, it was possible to prove the vanishing of the beta function for the coupling constant to all orders in perturbation theory. We extend this work and obtain from the Schwinger–Dyson equation a nonlinear integral equation for the renormalized two-point function alone. The nontrivial renormalized four-point function fulfills a linear integral equation with the inhomogeneity determined by the two-point function. These integral equations might be the starting point of a nonperturbative construction of a Euclidean quantum field theory on a noncommutative space. We expect to learn about renormalization from this almost solvable model.
GRAVITY IN CURVED PHASE-SPACES, FINSLER GEOMETRY AND TWO-TIMES PHYSICS
Authors: CASTRO CARLOS
Published: May 2012

The generalized (vacuum) field equations corresponding to gravity on curved 2d-dimensional (dim) tangent bundle/phase spaces and associated with the geometry of the (co)tangent bundle TMd-1, 1(T*Md-1, 1) of a d-dim space–time Md-1, 1 are investigated following the strict distinguished d-connection formalism of Lagrange–Finsler and Hamilton–Cartan geometry. It is found that there is no mathematical equivalence with Einstein's vacuum field equations in space–times of 2d dimensions, with two times, after a d+d Kaluza–Klein-like decomposition of the 2d-dim scalar curvature R is performed and involving the introduction of a nonlinear connection [Formula: see text]. The physical applications of the 4-dim phase space metric solutions found in this work, corresponding to the cotangent space of a 2-dim space–time, deserve further investigation. The physics of two times may be relevant in the solution to the problem of time in quantum gravity and in the explanation of dark matter. Finding nontrivial solutions of the generalized gravitational field equations corresponding to the 8-dim cotangent bundle (phase space) of the 4-dim space–time remains a challenging task.
HYBRID INCREMENTAL ALGORITHMS FOR BOOLEAN SATISFIABILITY
Authors: LETOMBE FLORIAN , MARQUES-SILVA JOAO
Published: May 2012

Boolean Satisfiability (SAT) solvers have been successfully applied to a wide range of practical applications, including hardware model checking, software model finding, equivalence checking, and planning, among many others. SAT solvers are also the building block of more sophisticated decision procedures, including Satisfiability Modulo Theory (SMT) solvers. The large number of applications of SAT yields ever more challenging problem instances, and motivate the development of more efficient algorithms. Recent work studied hybrid approaches for SAT, which involves integrating incomplete and complete SAT solvers. This paper proposes a number of improvements to hybrid SAT solvers. Experimental results demonstrate that the proposed optimizations are effective. The resulting algorithms in general perform better and, more importantly, are significantly more robust.
TRANSLATION ASSISTANCE SYSTEM BASED ON SELECTIVE WEIGHTING AND CLUSTER-BASED SEARCHING METHODS
Authors: SEON CHOONG-NYOUNG , KIM HARKSOO , SEO JUNGYUN
Published: May 2012

Visiting a foreign country is now much easier than it was in the past. This has led to a consequent increase in the need for translation services during these visits. To satisfy this need, a reliable translation assistance system based on sentence retrieval techniques is proposed. When a user inputs a sentence in his/her native language, the proposed system retrieves sentences similar to the input sentence from a pre-constructed bilingual corpus and returns pairs of sentences in the native and foreign languages. To reduce the lexical disagreement problems that inevitably occur in this sentence retrieval application, the proposed system uses multi-level linguistic information (i.e., keywords, sentence types, and concepts) with different weights as indexing terms. In addition, the proposed system uses clustering information from sentences with similar meanings to smooth the retrieval target sentences. In an experiment, the proposed system outperformed traditional IR systems. Based on various experiments, it was found that multi-level information was effective at alleviating critical lexical disagreement problems in sentence retrieval. It was also found that the proposed system was suitable for sentence retrieval applications such as translation assistance systems.
ON BIFURCATION SETS FOR SYMBOLIC DYNAMICS IN THE MILNOR–THURSTON WORLD
Authors: LABARCA R. , MOREIRA C. , PUMARIÑO A. , RODRÍGUEZ J. A.
Published: May 2012

