bluuebunny/crossref_metadata_2025 huggingface dataset:
Wind Turbine Fault Detection through Principal Component Analysis and Statistical Hypothesis Testing
Authors: Pozo Francesc , Vidal Yolanda
Published: October 2016

This work addresses the problem of online fault detection of an advanced wind turbine benchmark under actuators (pitch and torque) and sensors (pitch angle measurement) faults of different type. The fault detection scheme starts by computing the baseline principal component analysis (PCA) model from the healthy wind turbine. Subsequently, when the structure is inspected or supervised, new measurements are obtained and projected into the baseline PCA model. When both sets of data are compared, a statistical hypothesis testing is used to make a decision on whether or not the wind turbine presents some fault. The effectiveness of the proposed fault-detection scheme is illustrated by numerical simulations on a well-known large wind turbine in the presence of wind turbulence and realistic fault scenarios.
Data Evaluation in Smart Sensor Networks Using Inverse Methods and Artificial Intelligence (AI): Towards Real-Time Capability and Enhanced Flexibility
Authors: Bosse Stefan , Lechleiter Armin , Lehmhus Dirk
Published: October 2016

Data evaluation is crucial for gaining information from sensor networks. Main challenges include processing speed and adaptivity to system change, both prerequisites for SHM-based weight reduction via relaxed safety factors. Our study looks at soft real time solutions providing feedback within defined but flexible, application-controlled intervals. These can rely on minimizing computation/communication latencies e.g. by parallel computation. Strategies towards this aim can be model-based, including inverse FEM, or model-free, including machine learning, which in practice bases training on a defined system state, too, hence also facing challenges at state changes. We thus introduce hybrid data evaluation combining multi-agent based systems (MAS) with inverse FEM, mainly relying on matrix operations that can be partially distributed: The MAS perform sensor data acquisition, aggregation, pre-computation, and finally application (the LM/SHM itself and higher information processing and visualization layers, i.e., WEB interfaces). System capabilities are evaluated against a virtual test case, demonstrating enhanced stability and reliability. Besides, we analyze system performance under conditions of in-service change and discuss system layouts suited to improve coverage of this issue.
Shape Memory Alloys Wires: From Small to Medium Diameter
Authors: Torra Vicenç , Casciati Sara , Vece Michele
Published: October 2016

The use of Shape Memory Alloys in dampers devices able to reduce the wind, rain or traffic induced oscillations in stayed cables is well represented in the literature. An analysis realized on standard cables at existing facilities shows the reliable efficiency of the SMA wire in damping oscillations. Such studies also provide tools to build the SMA dampers and to account for the effects of the external temperature in the SMA. The particular study reported in this paper focuses on a critical discussion on the relation between the wire diameter and macroscopic behavior and external temperature effects. The damping requires the absorption of the mechanical energy and its conversion to heat via the action of hysteresis cycles. The study was realized on wires of different diameters. In particular, the study centers on wires of diameter 0.2, 0.5 and 2.46 mm. The flat cycles showed by the thin wires (i.e., diameter 0.2 and 0.5 mm) and the non-classical S-shaped cycles of wires of diameter 2.46 mm establish clear differences of the response under external summer-winter temperature actions. Depending of the room temperature and SMA composition, a complete flat transformation in thin wires requires stresses, in general, near 300-400 MPa. A complete transformation for an S-shaped cycle need stresses as higher as 600 MPa. The analysis of the behavior of these wires under the action of warm temperatures in summer and cold temperatures in winter, suggests that thin wires lose their pseudo-elastic state in winter. The S-shaped permits positive working in extended temperature domain and a supplementary investigation establishes that S-shaped can be increased by strain aging. The hysteretic behavior in S-shaped permits practical working under external temperatures as applications in bridges require. From a fundamental point of view, the flat cycles are coherent with the classical treatment of the SMA as a first order phase transition but the S-shaped can be considered associated to an anomaly in heat capacity.
Functionalizing Surface Electrical Potential of Hydroxyapatite Coatings
Authors: Pluduma Liene , Freimanis Edijs , Gross Karlis Agris , Koivuluoto Heli , Algate Kent , Haynes David , Vuoristo Petri
Published: October 2016

While considerable work has been done on chemically functionalizing hydroxyapatite, little has been done on tailoring the electrical surface potential. This has been due to limitations in the available methods to impart a surface charge. Work to date has charged conventionally manufactured hydroxyapatite exhibiting a random crystal orientation. At the outset, the microstructure has not been optimized for the highest surface potential. The aim of this work was to both orient the crystals as well as fill the structure with hydroxyl ions for further increasing the surface electrical potential. We used hydroxyapatite coatings with the same topography, but different hydroxyl ion concentration; this altered the surface potential that was measured by Kelvin probe AFM. Results indicate that a greater hydroxyl ion concentration increases the surface potential of the hydroxyapatite coating. Coatings with a higher surface potential showed improved biological response, measured as osteoblast attachment and osteoblast related gene expression.
Developmentally Inspired Approach to Cartilage Tissue Engineering
Authors: Jabbari Esmaiel
Published: October 2016

