Distribution by Scientific Domains
Distribution within Polymers and Materials Science

Kinds of Steel

  • austenitic stainless steel
  • austenitic steel
  • bearing steel
  • carbon steel
  • duplex stainless steel
  • ferritic steel
  • h13 tool steel
  • high-strength steel
  • low carbon steel
  • mild steel
  • reinforcing steel
  • stainless steel
  • strength steel
  • structural steel
  • tempered steel
  • tool steel

  • Terms modified by Steel

  • steel ball
  • steel bar
  • steel beam
  • steel construction
  • steel crown
  • steel disk
  • steel fibre
  • steel frame
  • steel grade
  • steel industry
  • steel member
  • steel pipe
  • steel plate
  • steel reinforcement
  • steel sample
  • steel sheet
  • steel specimen
  • steel structure
  • steel substrate
  • steel surface
  • steel tube
  • steel tubes
  • steel wire

  • Selected Abstracts

    Interfacial Microstructure of Chromium Oxide Coatings,

    X. Pang
    This paper presents a study of chromium oxide coatings' interfacial microstructure and structural properties affecting coating performance. Amorphous chromium and chromium oxide layers about 100 nm thick were detected at the Cr/steel and the Cr/coating interfaces, providing a solution for depositing thicker mechanically stable coatings with improved hardness, smaller grain size, and smooth surface. [source]

    Book and Media Reviews

    ADDICTION BIOLOGY, Issue 4 2000
    David Ball
    Books reviewed in this article: Book reviews in this column will primarily be of titles focusing completely, or in part, on biological aspects of addiction. However, significant titles of general relevance to the addictions field will also be included, even if they are not "biological", as will titles of general methodological and clinical relevance, even if they are not on "addictions". Similar considerations will apply to other media (software, audio tapes and CDs, videos, etc). However, specific "addictions" software applications seem to be relatively uncommon and, as these items are rarely reviewed elsewhere, we will endeavour to include reviews of some of the older programmes that are still useful, as well as new titles that appear. I would appreciate suggesti ons of any items suitable for reviews, but especially software and other media of specifi c relevance to the addictions. Please contact: Dr David Ball, National Addiction Centre, 4 Windsor Walk, London SE5 8AF, UK. Dual Diagnosis and Treatment: substance abuse and co-morbid medical and psychiatric disorders HENRY R. KRANZLER & BRUCE J. ROUNSAVILLE (Eds) Improving the Care of People in Substance Misuse Ser vices: clinical audit project examples KIRSTY MACLEAN STEEL & CLAIRE PALMER Software European Legal Texts on Drugs (CD-Rom) [source]


    H. Boudoukha
    First page of article [source]

    In Situ SEM Observation and Analysis of Martensitic Transformation During Short Fatigue Crack Propagation in Metastable Austenitic Steel,

    Ulrich Krupp
    Abstract High cycle fatigue (HCF) life of metastable austenitic steels is governed by the ability of the parent austenite phase to transform into ,, martensite via metastable , martensite. The mechanism of this strain-induced transformation is closely related to the grain size, the crystallographic orientation distribution, as well as to amplitude, and cyclic accumulation of plastic strain. Aim of the present study is to identify and to quantitatively describe the basic principles of strain-induced martensite formation by means of in situ cyclic deformation experiments in a scanning electron microscope (SEM) in combination with electron back-scattered diffraction (EBSD) and numerical modeling using a boundary element approach. It was shown that during HCF loading martensite formation is inhomogeneous and not directly linked with crack initiation. Only when the fatigue crack propagates by operating multiple slip systems, the cyclic plastic zone exhibits martensitic transformation. [source]

    Metastable Austenite in 17,4 Precipitation-Hardening Stainless Steel Produced by Selective Laser Melting