We show the continuity of the topological entropy for the Milnor–Thurston world of interval maps and we compute the minimum and the maximum values for the entropy of a maximal sequence of any given period. We also study (fractal) geometric properties of the bifurcation set in the parameter space and in the associated phase spaces Σ[a, b], and we compare these results with the previously known results about the lexicographic world of interval maps (related to Lorenz-like maps).
TWO ALMOST HOMOCLINIC SOLUTIONS FOR SECOND-ORDER PERTURBED HAMILTONIAN SYSTEMS
Authors: JANCZEWSKA JOANNA
Published: May 2012

We prove the existence of two almost homoclinic solutions for a class of second-order perturbed Hamiltonian systems [Formula: see text], where L : ℝ → ℝn2is a continuous matrix-valued function such that L(t) is symmetric and positive definite for each t ∈ ℝ, the smallest eigenvalue of L(t) → ∞ as |t| → ∞, W : ℝ × ℝn→ ℝ is a C1-map satisfying the Ambrosetti–Rabinowitz condition and f : ℝ → ℝnis continuous and sufficiently small in L2(ℝ, ℝn). We improve a result by Rabinowitz and Tanaka [Math. Z. 206 (1991) 473–499].
LORENTZ SPACE ESTIMATES FOR THE COULOMBIAN RENORMALIZED ENERGY
Authors: SERFATY SYLVIA , TICE IAN
Published: May 2012

In this paper we obtain optimal estimates for the "currents" associated to point masses in the plane, in terms of the Coulombian renormalized energy of Sandier–Serfaty [From the Ginzburg–Landau model to vortex lattice problems, to appear in Comm. Math. Phys. (2012); One-dimensional log gases and the renormalized energy, in preparation]. To derive the estimates, we use a technique that we introduced in [Lorentz space estimates for the Ginzburg–Landau energy, J. Funct. Anal. 254(3) (2008) 773–825], which couples the "ball construction method" to estimates in the Lorentz space L2,∞.
NONLOCAL KORN-TYPE CHARACTERIZATION OF SOBOLEV VECTOR FIELDS
Authors: MENGESHA TADELE
Published: May 2012

A new nonlocal characterization of Sobolev vector fields in the spirit of Korn's inequality is obtained. As an application of this result, a nonlocal means of identification of rigid motions is given. A nonlocal characterization of vector fields with bounded deformation is also presented. A compactness criteria is proved for bounded sequences of vector fields in Lp.
ELLIPTIC CURVE POINTS AND DIOPHANTINE MODELS OF ℤ IN LARGE SUBRINGS OF NUMBER FIELDS
Authors: SHLAPENTOKH ALEXANDRA
Published: May 2012

Let K be a number field such that there exists an elliptic curve E of rank one over K. For a set [Formula: see text] of primes of K, let [Formula: see text]. Let P ∈ E(K) be a generator of E(K) modulo the torsion subgroup. Let (xn(P), yn(P)) be the affine coordinates of [n]P with respect to a fixed Weierstrass equation of E. We show that there exists a set [Formula: see text] of primes of K of natural density one such that in [Formula: see text] multiplication of indices (with respect to some fixed multiple of P) is existentially definable and therefore these indices can be used to construct a Diophantine model of ℤ. We also show that ℤ is definable over [Formula: see text] using just one universal quantifier. Both the construction of a Diophantine model using the indices and the first-order definition of ℤ can be lifted to the integral closure of [Formula: see text] in any infinite extension K∞of K as long as E(K∞) is finitely generated and of rank one.
NUMBER OF SOLUTIONS FOR QUARTIC SIMPLE THUE EQUATIONS
Authors: WAKABAYASHI ISAO
Published: May 2012

Let F(X, Y) = bX4- aX3Y - 6bX2Y2+ aXY3+ bY4∈ Z[X, Y]. We show that the number of solutions for the Thue equation F(x, y) = ±1 is 0 or 4 except for a few already known cases. To obtain an upper bound for the size of solutions, we use Padé approximation method. To obtain a lower bound for the size of solutions, we construct a continued fraction with positive or negative rational partial quotients. This construction is carried out carefully by using special properties of the form F. Combining these lower and upper bounds, we obtain the result.
RATIONAL SOLUTIONS OF POLYNOMIAL-EXPONENTIAL EQUATIONS
Authors: GÜNAYDIN AYHAN
Published: May 2012

