bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase formation and electrical properties of the LaCoO3 obtained by water-based sol-gel method with citric acid
Authors: Predoana Luminita , Malic Barbara , Kosec Marija , Scurtu Mariana , Caldararu Monica , Zaharescu Maria
Published: January 2013

In the present work the LaCoO3 formation from gel precursors obtained by water-based sol-gel method with citric acid was studied. As precursors La and Co nitrates were used. The obtained gels were analyzed by TG/ DTA and TG/EGA. The decomposition of the gels takes place in two main steps with the evolution of the same volatile compounds (H2O, CO2 and NO2) leading to the conclusion that two types of bonding of the components in the gels occurred. The decomposition of the gels takes place up to 400?C. The gels thermally treated at 600?C lead to single pure perovskite rhombohedral phase of lanthanum cobalt oxide (LaCoO3). Some electrical properties of LaCoO3 measured in 'operando' conditions, i.e. in gas flow, at atmospheric pressure (by using the differential step technique DST) are presented and discussed.
Al-doped and undoped zinc oxide films obtained by soft chemistry
Authors: Mihaiu Suzana , Toader Alexandra , Anastasescu Mihai , Gabor Mihai , Petrisor Traian , Stoica Mihai , Zaharescu Maria
Published: January 2013

Zinc oxide with a hexagonal wurzite type structure is an unique material that exhibits semiconducting, piezoelectric and pyroelectric properties. These properties play a key role for applications in optoelectronic devices. In the present work Al-doped and undoped ZnO films were obtained by soft chemistry starting with zinc acetate dihydrate and Al(III) isopropoxide in absolute ethyl alcohol. Trietanolamine was used as chelating agent. The films were deposited by dip coating technique on the silicon substrate and thermally treated at 500?C for one hour. The morphological characteristics of the films were investigated by Atomic Force Microscopy (AFM). Optical constants, such as refractive index (n) and extinction coefficient (k), were established by Spectroellipsometry measurements. Electrical conductivity of the studied films was determined in the 20-500?C temperature range by 'the four point method'. The morphology of the films is influenced by the starting sol composition, as found from AFM. According to the ellipsometric spectral data, more porous and thinner films, with smaller refractive index were obtained in the case of Al-doped ZnO films as compared with ZnO films. Both ZnO and Al-doped ZnO films presented high electrical receptivity. .
Chemical segregation and self polarisation in ferroelectrics
Authors: Watts Bernard
Published: January 2013

Chemical partitioning or segregation is commonly encountered in solid-state syntheses. It is driven by compositional, thermal and electric field gradients. These phenomena can be quite extreme in thin films and lead to notable effects on the electrical properties of ferroelectrics. The segregation in ferroelectric thin films will be illustrated and the mechanisms explained in terms of diffusion processes driven by a potential gradient of the oxygen. The hypothesis can also explain self polarisation and imprint in ferroelectric hysteresis. .
Hyperthermic effect of magnetic nanoparticles under electromagnetic field
Authors: Baldi Giovanni , Lorenzi Giada , Ravagli Costanza
Published: January 2013

Magnetic nanoparticles have attracted increasingly attention due to their potential applications in many industrial fields, even extending their use in biomedical applications. In the latter contest the main features of magnetic nanoparticles are the possibility to be driven by external magnetic fields, the ability to pass through capillaries without occluding them and to absorb and convert electromagnetic radiation in to heat (Magnetic Fluid Hyperthermia). The main challenges of the current works on hyperthermia deal with the achievement of highly efficiency magnetic nanoparticles, the surface grafting with ligands able to facilitate their specific internalisation in tumour cells and the design of stealth nanocomposites able to circulate in the blood compartment for a long time. This article presents the synthesis of cobalt ferrite nanoparticles dispersed in diethylene glycol via the so called polyol strategy and the crystal size control through successive synthesis steps. Preliminary heat dissipation evaluations on the prepared samples were carried out and the question of how particles sizes affect their magnetic and hyperthermic properties was addressed as well. Furthermore we will present how surface chemistry can be modified in order to change the dispersity of the product without affecting magnetic and hyperthermic properties. .
SPM studies of ferroelectric nanostructures prepared by a microemulsion-assisted method onto substrates
Authors: Torres Maria , Calzada Lourdes , Rodriguez Brian , Alexe Marin , Pardo Lorena
Published: January 2013

Ferroelectric PbTiO3 nanostructures have been fabricated using two different procedures that involve microemulsions and Chemical Solution Deposition onto Pt/TiO2/SiO2/(100)Si substrates. The first procedure enables the fabrication of structures with controlled size and shape, as observed by Atomic Force Microscopy (AFM) topography and computer assisted quantitative analysis, while the second procedure, in addition, yields very small (? 20 nm) isolated, ferroelectric nanoislands. The ferroelectric character of the nanostructures is demonstrated using Piezoelectric Force Microscopy (PFM). The ferroelectric properties depend on the height of the nanostructures, showing a strong pinning layer effect for the smaller ones, revealed by the asymmetry of the piezoelectric hysteresis loops. .
Structure evolution and properties of biogenic hydroxyapatite-based biocomposite
Authors: Sych Olena , Pinchuk Nataliya , Ivanchenko Liana
Published: January 2013

