bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of Electrophoretic Deposition Kinetics for Preparation of Laminated Alumina/Zirconia Ceramic Composites
Authors: Hadraba Hynek , Drdlík Daniel , Chlup Zdeněk , Maca Karel , Dlouhý Ivo
Published: March 2012

Electrophoretic deposition of Al2O3 and ZrO2 powders from isopropanol suspension in the presence of monochloroacetic acid under constant-current conditions was studied. The deposits were prepared under different electrical conditions of deposition. It was found that the deposits prepared at low current densities (500 µA) contained smaller pores and achieved higher green densities than deposits prepared at high current densities (20 mA). The deposits prepared at low current densities were formed just by part of the particles in the suspension because of decreasing of efficiency of electrophoretic deposition process.
Development of Diffusion Barrier Coatings for Mitigation of Fuel-Cladding Chemical Interactions
Authors: Firouzdor Vahid , Wilson Lucas , Sridharan Kumar , Semerau Brandon , Hauch Benjamin , Brechtl Jamieson , Cole James I. , Allen Todd R.
Published: March 2012

Fuel Cladding Chemical Interactions (FCCI) in a nuclear reactor occur due to thermal and radiation enhanced inter-diffusion between the cladding and fuel materials, and can have the detrimental effects of reducing the effective cladding wall thickness and the formation of low melting point eutectic compounds. Deposition of diffusion barrier coatings of a thin oxide on the inner surface of the cladding can potentially reduce or delay the onset of FCCI. This study examines the feasibility of using nanofluid-based electrophoretic deposition (EPD) process to deposit coatings of titanium oxide, yttria-stabilized zirconia (YSZ) and vanadium oxide. The deposition parameters, including the nanofluid composition, current, and voltage were optimized for each coating material using test flat substrates of T91 ferritic-martensitic steel. Diffusion characteristics of the coatings were investigated by diffusion couple experiments using the fuel surrogate cerium. These diffusion couple studies performed in the temperature range of 560°C and 585°C showed that the oxide coatings significantly reduce the solid state inter-diffusion between cerium to steel.
High Voltage Electrophoretic Deposition of Aligned Nanoforests for Scalable Nanomanufacturing of Electrochemical Energy Storage Devices
Authors: Santhanagopalan Sunand , Balram Anirudh , Lucas Evan , Marcano Franco , Meng Dennis De Sheng
Published: March 2012

High voltage electrophoretic deposition (HVEPD) has been used to obtain forests of aligned multi-walled carbon nanotubes (MWCNTs) on long strips of flexible, conductive substrates. Successful design and integration of a continuous HVEPD setup has enabled scalable fabrication of electrodes for electrochemical energy storage. The mechanism of continuous HVEPD has been investigated to ensure appropriate alignment. Well-aligned forests of MWCNTs were obtained using a conductive holding layer which helped reduce internal resistance and enhance the electrochemical performance of the electrodes.
Numerical Analysis of the Stress/Strain Evolution in Incremental Sheet Forming and Stretch-Bending Processes
Authors: Centeno G. , Vallellano C. , Vázquez J. , Doblas F.J. , Martínez-Donaire A.J. , García-Lomas F.J.
Published: March 2012

In this paper, the evolution of plastic strain and hydrostatic pressure evolutions in incremental sheet forming (ISF) processes to postpone fracture of the metal sheet is analyzed. A finite element (FE) model of an incremental forming operation and a conventional stretch-bending operation is performed. Experimental results of stretching tests are used as reference. The local evolution of the straining and the distribution of hydrostatic pressure are studied in detail. Different step downs and friction coefficients are simulated and their results are discussed.
Study of the Proper Sintering Conditions of Anionically-Polymerized Polyamide 6 Matrices for the Fabrication of Greencomposites
Authors: Alfonso A. , Andrés J. , García J.A.
Published: March 2012

The present research work assesses the manufacture of long fiber thermoplastic matrix composite materials (GreenComposites). Thermoplastic matrices are too viscous to be injected into the conventional LCM (Liquid Composite Molding) molds, and then epoxy, polyester or vinylester resins are used. Nevertheless, the groundbreaking anionic polymerization of caprolactam allows such a synthesis of a thermoplastic APA6 matrix inside the mold. This matrix is sintered from the starting monomers, and presents high mechanical performance and recyclability. In order to do the reactive injection in a LCM mold, it is necessary to control the polymerization mechanism of such a thermoplastic matrix. This paper puts special emphasis on detecting and solving all problems which arose during synthesis. For instance, moisture values were assessed for all starting reactants, since humidity keeps polymerization from occurring. It is thought that once the synthesis and the resulting material characterization are well controlled, the manufacture of GreenComposites through in situ polymerization, as well as addition of state-of-the-art fabrics such as basalt, can proceed successfully.
Surface Topography Prediction on Laser Processed Tool Steel
Authors: Ukar Eneko , Lamikiz Aitzol , Martínez S. , López de Lacalle Luis Norberto
Published: March 2012