We give a description of solutions of polynomial-exponential equations where the variables vary over rational numbers. Using this, we also prove a finiteness result.
RAMIFICATION POLYGONS, SPLITTING FIELDS, AND GALOIS GROUPS OF EISENSTEIN POLYNOMIALS
Authors: GREVE CHRISTIAN , PAULI SEBASTIAN
Published: May 2012

Let ϕ(x) be an Eisenstein polynomial of degree n over a local field and let α be a root of ϕ(x). The Newton polygon of ρ(x) = ϕ(αx+α)/αn is called the ramification polygon of ϕ(x). We attach an additional invariant, the segmental inertia degree, to each segment of the ramification polygon and use the slopes of the segments and their segmental inertia degrees to describe the splitting field of ϕ(x). Furthermore we present a method for determining the Galois group of ϕ(x) when the ramification polygon consists of one segment.
ARITHMETIC SUMS OF LIOUVILLE TYPE OVER RELATIVELY PRIME PAIRS
Authors: EL BACHRAOUI MOHAMED
Published: May 2012

We prove Liouville's type identities on sums of even integer functions ranging over sets involving relatively prime pairs.
ON THE FACTORIZATION OF THE TRINOMIALS xn + cxn-1 + d
Authors: HARRINGTON JOSHUA
Published: May 2012

In this paper we investigate the factorization of trinomials of the form xn + cxn-1 + d ∈ ℤ[x]. We then use these results about trinomials to prove results about the factorization of polynomials of the form xn + c(xn-1 +⋯+ x + 1) ∈ ℤ[x].
PERIODIC CONTINUED FRACTIONS AND JACOBI SYMBOLS
Authors: GIRSTMAIR KURT
Published: May 2012

Previously we proved the periodicity of the Jacobi symbol [Formula: see text] for the convergents pk/qk of infinite purely periodic continued fractions. The aim of this note is to establish an analogous result for mixed periodic continued fractions.
REMODELING OF THE LIVER ANDTetrahymena pyriformisMITOCHONDRIA DURING METABOLIC DEPRESSION
Authors: MOKHOVA E. N.
Published: May 2012

This review compares the functional characteristics of liver mitochondria isolated from (i) the hibernating animals and (ii) of mitochondria studied in situ in motile Tetrahymena pyriformis during stationary growth phase, washed with a substrate-free medium. To explain the considered data, a hypothesis is proposed that the prerequisite for surviving under metabolic depression is a rearrangement of mitochondrial morphology to a condensed state. Such remodeling is induced either (1) by low mitochondrial electrical potential difference across the inner mitochondrial membrane for Tetrahymena, or (2) by low temperature for liver mitochondria. A special methodical part is focused on sources of errors and selection of suitable methods during metabolic depression investigation.
Tunnel valleys: current knowledge and future perspectives
Authors: van der Vegt P. , Janszen A. , Moscariello A.
Published: May 2012

Tunnel valleys are elongated incisions that are commonly interpreted as being the result of erosional processes by subglacial meltwater occurring under continental ice sheets. The abundance, size and the primarily coarse-grained infill of these features have made tunnel valleys important hydrocarbon and groundwater reservoirs. Although numerous tunnel valleys have been described over the last century, their formation and infill remain poorly understood. This review summarizes and discusses the current knowledge of tunnel valleys, providing an overview of the observations around the world. Morphological aspects that separate tunnel valleys from other landforms are discussed, as well as the wide variety of sedimentary environments found to contribute to the infilling of these features. The depth of the incision and the character of ice retreat significantly determine the final infill architecture. The formational hypotheses proposed in the literature are assessed to test their wider applicability to all other tunnel valleys in order to find a generic model that helps in the prediction of the morphology and infilling of both Pleistocene and pre-Pleistocene age. A quasi-steady-state model, with small meltwater outbursts that erode tunnel valleys near the ice margin, seems compatible with most of the known valleys. Other proposed models require specific geographical or climatic conditions.
Immuno - (Aptamers) Nano-Modified Multi - Arrays Biosensors
Authors: Braustein Harold E.
Published: May 2012