Structural organization of articular cartilage is rooted in the arrangement of mesenchymal stem cells (MSCs) into morphologically distinct zones during embryogenesis as a result of spatiotemporal gradients in biochemical, mechanical, and cellular factors that direct the formation of stratified structure of articular cartilage. These gradients are central to the function of cartilage as an articulating surface. Strategies that mimic zonal organization of articular cartilage are more likely to create an engineered tissue with more effective clinical outcome. The objective of this work was to measure the expression of human MSCs encapsulated in engineered gels that simulate stiffness of the superficial, middle and calcified zones of articular cartilage supplemented with zone specific growth factors. Size of the encapsulated cells increased from the gel simulating superficial zone to those simulating middle and calcified zones. Glycosaminoglycans (GAG) content progressively increased from the gel simulating superficial zone to those simulating middle and calcified zones. Human MSCs in the gel simulating the superficial zone showed up-regulation of Sox-9 and SZP whereas those in the calcified gel showed up-regulation of ALP. Results demonstrate that a developmental approach can potentially regenerate the zonal structure of articular cartilage.
Relaxor Single-Crystal Plates with Nano-Size Ferroelectric Domains Applying to Ultrasonic Prove for Medical Uses
Authors: Ogawa Toshio , Ikegaya Taiki
Published: October 2016

Sound velocities were measured in relaxor single-crystal plates, included in piezoelectric transducers for medical uses, using an ultrasonic precision thickness gauge with high-frequency pulse generation. The velocities were compared with the ones of piezoelectric ceramics in order to clarify characteristics of the single crystals. Estimating the difference in the sound velocities and elastic constants in the single crystals and ceramics, it was possible to evaluate effects of domain and grain boundaries on elastic constants. Existence of domain boundaries in single crystal affected the decrease in Young’s modulus, rigidity, Poisson’s ratio and bulk modulus. While existence of grain boundaries affected the decrease in Young’s modulus and rigidity, Poisson’s ratio and bulk modulus increased. It was thought these phinomina come from domain alignment by DC poling, and both the boundaries act as to absorb mechanical stress by defects due to the boundaries. In addition, the origin of piezoelectricity in single crystals is caused by low bulk modulus and Poisson’s ratio, and high Young’s modulus and rigidity in comparison with ceramics. On the contrary, the origin of piezoelectricity in ceramics is caused by high Poisson’s ratio by high bulk modulus, and furthermore, low Young’s modulus and rigidity due to domain alignment.
A Stretchable and Flexible Platform for Epidermal Electronics
Authors: Meyer Marcin , Van Bình Nguyen , Calero Venancio , Baraban Larysa , Rogers John , Cuniberti Gianaurelio
Published: October 2016

The society is aging and therefore there is a need for new mobile and reliable health monitoring systems. An idea of such wireless, stretchable and mobile health monitoring platform has been developed. It consists of a wireless stretchable, biocompatible sensor tag placed on the skin and an RFID reader collecting and evaluating all the data, which are then shown on the display.
A Direct Comparison of Glassy Carbon and PEDOT-PSS Electrodes for High Charge Injection and Low Impedance Neural Interfaces
Authors: Vomero Maria , Castagnola Elisa , Maggiolini Emma , Ciarpella Francesca , Rembado Irene , Goshi Noah , Fadiga Luciano , Kassegne Samuel , Ricci Davide
Published: October 2016

For neural applications, materials able to interface with the brain without harming it while recording high-fidelity signals over long-term implants are still sought after. Glassy Carbon (GC) and Poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT-PSS) have proved to be promising materials for neural interfaces as they show – compared to conventional metal electrodes - higher conductivity, better electrochemical stability, very good mechanical properties and therefore seem to be very promising for in vivo applications. We present here, for the first time, a direct comparison between GC and PEDOT-PSS microelectrodes in terms of biocompatibility, electrical and electrochemical properties as well as in vivo recording capabilities, using electrocorticography microelectrode arrays located on flexible polyimide substrate. The GC microelectrodes were fabricated using a traditional negative lithography processes followed by pyrolysis. PEDOT-PSS was selectively electrodeposited on the desired electrodes. Electrochemical performance of the two materials was evaluated through electrochemical impedance spectroscopy and cyclic voltammetry. Biocompatibility was assessed through in-vitro studies evaluating cultured cells viability. The in vivo performance of the GC and PEDOT-PSS electrodes was directly compared by simultaneously recording neuronal activity during somatosensory stimulation in Long-Evans rats. We found that both GC and PEDOT-PSS electrodes outperform metals in terms of electrochemical performance and allow to obtain excellent recordings of somatosensory evoked potentials from the rat brain surface. Furthermore, we found that both GC and PEDOT-PSS substrates are highly biocompatible, confirming that they are safe for neural interface applications.
Recording High Frequency Neural Signals Using Conformable and Low-Impedance ECoG Electrodes Arrays Coated with PEDOT-PSS-PEG
Authors: Castagnola Elisa , Marrani Marco , Maggiolini Emma , Maita Francesco , Pazzini Luca , Polese Davide , Pecora Alessandro , Maiolo Luca , Fortunato Guglielmo , Fadiga Luciano , Ricci Davide
Published: October 2016