In laser surface treatment the laser beam is used as energy source for surface modification improving aspects such as mechanical properties, tribology or surface texture. Modeling tools have special interest in processes with many variables, like laser surface processing, in order to minimize the tryout testing to find the optimal process parameters. The work presented here focuses on the prediction of the final topography in laser polishing process. By FFT analysis of the surface profile it is possible to get the different frequency components of the initial topography. On the other hand, thermal field simulation was carried out to evaluate the melt duration. Matching this with the spatial frequency damping during process, the reconstruction of the processed topography was obtained.
Analytical Approach to the Indentation Process. Application of the Upper Bound Element Technique
Authors: Martín F. , Sevilla L. , Bermudo C.
Published: March 2012

Present work poses, from the methodological point of view, an approach to a case offorging by indentation by means of the application of the Upper Bound Element Technique(UBET), in his development of triangular rigid blocks (TRB). With two approaches of differentnature (Modulate and not Modulate), it tackles the study of the evolution of the necessary minimumenergy to attain the required deformation. The UBET allows a suitable implementation of theboundary conditions of the process, as well as the characteristic of the same, such as the kind offriction or the geometrical considerations, without limit on the flow of material in contrary directionto the applied load by the tool.
Current Research Trends in Abrasive Waterjet Machining of Fiber Reinforced Composites
Authors: Kalla D.K. , Zhang B. , Asmatulu R. , Dhanasekaran P.S.
Published: March 2012

The use of fiber reinforced polymer (FRP) composites in the aircraft and automotive industries exponentially. Reinforced fibers which are abrasive in nature make it hard to machine by the traditional machining. Dissipation of heat into workpiece which in turn results in enhanced cutting tool wear and damage to the workpiece is the common problems faced in traditional machining of FRPs. Nontraditional machining is favorable to reduce these issues. Abrasive waterjet machining (AWJM) is one of the best choices for machining FRPs. Development in AWJM of FRPs and the current research in this field will be discussed in details. Machining process of FRPs, quality dependents such as surface finish and variable cutting parameters will be addressed. One of main issues in AWJM noise due to high flow rate of water jet will be addressed. The importance of human safety aspects when AWJM is employed will be highlighted. Limitations and challenges in AWJM are presented elaborately.
Effect of Electrolyte on the Surface Smoothness Obtained by Electropolishing of Stainless Steel
Authors: Hernando M. , Núñez López Pedro Jose , García Plaza Eustaquio , Trujillo R.
Published: March 2012

Electropolishing is a surface finishing process of metals and alloys that enhances brilliant surface finishes with low surface roughness values. The most widely used electrolytes for the electropolishing of stainless steel are varying concentrations of phosphoric and sulphuric acid, and occasionally additives such as chromic acid. The objective of this study was to assess the performance of three commonly used industrial electrolytes in terms of the surface finish of electropolished stainless steel AISI 316L. Each electrolyte had varying sulphuric-phosphoric acid combinations with or without chromic acid. The following electropolishing conditions were assessed: current density, bath temperature, electropolishing time, and initial surface texture. The results revealed that adding chromic acid to the electrolyte did not significantly enhance surface finish, and electropolishing ranges were quite similar for all three electrolytes.
New Technologies for Increasing the Capacities of WEDM Machines
Authors: Sánchez Jose Antonio , Plaza Soraya , Ramos J.M. , Izquierdo B. , Ortega N. , Pombo I.
Published: March 2012

The process of Wire Electrical Discharge Machining (WEDM) has experienced a dramatic growth in the last years. Together with the new requirements imposed by customer needs, globalization of the markets has brought about a new scenario in which competitiveness is the keyword. In the case of WEDM, it is only possible from a perspective that integrates developments in hardware, software and know-how, to generate the required added-value with respect to competitors. For instance, it is not enough to give an answer to the demand of a high-speed first cut: economy must be achieved together with a high accuracy and using low-cost wires. In this paper the research actions currently running aiming at the development of a new generation of WEDM machines are presented. The objective of this paper is to present an integrated research approach focused on industrial needs, covering the following aspects: Accuracy and productivity; automation and machine intelligence; eco-efficiency.
Methods of Electron Crystallography as Tools for Materials Analysis
Authors: Neumann Wolfgang , Kirmse Holm , Häusler Ines , Grosse Corinna , Moeck Peter , Rouvimov Sergei , Beekman Matt , Atkins Ryan , Johnson David C. , Volz Kerstin
Published: March 2012

Abstract. New methods of electron crystallography, particularly modern methods of electron diffraction have opened new strategies for the structure analysis of nanostructured materials and materials systems. The possibilities and limitations of the combined use of electron crystallography methods will be demonstrated for a semi-automatic orientation determination of MnAs clusters in a GaAs matrix and structural investigations of ferecrystals.
Microstructure of LaNi5 Base Nanopowders Produced by High Energy Ball Milling
Authors: Kusiński Jan , Kowalski K. , Kac Sławomir , Matteazzi P. , Krebs M. , Morgiel Jerzy , Cochet S.
Published: March 2012

LaNi5 nano-powders with additions of Ce, Mn, Co (high and low content of cobalt) and Al were obtained by means of MBN technology, based on the high energy ball milling with different energy and protective atmosphere (Ar or H2). The microstructure and composition of all prepared nano-powders were investigated using the TEM/HRTEM, SEM/EDS, XRD and XPS techniques. Research showed that used technology allowed to produce materials distinguished by a fine and homogeneous chemical distribution of elements and an "ultrafine" (the nanometric size) crystalline structure. The results were then related to the preparation conditions.
The Art and Application of Large Angle Convergent Beam Electron Diffraction
Authors: Jezierska Elżbieta
Published: March 2012