The stupendous enhance in the field of biosensors development was observed in recent years with promising applications in an eclectic range of disciplines, including medical analysis, food and the environment. Escalating number of analytes requiring monitoring and others that require control, and the ought for high sensitivity, speed, and accuracy of analytical measurements have enthused considerable interest in developing sensors as diagnostics tools. Assortment of molecules with biorecognition powers are available naturally such as antibodies, enzymes, cell receptors and nucleic acids and are used as the sensing receptors in biosensors. The eclectic range of transducers is also feasible to fulfill the rapid monitoring needs of the diagnostic market. Immuno-Biosensors can also be integrated into user-friendly instruments as an on-line monitoring device or a unique sensor. This paper deals with recent developments in biosensors in The Biosensor Laboratory at Tel Aviv University and their potential use in the environmental health and medical diagnostic market.
Conductance and Flux Measurements on Capillary-Incorporated Nanoporous Monoliths Derived from a Polystyrene-Poly(Methylmethacrylate) Block Copolymer
Authors: Ibrahim Shaida , Nagasaka Shinobu , Moore David S. , Higgins Daniel A. , Ito Takashi
Published: May 2012

This paper reports ionic conductance and molecular flux measurements for characterizing microcapillary-incorporated nanoporous monoliths derived from a cylinder-forming polystyrene-poly(methylmethacrylate) diblock copolymer. Such monoliths were fabricated by introducing molten polymer into the end of quartz microcapillaries, followed by UV irradiation and acetic acid treatment. The ionic conductance across the monoliths in 1:1 electrolyte solution decreased with decreasing electrolyte concentration from 0.10 M to 1.0 mM, reflecting bulk ionic conductance. In contrast, it became constant at concentrations ≤ 0.10 mM, governed by surface conductance determined by the cation surface mobility and the surface charge density of the negatively-charged nanopores. Although the conductance data and scanning electron microscopy images indicated the presence of monolith cracks with sizes significantly larger than the expected nanopore size (10 nm in radius), observation of the permselective exclusion of anionic sulforhodamine B from the negatively charged nanopores indicated that the solvated species were mainly transported through nanoscale pathways.
Electrochemistry in Nano-Space of Structurally Controlled Carbon Materials
Authors: Hayashi Akari , Yagi Ichizo , Kimijima Ken'ichi , Sasaki Kazunari
Published: May 2012

For the purpose of studying electrochemical reactions in nano-space of structurally controlled carbon, electrochemistry inside the hydrophobic 8 nm pores with platinum deposited mesoporous carbon (Pt/MC) was investigated, and reaction selectivity within carbon nano-space was demonstrated. Distinctive activities toward hydrogen evolution/oxidation and oxygen evolution reactions were observed, comparing to reactions in larger pores (>30 nm). Only small amount of water is expected to exist within such small nano-space even though a proton pass is effectively maintained. Consequently, selectivity in reactions, such as activation of proton-related reactions and suppression of water-related reactions, is achieved by Pt/MC electrocalatysts.
Capital Cost Sensitivity Analysis of an All-Vanadium Redox-Flow Battery
Authors: Moore Mark , Watson Jack , Zawodzinski Thomas A. , Zhang Mengqi , Counce Robert M.
Published: May 2012

Interest in the development of redox-flow batteries (RFBs) for large-scale grid storage is growing, and considerable investments have been made into the research and development of RFBs over the past few decades. Unfortunately, practical implementation has been hampered by various cost and performance issues typical of an immature state of development. One critical factor for the competitiveness of this technology is the installed cost. In this work, we incorporate recent developments in all-vanadium RFBs research and present an analysis of the associated cost factors. The major components of a RFB that affect installed cost are identified and used as variables to create a capital cost function. The function is then used to calculate the rate of change of the capital costs with respect to the major components. The capital costs are also calculated for a range of component values and plotted. Key findings include a high sensitivity of system capital cost to purity of vanadium and substantial fractions of the cost associated with perflurorosulfonic acid membranes currently used for proton transport.
Ta Compound Film as New Anode Material for Polymer Electrolyte Water Electrolysis
Authors: Yamauchi Kyosuke , Matsuzawa Koichi , Ota Ken-ichiro , Mitsushima Shigenori
Published: May 2012