    Luca Facchini
    Abstract A 17,4 precipitation-hardening stainless steel produced by selective laser melting contains 72% metastable and heavily faulted austenite and 28% highly dislocated and twinned martensite. The mechanical behavior is characterized by exceptional work hardening and a two-step plastic field, which are due to the strain-induced transformation of austenite and to the structural characteristics of the deformed austenite and martensite. Both phases tend to accumulate stacking faults in the first step and twins in the second. [source]

    Phase Reversion-Induced Nanograined/Ultrafine-Grained Structures in Austenitic Stainless Steel and their Significance in Modulating Cellular Response: Biochemical and Morphological Study with Fibroblasts,

    R. Devesh Kumar Misra
    Materials science, engineering, and biological sciences have been combined to improve the tissue compatibility of medical devices. In this regard, nano/ultrafine structuring of austenitic stainless steel obtained using an innovative approach of "phase-reversion" has been evaluated for modulation of cellular activity. The biochemical and morphology study with fibroblasts point toward the improvement of tissue compatibility on comparison with coarse-grained structures, strengthening the foundation of nanostructured materials for bio-medical applications. [source]

    Study of Fatigue Damage Micromechanisms in a Duplex Stainless Steel by Complementary Analysis Techniques

    Ahmed El Bartali
    The low-cycle fatigue (LCF) damage micromechanisms are studied in a duplex stainless steel at room temperature using complementary analysis techniques. Surface damage is observed in real-time with an in-situ microscopic device during a low-cycle fatigue test. Slip systems activated in each grain in each phase are identified from SEM photographs and EBSD measurements. The surface relief appeared at the end of the test is measured with an interferometric profilometer. Displacement and strain fields on the microstructural scale are calculated using DIC technique from surface images taken during cycling. Observations were combined to analyse damage mechanisms from slip marking appearance to strain localisation and crack initiation. [source]

    The Anisotropic Fatigue Behavior of Forged Steel,

    Etienne Pessard
    This paper deals with the anisotropic fatigue behavior of a bainitic steel and aims at improving the fatigue criteria used for the design of forged components. The two different types of anisotropic fatigue behavior observed in the literature are discussed. Experimental results are presented for a hot-rolled steel which demonstrates the effect of elongated inclusions on the fatigue behavior. A model is proposed to account for the anisotropic fatigue behavior. [source]

    Evaluation of Transient Liquid Phase Bonding Between Titanium and Steel

    Ahmed Elrefaey
    An investigation of microstructural development in transient liquid phase (TLP) bonds between commercially pure titanium and low carbon steel is presented in this study. Changes in the joint region and surrounding substrates were examined as a function of holding time at temperatures of 870 and 910 °C. Both interfacial microstructures and mechanical properties of brazed joints were investigated to evaluate joint quality. [source]

    Influence of Filler Composition on the Microstructure and Mechanical Properties of Steel,Aluminum Joints Produced by Metal Arc Joining (Adv. Eng.

    The cover shows the inverse pole figure map obtained by EBSD on the cross section of an hybrid aluminium-to-steel joint produced by the Cold Metal Transfer welding technique on a specially designed butt geometry,More details can be found in the article of L. Agudo et al. on page 350. [source]

    Influence of Filler Composition on the Microstructure and Mechanical Properties of Steel,Aluminum Joints Produced by Metal Arc Joining,

    Leonardo Agudo Jácome
    Chemical joining of aluminum to steel parts is one of the main challenges in the automotive industry to achieve sound economical solutions for required automobile weight reduction. The cold metal transfer (CMT) is a fusion welding process developed to meet that challenge. It is shown in this paper how the choice of proper filler materials can yield appropriate mechanical performance of specially designed dissimilar CMT butt joints by improving the seam characteristics and weld bead properties. [source]

