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Terms modified by Straight Selected AbstractsMagnetic-Field-Assisted Electrospinning of Aligned Straight and Wavy Polymeric NanofibersADVANCED MATERIALS, Issue 22 2010Yaqing Liu Aligned straight and wavy fibers of biodegradable poly(D,L-lactic- co -glycolic acid) (PLGA) are fabricated using a magnetic-field-assisted electrospinning method. PLGA fibrous matrices prepared by this method can guide the growth of pluripotent murine mesenchymal stem cells. While the stem cells on the randomly oriented fibers adapt pseudo-sphere-like shape, those on aligned fibers exhibit elongated morphology along the long axes (see figure). [source] Miracles and Extraordinary Experience in Northern Kenya by Bilinda StraightAMERICAN ETHNOLOGIST, Issue 2 2008DOROTHY L. HODGSON First page of article [source] Straight to the bar: Molecular nanostructures, graphene, nanotubes.PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 3 200717 March 200, Austria, Kirchberg, XXIst International Winterschool on Electronic Properties of Novel Materials (IWEPNM 2007) Conference Reports are meant to offer an authoritative view on a recently held scientific meeting rather than a comprehensive list of the conference presentations. Authors are invited to describe what they feel were the most interesting contributions. The Kirchberg Winterschool provided a platform for reviewing and discussing new developments in the field of electronic properties of molecular nanostructures and their applications such as carbon nanotubes, graphene and single molecules. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Long-term Equity and Operating Performances following Straight and Convertible Debt Issuance in the U.S.,ASIA-PACIFIC JOURNAL OF FINANCIAL STUDIES, Issue 3 2009Mookwon Jung Abstract This paper shows that long-term equity and operating performances that follow straight and convertible debt issuance in the U.S. are different, just as are announcement-period market reactions, supporting the notion that market investors initially underreact to a selective event of convertible debt issuance. Cross-sectional tests reveal that firms issuing convertible debt often suffer stock underperformance partly because of their deteriorating fundamentals subsequently to the issuance. Even when each convertible bond directly matches with a straight bond that has a similar offering date and issuer and bond characteristics, convertible debt issuers still significantly under-perform straight debt issuers, supporting that what matters for long-term equity and operating performances is the type of debt offering. [source] Straight and Versatile Synthesis of Substituted Perhydrofuro[2,3-b]pyrans from 2-Chloromethyl-3-(2-methoxyethoxy)propene.CHEMINFORM, Issue 42 2003Francisco Alonso No abstract is available for this article. [source] NaV1-xP2S6 (x = 0.16): A New Compound with Infinite Straight 1, [V0.837P2S6] - Chains that Exfoliate Forming Gels.CHEMINFORM, Issue 37 2003Servane Coste Abstract For Abstract see ChemInform Abstract in Full Text. [source] ,Have You Got a Boyfriend or are You Single?': On the Importance of Being ,Straight' in Organizational ResearchGENDER, WORK & ORGANISATION, Issue 3 2006Attila Bruni The article focuses on heterosexuality as a covert feature of organization studies as well as of organizational research. In fact, while organization studies have discussed the gendered and the gendering aspects of organizational practices and organizational theory, the implication of heterosexuality has yet to receive intensive analysis in these fields. And while the mutual and reflexive constitution of the observer and the observed has been the topic of a considerable amount of research, the dimension of (heterosexual) desire in this process of mutual constitution is still largely unexplored. Referring to three different episodes that occurred while the author was doing organizational ethnography, the article suggests that a heterosexual model of desire is called into action both in organizational and research activities and that focusing on it can be an occasion to question not only the gender (and heterosexual) biases of organizational practices but also the way in which gender and sexuality are mobilized while doing research. In particular, on the basis of the concept of cathexis, the article shows how heterosexuality is learnt and enacted as a situated practice and through a variety of processes: performing power, negotiating and displaying that one belongs to an organizational culture, obscuring the hetero-normativity of professional identities and neglecting the emotional engagement that characterizes research activities and that exposes the researcher to an otherwise vulnerable position. [source] Crystal growth by the travelling heater method using tapered crucibles and applied rotating magnetic fieldCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2010J. Roszmann Abstract Crystal growth experiments were carried out by the Travelling Heater Method using tapered growth ampoules with and without the application of a rotating magnetic field. The objective was to enhance its commercial potential by reducing the size of required seed crystals and increasing the growth rate. To this end, a number of GaSb crystals were grown using either 25 mm diameter straight, or 10 mm to 25 mm tapered growth ampoules. Growth rates of 2 mm/day and 5 mm/day were employed. The effect of rotating magnetic fields of several strengths and frequencies was examined. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Low temperature powder diffraction and DFT solid state computational study of hydrogen bonding in NH4VO3CRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2009. Smr Abstract The crystal structure of NH4VO3 was refined by the geometry optimization done by total energy minimization in solid state using DFT/plane waves approach. The lattice parameters were derived by the Le Bail technique from the low temperature X-ray (40-293 K) and synchrotron (100-293 K) powder diffraction data. The structure is formed by the infinite chains of irregular VO4 tetrahedra running approximately parallel to the c -axis, which are interlinked by the ammonium ions placed between them. The ammonium ions link to the [VO4], chains through one linear, one bifurcated and two trifurcated N-H,O hydrogen bonds. Considering their stability there are six distinct N-H,O hydrogen bonds: two strong with the N-H,O bond angles close to the straight, two medium with the bond angles of 123° and 148° and two very bent (105° and 107°) and hence weak hydrogen bonds. There is a reasonable agreement between the energies of the stretching ,(NH) modes estimated using the optimised N,O contact distances and those obtained experimentally. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Gravity bias in young and adult chimpanzees (Pan troglodytes): tests with a modified opaque-tubes taskDEVELOPMENTAL SCIENCE, Issue 3 2007Masaki Tomonaga Young human children at around 2 years of age fail to predict the correct location of an object when it is dropped from the top of an S-shape opaque tube. They search in the location just below the releasing point (Hood, 1995). This type of error, called a ,gravity bias', has recently been reported in dogs and monkeys. In the present study, we investigated whether young and adult chimpanzees also show such a gravity bias in a modified version of the original opaque-tube task. The original task by Hood and colleagues required the subject to search in a location after the object had fallen, while in the task reported here, subjects were required to predict the location before the object was dropped. Thus the present procedure does not involve explicit invisible displacement operations, one of the important components of the original procedure. In Experiment 1 both young (1.5,2.5-year-old) and adult chimpanzees predicted the location of falling food items below the releasing point even when crossed tubes were used. These gravity errors remained after the extensive experience of using the tubes themselves. Experiment 2 further tested adult and 4-year-old chimpanzees under the set-up in which the straight and crossed tubes were simultaneously presented. The results were the same as those in the previous test, suggesting that developmental changes and learning effect do not affect the gravity bias in chimpanzees. [source] Searching for food in the wild: a nonhuman rimate's expectations about invisible displacementDEVELOPMENTAL SCIENCE, Issue 1 2001Marc D. Hauser Five experiments involving invisible displacements were run on a population of semi-free-ranging rhesus monkeys (Macaca mulatta). The goal of these experiments was to assess, without training, the kinds of expectations individuals spontaneously set up when an object has moved out of sight. The first experiment, modeled after studies of human infants and children, involved a table with one box on the top surface and a second box lined up below on the ground. An occluder was placed in front of the table, blocking the subject's view. A piece of food was then dropped behind the occluder, above the top box. The presenter then removed the occluder, walked away, and allowed the subject to approach. Consistently, subjects searched in the incorrect bottom box. This error can be interpreted as a failure to understand solidity, containment, or some other factor. It can also be interpreted as an error guided by a gravity bias, i.e. an expectation that all falling objects fall straight down or to the lowest point. Experiments 2,5 tested these alternative hypotheses. Results show that rhesus monkeys do not have an inherent bottom box bias, are not avoiding the top box, and do recognize that in some contexts boxes can contain