In order to attempt Ta compounds as anode electrocatalyst for Polymer electrolyte water electrolysis, the catalytic activities of Ta compound films for the oxygen evolution reaction (OER) was investigated. Ta compound films were prepared under several partial pressures of nitrogen and oxygen at several temperatures by reactive sputtering. Although Ta compound films had high overpotential for the OER, the catalytic activities of Ta compounds for the OER were changed by the change of preparation condition.
Interactions between Organics and Microorganisms in the Electrochemical Disinfection Using a Boron-Doped Diamond Anode
Authors: Li Hongna , Ni Jinren
Published: May 2012

The efficiency of water disinfection and organics degradation were simultaneously investigated in an electrochemical cell using a boron-doped diamond anode. Commonly existing pollutants were selected as the representative organics: phenol, resorcinol, m-trihydroxybenzene, dimethyl phthalate and diethyl phthalate. Escherichia coli was used as the indicator microorganism. Electrolysis in 0.2 M Na2SO4 was conducted with organics only, microorganisms only, and both organics and microorganisms. In the coexisting process, E. coli inactivation slowed, while organic removal became a little faster compared with the condition with each alone. The coexisting system without electrolysis showed that there was adsorption interaction between organic molecules and the microorganisms, which was strengthened under an electric field and thus facilitated the degradation of organics. The influences of organic concentration, pH, and humic acid were studied. The intermediates of the five organics were detected by GC/MS with/without microorganisms and showed no difference.
Recent Advances in Cell Cost and Efficiency for PEM-Based Water
Electrolysis
Authors: Ayers Katherine E. , Capuano Christopher , Anderson Everett B.
Published: May 2012

Water electrolysis using proton exchange membrane (PEM) technology is a promising pathway
to generate hydrogen for energy applications because of the lack of corrosive
electrolytes, small footprint, and ability to generate at differential pressure, requiring
only deionized water and an energy source. Using a renewable energy source as the input
power enables a carbon-free cycle. In 2008, Proton created a cell stack roadmap to
leverage the material advancements made in fuel cells as well as address new design
requirements. The overall impact of this research to date has been considerable.
Efficiency improvements of 20% have been demonstrated for membrane and catalyst
configurations that have been tested to over 1000 hours. Cost reductions of over 15% of
the total stack cost have also been proven to be feasible. Additional pathways for the
next 3-5 years are expected to continue to make progress in reducing the cost of hydrogen
from water electrolysis.
Beneficial Use of a Virtual Reference Electrode for the Determination of SOC Dependent Half Cell Potentials
Authors: Schmidt Jan Philipp , Richter Jan , Klotz Dino , Ivers-Tiffée Ellen
Published: May 2012

A method is presented which obtains the half cell potentials of a sealed commercial cell from a measured OCV-curve. The underlying model is introduced and the physical interpretable parameters are discussed. The method is validated by two experiments simulating different aging mechanisms and future potentials are discussed.
Effect of Transport on the Performance of a Hydrogen-Bromine Flow Battery
Authors: Nguyen Trung V. , Kreutzer Haley
Published: May 2012

Renewable energy sources including wind and solar can supply a significant amount of electrical energy around the world. However, because of their intermittent nature the potential of these two energy sources can be fully exploited only if a suitable energy storage system is provided. Considering the requirements of energy capacity, efficiency and cost of this application, the Hydrogen-Bromine flow battery has been identified as a great candidate for electrical energy storage. Its many advantages include fast reaction kinetics, high energy storage capacity, and high reliability. This paper discusses the unique features and the advantages and disadvantages of this H2-Br2 system and shows the electrochemical charge and discharge performance obtained at different concentrations and flow rates. A comparison of the H2-Br2 to the H2-O2 system is also included to highlight the fast kinetics of the bromine reactions. Finally, test results are also included to show that flow field design like the interdigitated flow field can be used to reduce the effect of transport limitation at the bromine electrode.
Dry Polymer/Sulfur-Based Ionic Liquid Hybrid Electrolytes for Lithium Batteries
Authors: Fisher Aaron , Khalid Mian B. , Kofinas Peter
Published: May 2012