Two-step sintering has been used to investigate the structure evolution and properties of the biogenic HA/glass composite containing 50 wt.% Na2O-B2O3-SiO2-based glass. The borosilicate glass facilitated the sintering process due to the viscous glass flow and stabilized the HA phase against thermal decomposition. It has been established that the structure significantly changes, becoming more homogeneous and fine-porous, in going from the charge to two-step sintered biogenic HA/glass composite in comparison with the normal sintering. The composite samples underwent significant deformation and macropore formation (0.05-2 mm) after normal sintering at 1000?C. After two-step sintering pore minimization down to 50-100 ?m occurred. The volume changes achieved 10 %. It was found that general porosity reached 15.5 %, open porosity - 74 %, compression strength - 219 MPa and composite solubility - 0.175 % mass loss after two-day soaking in physiological solution. .
Effect of synthesis route on the microstructure of SiO2 doped bismuth titanate ceramics
Authors: Kashchieva Elena , Krapchanska Milena , Slavov Stanislav , Dimitriev Yanko
Published: January 2013

Synthesis and characterization of SiO2 doped bismuth titanate ceramics were investigated. Four investigated compositions belonging to the system Bi2O3-TiO2-SiO2 are located in the section Bi4Ti3O12-SiO2, near by it and in the binary Bi2O3-TiO2 system. Melt quenching was applied for synthesis of SiO2 doped bismuth titanate ceramics and for the sample 40Bi2O3?60TiO2. The binary sample 70Bi2O3?30TiO2 is prepared by gradient heating of bulk materials near the liquidus temperature (modified solid state reaction). The influence of the thermal treatment on the phase formation and microstructure was evaluated using XRD, EDS and SEM. The binary samples prepared by solid state reaction at low temperature (1000?C) possess poly-phased dense microstructure, while secondary crystallization combined with porosity formation is typical for the sample obtained at high temperature (1150?C). The ternary Bi2O3-TiO2-SiO2 samples, obtained by supercooling of the melts down to room temperature, are thermally treated at 700, 800?C. They consist of elongated crystals in amorphous matrix. The crystals have lower Bi2O3-content and higher TiO2-content than the nominal batch composition. The XRD data show that the main crystalline phases in the ceramics produced by melt quenching method and solid state reaction are ?-Bi2O3, Bi4Ti3O12 and one unknown new phase. It is proved that the applied methods of synthesis are suitable for generation of different microstructures in the bulk SiO2 doped bismuth titanate ceramics, which is promising basis for modification of their electrical properties. .
Fast synthesis of the polycrystalline materials on the base of Zn3V2MoO11 and Zn2.5 VMoO8
Authors: Markova-Velichkova Maya , Iordanova Reni
Published: January 2013

In our study we applied two different techniques for the preparation of Zn3V2MoO11 and Zn2.5 VMoO8 polycrystalline materials - melt quenching method (up-bottom) and mechanochemical synthesis (bottom- up). These compounds belong to the family of materials with general formula M2.5VMoO8 (M=Zn, Mg, Mn, Co). They are potential candidates as catalysts in processes of selective oxidation of hydrocarbons. Until now, these two compounds were obtained by conventional solid state reaction. Using infrared spectroscopy and X-ray diffraction we proved that the melt quenching technique is a quite appropriate method for the synthesis of bulk Zn3V2-MoO11 phase. Mechanochemical activation is more appropriated for the preparation of nonosized Zn2.5VMoO8 powder. It was established that the melt quenching technique and mechanochemical activation are faster in comparison with conventional ceramic methods for the given synthesis. .
Characterization of rare-earth doped Si3N4/SiC micro/nanocomposites
Authors: Tatarko Peter , Lojanová Stefánia , Dusza Ján , Sajgalík Pavol
Published: January 2013

Influence of various rare-earth oxide additives (La2O3, Nd2O3, Sm2O3, Y2O3, Yb2O3 and Lu2O3) on the mechanical properties of hot-pressed silicon nitride and silicon nitride/silicon carbide micro/nano-composites has been investigated. The bimodal character of microstructures was observed in all studied materials where elongated ?-Si3N4 grains were embedded in the matrix of much finer Si3N4 grains. The fracture toughness values increased with decreasing ionic radius of rare-earth elements. The fracture toughness of composites was always lower than that of monoliths due to their finer Si3N4/SiC microstructures. Similarly, the hardness and bending strength values increased with decreasing ionic radius of rare-earth elements either in monoliths or composites. On the other hand, the positive influence of finer microstructure of the composites on strength was not observed due to the present defects in the form of SiC clusters and non-reacted carbon zones. Wear resistance at room temperature also increased with decreasing ionic radius of rare-earth element. Significantly improved creep resistance was observed in case either of composite materials or materials with smaller radius of RE3+. .
Ferroelectric perovskite nanopowders obtained by mechanochemical synthesis
Authors: Szafraniak-Wiza Izabela , Hilczer Bozena , Talik Ewa , Pietraszko Adam , Malic Barbara
Published: January 2013

Simple perovskite nanopowders were fabricated by mechanochemical synthesis. High-energy milling process of respective oxides, leading to production of ferroelectric perovskites, was carefully investigated and characterized by X-ray diffraction, electron microscopy and X-ray excited photoelectron spectroscopy. It has been found that: (i) the powder consists of loosely packed grains with a broad distribution of sizes between a few nm and 45 nm, (ii) the grains possess core/shell structure, (iii) the grain core of sizes larger than about 20 nm exhibits well developed crystalline structure, (iv) the grains are coated by structurally disordered (amorphous) shell. Intermediate phases have been found in the process of PbTiO3 mechanosynthesis only. The obtained nanopowders were used for preparation of dense ceramics.
Solution based approaches for the morphology control of BaTiO3 particulates
Authors: Maxim Florentina , Ferreira Paula , Vilarinho Paula , Reaney Ian , Aimable Anne , Bowen Paul
Published: January 2013