or hold food. Thus, for example, when the two boxes are placed on the ground, one in front of the other, and occluded, subjects search in the near box after a piece of food has been rolled behind the occluder (horizontal trajectory). This shows that rhesus can solve an invisible displacement problem that involves solid containers, where one container blocks travel to the other container. We conclude that the rhesus monkey's error in Experiment 1 is guided by an expectation that all falling objects fall straight down or, at least, to the lowest point. This expectation represents a limitation of their knowledge of physical objects and events. [source] COLLAPSE-SUBMERGENCE METHOD: SIMPLE COLONOSCOPIC TECHNIQUE COMBINING WATER INFUSION WITH COMPLETE AIR REMOVAL FROM THE RECTOSIGMOID COLONDIGESTIVE ENDOSCOPY, Issue 1 2007Takeshi Mizukami Colonoscopy is a difficult examination to conduct for inexperienced examiners. In an attempt to improve the view, there is often a tendency to overinsufflate air, which causes elongation or acute angulations of the colon and makes passage of the scope difficult. Sakai et al. were the first to describe a simple colonoscopic technique using water infusion instead of air insufflation. We have modified this technique to simplify the procedure further by combining water infusion using disposable syringes with complete air suction from the rectum to the descending colon. With the resultant elimination of the boundary lines between water and air, a good view of the lumen is obtained though the transparent water. With the patient in the left lateral position, this procedure allows the water to flow straight down into the descending colon through the ,collapsed' lumen, and the scope to be easily negotiated through the straightened recto-sigmoid colon and sigmoid-descending colon junction with minimum discomfort. Measurements of the patients' abdominal circumference during colonoscopy showed that colonic distension hardly occurred. Under supervision by the author, six complete novices were allowed to insert the colonoscope within 10 min by this method for one patient per week, as long as the patients did not complain of pain. The average trial number for the first cecal intubation within 10 min was 3.3, and the average success rate during the first 3 months was 58.6%. We believe that this ,collapse-submergence method' is easy to master, even for inexperienced examiners. [source] How to manage difficulties with colonoscope insertionDIGESTIVE ENDOSCOPY, Issue 2 2001Masaaki Miyaoka Unsuccessful insertion of a colonoscope is usually as a result of bending or looping of the scope. Looping of the colonoscope increases when too much air is insufflated or the scope is inserted with undue force, resulting in increased pain and risk of perforation. Successful insertion therefore requires careful handling of the scope to keep it straight, careful regulation of air levels, shortening of the colon length by gathering of the colon folds and rapid correction of any looping that should occur. This can be complicated in cases with an unusually long colon or with adhesion. The use of a colonoscope with variable rigidity or a small-caliber colonoscope is recommended to increase the rate of successful insertion to relieve pain and to prevent accidents. [source] Structure of sperm, spermatozeugmata and ,lateral organs' in the bivalve Arthritica (Galeommatoidea: Leptonidae)ACTA ZOOLOGICA, Issue 1 2009Åse Jespersen Abstract The position and structure of paired ,lateral organs' in the foot of Arthritica semen and Arthritica bifurca might indicate a chemosensory function. In both species part of the organ is also glandular. In A. semen the glandular epithelium is detached piecemeal and, probably by means of the foot, is moved to and grafted upon the gills of the same individual. The transferred epithelia appear as disk-shaped actively secretory ,gill bodies' which, attached to the abfrontal side of the inner demibranch, replace the ordinary unciliated gill epithelium. The secretion is liberated into the suprabranchial chamber, which serves as a marsupium, but its function is uncertain. Arthritica semen is a protandric hermaphrodite and produces very large ova that undergo a direct development that results in a non-planktonic lecithotrophic crawling juvenile stage. The sperm cells have filiform nuclei that are straight in the euspermatozoa and more or less helicoidal in what is considered to represent paraspermatozoa. By a process of aggregation, spermatozeugmata are formed which consist exclusively either of euspermatozoa or paraspermatozoa. Spermatozoa are stored in the oviduct in A. semen but in paired seminal receptacles in A. bifurca. [source] A low-dimensional physically based model of hydrologic control of shallow landsliding on complex hillslopesEARTH SURFACE PROCESSES AND LANDFORMS, Issue 13 2008Ali Talebi Abstract Hillslopes