Flexible, solid polymer electrolytes based upon high molecular weight poly(ethylene oxide) incorporating triethyl sulfonium bis(trifluoro sulfonyl) imide have demonstrated lithium conductivity at physiological temperatures. Cycling tests on a Li/electrolyte/ LiFePO4 have been conducted showing stability for the charge and discharge capacity after the initial decay. Slipping has been observed, whereby the charge and discharge capacity are continuously mismatched by a constant amount over extended cycling. Work is underway to perfect the cell set-up as intra-electrode diffusion kinetics dominates the observed phenomena.
Metal-Semiconductor-Metal Directly Illuminated Electron Detector and Secondary Electron Detector with Metal Nano-Rod Array and Trench Structure to Enhance the Performance
Authors: Lee Ming-Lun , Ho Kung-Chu , Kuan Chieh-Hsiung
Published: May 2012

In this work, we first fabricated the conventional metal-semiconductor-metal (MSM) interdigitated electron detector with aluminum contact as the control group, then used e-beam lithography system and reactive ion etcher (RIE) to fabricate aluminum nano-rod array structure on the contact area and used RIE to fabricate the periodic rectangle trench in the active area of the electron detector as another MSM interdigitated electron detector at the same time as the experimental group. According to the experimental data, we found that the MSM electron detectors with aluminum nano-rod array and periodic trench structure had better electricity characteristic and performance as directly illuminated and secondary electron detector.
Partial State-of-Charge Duty: A Challenge but Not a Show-Stopper for Lead-Acid Batteries!
Authors: Moseley Patrick T. , Rand David A.
Published: May 2012

The mechanism by which conventional lead-acid batteries (both flooded and valve-regulated designs) fail when subjected to high-rate partial-state-of-charge (HRPSoC) operation in hybrid electric vehicles is manifested as poor dynamic charge acceptance at the negative plate. This parameter is defined as the amount of charge that is actually delivered to the battery during regenerative braking phases of a driving cycle, divided by the amount of charge that could have been provided by the generator. The possible reasons for this mode of failure are discussed in terms of the processes that support the charge reaction and the competing secondary reactions that can take place at the plate during charge, namely: oxygen reduction (for valve-regulated designs), hydrogen evolution, and the accumulation of capacitive charge. To reach a full understanding of the processes associated with the unusual duty of HRPSoC operation, it is necessary: (i) to examine aspects of the charge reaction that, to date, have received little attention, e.g., local reaction within the pores of the plate active-material, effects of acid concentration on the local solubility of lead sulfate, non-uniformity of potential across the plate; (ii) to evaluate the beneficial effects to be gained from the respective use of carbon, modifications of grid design (twin tab), and the UltraBatteryTM concept.
Simulation of SLI Lead-Acid Batteries for SoC, Aging and Cranking Capability Prediction in Automotive Applications
Authors: Pilatowicz Grzegorz , Budde-Meiwes Heide , Schulte Dominik , Kowal Julia , Sauer Dirk Uwe , Zhang Yilu , Tong Niannian , Salman Mutasim , Gonzales Dennis , Alden Jeff
Published: May 2012

SLI lead-acid batteries are still the most commonly used technology in automotive applications around the world. Despite its relatively low gravimetric and volumetric energy density in comparison with other battery solutions it is still installed in the newest micro-hybrid and conventional cars due to its low cost. To facilitate the design of multi-physical systems as complex as modern automobiles, it is critical to have a precise battery aging model that incorporates various operation conditions. This paper presents an aging model that provides crucial information about state of health of SLI battery during lifetime for any conditions like climate, driving style, charging strategy or different battery management approaches. Described model is based both on empirical and physico-chemical solutions and can be calibrated to simulate any SLI lead-acid battery without design limitations.
Lead-Carbon Electrode with Inhibitor of PbSO4 Recrystallization in Lead-Acid Batteries Operating on HRPSoC Duty
Authors: Pavlov Detchko , Nikolov Plamen
Published: May 2012

The major problem of lead-acid batteries for application in hybrid electric vehicles (HEV) is the progressive sulfation of the negative plates as a result of incomplete charge of the cells in the HEV mode of operation. Under these conditions, recrystallization processes take place whereby big PbSO4 crystals grow at the expense of dissolution of smaller ones. The present study has established experimentally that addition of poly-aspartic acid to the solution or to the negative paste retards significantly the crystal growth of lead sulfate crystals. Small PbSO4 crystals are highly soluble and sustain high concentration of Pb2+ ions in the solution, thus improving the charge acceptance of the cells. It has also been established that poly-aspartic acid increases the overpotential of hydrogen evolution on the lead electrode. Linear sweep voltammetry experiments and cycling tests of cells under simulated high-rate partial-state-of-charge conditions have confirmed the above effects of poly-aspartic acid.
A 12 V Substrate-Integrated PbO2-Activated Carbon Asymmetric Hybrid Ultracapacitor with Silica-Gel-Based Inorganic-Polymer Electrolyte
Authors: Banerjee Anjan , Ravikumar Musuwathi K. , Jalajakshi Amulur , Gaffoor Shaik A. , Shukla Ashok K.
Published: May 2012