    Biocompatibility of Lotus-type Stainless Steel and Titanium in Alveolar Bone

    Y. Higuchi
    Abstract Lotus-type porous stainless steel (SUS304L) and porous titanium were fabricated by unidirectional solidification in a mixture gas of hydrogen and argon. The porous metals which were cut into 5,mm cubes (non-dehydrogenated) and 3.4,mm,,×,5,mm cylinders (dehydrogenated) were implanted into the canine mandible alveolar bone for two, four and eight weeks for animal experiments. The changes in the tissues were observed using SEM. For porous stainless steel (cylindrical; dehydrogenated) new formation of bones was observed around the sample in two weeks without any sign of bony ingrowth into the pores. The osteogenesis was found in shallow areas in the pores in four weeks and deep in the pores in eight weeks. Porous titanium, on the other hand, showed deep ingrowth of new bones in four weeks. Our observations allowed us to expect application of the porous metals as biomaterials. They maintain mechanical strength and are lighter in weight so that it is expected to be applied for dental implants and core materials of artificial bones. [source]

    Unlubricated Wear Behavior of Ce-TZP/ Al2O3 Nanocomposites Against Bearing Steel,

    G. Yang
    Unlubricated friction and wear tests of Ce-TZP/Al2O3 nanocomposites against bearing steel were performed. In order to elucidate the wear mecahnism, the morphological investigation and phase structural analysis of worn surfaces were carried out by X-ray diffractometer and scanning electron microscope. Additionally, three kinds of wear mechanisms such as plastic deformation, adhesive wear and brittle fracture have been revealed. [source]

    Recrystallization and Texture in a Ferritic Stainless Steel: an EBSD Study,

    C.W. Sinclair
    The recrystallization behavior of laboratory-processed AISI409 ferritic stainless steel sheet has been studied with a focus on texture inhomogeneity and "sluggish" recrystallization kinetics, mainly using EBSD in the scanning electron microscope. Pronounced texture gradients were observed in some grain orientations (see Figure for a TEM image of the , versus ,-grain border region) and correlated to the deformation-induced substructure. The strong pinning of some boundaries has been linked not only to textural effects, but also to the precipitation of fine titanium carbonitrides. [source]

    Long-Cycle Electrochemical Behavior of Multiwall Carbon Nanotubes Synthesized on Stainless Steel in Li Ion Batteries

    Charan Masarapu
    Abstract Carbon nanotubes (CNTs) are considered to be excellent candidates for high performance electrode materials in Li ion batteries. The nanometer-sized pore structures of CNTs can provide the hosting sites for storing large numbers of Li ions. A short diffusion distance for the Li ions may bring about a high discharge rate. The long-cycle performance of aligned multiwalled carbon nanotubes (MWNTs) directly synthesized on stainless-steel foil as an anode material in lithium battery is demonstrated. An increase in the specific capacity with an increase in the cycle number is observed. Starting at a value of 132,mA hg,1 in the first cycle at a current rate of 1,C, the specific capacity increased about 250% to a value of 460,mA hg,1 after 1,200 cycles. This is an unusual but a welcoming behavior for battery applications. It is found that the morphology of the MWNTs with structural and surface defects and the stainless-steel substrate play an important role in enhancing the capacity during the cycling process. [source]

    The Impact of Industrial Restructuring on Earnings Inequality: The Decline of Steel and Earnings in Pittsburgh

    GROWTH AND CHANGE, Issue 1 2004
    Patricia Beeson
    ABSTRACT Inter-industry employment shifts were largely responsible for changes in the income distribution in the Pittsburgh region during the 1980s. Kernel density estimators were used, together with decomposition techniques developed by DiNardo et al. (1996) to show that industry shifts were responsible for over 90 percent of the earnings reductions at some points on the earnings distribution. Most of the losses at the lower end of the distribution occurred in the early 1980s as the economy plunged into a deep recession. The recovery in the later part of the decade brought little improvement as earnings in the lower part of the distribution continued to fall with the increase in employment of part-time workers in the low-wage trade and service sectors. [source]

    Favorable Modulation of Pre-Osteoblast Response to Nanograined/Ultrafine-grained Structures in Austenitic Stainless Steel