have complex three-dimensional shapes that are characterized by their plan shape, profile curvature of surface and bedrock, and soil depth. To investigate the stability of complex hillslopes (with different slope curvatures and plan shapes), we combine the hillslope-storage Boussinesq (HSB) model with the infinite slope stability method. The HSB model is based on the continuity and Darcy equations expressed in terms of storage along the hillslope. Solutions of the HSB equation account explicitly for plan shape by introducing the hillslope width function and for profile curvature through the bedrock slope angle and the hillslope soil depth function. The presented model is composed of three parts: a topography model conceptualizing three-dimensional soil mantled landscapes, a dynamic hydrology model for shallow subsurface flow and water table depth (HSB model) and an infinite slope stability method based on the Mohr,Coulomb failure law. The resulting hillslope-storage Boussinesq stability model (HSB-SM) is able to simulate rain-induced shallow landsliding on hillslopes with non-constant bedrock slope and non-parallel plan shape. We apply the model to nine characteristic hillslope types with three different profile curvatures (concave, straight, convex) and three different plan shapes (convergent, parallel, divergent). In the presented model, the unsaturated storage has been calculated based on the unit head gradient assumption. To relax this assumption and to investigate the effect of neglecting the variations of unsaturated storage on the assessment of slope stability in the transient case, we also combine a coupled model of saturated and unsaturated storage and the infinite slope stability method. The results show that the variations of the unsaturated zone storage do not play a critical role in hillslope stability. Therefore, it can be concluded that the presented dynamic slope stability model (HSB-SM) can be used safely for slope stability analysis on complex hillslopes. Our results show that after a certain period of rainfall the convergent hillslopes with concave and straight profiles become unstable more quickly than others, whilst divergent convex hillslopes remain stable (even after intense rainfall). In addition, the relation between subsurface flow and hillslope stability has been investigated. Our analyses show that the minimum safety factor (FS) occurs when the rate of subsurface flow is a maximum. In fact, by increasing the subsurface flow, stability decreases for all hillslope shapes. Copyright © 2008 John Wiley & Sons, Ltd. [source] Application of New Organic Fuels in the Direct MgAl2O4 Combustion SynthesisEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2008Robert Iano Abstract The paper presents a new version of MgAl2O4 solution-combustion synthesis, based on the individual reactivity of Mg(NO3)2 and Al(NO3)3 with respect to various fuels. Beside the traditionally used fuels (urea, glycine, ,-alanine), new organic reducing agents [monoethanolamine, triethanolamine, tris(hydroxymethyl)aminomethane and triethylenetetramine] have also been used. The study of the individual reactivities of Mg(NO3)2 and Al(NO3)3 with respect to each of the previously mentioned fuels suggested that there is a predilection of the two metal nitrates for certain fuels: urea is the optimum fuel for Al(NO3)3, whereas monoethanolamine represents the most suitable fuel for Mg(NO3)2. It has been shown by X-ray diffraction and thermal analysis that the use of a single fuel in the MgAl2O4 low-temperature combustion synthesis leads to the formation of an amorphous powder. In this case, the formation of pure crystalline MgAl2O4 requires a subsequent thermal treatment at 900 °C with 1 h soaking time. On the other hand, the use of fuel mixtures containing urea and monoethanolamine or urea and ,-alanine proved to be the rational solution for the direct formation of MgAl2O4. It has been shown that, by using the above-mentioned fuel mixtures, one can obtain pure nanocrystalline MgAl2O4 straight from the combustion reaction, no additional calcination being necessary. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Is there a role of visual cortex in spatial hearing?EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2004Ulrike Zimmer Abstract The integration of auditory and visual spatial information is an important prerequisite for accurate orientation in the environment. However, while visual spatial information is based on retinal coordinates, the auditory system receives information on sound location in relation to the head. Thus, any deviation of the eyes from a central position results in a divergence between the retinal visual and the head-centred auditory coordinates. It has been suggested that this divergence is compensated for by a neural coordinate transformation, using a signal of eye-in-head position. Using functional magnetic