A 12 V Substrate-Integrated PbO2-Activated Carbon hybrid ultracapacitor (SI-PbO2-AC HUCs) with silica-gel sulfuric acid electrolyte is developed and performance tested. The performance of the silica-gel based hybrid ultracapacitor is compared with flooded and AGM-based HUCs. These HUCs comprise substrate-integrated PbO2 (SI-PbO2) as positive electrodes and high surface-area activated carbon with dense graphite-sheet substrate as negative electrodes. 12 V SI-PbO2-AC HUCs with flooded, AGM and gel electrolytes are found to have capacitance values of 308 F, 184 F, and 269 F at C-rate and can be pulse charged and discharged for 100,000 cycles with only a nominal decrease in their capacitance values. The best performance is exhibited by gel-electrolyte HUCs.
Corrosiveness of Different Treated Municipal Wastewaters Used as Power Plant Cooling System Makeup Water: A Bench-Scale Evaluation
Authors: Choudhury Mahbuboor R. , Hsieh Ming-Kai , Vidic Radisav D. , Dzombak David A.
Published: May 2012

Corrosion of metals and metal alloys in a recirculating power plant cooling system is a major operational concern and is exacerbated when using treated municipal wastewater as makeup water, due to the degraded water quality. In this study different treated municipal wastewaters were used in a bench-scale water recirculation system, simulating cooling water conditions in power plant cooling systems. The treated municipal wastewaters used were: secondary treated municipal wastewater (SMW) with pH reduction, SMW with nitrification-filtration, and SMW with nitrification-filtration-granular activated carbon (GAC) adsorbtion. The corrosiveness of these treated municipal wastewaters to mild steel, copper and cupronickel alloys were analyzed. The efficacy of Tolyltriazole (a corrosion inhibitor) was also analyzed in this study. Results showed tolyltriazole successfully reduced the corrosion rates of mild-steel copper and cupronickel alloys in all the systems.
Surface and Electrochemical Behavior of HSLA Steel in Supercritical CO2-H2O Environment
Authors: Ziomek-Moroz Margaret , Holcomb Gordon R. , Tylczak Joesph , Beck Justin , Fedkin Mark , Lvov Serguei
Published: May 2012

General corrosion was observed on high strength low alloy carbon steel after electrochemical impedance spectroscopy experiments (EIS) performed in H2O saturated with CO2 at 50 °C and 15.2 MPa. However, general and localized were observed on the same material surfaces after the EIS experiments performed in supercritical CO2 containing approximately 6100 ppmv H2O at 50 °C and 15.2 MPa. The general corrosion areas were uniformly covered by the FeCO3-like phase identified by X-ray diffraction (XRD). In the area of localized corrosion, XRD also revealed FeCO3-rich islands embedded in α-iron. The energy dispersive X-ray (EDX) analysis revealed high concentrations of iron, carbon, and oxygen in the area affected by general corrosion and in the islands formed in the area of localized corrosion. The real and imaginary impedances were lower in H2O saturated with CO2 than those in the supercritical CO2 containing the aqueous phase indicating faster corrosion kinetics in the former.
Study on the Corrosion Behavior of Reinforcing Steel by Electrochemical Techniques and XPS
Authors: Zhu Yan-Feng , Du Rong-Gui , Chen Wen , Hu Rong-Gang , Shi Hai-Yan , Guo Ya , Wang Xiao-Ping , Lin Chang-Jian
Published: May 2012