Electrocorticography (ECoG) is receiving growing attention for both clinical and research applications thanks to its reduced invasiveness and ability of addressing large cortical areas. These benefits come with a main drawback, i.e. a limited frequency bandwidth. However, recent studies have shown that spiking activity from cortical neurons can be recorded when the ECoG grids present the following combined properties: (I) conformable substrate, (II) small neuron-sized electrodes with (III) low-impedance interfaces. We introduce here an ad-hoc designed ECoG device for investigating how electrode size, interface material composition and electrochemical properties affect the capability to record evoked and spontaneous neural signals from the rat somatosensory cortex and influence the ability to record high frequency neural signal components.Contact diameter reduction down to 8 μm was possible thanks to a specific coating of a (3,4-ethylenedioxytiophene)-poly (styrenesulfonate)-poly-(ethyleneglycol) (PEDOT-PSS-PEG) composite that drastically reduces impedance and increases electrical and ionic conductivities. In addition, the extreme thinness of the polyimide substrate (6 - 8 μm) and the presence of multiple perforations through the device ensure an effective contact with the brain surface and the free flow of cerebrospinal fluid. In-vivo validation was performed on rat somatosensory cortex.
Role of Interstitial Oxygen Atom on Martensitic Transformation of Ti-Nb Alloy
Authors: Tahara Masaki , Inamura Tomonari , Kim Hee Young , Miyazaki Shuichi , Hosoda Hideki
Published: October 2016

The effect of oxygen content on the stability of α′′ martensite phase of the Ti-20mol%Nb alloy was investigated by differential scanning calorimetry. The reverse martensitic transformation temperature increased with increasing oxygen content, and this means that α′′ martensite phase was stabilized by oxygen addition. The mechanism of α′′ martensite stabilization by oxygen atoms was discussed based on the changes in the lattice parameters of α′′ martensite.
Mechanical and Superelastic Properties of Au-51Ti-18Co Biomedical Shape Memory Alloy Heat-Treated at 1173 K to 1373 K
Authors: Buasri Taywin , Shim Hyunbo , Tahara Masaki , Inamura Tomonari , Goto Kenji , Kanetaka Hiroyasu , Yamabe-Mitarai Yoko , Hosoda Hideki
Published: October 2016

The effect of heat treatment temperature from 1173 K to 1373 K for 3.6 ks on mechanical and superelastic properties of an Ni-free Au-51Ti-18Co alloy (mol%) was investigated. The stress for inducing martensitic transformation (SIMT) and the critical stress for slip deformation (CSS) slightly decrease with increasing the heat–treatment temperature. Regardless of heat–treatment temperature, good superelasticity was definitely recognized with the maximum shape recovery ratio up to 95 % and 4 % superelastic shape recovery strain. As the mentioned reasons, the Au-51Ti-18Co alloy is promising for practical biomedical applications.
Mechanical Properties of Nanoceramic Zirconia Coatings on NiTi Orthodontic Wires
Authors: Lopes Natalia Isabel de Azevedo , de Arruda Santos Leandro , Lopes Buono Vicente Tadeu
Published: October 2016

Nickel-titanium (NiTi) alloys have been largely applied in biomedical devices due to their special properties of superelasticity and shape memory. Even though NiTi generally displays good corrosion resistance and biocompatibility, mechanical fatigue and fretting-corrosion resistance remain important challenges in a number of applications, since it can accelerate nickel ions releasing, that have been reported as cytotoxic, mutagenic, and allergenic. This study aims to develop an appropriate coating to help delaying crack nucleation and corrosion in NiTi alloys. Zirconia (ZrO2) coating stands as a good candidate to improve the corrosion and wear resistance of metallic substrates and, in this work, it was obtained by electrodeposition on NiTi superelastic and shape memory orthodontic wires. The surface morphology and the chemical composition of the coated samples were evaluated using scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), and atomic force microscopy (AFM). The mechanical response was evaluated by three-point bending tests. The results showed that the ZrO2 layer was uniform and well adhered to the NiTi subtract. Additionally, it was observed that this coating was capable of undergoing severe deformation without cracking, indicating a potential increase in fatigue resistance of the conjugate.
Structural Effects of Thermomechanical Processing on the Static and Dynamic Responses of Powder Metallurgy Fe-Mn-Si Based Shape Memory Alloys
Authors: Mihalache Elena , Pricop Bogdan , Comăneci Radu Ioachim , Suru Marius Gabriel , Lohan Nicoleta Monica , Mocanu Mihai , Özkal Burak , Bujoreanu Leandru Gheorghe
Published: October 2016

Fe-14Mn-6Si-9Cr-5Ni (wt. %) shape memory alloys (SMAs) were produced by powder metallurgy (PM) combined with Mechanical Alloying (MA). The specimens were pressed and sintered under Ar atmosphere from as blended powders as well as from mixtures of as blended and 10, 20, 30 and 40 vol. % MA’ed powders, respectively. The five groups of sintered specimens were hot-rolled, spark-erosion cut and solution treated at five temperatures (923, 1023, …, 1373K/ 300 s/ water). Tensile loading-unloading tests were performed in order to obtain stress-induced martensite at different pre-straining degrees. The static responses of the twenty five types of specimens were evaluated by means of the surface areas under unloading curve (E2) and between loading and unloading curves (E1) which were used for determining static internal friction, Q-1. The dynamic responses of the undeformed specimens were determined by Dynamic Mechanical Analysis (DMA) performed at room temperature with a three-point-bending specimen holder in strain sweep mode. The structure of the twenty five specimens was analyzed X-ray diffraction. The effects of MA fraction were correlated with static and dynamic responses via structural changes.
Mutual Conversion between Stretched and Contracted Helices and its External Stimuli Induced Drastic Colors and Geometrical Structures Changes of Substituted Polyacetylenes Prepared with an Organo-Rhodium Catalyst
Authors: Tabata Masayoshi , Mawatari Yasuteru , Yoshida Yoshiaki , Sasaki Takahiro
Published: October 2016