    ADVANCED MATERIALS, Issue 12 2009
    R.D.K. Misra
    Nanograined (NG)/ultrafine-grained (UFG)structures show enhanced cellular response of pre-osteoblasts. Cell proliferation, viability, and morphology on phase-reversion annealed NG/UFG austenitic stainless steel were observed to be favorably modulated in comparison to conventional coarse-grained austenitic stainless steel. The improvement in cellular response is ascribed to NG/UFG structure and hydrophilicity of the cell substrate. [source]

    Wear Mechanisms of TiB2 and TiB2,TiSi2 at Fretting Contacts with Steel and WC,6 wt% Co

    Golla Brahma Raju
    Unlubricated fretting wear tests on TiB2 and TiB2,5 wt% TiSi2 ceramics against two different mating materials (bearing grade steel and WC,6 wt% Co balls) were performed with a view to understand the counterbody-dependent difference in friction and wear properties. The fretting experiments were conducted systematically by varying load (2,10 N) at an oscillating frequency of 4 Hz and 100 ,m linear stroke, for a duration of 100,000 cycles. Adhesion, abrasion, and three-body wear have been observed as mechanisms of material damage for both the TiB2/steel and TiB2/WC,Co tribosystems. The third body is predominantly characterized as tribochemical layer for TiB2/steel and loose wear debris particles for TiB2/WC,Co tribocouple. An explanation on differences in tribological properties has been provided in reference to the counterbody material as well as microstructure and mechanical properties of flat materials. [source]

    Rings of Steel, Rings of Concrete and Rings of Confidence: Designing out Terrorism in Central London pre and post September 11th

    Jon CoaffeeArticle first published online: 24 FEB 200
    This article is a reaction to the rapid changes many urban areas are undertaking in attempts to counter the contemporary terrorist threat since the devastating events of September 11th. The response of central London authorities both pre- and post- September 11th is used as the lens through which to view attempts to reduce the real and perceived threat of terrorist attack through the adoption of territorial approaches to security, both physical and technological, which are increasingly being utilized at ever-expanding spatial scales. It argues that this situation all too often produces a scenario of ,splintered urbanism' as security rings are thrown up around carefully selected sections of cities deemed most at risk. It further argues for a balance to be struck between competing concerns for freedom of access, mobility and other democratic freedoms, and the need for cities to adopt increasingly militarized security perspectives in their counter-terrorism efforts. Cet article présente une réaction aux rapides changements que de nombreuses zones urbaines entreprennent afin de contrer la menace terroriste actuelle depuis les ravages du 11 septembre. La réponse des autorités du centre de Londres, à la fois avant et après cette date, sert ainsi de loupe permettant d'observer les efforts de minimisation de cette menace d'agression, tant subjective que réelle. Il s'agit de démarches territoriales à l'égard de la sécurité (matérielle et technologique) appliquées de plus en plus souvent à des échelles spatiales sans cesse élargies. De cette situation, naît trop souvent un scénario ,d'urbanisme fragmenté', les anneaux de sécuritéétant jetés autour de portions soigneusement sélectionnées de villes jugées le plus en danger. L'article défend la nécessité de trouver un équilibre entre les préoccupations opposées que sont les liberté d'accès, mobilité ou autres libertés démocratiques et le besoin des villes d'adopter des perspectives sécuritaires de plus en plus militarisées dans leurs tentatives contre le terrorisme. [source]

    Microtopography of metal surfaces influence fibroblast growth by modifying cell shape, cytoskeleton, and adhesion