The antiphase domain structure in Ni3Al and Al3Ti+Cu intermetallic alloys was recognized by conventional transmission electron microscopy and large angle convergent beam electron diffraction methods. In the case of antiphase boundary the superlattice excess line is split into two lines with equal intensity on bright and dark field LACBED pattern. This splitting can be considered as typical and used to identify APBs. The recognition between perfect structure of the defect-free matrix and the screw deviation around the nanopipes in GaN epilayers was performed with high accuracy using Zone Axis LACBED images.
Structure and Morphology of Thin Films Deposited by Pulsed Laser Deposition Technique
Authors: Radziszewska Agnieszka
Published: March 2012

The paper presented the structure (TEM), morphology and chemical composition (EDS) of the -Al-Mg thin films and Al-Mg-Ni multilayer obtained by pulsed laser deposition (PLD). This films were deposited using Nd:YAG laser. The different process parameters were applied. The Al-Mg film was obtained by application of the laser wavelength (=355 nm) and substrate temperature (Ts) 200 oC. Whereas the Al-Mg-Ni multilayer was produced at lower laser wavelength (=266 nm) and at room temperature of the substrate. For preparation of both films the same laser fluence (q=4.7 J/cm2) was used. The Al-Mg possessed nanocrystalline structure with the areas where only columnar Al crystals occurred. EDS of this thin film exhibited that in the nanocrystalline areas the chemical composition corresponded to the target content of Al and Mg. While Al-Mg-Ni multilayer composed of six layers. In this case Al-Mg layers were thinner then Ni layers. In the multilayer structure the fcc Al0.65Mg0.35 and fcc Ni phases was revealed.
Electron Microscope Investigation of PVD Coated Aluminium Alloy Surface Layer
Authors: Tański Tomasz , Labisz Krzysztof
Published: March 2012

The purpose of this work is electron microscope investigation of the Ti/TiCN/TiAlN and Cr/CrN/CrN coatings deposited by PVD process. The investigations were performed using scanning and transmission electron microscopy for the microstructure determination. By mind of the transmission electron microscopy the high resolution and phase determination was possible to obtain. The morphology was studied as well the lattice parameters for the layer matrix and substrate phase identification using diffraction methods was applied. After the coating of the aluminium alloys AlSi9Cu and AlSi9Cu4 with the selected coatings there are crystallites detected with the size of several tenth of diameter. The investigated samples were examined metallographically using electron microscope with different image techniques, also EDS microanalysis and electron diffraction was made. As an implication for the practice a new layer sequence can be possible to develop, based on PVD technique. Some other investigation should be performed in the future, but the knowledge found in this research shows an interesting investigation direction. The originality and value of this combination of TEM investigation for PVD deposited surface lasers on aluminium alloys makes the investigation very attractive for automotive and other industry branches. Some practical implications and employment of the surface treatment technology for elements, made from tool materials, with the PVD and CVD methods, to obtain the high wear resistant coatings, makes it possible to improve the properties of these materials by – among others – decreasing for example their friction coefficient, microhardness increase, improvement of the tribological contact conditions in practical use. One original value is it also to applied the PVD method on a common material like aluminium alloy. The double layer coatings worked out In the PVD process on the Al0Si-Cu alloys substrate hale the following configuration of the layers: bottom layer/gradient layer/wear resistant hard surface layer.
Optimization of Structure and Magnetic Properties of NdFeBTi Nanocomposite Magnets
Authors: Derewnicka Daniela , Dłużewski Piotr , Spyra Marzena , Krztoń Hanna
Published: March 2012

This study investigated alloys with the composition Nd9Fe77B14 and Nd9Fe73Ti4B14 (at.%). Materials were melt spun in the form of a partially amorphous ribbon, which was subsequently annealed at 953K in order to obtain the optimum magnetic properties. The highest properties were obtained for annealing lasting 20 minutes (JHC = 913kA/m, Jr = 0,84T, BHmax = 107kJ/m3). Annealing at 953K results in simultaneous crystallisation in the whole mass of the alloy. The growth of grains is controlled by the duration of the annealing process. The objective of this work was to study the mechanisms of crystallisation and the reasons for a finer structure resulting from the presence of titanium. The phase composition was evaluated by X-ray diffraction. The microstructure was studied using a high-resolution transmission electron microscope. Detailed analysis of titanium distribution in the grains and in the grain boundaries was examined by x-ray spectrometry.
SEM and TEM Characterization of NiAl2O4 Spinel Phase in Al2O3 Matrix Ni Composite
Authors: Konopka Katarzyna , Lityńska-Dobrzyńska Lidia , Dutkiewicz Jan
Published: March 2012

The microstructure and crystallographic relationship development of spinel phase of the composite prepared by sintering of Al2O3 and Ni powders below the melting point of Ni was investigated. Spinel phase is distributed not uniformly and the outer region of sample contains Al2O3 and NiAl2O4 without Ni particles. The differences in the microstructure between the central and surface part of the sample was clearly demonstrated. In the central part of the sample this process was only initiated and start of this reaction can be observed at the Ni/Al2O3 interface. This distribution of spinel phase is connected with the process of its formation and stability. Analysis of the crystallographic relationship between the Ni and spinel (S) indicates that the most common is the crystallographic relationship [001] S || [001] Ni or [001] S || [111] Ni. Similarly there is some statistical preference of the crystallographic relationship between spinel and Al2O3. In this case more often observed relationship is [100] S || [111] Al2O3, however similarly as in the case of Ni some deviations of several degrees are also frequent.
SEM and TEM Studies of Magnetic Shape Memory NiCoMnIn Melt Spun Ribbons
Authors: Maziarz Wojciech
Published: March 2012