Unique conversions between stretched and contracted helices of mono-substituted polyacetylenes (SPA)s prepared with an organo rhodium complex-amine catalytic system were demonstrated. The conversions of aromatic SPAs with a drastic color change were caused by polymerization solvents used, substituents in the phenyl ring, and external stimuli like heat- and solvent-treatments which were induced in the solid state. The helices of aliphatic polyacetylenes was oscillating just like spring or coil which was synchronizing with the restricted rotation around the ester O-*C bond in the solution. The oscillation mode was named as an accordion-like helix oscillation “HELIOS”. All the conversions were attributed to the difference of the thermodynamical stability between stretched and contracted helices.
Obtaining and Characterizing Nylon 6.12-Pseudoboehmite Nanocomposites - Mechanic Tests
Authors: Munhoz Jr. Antônio Hortêncio , do Nascimento Alber Luiz , Denuzzo Cesar , Gomes Gabriel Cavalcante , de Miranda Leila Figueiredo , Rossi Maura Vincenza
Published: October 2016

Polymer nanocomposites are formed by nanometrical particles embedded in a matrix. Additions of small amounts of nanoparticles of inorganic material in polymer matrixes can greatly improve mechanical properties when compared with the pure polymer. The high specific surface area of the inorganic nanoparticle materials promotes its dispersion in the polymeric matrix and the resulting properties are strongly related to the homogeneity of the dispersion. In the present work, nylon 6.12 nanocomposites with aged pseudoboehmite were obtained using octadecylamine to improve the union between the polymer and the pseudoboehmite. The nanocomposites were characterized by thermal and mechanical test. The pseudoboehmite was characterized by scanning electron microscopy and x-ray diffraction. The nanocomposite was characterized by tensile strength test, 3 points bending test and impact Izod resistance test. The addition of pseudoboehmite promote the increase of the elasticity modulus evidencing the interaction of the pseudoboehmite with the polymeric matrix, probably modifying its crystalline structure. The addition of pseudoboehmite promoted an increase in the HDT an Vicat temperatures of the nanocomposite.
IPMC Actuators Fabricated Using MEMS Technology
Authors: Tsuchitani Shigeki , Kikuchi Kunitomo , Shimizu Ippei , Taniguchi Tomohisa , Miki Hirofumi
Published: October 2016

Fabrication of ionic polymer metal composite (IPMC) on Si substrate and micromachining of IPMC are basic technologies for developing MEMS devices using IPMC. Adhesion of IPMC with the substrate is essential to fabricate IPMC on the substrate. Swelling of IPMC with water makes IPMC peel from the substrate due to the internal stress. To enlarge adhesion force of IPMC with the Si substrate, we have fabricated IPMC on an anodic-oxidized porous Si surface, which dramatically increased adhesion area between the IPMC and the substrate. Fabricated IPMC didn't peel from the Si substrate during the operation in water. Photolithography is a key technology in MEMS fabrication. However, water and organic solvents used in the fabrication process also swell IPMC and lower machining accuracy. We have developed a machining technology of microminiaturized IPMC by mainly using dry processes: reactive ion etching of Nafion film through metal mask, and a selective electrode formation using a plasma irradiation on Nafion and an electroless gold plating. An array of IPMCs with a width of 100 μm was fabricated and their operations in water were confirmed.
Novel Behavior in Smart Polymeric Materials: Stress Memory and its Potential Applications
Authors: Hu Jin Lian , Narayana Harishkumar
Published: October 2016

Materials, structures and systems, responsive to an external stimulus are smart and adaptive to our human demands. Among smart materials, polymers with shape memory effect are at the forefront of research leading to comprehensive publications and wide applications. In this paper, we extend the concept of shape memory polymers to stress memory ones, which have been discovered recently. Like shape memory, stress memory represents a phenomenon where the stress in a polymer can be programmed, stored and retrieved reversibly with an external stimulus such as temperature and magnetic field. Stress memory may be mistaken as the recovery stress which was studied quite broadly. Our further investigation also reveals that stress memory is quite different from recovery stress containing multi-components including elastic and viscoelastic forces in addition to possible memory stress. Stress memory could be used into applications such as sensors, pressure garments, massage devices, electronic skins and artificial muscles. The current revelation of stress memory potentials is emanated from an authentic application of memory fibres, films, and foams in the smart compression devices for the management of chronic and therapeutic disorders.
Graphene-Boron Nitride 2D Heterosystems Functionalized with Hydrogen: Structure, Vibrations, Optical Response, Electron Band Engineering and Bonding
Authors: Shkrebtii Anatoli I. , Wilk Benjamin , Minnings Robert , Zapata-Penã Reinaldo , Anderson Sean M. , Mendoza Bernardo S. , Kupchak Ihor M.
Published: October 2016