    David O. Meredith
    Abstract Stainless Steel (SS), titanium (cpTi), and Ti-6Al-7Nb (TAN) are frequently used metals in fracture fixation, which contact not only bone, but also soft tissue. In previous soft tissue cytocompatibility studies, TAN was demonstrated to inhibit cell growth in its "standard" micro-roughened state. To elucidate a possible mechanism for this inhibition, cell area, shape, adhesion, and cytoskeletal integrity was studied. Only minor changes in spreading were observed for cells on electropolished SS, cpTi, and TAN. Cells on "standard" cpTi were similarly spread in comparison with electropolished cpTi and TAN, although the topography influenced the cell periphery and also resulted in lower numbers and shorter length of focal adhesions. On "standard" microrough TAN, cell spreading was significantly lower than all other surfaces, and cell morphology differed by being more elongated. In addition, focal adhesion numbers and mean length were significantly lower on standard TAN than on all other surfaces, with 80% of the measured adhesions below a 2-µm threshold. Focal adhesion site location and maturation and microtubule integrity were compromised by the presence of protruding ,-phase microspikes found solely on the surface of standard TAN. This led us to propose that the impairment of focal adhesion numbers, maturation (length), and cell spreading to a possibly sufficient threshold observed on standard TAN blocks cell cycle progress and eventually cell growth on the surface. We believe, as demonstrated with standard cpTi and TAN, that a difference in surface morphology is influential for controlling cell behavior on implant surfaces. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1523,1533, 2007 [source]

    Compositionally Graded Aluminum Oxide Coatings on Stainless Steel Using Laser Processing

    Partha P. Bandyopadhyay
    A 1.5 mm thick fully dense alumina coating with a composition gradient from 100% Ni,20 wt% Cr at the substrate to 100% alumina on top has been developed on a 316 stainless steel sheet using Laser Engineered Net Shaping (LENSÔ). The gradient coatings showed hardness in the range of 1800,2000 Hv, one of the highest reported so far due to high-density layers. During laser deposition, ,-Al2O3 found to grow along the deposition direction with coarse columnar structure. The inherent advantage of this approach is to control simultaneously both location and composition leading to better interfacial properties of coatings. [source]

    Are you an invited speaker?

    A bibliometric analysis of elite groups for scholarly events in bioinformatics
    Participating in scholarly events (e.g., conferences, workshops, etc.) as an elite-group member such as an organizing committee chair or member, program committee chair or member, session chair, invited speaker, or award winner is beneficial to a researcher's career development. The objective of this study is to investigate whether elite-group membership for scholarly events is representative of scholars' prominence, and which elite group is the most prestigious. We collected data about 15 global (excluding regional) bioinformatics scholarly events held in 2007. We sampled (via stratified random sampling) participants from elite groups in each event. Then, bibliometric indicators (total citations and h index) of seven elite groups and a non-elite group, consisting of authors who submitted at least one paper to an event but were not included in any elite group, were observed using the Scopus Citation Tracker. The Kruskal,Wallis test was performed to examine the differences among the eight groups. Multiple comparison tests (Dwass, Steel, Critchlow,Fligner) were conducted as follow-up procedures. The experimental results reveal that scholars in an elite group have better performance in bibliometric indicators than do others. Among the elite groups, the invited speaker group has statistically significantly the best performance while the other elite-group types are not significantly distinguishable. From this analysis, we confirm that elite-group membership in scholarly events, at least in the field of bioinformatics, can be utilized as an alternative marker for a scholar's prominence, with invited speaker being the most important prominence indicator among the elite groups. [source]

    Corrosion Books: Corrosion of Steel in Concrete.