Microstructure of Ni50-xCoxMn35.5In14.5 (x=0, 3, 5) melt-spun ribbons was investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The typical layered microstructure consisting of oriented columnar grains and colonies of fine equi-axed grains was observed in the cross section of ribbons. The crystallographic structure of ribbons varied with the content of Co in alloys what affected of their Ms temperature. For the x=0 the single phase of monoclinic 14M modulated martensite was observed, but for x=3 and 5, a two phase structure of L21 austenite and monoclinic 14M or orthorhombic 10M modulated martensite were identified. Different temperature range of martensitic transformations were explained basing on valence electron concentration per atom e/a versus Ms relationship.
Structure of Nitride and Nitride/Oxide Layers Formed on NiTi Alloy
Authors: Lelątko Józef , Freitag Marlena , Rak Jan , Wierzchoń Tadeusz , Goryczka Tomasz
Published: March 2012

The present work summarises the results, which were obtained from studies carried out on the structure of the nitride and nitride-oxide surface layers with use of the electron transmission microscopy. The layers were formed using glow discharge technique at relatively low temperature (300°C). It has been shown that low temperature nitriding or nitriding/oxiding process produced a thin layer ~30 nm thick. They were formed from titanium nitride as well as titanium oxides. The structure revealed that nanoparticles were surrounded by high amount of amorphous phase. Especially, electron microscopy was useful method for studying the phase boundary between the layer and the NiTi matrix. During deposition process, which was carried out at temperature above 300°C, the intermediate layer of Ni3Ti intermetallic phase appeared between titanium oxides and/or nitrides. Lowering deposition temperature down to 300°C or below resulted in absence of such sublayer. Moreover, thickness, structure of layers, absence of sublayer formed during glow discharge process, can significantly influence deformation during inducing of the shape memory or superelasticity effect.
Positive Hydrogen Effect in Structure Surface Layers on Ti Alloy
Authors: Sozańska Maria , Garbacz Halina
Published: March 2012

This paper presents the influence hydrogen effect in structure of surface layers on Ti-6Al-4V two-phase titanium alloys. It was described that hydrogen can be used as a temporary alloying element.The paper regarding the HTM - Hydrogen Treatment of Materials as an attractive method for controlling structure and improving final mechanical properties of titanium alloys. Hydrogen treatment consists of the three stages: hydrogenation in hydrogen gas atmosphere (600°C), cyclic heat hydrogen treatment (250°C), dehydrogenation in vacuum (550°C). This treatment uses purposeful, temporary introduction of hydrogen into the alloy to generate defects in its microstructure. Furthermore, it then causes recrystallization of defect microstructure during the dehydrogenation stage to grain refinement. This high-temperature treatment is very efficient for changing the microstructure and mechanical properties of two-phase titanium alloys.
A Quantitative Analytical Method for the Identification and Characterization of Mineralized Nanoparticles in Food Supplements
Authors: Richter Susanne , Riediger Klaus , Nester Angelika
Published: March 2012

Food supplements play an increasing role in the nanofood market because improvement of effectiveness and efficiency of delivery of bioactive compounds is presumed. An electron microscopic method based on the international Standard ISO 13322-1:2004 was developed for controlling and documenting size, size distribution, surface structure, shape and aggregation state of mineralized food supplement particles. For particle size distribution, a combination of conventional TEM- and SEM-methods, which allows identifying the size distribution of the whole product, is described.
Physical and Chemical Studies of Bacterial Bioaerosols at Wastewater Treatment Plant Using Scanning Electron Mikroscopy and X-Ray Photoelectron Spectroscopy
Authors: Płoszaj Justyna , Talik Ewa , Piotrowska-Seget Zofia , Pastuszka Józef S.
Published: March 2012

The paper presents the research results of the airborne bacteria collected at the wastewater treatment plants working with activated sludge system. Samples were taken by a six-stage Andersen Impactor placed near the aeration chambers. Bacteria cought at Petri plates were incubated at room temperature for 4 days, then analyzed in a macroscopic and microscopic way. This initial investigation was aimed at morphological characteristics of colonies and breeding characteristics of particular strains to giver general overwiev. Bacteria were identified on the basis of their metabolic properties using API biochemical tests. The essential studies were carried out using JOEL scanning electron microscope (FE-SEM model with field gun 7600[F]), equipped with "Cryo-SEM”, which gives the possibility of testing delicate biological samples in a frozen state. Its high resolving power and large depth of field allows to obtain images of surface structure of microorganisms in a magnification range from 1 000x to 70 000x. Bacteria samples were analyzed also in a fructured state what revealed internal structes and the thickness of cell walls which was in the range of 0,080-0,180 [μm]. Moreover, elemental composition of the surface layer of bacterial was also examined using photoelectron spectroscopy (XPS). Dominant elements were carbon, oxygen and nitrogen. Analysis of main line (C1s, O1s, N1s) allowed the identification of chemical composition of studied bioaerosols. Investigation found that the main compounds were polymers such as peptides and polysaccharides, as well hydrocarbon like compounds.
Structural and Chemical Characterization of Al(Ga)N/GaN Quantum Well Structures Grown by Plasma Assisted Molecular Beam Epitaxy
Authors: Borysiuk Jolanta , Dłużewski Piotr , Zytkiewicz Zbigniew , Sobańska Marta , Kłosek Kamil , Łucznik Bolesław
Published: March 2012