We characterise from first principles the structure and bonding in 2D heterosystems made of bilayers or trilayers of graphene and graphene-like-materials (GLMs), stacked on top of each other, and functionalized using hydrogen. The effects of electron band gap opening and tuning, as well as formation of strongly bonded multilayers have been predicted. The linear and nonlinear optical and vibrational spectra were modelled for hydrogenated alternating graphene monolayers with insulating hexagonal boron nitride (h-BN) films. Here we focus mostly on the structural aspect of the 2D heterosystems. The simulated atomic and related electron structures indicate that submonolayer hydrogenation of the outer surfaces of multilayer systems induces covalent interlayer bonds and enables electron gap engineering in otherwise gapless graphene or wide-band gap h-BN. Calculated structural, vibrational, electronic and optical properties of the systems of interest aim to enabling in-situ noninvasive characterization of graphene based multilayers.
Luminescence Properties of Ytterbium Activated PLZT Ceramics
Authors: Plonska Malgorzata , Pisarski Wojciech A. , Pisarska Joanna
Published: October 2016

In the present work the influence of co-doping with ytterbium ions (for 0, 0.5, 1.5, 2.5 wt.% of Yb3+) on physical properties of 8/65/35 PLZT was studied. The ceramic powders were synthesized by the modified sol-gel method, and underwent consolidation by the pressure-less sintering techniques, in Ts=1200°C/6h. Our investigations give a detailed account of the relationships between concentrations of trivalent ytterbium ions in PLZT matrix, on their structure, microstructure, as well as luminescence properties. Near-infrared luminescence spectra at about 1020 nm were registered, which correspond to 2F5/2 - 2F7/2 transition of Yb3+. Based on decay measurements, the luminescence lifetimes for the 2F5/2 excited state of Yb3+ were determined. Luminescence decay analysis indicates that the 2F5/2 lifetime increase with increasing activator concentration (Yb3+) in PLZT ceramic matrix.
Some Perspectives in Non-Hermitian Metamaterials
Authors: Savoia Silvio , Castaldi Giuseppe , Galdi Vincenzo
Published: October 2016

We provide a compact review of some recent results on non-Hermitian metamaterials characterized by spatial modulation of loss and gain. First, we present a systematic synthesis procedure based on a complex-coordinate extension of the transformation-optics paradigm, which admits an insightful interpretation in conjunction with the "complex-source-point" formalism. Subsequently, we study some waveguiding phenomena that can occur in bilayers satisfying the parity-time symmetry condition in the "epsilon-near-zero" regime.
Sensitivity and Selectivity of SnO2-Based Sensor for CO and H2 Detections: A Novel Method to Detect Simultaneously the CO and H2 Concentrations
Authors: Guo Xing Min , Zhao Jie Ting , Yin Xi Tao , Huang Shuang Long
Published: October 2016

SnO2-based sensor has many advantages such as low cost, small size, high reliability, and long operating life, but selectivity has been a major obstacle on the application for discriminating gas species in mixture of multi-reduction gases. To resolve the problem in this work, the pure SnO2 and NiO-, CuO- and Pt-modifying SnO2 as sensing materials were prepared by sol-gel method, the sensor cells were fabricated and characteristics of sensitivity and selectivity of the sensor cells to CO and H2 at 400°C were investigated. The results showed that the response of CO was improved obviously by doping 20mol%NiO or 5mol%CuO into the SnO2, while the response of H2 was changed no more, and the responses of CO and H2 both were enhanced dramatically by bearing 1mol%Pt into the SnO2. On the basis of empirical equation (R=1+kCn), two sensor cells with different selectivity were introduced to assemble a novel SnO2-based sensor, and proposed a potential method to detect the concentrations of CO and H2 in multi-component gases, in which the parameters of k and n for sensor cells were obtained and feasibility of the method was demonstrated.
Green Synthesis of Biopolymer-Silver Nanocomposites for Gas Sensing
Authors: Pande Shilpa A.
Published: October 2016

In this research work, a very simple, low cost eco-friendly method is presented for the synthesis of silver nanoparticles to be used in colorimetric optical sensors based on localized SPR (LSPR) measurement for gas ammonia. Silver nitrate salts are reduced using gaur gum which acts as a capping and reducing agent. Commonly used reducing agents such as trisodium citrate or sodium borohydride are replaced by a more environmental friendly natural polysaccharide. Nanocomposite films of ~ 1.5 μm thicknesses were fabricated using Gaur Gum and silver nanoparticles. The uniformity of nanoparticles size was measured by SEM and TEM, while face centred cubic structure of crystalline silver nanoparticles was characterized using the X-ray diffraction technique. The optical properties of the composite film were tested by UV-VIS Spectroscopy. The formation of Gaur Gum/silver nanocomposite films was confirmed using SEM images. Also the resistivity of nanocomposite thin film was measured which could be then used for gas sensing application.
Memory Loss in a Tantalum Oxide Memristor
Authors: Ascoli Alon , Tetzlaff Ronald , Chua Leon Ong , Strachan John Paul , Williams Richard Stanley
Published: October 2016

The tantalum oxide memristor may have a promising future as key element in innovativevery-high speed ultra-low power extra-large density nonvolatile memories. It is therefore timely andrelevant to investigate the nonlinear dynamics of this device in view of the interesting opportunities itmay open up in the world of electronics in the years to come. In numerical simulations of an accuratemodel of the tantalum oxide memristor manufactured at Hewlett Packard Labs we observed a surprisingphenomenon which was never reported earlier. Under AC periodic excitation the memristorexhibits unique asymptotic behaviour, irrespective of the initial condition. Thus the device may bestimulated in such a way to forget its past history. This memory erase effect, unexpected in a memristordevice, is closely related to the concept of fading memory from nonlinear system theory, and wasrecently confirmed through experiments conducted on a sample device.
Investigation of Solid State Diffusion Processes Involved in the Zinc Oxide Sulfidation Reaction
Authors: Perrin Kévin , Chiche David , Perez-Pellitero Javier , Politano Olivier , Chevalier Sébastien
Published: October 2016