Within the action COST 539 - ELENA our contribution was aimed at studying solution based approaches for the morphology control of BaTiO3 particulates. Initially, our kinetic analysis and systematic structural and morphological studies, demonstrated that during hydrothermal synthesis from layered titanate nanotubes (TiNTS), BaTiO3 forms via two mechanisms depending on the temperature and time. At low temperatures (90?C), 'wild' type BaTiO3 dendritic particles with cubic structure were formed through a phase boundary topotactic reaction. At higher temperatures and/or for longer times time, the reaction is controlled by a dissolution precipitation mechanism and 'seaweed' type BaTiO3 dendrites are formed. Our results unambiguously elucidated why TiNTs do not routinely act as templates for the formation of 1D BaTiO3. In our subsequent investigations, the effect of additives on the aqueous and hydrothermal synthesis of BaTiO3 was assessed. We reported that although the tested additives influenced the growth of BaTiO3, their behaviour varied; poly(acrylic acid) (PAA) adsorbed on specific crystallographic faces changing the growth kinetics and inducing the oriented attachment of the particles; poly(vinyl pyrrolidone) (PVP), sodium dodecylsulfate (SDS) and hydroxypropylmethylcellulose (HPMC) act as growth inhibitors rather than crystal habit modifiers; and DFructose appeared to increase the activation energy for nucleation, resulting in small crystals (26 nm). Our work clearly indicates that the synthesis of 1D nanostructures of complex oxides by chemical methods is non trivial.
Aerosol route in processing of nanostructured phosphor materials
Authors: Marinkovic Katarina , Gomez Luz , Rabanal Maria , Mancic Lidija , Milosevic Olivera
Published: January 2013

Among the methods currently used for nanophase processing, synthesis through dispersion phase (aerosol) enables generation of ultrafine powders with controlled stoichiometry. It represents a 'bottom-up' chemical approach that provides control over a variety of important parameters enabling the formation of either amorphous, nanocrystalline or metastable phases. Particularly, the opportunities of the hot wall aerosol synthesis, i.e. spray pyrolysis, for the generation of ultrafine phosphor particles with uniformly distributed components, nano-clustered inner structure and luminescence properties is demonstrated in following systems: Gd2O3:Eu, Y2O3:Eu, (Y1-xGdx):Eu and Y3Al5O12:Ce, highlighting the research activities in the Institute of Technical Sciences of SASA, Serbia and the University Carlos III, Madrid, Spain in the framework of COST 539 Action.
Mechanically clamped PZT ceramics investigated by First-Order Reversal Curves diagram
Authors: Stoleriu Laurentiu , Ciomaga Cristina , Fochi Fabio , Ochoa Pilar , Fernández José , Galassi Carmen , Buscaglia Vincenzo , Nanni Paolo , Mitoseriu Liliana
Published: January 2013

The First Order Reversal Curves (FORC) diagrams method was developed for characterizing the switching properties of ferroelectrics. In the present paper, the FORC method was applied for hard Pb(Zr,Ti)O3 ceramics with symmetric and asymmetric clamping. An ideal high-oriented single-crystalline ferroelectric with rectangular P(E) loop would be characterised by a delta-function FORC distribution, while real ferroelectrics and mostly the polycrystalline ceramics show dispersed FORC distributions. All the investigated ceramics show FORC distributions with non-Gaussian shape, slightly elongated along the coercitive axis, meaning a high dispersion of the energy barriers separating the two bi-stable polarizations ?P. The degree of dispersion is enhanced by clamping. The maximum FORC coercivity is located at ~ (1.9-2) MV/m for all the hard ceramics. The FORC cycling experiment causes the reversal of the initial poling and result in a positive/negative bias on the FORC diagrams. According to the observed features, it results that FORC coercivity is more related to the nature of the material, while the bias field is more sensitive to the electrical and mechanical boundary conditions in which the ferroelectric ceramics evolves while switching.
Structure and composition of soils
Authors: Nenadovic Snezana , Nenadovic Milos , Kljajevic Ljiljana , Pavlovic Vladimir , Djordjevic Aleksandar , Matovic Branko
Published: January 2013

This paper presents a study of soils structure and composition using up to date technique, such as scanning electronic microscopy, atomic force microscopy, X-ray diffraction, X-ray fluorescence, as well as some other characterization methods. It was shown that soil particles have porous structure and dimensions in the range from several millimeters to several hundreds of nanometers and consist of different minerals such as kaolin, quartz and feldspate.
Thickness-dependent piezoelectric behaviour and dielectric properties of lanthanum modified BiFeo3 thin films
Authors: Biasotto Glenda , Moura Francisco , Foschini Cesar , Longo Elson , Varela Jose , Simões Alexandre
Published: January 2013

Bi0.85La0.15FeO3 (BLFO) thin films were deposited on Pt(111)/Ti/SiO2 /Si substrates by the soft chemical method. Films with thicknesses ranging from 140 to 280 nm were grown on platinum coated silicon substrates at 500?C for 2 hours. The X-ray diffraction analysis of BLFO films evidenced a hexagonal structure over the entire thickness range investigated. The grain size of the film changes as the number of the layers increases, indicating thickness dependence. It is found that the piezoelectric response is strongly influenced by the film thickness. It is shown that the properties of BiFeO3 thin films, such as lattice parameter, dielectric permittivity, piezoeletric coefficient etc., are functions of mis?t strains.
Modelling structure and properties of amorphous silicon boron nitride ceramics
Authors: Schön Johann , Hannemann Alexander , Sethi Guneet , Pentin Vladimirovich , Jansen Martin
Published: January 2013