resonance imaging, we investigated which cortical areas of the human brain participate in such auditory,visual coordinate transformations. Sounds were produced with different interaural level differences, leading to left, right or central intracranial percepts, while subjects directed their gaze to visual targets presented to the left, to the right or straight ahead. When gaze was to the left or right, we found the primary visual cortex (V1/V2) activated in both hemispheres. The occipital activation did not occur with sound lateralization per se, but was found exclusively in combination with eccentric eye positions. This result suggests a relation of neural processing in the visual cortex and the transformation of auditory spatial coordinates responsible for maintaining the perceptual alignment of audition and vision with changes in gaze direction. [source] Oligodendroglial tau filament formation in transgenic mice expressing G272V tauEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2001Jürgen Götz Abstract Genetic evidence indicates that several mutations in tau, including G272V, are linked to frontotemporal dementia with parkinsonism. We expressed this mutation in mouse brains by combining a prion protein promoter-driven expression system with an autoregulatory transactivator loop that resulted in high expression of human G272V tau in neurons and in oligodendrocytes. We show that G272V tau can form filaments in murine oligodendrocytes. Electron microscopy established that the filaments were either straight or had a twisted structure; these were 17,20 nm wide and had a periodicity of ,,75 nm. Filament formation was associated with tau phosphorylation at distinct sites, including the AT8 epitope 202/205 in vivo. Immunogold electron microscopy of sarcosyl-extracted spinal cords from G272V transgenic mice using phosphorylation-dependent antibodies AT8 or AT100 identified several sparsely gold-labelled 6-nm filaments. In the spinal cord, fibrillary inclusions were also identified by thioflavin-S fluorescent microscopy in oligodendrocytes and motor neurons. These results establish that expression of the G272V mutation in mice causes oligodendroglial fibrillary lesions that are similar to those seen in human tauopathies. [source] Nanoscopic fatigue and stress corrosion crack growth behaviour in a high-strength stainless steel visualized in situ by atomic force microscopyFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 11 2005K. MINOSHIMA ABSTRACT In situ atomic force microscope (AFM) imaging of the fatigue and stress corrosion (SC) crack in a high-strength stainless steel was performed, under both static and dynamic loading. The AFM systems used were (1) a newly developed AFM-based system for analysing the nanoscopic topographies of environmentally induced damage under dynamic loads in a controlled environment and (2) an AFM system having a large sample stage together with a static in-plane loading device. By using these systems, in situ serial clear AFM images of an environmentally induced crack under loading could be obtained in a controlled environment, such as in dry air for the fatigue and in an aqueous solution for the stress corrosion cracking (SCC). The intergranular static SC crack at the free corrosion had a sharp crack tip when it grew straight along a grain boundary. The in situ AFM observations showed that the fatigue crack grew in a steady manner on the order of sub-micrometre. The same result was obtained for the static SC crack under the free corrosion, growing straight along a grain boundary. In these cases, the crack tip opening displacement (CTOD) remained constant. However, as the static SC crack was approaching a triple grain junction, the growth rate became smaller, the CTOD value increased and the hollow ahead of the crack tip became larger. After the crack passed through the triple grain junction, it grew faster with a lower CTOD value; the changes in the CTOD value agreed with those of the crack growth rate. At the cathodic potential, the static SC crack grew in a zigzag path and in an unsteady manner, showing crack growth acceleration and retardation. This unsteady crack growth was considered to be due to the changes in the local hydrogen content near the crack tip. The changes in the CTOD value also agreed with those of the crack growth rate. The CTOD value in the corrosive environment was influenced by the microstructure of the material and the local hydrogen content, showing a larger scatter band, whereas the CTOD value of the fatigue crack in dry air was determined by the applied stress intensity factor, with a smaller scatter band. In addition, the CTOD value in the corrosive environment under both static and dynamic loading was smaller than that of the fatigue crack; the environmentally induced crack had a sharper crack tip than the fatigue crack in dry air. [source] Influence of