Growth of high quality GaN/AlN heterostructures by plasma assisted molecular beam epitaxy (PAMBE) is possible with excess of Ga on the surface. During growth of AlN this additional Ga acts as surfactant and improves mobility of the Al adatoms on the growing surface, at the possible cost of Ga segregation and creation of mixed AlGaN interlayer. Scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) were used to determine chemical composition of high crystallographic quality GaN-AlN multilayer structure. It was shown that segregation occurs at AlN-GaN heterointerfaces, while GaN-AlN interfaces have abrupt stepwise change of the chemical composition. HRTEM results show creation of trench defects at the periphery of growing AlN islands in the case of nonoptimized growth.
SEM EBSD and TEM Structure Studies of α-Brass after Severe Plastic Deformation Using Equal Channel Rolling Followed by Groove Pressing
Authors: Rusz Stanislav , Dutkiewicz Jan , Faryna Marek , Maziarz Wojciech , Rogal Lukasz , Bogucka Joanna , Malanik Karel , Kedroň Jan , Tylšar Stanislav
Published: March 2012

Commercial brass Ms36, 2mm thick was annealed and deformed in 6 passes in dual rolls equipment with attached equal channel equipment (DRECE). Then, material was deformed again using constrained groove pressing (CGP) by pressing of grooves 4.2 mm thick, and the groove angle of 45 deg. The experiment was performed 8 times (pressing out grooves and straightening at room temperature). Both methods allowed deformation without changing of the thickness of the sample, which was almost constant near 2 mm. The tensile experiment have shown the Yield Strength YS after 8x groove pressing of 210 MPa and Ultimate Tensile Strength UTS increased 27% up to 430 MPa. At the same time total elongation decreased from 34 to 15 %. The structure of the material after DRECE 6 passes was investigated using conventional TEM and have shown only rather uniform distribution of dislocations. After additional 8 groove pressing experiment, frequent, narrow deformation twins were observed accompanied by the formation of subgrains. Orientation imaging microscopy performed have shown average grain size after DRECE process near 5 μm, which decreased after 8 processes of groove pressing down to 2.9 μm. The fraction of low angle boundaries (below 5 deg) decreased after groove pressing down to 73% from 85% after DRECE process and annealing, while the fraction of high angle grain boundaries (>15 deg) increased after groove pressing up to 24% from 14%, however the total length of high angle boundaries increased more than 2 times since grain size decreased. The structure studies have shown rather mild effect on the grain refinement of both methods and they have to be modified to obtain material approaching nanosize range.
Morphology of Axymyia furcata (Diptera: Axymyiidae), including scanning electron microscopy of all life stages
Authors: Wihlm Matthew W. , Sam Rebecca B. , Courtney Gregory W.
Published: March 2012

The morphology of all life stages of the semi-aquatic nematocerous fly, Axymyia furcata McAtee (Diptera: Axymyiidae), is documented, with emphasis on use of scanning electron microscopy (SEM). Our data on some life stages (e.g., egg, first-instar larvae) represent the first SEM examination of these stages in axymyiids. Among the unexpected results is absence of an egg burster in first instars. Most characters provided little evidence of a phylogenetic relationship with any other clade of nematocerous Diptera, reflecting a need for comprehensive morphological studies of the immatures of many families.
Pleiotropic IFN-Dependent and -Independent Effects of IRF5 on the Pathogenesis of Experimental Lupus
Authors: Xu Yuan , Lee Pui Y. , Li Yi , Liu Chao , Zhuang Haoyang , Han Shuhong , Nacionales Dina C. , Weinstein Jason , Mathews Clayton E. , Moldawer Lyle L. , Li Shi-Wu , Satoh Minoru , Yang Li-Jun , Reeves Westley H.
Published: March 2012