Silicon boron nitride is the parent compound of a new class of high-temperature stable amorphous ceramics constituted of silicon, boron, nitrogen, and carbon, featuring a set of properties that is without precedent, and represents a prototypical random network based on chemical bonds of predominantly covalent character. In contrast to many other amorphous materials of technological interest, a-Si3B3N7 is not produced via glass formation, i.e. by quenching from a melt, the reason being that the binary components, BN and Si3N4, melt incongruently under standard conditions. Neither has it been possible to employ sintering of ?m-size powders consisting of binary nitrides BN and Si3N4. Instead, one employs the so-called sol-gel route starting from single component precursors such as TADB ((SiCl3)NH(BCl2)). In order to determine the atomic structure of this material, it has proven necessary to simulate the actual synthesis route. Many of the exciting properties of these ceramics are closely connected to the details of their amorphous structure. To clarify this structure, it is necessary to employ not only experimental probes on many length scales (X-ray, neutron- and electron scattering; complex NMR experiments; IR- and Raman scattering), but also theoretical approaches. These address the actual synthesis route to a-Si3B3N7, the structural properties, the elastic and vibrational properties, aging and coarsening behaviour, thermal conductivity and the metastable phase diagram both for a-Si3B3N7 and possible silicon boron nitride phases with compositions different from Si3N4 : BN = 1 : 3. Here, we present a short comprehensive overview over the insights gained using molecular dynamics and Monte Carlo simulations to explore the energy landscape of a-Si3B3N7, model the actual synthesis route and compute static and transport properties of a-Si3B3N7.
Synthesis and characterization of (Ba, Yb) doped ceria nanopowders
Authors: Matovic Branko , Pantic Jelena , Lukovic Jelena , Ilic Svetlana , Stankovic Nadezda , Kokunesoski Maja , Miljevic Miljana
Published: January 2013

Nanometric size (Ba, Yb) doped ceria powders with fluorite-type structure were obtained by applying selfpropagating room temperature methods. Tailored composition was: Ce0.95-xBa0.05YbxO2-? with fixed amount of Ba - 0.05 and varying Yb content 'x' from 0.05 to 0.2. Powder properties such as crystallite and particle size and lattice parameters have been studied. R?ntgen diffraction analyses (XRD) were used to characterize the samples at room temperature. Also, high temperature treatment (up to 1550?C) was used to follow stability of solid solutions. The mean diameters of the nanocrystals are determined from the full width at half maxima (FWHM) of the XRD peaks. It was found that average diameter of crystallites is less than 3 nm. Williamson- Hall plots were used to separate the effect of the size and strain in the nanocrystals.
Structure prediction and energy landscape exploration in the zinc oxide system
Authors: Zagorac Dejan , Schön Johann , Pentin Vladimirovich , Jansen Martin
Published: January 2013

The rational planning of syntheses, i.e. the search for new crystalline compounds followed by their synthesis is a central topic of solid state chemistry. In order to gain new insights in the ZnO system, we have performed global explorations of the energy landscape using simulated annealing with an empirical potential, both at standard and elevated pressure (up to 100 GPa). Besides the well-known structure types (wurtzite, sphalerite and rock-salt), many new interesting modifications were found in different regions of the energy landscape, e.g. the '5-5' type, the NiAs type, and the ?-BeO type. Furthermore, we observed many distorted variations of these main types, in particular new structures built-up from various combinations of structure elements of these types, exhibiting a variety of stacking orders.
Synthesis and characterization of carbon cryogel/zeolite composites
Authors: Babic Biljana , Kokunesoski Maja , Gulicovski Jelena , Prekajski Marija , Pantic Jelena , Radosavljevic-Mihajlovic Ana , Matovic Branko
Published: January 2013

A novel method for synthesis of carbon cryogel/zeolite composites was obtained. Method considers forming of carbon cryogel from the sol-gel polycondenzation of resorcinol and formaldehyde, followed by freeze drying, and subsequent pyrolysis in presence of different amount of zeolite. Characterization of composite materials by nitrogen adsorption shows that samples are micro- and mesoporous and that specific surface area decrease with increasing the amount of zeolite in samples. XRD method confirms amorphous structure of carbon cryogel and crystalline structure of zeolite, i.e. structure of zeolite has not been destroyed by carbonization process. SEM and EDX analyses reveal homogenous distribution of zeolite through out carbon cryogel and corresponding composition.
Mechanical and thermomechanical properties of polycarbonate-based polyurethane-silica nanocomposites
Authors: Poręba Rafał , Spírková Milena , Hrdlicka Zdeněk
Published: January 2013

In this work aliphatic polycarbonate-based polyurethane-silica nanocomposites were synthesized and characterized. The influence of the type and of the concentration of nanofiller differing in average particle size (7 nm for Aerosil 380 and 40 nm for Nanosilica 999) on mechanical and thermomechanical properties was investigated. DMTA measurements showed that Nanosilica 999, irrespective of its concentration, slightly increased the value of the storage shear modulus G' but Aerosil 380 brings about a nearly opposite effect, the shear modulus in the rubber region decreases with increasing filler content. Very high elongations at break ranging from 800% to more than 1000%, as well as high tensile strengths illustrate excellent ultimate tensile properties of the prepared samples. The best mechanical and thermomechanical properties were found for the sample filled with 0.5 wt.% of Nanosilica 999.
A novel synthesis of perovskite bismuth ferrite nanoparticles
Authors: Biasotto Glenda , Simões Alexandre , Foschini César , Antônio Selma , Zaghete Maria , Varela Jose
Published: January 2013