Sulfidation of undoped and aluminum doped zinc oxide materials has been performed by TGA under a H2S atmosphere in order to evaluate the impact of the doping element on sulfidation reaction kinetics and mechanism. The presence of aluminum seems to slow-down the reaction kinetics. This phenomenon might be explained by a modification of the solid state diffusion processes involved in ZnO sulfidation reaction and the related ZnS outward growth, assuming the presence of aluminum atoms inside ZnO and ZnS phases. In order to determine solid state diffusion mechanisms controlling the reaction kinetics, molecular dynamics simulations were performed using a Coulomb-Buckingham potential. Firstly, the diffusion of the different elements (Zn, O, S) was simulated for both the oxide and sulfide phases considering a vacancy mechanism. Secondly, simulations of the oxide phase doped by a trivalent cation were also performed. The results obtained in this preliminary work are presented and compared to the literature.
Corrosion Behaviour of Equipment in High Temperatures and Corrosion Resistant Alloys
Authors: Fujikawa Hisao
Published: October 2016

Among the high temperature damages, this paper was discussed on the cases in which the materials were damaged mainly by the effect of environmental factors. That is, high temperature oxidation, steam oxidation, molten salt corrosion, high temperature particle erosion and corrosion, high temperature sulfurization, carburizing, metal dusting, nitriding, high temperature chloride corrosion and so on were introduced using my research data. Finally, anticipation to future research of high temperature corrosion was maintained.
An Overview on Silane Based Metal Pretreatments for Powder Painting
Authors: Özel Aslı , Çimenoğlu Hüseyin
Published: October 2016

This work provides an overview of organosilane metal pretreatments with a focus on water-based systems. Furthermore, this work aims to point out the key notes for organosilane technology to be fully transferred to industry.
Nanomaterials Applications in Modern Metallurgical Processes
Authors: Borodianskiy Konstantin , Zinigrad Michael
Published: October 2016

In recent years, improvement of metals mechanical properties becomes one of the main challenges in materials and particularly in metallurgical industry. Mostly, an alloying process is typically applied to reach metals enhanced performance. This work, however, describes a different methodology, where WC and TiC nanoparticles used as a modifiers and then gas-dynamic treatment (GDT) are applied. These processes were investigated on a hypoeutectic casting aluminum A356 alloy. Microstructural evaluation illustrated that a coarse Al grains were refined as well as eutectic Si particles were formed. Subsequent mechanical properties tests revealed that aluminum elongation enhanced while strength remained unchanged. Addition of WC and TiC enhanced the elongation by 20-60%, depends on the mold area. A combined treatment, using GDT with addition of TiCN nanoparticles showed even improvement in both, elongation and strength by 18 and 19%, respectively. Moreover, based on the electron microscopy studies, this behavior was attributed to a grain-size strengthening mechanism, where a high concentration of grain boundaries serves as dislocation movement blockers
Composition Variation on Bone Graft Synthesis Based on Hydroxyapatite and Alginate
Authors: Widiyanti Prihartini
Published: October 2016

Bone grafting is a surgical procedure that replaces missing bone with material from patient′s own body, an artificial, synthetic, or natural substitute. As natural bone grows, it generally replaces the graft material completely, resulting in a fully integrated region of new bone. The type of bone graft are allograft-based bone graft involves allograft bone, Factor-based bone graft are natural and recombinant growth , cell-based bone grafts, ceramic-based bone graft substitutes, polymer-based bone graft. The aim of study are to explore the influence of variations in the composition of alginate 8wt % , 10wt % , 12wt % to the characterization and the role of compacting pressure variation to the characterization of hydroxyapatite – alginate and to explore the best composition variation of alginate in which provides the best characteristics for application as a bone graft. All of the materials were mixed with a magnetic stirrer into liquid until homogeny, dried with oven with temperature of 50 °C, and then frozen for optimalizing the drying with sublimation method. The variation of Alginate composition were 8%wt, 10%wt, 12%wt, while the variation of compaction were 1 N/m2, 2 N/m2, 3 N/m2. The sample characterization used Fourrier Transform Infra Red (FTIR) test, compressive strength test, and MTT Assay test. Based on morphology assay, the pore sizes from samples with greater compaction force produces an increasingly smaller pore size. The result showed that variation of hydroxyapatite – alginate composition had effect to compressive strength value. The higher percentage composition of alginate, the greater pressure will increase the value of its compressive compaction and strength. The result of cytotoxicity test showed that nine samples were non toxic. In this research, the sample with composition 12% wt alginate and 3 N/ m2 in compaction was the best characteristic according to mechanical aspect.
The Effect of Y2O3 on Properties of Hydroxyapatite Thin Films Prepared by Pulsed Laser Deposition
Authors: Bao Quan He , Zhang Jie Qing
Published: October 2016