anisotropy on a limit load of weld strength overmatched middle cracked tension specimensFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 5 2003S. ALEXANDROV ABSTRACT A plane-strain upper bound limit load solution for weld strength overmatched middle cracked tension specimens (M(T) specimens), is found. It is assumed that the weld material is isotropic, but the base material is orthotropic and its axes of orthotropy are straight and parallel to the axes of symmetry of the specimen. A quadratic orthotropic yield criterion is adopted. The solution is based on a simple discontinuous kinematically admissible velocity field and is an extension of the corresponding solution for the specimen made of isotropic materials. These two solutions are compared to demonstrate the influence of anisotropy on the magnitude of the limit load. [source] Measurement and analysis of wheel loads for design and fatigue evaluation of vehicle chassis componentsFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 12 2002M. DECKER ABSTRACT Using a multiaxial-randomly loaded air-suspension rear-axle for commercial vehicles as an example, this paper gives an insight in the mechanics and interactions of wheel forces and moments, forces acting in the suspension components and the stress response of the axle casing. Taking load-time and stress-time data measured on a prototype vehicle on a test track as a basis, fatigue, frequency and correlation analyses for all relevant manoeuvres and straight-ahead driving situations are performed. Special focus is given to the study and determination of appropriate correlations between the mentioned properties for manoeuvres and straight ahead driving on rough roads. The results point out all decisive load situations which may affect the fatigue behaviour of the axle under operational conditions and were taken into account for the derivation of optimized design solutions, as well as for the experimental verification of the final solution in the test rig. [source] Copper Azide Confined Inside Templated Carbon NanotubesADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Valarie Pelletier Abstract The currently used primary explosives, such as lead azide and lead styphnate, present serious health hazards due to the toxicity of lead. There is a need to replace them with equally energetic but safer-to-handle and more environmentally friendly materials. Copper azide is more environmentally acceptable, but very sensitive and detonates easily from electrostatic charges during handling. If the highly sensitive copper azide is encapsulated within conducting containers, such as anodic aluminum oxide (AAO)-templated carbon nanotubes (CNTs), its sensitivity can be tamed. This work describes a technique for confining energetic copper azide within CNTs. ,5 nm colloidal copper oxide nanoparticles are synthesized and filled into the 200 nm diameter CNTs, produced by template synthesis. The Cu-O inside the CNTs is reduced in hydrogen to copper, and reacted with hydrazoic acid gas to produce copper azide. Upon initiation, the 60 ,m long straight, open-ended CNTs guide decomposition gases along the tube channel without fracturing the nanotube walls. These novel materials have potential for applications as nano-detonators and green primary explosives; they also offer new opportunities for understanding the physics of detonation at the nanoscale. [source] Solution structure of a hydrophobic analogue of the winter flounder antifreeze proteinFEBS JOURNAL, Issue 4 2002Edvards Liepinsh The solution structure of a synthetic mutant type I antifreeze protein (AFP I) was determined in aqueous solution at pH 7.0 using nuclear magnetic resonance (NMR) spectroscopy. The mutations comprised the replacement of the four Thr residues by Val and the introduction of two additional Lys-Glu salt bridges. The antifreeze activity of this mutant peptide, VVVV2KE, has been previously shown to be similar to that of the wild type protein, HPLC6 (defined here as TTTT). The solution structure reveals an ,,helix bent in the same direction as the more bent conformer of the published crystal structure of TTTT, while the side chain ,1 rotamers of VVVV2KE are similar to those of the straighter conformer in the crystal of TTTT. The Val side chains of VVVV2KE assume the same orientations as the Thr side chains of TTTT, confirming the conservative nature of this mutation. The combined data suggest that AFP I undergoes an equilibrium between straight and bent helices in solution, combined with independent equilibria between different side chain rotamers for some of the amino acid residues. The present study presents the first complete sequence-specific resonance assignments and the first complete solution structure determination by NMR of any AFP I protein. [source] Campanile trevorjacksoni sp. nov., (Mollusca: Gastropoda) from the Eocene of Jamaica: at last, a name for the