Genetic polymorphisms of IFN regulatory factor 5 (IRF5) are associated with an increased risk of lupus in humans. In this study, we examined the role of IRF5 in the pathogenesis of pristane-induced lupus in mice. The pathological response to pristane in IRF5−/− mice shared many features with type I IFN receptor (IFNAR)−/− and TLR7−/− mice: production of anti-Sm/RNP autoantibodies, glomerulonephritis, generation of Ly6Chi monocytes, and IFN-I production all were greatly attenuated. Lymphocyte activation following pristane injection was greatly diminished in IRF5−/− mice, and Th cell differentiation was deviated from Th1 in wild-type mice toward Th2 in IRF5−/− mice. Th cell development was skewed similarly in TLR7−/− or IFNAR−/− mice, suggesting that IRF5 alters T cell activation and differentiation by affecting cytokine production. Indeed, production of IFN-I, IL-12, and IL-23 in response to pristane was markedly decreased, whereas IL-4 increased. Unexpectedly, plasmacytoid dendritic cells (pDC) were not recruited to the site of inflammation in IRF5−/− or MyD88−/− mice, but were recruited normally in IFNAR−/− and TLR7−/− mice. In striking contrast to wild-type mice, pristane did not stimulate local expression of CCL19 and CCL21 in IRF5−/− mice, suggesting that IRF5 regulates chemokine-mediated pDC migration independently of its effects on IFN-I. Collectively, these data indicate that altered production of IFN-I and other cytokines in IRF5−/− mice prevents pristane from inducing lupus pathology by broadly affecting T and B lymphocyte activation/differentiation. Additionally, we uncovered a new, IFN-I–independent role of IRF5 in regulating chemokines involved in the homing of pDCs and certain lymphocyte subsets.
EPIDEMIOLOGY, DIAGNOSIS AND TREATMENT OF ACUTE PROMYELOCYTIC LEUKEMIA IN CHILDREN: THE EXPERIENCE IN CHINA
Authors: Zhang Li , Zhu Xiaofan
Published: March 2012

The limited available data suggest that the rate of early mortality is high and that long-term survival is poor in many developing countries. Death from bleeding and infection during chemotherapy, relapse and treatment abandonment are among the main cause of treatment failure in APL children. The status of children APL treatment in China is not described in general.
Adjuvant corticosteroid therapy in hepatosplenic candidiasis-related IRIS
Authors: Bayram Cengiz , Fettah Ali , Yarali Nese , Kara Abdurrahman , Azik Fatih Mehmet , Tavil Betül , Tunc Bahattin
Published: March 2012

Hepatosplenic candidiasis (HSC) is a form of invasive fungal infection that occurs most commonly in patients with acute leukemia treated with chemotherapy and requires protracted antifungal therapy. Immune reconstitution inflammatory syndrome (IRIS) is best characterized as a dysregulated inflammatory responses triggered by rapid resolution of immunosuppression.We present a child diagnosed with standard-risk precursor B cell-acute lymphoblastic leukemia who developed HSC and Candida-related IRIS during recovery of neutropenia associated with induction chemotherapy. Addition of corticosteroid therapy to antifungal treatment is associated with the resolution of the clinical symptoms and laboratory findings
Comparison of microbial community structures in four Black soils along a climatic gradient in northeast China
Authors: Mi Liang , Wang Guanghua , Jin Jian , Sui Yueyu , Liu Judong , Liu Xiaobing
Published: March 2012

Mi, L., Wang, G., Jin, J., Sui, Y., Liu, J. and Liu, X. 2012. Comparison of microbial community structures in four Black soils along a climatic gradient in northeast China. Can. J. Soil Sci. 92: 543–549. Surveys of microorganisms across climatic gradients provide important information about their biodiversity and spatial distribution, which is linked to fundamental ecological functions. The present study investigated the bacterial communities, including total and culturable communities, and fungal communities in Black soils collected from Lishu (lat. 43°20′N, long. 124°28′E), Dehui (lat. 44°12′N, long. 125°33′E), Hailun (lat. 47°26′N, long. 126°38′E) and Beian (lat. 48°17′N, long. 127°15′E) in northeast China. Bacterial and fungal communities were evaluated by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) banding patterns of partial 16S rDNA and fungal rDNA internal transcribed spacer regions (ITS), respectively. Bacterial and fungal diversity, based on the number of DGGE bands, were similar among the locations, but cluster analysis of banding patterns showed distinct microbial communities along the climatic gradient. A closer relationship was found among soil bacterial (total and culturable) and fungal communities in neighboring locations than those at greater distance, which suggested that the spatial distribution of microbial community existed in the Black Soil Zone. Comparison of DGGE profiles among the four locations showed that the changes of fungal community and culturable bacterial community were greater than that of bacterial community, suggesting that fungal community and culturable bacterial community are more suitable to study microbial biogeographic distribution in Black soils.
Occupation: Purposefulness and Meaningfulness as Therapeutic Mechanisms
Authors: Trombly Catherine A.
Published: March 2012

The model of occupational functioning leads the author to conceptualize occupation both as treatment end goal and as means to remediate impairments. In both dimensions, meaningfulness and purposefulness are key therapeutic qualities. Purposefulness is hypothesized to organize behavior and meaningfulness to motivate performance. These aspects of occupation need explication through research. Some questions that need to be answered include the following: How does purposefulness of occupation-as-end organize a person’s life? Does purposefulness of occupation-as-means organize particular behavioral responses? What effect does meaningfulness of occupation-as-end have on achievement of role performance? Does meaningfulness of occupation-as-means motivate perseverance and effort during therapy?
Contribution of flowering trees to urban atmospheric biogenic volatile organic compound emissions
Authors: Baghi R. , Helmig D. , Guenther A. , Duhl T. , Daly R.
Published: March 2012