HA and HA+Y2O3 films were prepared by pulsed laser deposition. The microstructure and composition of films were studied by EPMA, XRD, AFM and SEM. In vitro study was performed by immersing the sample in simulate body fluid (SBF) in different days. There are more droplets on films prepared by HA+Y2O3 target than that of HA. And addition of Y2O3 can decrease the size of crystal grains. The XRD results show that the peaks corresponding to HA slightly shift to lower angel which indicates the HA lattice distorting due to addition of Y2O3. The critical load of the films increases from 10.3N to 13N when Y2O3 added. The film prepared by target HA+Y2O3 shows a higher resistance to dissolution and the precipitated grain size is small. New precipitated phases have similar functional groups with the original films.
A framework for the assessment and implementation of diagnostics in outbreak situations
Authors: Cowan Elliot P.
Published: October 2016

Observation: Outbreak situations require in vitro diagnostics (IVDs) to identify those who are infected and to track the infectious agent in the population. However, such IVDs are typically not available and must be developed. In addition, the process of IVD development, assessment, and implementation are very time and resource intensive. Recognising the extraordinary public health need for IVDs in an outbreak situation, streamlined processes are needed to provide tests that meet the standard of a reasonable assurance of safety and effectiveness in the shortest amount of time. These IVDs are designated for outbreak use.Addressing Issues: This paper presents a pathway to the outbreak use of IVDs that can be considered by countries experiencing an outbreak situation. It takes into account recognition of the outbreak, product development, regulatory evaluation, implementation, and monitoring of the outbreak-use test. Streamlined assessment programmes for emergency-use tests have been established by the US Food and Drug Administration and the World Health Organization. These programmes take into account test requirements for the country in which the outbreak exists. Therefore, countries can consider adopting these tests without the need to conduct expensive and time consuming assessments, such as performance studies. Key responsible parties are identified for each step of the pathway, recognising that transparency and communication among all parties are critical.
A new matrix for scoring the functionality of national laboratory networks in Africa: introducing the LABNET scorecard
Authors: Ondoa Pascale , Datema Tjeerd , Keita-Sow Mah-Sere , Oskam Linda , Ndihokubwayo Jean-Bosco , Isadore Jocelyn , Nkengasong John , Lewis Kim
Published: October 2016

Background: Functional national laboratory networks and systems are indispensable to the achievement of global health security targets according to the International Health Regulations. The lack of indicators to measure the functionality of national laboratory network has limited the efficiency of past and current interventions to enhance laboratory capacity in resourcelimited-settings.Scorecard for laboratory networks: We have developed a matrix for the assessment of national laboratory network functionality and progress thereof, with support from the African Society of Laboratory Medicine and the Association of Public Health Laboratories. The laboratory network (LABNET) scorecard was designed to: (1) Measure the status of nine overarching core capabilities of laboratory network required to achieve global health security targets, as recommended by the main normative standards; (2) Complement the World Health Organization joint external evaluation tool for the assessment of health system preparedness to International Health Regulations (2005) by providing detailed information on laboratory systems; and (3) Serve as a clear roadmap to guide the stepwise implementation of laboratory capability to prevent, detect and act upon infectious threats.Conclusions: The application of the LABNET scorecard under the coordination of the African Society of Laboratory Medicine and the Association of Public Health Laboratories could contribute to the design, monitoring and evaluation of upcoming Global Health Security Agenda-supported laboratory capacity building programmes in sub Saharan-Africa and other resource-limited settings, and inform the development of national laboratory policies and strategic plans. Endorsement by the World Health Organization Regional Office for Africa is foreseen.
Sierra Leone laboratory systems – now and future
Authors: Wurie Isatta
Published: October 2016

No abstract available.
Die mens geaffekteer deur kanker: Voorlopige bakens geidentifiseer met die oog op die prediking na aanleiding van Jesus se afskeidsgesprek in die Johannes-evangelie
Authors: Botha Darius
Published: October 2016

The life of a person affected by cancer becomes a confusion of emotions, experiences and tumultuous events. This takes place with immediate effect and can be summarised in one word ‘havoc’. The question that comes to mind in this article is: In which way can preaching guide the person affected by cancer, to equip this person to find both sense and meaning in this life. The farewell speech of Jesus in the Gospel of John will serve as departure for the stipulation of the beacons for the preaching in the guidance of the person affected with cancer. The aim of this article is firstly to show that the person affected by cancer has specific needs concerning preaching, secondly that the farewell speech of Jesus in the Gospel of John assists the preaching with certain beacons and thirdly to motivate that the metaphor of a ‘second’ is the most suitable for this kind of preaching. The purpose with this article is that the researcher wants to emphasise that the person affected by cancer can still experience sense and meaning in this life.
Atrial Electrophysiological Remodeling and Fibrillation in Heart Failure
Authors: Pandit Sandeep V. , Workman Antony J.
Published: October 2016

Heart failure (HF) causes complex, chronic changes in atrial structure and function, which can cause substantial electrophysiological remodeling and predispose the individual to atrial fibrillation (AF). Pharmacological treatments for preventing AF in patients with HF are limited. Improved understanding of the atrial electrical and ionic/molecular mechanisms that promote AF in these patients could lead to the identification of novel therapeutic targets. Animal models of HF have identified numerous changes in atrial ion currents, intracellular calcium handling, action potential waveform and conduction, as well as expression and signaling of associated proteins. These studies have shown that the pattern of electrophysiological remodeling likely depends on the duration of HF, the underlying cardiac pathology, and the species studied. In atrial myocytes and tissues obtained from patients with HF or left ventricular systolic dysfunction, the data on changes in ion currents and action potentials are largely equivocal, probably owing mainly to difficulties in controlling for the confounding influences of multiple variables, such as patient's age, sex, disease history, and drug treatments, as well as the technical challenges in obtaining such data. In this review, we provide a summary and comparison of the main animal and human electrophysiological studies to date, with the aim of highlighting the consistencies in some of the remodeling patterns, as well as identifying areas of contention and gaps in the knowledge, which warrant further investigation.
Accepting the Torch
Authors: Shalansky Stephen
Published: October 2016