first fossil used in intercontinental biostratigraphic correlation (de la Beche 1827)GEOLOGICAL JOURNAL, Issue 5 2008Roger W. Portell Abstract A new species of giant fossil gastropod belonging to the genus Campanile, Campanile trevorjacksoni sp. nov., is described from the Lower Eocene Stettin Formation of the Yellow Limestone Group of Jamaica. Over 180 years ago, internal moulds of these giant gastropods were first reported from the Eocene of Jamaica and referred to as Cerithium; it is only with the discovery of an external mould of the shell spire that it can now be removed from open nomenclature. The ornate shell of C. trevorjacksoni has flat-sided to slightly rounded whorls; straight, impressed sutures; seven beaded, spiral cords per whorl and a nodose subsutural ridge in the more adapertural part of the shell. This sculpture differentiates C. trevorjacksoni from other Paleogene Campanile species. In 1827, de la Beche included C. trevorjacksoni (as Cerithium) in a list of over 20 taxa with which he correlated his white limestone formation (including the Yellow Limestone Group of modern use) with the (Eocene) Calcaire grossier of the Paris Basin. These specimens are lost, but re-examination of de la Beche's list suggests his identifications were mostly reasonable. Copyright © 2008 John Wiley & Sons, Ltd. [source] 1D and 3D Ionic Liquid,Aluminum Hydroxide Hybrids Prepared via an Ionothermal Process,ADVANCED FUNCTIONAL MATERIALS, Issue 14 2007S. Park Abstract Room-temperature ionic liquids (RTILs) are used as hierarchically multifunctional components by employing them not only as templates and co-solvents for fabricating nanostructured materials but also proton conductors for electrochemical devices. RTIL/aluminum hydroxide (RTIL,Al) hybrids containing various nanometer-sized shapes, including 1D nanorods with hexagonal tips, straight and curved nanofibers, nanofibers embedded in a porous network, and 3D octahedral-, polyhedral-, and angular spherical shapes are synthesized via a one-pot ionothermal process. The structures or shapes of the RTIL,Al hybrids are related to the anionic moieties, alkyl chain length of the RTILs, and the humidity during fabrication. In particular, the introduction of water molecules into the interface led to 3D isotropic growth of the hybrids by influencing intermolecular interactions between the RTILs and the building blocks. The shapes of the nanohybrids fabricated from RTILs containing short alkyl chains were dependent on the types of anions and on the level of humidity. These results indicate that the cooperative interactions between RTILs and aluminum hydroxides induces emerging shape-controlled hybrids. The shape-controlled nanohybrids show enhanced electrochemical properties compared to those of a conventional hybrid prepared by mixing RTILs and aluminum hydroxides, exhibiting tenfold or higher proton conductivity under anhydrous condition and thermal stability as a result of the continuous proton conduction channel and the one-pot-assembled nanoconfinement. This method is expected to be a useful technique for controlling the diverse shapes of nanometer-sized crystalline inorganic materials for a variety of applications, such as fuel cells, solar cells, rechargeable batteries, and biosensors. [source] Magnetic-Field-Assisted Electrospinning of Aligned Straight and Wavy Polymeric NanofibersADVANCED MATERIALS, Issue 22 2010Yaqing Liu Aligned straight and wavy fibers of biodegradable poly(D,L-lactic- co -glycolic acid) (PLGA) are fabricated using a magnetic-field-assisted electrospinning method. PLGA fibrous matrices prepared by this method can guide the growth of pluripotent murine mesenchymal stem cells. While the stem cells on the randomly oriented fibers adapt pseudo-sphere-like shape, those on aligned fibers exhibit elongated morphology along the long axes (see figure). [source] Biocompatible Silk Printed Optical WaveguidesADVANCED MATERIALS, Issue 23 2009Sara T. Parker Biocompatible silk optical waveguides are fabricated by direct-write assembly and demonstrated to guide light in both straight and curved architectures. These waveguides can easily be doped or functionalized with bioactive molecules, and are promising materials for biophotonic devices. [source] Distance from file tip to the major apical foramen in relation to the numeric meter reading on the display of three different electronic apex locatorsINTERNATIONAL ENDODONTIC JOURNAL, Issue 12 2009R. A. Higa Abstract Aim, To establish and compare the relationship between the distance from the file tip to the apical foramen and the numeric meter reading on the display of three different electronic apex locators (EALs). Methodology, A total of 12 extracted intact, straight, single-rooted human teeth with complete roots were used. The actual root canal length (AL) was determined after access preparation. For the electronic measurements