Microwave assisted hydrothermal (MAH) method was used to synthesize crystalline bismuth ferrite (BiFeO3) nanoparticles (BFO) at temperature of 180?C with times ranging from 5 min to 1 h. For comparison, BFO powders were also crystallized by the soft chemistry route in a conventional furnace at a temperature of 850?C for 4 h. X-ray diffraction (XRD) results verified the formation of perovskite BFO crystallites while infrared data showed no traces of carbonate. Field emission scanning microcopy (FE/SEM) revealed a homogeneous size distribution of nanometric BFO powders. MAH method produced nanoparticles of 96% pure perovskite, with a size of 130 nm. These results are in agreement with Raman scattering values which show that the MAH synthesis route is rapid and cost effective. This method could be used as an alternative to other chemical methods in order to obtain BFO nanoparticles.
Synthesis of alumina/YAG 20 vol% composite by co-precipitation
Authors: Lach Radosław , Haberko Krzysztof , Bucko Mirosław
Published: January 2013

Co-precipitation of alumina/YAG precursor from aluminum and yttrium nitrate solution with ammonium carbonate results in dawsonite. Its crystallographic parameters differ from the compound precipitated with no yttrium additive. It suggests that yttrium ions become incorporated into the dawsonite structure. The DSC/ TG and X-ray diffraction measurements show decomposition of dawsonite at elevated temperatures resulting in ?-Al2O3 and then ?- and ?-alumina modifications. Full transformation to ?-Al2O3 and YAG occurs at temperatures higher than 1230?C. Starting powder for the sintering experiments was prepared using the coprecipitated precursor calcined at 600?C. Seeding of such powder with 5 wt.% ?-Al2O3 results in material of 98% density at 1500?C. Much lower densification show compacts of unseeded powder.
An Experimental Examination of Factors That Influence Auditor Assessments of a Deficiency in Internal Control over Financial Reporting
Authors: Gramling Audrey A. , O'Donnell Edward F. , Vandervelde Scott D.
Published: January 2013

SYNOPSIS

When assessing the effectiveness of internal control over financial reporting (ICFR), auditors evaluate design effectiveness, gather evidence on operating effectiveness, assess operating effectiveness, and conclude whether control deficiencies are material weaknesses. We experimentally examine audit managers' and partners' assessments of ICFR operating effectiveness and judgments of whether a control deficiency is a material weakness to determine the influence of the presence of: (1) a material weakness unrelated to the deficiency being assessed, and (2) a known misstatement associated with the identified control deficiency. Results suggest that the presence of either an unrelated material weakness or a known misstatement influences the assessed operating effectiveness of an internal control and the likelihood of a material weakness assessment. We also provide supplemental survey results from practicing audit managers and partners on their experiences in assessing potential material weaknesses to gain insights into their interpretations of the professional guidance.
A Model to Detect Potentially Fraudulent/Abnormal Wires of an Insurance Company: An Unsupervised Rule-Based Approach
Authors: Kim Yongbum , Vasarhelyi Miklos A.
Published: January 2013

Fraud prevention/detection is an important function of internal control. Prior literature focused mainly on fraud committed by external parties, such as customers. However, according to a survey by the Association of Certified Fraud Examiners (ACFE 2009), it was noted that employees posed the greatest fraud threat. This study proposes profiling fraud using an unsupervised learning method. The fraud detection model is based on potential fraud/anomaly indicators in the wire transfer payment process of a major insurance company in the United States. Each indicator is assigned an arbitrary score based on its severity. Once an aggregate score is calculated, those wire transfer payments whose total scores are above a threshold will be suggested for investigation. Our contribution is to report what we have learned and to document our findings using fraud/anomaly indicators to detect potential fraud and/or errors on real data from a major insurance company.
Pharmacokinetics of long-acting nalbuphine decanoate after intramuscular administration to Hispaniolan Amazon parrots (Amazona ventralis)
Authors: Guzman David Sanchez-Migallon , KuKanich Butch , Heath Timothy D. , Krugner-Higby Lisa A. , Barker Steven A. , Brown Carolyn S. , Paul-Murphy Joanne R.
Published: January 2013

Objective—To evaluate the pharmacokinetics of nalbuphine decanoate after IM administration to Hispaniolan Amazon parrots (Amazona ventralis).

Animals—9 healthy adult Hispaniolan Amazon parrots of unknown sex.

Procedures—Nalbuphine decanoate (37.5 mg/kg) was administered IM to all birds. Plasma samples were obtained from blood collected before (time 0) and 0.25, 1, 2, 3, 6, 12, 24, 48, and 96 hours after drug administration. Plasma samples were used for measurement of nalbuphine concentrations via liquid chromatography–tandem mass spectrometry. Pharmacokinetic parameters were estimated with computer software.

Results—Plasma concentrations of nalbuphine increased rapidly after IM administration, with a mean concentration of 46.1 ng/mL at 0.25 hours after administration. Plasma concentrations of nalbuphine remained > 20 ng/mL for at least 24 hours in all birds. The maximum plasma concentration was 109.4 ng/mL at 2.15 hours. The mean terminal half-life was 20.4 hours.