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Accepter le flambeau
Authors: Shalansky Stephen
Published: October 2016

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Development and Implementation of an Antimicrobial Stewardship Program in a Rural Hospital
Authors: Hogan Kerry-Anne , Gazarin Mohamed , Lapenskie Julie
Published: October 2016

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Are Pharmacy Students Learning To Be Effective Collaborators and To Work within Health Care Teams through Our Interprofessional Education Initiatives?
Authors: Grymonpre Ruby , Paradis Elise
Published: October 2016

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Prevalence of Candida spp. in Healthy Oral Mucosa Surfaces with Higher Incidence of Chronic Hyperplastic Candidosis
Authors: Arruda Claúdia , Artico Gabriela , Freitas Roseli , Filho Antônio , Migliari Dante
Published: October 2016

Introduction

Predisposing factors in chronic hyperplastic candidosis (CHC) have been poorly recognized. This study aimed at assessing the prevalence of Candida spp. in areas of the oral mucosa showing greater prevalent rate of CHC, such as the retrocomissural area, the lateral borders of the tongue, and the hard-palate mucosa in four groups of individuals presenting predisposing factors as follows: Smoking habits (group I); patients with low salivary flow rate (SFR) (hyposalivation – group II); patients with loss of vertical dimension of occlusion (LVDO – group III); and control subjects (group IV).

Materials and methods

A total of 44 individuals (age 40–90 years, mean: 55.8 years) were divided into four groups: Group I (11 smokers); group II (10 hyposalivation patients); group III (10 LVDO patients); and group IV (control, 13 healthy subjects). All individuals were tested for Candida-pseudohyphae form by direct examination and for Candida spp. culture growth in samples obtained from the retrocomissural, tongue's lateral border, and hard–soft palatal mucosa.

Results

Direct examination showed a statistically significant prevalence rate for pseudohyphae (p < 0.05) on the retrocomissural and on tongue's lateral borders of individuals with LVDO. A statistically significant (p < 0.05) culture growth for Candida spp. was found on the retrocomissural areas of those with hyposalivation and with LVDO, and on the palate mucosa and on the tongue's lateral borders in the smokers and in the individuals with LVDO when compared with those of the control group.

Conclusion

While direct examination is effective for detecting pseudohyphae, LVDO and tobacco smoking seem to be factors of relevance to the development of CHC.

Clinical significance

Since CHC has been linked to a high rate of malignant transformation, this study analyzes some clinical (and exogenous) factors that may contribute to the development of CHC and addresses some preventive measures to reduce its incidence.

How to cite this article

Arruda C, Artico G, Freitas R, Filho A, Migliari D. Prevalence of Candida spp. in Healthy Oral Mucosa Surfaces with Higher Incidence of Chronic Hyperplastic Candidosis. J Contemp Dent Pract 2016;17(8):618-622.
Remineralizing Effect of Topical NovaMin and Nanohydroxyapatite on Caries-like Lesions in Primary Teeth
Authors: Haghgoo Roza , Ahmadvand Motahare , Moshaverinia Sareh
Published: October 2016

Introduction

NovaMin is a synthetic mineral compound composed of calcium, sodium, phosphorus, and silica. It releases crystalline hydroxyl-carbonate apatite (HCA), which structurally resembles the minerals naturally found in the teeth. Nanohydroxyapatite (NHA) is a biocompatible compound with high affinity for tooth enamel. NHA particles morphologically resemble dental enamel apatite crystals. Considering the efficacy of remineralizing agents and the importance of conservative preventive measures, this study aimed to compare the remineralizing effects of NovaMin and NHA on caries-like lesions in primary teeth.

Materials and methods

This in vitro experimental study was conducted on 30 sound human primary anterior teeth with no cracks or fractures. The surface microhardness (SMH) of each tooth was measured at baseline using a Vickers microhardness tester. The teeth were then subjected to remineralization/ demineralization cycles, and artificial caries lesions were created in them. The SMH of each tooth was measured again and the teeth were then randomly treated with toothpastes containing NovaMin or 10% NHA powder for 2 minutes daily for a period of 5 days. The SMH of each was again measured afterward. Data were statistically analyzed using independent t-tests and Mann–Whitney U tests.

Results

The mean SMH was found to be higher in the teeth treated with NovaMin toothpaste (422.67 kgf/mm2) than in the teeth treated with NHA (384.2 kgf/mm2); However, this difference was not statistically significant.

Conclusion

Both NHA and NovaMin were effective for remineralization of caries-like lesions of primary teeth and no significant difference was detected in their efficacy.

How to cite this article

Haghgoo R, Ahmadvand M, Moshaverinia S. Remineralizing Effect of Topical NovaMin and Nano-hydroxyapatite on Caries-like Lesions in Primary Teeth. J Contemp Dent Pract 2016;17(8):645-649.