with each EAL, silicon stops were fixed with auto-polymerizing resin to size 15 K-files at AL and 0.5, 1, 2, 3, 4 mm short of AL. The data was analysed by two-way anova and Tukey's honestly significant difference (HSD) test for multiple comparisons amongst EALs. Additionally, one-way anova and Tukey's HSD test were carried out for multiple comparisons amongst the measurements of each EAL. Results, There was a statistically significant difference amongst all EALs in indicating the position of file tips in relation to the major foramen (P < 0.05). The correlation between the meter reading and the position of the file tip from the apical foramen was statistically significant in the three EALs. There were significant differences amongst the measurements at distances from 0 to 2 mm in Justy III. In Dentaport, significant differences were found from 0 to 1 mm. However, the E-Magic Finder showed significant differences from 0 to 0.5 mm. Conclusions, Justy III was more capable of displaying the intracanal position of the file tip from the major foramen in mm whilst advancing through the root canal during electronic measurements than the Dentaport and E-Magic Finder Deluxe. [source] The influence of root canal shape on the sealing ability of two root canal sealersINTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2006A. Juhász Abstract Aim, To evaluate the influence of root canal form on the sealing ability of two root canal sealers. Methodology, Twenty radiographically confirmed straight and 20 curved root canals were prepared with a stepback hand filing technique. Root canal aberrations created during preparation were determined by the use of double exposure radiographic technique. The prepared canals were filled with lateral condensation of gutta-percha and one or other of two root canal sealers (Pulp Canal Sealer and Sealapex). Leakage along the apical 10 mm of roots was measured with a fluid transport model at 1, 3, 6, 9 and 12-month intervals. Results, There were no statistically significant differences between straight and curved root canals (P > 0.05) for prevalence of root canal transportation. The prevalence of apical transportation was 80% in the straight and 85% in the curved root canals. A complete seal was more frequently observed in straight canals compared with curved canals. Utilizing the ,* index, analysis showed the filling with Sealapex allowed more leakage than Pulp Canal Sealer at 1 year. Conclusion, Under the conditions of the study, root canal form influenced short-term sealing ability. In the long-term the seal was affected by the sealer rather than root canal form. [source] The effectiveness of syringe irrigation and ultrasonics to remove debris from simulated irregularities within prepared root canal wallsINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2004S.-J. Lee Abstract Aim, To compare the ability of syringe irrigation and ultrasonic irrigation to remove artificially placed dentine debris from simulated canal irregularities within prepared root canals. Methodology, After canal enlargement, twelve canines were split longitudinally into two halves. On the wall of one half of each root canal a standard groove of 4 mm in length, 0.2 mm in width and 0.5 mm in depth was cut, 2,6 mm from the apex, to simulate uninstrumented canal extensions. On the wall of the other half, three standard saucer-shaped depressions of 0.3 mm in diameter and 0.5 mm in depth were cut at 2, 4 and 6 mm from the apex to simulate uninstrumented canal irregularities. Each groove and depression were filled with dentine debris mixed with 2% NaOCl to simulate a situation when dentine debris accumulates in uninstrumented canal extensions and irregularities during canal preparation. Each tooth was re-assembled by reconnecting the two halves, using wire and an impression putty material. Two per cent NaOCl was then delivered into each canal either using syringe irrigation (n = 8) or using ultrasonic irrigation (n = 8). Before and after irrigation, images of the two halves of the canal wall were taken, using a microscope and a digital camera, after which they were scanned into a PC as TIFF images. The amount of remaining dentine debris in the grooves and depressions was evaluated by using a scoring system between 0,3: the higher the score, the more the debris. The data were analysed by means of the Mann,Whitney U -test. Results, Both forms of irrigation reduced the debris score significantly. The debris score was statistically significantly lower after ultrasonic irrigation than after syringe irrigation (P = 0.002 for grooves, P = 0.047 for depressions). Conclusion, Ultrasonic irrigation ex vivo is more effective than syringe irrigation in removing artificially created dentine debris placed in simulated uninstrumented extensions and irregularities in straight, wide root canals. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||