Conclusions and Clinical Relevance—In Hispaniolan Amazon parrots, plasma concentrations of nalbuphine were prolonged after IM administration of nalbuphine decanoate, compared with previously reported results after administration of nalbuphine hydrochloride. Plasma concentrations that could be associated with antinociception were maintained for 24 hours after IM administration of 37.5 mg of nalbuphine decanoate/kg. Safety and analgesic efficacy of nalbuphine treatments in this species require further investigation to determine the potential for clinical use in pain management in psittacine species.
Flow cytometric detection and procoagulant activity of circulating canine platelet-derived microparticles
Authors: Helmond Sarah E. , Catalfamo James L. , Brooks Marjory B.
Published: January 2013

Objective—To measure platelet membrane–derived microparticle (PMP) content and thrombin-generating capacity of canine plasma subjected to specific processing and storage conditions.

Animals—31 clinically normal dogs (19 males and 12 females).

Procedures—Citrate-anticoagulated blood samples obtained from each dog were centrifuged at 2,500 × g to isolate platelet-poor plasma (PPP), then PPP was centrifuged at 21,000 × g to isolate microparticle-free plasma (MPF) and microparticle-enriched plasma (MPEP). Whole blood and paired samples of fresh and frozen-thawed PPP, MPF, and MPEP were dual labeled for flow cytometric detection of membrane CD61 (constitutive platelet antigen) and annexin V (indicating phosphatidylserine externalization). Platelets and PMPs were enumerated with fluorescent, size-calibrated beads. Thrombin generation in fresh and frozen-thawed PPP, MPF, and MPEP was measured via kinetic fluorometric assays configured with low tissue factor and low phospholipid concentrations.

Results—Initial centrifugation yielded PPP with < 0.5% the platelets of whole blood, with median counts of 413 PMPs/μL for males and 711 PMPs/μL for females. Sequential centrifugation resulted in a 10-fold concentration of PMPs in MPEP and virtually depleted PMPs from MPF. Thrombin generation depended on PMP content, with median endogenous thrombin potential of 0, 893, and 3,650 nmol•min for MPF, PPP, and MPEP, respectively. Freeze-thaw cycling caused significant increases in PMP counts and phosphatidylserine externalization.

Conclusions and Clinical Relevance—Canine PMPs were major determinants of thrombin-generating capacity; preanalytic variables influenced plasma PMP content. Processing conditions described here may provide a basis for characterization of PMPs in clinical studies of thrombosis in dogs.
Pharmacokinetics of N-acetylcysteine after oral and intravenous administration to healthy cats
Authors: Buur Jennifer L. , Diniz Pedro P. V. P. , Roderick Kursten V. , KuKanich Butch , Tegzes John H.
Published: January 2013

Objective—To describe the pharmacokinetics of N-acetylcysteine (NAC) in healthy cats after oral and IV administration.

Animals—6 healthy cats.

Procedures—In a crossover study, cats received NAC (100 mg/kg) via IV and oral routes of administration; there was a 4-week washout period between treatments. Plasma samples were obtained at 0, 5, 15, 30, and 45 minutes and 1, 2, 4, 8, 12, 24, 36, and 48 hours after administration, and NAC concentrations were quantified by use of a validated high-performance liquid chromatography–mass spectrometry protocol. Data were analyzed via compartmental and noncompartmental pharmacokinetic analysis.

Results—Pharmacokinetics for both routes of administration were best described by a 2-compartment model. Mean ± SD elimination half-life was 0.78 ± 0.16 hours and 1.34 ± 0.24 hours for the IV and oral routes of administration, respectively. Mean bioavailability of NAC after oral administration was 19.3 ± 4.4%.

Conclusions and Clinical Relevance—The pharmacokinetics of NAC for this small population of healthy cats differed from values reported for humans. Assuming there would be similar pharmacokinetics in diseased cats, dose extrapolations from human medicine may result in underdosing of NAC in cats with acute disease. Despite the low bioavailability, plasma concentrations of NAC after oral administration at 100 mg/kg may be effective in the treatment of chronic diseases.
Precision and accuracy of clinical illness scores, compared with pulmonary consolidation scores, in Holstein calves with experimentally induced Mycoplasma bovis pneumonia
Authors: Amrine David E. , White Brad J. , Larson Robert , Anderson David E. , Mosier Derek A. , Cernicchiaro Natalia
Published: January 2013

Objective—To determine the precision of a clinical illness score (CIS) system for identification of clinical signs in calves with experimentally induced Mycoplasma bovis pneumonia and to evaluate the accuracy of CISs in relation to pulmonary consolidation scores assigned at necropsy.

Animals—178 Holstein bull calves that were 52 to 91 days of age at the time of pneumonia induction.

Procedures—5 trials involved calves challenged with M bovis and scheduled for euthanasia and necropsy 12 to 24 days afterward. Nine veterinarian observers with various degrees of experience simultaneously assigned CISs to calves within 48 hours before necropsy. The precision of the CIS system among observers was evaluated via the Cohen κ statistic. The accuracy of each observer's CISs relative to 6 cutoffs (≥ 5%, ≥ 10%, ≥ 15%, ≥ 20%, ≥ 25%, and ≥ 30%) of percentage pulmonary consolidation was determined by comparing prenecropsy CISs with the gross pulmonary consolidation scores assigned at necropsy. Estimates for sensitivity and specificity were calculated relative to the 6 pulmonary consolidation cutoffs.

Results—A slight level of agreement was evident among observers (κ range, 0.10 to 0.21 for the individual trials) and overall (κ = 0.16; 95% confidence interval, 0.10 to 0.24). Median sensitivity and specificity changed with pulmonary consolidation score cutoff. Median sensitivity for all observers ranged from 81.7% to 98.9%, and median specificity ranged from 80.8% to 94.9% over all cutoff values.