Reinforcing steel in concrete is protected from corrosion due to the formation of a passive film on its surface. The steel passivity depends on the physical and chemical conditions in its environment. In this work, the effect of pH values, Cl- concentrations on the corrosion behavior of reinforcing steel in the simulated concrete pore solutions have been studied by electrochemical techniques and X-ray photoelectron spectroscopy. The results indicated that the corrosion potential of the steel shifted negatively and its corrosion current density rose with the Cl- concentration increasing and pH decreasing in the solution. The passive film of the steel was mainly composed of Fe-oxides. When the Cl concentration reached 0.6 M or pH decreased to 11.3, the steel passivity was destroyed, the Fe2+ atomic percentage of the steel surface film increased and the Fe3+ content decreased.
Investigation of the Electrochemical Behaviour of MWCNTs in the Detection of Cr(VI)
Authors: Garry Lynn M. , Alcock Bernadette E. , Breslin Carmel B.
Published: May 2012

The electrochemical behaviour of a glassy carbon (GC) electrode modified with multi-walled carbon nanotubes (MWCNTs) was investigated and characterised using K3[Fe(CN)6] as a probe. An increase in the electroactive surface area and the rate of electron transfer was observed on sonication of the MWCNTs prior to casting on the GC electrode. The modified electrode was also used in the detection of Cr (VI) in both pH 5.0 and pH 2.0 aqueous solutions. Better detection limits were obtained in the acidic solution.
Electrocatalytic Oxidation of NADH Using Alizarin Immobilized Carbon Nanotube Modified Electrode
Authors: Puchakayala Swetha , Annamalai Senthil Kumar
Published: May 2012

Electrocatalytic oxidation of NADH has been demonstrated using an electrochemically immobilized Alizarin (AZ) on multiwalled carbon nanotube (MWCNT) modified glassy carbon electrode (GCE/AZ@MWCNT) in pH 7 phosphate buffer solution. The GCE/AZ@MWCNT shows three surface-confined redox peaks centered (E1/2) at -0.067, -0.351 and -0.620 V vs Ag/AgCl, due to the 1,2 dihydroxy and anthraquinone (at two different energetic MWCNT) redox sites of the AZ. Calculated respective surface excess values are 59.13, 8.12 and 9.73'10-10 mol.cm-2 . Amongst the three, the E1/2 = -0.067 redox peak shows specific NADH electrocatalytic oxidation behavior in a concentration range = 0−7 mM by cyclic voltammetry. Transmission electron microscope characterization reveals immobilization of the AZ both on inner and outer walls of the MWCNT. Investigation on different CNTs viz., impure, purified, functionalized MWCNT, and single-walled carbon nanotube systems, the impure MWCNT shows the highest AZ immobilization and electrocatalytic behavior towards NADH oxidation.
Bandgap Narrowing of Zinc Oxide (ZnO) by Nitrogen Incorporation for Solar Driven Hydrogen Production
Authors: Shet Sudhakar
Published: May 2012

In this study, report on the synthesis of ZnO:N thin films by reactive RF magnetron sputtering using a Zn metal target & ZnO target in mixed N2 and O2 ambient. We found that the N concentration in ZnO:N thin films can be effectively controlled by varying the RF power. ZnO:N films with narrowed bandgaps were synthesized. The photoelectrochemical properties of nitrogen-incorporated ZnO (ZnO:N) films were measured and compared with those of pure ZnO films. We find that nitrogen incorporation narrows the bandgap of ZnO and shifts the optical absorption into the visible-light regions. We further find that the ZnO:N films provide considerable photoresponse in the long-wavelength regions. As a result, the ZnO:N films exhibit higher photocurrents than pure ZnO films.
Simulating Electrode-Solution Interfaces Using 3D Cellular Automation
Authors: Zhang Yingrui , Quesnel David J.
Published: May 2012

A three-dimensional cellular automation model is applied to study the spatial distribution of water molecules contacting a structureless planar electrode. Water molecules occupying each cell are modeled as electric dipoles comprising separated positive and negative charges. Electrostatic interactions between cells are computed to determine local torques on water dipoles. Meanwhile, the dipole rotational response is modeled as a thermally activated event. Interfacial phenomena, such as the parallel alignment of water molecules to a neutral planar electrode emerge spontaneously from the simulation. When solvated ions are available in the water, attraction and repulsion due to charges cause a non-uniform distribution of anions and cations. The simulation results presented here, including the computed distribution profiles for anions and cations influenced by the electrode charge density, the resulting electric fields, and the variation of the dielectric constant of water, are consistent with theoretical calculations and existing simulations based on molecular dynamics.