Abstract. Emissions of biogenic volatile organic compounds (BVOC) from urban trees during and after blooming were measured during spring and early summer 2009 in Boulder, Colorado. Air samples were collected onto solid adsorbent cartridges from branch enclosures on the tree species crabapple, horse chestnut, honey locust, and hawthorn. These species constitute ~65 % of the insect-pollinated fraction of the flowering tree canopy (excluding catkin-producing trees) from the street area managed by the City of Boulder. Samples were analyzed for C10–C15 BVOC by thermal desorption and gas chromatography coupled to a flame ionization detector and a mass spectrometer (GC/FID/MS). Identified emissions and emission rates from these four tree species during the flowering phase were found to vary over a wide range. Monoterpene emissions were identified for honey locust, horse chestnut and hawthorn. Sesquiterpene emissions were observed in horse chestnut and hawthorn samples. Crabapple flowers were found to emit significant amounts of benzyl alcohol and benzaldehyde. Floral BVOC emissions increased with temperature, generally exhibiting exponential temperature dependence. Changes in BVOC speciation during and after the flowering period were observed for every tree studied. Emission rates were significantly higher during the blooming compared to the vegetative state for crabapple and honey locust. Total normalized (30 °C) monoterpene emissions from honey locust were higher during flowering (5.26 μg Cg−1 h−1) than after flowering (1.23 μg Cg−1 h−1). The total normalized BVOC emission rate from crabapple (93 μg Cg−1 h−1) during the flowering period is of the same order as isoprene emissions from oak trees, which are among the highest BVOC emissions observed from plants to date. These findings illustrate that during the relatively brief springtime flowering period, floral emissions constitute by far the most significant contribution to the BVOC flux from these tree species, some of which are leafless at this time. Experimental results were integrated into the MEGAN biogenic emission model and simulations were performed to estimate the contribution of floral BVOC emissions to the total urban BVOC flux during the spring flowering period. The floral BVOC emitted during this three-month simulation are equivalent to 11 % of the cumulative monoterpene flux for the Boulder urban area.
Observations of widespread accelerated thinning in the upper reaches of Svalbard glaciers
Authors: James T. D. , Murray T. , Barrand N. E. , Sykes H. J. , Fox A. J. , King M. A.
Published: March 2012

Abstract. The measured rise in eustatic sea level over the 20th century was dominated by mass loss from the world's mountain glaciers and ice caps, and predictions suggest that these fresh water reservoirs will remain significant into the 21st century. However, estimates of this mass transfer to the ocean are based on a limited number of observations extrapolated to represent not only regional changes but often changes across individual glaciers. Combining high resolution elevation data from contemporary laser-altimetry surveys and archived aerial photography makes it possible to measure historical changes across a glacier's entire surface. Here we present a high spatial resolution time-series for six Arctic glaciers in the Svalbard Archipelago spanning 1961 to 2005. We find increasing thinning rates before and after 1990 with elevation losses occurring most notably in the glaciers' upper reaches. In the absence of a clear meteorological driver, we recommend further investigation into a possible albedo amplification of prevailing meteorological trends to explain these higher elevation changes, which could have important consequences on the region's mass balance due to the sensitivity of its hypsometric distribution. However, the strong influence of decadal-scale variability, while explaining lower rates of mass loss reported in earlier studies, highlights that caution must be exercised when interpreting thinning rates when averaged over long periods.
Akt-activated Vascular Endothelial Cells Enhance Breast Cancer Stemness
Authors: Ghiabi Pegah , Raynaud Christophe , Arash Rafii Tabrizi Jeremy
Published: March 2012

Breast cancer is a major disease leading in both incidence and mortality in women. Although the mortality has been reduced by various therapy approaches, recurrence still occurs in many patients. Evidence indicates that tumor-initiating (cancer stem) cells may contribute to disease relapse, suggesting the importance of effective targeting of this cell population. Recently, it has been shown that the components of the tumor microenvironment, including tumor vascular endothelium, interact with
cancer stem cells through intracellular signaling pathways. However, the exact mechanism underlying this interaction is not known. In this study, we intend to investigate how the Akt-activated vascular endothelial cells (E4ORF1) communicate with defined populations of breast tumor. Moreover, we are interested to find out if notch pathway is regulating this crosstalk.

The cancer stem cells were enriched under serum-free conditions in 3D media to obtain mammospheres. To investigate how E4ORF1 maintains breast tumor cells and cancer stem cell in the absence of serum and cytokines, breast cancer MDA-MB231 and MCF-7 cells were co-cultivated with E4ORF1, its conditioned media, or in 3D media. In addition, the expression of pluripotency markers was assessed by real-time PCR in cancer cells after contact with E4ORF1 cells. Besides, the involvement of
notch pathway in E4ORF1 interaction with mammospheres was studied by using RNAi against Jagged-1.

Our preliminary results demonstrated that E4ORF1 cells were able to maintain cancer cells under serum-free conditions and in a contact-dependent manner. Also,they were able to enrich mammospheres in contact or after temporary exposure. Moreover, the expression of some pluripotency markers displayed a 1.5-fold increase in cancer cells co-cultured with E4ORF1 cells. Besides, Notch pathway activation seemed to be necessary for E4ORF1 to support mammosphere growth since there was a 3-fold decrease in sphere numbers in Jag-1-/MDA-MB231 cells.