Conclusions and Clinical Relevance—Agreement among observers assigning CISs to calves was low; the accuracy of the CIS system in relation to that of pulmonary consolidation scoring varied with the severity of consolidation considered to represent bovine respiratory disease.
Evaluation of the efficacy and safety of single administration of 4.7-mg deslorelin acetate implants on egg production and plasma sex hormones in Japanese quail (Coturnix coturnix japonica)
Authors: Petritz Olivia A. , Sanchez-Migallon Guzman David , Paul-Murphy Joanne , Fecteau Kellie , Mete Aslı , Kass Philip H. , Hawkins Michelle G.
Published: January 2013

Objective—To evaluate the effects of 4.7-mg deslorelin acetate implants on egg production and plasma concentrations of 17β-estradiol and androstenedione in Japanese quail (Coturnix coturnix japonica) over 180 days and assess safety of the implants in quail via gross and histologic examination.

Animals—20 female Japanese quail.

Procedures—Following a 7-day period of consistent egg laying, quail were anesthetized and received a 4.7-mg deslorelin implant (treatment group; n = 10) or identical placebo implant (control group; 10) SC between the scapulae. Egg production was monitored daily. Plasma concentrations of 17β-estradiol and androstenedione were measured on days 0 (immediately prior to implant injection), 14, 29, 62, 90, 120, 150, and 180 via radioimmunoassay. Birds were weighed periodically and euthanized at day 180 for complete necropsy.

Results—Egg production was significantly decreased in the treatment group, compared with the control group, from 2 to 12 weeks after implant injection. Egg production ceased in 6 of 10 quail in the treatment group (mean duration of cessation, 70 days). Plasma androstenedione and 17β-estradiol concentrations were significantly lower on day 29 in the treatment group than in the control group. Plama androstenedione and 17β-estradiol concentrations were significantly lower on day 29 in the treatment group then in the control group.

Conclusions and Clinical Relevance—4.7-mg deslorelin acetate implants reversibly decreased egg laying for approximately 70 days in most of the Japanese quail evaluated. Further studies evaluating implants containing different concentrations of the drug are needed in quail and other avian species.
Anticoagulant rodenticide screening in dogs: 123 cases (1996–2003)
Authors: Waddell Lori S. , Poppenga Robert H. , Drobatz Kenneth J.
Published: January 2013

Objective—To identify dogs with anticoagulant rodenticide (AR) screens submitted, determine whether detected concentrations of the anticoagulants correlated with severity of clinical signs for dogs with positive results on AR screens, and identify the most common disease processes present and the prognosis for those with negative AR screens.

Design—Retrospective case series.

Animals—123 dogs.

Procedures—History, signalment, clinical signs, physical examination findings, PCV, total solids concentration, prothrombin time, activated partial thromboplastin time, platelet count, AR concentrations, duration of hospitalization, blood products administered, final diagnosis, and outcome were recorded from medical records of dogs that underwent AR toxicology screenings.

Results—75 of 123 (60.9%) dogs tested positive for AR. Dogs tested positive for brodifacoum, diphacinone (also called diphenadione), and chlorophacinone. Dogs with positive AR screenings weighed significantly less, received significantly more fresh frozen plasma, had significantly longer initial prothrombin time, and were significantly more likely to survive, compared with those with negative screens. Anticoagulant rodenticide concentrations ranged from trace amounts to 1,120 parts per billion and were not correlated with any recorded parameter. The most common conditions diagnosed in the 48 dogs with negative screens included neoplasia in 15 (31.3%), immune-mediated disease in 7 (14.6%), and gastrointestinal bleeding in 5 (10.4%) dogs.

Conclusions and Clinical Relevance—AR concentrations were not correlated with severity of clinical signs or the degree of prolongation of coagulation times in this series of patients. Patients with severe coagulopathies but negative results of AR screening had a poor prognosis, with neoplasia as the most common diagnosis. Anticoagulant rodenticide intoxication had the best prognosis, with a survival rate of 98.7% in this study.
Oleander toxicosis in equids: 30 cases (1995–2010)
Authors: Renier Anna C. , Kass Philip H. , Magdesian K. Gary , Madigan John E. , Aleman Monica , Pusterla Nicola
Published: January 2013

Objective—To determine clinical, laboratory analysis, and necropsy findings for equids with oleander toxicosis and to identify factors associated with outcome.

Design—Retrospective case series.

Animals—30 equids.

Procedures—Medical records of equids with detectable concentrations of oleandrin in serum, plasma, urine, or gastrointestinal fluid samples and equids that had not received cardiac glycoside drugs but had detectable concentrations of digoxin in serum were identified via a medical records database search. Descriptive statistics were calculated for medical history, physical examination, laboratory analysis, and necropsy variables. Logistic regression analysis was used to identify physical examination and laboratory analysis factors significantly associated with outcome.

Results—3 of 30 (10.0%) equids died before or immediately after arrival at the hospital. Of the other 27 equids, 23 (85.2%) had gastrointestinal tract abnormalities, azotemia was detected for 19 (70.4%), and a cardiac arrhythmia was ausculted for 18 (66.7%). Mortality rate for all equids was 50.0%; mortality rate for hospitalized equids was 44.4%. The most common cause of death was cardiac dysfunction. Odds of survival to discharge from the hospital were lower for equids with cardiac arrhythmias versus those without arrhythmias and decreased with increasing Hct and serum glucose concentrations. Odds of survival increased with increasing serum chloride concentration and duration of hospitalization.