    By: John P. Broomfield

    Fortschritte beim Rührreibschweißen von Aluminium, Magnesium und Stahl

    S. Sheikhi Dr.-Ing.
    Friction Stir Welding; Aluminium; Magnesium; Steel; Tailored welded blanks Abstract Das Rührreibschweißen (Friction Stir Welding (FSW)) stellt einen innovativen Schweißprozess zum Fügen von Leichtmetallen insbesondere von Aluminiumlegierungen dar. Die Herstellung von Aluminiumverbindungen mit konventionellen Schmelzschweißverfahren erfüllt nicht immer und nicht bei jeder Legierung die von der Industrie gestellten Qualitätsanforderungen. Das Rührreibschweißen stellt eine Alternative zu den Schmelzschweißverfahren dar. Die entstehenden Schweißnähte weisen gute mechanische Eigenschaften auf, das Verfahren ist robust und seine Reproduzierbarkeit sehr gut. Im Rahmen dieser Arbeit wird der Einsatz des Rührreibschweißens zum Fügen von Aluminium- und Magnesiumlegierungen erläutert. Dabei werden artgleiche und artungleiche Verbindungen und deren mechanische Eigenschaften beschrieben. Das Rührreibschweißen von Stahl mit seinen besonderen Anforderungen an das Schweißwerkzeug wird ebenfalls vorgestellt. Progresses on the friction stir welding of aluminium, magnesium and steel Friction Stir Welding (FSW) represents an innovative welding process for joining light metal, especially, aluminium and its alloys. Friction Stir Welding offers an attractive alternative to conventional fusion welding processes because of the excellent properties (particularly ductility), reproducibility, robustness, and surface finish obtained with the process. Within the scope of this work the Friction Stir Welding-Process with its possible joint configurations is explained. The focus of this work concentrates on weldability studies concerning cladded aluminium alloys, aluminium cast alloys, aluminium tailored welded blanks both from similar and dissimilar joints produced in aluminium, magnesium and steel. The mechanical properties of the welded samples will be discussed. [source]

    We Ran One Regression,

    David F. Hendry
    The controversy over the selection of ,growth regressions' was precipitated by some remarkably numerous ,estimation' strategies, including two million regressions by Sala-i-Martin [American Economic Review (1997b) Vol. 87, pp. 178,183]. Only one regression is really needed, namely the general unrestricted model, appropriately reduced to a parsimonious encompassing, congruent representation. We corroborate the findings of Hoover and Perez [Oxford Bulletin of Economics and Statistics (2004) Vol. 66], who also adopt an automatic general-to-simple approach, despite the complications of data imputation. Such an outcome was also achieved in just one run of PcGets, within a few minutes of receiving the data set in Fernández, Ley and Steel [Journal of Applied Econometrics (2001) Vol. 16, pp. 563,576] from Professor Ley. [source]

    Deposition of SiO, -Like Thin Films from a Mixture of HMDSO and Oxygen by Low Pressure and DBD Discharges to Improve the Corrosion Behaviour of Steel

    Camille Petit-Etienne
    Abstract Hexamethyldisiloxane was used to deposit silicon dioxide thin films using a low frequency plasma reactor at low pressure as well as a dielectric barrier discharge (DBD) at atmospheric pressure. FT-IR, XPS, EIS, SEM and ellipsometry were used to analyse the samples. The results show that, at low pressure, the deposited films which are smooth, continuous and dense present a polymer-like structure. By carrying out the film deposition after an oxygen plasma pretreatment step, a further improvement in the protective properties is achieved, which is observed in the case of SiO, coatings with 13.56 MHz RF generators.1 At atmospheric pressure, the deposited films present an inorganic character deposited in open air and a polymer-like one deposited under a controlled nitrogen atmosphere in our DBD reactor. The latter also allows continuous films which present the best anti-corrosive properties (which have been studied for the first time for anti-corrosive properties) when they contain some carbon incorporated. [source]

    Effect of Carbon on the Compound Layer Properties of AISI H13 Tool Steel in Pulsed Plasma Nitrocarburizing

    Rodrigo L. O. Basso
    Abstract Due to the mechanical and inertness properties of the , -Fe2-3N phase, its formation as a compact monolayer is most wanted in plasma surface treatments of steels. This phase can be obtained by the inclusion of carbon species in the plasma. In this work, we present a systematic study of the carbon influence on the compound layer in an AISI H13 tool steel by pulsed plasma nitrocarburizing process with different gaseous ratios (0%,,,[CH4]/[N2,+,CH4,+,H2],,,4%). The plasma treatment was carried out for 5 h at 575,°C. The microstructure and phase composition of the modified layers were studied by scanning electron microscopy and X-ray diffraction, respectively. X-Ray photoelectron spectroscopy was used to measure the relative concentration of carbon and nitrogen on the surface. The hardening profile induced by the nitrocarburized process is also reported. [source]