These results suggest that E4ORF1 cells are capable of maintaining cancer stem cell population. Since this interaction is contact dependent, it might indicate the involvement of some intracellular signaling pathways. Our results show that notch might be involved in this crosstalk, which makes it a target for therapy in order to inhibit the cancer stem cell population to prevent breast cancer reappearance.
Clinical Applications of Human Induced Pluripotent: Challenges and Opportunities.
Authors: Vallier Ludovic
Published: March 2012

Human pluripotent stem cells can be derived from reprogrammed fibroblasts using overexpression of pluripotency factors (human induced pluripotent stem cells, or hIPSCs). These pluripotent cells are characterized by their capacity to self-renew in vitro while maintaining their property to differentiate into a broad number of cell types. By combining these unique properties, hIPSCs could enable the generation of large quantities of cells for clinical applications. Furthermore, the possibility of generating hIPSCs from somatic cells using epigenetic reprogramming represents a unique opportunity for regenerative medicine. Indeed, these pluripotent stem cells could enable the production of patient-specific cell types that are fully immuno-compatible with the original donor, thereby avoiding the need for immune suppressive treatment during cell-based therapy. hIPSCs can also be used to develop in vitro models of disease, allowing large-scale studies impossible with primary cell cultures or with biopsy material. This application has been proven useful to model neurodegenerative diseases, cardiac syndromes and inborn metabolic disorders in vitro for basic studies and drug screening.

While these results demonstrate that hIPSCs could be useful to study a broad number of disease in vitro, key limitations have to be solved before these pluripotent stem cells become fully useful with clinical applications in vivo. Current approaches to reprogram cells are often associated with important issues such as genetic and epigenetic instability. Furthermore, protocols available to direct differentiation of hIPSCs lack the necessary efficiency and systematically result in the production of fetal derivatives. While such embryonic cells are mature enough to model some diseases in vitro, they might not be sufficiently functional for mimicking diseases affecting adult cells or for cell therapy applications. Therefore, further efforts are required to develop novel method to reprogram somatic cells and to generate fully mature cells from human pluripotent cells. Here, we will discuss the potential solutions necessary to generate hIPSCs compatible with cell therapy approaches against degenerative diseases especially genetic disorders affecting the liver.
The Malnutrition of Obesity: Micronutrient Deficiencies That Promote Diabetes
Authors: Via Michael
Published: March 2012

Obesity and diabetes are increasing in prevalence worldwide. Despite excessive dietary consumption, obese individuals have high rates of micronutrient deficiencies. Deficiencies of specific vitamins and minerals that play important roles in glucose metabolism and insulin signaling pathways may contribute to the development of diabetes in the obese population. This paper reviews the current evidence supporting this hypothesis.
Incidence of Metabolic Syndrome and Its Risk Factors among Type 2 Diabetes Clinic Attenders in Isfahan, Iran
Authors: Janghorbani Mohsen , Amini Masoud
Published: March 2012

Aim. At present, little data exist about incidence and the risk factors associated with metabolic syndrome (MetS) in patients with type 2 diabetes mellitus (T2DM). The objectives of present study were to assess the incidence and risk factors of MetS in people with T2DM. Methods. During the mean (SD) follow-up period of 11.7 (4.8) years, 3,047 patients with T2DM and free of MetS at baseline have been examined to determine incidence and predictors of progression to MetS. A modified the National Cholesterol Education Program—Adult Treatment Panel III definition with body mass index (BMI) instead of waist circumference was used for the MetS. Results. The prevalence of MetS was 63.2% (95% CI: 62.3, 64.1). The incidence of MetS was 28.5 (95% CI: 26.8, 30.2) (25.9 men and 30.9 women) per 1,000 patient-years based on 35,677 patient-years of follow-up. Multivariate analysis revealed that higher BMI and education, lower and treatment with oral agent or insulin were associated with MetS. Conclusion. These are the first estimate of incidence and risk factors of MetS in patients with T2DM in Iran. These findings showed that the natural course of MetS is dynamic. The clinical management of patients with T2DM will contribute significantly to MetS prevention.
Image Retrieval Based on Content Using Color Feature
Authors: Afifi Ahmed J. , Ashour Wesam M.
Published: March 2012

Content-based image retrieval from large resources has become an area of wide interest in many applications. In this paper we present a CBIR system that uses Ranklet Transform and the color feature as a visual feature to represent the images. Ranklet Transform is proposed as a preprocessing step to make the image invariant to rotation and any image enhancement operations. To speed up the retrieval time, images are clustered according to their features using k-means clustering algorithm.
Evaluation of the Electrostatic Contribution to the Retention of Modified Nucleosides and Nucleobases by Zwitterionic Hydrophilic Interaction Chromatography
Authors: García-Gómez Diego , Rodríguez-Gonzalo Encarnación , Carabias-Martínez Rita
Published: March 2012

This work explores the benefits and limitations, on a quantitative basis, of using zwitterionic hydrophilic interaction chromatography (ZIC-HILIC) for the separation of several modified nucleosides and nucleobases of clinical interest. The target compounds were hydroxylated and methylated derivatives: 8-hydroxy-guanine, 8-hydroxy-guanosine, 8-hydroxy-2′-deoxyguanosine, 1-methyl-guanine, 7-methyl-guanine, and 9-methyl-guanine. A quantitative evaluation of the electrostatic interaction based on a systematic study of the nature and concentration of the salts in the mobile phase has been carried out. From the obtained results, it may be concluded that separation is based on a mechanism of partition and interaction through weak electrostatic forces: the contribution of the electrostatic interaction to the retention of the charged analytes reaching values between 25 and 52% at low salt concentration. However, the electrostatic contribution decreased progressively as the salt concentration rose.