Conclusions and Clinical Relevance—Equids with oleander toxicosis frequently had simultaneous gastrointestinal tract, cardiac, and renal problems. Oleander intoxication should be a differential diagnosis for equids with colic in geographic areas where oleander is found, especially when azotemia or cardiac arrhythmias are detected concurrently.
Preparation of sterically stabilized gold nanoparticles for plasmonic applications
Authors: Benkovičová Monika , Végsö Karol , Šiffalovič Peter , Jergel Matej , Majková Eva , Luby Štefan , Šatka Alexander
Published: January 2013

Plasmonic nanoparticles such as those of gold or silver have been recently investigated as a possible way to improve light absorption in thin film solar cells. Here, a simple method for the preparation of spherical plasmonic gold nanoparticles in the form of a colloidal solution is presented. The nanoparticle diameter is controlled in the range from several nm to tens of nm depending on the synthesis parameters with the size dispersion down to 14 %. The synthesis is based on thermal decomposition and reduction of the chloroauric acid in the presence of a stabilizing capping agent (surfactant) that is very slowly injected into the hot solvent. The surfactant prevents uncontrolled nanoparticle aggregation during the growth process. The nanoparticle size and shape depend on the type of the stabilizing agent. Surfactants with different lengths of the hydrocarbon chains such as Z-octa-9-decenylamine (oleylamine) with AgNO3 and polyvinylpyrrolidone with AgNO3 were used for the steric stabilization. Hydrodynamic diameter of the gold nanoparticles in the colloidal solution was determined by dynamic light scattering while the size of the nanoparticle metallic core was found by small-angle X-ray scattering. The UV-VIS-NIR spectrophotometer measurements revealed a plasmon resonance absorption in the 500–600 nm range. Self-assembled nanoparticle arrays on a silicon substrate were prepared by drop casting followed by spontaneous evaporation of the solvent and by a modified Langmuir-Blodgett deposition. The degree of perfection of the self-assembled arrays was analyzed by scanning electron microscopy and grazing-incidence small-angle X-ray scattering. Homogeneous close-packed hexagonal ordering of the nanoparticles stretching over large areas was evidenced. These results document the viability of the proposed nanoparticle synthesis for the preparation of high-quality plasmonic templates for thin film solar cells with enhanced power conversion efficiency, surface enhanced Raman scattering, and other applications.
Chemical degradation of polyaniline by reaction with Fenton’s reagent — a spectroelectrochemical study
Authors: Sedenkova Ivana , Dannenberg Felix , Younadam Nora , Holze Rudolf
Published: January 2013

Changes in the various chemical and structural properties of polyaniline (PANI) films effected by interaction with Fenton’s reagent are monitored with electrochemical in situ spectroscopic and surface-sensitive techniques. Starting from a model of possible structural changes caused by chemical attack of species generated by Fenton’s reagent, particular attention is paid to the differences between the compact and highly porous (open) forms of PANI.
Establishing Effective Linear Temperature Gradients for Ultrathin Bonded Concrete Overlays on Asphalt Pavements
Authors: Mu Feng , Vandenbossche Julie M.
Published: January 2013

The effective linear temperature gradient is a significant input needed to characterize the effects of environmental loadings when available pavement design procedures are used for bonded concrete overlays on asphalt (BCOA), also known as thin or ultrathin whitetopping. Establishing such an input is challenging and therefore has not been well guided in current BCOA design procedures across the country. Guidance is provided on suitable values for the effective equivalent linear temperature gradient (EELTG) that can be used in the design of ultrathin BCOAs. The EELTG is expressed as a function of the climatic conditions, geographical location, and design features of the BCOA: longitude, latitude, elevation, annual mean percentage of sunshine, overlay panel size, 28-day modulus of rupture for the portland cement concrete, and thickness of the hot-mix asphalt layer. Typical values for the annual mean percentage of sunshine are recommended to facilitate implementation of the proposed guideline in the current design procedures.
Rational Use of Terminal Anchorages in Portland Cement Concrete Pavement
Authors: Ryu Sung Woo , Jaiswal Harshita , Choi Seongcheol , Senadheera Sanjaya , Jayawickrama Priyantha , Won Moon C.
Published: January 2013

Portland cement concrete (PCC) pavements have long been thought to expand and push bridge structures, with bridge damage resulting. To protect bridge structures from expanding PCC pavements, three terminal systems are currently used in Texas: anchor lug (AL), wide flange (WF), and expansion joint (EJ). Even though the Texas Department of Transportation uses all three systems in continuously reinforced concrete pavement (CRCP), the effectiveness of these three systems has not been fully evaluated. The parameters affecting CRCP movement near bridge terminal areas are investigated: whether thermal expansion of CRCP is damaging bridge structures, and if so, which terminal type is most cost-effective. Extensive field evaluations reveal that slab movement at the end of the CRCP are substantially restrained by subbase friction. Slab length from the end of the CRCP that significantly contributes to slab movement is limited to about 200 ft (60.96 m) for the CRCP system with asphalt base typically used in Texas. Slab movement rates due to seasonal temperature variations are larger than daily slab movement rates. The movement at the end of the CRCP can be accommodated by a simple EJ with subbase friction, which can be achieved with typical asphalt-stabilized base. The use of an AL system is not needed to restrain concrete slab movement. The benefits of WF and AL systems are doubtful when one considers that their cost is higher than that of the simpler EJ system.