    Precipitates Temperature Dependence in Ion Beam Nitrited AISI H13 Tool Steel

    Luiz F. Zagonel
    Abstract AISI H13 tool steel samples were nitrided using broad nitrogen ion beams in a high-vacuum chamber at different temperatures. At 400,°C, a thin , -Fe2-3N phase forms on the top of a shallow nitrided layer and the nitrogen distribution follows a complementary error function. At 500,°C, deviations from this behavior are observed and a thick , -Fe2-3N layer is formed. At 600,°C, no , -Fe2-3N phase is formed and the nitrogen profile is step-like. At such a temperature, coarse nitride precipitates are observed. Also, carbon losses (decarburizing) are observed upon nitriding at and above 500,°C. [source]

    Women of Steel: Constructing and Contesting New Gendered Geographies of Work in the Australian Steel Industry

    ANTIPODE, Issue 2 2000
    Liza Tonkin
    The article argues that although structuralist-inspired approaches to steel restructuring have provided significant insights and recognised the role of "labour" in sectoral change, such studies have predominantly equated labour politics with unionism, downplaying the impact of other forms of workers' politics. This has created a problematic disjunction between "real world" events and academic research, with ensuing issues for policy development and delivery. In response to this difficulty, the paper builds on Herod's concept of a labour geography to develop multiple labour geographies of power, an approach that describes different forms of workers' politics. To illustrate this approach, the paper presents female steelworkers' politics of restructuring. It details the Jobs for Women Campaign in Wollongong, Australia, a 1980s place-based initiative that sought to gain blue-collar employment for women in the local steelworks. The study demonstrates how female steelworkers developed restructuring politics addressing gender and employment discrimination, issues not normally associated with labour politics. The paper concludes that such workers' struggles need to be analysed as they affect restructuring impacts and processes. [source]

    Ecdysteroid receptor (EcR) is associated with microtubules and with mitochondria in the cytoplasm of prothoracic gland cells of Rhodnius prolixus (Hemiptera)

    Xanthe Vafopoulou
    Abstract We have shown previously that EcR in larval Rhodnius is present in the cytoplasm of various cell types and undergoes daily cycling in abundance in the cytoplasm (Vafopoulou and Steel, 2006. Cell Tissue Res 323:443,455). It is unknown which organelles are associated with EcR. Here, we report that cytoplasmic EcR in prothoracic gland cells is associated with both microtubules and mitochondria, and discuss the implications for both nuclear and non-genomic actions of EcR. EcR was localized immunohistochemically using several antibodies to EcR of Manduca and Drosophila and a confocal laser scanning microscope. Double labels were made to visualize EcR and (1) microtubules (using an antibody to tyrosylated ,-tubulin) and (2) mitochondria (using a fluorescent MitoTracker probe), both after stabilization of microtubules with taxol. EcR co-localized with both tubulin and mitochondria. All the different EcR antibodies produced similar co-localization patterns. EcR was seen in the perinuclear aggregation of mitochondria, indicating that mitochondria are targets of ecdysone, which could influence mitochondrial gene transcription. EcR was also distributed throughout the microtubule network. Co-localization of EcR with tubulin or mitochondria was maintained after depolymerization of microtubules with colchicine. Treatment with taxol resulted in accumulation of EcR in the cytoplasm and simultaneous depletion of EcR from the nucleus, suggesting that microtubules may be involved in targeted intracellular transport of EcR to the nucleus (genomic action) or may play a role in rapid ecdysone signal transduction in the extranuclear compartment, i.e., in non-genomic actions of ecdysone. These findings align EcR more closely with steroid hormone receptors in vertebrates. © 2009 Wiley Periodicals, Inc. [source]